Search results for: alkali surfactant alternate gas (ASAG)

Authors: Suraj Nair, Aravindkumar Vijayalingam, Alexander Perzylo, Alois Knoll

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In the last decade robotics research and development activities have grown rapidly, especially in the domain of service robotics. Integrating service robots into human occupied spaces such as homes, offices, hospitals, etc. has become increasingly worked upon. The primary motive is to ease daily lives of humans by taking over some of the household/office chores. However, several challenges remain in systematically integrating such systems in human shared work-spaces. In addition to sensing and indoor-navigation challenges, programmability of such systems is a major hurdle due to the fact that the potential user cannot be expected to have knowledge in robotics or similar mechatronic systems. In this paper, we propose a cognitive system for service robotics which allows non-expert users to easily model system behaviour in an underspecified manner through abstract tasks and objects associated with them. The system uses domain knowledge expressed in the form of an ontology along with logical reasoning mechanisms to infer all the missing pieces of information required for executing the tasks. Furthermore, the system is also capable of recovering from failed tasks arising due to on-line disturbances by using the knowledge base and inferring alternate methods to execute the same tasks. The system is demonstrated through a coffee fetching scenario in an office environment using a mobile robot equipped with sensors and software capabilities for autonomous navigation and human-interaction through natural language.

Keywords: cognitive robotics, reasoning, service robotics, task based systems

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Authors: Daphine Namara, Jeremy I. Schwartz, Andrew K. Tusubira, Willi McFarland, Caroline Birungi, Fred C. Semitala, Martin Muddu

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Emerging evidence suggests a possible association between hyperglycemia and dolutegravir (DTG), a preferred first-line antiretroviral agent in sub-Saharan Africa (SSA). There is a need for rigorous studies to validate this association in the face of increasing DTG use and the burden of non-communicable diseases among people living with HIV (PLHIV). We conducted a case-control study to assess the risk of hyperglycemia associated with the use of DTG among PLHIV attending Mulago ISS Clinic in Kampala. Cases had hyperglycemia, while controls had no hyperglycemia, as confirmed by fasting plasma glucose and oral glucose tolerance tests. Demographic, laboratory, and clinical data were collected using interviewer-administered questionnaires and medical record abstraction. The analysis compared cases and controls on DTG use prior to diagnosis of hyperglycemia while controlling for potential confounders using multivariable logistic regression. We included 204 cases and 231 controls. In multivariable analysis, patients with prior DTG use had seven times greater odds of subsequent diagnosis of hyperglycemia compared to those who had non-DTG-based regimens (adjusted odds ratio [aOR] 7.01, 95% CI 1.96-25.09). The odds of hyperglycemia also increased with age (56 years and above vs. 18-35, aOR 12.38, 95% CI 3.79-40.50) and hypertension (aOR 5.78, 95% CI 2.53-13.21). Our study demonstrates a strong association between prior DTG exposure and subsequent diagnosis of hyperglycemia. Given the benefits of DTG, wide-scale use, and the growing burden of diabetes mellitus (DM) in SSA, there is a need for systematic screening for hyperglycemia and consideration of alternate regimens for those at risk for DM.

Keywords: HIV, hyperglycemia, doluteravir, diabetes

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Authors: Jyosthna Khanna Goli, Shaik Naseeruddin, Hameeda Bee

