Search results for: Metal Organic Frameworks (MOFs)
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5196

Search results for: Metal Organic Frameworks (MOFs)

966 Parenting Interventions for Refugee Families: A Systematic Scoping Review

Authors: Ripudaman S. Minhas, Pardeep K. Benipal, Aisha K. Yousafzai

Abstract:

Background: Children of refugee or asylum-seeking background have multiple, complex needs (e.g. trauma, mental health concerns, separation, relocation, poverty, etc.) that places them at an increased risk for developing learning problems. Families encounter challenges accessing support during resettlement, preventing children from achieving their full developmental potential. There are very few studies in literature that examine the unique parenting challenges refugee families’ face. Providing appropriate support services and educational resources that address these distinctive concerns of refugee parents, will alleviate these challenges allowing for a better developmental outcome for children. Objective: To identify the characteristics of effective parenting interventions that address the unique needs of refugee families. Methods: English-language articles published from 1997 onwards were included if they described or evaluated programmes or interventions for parents of refugee or asylum-seeking background, globally. Data were extracted and analyzed according to Arksey and O’Malley’s descriptive analysis model for scoping reviews. Results: Seven studies met criteria and were included, primarily studying families settled in high-income countries. Refugee parents identified parenting to be a major concern, citing they experienced: alienation/unwelcoming services, language barriers, and lack of familiarity with school and early years services. Services that focused on building the resilience of parents, parent education, or provided services in the family’s native language, and offered families safe spaces to promote parent-child interactions were most successful. Home-visit and family-centered programs showed particular success, minimizing barriers such as transportation and inflexible work schedules, while allowing caregivers to receive feedback from facilitators. The vast majority of studies evaluated programs implementing existing curricula and frameworks. Interventions were designed in a prescriptive manner, without direct participation by family members and not directly addressing accessibility barriers. The studies also did not employ evaluation measures of parenting practices or the caregiving environment, or child development outcomes, primarily focusing on parental perceptions. Conclusion: There is scarce literature describing parenting interventions for refugee families. Successful interventions focused on building parenting resilience and capacity in their native language. To date, there are no studies that employ a participatory approach to program design to tailor content or accessibility, and few that employ parenting, developmental, behavioural, or environmental outcome measures.

Keywords: asylum-seekers, developmental pediatrics, parenting interventions, refugee families

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965 Influence of Cyperus Rotundus Active Principles Inhibit Viral Multiplication and Stimulate Immune System in Indian White Shrimp Fenneropenaeus Indicus against White Spot Syndrome Virus Infection

Authors: Thavasimuthu Citarasu, Mariavincent Michaelbabu, Vikram Vakharia

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The rhizome of Java grass, Cyperus rotundus was extracted different organic polar and non-polar solvents and performed the in vitro antiviral and immunostimulant activities against White Spot Syndrome Virus (WSSV) and Vibrio harveyi respectively. Based on the initial screening the ethyl acetate extract of C. rotundus was strong activities and further it was purified through silica column chromatography and the fractions were screened again for antiviral and immunostimulant activity. Among the different fractions screened against the WSSV and V. harveyi, the fractions, F-III to FV had strong activities. In order to study the in vivo influence of C. rotundus, the fractions (F-III to FV) were pooled and delivered to the F. indicus through artificial feed for 30 days. After the feeding trail the experimental and control diet fed F. indicus were challenged with virulent WSSV and studied the survival, molecular diagnosis, biochemical, haematological and immunological parameters. Surprisingly, the pooled fractions (F-III to FV) incorporated diets helped to significantly (P < 0.01) suppressed viral multiplication, showed significant (P < 0.01) differences in protein and glucose levels, improved total haemocyte count (THC), coagulase activity, significantly increased (P < =0.001) prophenol oxidase and intracellular superoxide anion production compared to the control shrimps. Based on the results, C. rotundus extracts effectively suppressed WSSV multiplication and improve the immune system in F. indicus against WSSV infection and this knowledge will helps to develop novel drugs from C. rotundus against WSSV.

Keywords: antiviral drugs, cyperus rotundus, fenneropenaeus indicus, WSSV

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964 Effects of Seed Culture and Attached Growth System on the Performance of Anammox Hybrid Reactor (AHR) Treating Nitrogenous Wastewater

Authors: Swati Tomar, Sunil Kumar Gupta

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The start-up of anammox (anaerobic ammonium oxidation) process in hybrid reactor delineated four distinct phases i.e. cell lysis, lag phase, activity elevation and stationary phase. Cell lysis phase was marked by death and decay of heterotrophic denitrifiers resulting in breakdown of organic nitrogen into ammonium. Lag phase showed initiation of anammox activity with turnover of heterotrophic denitrifiers, which is evident from appearance of NO3-N in the effluent. In activity elevation phase, anammox became the dominant reaction, which can be attributed to consequent reduction of NH4-N into N2 with increased NO3-N in the effluent. Proper selection of mixed seed culture at influent NO2-/NH4+ ratio (1:1) and hydraulic retention time (HRT) of 1 day led to early startup of anammox within 70 days. Pseudo steady state removal efficiencies of NH4+ and NO2- were found as 94.3% and 96.4% respectively, at nitrogen loading rate (NLR) of 0.35 kg N/m3d at an HRT of 1 day. Analysis of the data indicated that attached growth system contributes an additional 11% increase in the ammonium removal and results in an average of 29% reduction in sludge washout rate. Mass balance study of nitrogen indicated that 74.1% of total input nitrogen is converted into N2 gas followed by 11.2% being utilized in biomass development. Scanning electron microscope (SEM) observation of the granular sludge clearly showed the presence of cocci and rod shaped microorganisms intermingled on the external surface of the granules. The average size of anammox granules (1.2-1.5 mm) with an average settling velocity of 45.6 m/h indicated a high degree of granulation resulting into formation of well compacted granules in the anammox process.

Keywords: anammox, hybrid reactor, startup, granulation, nitrogen removal, mixed seed culture

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963 Theorizing Optimal Use of Numbers and Anecdotes: The Science of Storytelling in Newsrooms

Authors: Hai L. Tran

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When covering events and issues, the news media often employ both personal accounts as well as facts and figures. However, the process of using numbers and narratives in the newsroom is mostly operated through trial and error. There is a demonstrated need for the news industry to better understand the specific effects of storytelling and data-driven reporting on the audience as well as explanatory factors driving such effects. In the academic world, anecdotal evidence and statistical evidence have been studied in a mutually exclusive manner. Existing research tends to treat pertinent effects as though the use of one form precludes the other and as if a tradeoff is required. Meanwhile, narratives and statistical facts are often combined in various communication contexts, especially in news presentations. There is value in reconceptualizing and theorizing about both relative and collective impacts of numbers and narratives as well as the mechanism underlying such effects. The current undertaking seeks to link theory to practice by providing a complete picture of how and why people are influenced by information conveyed through quantitative and qualitative accounts. Specifically, the cognitive-experiential theory is invoked to argue that humans employ two distinct systems to process information. The rational system requires the processing of logical evidence effortful analytical cognitions, which are affect-free. Meanwhile, the experiential system is intuitive, rapid, automatic, and holistic, thereby demanding minimum cognitive resources and relating to the experience of affect. In certain situations, one system might dominate the other, but rational and experiential modes of processing operations in parallel and at the same time. As such, anecdotes and quantified facts impact audience response differently and a combination of data and narratives is more effective than either form of evidence. In addition, the present study identifies several media variables and human factors driving the effects of statistics and anecdotes. An integrative model is proposed to explain how message characteristics (modality, vividness, salience, congruency, position) and individual differences (involvement, numeracy skills, cognitive resources, cultural orientation) impact selective exposure, which in turn activates pertinent modes of processing, and thereby induces corresponding responses. The present study represents a step toward bridging theoretical frameworks from various disciplines to better understand the specific effects and the conditions under which the use of anecdotal evidence and/or statistical evidence enhances or undermines information processing. In addition to theoretical contributions, this research helps inform news professionals about the benefits and pitfalls of incorporating quantitative and qualitative accounts in reporting. It proposes a typology of possible scenarios and appropriate strategies for journalists to use when presenting news with anecdotes and numbers.

