Search results for: iron removal

Authors: M. Zielinski, M. Debowski, P. Rusanowska, A. Glowacka-Gil, M. Zielinska, A. Cydzik-Kwiatkowska, J. Kazimierowicz

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Technologies for the micro-biogas plant with heating and mixing systems are presented as a part of the Research Coordination for a Low-Cost Biomethane Production at Small and Medium Scale Applications (Record Biomap). The main objective of the Record Biomap project is to build a network of operators and scientific institutions interested in cooperation and the development of promising technologies in the sector of small and medium-sized biogas plants. The activities carried out in the project will bridge the gap between research and market and reduce the time of implementation of new, efficient technological and technical solutions. Reactor with simultaneously mixing and heating system is a concrete tank with a rectangular cross-section. In the reactor, heating is integrated with the mixing of substrate and anaerobic sludge. This reactor is solution dedicated for substrates with high solids content, which cannot be introduced to the reactor with pumps, even with positive displacement pumps. Substrates are poured to the reactor and then with a screw pump, they are mixed with anaerobic sludge. The pumped sludge, flowing through the screw pump, is simultaneously heated by a heat exchanger. The level of the fermentation sludge inside the reactor chamber is above the bottom edge of the cover. Cover of the reactor is equipped with the screw pump driver. Inside the reactor, an electric motor is installed that is driving a screw pump. The heated sludge circulates in the digester. The post-fermented sludge is collected using a drain well. The inlet to the drain well is below the level of the sludge in the digester. The biogas is discharged from the reactor by the biogas intake valve located on the cover. The technology is very useful for fermentation of lignocellulosic biomass and substrates with high content of dry mass (organic wastes). The other technology is a reactor for micro-biogas plant with a pressure mixing system. The reactor has a form of plastic or concrete tank with a circular cross-section. The effective mixing of sludge is ensured by profiled at 90° bottom of the tank. Substrates for fermentation are supplied by an inlet well. The inlet well is equipped with a cover that eliminates odour release. The introduction of a new portion of substrates is preceded by pumping of digestate to the disposal well. Optionally, digestate can gravitationally flow to digestate storage tank. The obtained biogas is discharged into the separator. The valve supplies biogas to the blower. The blower presses the biogas from the fermentation chamber in such a way as to facilitate the introduction of a new portion of substrates. Biogas is discharged from the reactor by valve that enables biogas removal but prevents suction from outside the reactor.

Keywords: biogas, digestion, heating system, mixing system

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Authors: Olga Smilevska Spasova, Katerina Boshkovska, Gorica Popova, Mirjana Popovska

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Introduction: Pneumonia is an infection of the pulmonary parenchyma. HPIV 3 is one of four viruses that is a member of the Paramyxoviridae family designated types 1-4 that have a nonsegmented, single-stranded RNA genome with a lipid-containing envelope. They are spread from the respiratory tract by aerosolized secretions or by direct contact with secretions. Type 3 is endemic and can cause serious illness in immunocompromised patients. Illness caused by parainfluenza occurs shortly after inoculation with the virus. The level of immunoglobulin A antibody in serum is the best predictor of susceptibility to infection. Streptococcus pneumonia or pneumococcus is a Gram-positive, spherical bacteria, usually found in pairs and it is a member of the genus Streptococcus. Streptococcus pneumonia resides asymptomatically in healthy carriers typically colonizing the respiratory tract, sinuses, and nasal cavity. In individuals with weaker immune systems like young infants, pneumococcal bacterium is the most common cause of community-acquired pneumonia in the world. Case Report: The aim is to present a case of lower respiratory tract infection in an infant caused by parainfluenza virus 3, S. pneumonia and undifferentiated gram-negative bacteria that was successfully treated. The infant is with a history of recurrent episodes of wheezing in the past 3mounts.Infant of 10months presents 2weeks before admittance with high fever, runny nose, and cough. The primary pediatrician prescribed oral cefpodoxime for 10days and inhaled salbutamol. Two days before admittance in hospital the infant with high fever, cough, and difficulty breathing. At admittance, infant is pale, anxious with rapid respirations, cough, wheezing and tachycardia. On auscultation: vesicular breathing sounds with high pitched wheezing and on the right coarse crackles. Investigations: Blood analysis: RBC: 4, 7 x1012L, WBC: 8,3x109L: Neut: 42.73% Lym: 41.57%, Hgb: 9.38 g/dl MCV: 62.7fl, MCH: 20.0pg MCHC: 31.8 g/dl RDW: 18.7% Plt-307.9 x109LCRP: 2,5mg/l, serum iron-7.92umol/l, O2sat-97% on blood gas analysis, puls-125/min.X-ray of chest with hyperinflationand right pericardial consolidation. Microbiological analysis of sputum sample is positive for undifferentiated gram-negative bacteria (colonizer)–resistant to cefotaxime, ampicillin, cefoxitin, sulfamet.+trimetoprim and sensitive to amikacin, gentamicin, and ciprofloxacin. Molecular multiplex RT-PCR for 19 viruses and multiplex PCR for 7 bacteria test for respiratory pathogens positive for Parainfluenza virus 3(Ct=22.73), Streptococcus pneumonia (Ct=26.75).IED: IgG-9.31g/l, IgA-0.351g/l, IgM-0.86g/l. Therapy: Treatment was started with inhaled salbutamol, intravenous antibiotic cefotaxime as well as systemic corticosteroids. On day 7 because of slow clinical resolution of chest auscultation findings and an etiologic clue with a positive sputum sample for resistant undifferentiated gram negative bacteria, a second intravenous antibiotic was administered amikacin. The infant is discharged on day 14 with resolution of clinical findings. Conclusion: Mixed co-infections with respiratory viruses and bacteria in immunocompromised infants are likely to lead to a more severe form of community acquired pneumonia that will need hospitalization.

Keywords: HPIV- 3, infant, pneumonia, S. pneumonia, x-ray chest

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Authors: Tatiana V. Melnikova, Lyudmila P. Polyakova, Alla A. Oudalova

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As a result of environmental pollution, the production of agriculture and foodstuffs inevitably contain residual amounts of Persistent Organic Pollutants (POP). The special attention must be given to organic pollutants, including various organochlorinated pesticides (OCP). Among priorities, OCP is DDT (and its metabolite DDE), alfa-HCH, gamma-HCH (lindane). The control of these substances spends proceeding from requirements of sanitary norms and rules. During too time often is lost sight of that the primary product can pass technological processing (in particular irradiation treatment) as a result of which transformation of physicochemical forms of initial polluting substances is possible. The goal of the present work was to study the OCP radiation degradation at a various gamma-radiation dosimetric characteristics. The problems posed for goal achievement: to evaluate the content of the priority of OCPs in food; study the character the degradation of OCP in model solutions (with micro concentrations commensurate with the real content of their agricultural and food products) depending upon dosimetric characteristics of gamma-radiation. Qualitative and quantitative analysis of OCP in food and model solutions by gas chromatograph Varian 3400 (Varian, Inc. (USA)); chromatography-mass spectrometer Varian Saturn 4D (Varian, Inc. (USA)) was carried out. The solutions of DDT, DDE, alpha- and gamma- isomer HCH (0.01, 0.1, 1 ppm) were irradiated on "Issledovatel" (60Co) and "Luch - 1" (60Co) installations at a dose 10 kGy with a variation of dose rate from 0.0083 up to 2.33 kGy/sec. It was established experimentally that OCP residual concentration in individual samples of food products (fish, milk, cereal crops, meat, butter) are evaluated as 10-1-10-4 mg/kg, the value of which depends on the factor-sensations territory and natural migration processes. The results were used in the preparation of model solutions OCP. The dependence of a degradation extent of OCP from a dose rate gamma-irradiation has complex nature. According to our data at a dose 10 kGy, the degradation extent of OCP at first increase passes through a maximum (over the range 0.23 – 0.43 Gy/sec), and then decrease with the magnification of a dose rate. The character of the dependence of a degradation extent of OCP from a dose rate is kept for various OCP, in polar and nonpolar solvents and does not vary at the change of concentration of the initial substance. Also in work conditions of the maximal radiochemical yield of OCP which were observed at having been certain: influence of gamma radiation with a dose 10 kGy, in a range of doses rate 0.23 – 0.43 Gy/sec; concentration initial OCP 1 ppm; use of solvent - 2-propanol after preliminary removal of oxygen. Based on, that at studying model solutions of OCP has been established that the degradation extent of pesticides and qualitative structure of OCP radiolysis products depend on a dose rate, has been decided to continue researches radiochemical transformations OCP into foodstuffs at various of doses rate.

Keywords: degradation extent, dosimetric characteristics, gamma-radiation, organochlorinated pesticides, persistent organic pollutants

Procedia PDF Downloads 248

Authors: Z. Karahaliloğlu, C. Hacker, M. Demirbilek, G. Seide, E. B. Denkbaş, T. Gries

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Currently, textile industry has played an important role in world’s economy, especially in developing countries. Dyes and pigments used in textile industry are significant pollutants. Most of theirs are azo dyes that have chromophore (-N=N-) in their structure. There are many methods for removal of the dyes from wastewater such as chemical coagulation, flocculation, precipitation and ozonation. But these methods have numerous disadvantages and alternative methods are needed for wastewater decolorization. Titanium-mediated photodegradation has been used generally due to non-toxic, insoluble, inexpensive, and highly reactive properties of titanium dioxide semiconductor (TiO2). Melt electrospinning is an attractive manufacturing process for thin fiber production through electrospinning from PP (Polyprophylene). PP fibers have been widely used in the filtration due to theirs unique properties such as hydrophobicity, good mechanical strength, chemical resistance and low-cost production. In this study, we aimed to investigate the effect of titanium nanoparticle localization and amine modification on the dye degradation. The applicability of the prepared chemical activated composite and pristine fabrics for a novel treatment of dyeing wastewater were evaluated.In this study, a photocatalyzer material was prepared from nTi (titanium dioxide nanoparticles) and PP by a melt-electrospinning technique. The electrospinning parameters of pristine PP and PP/nTi nanocomposite fabrics were optimized. Before functionalization with nTi, the surface of fabrics was activated by a technique using glutaraldehyde (GA) and polyethyleneimine to promote the dye degredation. Pristine PP and PP/nTi nanocomposite melt-electrospun fabrics were characterized using scanning electron microscopy (SEM) and X-Ray Photon Spectroscopy (XPS). Methyl orange (MO) was used as a model compound for the decolorization experiments. Photocatalytic performance of nTi-loaded pristine and nanocomposite melt-electrospun filters was investigated by varying initial dye concentration 10, 20, 40 mg/L). nTi-PP composite fabrics were successfully processed into a uniform, fibrous network of beadless fibers with diameters of 800±0.4 nm. The process parameters were determined as a voltage of 30 kV, a working distance of 5 cm, a temperature of the thermocouple and hotcoil of 260–300 ºC and a flow rate of 0.07 mL/h. SEM results indicated that TiO2 nanoparticles were deposited uniformly on the nanofibers and XPS results confirmed the presence of titanium nanoparticles and generation of amine groups after modification. According to photocatalytic decolarization test results, nTi-loaded GA-treated pristine or nTi-PP nanocomposite fabric filtern have superior properties, especially over 90% decolorization efficiency at GA-treated pristine and nTi-PP composite PP fabrics. In this work, as a photocatalyzer for wastewater treatment, surface functionalized with nTi melt-electrospun fabrics from PP were prepared. Results showed melt-electrospun nTi-loaded GA-tretaed composite or pristine PP fabrics have a great potential for use as a photocatalytic filter to decolorization of wastewater and thus, requires further investigation.