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Employing lignocellulosic biomass in fermentative production of xylitol and bioethanol is gaining interest as it is renewable, cheap, and abundantly available. Xylitol is a polyol, gaining its importance in the food and pharmacological industry due to its low calorific value and anti-cariogenic nature. Bioethanol from lignocellulosic biomass is widely accepted as an alternative fuel for transportation with reduced CO₂ emissions, thus reducing the greenhouse effect. Typha latifolia, an aquatic weed, was found to be promising lignocellulosic substrate as it posses a high amount of sugars and does not compete with arable lands and interfere with food and feed competition. In the present study, xylose from hemicellulosic fraction of typha is converted to xylitol by isolate Jfh5 (Candida. tropicalis) and cellulose part to ethanol using Saccharomyces cerevisiaeVS3. Initially, alkali pretreatment of typha using sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, sodium bisulphate and sodium dithionate for overnight (18h) at room temperature (28 ± 2°C), resulted in maximum delignification of 75% with 2% (v/v) sodium bisulphate. Later, pretreated biomass was subjected to acid hydrolysis with 1%, 1.5%, 2%, and 3% H₂SO₄ at 110 °C and 121°C for 30 and 60 min, respectively. 2% H₂SO₄ at 121°C for 60 min was found to release 13.5 g /l sugars, which on detoxification and fermentation produced 8.1g/l xylitol with yield and productivity of 0.65g/g and 0.112g/l/h respectively. Further enzymatic hydrolysis of the residual substrate obtained after acid hydrolysis released 11g/l sugar, which on fermentation with VS3 produced 4.9g/l ethanol with yield and productivity of 0.22g/g and 0.136g/l/h respectively.

Keywords: delignification, xylitol, bioethanol, acid hydrolysis, enzyme hydrolysis

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Authors: Juan Patricio Ibáñez, Exequiel López

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A method for synthesizing copper nanoparticles through an electrochemical approach is proposed, employing surfactants to stabilize the size of the newly formed nanoparticles. The electrolyte was made up of a matrix of H₂SO₄ (190 g/L) having Cu²⁺ (from 3.2 to 9.5 g/L), sodium dodecyl sulfate -SDS- (from 0.5 to 1.0 g/L) and Tween 80 (from 0 to 7.5 mL/L). Tween 80 was used in a molar relation of 1 to 1 with SDS. A glass cell was used, which was in a thermostatic water bath to keep the system temperature, and the electrodes were cathodic copper as an anode and stainless steel 316-L as a cathode. This process was influenced by the control exerted through the initial copper concentration in the electrolyte and the applied current density. Copper nanoparticles of electrolytic purity, exhibiting a spherical morphology of varying sizes with low dispersion, were successfully produced, contingent upon the chemical composition of the electrolyte and current density. The minimum size achieved was 3.0 nm ± 0.9 nm, with an average standard deviation of 2.2 nm throughout the entire process. The deposited copper mass ranged from 0.394 g to 1.848 g per hour (over an area of 25 cm²), accompanied by an average Faradaic efficiency of 30.8% and an average specific energy consumption of 4.4 kWh/kg. The chemical analysis of the product employed X-ray powder diffraction (XRD), while physical characteristics such as size and morphology were assessed using atomic force microscopy (AFM). It was identified that the initial concentration of copper and the current density are the variables defining the size and dispersion of the nanoparticles, as they serve as reactants in the cathodic half-reaction. The presence of surfactants stabilizes the nanoparticle size as their molecules adsorb onto the nanoparticle surface, forming a thick barrier that prevents mass transfer with the exterior and halts further growth.

Keywords: copper nanopowder, electrochemical synthesis, current density, surfactant stabilizer

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Authors: Abdulrahman Abdulhamid Arabo, Raji Arabi Bamanga, Mujiburrahman Fadilu, Musa Abubakar, Fatima Abdullahi Shehu, Hafeez Muhammad Yakasai, Nasiru Abdullahi

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The aim of this study was to isolate and identify biosurfactant-producing and diesel alkanes degrading bacteria. For this reason, bacteria isolated from the diesel-contaminated site were screened for their potential to produce biosurfactants and degrade diesel alkanes. Primary selection of diesel degraders was carried out by using the conventional enrichment culture technique, where 12 bacterial strains were isolated based on their ability to grow on minimal media supplemented with diesel as the sole carbon source, which was followed by qualitative screening methods for potential biosurfactant production. Isolate B11 was the only candidate that showed positive signs for drop collapse, foaming, hemolytic test, oil displacement of more than 22 ± 0.05 mm, and emulsification (E24) of 14 ± 0.30%. The effect of various culture parameters (incubation time, diesel concentration, nitrogen source, pH and temperature) on the biodegradation of diesel was evaluated. The optimum incubation time was confirmed to be 120 days for isolate B11, and the optimum PH was confirmed as 8.0 for the isolate; similarly, the optimum temperature was confirmed as 35oC. In addition, diesel oil was used as the sole carbon source for the isolates. The favorable diesel concentration was 12.5 % (v/v) for the isolate. The isolate has shown degradative ability towards Tridecane (C13), dodecane, 2, 6, 10-trimethyl- (C15), Tetradecane (C14), 2,6,10-Trimethyltridecane (C16), Pentadecane (C15). It degraded between 0.27% - 9.65% of individual diesel oil alkanes. The strain has exhibited the potential of degrading diesel oil n-alkanes and was identified as Alcaligenes species strain B11 (MZ027604) using the 16S rRNA. Sequencing.