Keywords: data, narrative, number, anecdote, storytelling, news

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962 ZnO Nanoparticles as Photocatalysts: Synthesis, Characterization and Application

Authors: Pachari Chuenta, Suwat Nanan

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ZnO nanostructures have been synthesized successfully in high yield via catalyst-free chemical precipitation technique by varying zinc source (either zinc nitrate or zinc acetate) and oxygen source (either oxalic acid or urea) without using any surfactant, organic solvent or capping agent. The ZnO nanostructures were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), UV-vis diffuse reflection spectroscopy (UV-vis DRS), and photoluminescence spectroscopy (PL). The FTIR peak in the range of 450-470 cm-1 corresponded to Zn-O stretching in ZnO structure. The synthesized ZnO samples showed well crystalized hexagonal wurtzite structure. SEM micrographs displayed spherical droplet of about 50-100 nm. The band gap of prepared ZnO was found to be 3.4-3.5 eV. The presence of PL peak at 468 nm was attributed to surface defect state. The photocatalytic activity of ZnO was studied by monitoring the photodegradation of reactive red (RR141) azo dye under ultraviolet (UV) light irradiation. Blank experiment was also separately carried out by irradiating the aqueous solution of the dye in absence of the photocatalyst. The initial concentration of the dye was fixed at 10 mgL-1. About 50 mg of ZnO photocatalyst was dispersed in 200 mL dye solution. The sample was collected at a regular time interval during the irradiation and then was analyzed after centrifugation. The concentration of the dye was determined by monitoring the absorbance at its maximum wavelength (λₘₐₓ) of 544 nm using UV-vis spectroscopic analysis technique. The sources of Zn and O played an important role on photocatalytic performance of the ZnO photocatalyst. ZnO nanoparticles which prepared by zinc acetate and oxalic acid at molar ratio of 1:1 showed high photocatalytic performance of about 97% toward photodegradation of reactive red azo dye (RR141) under UV light irradiation for only 60 min. This work demonstrates the promising potential of ZnO nanomaterials as photocatalysts for environmental remediation.

Keywords: azo dye, chemical precipitation, photocatalytic, ZnO

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961 Heavy Metal Contamination of a Dumpsite Environment as Assessed with Pollution Indices

Authors: Olubunmi S. Shittu, Olufemi J. Ayodele, Augustus O. A. Ilori, Abidemi O. Filani, Adetola T. Afuye

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Indiscriminate refuse dumping in and around Ado-Ekiti combined with improper management of few available dumpsites, such as Ilokun dumpsite, posed the threat of heavy metals pollution in the surrounding soils and underground water that needs assessment using pollution indices. Surface soils (0-15 cm) were taken from the centre of Ilokun dumpsite (0 m) and environs at different directions and distances during the dry and wet seasons, as well as a background sample at 1000 m away, adjacent to the dumpsite at Ilokun, Ado-Ekiti, Nigeria. The concentration of heavy metals used to calculate the pollution indices for the soils were determined using Atomic Adsorption Spectrophotometer. The soils recorded high concentrations of all the heavy metals above the background concentrations irrespective of the season with highest concentrations at the 0 m except Ni and Fe at 50 m during the dry and wet season, respectively. The heavy metals concentration were in the order of Ni > Mn > Pb > Cr > Cu > Cd > Fe during the dry season, and Fe > Cr > Cu > Pb > Ni > Cd > Mn during the wet season. Using the Contamination Factor (CF), the soils were classified to be moderately contaminated with Cd and Fe to very high contamination with other metals during the dry season and low Cd contamination (0.87), moderate contamination with Fe, Pb, Mn and Ni and very high contamination with Cr and Cu during the wet season. At both seasons, the Pollution Load Index (PLI) indicates the soils to be generally polluted with heavy metals and the Geoaccumulation Index (Igeo) calculated shown the soils to be in unpolluted to moderately polluted levels. Enrichment Factor (EF) implied the soils to be deficiently enriched with all the heavy metals except Cr (7.90) and Cu (6.42) that were at significantly enrichment levels during the wet season. Modified Degree of Contamination (mCd) recorded, indicated the soils to be of very high to extremely high degree of contamination during the dry season and moderate degree of contamination during the wet season except 0 m with high degree of contamination. The concentration of heavy metals in the soils combined with some of the pollution indices indicated the soils in and around the Ilokun Dumpsite are being polluted with heavy metals from anthropogenic sources constituted by the indiscriminate refuse dumping.

Keywords: contamination factor, enrichment factor, geoaccumulation index, modified degree of contamination, pollution load index

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960 Effect of Sodium Hydroxide Treatment on the Mechanical Properties of Crushed and Uncrushed Luffa cylindrica Fibre Reinforced rLDPE Composites

Authors: Paschal A. Ubi, Salawu Abdul Rahman Asipita

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The use of suitable engineering materials which poses less harm to ,an and the environment is sort for in recent times, thus giving rise to polymer composites filled with natural organic reinforcement which are biodegradable. Treatment of natural fibres is essential in improving matrix to filler adhesion, hence improving its mechanical properties. In this study, investigations were carried out to determine the effect of sodium hydroxide treatment on the tensile, flexural, impact and hardness properties of crushed and uncrushed luffa cylindrica fibre reinforced recycled low density polyethylene composites. The LC (Luffa Cylindrica) fibres were treated with 0%, 2%, 4%, 6%, 8%, and 10% wt. NaOH concentrations for a period of 24 hours under room temperature conditions. The compounding of the waste LDPE was done using a two roll mill at a temperature of 150 oC and cured in a hydraulic press at a temperature of 150oC for 3 minutes at 3 metric tonnes. A formulation of 20/80g (reinforcement to matrix ratio in grams) was maintained for all fabricated samples. Analysis of the results showed that the uncrushed luffa fibre samples gave better mechanical properties compared with the crushed luffa fibre samples. The uncrushed luffa fibre composites had optimum tensile and flexural strengths of 7.65MPa and 17.08Mpa respectively corresponding to a young modulus and flexural modulus of 21.08MPa and 232.22MPa for the 8% and 4%wt. NaOH concentration respectively. Results obtained in the research showed that NaOH treatment with the 8% NaOH concentration improves the mechanical properties of the LC fibre reinforced composites when compared with other NaOH treatment concentration values.