Keywords: titanium oxide nanoparticles, polyprophylene, melt-electrospinning

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Authors: Sarah Maiter

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Heightened globalization, migration, displacement of citizens, and refugee needs is putting increasing demand for approaches to social services for diverse populations that responds to families to ensure the safety and protection of vulnerable members while providing supports and services. Along with this social works re-focus on socially just approaches to practice increasingly asks social workers to consider the challenging circumstances of families when providing services rather than a focus on individual shortcomings alone. Child protection workers then struggle to ensure safety of children while assessing the needs of families. This assessment can prove to be difficult when providing services to immigrant, refugee, and racially diverse families as understanding of and familiarity with these families is often limited. Furthermore, child protection intervention in western countries is state mandated having legal authority when intervening in the lives of families where child protection concerns have been identified. Within this context, racialized immigrant and refugee families are at risk of misunderstandings that can result in interventions that are overly intrusive, unhelpful, and harsh. Research shows disproportionality and overrepresentation of racial and ethnic minorities, and immigrant families in the child protection system. Reasons noted include: a) possibilities of racial bias in reporting and substantiating abuse, b) struggles on the part of workers when working with families from diverse ethno-racial backgrounds and who are immigrants and may have limited proficiency in the national language of the country, c) interventions during crisis and differential ongoing services for these families, d) diverse contexts of these families that poses additional challenges for families and children, and e) possible differential definitions of child maltreatment. While cultural and ethnic diversity in child rearing approaches have been cited as contributors to child protection concerns, this approach should be viewed cautiously as it can result in stereotyping and generalizing that then results in inappropriate assessment and intervention. However, poverty and the lack of social supports, both well-known contributors to child protection concerns, also impact these families disproportionately. Child protection systems, therefore, need to continue to examine policy and practice approaches with these families that ensures safety of children while balancing the needs of families. This presentation provides data from several research studies that examined definitions of child maltreatment among a sample of racialized immigrant families, experiences of a sample of immigrant families with the child protection system, concerns of a sample of child protection workers in the provision of services to these families, and struggles of families in the transitions to their new country. These studies, along with others provide insights into areas of consideration for practice that can contribute to safety for children while ensuring just and equitable responses that have greater potential for keeping families together rather than premature apprehension and removal of children to state care.

Keywords: child protection, child welfare services, immigrant families, racial and ethnic diversity

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Authors: Daniel Thompson, Muhammad Peerbux, Sophie Cerutti, Hansraj Bookun

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Introduction: Dialysis access is a key component of the care of patients with end stage renal failure. In our institution, a combined service of vascular surgeons and nephrologists are responsible for the creation and maintenance of arteriovenous fisultas (AVF), tenckhoff cathethers and Hickman/permcath lines. This poster investigates the last 10 years of dialysis access surgery conducted at St. Vincent’s Hospital Melbourne. Method: A cross-sectional retrospective analysis was conducted of patients of St. Vincent’s Hospital Melbourne (Victoria, Australia) utilising data collection from the Australasian Vascular Audit (Australian and New Zealand Society for Vascular Surgery). Descriptive demographic analysis was carried out as well as operation type, length of hospital stays, postoperative deaths and need for reoperation. Results: 2085 patients with renal failure were operated on between the years of 2011 and 2020. 1315 were male (63.1%) and 770 were female (36.9%). The mean age was 58 (SD 13.8). 92% of patients scored three or greater on the American Society of Anesthiologiests classification system. Almost half had a history of ischaemic heart disease (48.4%), more than half had a history of diabetes (64%), and a majority had hypertension (88.4%). 1784 patients had a creatinine over 150mmol/L (85.6%), the rest were on dialysis (14.4%). The most common access procedure was AVF creation, with 474 autologous AVFs and 64 prosthetic AVFs. There were 263 Tenckhoff insertions. We performed 160 cadeveric renal transplants. The most common location for AVF formation was brachiocephalic (43.88%) followed by radiocephalic (36.7%) and brachiobasilic (16.67%). Fistulas that required re-intervention were most commonly angioplastied (n=163), followed by thrombectomy (n=136). There were 107 local fistula repairs. Average length of stay was 7.6 days, (SD 12). There were 106 unplanned returns to theatre, most commonly for fistula creation, insertion of tenckhoff or permacath removal (71.7%). There were 8 deaths in the immediately postoperative period. Discussion: Access to dialysis is vital for patients with end stage kidney disease, and requires a multidisciplinary approach from both nephrologists, vascular surgeons, and allied health practitioners. Our service provides a variety of dialysis access methods, predominately fistula creation and tenckhoff insertion. Patients with renal failure are heavily comorbid, and prolonged hospital admission following surgery is a source of significant healthcare expenditure. AVFs require careful monitoring and maintenance for ongoing utility, and our data reflects a multitude of operations required to maintain usable access. The requirement for dialysis is growing worldwide and our data demonstrates a local experience in access, with preferred methods, common complications and the associated surgical interventions.

Keywords: dialysis, fistula, nephrology, vascular surgery

Procedia PDF Downloads 112

Authors: Mazaher Yarmohamadi-Vasel, Ali Reza Modarresi-Alama, Sahar Shabzendedara

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Purpose/Objectives: The first purpose was synthesize Poly(N-(sulfophenyl)aniline) nanoflowers (PSANFLs) and Poly(N-(sulfophenyl)aniline) nanofibers/titanium dioxide nanoparticles ((PSANFs/TiO2NPs) by a solid-state mechano-chemical reaction and template-free method and use them in hybrid solar cell. Also, our second aim was to increase the solubility and the processability of conjugated nanomaterials in water through polar functionalized materials. poly[N-(4-sulfophenyl)aniline] is easily soluble in water because of the presence of polar groups of sulfonic acid in the polymer chain. Materials/Methods: Iron (III) chloride hexahydrate (FeCl3∙6H2O) were bought from Merck Millipore Company. Titanium oxide nanoparticles (TiO2, <20 nm, anatase) and Sodium diphenylamine-4-sulfonate (99%) were bought from Sigma-Aldrich Company. Titanium dioxide nanoparticles paste (PST-20T) was prepared from Sharifsolar Co. Conductive glasses coated with indium tin oxide (ITO) were bought from Xinyan Technology Co (China). For the first time we used the solid-state mechano-chemical reaction and template-free method to synthesize Poly(N-(sulfophenyl)aniline) nanoflowers. Moreover, for the first time we used the same technique to synthesize nanocomposite of Poly(N-(sulfophenyl)aniline) nanofibers and titanium dioxide nanoparticles (PSANFs/TiO2NPs) also for the first time this nanocomposite was synthesized. Examining the results of electrochemical calculations energy gap obtained by CV curves and UV–vis spectra demonstrate that PSANFs/TiO2NPs nanocomposite is a p-n type material that can be used in photovoltaic cells. Doctor blade method was used to creat films for three kinds of hybrid solar cells in terms of different patterns like ITO│TiO2NPs│Semiconductor sample│Al. In the following, hybrid photovoltaic cells in bilayer and bulk heterojunction structures were fabricated as ITO│TiO2NPs│PSANFLs│Al and ITO│TiO2NPs│PSANFs /TiO2NPs│Al, respectively. Fourier-transform infrared spectra, field emission scanning electron microscopy (FE-SEM), ultraviolet-visible spectra, cyclic voltammetry (CV) and electrical conductivity were the analysis that used to characterize the synthesized samples. Results and Conclusions: FE-SEM images clearly demonstrate that the morphology of the synthesized samples are nanostructured (nanoflowers and nanofibers). Electrochemical calculations of band gap from CV curves demonstrated that the forbidden band gap of the PSANFLs and PSANFs/TiO2NPs nanocomposite are 2.95 and 2.23 eV, respectively. I–V characteristics of hybrid solar cells and their power conversion efficiency (PCE) under 100 mWcm−2 irradiation (AM 1.5 global conditions) were measured that The PCE of the samples were 0.30 and 0.62%, respectively. At the end, all the results of solar cell analysis were discussed. To sum up, PSANFLs and PSANFLs/TiO2NPs were successfully synthesized by an affordable and straightforward mechanochemical reaction in solid-state under the green condition. The solubility and processability of the synthesized compounds have been improved compared to the previous work. We successfully fabricated hybrid photovoltaic cells of synthesized semiconductor nanostructured polymers and TiO2NPs as different architectures. We believe that the synthesized compounds can open inventive pathways for the development of other Poly(N-(sulfophenyl)aniline based hybrid materials (nanocomposites) proper for preparing new generation solar cells.