Keywords: diesel oil, biosurfactant, Alcaligenes sp, biodegradation

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Authors: P. Vinayagam, A. Madhanagopal

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This experimental investigation focuses on the study of the strength of concrete with ceramic waste as coarse aggregate. It is not a new concept of using alternate materials for aggregates. Pottery and ceramics have been an important part of human culture for thousands of years. The ceramic waste from ceramic and construction industries is a major contribution to construction demolition waste (CDW), representing a serious environmental, technical, and economical problem of today’s society. The major sources of ceramic waste are ceramic industry, building construction and building demolition. In ceramic industries, a significant part of the losses in the manufacturing of ceramic elements is not returned to the production process. In building construction, ceramic waste is produced during transportation to the building site, on the execution of several construction elements and on subsequent works. This waste is regionally deposited in dumping grounds, without any separation or reuse. In this study an attempt has been made to find the suitability of the ceramic industrial wastes as a possible replacement for conventional crushed stone coarse aggregate in high performance concrete. In this study, glazed stoneware pipe waste was used as coarse aggregates. In this investigation, physical properties of ceramic waste coarse aggregates were studied. Experiments were carried out to determine the strength of high performance concrete with silica fume and ceramic stoneware pipe waste coarse aggregate of 10%, 20%, 30%, 40% and 50% different replacement ratios in comparison with those of corresponding conventional concrete mixes.

Keywords: ceramic waste, coarse aggregate replacement, glazed stoneware pipe waste, silica fume

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Authors: Adriano Mortada

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Human history is rife with conflict, and the question of refugee status determination and their rehabilitation has been up for debate since. Refugee Status Determination is the administrative or legal process by which UNHCR or governments determine whether a person seeking international protection or asylum can be identified as a refugee under international, regional, or national law. Refugee Status Determination is considered to be a vital process in aiding refugees’ realization of their rights under international law. One of the major reasons why the refugee status determination is considered an “issue”, and is one that is much debated upon annually, is the fact that the national bureaucratic systems are rigid and unbending. This is particularly concerning in the 21st century despite human advancement in policy and diplomacy, working in tandem with the United Nations and their charters and resolutions on human rights and dignity. The paper seeks to criticize the European member states' response to the refugee crisis and their inflexible and prejudiced bureaucratic systems when it comes to refugee status determination. The paper looks at multiple case studies as primary evidence and the alternate case studies where the system helped refugees, like those in Jordan, Pakistan, Turkey, and Lebanon. The main concern of the paper is to highlight the bias in the selected European systems, which do not stem from the Human Rights Charter but rather on the basis of geographical backgrounds, cultural and religious affiliations of those seeking refugee status or asylum in their respective countries. The paper hopes to not only create awareness about this issue but also provide a research background to advocacy programs to bring a change in the systems.

Keywords: refugee status determination, human rights, bureaucracy, United Nations, European Union

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Authors: Phillip Ahn, Bryan Kim