Keywords: LC fibres, NaOH concentration, LC/rLDPE composite, tensile strength, flexural strength

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959 Biologically Synthesised Silver Nanoparticles Induces Autophagy and JNK Signaling as a Pro-Survival Response by Abrogating Reactive Oxygen Species Accumulation in Cancer Cells

Authors: Sudeshna Mukherjee, Leena Fageria, R. Venkataramana Dilip, Rajdeep Chowdhury, Jitendra Panwar

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Metal nanoparticles in recent years have gained importance in cancer therapy due to their enhanced permeability retention effect. Among various nanomaterials, silver nanoparticles (AgNPs) have received considerable attention due to their unique properties like conductivity, chemical stability, relative lower toxicity and outstanding therapeutic potential, such as anti-inflammatory, antimicrobial and anti-cancerous activities. In this study, we took a greener approach to synthesize silver nanoparticle from fungus and analyze its effects on both epithelial and mesenchymal derived cancer cells. Much research has been done on nanoparticle-induced apoptosis, but little is known about its role in autophagy. In our study, the silver nanoparticles were seen to induce autophagy which was analyzed by studying the expression of several autophagy markers like, LC3B-II and ATG genes. Monodansylcadaverine (MDC) assay also revealed the induction of autophagy upon treatment with AgNPs. Inhibition of autophagy by chloroquine resulted in increased cell death suggesting autophagy as a survival strategy adopted by the cells. In parallel to autophagy induction, silver nanoparticles induced ROS accumulation. Interestingly, autophagy inhibition by chloroquine increased ROS level, resulting in enhanced cell death. We further analyzed MAPK signaling upon AgNP treatment. It was observed that along with autophagy, activation of JNK signaling served as pro-survival while ERK signaling served as a pro-death signal. Our results provide valuable insights into the role of autophagy upon AgNP exposure and provide cues to probabilistic strategies to effectively sensitize cancer cells.

Keywords: autophagy, JNK signalling, reactive oxygen species, silver nanoparticles

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958 Microbial Electrochemical Remediation System: Integrating Wastewater Treatment with Simultaneous Power Generation

Authors: Monika Sogani, Zainab Syed, Adrian C. Fisher

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Pollution of estrogenic compounds has caught the attention of researchers as the slight increase of estrogens in the water bodies has a significant impact on the aquatic system. They belong to a class of endocrine disrupting compounds (EDCs) and are able to mimic hormones or interfere with the action of endogenous hormones. The microbial electrochemical remediation system (MERS) is employed here for exploiting an electrophototrophic bacterium for evaluating the capacity of biodegradation of ethinylestradiol hormone (EE2) under anaerobic conditions with power generation. MERS using electro-phototrophic bacterium offers a tailored solution of wastewater treatment in a developing country like India which has a huge solar potential. It is a clean energy generating technology as they require only sunlight, water, nutrients, and carbon dioxide to operate. Its main feature that makes it superior over other technologies is that the main fuel for this MERS is sunlight which is indefinitely present. When grown in light with organic compounds, these photosynthetic bacteria generate ATP by cyclic photophosphorylation and use carbon compounds to make cell biomass (photoheterotrophic growth). These cells showed EE2 degradation and were able to generate hydrogen as part of the process of nitrogen fixation. The two designs of MERS were studied, and a maximum of 88.45% decrease in EE2 was seen in a total period of 14 days in the better design. This research provides a better insight into microbial electricity generation and self-sustaining wastewater treatment facilities. Such new models of waste treatment aiming waste to energy generation needs to be followed and implemented for building a resource efficient and sustainable economy.

Keywords: endocrine disrupting compounds, ethinylestradiol, microbial electrochemical remediation systems, wastewater treatment

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957 Technology in Commercial Law Enforcement: Tanzania, Canada, and Singapore Comparatively

Authors: Katarina Revocati Mteule

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The background of this research arises from global demands for fair business opportunities. As one of responses to these demands, nations embarked on reforms in commercial laws. In 1990s Tanzania resorted to economic transformation through liberalization to attract more investments included reform in commercial laws enforcement. This research scrutinizes the effectiveness of reforms in Tanzania in comparison with Canada and Singapore and the role of technology. The methodology to be used is doctrinal legal research mixed with international comparative legal research. It involves comparative analysis of library, online, and internet resources as well as Case Laws and Statutory Laws. Tanzania, Canada and Singapore are sampled comparators basing on their distinct level of economic development. The criteria of analysis includes the nature of reforms, type of technology, technological infrastructure and human resource technical competence in each country. As the world progresses towards reforms in commercial laws, improvements in law, policy, and regulatory frameworks are paramount. Specifically, commercial laws are essential in contract enforcement and dispute resolution and how it copes with modern technologies is a concern. Harnessing the best technology is necessary to cope with the modernity in world businesses. In line with this, Tanzania is improving its business environment, including law enforcement mechanisms that are supportive to investments. Reforms such as specialized commercial law enforcement coupled with alternative dispute resolutions such as arbitration, mediation, and reconciliation are emphasized. Court technology as one of the reform tools given high priority. This research evaluates the progress and the effectiveness of the reforms in Commercial Laws towards friendly business environment in Tanzania in comparison with Canada and Singapore. The experience of Tanzania is compared with Canada and Singapore to see what to improve for each country to enhance quick and fair enforcement of commercial law. The research proposes necessary global standards of procedures and in national laws to offer a business-friendly environment and the use of appropriate technology. Solutions are proposed in tackling the challenges of delays in enforcing Commercial Laws such as case management, funding, legal and procedural hindrances, laxity among staff, and abuse of Court process among litigants, all in line with modern technology. It is the finding of the research that proper use of technology has managed to reduce case backlogs and time taken to resolve a commercial dispute, to increase court integrity by minimizing human contacts in commercial law enforcement which may lead to solicitation of favors and saving of parties’ time due to online service. Among the three countries, each one is facing a distinct challenge due to the level of poverty and remoteness from online service. How solutions are found in one country is a lesson to another. To conclude, this paper is suggesting solutions for improving the commercial law enforcement mechanisms in line with modern technology. The call for technological transformation is essential for the enforcement of commercial laws.

Keywords: commercial law, enforcement, technology

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956 J-Integral Method for Assessment of Structural Integrity of a Pressure Vessel

Authors: Karthik K. R, Viswanath V, Asraff A. K

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The first stage of a new-generation launch vehicle of ISRO makes use of large pressure vessels made of Aluminium alloy AA2219 to store fuel and oxidizer. These vessels have many weld joints that may contain cracks or crack-like defects during their fabrication. These defects may propagate across the vessel during pressure testing or while in service under the influence of tensile stresses leading to catastrophe. Though ductile materials exhibit significant stable crack growth prior to failure, it is not generally acceptable for an aerospace component. There is a need to predict the initiation of stable crack growth. The structural integrity of the vessel from fracture considerations can be studied by constructing the Failure Assessment Diagram (FAD) that accounts for both brittle fracture and plastic collapse. Critical crack sizes of the pressure vessel may be highly conservative if it is predicted from FAD alone. If the J-R curve for material under consideration is available apriori, the critical crack sizes can be predicted to a certain degree of accuracy. In this paper, a novel approach is proposed to predict the integrity of a weld in a pressure vessel made of AA2219 material. Fracture parameter ‘J-integral’ at the crack front, evaluated through finite element analyses, is used in the new procedure. Based on the simulation of tension tests carried out on SCT specimens by NASA, a cut-off value of J-integral value (J?ᵤₜ_ₒ??) is finalised. For the pressure vessel, J-integral at the crack front is evaluated through FE simulations incorporating different surface cracks at long seam weld in a cylinder and in dome petal welds. The obtained J-integral, at vessel level, is compared with a value of J?ᵤₜ_ₒ??, and the integrity of vessel weld in the presence of the surface crack is firmed up. The advantage of this methodology is that if SCT test data of any metal is available, the critical crack size in hardware fabricated using that material can be predicted to a better level of accuracy.