Keywords: mechanochemical synthesis, PSANFLs, PSANFs/TiO2NPs, solar cell

Procedia PDF Downloads 66

Authors: Gunta Resevica, Nikita Zrelovs, Ivars Silamikelis, Ieva Kalnciema, Helvijs Niedra, Gunārs Lācis, Toms Bartulsons, Inga Moročko-Bičevska, Arturs Stalažs, Kristīne Drevinska, Andris Zeltins, Ina Balke

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Newly discovered viruses provide novel knowledge for basic phytovirus research, serve as tools for biotechnology and can be helpful in identification of epidemic outbreaks. Blackcurrant-associated rhabdovirus (BCaRV) have been discovered in USA germplasm collection samples from Russia and France. As it was reported in one accession originating from France it is unclear whether the material was already infected when it entered in the USA or it became infected while in collection in the USA. Due to that BCaRV was definite as non-EU viruses. According to ICTV classification BCaRV is representative of Blackcurrant betanucleorhabdovirus specie in genus Betanucleorhabdovirus (family Rhabdoviridae). Nevertheless, BCaRV impact on the host, transmission mechanisms and vectors are still unknown. In RNA-seq data pool from Ribes plants resistance gene study by high throughput sequencing (HTS) we observed differences between sample group gene transcript heat maps. Additional analysis of the whole data pool (total 393660492 of 150 bp long read pairs) by rnaSPAdes v 3.13.1 resulted into 14424 bases long contig with an average coverage of 684x with shared 99.5% identity to the previously reported first complete genome of BCaRV (MF543022.1) using EMBOSS Needle. This finding proved BCaRV presence in EU and indicated that it might be relevant pathogen. In this study leaf tissue from twelve asymptomatic blackcurrant cv. Mara Eglite plants (negatively tested for blackcurrant reversion virus (BRV)) from Dobele, Latvia (56°36'31.9"N, 23°18'13.6"E) was collected and used for total RNA isolation with RNeasy Plant Mini Kit with minor modifications, followed by plant rRNA removal by a RiboMinus Plant Kit for RNA-Seq. HTS libraries were prepared using MGI Easy RNA Directional Library Prep Set for 16 reactions to obtain 150 bp pair-end reads. Libraries were pooled, circularized and cleaned and sequenced on DNBSEQ-G400 using PE150 flow cell. Additionally, all samples were tested by RT-PCR, and amplicons were directly sequenced by Sanger-based method. The contig representing the genome of BCaRV isolate Mara Eglite was deposited at European Nucleotide Archive under accession number OU015520. Those findings indicate a second evidence on the presence of this particular virus in the EU and further research on BCaRV prevalence in Ribes from other geographical areas should be performed. As there are no information on BCaRV impact on the host this should be investigated, regarding the fact that mixed infections with BRV and nucleorhabdoviruses are reported.

Keywords: BCaRV, Betanucleorhabdovirus, Ribes, RNA-seq

Procedia PDF Downloads 183

Authors: Preethi Kumari P., Shetty Prakasha, Rao Suma A.

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Mild steel has been widely employed as construction materials for pipe work in the oil and gas production such as down hole tubular, flow lines and transmission pipelines, in chemical and allied industries for handling acids, alkalis and salt solutions due to its excellent mechanical property and low cost. Acid solutions are widely used for removal of undesirable scale and rust in many industrial processes. Among the commercially available acids hydrochloric acid is widely used for pickling, cleaning, de-scaling and acidization of oil process. Mild steel exhibits poor corrosion resistance in presence of hydrochloric acid. The high reactivity of mild steel in presence of hydrochloric acid is due to the soluble nature of ferrous chloride formed and the cementite phase (Fe3C) normally present in the steel is also readily soluble in hydrochloric acid. Pitting attack is also reported to be a major form of corrosion in mild steel in the presence of high concentrations of acids and thereby causing the complete destruction of metal. Hydrogen from acid reacts with the metal surface and makes it brittle and causes cracks, which leads to pitting type of corrosion. The use of chemical inhibitor to minimize the rate of corrosion has been considered to be the first line of defense against corrosion. In spite of long history of corrosion inhibition, a highly efficient and durable inhibitor that can completely protect mild steel in aggressive environment is yet to be realized. It is clear from the literature review that there is ample scope for the development of new organic inhibitors, which can be conveniently synthesized from relatively cheap raw materials and provide good inhibition efficiency with least risk of environmental pollution. The aim of the present work is to evaluate the electrochemical parameters for the corrosion inhibition behavior of an aromatic hydrazide derivative, 4-hydroxy- N '-[(E)-1H-indole-2-ylmethylidene)] benzohydrazide (HIBH) on mild steel in 2M hydrochloric acid using Tafel polarization and electrochemical impedance spectroscopy (EIS) techniques at 30-60 °C. The results showed that inhibition efficiency increased with increase in inhibitor concentration and decreased marginally with increase in temperature. HIBH showed a maximum inhibition efficiency of 95 % at 8×10-4 M concentration at 30 °C. Polarization curves showed that HIBH act as a mixed-type inhibitor. The adsorption of HIBH on mild steel surface obeys the Langmuir adsorption isotherm. The adsorption process of HIBH at the mild steel/hydrochloric acid solution interface followed mixed adsorption with predominantly physisorption at lower temperature and chemisorption at higher temperature. Thermodynamic parameters for the adsorption process and kinetic parameters for the metal dissolution reaction were determined.

Keywords: electrochemical parameters, EIS, mild steel, tafel polarization

Procedia PDF Downloads 335

Authors: Leigh G. Hayden, Susan E. Shepley, Cristina Passarelli, William Tingo

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Introduction: Sensory interventions are popular therapeutic and recreational approaches for people living with all stages of dementia. However, it is unknown which sensory interventions are used to achieve which outcomes across all subtypes of dementia. Methods: To address this gap, we conducted a scoping review of sensory interventions for people living with dementia. We conducted a search of the literature for any article published in English from 1 January 1990 to 1 June 2019, on any sensory or multisensory intervention targeted to people living with any kind of dementia, which reported on patient health outcomes. We did not include complex interventions where only a small aspect was related to sensory stimulation. We searched the databases Medline, CINHAL, and Psych Articles using our institutional discovery layer. We conducted all screening in duplicate to reduce Type 1 and Type 2 errors. The data from all included papers were extracted by one team member, and audited by another, to ensure consistency of extraction and completeness of data. Results: Our initial search captured 7654 articles, and the removal of duplicates (n=5329), those that didn’t pass title and abstract screening (n=1840) and those that didn’t pass full-text screening (n=281) resulted in 174 articles included. The countries with the highest publication in this area were the United States (n=59), the United Kingdom (n=26) and Australia (n=15). The most common type of interventions were music therapy (n=36), multisensory rooms (n=27) and multisensory therapies (n=25). Seven articles were published in the 1990’s, 55 in the 2000’s, and the remainder since 2010 (n=112). Discussion: Multisensory rooms have been present in the literature since the early 1990’s. However, more recently, nature/garden therapy, art therapy, and light therapy have emerged since 2008 in the literature, an indication of the increasingly diverse scholarship in the area. The least popular type of intervention is a traditional food intervention. Taste as a sensory intervention is generally avoided for safety reasons, however it shows potential for increasing quality of life. Agitation, behavior, and mood are common outcomes for all sensory interventions. However, light therapy commonly targets sleep. The majority (n=110) of studies have very small sample sizes (n=20 or less), an indicator of the lack of robust data in the field. Additional small-scale studies of the known sensory interventions will likely do little to advance the field. However, there is a need for multi-armed studies which directly compare sensory interventions, and more studies which investigate the use of layering sensory interventions (for example, adding an aromatherapy component to a lighting intervention). In addition, large scale studies which enroll people at early stages of dementia will help us better understand the potential of sensory and multisensory interventions to slow the progression of the disease.

Keywords: sensory interventions, dementia, scoping review

Procedia PDF Downloads 134

Authors: Iryna P. Dzieciuch, Michael D. Putman

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Humidity is known to degrade Navy ship electronic equipment, especially in hot moist environments. If left untreated, it can cause significant and permanent damage. Even rigorous inspection and frequent clean-up would not prevent further equipment contamination and degradation because of the constant presence of favorable growth conditions for many microorganisms. Generally, relative humidity levels of less than 60% will inhibit corrosion in electronic equipment, but because NAVY electronics often operate in hot and humid environments, prevention via dehumidification is not always possible. Currently, there is no defined research that fully describes key mechanisms which cause electronics and its coating degradation. The corrosive action of most bacteria is mainly developed through (i) mycelium adherence to the metal plates, (ii) facilitation the formation of pitting areas, (iii) production of organic acids such as citric, iso-citric, cis-aconitic, alpha-ketoglutaric, which are corrosive to electronic equipment and its components. Our approach studies corrosive action in electronic equipment: circuit-board, wires and connections that are exposed in the humid environment that gets worse during condensation. In our new approach the technical task is built on work with the bacterial communities in public areas, bacterial genetics, bioinformatics, biostatistics and Scanning Electron Microscopy (SEM) of corroded circuit boards. Based on these methods, we collect and examine environmental samples from biofilms of the corroded and non-corroded sites, where bacterial contamination of electronic equipment, such as machine racks and shore boats, is an ongoing concern. Sample collection and sample analysis is focused on addressing the key questions identified above through the following tasks: laboratory sample processing and evaluation under scanning electron microscopy, initial sequencing and data evaluation; bioinformatics and data analysis. Preliminary results from scanning electron microscopy (SEM) have revealed that metal particulates and alloys in corroded samples consists mostly of Tin ( < 40%), Silicon ( < 4%), Sulfur ( < 1%), Aluminum ( < 2%), Magnesium ( < 2%), Copper ( < 1%), Bromine ( < 2%), Barium ( <1%) and Iron ( < 2%) elements. We have also performed X 12000 magnification of the same sites and that proved existence of undisrupted biofilm organelles and crystal structures. Non-corrosion sites have revealed high presence of copper ( < 47%); other metals remain at the comparable level as on the samples with corrosion. We have performed X 1000 magnification on the non-corroded at the sites and have documented formation of copper crystals. The next step of this study, is to perform metagenomics sequencing at all sites and to compare bacterial composition present in the environment. While copper is nontoxic to the living organisms, the process of bacterial adhesion creates acidic environment by releasing citric, iso-citric, cis-aconitic, alpha-ketoglutaric acidics, which in turn release copper ions Cu++, which that are highly toxic to the bacteria and higher order living organisms. This phenomenon, might explain natural “antibiotic” properties that are lacking in elements such as tin. To prove or deny this hypothesis we will use next - generation sequencing (NGS) methods to investigate types and growth cycles of bacteria that from bacterial biofilm the on corrosive and non-corrosive samples.