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Copper is perhaps the most prevalent heavy metal used in the manufacturing industries, from food additives to metal-mechanic factories. Common methodologies to remove copper are expensive and produce undesired by-products. A good decontaminating candidate should be environment-friendly, inexpensive, and capable of eliminating low concentrations of the metal. This work suggests chemically modified spent tea leaves of chamomile, peppermint and green tea in their thiolated, sulfonated and carboxylated forms as candidates for the removal of copper from solutions. Batch experiments were conducted to maximize the adsorption of copper (II) ions. Effects such as acidity, salinity, adsorbent dose, metal concentration, and presence of surfactant were explored. Experimental data show that maximum adsorption is reached at neutral pH. The results indicate that Cu(II) can be removed up to 53%, 22% and 19% with the thiolated, carboxylated and sulfonated adsorbents, respectively. Maximum adsorption of copper on TPM (53%) is achieved with 150 mg and decreases with the presence of salts and surfactants. Conversely, sulfonated and carboxylated adsorbents show better adsorption in the presence of surfactants. Time-dependent experiments show that adsorption is reached in less than 25 min for TCM and 5 min for SCM. Instrumental analyses determined the presence of active functional groups, thermal resistance, and scanning electron microscopy, indicating that both adsorbents are promising materials for the selective recovery and treatment of metal ions from wastewaters. Finally, columns were prepared with these adsorbents to explore their application in scaled-up processes, with very positive results. A long-term goal involves the recycling of the exhausted adsorbent and/or their use in the preparation of biofuels due to changes in materials’ structures.

Keywords: heavy metal removal, adsorption, wastewaters, water remediation

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Authors: Vinh Duy Cao, Shima Pilehvar, Anna M. Szczotok, Anna-Lena Kjøniksen

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The total energy consumption is dramatically increasing on over the world, especially for building energy consumption where a significant proportion of energy is used for heating and cooling purposes. One of the solutions to reduce the energy consumption for the building is to improve construction techniques and enhance material technology. Recently, microcapsulated phase change materials (MPCM) with high energy storage capacity within the phase transition temperature of the materials is a potential method to conserve and save energy. A new composite materials with high energy storage capacity by mixing MPCM into concrete for passive building technology is the promising candidate to reduce the energy consumption. One of the most untilized building materials for mixing with MPCM is Portland cement concrete. However, the emission of carbon dioxide (CO2) due to producing cement which plays the important role in the global warming is the main drawback of PCC. Accordingly, an environmentally friendly building material, geopolymer, which is synthesized by the reaction between the industrial waste material (aluminosilicate) and a strong alkali activator, is a potential materials to mixing with MPCM. Especially, the effect of MPCM on the thermal and mechanical properties of geopolymer concrete (GPC) is very limited. In this study, high thermal energy storage capacity materials were fabricated by mixing MPCM into geopolymer concrete. This article would investigate the effect of MPCM concentration on thermal and mechanical properties of GPC. The target is to balance the effect of MPCM on improving the thermal performance and maintaining the compressive strength of the geopolymer concrete at an acceptable level for building application.

Keywords: microencapsulated phase change materials, geopolymer concrete, energy storage capacity, thermal performance

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Authors: Henar Martín-Sanz García, Eleni Chatzi, Eugen Brühwiler

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Located on the shore of Geneva Lake, in Switzerland, the Chillon Viaducts are two parallel structures consisted of post-tensioned concrete box girders, with a total length of 2 kilometers and 100m spans. Built in 1969, the bridges currently accommodate a traffic load of 50.000 vehicles per day, thereby holding a key role both in terms of historic value as well as socio-economic significance. Although several improvements have been carried out in the past two decades, recent inspections demonstrate an Alkali-Aggregate reaction in the concrete deck and piers reducing the concrete strength. In order to prevent further expansion of this issue, a layer of 40 mm of Ultra High Performance Fiber Reinforced cement-based Composite (UHPFRC) (incorporating rebars) was casted over the slabs, acting as a waterproof membrane and providing significant increase in resistance of the bridge structure by composite UHPFRC – RC composite action in particular of the deck slab. After completing the rehabilitation works, a Structural Monitoring campaign was installed on the deck slab in one representative span, based on accelerometers, strain gauges, thermal and humidity sensors. This campaign seeks to reveal information on the behavior of UHPFRC-concrete composite systems, such as increase in stiffness, fatigue strength, durability and long-term performance. Consequently, the structural monitoring is expected to last for at least three years. A first insight of the analyzed results from the initial months of measurements is presented herein, along with future improvements or necessary changes on the deployment.