Keywords: FAD, j-integral, fracture, surface crack

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955 Viscoelastic Properties of Sn-15%Pb Measured in an Oscillation Test

Authors: Gerardo Sanjuan Sanjuan, Ángel Enrique Chavéz Castellanos

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The knowledge of the rheological behavior of partially solidified metal alloy is an important issue when modeling and simulation of die filling in semisolid processes. Many experiments for like steady state, the step change in shear rate tests, shear stress ramps have been carried out leading that semi-solid alloys exhibit shear thinning, thixotropic behavior and yield stress. More advanced investigation gives evidence some viscoelastic features can be observed. The viscoelastic properties of materials are determinate by transient or dynamic methods; unfortunately, sparse information exists about oscillation experiments. The aim of this present work is to use small amplitude oscillatory tests for knowledge properties such as G´ and G´´. These properties allow providing information about materials structure. For this purpose, we investigated tin-lead alloy (Sn-15%Pb) which exhibits a similar microstructure to aluminum alloys and is the classic alloy for semisolid thixotropic studies. The experiments were performed with parallel plates rheometer AR-G2. Initially, the liquid alloy is cooled down to the semisolid range, a specific temperature to guarantee a constant fraction solid. Oscillation was performed within the linear viscoelastic regime with a strain sweep. So, the loss modulus G´´, the storage modulus G´ and the loss angle (δ) was monitored. In addition a frequency sweep at a strain below the critical strain for characterized its structure. This provides more information about the interactions among solid particles on a liquid matrix. After testing, the sample was removed then cooled, sectioned and examined metallographically. These experiments demonstrate that the viscoelasticity is sensitive to the solid fraction, and is strongly influenced by the shape and size of particles solid.

Keywords: rheology, semisolid alloys, thixotropic, viscoelasticity

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954 Quantum Dot – DNA Conjugates for Biological Applications

Authors: A. Banerjee, C. Grazon, B. Nadal, T. Pons, Y. Krishnan, B. Dubertret

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Quantum Dots (QDs) have emerged as novel fluorescent probes for biomedical applications. The photophysical properties of QDs such as broad absorption, narrow emission spectrum, reduced blinking, and enhanced photostability make them advantageous over organic fluorophores. However, for some biological applications, QDs need to be first targeted to specific intracellular locations. It parallel, base pairing properties and biocompatibility of DNA has been extensively used for biosensing, targetting and intracellular delivery of numerous bioactive agents. The combination of the photophysical properties of QDs and targettability of DNA has yielded fluorescent, stable and targetable nanosensors. QD-DNA conjugates have used in drug delivery, siRNA, intracellular pH sensing and several other applications; and continue to be an active area of research. In this project, a novel method to synthesise QD-DNA conjugates and their applications in bioimaging are investigated. QDs are first solubilized in water using a thiol based amphiphilic co-polymer and, then conjugated to amine functionalized DNA using a heterobifunctional linker. The conjugates are purified by size exclusion chromatography and characterized by UV-Vis absorption and fluorescence spectroscopy, electrophoresis and microscopy. Parameters that influence the conjugation yield such as reducing agents, the excess of salt and pH have been investigated in detail. In optimized reaction conditions, up to 12 single-stranded DNA (15 mer length) can be conjugated per QD. After conjugation, the QDs retain their colloidal stability and high quantum yield; and the DNA is available for hybridization. The reaction has also been successfully tested on QDs emitting different colors and on Gold nanoparticles and therefore highly generalizable. After extensive characterization and robust synthesis of QD-DNA conjugates in vitro, the physical properties of these conjugates in cellular milieu are being invistigated. Modification of QD surface with DNA appears to remarkably alter the fate of QD inside cells and can have potential implications in therapeutic applications.

Keywords: bioimaging, cellular targeting, drug delivery, photostability

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953 Cadmium Levels in Patients with Type 2 Diabetes Mellitus in Thasala Southern Thailand

Authors: Supabhorn Yimthiang, Wiyada Khanwian

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Cadmium is a heavy metal that is important in the environment because it is highly toxic. The incidence and severity of type 2 diabetes mellitus are known to be associated with cadmium. The purpose of this study was to investigate the cadmium levels in patients with type 2 diabetes mellitus at diabetes mellitus clinic, Thasala hospital, Nakhon Si Thummarat, Thailand. The study population was composed of forty five subjects. Among them, twenty two were diabetic patients and twenty three were apparently healthy non-diabetic individual subjects. After an overnight fasting, blood and morning urine samples were collected from each subject to determine fasting blood sugar and cadmium levels in urine, respectively. Systolic and diastolic blood pressure values were measured by aneroid sphygmomanometer. Study approval was taken from the human subject ethics committee of Walailak University. Verbal and written informed consent was taken from all participants. In the study samples, there were 31.8% males and 68.2% females with mean age of 47+10.53 years. The geometric mean of urine cadmium was significantly higher in diabetic patients (1.015 + 0.79 µg/g creatinine) when compared with the healthy subjects (0.395 + 0.53 µg/g creatinine) (P<0.05). This result also showed that urine cadmium excretion in diabetic patients was higher than in healthy subjects by 2.6 times. Moreover, fasting blood sugar (153+47.86 μg/dl) and systolic blood pressure (183.26+17.15 mmHg) of diabetic patients was significantly different when compared with healthy subjects (79+5.38 μg/dl and 112.78+11.32 mmHg, respectively) (P<0.05). Meanwhile, the concentration of cadmium in urine showed positive correlation with fasting plasma glucose (r=0.616) and systolic blood pressure (r=0.487). This preliminary study showed that cadmium might play an important role in the development and pathogenesis of diabetes mellitus in general population. However, these findings require confirmation through additional epidemiological and biological research.

Keywords: blood pressure, cadmium, fasting blood sugar, type 2 diabetes mellitus

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952 Promoting Personhood and Citizenship Amongst Individuals with Learning Disabilities: An Occupational Therapy Approach

Authors: Rebecca Haythorne

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Background: Agendas continuously emphasise the need to increase work based training and opportunities for individuals with learning disabilities. However research and statistics suggest that there is still significant stigma and stereotypes as to what they can contribute, or gain from being part of the working environment. Method: To tackles some of these prejudices an Occupational Therapy based intervention was developed for learning disability service users working at a social enterprise farm. The intervention aimed to increase positive public perception around individual capabilities and encourage individuals with learning disabilities to take ownership and be proud of their individual personhood and citizenship. This was achieved by using components of the Model of Human Occupation to tailor the intervention to individual values, skills and working contributions. The final project involved making creative wall art for public viewing, focusing on 'who works there and what they do'. This was accompanied by a visitor information guide, allowing individuals to tell visitors about themselves, the work they do and why it is meaningful to them. Outcomes: The intervention has helped to increased metal well-being and confidence of learning disability service users “people will know I work here now” and “I now have something to show my family about the work I do at the farm”. The intervention has also increased positive public perception and community awareness “you can really see the effort that’s gone into doing this” and “it’s a really visual experience to see people you don’t expect to see doing this type of work”. Resources left behind have further supported individuals to take ownership in creating more wall art to be sold at the farm shop. Conclusion: the intervention developed has helped to improve mental well-being of both service users and staff and improve community awareness. Due to this, the farm has decided to roll out the intervention to other areas of the social enterprise and is considering having more Occupational Therapy involvement in the future.