Keywords: bacteria, biofilm, circuit board, copper, corrosion, electronic equipment, organic acids, tin

Procedia PDF Downloads 160

Authors: Riya Bose, Ashok Bera, Manas R. Parida, Anirudhha Adhikari, Basamat S. Shaheen, Erkki Alarousu, Jingya Sun, Tom Wu, Osman M. Bakr, Omar F. Mohammed

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This work reports visualization of charge carrier dynamics on the surface of copper indium gallium selenide (CIGSe) nanocrystals in real space and time using four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and correlates it with the optoelectronic properties of the nanocrystals. The surface of the nanocrystals plays a key role in controlling their applicability for light emitting and light harvesting purposes. Typically for quaternary systems like CIGSe, which have many desirable attributes to be used for optoelectronic applications, relative abundance of surface trap states acting as non-radiative recombination centre for charge carriers remains as a major bottleneck preventing further advancements and commercial exploitation of these nanocrystals devices. Though ultrafast spectroscopic techniques allow determining the presence of picosecond carrier trapping channels, because of relative larger penetration depth of the laser beam, only information mainly from the bulk of the nanocrystals is obtained. Selective mapping of such ultrafast dynamical processes on the surfaces of nanocrystals remains as a key challenge, so far out of reach of purely optical probing time-resolved laser techniques. In S-UEM, the optical pulse generated from a femtosecond (fs) laser system is used to generate electron packets from the tip of the scanning electron microscope, instead of the continuous electron beam used in the conventional setup. This pulse is synchronized with another optical excitation pulse that initiates carrier dynamics in the sample. The principle of S-UEM is to detect the secondary electrons (SEs) generated in the sample, which is emitted from the first few nanometers of the top surface. Constructed at different time delays between the optical and electron pulses, these SE images give direct and precise information about the carrier dynamics on the surface of the material of interest. In this work, we report selective mapping of surface dynamics in real space and time of CIGSe nanocrystals applying 4D S-UEM. We show that the trap states can be considerably passivated by ZnS shelling of the nanocrystals, and the carrier dynamics can be significantly slowed down. We also compared and discussed the S-UEM kinetics with the carrier dynamics obtained from conventional ultrafast time-resolved techniques. Additionally, a direct effect of the state trap removal can be observed in the enhanced photoresponse of the nanocrystals after shelling. Direct observation of surface dynamics will not only provide a profound understanding of the photo-physical mechanisms on nanocrystals’ surfaces but also enable to unlock their full potential for light emitting and harvesting applications.

Keywords: 4D scanning ultrafast microscopy, charge carrier dynamics, nanocrystals, optoelectronics, surface passivation, trap states

Procedia PDF Downloads 293

Authors: Rabbia Idrees, Ananda Maiti, Saurabh Garg, Muhammad Bilal Amin

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IoT devices are the basic building blocks of IoT network that generate enormous volume of real-time and high-speed data to help organizations and companies to take intelligent decisions. To integrate this enormous data from multisource and transfer it to the appropriate client is the fundamental of IoT development. The handling of this huge quantity of devices along with the huge volume of data is very challenging. The IoT devices are battery-powered and resource-constrained and to provide energy efficient communication, these IoT devices go sleep or online/wakeup periodically and a-periodically depending on the traffic loads to reduce energy consumption. Sometime these devices get disconnected due to device battery depletion. If the node is not available in the network, then the IoT network provides incomplete, missing, and inaccurate data. Moreover, many IoT applications, like vehicle tracking and patient tracking require the IoT devices to be mobile. Due to this mobility, If the distance of the device from the sink node become greater than required, the connection is lost. Due to this disconnection other devices join the network for replacing the broken-down and left devices. This make IoT devices dynamic in nature which brings uncertainty and unreliability in the IoT network and hence produce bad quality of data. Due to this dynamic nature of IoT devices we do not know the actual reason of abnormal data. If data are of poor-quality decisions are likely to be unsound. It is highly important to process data and estimate data quality before bringing it to use in IoT applications. In the past many researchers tried to estimate data quality and provided several Machine Learning (ML), stochastic and statistical methods to perform analysis on stored data in the data processing layer, without focusing the challenges and issues arises from the dynamic nature of IoT devices and how it is impacting data quality. A comprehensive review on determining the impact of dynamic nature of IoT devices on data quality is done in this research and presented a data quality model that can deal with this challenge and produce good quality of data. This research presents the data quality model for the sensors monitoring water quality. DBSCAN clustering and weather sensors are used in this research to make data quality model for the sensors monitoring water quality. An extensive study has been done in this research on finding the relationship between the data of weather sensors and sensors monitoring water quality of the lakes and beaches. The detailed theoretical analysis has been presented in this research mentioning correlation between independent data streams of the two sets of sensors. With the help of the analysis and DBSCAN, a data quality model is prepared. This model encompasses five dimensions of data quality: outliers’ detection and removal, completeness, patterns of missing values and checks the accuracy of the data with the help of cluster’s position. At the end, the statistical analysis has been done on the clusters formed as the result of DBSCAN, and consistency is evaluated through Coefficient of Variation (CoV).

Keywords: clustering, data quality, DBSCAN, and Internet of things (IoT)

Procedia PDF Downloads 137

Authors: Amin Salighehdar, Ziwen Ye, Mingzhe Liu, Ionut Florescu, Alan F. Blumberg

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Storm surge is an abnormal water level caused by a storm. Accurate prediction of a storm surge is a challenging problem. Researchers developed various ensemble modeling techniques to combine several individual forecasts to produce an overall presumably better forecast. There exist some simple ensemble modeling techniques in literature. For instance, Model Output Statistics (MOS), and running mean-bias removal are widely used techniques in storm surge prediction domain. However, these methods have some drawbacks. For instance, MOS is based on multiple linear regression and it needs a long period of training data. To overcome the shortcomings of these simple methods, researchers propose some advanced methods. For instance, ENSURF (Ensemble SURge Forecast) is a multi-model application for sea level forecast. This application creates a better forecast of sea level using a combination of several instances of the Bayesian Model Averaging (BMA). An ensemble dressing method is based on identifying best member forecast and using it for prediction. Our contribution in this paper can be summarized as follows. First, we investigate whether the ensemble models perform better than any single forecast. Therefore, we need to identify the single best forecast. We present a methodology based on a simple Bayesian selection method to select the best single forecast. Second, we present several new and simple ways to construct ensemble models. We use correlation and standard deviation as weights in combining different forecast models. Third, we use these ensembles and compare with several existing models in literature to forecast storm surge level. We then investigate whether developing a complex ensemble model is indeed needed. To achieve this goal, we use a simple average (one of the simplest and widely used ensemble model) as benchmark. Predicting the peak level of Surge during a storm as well as the precise time at which this peak level takes place is crucial, thus we develop a statistical platform to compare the performance of various ensemble methods. This statistical analysis is based on root mean square error of the ensemble forecast during the testing period and on the magnitude and timing of the forecasted peak surge compared to the actual time and peak. In this work, we analyze four hurricanes: hurricanes Irene and Lee in 2011, hurricane Sandy in 2012, and hurricane Joaquin in 2015. Since hurricane Irene developed at the end of August 2011 and hurricane Lee started just after Irene at the beginning of September 2011, in this study we consider them as a single contiguous hurricane event. The data set used for this study is generated by the New York Harbor Observing and Prediction System (NYHOPS). We find that even the simplest possible way of creating an ensemble produces results superior to any single forecast. We also show that the ensemble models we propose generally have better performance compared to the simple average ensemble technique.

Keywords: Bayesian learning, ensemble model, statistical analysis, storm surge prediction

Procedia PDF Downloads 307

Authors: Akmez Nabeerasool, Michaelis Massaros, Nigel Brown, David Sanderson, David Parocki, Charlotte Thompson, Mike Lodge, Mikael Khan

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The provision of clean and safe drinking water is of paramount importance and is a basic human need. Water scarcity coupled with tightening of regulations and the inability of current treatment technologies to deal with emerging contaminants and Pharmaceuticals and personal care products means that alternative treatment technologies that are viable and cost effective are required in order to meet demand and regulations for clean water supplies. Logistically, the application of water treatment in rural areas presents unique challenges due to the decentralisation of abstraction points arising from low population density and the resultant lack of infrastructure as well as the need to treat water at the site of use. This makes it costly to centralise treatment facilities and hence provide potable water direct to the consumer. Furthermore, across the UK there are segments of the population that rely on a private water supply which means that the owner or user(s) of these supplies, which can serve one household to hundreds, are responsible for the maintenance. The treatment of these private water supply falls on the private owners, and it is imperative that a chemical free technological solution that can operate unattended and does not produce any waste is employed. Arvia’s patented advanced oxidation technology combines the advantages of adsorption and electrochemical regeneration within a single unit; the Organics Destruction Cell (ODC). The ODC uniquely uses a combination of adsorption and electrochemical regeneration to destroy organics. Key to this innovative process is an alternative approach to adsorption. The conventional approach is to use high capacity adsorbents (e.g. activated carbons with high porosities and surface areas) that are excellent adsorbents, but require complex and costly regeneration. Arvia’s technology uses a patent protected adsorbent, Nyex™, which is a non-porous, highly conductive, graphite based adsorbent material that enables it to act as both the adsorbent and as a 3D electrode. Adsorbed organics are oxidised and the surface of the Nyex™ is regenerated in-situ for further adsorption without interruption or replacement. Treated water flows from the bottom of the cell where it can either be re-used or safely discharged. Arvia™ Technology Ltd. has trialled the application of its tertiary water treatment technology in treating reservoir water abstracted near Glasgow, Scotland, with promising results. Several other pilot plants have also been successfully deployed at various locations in the UK showing the suitability and effectiveness of the technology in removing recalcitrant organics (including pharmaceuticals, steroids and hormones), COD and colour.