Keywords: citizenship, intervention, occupational therapy, personhood

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951 Perceived Impact of Climate Change on the Livelihood of Arable Crop Farmers in Ipokia Local Government Area of Ogun State, Nigeria

Authors: Emmanuel Olugbenga Fakoya

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The study examined the perceived impact of climate change on the livelihood of arable crop farmers in Ipokia Local Government Area of Ogun State, Nigeria. Multistage sampling technique was used to select 80 arable crop farmers in the study area. Data collected were analyzed using percentages, frequencies and Chi square analysis. The result showed that 63.8 percent of the respondents were male while 55.0 percent were married. Less than half (30.0 percent) of the respondents were between the age bracket of 41-50 years and 50.0 percent had 6-10 household size. Furthermore, majority (40.0 percent) of the arable crop farmers farmed on an inherited land and 51.3 percent had 2-3 hectares of land. Majority (38.8 percent) of the farmers intercrop maize with cassava and maize with yam. Various strategies adapted to reduce the effect of climate change on their crop and livelihood include: crop rotation (53.8 percent), planting of leguminous crop (35.0 percent), application of organic fertilizers (45.0 percent), mulching (56.3 percent) and by planting drought resistance crops (46.5 percent). Reported among the effects of climate change on crop and farmers’ livelihood were: discoloration of crop leave (63.8 percent), increase infestation of pests and diseases (58.8 percent) and reduction of crop yield (60.0 percent). Chi- square analysis showed significant relationship between impact of climate change on arable crop production and thus famers’ livelihood. It was concluded from the study that climate change is an impinging factor that seriously affect arable crop production and hence farmers’ livelihood despite coping strategies to minimize its effect. It was however recommended that Agricultural policies and practices that could minimize or eliminate its effect should be seriously enacted to boost production and increase farmers’ livelihood.

Keywords: agricultural extension, extension agent, private sector, perception

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950 Comparison of Various Landfill Ground Improvement Techniques for Redevelopment of Closed Landfills to Cater Transport Infrastructure

Authors: Michael D. Vinod, Hadi Khabbaz

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Construction of infrastructure above or adjacent to landfills is becoming more common to capitalize on the limited space available within urban areas. However, development above landfills is a challenging task due to large voids, the presence of organic matter, heterogeneous nature of waste and ambiguity surrounding landfill settlement prediction. Prior to construction of infrastructure above landfills, ground improvement techniques are being employed to improve the geotechnical properties of landfill material. Although the ground improvement techniques have little impact on long term biodegradation and creep related landfill settlement, they have shown some notable short term success with a variety of techniques, including methods for verifying the level of effectiveness of ground improvement techniques. This paper provides geotechnical and landfill engineers a guideline for selection of landfill ground improvement techniques and their suitability to project-specific sites. Ground improvement methods assessed and compared in this paper include concrete injected columns (CIC), dynamic compaction, rapid impact compaction (RIC), preloading, high energy impact compaction (HEIC), vibro compaction, vibro replacement, chemical stabilization and the inclusion of geosynthetics such as geocells. For each ground improvement technique a summary of the existing theory, benefits, limitations, suitable modern ground improvement monitoring methods, the applicability of ground improvement techniques for landfills and supporting case studies are provided. The authors highlight the importance of implementing cost-effective monitoring techniques to allow observation and necessary remediation of the subsidence effects associated with long term landfill settlement. These ground improvement techniques are primarily for the purpose of construction above closed landfills to cater for transport infrastructure loading.

Keywords: closed landfills, ground improvement, monitoring, settlement, transport infrastructure

Procedia PDF Downloads 215
949 Highly Efficient Ca-Doped CuS Counter Electrodes for Quantum Dot Sensitized Solar Cells

Authors: Mohammed Panthakkal Abdul Muthalif, Shanmugasundaram Kanagaraj, Jumi Park, Hangyu Park, Youngson Choe

Abstract:

The present study reports the incorporation of calcium ions into the CuS counter electrodes (CEs) in order to modify the photovoltaic performance of quantum dot-sensitized solar cells (QDSSCs). Metal ion-doped CuS thin film was prepared by the chemical bath deposition (CBD) method on FTO substrate and used directly as counter electrodes for TiO₂/CdS/CdSe/ZnS photoanodes based QDSSCs. For the Ca-doped CuS thin films, copper nitrate and thioacetamide were used as anionic and cationic precursors. Calcium nitrate tetrahydrate was used as doping material. The surface morphology of Ca-doped CuS CEs indicates that the fragments are uniformly distributed, and the structure is densely packed with high crystallinity. The changes observed in the diffraction patterns suggest that Ca dopant can introduce increased disorder into CuS material structure. EDX analysis was employed to determine the elemental identification, and the results confirmed the presence of Cu, S, and Ca on the FTO glass substrate. The photovoltaic current density – voltage characteristics of Ca-doped CuS CEs shows the specific improvements in open circuit voltage decay (Voc) and short-circuit current density (Jsc). Electrochemical impedance spectroscopy results display that Ca-doped CuS CEs have greater electrocatalytic activity and charge transport capacity than bare CuS. All the experimental results indicate that 20% Ca-doped CuS CE based QDSSCs exhibit high power conversion efficiency (η) of 4.92%, short circuit current density of 15.47 mA cm⁻², open circuit photovoltage of 0.611 V, and fill factor (FF) of 0.521 under illumination of one sun.

Keywords: Ca-doped CuS counter electrodes, surface morphology, chemical bath deposition method, electrocatalytic activity

Procedia PDF Downloads 161
948 Effect of Microstructure on Wear Resistance of Polycrystalline Diamond Composite Cutter of Bit

Authors: Fanyuan Shao, Wei Liu, Deli Gao

Abstract:

Polycrystalline diamond composite (PDC) cutter is made of diamond powder as raw material, cobalt metal or non-metallic elements as a binder, mixed with WC cemented carbide matrix assembly, through high temperature and high-pressure sintering. PDC bits with PDC cutters are widely used in oil and gas drilling because of their high hardness, good wear resistance and excellent impact toughness. And PDC cutter is the main cutting tool of bit, which seriously affects the service of the PDC bit. The wear resistance of the PDC cutter is measured by cutting granite with a vertical turret lathe (VTL). This experiment can achieve long-distance cutting to obtain the relationship between the wear resistance of the PDC cutter and cutting distance, which is more closely to the real drilling situation. Load cell and 3D optical profiler were used to obtain the value of cutting forces and wear area, respectively, which can also characterize the damage and wear of the PDC cutter. PDC cutters were cut via electrical discharge machining (EDM) and then flattened and polished. A scanning electron microscope (SEM) was used to observe the distribution of binder cobalt and the size of diamond particles in a diamond PDC cutter. The cutting experimental results show that the wear area of the PDC cutter has a good linear relationship with the cutting distance. Simultaneously, the larger the wear area is and the greater the cutting forces are required to maintain the same cutting state. The size and distribution of diamond particles in the polycrystalline diamond layer have a great influence on the wear resistance of the diamond layer. And PDC cutter with fine diamond grains shows more wear resistance than that with coarse grains. The deep leaching process is helpful to reduce the effect of binder cobalt on the wear resistance of the polycrystalline diamond layer. The experimental study can provide an important basis for the application of PDC cutters in oil and gas drilling.

Keywords: polycrystalline diamond compact, scanning electron microscope, wear resistance, cutting distance

Procedia PDF Downloads 193
947 Environmental Degradation of Natural Resources in Broghil National Park in the High Mountains of Pakistan – Empirical Evidence From Local Community and Geoinformatics

Authors: Siddique Ullah Baig, Alisha Manzoor

Abstract:

The remotest, mountainous, and icy Broghil Valley is a high-profile protected area as a national park, which hosts one of the highest altitude permanent human settlements on the earth. This park hosts a distributed but diverse range of habitats. Due to a lack of infrastructures, higher altitudes, and harsh environmental conditions, poverty-stricken inhabitants mostly rely on its resources, causing ecological dis-balance. This study aims to investigate the environmental degradation of natural resources of the park based on empirical evidence from stakeholders and geoinformatics. The result shows that one-fourth of the park is a gently undulating basin dotted with water bodies / grass, and agricultural land and three fourth is entirely rugged with steep mountains and glaciers. There are virtually no forests as the arid cold tundra climate and high altitude prevent tree growth. Rapid three-decadal land cover changes have led to ecological disequilibrium of the park, narrowing the traditional diverse food base, decreasing the resilience of biodiversity and local livelihoods as crop-land has shifted towards fallow, alpine-grass to peat-land and snow/glacial ice area to bare-soil/rocks. The local community believes in exploiting whatever vegetation or organic material is available for use as food, fodder, and fuel. The permanent presence of the community and limited cost-effective options in the park will be a challenge forever to maintain undisturbed natural processes as the objective of a national park.

Keywords: Broghil National Park, natural resources, environmental degradation, land cover

Procedia PDF Downloads 61
946 Closing the Loop between Building Sustainability and Stakeholder Engagement: Case Study of an Australian University

Authors: Karishma Kashyap, Subha D. Parida

Abstract:

Rapid population growth and urbanization is creating pressure throughout the world. This has a dramatic effect on a lot of elements which include water, food, transportation, energy, infrastructure etc. as few of the key services. Built environment sector is growing concurrently to meet the needs of urbanization. Due to such large scale development of buildings, there is a need for them to be monitored and managed efficiently. Along with appropriate management, climate adaptation is highly crucial as well because buildings are one of the major sources of greenhouse gas emission in their operation phase. Buildings to be adaptive need to provide a triple bottom approach to sustainability i.e., being socially, environmentally and economically sustainable. Hence, in order to deliver these sustainability outcomes, there is a growing understanding and thrive towards switching to green buildings or renovating new ones as per green standards wherever possible. Academic institutions in particular have been following this trend globally. This is highly significant as universities usually have high occupancy rates because they manage a large building portfolio. Also, as universities accommodate the future generation of architects, policy makers etc., they have the potential of setting themselves as a best industry practice model for research and innovation for the rest to follow. Hence their climate adaptation, sustainable growth and performance management becomes highly crucial in order to provide the best services to users. With the objective of evaluating appropriate management mechanisms within academic institutions, a feasibility study was carried out in a recent 5-Star Green Star rated university building (housing the School of Construction) in Victoria (south-eastern state of Australia). The key aim was to understand the behavioral and social aspect of the building users, management and the impact of their relationship on overall building sustainability. A survey was used to understand the building occupant’s response and reactions in terms of their work environment and management. A report was generated based on the survey results complemented with utility and performance data which were then used to evaluate the management structure of the university. Followed by the report, interviews were scheduled with the facility and asset managers in order to understand the approach they use to manage the different buildings in their university campuses (old, new, refurbished), respective building and parameters incorporated in maintaining the Green Star performance. The results aimed at closing the communication and feedback loop within the respective institutions and assist the facility managers to deliver appropriate stakeholder engagement. For the wider design community, analysis of the data highlights the applicability and significance of prioritizing key stakeholders, integrating desired engagement policies within an institution’s management structures and frameworks and their effect on building performance

Keywords: building optimization, green building, post occupancy evaluation, stakeholder engagement

Procedia PDF Downloads 352
945 Antimicrobial, Antioxidant Activities and Phytochemical Screening of Five Species from Acacia Used in Sudanese Ethnomedicine

Authors: Hajir Abdllha, Alaa Mohamed, Khansa Almoniem, Naga Adam, Wdeea Alhaadi, Ahmed Elshikh, Ahmed Ali, Ismail Makuar, Anas Elnazeer, Nagat Elrofaei, Samir Abdoelftah, Monier Hemidan

Abstract:

The present study was designed to investigate antimicrobial, and antioxidant activities of five species from Acacia (Acacia albidia, Acacia mellifera, Acacia nubica, Acacia seyal var. seyal and Acacia tortilis). Phytochemical study was piloted to detect the bioactive compounds, which have been responsible from the biological activities. The ethanol, chloroform and acetone plant extracts were seasoned against standard bacteria strains of gram +ve bacteria Staphylococcus aureus (ATCC 25923), Gram -ve bacteria Pseudomonas aeruginosa (ATCC 27853) and standard fungi Candida albicans (ATCC 90028), using cup-plate method. The antioxidant activities were conducted via DPPH radical scavenging and metal chelating assays. Prospective activity against the five species was observed in acetone extract. Ethanol extract showed highest activities against Staphylococcus aureus, and Candida albicans. Potential antioxidant activity was presented by ethanol. Cholorophorm and acetone extracts via DPPH, the radical scavenging activities were found to be 91±0.03, 88±0.01 and 85±0.04 respectively. The results of phytochemical screening showed that all extracts of studied plant contain flavonoids, saponins, terpenoids, steroids, alkaloids, phenols and tannins. This study gives rise to antioxidant, antimicrobial properties of studied plant, and showed interesting correlation with the phytochemical constituents and biological activities.

Keywords: antimicrobial, antioxidant, Acacia albidia, Acacia mellifera, Acacia nubica, Acacia seyal var. seyal, Acacia tortilis

Procedia PDF Downloads 386
944 An Introspective look into Hotel Employees Career Satisfaction

Authors: Anastasios Zopiatis, Antonis L. Theocharous

Abstract:

In the midst of a fierce war for talent, the hospitality industry is seeking new and innovative ways to enrich its image as an employer of choice and not a necessity. Historically, the industry’s professions are portrayed as ‘unattractive’ due to their repetitious nature, long and unsocial working schedules, below average remunerations, and the mental and physical demands of the job. Aligning with the industry, hospitality and tourism scholars embarked on a journey to investigate pertinent topics with the aim of enhancing our conceptual understanding of the elements that influence employees at the hospitality world of work. Topics such as job involvement, commitment, job and career satisfaction, and turnover intentions became the focal points in a multitude of relevant empirical and conceptual investigations. Nevertheless, gaps or inconsistencies in existing theories, as a result of both the volatile complexity of the relationships governing human behavior in the hospitality workplace, and the academic community’s unopposed acceptance of theoretical frameworks mainly propounded in the United States and United Kingdom years ago, necessitate our continuous vigilance. Thus, in an effort to enhance and enrich the discourse, we set out to investigate the relationship between intrinsic and extrinsic job satisfaction traits and the individual’s career satisfaction, and subsequent intention to remain in the hospitality industry. Reflecting on existing literature, a quantitative survey was developed and administered, face-to-face, to 650 individuals working as full-time employees in 4- and 5- star hotel establishments in Cyprus, whereas a multivariate statistical analysis method, namely Structural Equation Modeling (SEM), was utilized to determine whether relationships existed between constructs as a means to either accept or reject the hypothesized theory. Findings, of interest to both industry stakeholders and academic scholars, suggest that the individual’s future intention to remain within the industry is primarily associated with extrinsic job traits. Our findings revealed that positive associations exist between extrinsic job traits, and both career satisfaction and future intention. In contrast, when investigating the relationship of intrinsic traits, a positive association was revealed only with career satisfaction. Apparently, the local industry’s environmental factors of seasonality, excessive turnover, overdependence on seasonal, and part-time migrant workers, prohibit industry stakeholders in effectively investing the time and resources in the development and professional growth of their employees. Consequently intrinsic job satisfaction factors such as advancement, growth, and achievement, take backstage to the more materialistic extrinsic factors. Findings from the subsequent mediation analysis support the notion that intrinsic traits can positively influence future intentions indirectly only through career satisfaction, whereas extrinsic traits can positively impact both career satisfaction and future intention both directly and indirectly.