Keywords: Arvia™ process, adsorption, water treatment, electrochemical oxidation

Procedia PDF Downloads 262

Authors: Azza A. Ali, Toqa M. Elnahhas, Abeer I. Abd El-Fattah, Mona M. Kamal, Karema Abu-Elfotuh

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Background: Environmental pollution with the different aluminium (Al) containing compounds especially those in industrial waste water exposes people to higher than normal levels of Al that represents an environmental risk factor. Cosmetics, Al ware, and containers are also sources of Al besides some foods and food additives. In addition to its known neurotoxicity, Al affects other body structures like skeletal system, blood cells, liver and kidney. Accumulation of Al in kidney and liver induces nephrotoxicity and hepatotoxicity. Coenzyme Q10 (CoQ10) is a pseudo-vitamin substance primarily present in the mitochondria. It is a powerful antioxidant and acts as radical scavenger. Wheat grass is a natural product that contains carbohydrates, proteins, vitamins, minerals, enzymes and has antioxidant, anti-inflammatory, anticancer and cardiovascular protection activities. Cocoa is an excellent source of iron, potent antioxidants and can protect against many diseases. Vinpocetine is an antioxidant and anti inflammatory while zinc is an essential trace element involved in cell division and its deficiency is observed in many types of liver disease. Objective: To evaluate and compare the potency of different drugs (CoQ10, wheatgrass, cocoa, vinpocetine and zinc) against nephro- and hepato-toxicity induced by Al in rats. Methods: Rats were divided to seven groups and received daily for three weeks either saline for control group or AlCl3 (70 mg/kg, IP) for Al-toxicity model groups. Five groups of Al-toxicity model (treated groups) were orally received together with Al each of the following; CoQ10 (200mg/kg), wheat grass (100mg/kg), cocoa powder (24mg/kg), vinpocetine (20mg/kg) or zinc (32mg/kg). Biochemical changes in the serum level of Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate deshydrogenase (LDH) as well as total bilirubin, lipids, cholesterol, triglycerides, glucose, proteins, creatinine and urea were measured. Liver and kidney specimens from all groups were also collected for the assessment of hepatic and nephrotic level of inflammatory mediators (TNF-α, IL-6β, nuclear factor kappa B (NF-κB), Caspase-3, oxidative parameters (MDA, SOD, TAC, NO) and DNA fragmentation. Histopathological changes in liver and kidney were also evaluated. Results: Three weeks of AlCl3 (70 mg/kg, IP) exposure induced nephro- and hepato-toxicity in rats. Treatment by the all used drugs showed protection against hazards of AlCl3. The protective effects were indicated by the significant decrease in ALT, AST, ALP, LDH as well as total bilirubin, lipids, cholesterol, triglycerides, glucose, creatinine and urea levels which were increased by Al. Liver and kidney of the treated groups showed decrease in MDA, NO, TNF-α, IL-6β, NF-κB, caspase-3 and DNA fragmentation which were increased by Al, together with significant increase in total proteins, SOD and TAC which were decreased by Al. The protection against both nephro- and hepato-toxicity was more pronounced especially with CoQ10 and wheat grass than the other used drugs. Histopathological examinations confirmed the biochemical results of toxicity and of protection. Conclusion: Protection from nephrotoxicity, hepatotoxicity and the consequent degenerations induced by Al can be achieved by using different drugs as CoQ10, wheatgrass, cocoa, vinpocetine and zinc, but CoQ10 as well as wheat grass possesses the most superior protection.

Keywords: aluminum, nephrotoxicity, hepatotoxicity, coenzyme Q10, wheatgrass, cocoa, vinpocetine, zinc

Procedia PDF Downloads 337

Authors: P.P. Rupasinghe, A.H. Farid

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The Aleutian mink disease virus (AMDV, Carnivore amdoparvovirus 1) causes persistent infection, plasmacytosis, and formation and deposition of immune complexes in various organs in adult mink, leading to glomerulonephritis, arteritis and sometimes death. The disease has no cure nor an effective vaccine, and identification and culling of mink positive for anti-AMDV antibodies have not been successful in controlling the infection in many countries. The failure to eradicate the virus from infected farms may be caused by keeping false-negative individuals on the farm, virus transmission from wild animals, or neighboring farms. The identification of sources of infection, which can be performed by comparing viral sequences, is important in the success of viral eradication programs. High mutation rates could cause inaccuracies when viral sequences are used to trace back an infection to its origin. There is no published information on the mutation rate of AMDV either in vivo or in vitro. The in vivo estimation is the most accurate method, but it is difficult to perform because of the inherent technical complexities, namely infecting live animals, the unknown numbers of viral generations (i.e., infection cycles), the removal of deleterious mutations over time and genetic drift. The objective of this study was to determine the mutation rate of AMDV on which no information was available. A homogenate was prepared from the spleen of one naturally infected American mink (Neovison vison) from Nova Scotia, Canada (parental template). The near full-length genome of this isolate (91.6%, 4,143 bp) was bidirectionally sequenced. A group of black mink was inoculated with this homogenate (descendant mink). Spleen sampled were collected from 10 descendant mink after 16 weeks post-inoculation (wpi) and from anther 10 mink after 176 wpi, and their near-full length genomes were bi-directionally sequenced. Sequences of these mink were compared with each other and with the sequence of the parental template. The number of nucleotide substitutions at 176 wpi was 3.1 times greater than that at 16 wpi (113 vs 36) whereas the estimates of mutation rate at 176 wpi was 3.1 times lower than that at 176 wpi (2.85×10-3 vs 9.13×10-4 substitutions/ site/ year), showing a decreasing trend in the mutation rate per unit of time. Although there is no report on in vivo estimate of the mutation rate of DNA viruses in animals using the same method which was used in the current study, these estimates are at the higher range of reported values for DNA viruses determined by various techniques. These high estimates are logical based on the wide range of diversity and pathogenicity of AMDV isolates. The results suggest that increases in the number of nucleotide substitutions over time and subsequent divergence make it difficult to accurately trace back AMDV isolates to their origin when several years elapsed between the two samplings.

Keywords: Aleutian mink disease virus, American mink, mutation rate, nucleotide substitution

Procedia PDF Downloads 123

Authors: Ankit Khurana

Abstract:

The sufficient heat storage capacity or ability to dissipate heat is the most decisive parameter to have an effective and efficient functioning of Friction-based Brake Disc systems. The primary aim of the research was to analyse the effect of multiple coatings on lightweight disk rotors surface which not only alleviates the mass of vehicle & also, augments heat transfer. This research is projected to aid the automobile fraternity with an enunciated view over the thermal aspects in a braking system. The results of the project indicate that with the advent of modern coating technologies a brake system’s thermal curtailments can be removed and together with forced convection, heat transfer processes can see a drastic improvement leading to increased lifetime of the brake rotor. Other advantages of modifying the surface of a lightweight rotor substrate will be to reduce the overall weight of the vehicle, decrease the risk of thermal brake failure (brake fade and fluid vaporization), longer component life, as well as lower noise and vibration characteristics. A mathematical model was constructed in MATLAB which encompassing the various thermal characteristics of the proposed coatings and substrate materials required to approximate the heat flux values in a free and forced convection environment; resembling to a real-time braking phenomenon which could easily be modelled into a full cum scaled version of the alloy brake rotor part in ABAQUS. The finite element of a brake rotor was modelled in a constrained environment such that the nodal temperature between the contact surfaces of the coatings and substrate (Wrought Aluminum alloy) resemble an amalgamated solid brake rotor element. The initial results obtained were for a Plasma Electrolytic Oxidized (PEO) substrate wherein the Aluminum alloy gets a hard ceramic oxide layer grown on its transitional phase. The rotor was modelled and then evaluated in real-time for a constant ‘g’ braking event (based upon the mathematical heat flux input and convective surroundings), which reflected the necessity to deposit a conducting coat (sacrificial) above the PEO layer in order to inhibit thermal degradation of the barrier coating prematurely. Taguchi study was then used to bring out certain critical factors which may influence the maximum operating temperature of a multi-coated brake disc by simulating brake tests: a) an Alpine descent lasting 50 seconds; b) an Autobahn stop lasting 3.53 seconds; c) a Six–high speed repeated stop in accordance to FMVSS 135 lasting 46.25 seconds. Thermal Barrier coating thickness and Vane heat transfer coefficient were the two most influential factors and owing to their design and manufacturing constraints a final optimized model was obtained which survived the 6-high speed stop test as per the FMVSS -135 specifications. The simulation data highlighted the merits for preferring Wrought Aluminum alloy 7068 over Grey Cast Iron and Aluminum Metal Matrix Composite in coherence with the multiple coating depositions.

Keywords: lightweight brakes, surface modification, simulated braking, PEO, aluminum

Procedia PDF Downloads 407

Authors: M. A. Rahman, A. T. Ohta, H. V. Trinh, J. Hyvl

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Atmospheric pressure and oxygen (O2) concentration are critical life support parameters for human-occupied aerospace vehicles and habitats. Various medical conditions may require medical O2; for example, the American Medical Association has determined that commercial air travel exposes passengers to altitude-related hypoxia and gas expansion. It may cause some passengers to experience significant symptoms and medical complications during the flight, requiring supplemental medical-grade O2 to maintain adequate tissue oxygenation and prevent hypoxemic complications. Although supplemental medical grade O2 is a successful lifesaver for respiratory and cardiac failure, O2-enriched exhaled air can contain more than 95 % O2, increasing the likelihood of a fire. In an aerospace environment, a localized high concentration O2 bubble forms around a patient being treated for hypoxia, increasing the cabin O2 beyond the safe limit. To address this problem, this work describes a medical O2 delivery system that can reduce the O2 concentration from patient-exhaled O2-rich air to safe levels while maintaining the prescribed O2 administration to the patient. The O2 delivery system is designed to be a part of the medical O2 kit. The system uses cationic multimetallic cobalt complexes to reversibly, selectively, and stoichiometrically chemisorb O2 from the exhaled air. An air-release sub-system monitors the exhaled air, and as soon the O2 percentage falls below 21%, the air is released to the room air. The O2-enriched exhaled air is channeled through a layer of porous, thin-film heaters coated with the cobalt complex. The complex absorbs O2, and when saturated, the complex is heated to 100°C using the thin-film heater. Upon heating, the complex desorbs O2 and is once again ready to absorb or remove the excess O2 from exhaled air. The O2 absorption is a sub-second process, and desorption is a multi-second process. While heating at 0.685 °C/sec, the complex desorbs ~90% O2 in 110 sec. These fast reaction times mean that a simultaneous absorb/desorb process in the O2 delivery system will create a continuous absorption of O2. Moreover, the complex can concentrate O2 by a factor of 160 times that in air and desorb over 90% of the O2 at 100°C. Over 12 cycles of thermogravimetry measurement, less than 0.1% decrease in reversibility in O2 uptake was observed. The 1 kg complex can desorb over 20L of O2, so simultaneous O2 desorption by 0.5 kg of complex and absorption by 0.5 kg of complex can potentially continuously remove 9L/min O2 (~90% desorbed at 100°C) from exhaled air. The complex is synthesized and characterized for reversible O2 absorption and efficacy. The complex changes its color from dark brown to light gray after O2 desorption. In addition to thermogravimetric analysis, the O2 absorption/desorption cycle is characterized using optical imaging, showing stable color changes over ten cycles. The complex was also tested at room temperature in a low O2 environment in its O2 desorbed state, and observed to hold the deoxygenated state under these conditions. The results show the feasibility of using the complex for reversible O2 absorption in the proposed fire safe medical O2 delivery system.