Keywords: career satisfaction, Cyprus, hotel employees, structural equation modeling, SEM

Procedia PDF Downloads 276
943 Synthesis of Highly Stable Pseudocapacitors From Secondary Resources

Authors: Samane Maroufi, Rasoul Khayyam Nekouei, Sajjad Mofarah

Abstract:

Fabrication of the state-of-the-art portable pseudocapacitors with the desired transparency, mechanical flexibility, capacitance, and durability is challenging. In most cases, the fabrication of such devices requires critical elements which are either under the crisis of depletion or their extraction from virgin mineral ores have sever environmental impacts. This urges the use of secondary resources instead of virgin resources in fabrication of advanced devices. In this research, ultrathin films of defect-rich Mn1−x−y(CexLay)O2−δ with controllable thicknesses in the range between 5 nm to 627 nm and transmittance (≈29–100%) have been fabricated via an electrochemical chronoamperometric deposition technique using an aqueous precursor derived during the selective purification of rare earth oxide (REOs) isolated from end-of-life nickel-metal hydride (Ni-MH) batteries. Intercalation/de-intercalation of anionic O2− through the atomic tunnels of the stratified Mn1−x−y(CexLay)O2−δ crystallites was found to be responsible for outstanding areal capacitance of 3.4 mF cm−2 of films with 86% transmittance. The intervalence charge transfer among interstitial Ce/La cations and Mn oxidation states within the Mn1−x−y(CexLay)O2−δ structure resulted in excellent capacitance retention of ≈90% after 16 000 cycles. The synthesised transparent flexible Mn1−x−y(CexLay)O2−δ full-cell pseudocapacitor device possessed the energy and power densities of 0.088 μWh cm⁻² and 843 µW cm⁻², respectively. These values show insignificant changes under vigorous twisting and bending to 45–180° confirming these value-added materials are intriguing alternatives for size-sensitive energy storage devices. This research confirms the feasibility of utilisation of secondary waste resources for the fabrication of high-quality pseudocapacitors with engineered defects with the desired flexibility, transparency, and cycling stability suitable for size-sensitive portable electronic devices.

Keywords: pseudocapacitors, energy storage devices, flexible and transparent, sustainability

Procedia PDF Downloads 82
942 Application of Customized Bioaugmentation Inocula to Alleviate Ammonia Toxicity in CSTR Anaerobic Digesters

Authors: Yixin Yan, Miao Yan, Irini Angelidaki, Ioannis Fotidis

Abstract:

Ammonia, which derives from the degradation of urea and protein-substrates, is the major toxicant of the commercial anaerobic digestion reactors causing loses of up to 1/3 of their practical biogas production, which reflects directly on the overall revenue of the plants. The current experimental work is aiming to alleviate the ammonia inhibition in anaerobic digestion (AD) process by developing an innovative bioaugmentation method of ammonia tolerant methanogenic consortia. The ammonia tolerant consortia were cultured in batch reactors and immobilized together with biochar in agar (customized inocula). Three continuous stirred-tank reactors (CSTR), fed with the organic fraction of municipal solid waste at a hydraulic retention time of 15 days and operated at thermophilic (55°C) conditions were assessed. After an ammonia shock of 4 g NH4+-N L-1, the customized inocula were bioaugmented into the CSTR reactors to alleviate ammonia toxicity effect on AD process. Recovery rate of methane production and methanogenic activity will be assessed to evaluate the bioaugmentation performance, while 16s rRNA gene sequence will be used to reveal the difference of microbial community changes through bioaugmentation. At the microbial level, the microbial community structures of the four reactors will be analysed to find the mechanism of bioaugmentation. Changes in hydrogen formation potential will be used to predict direct interspecies electron transfer (DIET) between ammonia tolerant methanogens and syntrophic bacteria. This experimental work is expected to create bioaugmentation inocula that will be easy to obtain, transport, handled and bioaugment in AD reactors to efficiently alleviate the ammonia toxicity, without alternating any of the other operational parameters including the ammonia-rich feedstocks.

Keywords: artisanal fishing waste, acidogenesis, volatile fatty acids, pH, inoculum/substrate ratio

Procedia PDF Downloads 118
941 Waters Colloidal Phase Extraction and Preconcentration: Method Comparison

Authors: Emmanuelle Maria, Pierre Crançon, Gaëtane Lespes

Abstract:

Colloids are ubiquitous in the environment and are known to play a major role in enhancing the transport of trace elements, thus being an important vector for contaminants dispersion. Colloids study and characterization are necessary to improve our understanding of the fate of pollutants in the environment. However, in stream water and groundwater, colloids are often very poorly concentrated. It is therefore necessary to pre-concentrate colloids in order to get enough material for analysis, while preserving their initial structure. Many techniques are used to extract and/or pre-concentrate the colloidal phase from bulk aqueous phase, but yet there is neither reference method nor estimation of the impact of these different techniques on the colloids structure, as well as the bias introduced by the separation method. In the present work, we have tested and compared several methods of colloidal phase extraction/pre-concentration, and their impact on colloids properties, particularly their size distribution and their elementary composition. Ultrafiltration methods (frontal, tangential and centrifugal) have been considered since they are widely used for the extraction of colloids in natural waters. To compare these methods, a ‘synthetic groundwater’ was used as a reference. The size distribution (obtained by Field-Flow Fractionation (FFF)) and the chemical composition of the colloidal phase (obtained by Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Total Organic Carbon analysis (TOC)) were chosen as comparison factors. In this way, it is possible to estimate the pre-concentration impact on the colloidal phase preservation. It appears that some of these methods preserve in a more efficient manner the colloidal phase composition while others are easier/faster to use. The choice of the extraction/pre-concentration method is therefore a compromise between efficiency (including speed and ease of use) and impact on the structural and chemical composition of the colloidal phase. In perspective, the use of these methods should enhance the consideration of colloidal phase in the transport of pollutants in environmental assessment studies and forensics.