Keywords: fire risk, medical oxygen, oxygen removal, reversible absorption

Procedia PDF Downloads 102

Authors: Silvia Di Giacomo, Marcello Locatelli, Simone Carradori, Francesco Cacciagrano, Chiara Toniolo, Gabriela Mazzanti, Luisa Mannina, Stefania Cesa, Antonella Di Sotto

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Hyperglycemia represents the main pathogenic factor in the development of diabetes complications and has been found associated with mitochondrial dysfunction and oxidative stress, which in turn increase cell dysfunction. Therefore, counteract oxidative species appears to be a suitable strategy for preventing the hyperglycemia-induce cell damage and support the pharmacotherapy of diabetes and metabolic diseases. Antidiabetic potential of many food sources has been linked to the presence of polyphenolic metabolites, particularly flavonoids such as quercetin and its glycosylated form rutin. In line with this evidence, in the present study, we assayed the potential anti-hyperglycemic activity of an ethyl acetate extract from the peel of Punica granatum L. var. Dente di Cavallo (PGE), a fruit well known to traditional medicine for the beneficial properties of its edible juice. The effect of the extract on the glucidic metabolism has been evaluated by assessing its ability to inhibit α-amylase and α-glucosidase, two digestive enzymes responsible for the hydrolysis of dietary carbohydrates: their inhibition can delay the carbohydrate digestion and reduce glucose absorption, thus representing an important strategy for the management of hyperglycemia. Also, the PGE ability to block the release of advanced glycated end-products (AGEs), whose accumulation is known to be responsible for diabetic vascular complications, was studied. The iron-reducing and chelating activities, which are the primary mechanisms by which AGE inhibitors stop their metal-catalyzed formation, were evaluated as possible antioxidant mechanisms. At last, the phenolic content of PGE was characterized by chromatographic and spectrophotometric methods. Our results displayed the ability of PGE to inhibit α-amylase enzyme with a similar potency to the positive control: the IC₅₀ values were 52.2 (CL 27.7 - 101.2) µg/ml and 35.6 (CL 22.8 - 55.5) µg/ml for acarbose and PGE, respectively. PGE also inhibited the α-glucosidase enzyme with about a 25 higher potency than the positive controls of acarbose and quercetin. Furthermore, the extract exhibited ferrous and ferric ion chelating ability, with a maximum effect of 82.1% and 80.6% at a concentration of 250 µg/ml respectively, and reducing properties, reaching the maximum effect of 80.5% at a concentration of 10 µg/ml. At last, PGE was found able to inhibit the AGE production (maximum inhibition of 82.2% at the concentration of 1000 µg/ml), although with lower potency with respect to the positive control rutin. The phytochemical analysis of PGE displayed the presence of high levels of total polyphenols, tannins, and flavonoids, among which ellagic acid, gallic acid and catechin were identified. Altogether these data highlight the ability of PGE to control the carbohydrate metabolism at different levels, both by inhibiting the metabolic enzymes and by affecting the AGE formation likely by chelating mechanisms. It is also noteworthy that peel from pomegranate, although being a waste of juice production, can be reviewed as a nutraceutical source. In conclusion, present results suggest the possible role of PGE as a remedy for preventing hyperglycemia complications and encourage further in vivo studies.

Keywords: anti-hyperglycemic activity, antioxidant properties, nutraceuticals, polyphenols, pomegranate

Procedia PDF Downloads 184

Authors: Michael Mederle, Heinz Bernhardt

Abstract:

The Management of machine fleets or autonomous vehicle control will considerably increase efficiency in future agricultural production. Especially entire process chains, e.g. harvesting complexes with several interacting combine harvesters, grain carts, and removal trucks, provide lots of optimization potential. Organization and pre-planning ensure to get these efficiency reserves accessible. One way to achieve this is to optimize infield path planning. Particularly autonomous machinery requires precise specifications about infield logistics to be navigated effectively and process optimized in the fields individually or in machine complexes. In the past, a lot of theoretical optimization has been done regarding infield logistics, mainly based on field geometry. However, there are reasons why farmers often do not apply the infield strategy suggested by mathematical route planning tools. To make the computational optimization more useful for farmers this study focuses on these influencing factors by expert interviews. As a result practice-oriented navigation not only to the field but also within the field will be possible. The survey study is intended to cover the entire range of German agriculture. Rural mixed farms with simple technology equipment are considered as well as large agricultural cooperatives which farm thousands of hectares using track guidance and various other electronic assistance systems. First results show that farm managers using guidance systems increasingly attune their infield-logistics on direction giving obstacles such as power lines. In consequence, they can avoid inefficient boom flippings while doing plant protection with the sprayer. Livestock farmers rather focus on the application of organic manure with its specific requirements concerning road conditions, landscape terrain or field access points. Cultivation of sugar beets makes great demands on infield patterns because of its particularities such as the row crop system or high logistics demands. Furthermore, several machines working in the same field simultaneously influence each other, regardless whether or not they are of the equal type. Specific infield strategies always are based on interactions of several different influences and decision criteria. Single working steps like tillage, seeding, plant protection or harvest mostly cannot be considered each individually. The entire production process has to be taken into consideration to detect the right infield logistics. One long-term objective of this examination is to integrate the obtained influences on infield strategies as decision criteria into an infield navigation tool. In this way, path planning will become more practical for farmers which is a basic requirement for automatic vehicle control and increasing process efficiency.

Keywords: autonomous vehicle control, infield logistics, path planning, process optimizing

Procedia PDF Downloads 232

Authors: Hasan Atakan Sengul, Nergis Canturk, Bahar Erbas

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Drinking water is indispensable for life. With increasing awareness of communities, the content of drinking water and tap water has been a matter of curiosity. The presence of Bisphenol-A is the top one when content curiosity is concerned. The most used chemical worldwide for production of polycarbonate plastics and epoxy resins is Bisphenol-A. People are exposed to Bisphenol-A chemical, which disrupts the endocrine system, almost every day. Each year it is manufactured an average of 5.4 billion kilograms of Bisphenol-A. Linear formula of Bisphenol-A is (CH₃)₂C(C₆H₄OH)₂, its molecular weight is 228.29 and CAS number is 80-05-7. Bisphenol-A is known to be used in the manufacturing of plastics, along with various chemicals. Bisphenol-A, an industrial chemical, is used in the raw materials of packaging mate-rials in the monomers of polycarbonate and epoxy resins. The pass through the nutrients of Bisphenol-A substance happens by packaging. This substance contaminates with nutrition and penetrates into body by consuming. International researches show that BPA is transported through body fluids, leading to hormonal disorders in animals. Experimental studies on animals report that BPA exposure also affects the gender of the newborn and its time to reach adolescence. The extent to what similar endocrine disrupting effects are on humans is a debate topic in many researches. In our country, detailed studies on BPA have not been done. However, it is observed that 'BPA-free' phrases are beginning to appear on plastic packaging such as baby products and water carboys. Accordingly, this situation increases the interest of the society about the subject; yet it causes information pollution. In our country, all national and international studies on exposure to BPA have been examined and Ankara province has been designated as testing region. To assess the effects of plastic use in daily habits of people and the plastic amounts removed out of the body, the results of the survey conducted with volunteers who live in Ankara has been analyzed with Sciex appliance by means of LC-MS/MS in the laboratory and the amount of exposure and BPA removal have been detected by comparing the results elicited before. The results have been compared with similar studies done in international arena and the relation between them has been exhibited. Consequently, there has been found no linear correlation between the amount of BPA in drinking water and the amount of BPA in urine. This has also revealed that environmental exposure and the habits of daily plastic use have also direct effects a human body. When the amount of BPA in drinking water is considered; minimum 0.028 µg/L, maximum 1.136 µg/L, mean 0.29194 µg/L and SD(standard deviation)= 0.199 have been detected. When the amount of BPA in urine is considered; minimum 0.028 µg/L, maximum 0.48 µg/L, mean 0.19181 µg/L and SD= 0.099 have been detected. In conclusion, there has been found no linear correlation between the amount of BPA in drinking water and the amount of BPA in urine (r= -0.151). The p value of the comparison between drinking water’s and urine’s BPA amounts is 0.004 which shows that there is a significant change and the amounts of BPA in urine is dependent on the amounts in drinking waters (p < 0.05). This has revealed that environmental exposure and daily plastic habits have also direct effects on the human body.