Keywords: chemical composition, colloids, extraction, preconcentration methods, size distribution

Procedia PDF Downloads 212
940 Fabrication of Superhydrophobic Galvanized Steel by Sintering Zinc Nanopowder

Authors: Francisco Javier Montes Ruiz-Cabello, Guillermo Guerrero-Vacas, Sara Bermudez-Romero, Miguel Cabrerizo Vilchez, Miguel Angel Rodriguez-Valverde

Abstract:

Galvanized steel is one of the widespread metallic materials used in industry. It consists on a iron-based alloy (steel) coated with a layer of zinc with variable thickness. The zinc is aimed to prevent the inner steel from corrosion and staining. Its production is cheaper than the stainless steel and this is the reason why it is employed in the construction of materials with large dimensions in aeronautics, urban/ industrial edification or ski-resorts. In all these applications, turning the natural hydrophilicity of the metal surface into superhydrophobicity is particularly interesting and would open a wide variety of additional functionalities. However, producing a superhydrophobic surface on galvanized steel may be a very difficult task. Superhydrophobic surfaces are characterized by a specific surface texture which is reached either by coating the surface with a material that incorporates such texture, or by conducting several roughening methods. Since galvanized steel is already a coated material, the incorporation of a second coating may be undesired. On the other hand, the methods that are recurrently used to incorporate the surface texture leading to superhydrophobicity in metals are aggressive and may damage their surface. In this work, we used a novel strategy which goal is to produce superhydrophobic galvanized steel by a two-step non-aggressive process. The first process is aimed to create a hierarchical structure by incorporating zinc nanoparticles sintered on the surface at a temperature slightly lower than the zinc’s melting point. The second one is a hydrophobization by a thick fluoropolymer layer deposition. The wettability of the samples is characterized in terms of tilting plate and bouncing drop experiments, while the roughness is analyzed by confocal microscopy. The durability of the produced surfaces was also explored.

Keywords: galvanaized steel, superhydrophobic surfaces, sintering nanoparticles, zinc nanopowder

Procedia PDF Downloads 144
939 Assessment of Heavy Metals in Irrigation Water Collected from Various Vegetables Growing Areas of Swat Valley

Authors: Islam Zeb

Abstract:

The water of poor quality used for irrigation purposes has the potential to be the direct source of contamination and a vehicle for spreading contamination in the field. A number of wide-ranging review articles have been published that highlight irrigation water as a source of heavy metals toxicity which leads to chronic diseases in the human body. Here a study was planned to determine the microbial and heavy metals status of irrigation water collected from various locations of district Swat in various months. The analyses were carried out at the Environmental Horticulture Laboratory, Department of Horticulture, The University of Agriculture Peshawar, during the year 2018 – 19. The experiment was laid out in Randomized Complete Block Design (RCBD) with two factors and three replicates. Factor A consist of different locations and factor B represent various months. The result of heavy metals concentration in different regions, maximum Lead, Cadmium, Chromium, Nickel and Copper (4.27, 0.56, 0.81, 1.33 and 1.51 mg L-1 respectively) were noted for the irrigation water samples collected from Mingora while minimum Lead, Cadmium, Chromium, Nickel and Copper concentration (2.59, 0.30, 0.27, 0.40 and 0.54 mg L-1 respectively) were noted for the samples of matta. Whereas results of heavy metals content in irrigation water samples for various months maximum content of Lead, Cadmium, Chromium, Nickel and Copper (4.56, 0.63, 1.15, 1.31 and 1.48 mg L-1 respectively) were noted for the samples collected in Jan/Feb while lowest values for Lead, Cadmium, Chromium, Nickel and Copper (2.38, 0.24, 0.21, 0.41 and 0.52 mg L-1 respectively) were noted in the samples of July/August. A significant interaction was found for all the studied parameters. It was concluded that the concentration of heavy metal was maximum in irrigation water samples collected from the Mingora location during the month of Jan/Feb because Mingora is the most polluted area as compared to other studied regions, whereas the water content in winter goes to freeze and mostly contaminated water is used for irrigation purposes.

Keywords: irrigation water, various months, different regions, heavy metals contamination, Swat

Procedia PDF Downloads 73
938 Effect of Tool Size and Cavity Depth on Response Characteristics during Electric Discharge Machining on Superalloy Metal - An Experimental Investigation

Authors: Sudhanshu Kumar

Abstract:

Electrical discharge machining, also known as EDM, process is one of the most applicable machining process for removal of material in hard to machine materials like superalloy metals. EDM process utilizes electrical energy into sparks to erode the metals in presence of dielectric medium. In the present investigation, superalloy, Inconel 718 has been selected as workpiece and electrolytic copper as tool electrode. Attempt has been made to understand the effect of size of tool with varying cavity depth during drilling of hole through EDM process. In order to systematic investigate, tool size in terms of tool diameter and cavity depth along with other important electrical parameters namely, peak current, pulse-on time and servo voltage have been varied at three different values and the experiments has been designed using fractional factorial (Taguchi) method. Each experiment has been repeated twice under the same condition in order to understand the variability within the experiments. The effect of variations in parameters has been evaluated in terms of material removal rate, tool wear rate and surface roughness. Results revel that change in tool diameter during machining affects the response characteristics significantly. Larger tool diameter yielded 13% more material removal rate than smaller tool diameter. Analysis of the effect of variation in cavity depth is notable. There is no significant effect of cavity depth on material removal rate, tool wear rate and surface quality. This indicates that number of experiments can be performed to analyze other parameters effect even at smaller depth of cavity which can reduce the cost and time of experiments. Further, statistical analysis has been carried out to identify the interaction effect between parameters.

Keywords: EDM, Inconel 718, material removal rate, roughness, tool wear, tool size

Procedia PDF Downloads 207
937 A Comparative Study on Primary Productivity in Fish Cage Culture Unit and Fish Pond in Relation to Different Level of Water Depth

Authors: Pawan Kumar Sharma, J. Stephan Sampath Kumar, D. Manikandavelu, V. Senthil Kumar

Abstract:

The total amount of productivity in the system is the gross primary productivity. The present study was carried out to understand the relationship between productivity in the cages and water depth. The experiment was conducted in the fish cages installed in the pond at the Directorate of Sustainable Aquaculture, Thanjavur, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Tamil Nadu (10° 47' 13.1964'' N; 79° 8' 16.1700''E). Primary productivity was estimated by light and dark bottle method. The measurement of primary productivity was done at different depths viz., 20 cm, 40 cm, and 60 cm. Six Biological Oxygen Demand bottles of 300 ml capacity were collected and tagged. The productivity was obtained in mg O2/l/hr. The maximum dissolved oxygen level at 20 cm depth was observed 5.62 ± 0.22 mg/l/hr in the light bottle in pond water while the minimum dissolved oxygen level at 20 cm depth in a cage was observed 3.62 ± 0.18 mg/l/hr in dark bottle. In the same way, the maximum and minimum value of dissolved oxygen was observed at 40, and 60 cm depth and results were compared. A slight change in pH was observed in the cage and pond. The maximum gross primary productivity observed was 1.97 mg/l/hr in pond at 20 cm depth while minimum gross primary productivity observed was 0.82±0.16 mg/l/hr in a cage at 60 cm depth. The community respiration was also variable with the depth in both cage and pond. Maximum community respiration was found 1.50±0.19 mg/l/hr in pond at 20 cm depth. A strong positive linear relationship was observed between primary productivity and fish yields in ponds. The pond primary productivity can contribute substantially to the nutrition of farm-raised aquaculture species, including shrimp. The growth of phytoplankton’s is dependent on the sun light, availability of primary nutrients (N, P, and K) in the water body and transparency, so to increase the primary productivity fertilization through organic manure may be done that will clean to the pond environment also.

Keywords: cage aquaculture, water depth, net primary productivity, gross primary productivity, community respiration

Procedia PDF Downloads 199