Keywords: analyze of bisphenol-A, BPA, BPA in drinking water, BPA in urine

Procedia PDF Downloads 127

Authors: M. Arun, A. Kannan

Abstract:

Textile industries cater to varied customer preferences and contribute substantially to the economy. However, these textile industries also produce a considerable amount of effluents. Prominent among these are the azo dyes which impart considerable color and toxicity even at low concentrations. Azo dyes are also used as coloring agents in food and pharmaceutical industry. Despite their applications, azo dyes are also notorious pollutants and carcinogens. Popular techniques like photo-degradation, biodegradation and the use of oxidizing agents are not applicable for all kinds of dyes, as most of them are stable to these techniques. Chemical coagulation produces a large amount of toxic sludge which is undesirable and is also ineffective towards a number of dyes. Most of the azo dyes are stable to UV-visible light irradiation and may even resist aerobic degradation. Adsorption has been the most preferred technique owing to its less cost, high capacity and process efficiency and the possibility of regenerating and recycling the adsorbent. Adsorption is also most preferred because it may produce high quality of the treated effluent and it is able to remove different kinds of dyes. However, the adsorption process is influenced by many variables whose inter-dependence makes it difficult to identify optimum conditions. The variables include stirring speed, temperature, initial concentration and adsorbent dosage. Further, the internal diffusional resistance inside the adsorbent particle leads to slow uptake of the solute within the adsorbent. Hence, it is necessary to identify optimum conditions that lead to high capacity and uptake rate of these pollutants. In this work, commercially available activated carbon was chosen as the adsorbent owing to its high surface area. A typical azo dye found in textile effluent waters, viz. the monoazo Acid Orange 10 dye (CAS: 1936-15-8) has been chosen as the representative pollutant. Adsorption studies were mainly focused at obtaining equilibrium and kinetic data for the batch adsorption process at different process conditions. Studies were conducted at different stirring speed, temperature, adsorbent dosage and initial dye concentration settings. The Full Factorial Design was the chosen statistical design framework for carrying out the experiments and identifying the important factors and their interactions. The optimum conditions identified from the experimental model were validated with actual experiments at the recommended settings. The equilibrium and kinetic data obtained were fitted to different models and the model parameters were estimated. This gives more details about the nature of adsorption taking place. Critical data required to design batch adsorption systems for removal of Acid Orange 10 dye and identification of factors that critically influence the separation efficiency are the key outcomes from this research.

Keywords: acid orange 10, activated carbon, optimum adsorption conditions, statistical design

Procedia PDF Downloads 168

Authors: Pietro P. Falciglia, Erica Gagliano, Vincenza Brancato, Alfio Catalfo, Guglielmo Finocchiaro, Guido De Guidi, Stefano Romano, Paolo Roccaro, Federico G. A. Vagliasindi

Abstract:

Cesium-137 (¹³⁷Cs) is a major radionuclide in spent nuclear fuel processing, and it represents the most important cause of contamination related to nuclear accidents. Cesium-137 has long-term radiological effects representing a major concern for the human health. Several physico-chemical methods have been proposed for ¹³⁷Cs removal from impacted water: ion-exchange, adsorption, chemical precipitation, membrane process, coagulation, and electrochemical. However, these methods can be limited by ionic selectivity and efficiency, or they present very restricted full-scale application due to equipment and chemical high costs. On the other hand, adsorption is considered a more cost-effective solution, and activated carbons (ACs) are known as a low-cost and effective adsorbent for a wide range of pollutants among which radionuclides. However, adsorption of Cs onto ACs has been investigated in very few and not exhaustive studies. In addition, exhausted activated carbons are generally discarded in landfill, that is not an eco-friendly and economic solution. Consequently, the regeneration of exhausted ACs must be considered a preferable choice. Several alternatives, including conventional thermal-, solvent-, biological- and electrochemical-regeneration, are available but are affected by several economic or environmental concerns. Microwave (MW) irradiation has been widely used in industrial and environmental applications and it has attracted many attentions to regenerating activated carbons. The growing interest in MW irradiation is based on the passive ability of the irradiated medium to convert a low power irradiation energy into a rapid and large temperature increase if the media presents good dielectric features. ACs are excellent MW-absorbers, with a high mechanical strength and a good resistance towards heating process. This work investigates the feasibility of MW irradiation for the regeneration of Cs-exhausted ACs. Adsorption batch experiments were carried out using commercially available granular activated carbon (GAC), then Cs-saturated AC samples were treated using a controllable bench-scale 2.45-GHz MW oven and investigating different adsorption-regeneration cycles. The regeneration efficiency (RE), weight loss percentage, and textural properties of the AC samples during the adsorption-regeneration cycles were also assessed. Main results demonstrated a relatively low adsorption capacity for Cs, although the feasibility of ACs was strictly linked to their dielectric nature, which allows a very efficient thermal regeneration by MW irradiation. The weight loss percentage was found less than 2%, and an increase in RE after three cycles was also observed. Furthermore, MW regeneration preserved the pore structure of the regenerated ACs. For a deeper exploration of the full-scale applicability of MW regeneration, further investigations on more adsorption-regeneration cycles or using fixed-bed columns are required.

Keywords: adsorption mechanisms, cesium, granular activated carbons, microwave regeneration

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Authors: Simona Dostalova, Pavel Kopel, Marketa Vaculovicova, Vojtech Adam, Rene Kizek

Abstract:

Protein apoferritin seems to be a very promising structure for use as a nanocarrier. It is prepared from intracellular ferritin protein naturally found in most organisms. The role of ferritin proteins is to store and transport ferrous ions. Apoferritin is a hollow protein cage without ferrous ions that can be prepared from ferritin by reduction with thioglycolic acid or dithionite. The structure of apoferritin is composed of 24 protein subunits, creating a sphere with 12 nm in diameter. The inner cavity has a diameter of 8 nm. The drug encapsulation process is based on the response of apoferritin structure to the pH changes of surrounding solution. In low pH, apoferritin is disassembled into individual subunits and its structure is “opened”. It can then be mixed with any desired cytotoxic drug and after adjustment of pH back to neutral the subunits are reconnected again and the drug is encapsulated within the apoferritin particles. Excess drug molecules can be removed by dialysis. The receptors for apoferritin, SCARA5 and TfR1 can be found in the membrane of both healthy and cancer cells. To enhance the specific targeting of apoferritin nanocarrier, it is possible to modify its surface with targeting moieties, such as antibodies. To ensure sterically correct complex, we used a a peptide linker based on a protein G with N-terminus affinity towards Fc region of antibodies. To connect the peptide to the surface of apoferritin, the C-terminus of peptide was made of cysteine with affinity to gold. The surface of apoferritin with encapsulated doxorubicin (ApoDox) was coated either with gold nanoparticles (ApoDox-Nano) or gold (III) chloride hydrate reduced with sodium borohydride (ApoDox-HAu). The applied amount of gold in form of gold (III) chloride hydrate was 10 times higher than in the case of gold nanoparticles. However, after removal of the excess unbound ions by electrophoretic separation, the concentration of gold on the surface of apoferritin was only 6 times higher for ApoDox-HAu in comparison with ApoDox-Nano. Moreover, the reduction with sodium borohydride caused a loss of doxorubicin fluorescent properties (excitation maximum at 480 nm with emission maximum at 600 nm) and thus its biological activity. Fluorescent properties of ApoDox-Nano were similar to the unmodified ApoDox, therefore it was more suited for the intended use. To evaluate the specificity of apoferritin modified with antibodies, we used ELISA-like method with the surface of microtitration plate wells coated by the antigen (goat anti-human IgG antibodies). To these wells, we applied ApoDox without targeting antibodies and ApoDox-Nano modified with targeting antibodies (human IgG antibodies). The amount of unmodified ApoDox on antigen after incubation and subsequent rinsing with water was 5 times lower than in the case of ApoDox-Nano modified with targeting antibodies. The modification of non-gold ApoDox with antibodies caused no change in its targeting properties. It can therefore be concluded that the demonstrated procedure allows us to create nanocarrier with enhanced targeting properties, suitable for nanomedicine.

Keywords: apoferritin, doxorubicin, nanocarrier, targeting antibodies

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Authors: Olatokunbo Yakeem

Abstract:

Human trafficking is a crime against gross violations of human rights. Trafficking in persons is a severe socio-economic dilemma that affects the national and international dimensions. Human trafficking or modern-day-slavery emanated from slavery, and it has been in existence before the 6ᵗʰ century. Today, no country is exempted from dehumanizing human beings, and as a result, it has been an international issue. The United Nations (UN) presented the International Protocol to fight human trafficking worldwide, which brought about the international definition of human trafficking. The protocol is to prevent, suppress, and punish trafficking in persons, especially women and children. The trafficking protocol has a link with transnational organised crime rather than migration. Over a hundred and fifty countries nationwide have enacted their criminal and panel code trafficking legislation from the UN trafficking protocol. Sex trafficking is the most common type of exploitation of women and children. Other forms of this crime involve exploiting vulnerable victims through forced labour, child involvement in warfare, domestic servitude, debt bondage, and organ removal for transplantation. Trafficking of women and children into sexual exploitation represents the highest form of human trafficking than other types of exploitation. Trafficking of women and children can either happen internally or across the border. It affects all kinds of people, regardless of their race, social class, culture, religion, and education levels. However, it is more of a gender-based issue against females. Furthermore, human trafficking can lead to life-threatening infections, mental disorders, lifetime trauma, and even the victim's death. The study's significance is to explore why the root causes of women and children trafficking in Nigeria are based around poverty, entrusting children in the hands of relatives and friends, corruption, globalization, weak legislation, and ignorance. The importance of this study is to establish how the national, regional, and international organisations are using the 3P’s Protection, Prevention, and Prosecution) to tackle human trafficking. The methodology approach for this study will be a qualitative paradigm. The rationale behind this selection is that the qualitative method will identify the phenomenon and interpret the findings comprehensively. The data collection will take the form of semi-structured in-depth interviews through telephone and email. The researcher will use a descriptive thematic analysis to analyse the data by using complete coding. In summary, this study aims to recommend to the Nigerian federal government to include human trafficking as a subject in their educational curriculum for early intervention to prevent children from been coerced by criminal gangs. And the research aims to find the root causes of women and children trafficking. Also, to look into the effectiveness of the strategies in place to eradicate human trafficking globally. In the same vein, the research objective is to investigate how the anti-trafficking bodies such as law enforcement and NGOs collaborate to tackle the upsurge in human trafficking.

Keywords: children, Nigeria, trafficking, women

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Authors: Marian Mihalik, Kornel Csach, Martin Kovalik, Matúš Mihalik, Martina Kubovčíková, Maria Zentková, Martin Vavra, Vladimír Girman, Jaroslav Briančin, Marija Perovic, Marija Boškovic, Magdalena Fitta, Robert Pelka

Abstract:

Current nanomaterials for use in biomedicine are based mainly on iron oxides and on present knowledge on magnetic nanostructures. Manganites can represent another material which can be used optionally. Manganites and their unique electronic properties have been extensively studied in the last decades not only due to fundamental interest but to possible applications of colossal magnetoresistance, magnetocaloric effect, and ferroelectric properties. It was found that the oxygen-reduction reaction on perovskite oxide is intimately connected with metal ion e.g., orbital occupation. The effect of oxygen deviation from the stoichiometric composition on crystal structure was studied very carefully by many authors on LaMnO₃. Depending on oxygen content, the crystal structure changes from orthorhombic one to rhombohedric for oxygen content 3.1. In the case of hole-doped manganites, the change from the orthorhombic crystal structure, which is typical for La1-xCaxMnO3 based manganites, to the rhombohedric crystal structure (La1-xMxMnO₃ where M = K, Ag, and Sr based materials) results in an enormous increase of the Curie temperature. In our paper, we study the effect of oxygen content on crystal structure, thermal, and magnetic properties (including magnetocaloric effect) of La1-xAgxMnO₃nano particle system. The content of oxygen in samples was tuned by heat treatment in different thermal regimes and in various environment (air, oxygen, argon). Water nanosuspensions based on La0.80Ag0.15MnO₃ magnetic particles with the Curie temperature of about 43oC were prepared by two different approaches. First, by using a laboratory circulation mill for milling of powder in the presence of sodium dodecyl sulphate (SDS) and subsequent centrifugation. Second nanosuspension was prepared using an agate bowl, etching in citric acid and HNO3, ultrasound homogeniser, centrifugation, and dextran 40 kDA or 15 kDA as surfactant. Electrostatic stabilisation obtained by the first approach did not offer long term kinetic and aggregation colloidal stability and was unable to compensate for attractive forces between particles under a magnetic field. By the second approach, we prepared suspension oversaturated by dextran 40 kDA for steric stabilisation, with evidence of the presence of superparamagnetic behaviour. Low concentration of nanoparticles and not ideal coverage of nanoparticles impacting the stability of ferrofluids was the disadvantage of this approach. Strong steric stabilisation was observable at alcaic conditions under pH = ~10. Application of dextran 15 kDA leads to relatively stable ferrofluid with pH around physiological conditions, but desegregation of powder by HNO₃ was not effective enough, and the average size of fragments was to large of about 150 nm, and we did not see any signature of superparamagnetic behaviour. The prepared ferrofluids were characterised by scanning and transition microscope method, thermogravimetry, magnetization, and AC susceptibility measurements. Specific Absorption Rate measurements were undertaken on powder as well on ferrofluids in order to estimate the potential application of La₀.₈₀Ag₀.₁₅MnO₃ magnetic particles based ferrofluid for hyperthermia. Our complex study contains an investigation of biocompatibility and potential biohazard of this material.

Keywords: manganites, magnetic nanoparticles, oxygen content, magnetic phase transition, magnetocaloric effect, ferrofluid, hyperthermia

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Authors: Totsaporn Suwannaruang, Kitirote Wantala

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The purposes of this research were to synthesize titanium dioxide photocatalyst doped with nitrogen (N-doped TiO₂) by hydrothermal method and to test the photocatalytic degradation of paraquat under UV and visible light illumination. The effect of calcination treatment temperature on their physical and chemical properties and photocatalytic efficiencies were also investigated. The characterizations of calcined N-doped TiO₂ photocatalysts such as specific surface area, textural properties, bandgap energy, surface morphology, crystallinity, phase structure, elements and state of charges were investigated by Brunauer, Emmett, Teller (BET) and Barrett, Joyner, Halenda (BJH) equations, UV-Visible diffuse reflectance spectroscopy (UV-Vis-DRS) by using the Kubelka-Munk theory, Wide-angle X-ray scattering (WAXS), Focussed ion beam scanning electron microscopy (FIB-SEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS), respectively. The results showed that the effect of calcination temperature was significant on surface morphology, crystallinity, specific surface area, pore size diameter, bandgap energy and nitrogen content level, but insignificant on phase structure and oxidation state of titanium (Ti) atom. The N-doped TiO₂ samples illustrated only anatase crystalline phase due to nitrogen dopant in TiO₂ restrained the phase transformation from anatase to rutile. The samples presented the nanorice-like morphology. The expansion on the particle was found at 650 and 700°C of calcination temperature, resulting in increased pore size diameter. The bandgap energy was determined by Kubelka-Munk theory to be in the range 3.07-3.18 eV, which appeared slightly lower than anatase standard (3.20 eV), resulting in the nitrogen dopant could modify the optical absorption edge of TiO₂ from UV to visible light region. The nitrogen content was observed at 100, 300 and 400°C only. Also, the nitrogen element disappeared at 500°C onwards. The nitrogen (N) atom can be incorporated in TiO₂ structure with the interstitial site. The uncalcined (100°C) sample displayed the highest percent paraquat degradation under UV and visible light irradiation due to this sample revealed both the highest specific surface area and nitrogen content level. Moreover, percent paraquat removal significantly decreased with increasing calcination treatment temperature. The nitrogen content level in TiO₂ accelerated the rate of reaction with combining the effect of the specific surface area that generated the electrons and holes during illuminated with light. Therefore, the specific surface area and nitrogen content level demonstrated the important roles in the photocatalytic activity of paraquat under UV and visible light illumination.

Keywords: restraining phase transformation, interstitial site, chemical charge state, photocatalysis, paraquat degradation

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Authors: Emmanuel C. Ngerem

Abstract:

The ever-increasing depletion of the dominant global form of energy (fossil fuels) calls for the development of sustainable and green alternative energy sources such as bioethanol, biohydrogen, and biodiesel. The production of the major biofuels relies on biomass feedstocks that are mainly derived from edible food crops and some inedible plants. One suitable feedstock with great potential as raw material for biofuel production is microalgal biomass. Despite the tremendous attributes of microalgae as a source of biofuel, their cultivation requires huge volumes of freshwater, thus posing a serious threat to commercial-scale production and utilization of algal biomass. In this study, a multi-media wastewater mixture for microalgae growth was formulated and optimized. Moreover, the obtained microalgae biomass was pre-treated to reduce sugar recovery and was compared with previous studies on microalgae biomass pre-treatment. The formulated and optimized mixed wastewater media for biomass and lipid accumulation was established using the simplex lattice mixture design. Based on the superposition approach of the potential results, numerical optimization was conducted, followed by the analysis of biomass concentration and lipid accumulation. The coefficients of regression (R²) of 0.91 and 0.98 were obtained for biomass concentration and lipid accumulation models, respectively. The developed optimization model predicted optimal biomass concentration and lipid accumulation of 1.17 g/L and 0.39 g/g, respectively. It suggested 64.69% dairy wastewater (DWW) and 35.31% paper and pulp wastewater (PWW) mixture for biomass concentration, 34.21% DWW, and 65.79% PWW for lipid accumulation. Experimental validation generated 0.94 g/L and 0.39 g/g of biomass concentration and lipid accumulation, respectively. The obtained microalgae biomass was pre-treated, enzymatically hydrolysed, and subsequently assessed for reducing sugars. The optimization of microwave pre-treatment of Chlorococcum sp. was achieved using response surface methodology (RSM). Microwave power (100 – 700 W), pre-treatment time (1 – 7 min), and acid-liquid ratio (1 – 5%) were selected as independent variables for RSM optimization. The optimum conditions were achieved at microwave power, pre-treatment time, and acid-liquid ratio of 700 W, 7 min, and 32.33:1, respectively. These conditions provided the highest amount of reducing sugars at 10.73 g/L. Process optimization predicted reducing sugar yields of 11.14 g/L on microwave-assisted pre-treatment of 2.52% HCl for 4.06 min at 700 watts. Experimental validation yielded reducing sugars of 15.67 g/L. These findings demonstrate that dairy wastewater and paper and pulp wastewater that could pose a serious environmental nuisance. They could be blended to form a suitable microalgae growth media, consolidating the potency of microalgae as a viable feedstock for fermentable sugars. Also, the outcome of this study supports the microalgal wastewater biorefinery concept, where wastewater remediation is coupled with bioenergy production.

Keywords: wastewater cultivation, mixture design, lipid, biomass, nutrient removal, microwave, Chlorococcum, raceway pond, fermentable sugar, modelling, optimization

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Authors: Evgeniya Orlova, Dmitriy Feoktistov, Geniy Kuznetsov

Abstract:

Spreading of a droplet over a solid substrate is a key phenomenon observed in the following engineering applications: thin film coating, oil extraction, inkjet printing, and spray cooling of heated surfaces. Droplet cooling systems are known to be more effective than film or rivulet cooling systems. It is caused by the greater evaporation surface area of droplets compared with the film of the same mass and wetting surface. And the greater surface area of droplets is connected with the curvature of the interface. Location of the droplets on the cooling surface influences on the heat transfer conditions. The close distance between the droplets provides intensive heat removal, but there is a possibility of their coalescence in the liquid film. The long distance leads to overheating of the local areas of the cooling surface and the occurrence of thermal stresses. To control the location of droplets is possible by changing the roughness, structure and chemical composition of the surface. Thus, control of spreading can be implemented. The most important characteristic of spreading of droplets on solid surfaces is a dynamic contact angle, which is a function of the contact line speed or capillary number. However, there is currently no universal equation, which would describe the relationship between these parameters. This paper presents the results of the experimental studies of water droplet spreading on metal substrates with different surface roughness. The effect of the droplet growth rate and the surface roughness on spreading characteristics was studied at low capillary numbers. The shadow method using high speed video cameras recording up to 10,000 frames per seconds was implemented. A droplet profile was analyzed by Axisymmetric Drop Shape Analyses techniques. According to change of the dynamic contact angle and the contact line speed three sequential spreading stages were observed: rapid increase in the dynamic contact angle; monotonous decrease in the contact angle and the contact line speed; and form of the equilibrium contact angle at constant contact line. At low droplet growth rate, the dynamic contact angle of the droplet spreading on the surfaces with the maximum roughness is found to increase throughout the spreading time. It is due to the fact that the friction force on such surfaces is significantly greater than the inertia force; and the contact line is pinned on microasperities of a relief. At high droplet growth rate the contact angle decreases during the second stage even on the surfaces with the maximum roughness, as in this case, the liquid does not fill the microcavities, and the droplet moves over the “air cushion”, i.e. the interface is a liquid/gas/solid system. Also at such growth rates pulsation of liquid flow was detected; and the droplet oscillates during the spreading. Thus, obtained results allow to conclude that it is possible to control spreading by using the surface roughness and the growth rate of droplets on surfaces as varied factors. Also, the research findings may be used for analyzing heat transfer in rivulet and drop cooling systems of high energy equipment.

Keywords: contact line speed, droplet growth rate, dynamic contact angle, shadow system, spreading

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