Keywords: composite materials, rehabilitation, structural health monitoring, UHPFRC

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Authors: Kateryna Zhdanova, Evelyn Szeinbaum, Michelle Lo, Yeonjae Jo, Abel E. Navarro

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Alginate hydrogel beads (AB), spent peppermint leaf (PM), and a hybrid adsorbent of these two materials (ABPM) were studied as potential biosorbents of Cobalt (II) ions from aqueous solutions. Cobalt ion is a commonly underestimated pollutant that is responsible for several health problems. Discontinuous batch experiments were conducted at room temperature to evaluate the effect of solution acidity, mass of adsorbent on the adsorption of Co(II) ions. The interfering effect of salinity, the presence of surfactants, an organic dye, and Pb(II) ions were also studied to resemble the application of these adsorbents in real wastewater. Equilibrium results indicate that Co(II) uptake is maximized at pH values higher than 5, with adsorbent doses of 200 mg, 200 mg, and 120 mg for AB, PM, and ABPM, respectively. Co(II) adsorption followed the trend AB > ABPM > PM with Adsorption percentages of 77%, 71% and 64%, respectively. Salts had a strong negative effect on the adsorption due to the increase of the ionic strength and the competition for adsorption sites. The presence of Pb(II) ions, surfactant, and dye BY57 had a slightly negative effect on the adsorption, apparently due to their interaction with different adsorption sites that do not interfere with the removal of Co(II). A polar-electrostatic adsorption mechanism is proposed based on the experimental results. Scanning electron microscopy indicates that adsorbent has appropriate morphological and textural properties, and also that ABPM encapsulated most of the PM inside of the hydrogel beads. These experimental results revealed that AB, PM, and ABPM are promising adsorbents for the elimination of Co(II) ions from aqueous solutions under different experimental conditions. These biopolymers are proposed as eco-friendly alternatives for the removal of heavy metal ions at lower costs than the conventional techniques.

Keywords: adsorption, Co(II) ions, alginate hydrogel beads, spent peppermint leaf, pH

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Authors: Zayedali Shaikh

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Increasingly now more than ever, UV damage brings with it a litany of minor deformities that can range from mild lesions and discoloring to cataracts and blindness. Pluripotent stem cells in planaria and human skin can be used to treat wounds and skin damage, with the primary limitations being inadequate growth factors. Photobiomodulation therapy in the form of low-intensity red light therapy has been proven to provide helpful benefits in the healing of skin that displays some of the symptoms of UV damage, such as burns and lesions, along with stimulating the proliferation of stem cells in recellularizing tissue. This paper puts forth an alternate means by which to treat the effects of UV damage using the freshwater planarian model system, Dugesia dorotocephala, known for its regenerative abilities and abundance of pluripotent stem cells, which allow for the rapid growth and repair of missing or damaged structures. Our work consisted of exposing planaria to different types of light: red light, blue light, white light, darkness, red and blue light together, UV light, and finally, red and UV light together. The primary focus of this research was on the red and UV lights, with six controls acting as metrics to compare our findings. Through computer-assisted morphological analysis, the results show that there is no significant difference in the rates of regeneration of planaria treated with simultaneous exposure to red and UV light versus planaria in darkness (p > .05), a representation of their preferred natural habitat. Our research suggests the viability of red-light therapy in actively combating UV damage and expediting the growth of epidermal stem cells by acting as another growth factor.

Keywords: regenerative medicine, stem cells, planaria, photobiomodulation

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Authors: Januar Parlaungan Siregar, Davindra Brabu Mathivanan, Dandi Bachtiar, Mohd Ruzaimi Mat Rejab, Tezara Cionita

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Natural fibres play a significant role in mass industries such as automotive, construction and sports. Many researchers have found that the natural fibres are the best replacement for the synthetic fibres in terms of cost, safety, and degradability due to the shortage of landfill and ingestion of non biodegradable plastic by animals. This study mainly revolved around pineapple leaf fibre (PALF) which is available abundantly in tropical countries and with excellent mechanical properties. The composite formed in this study is highly biodegradable as both fibre and matrix are both derived from natural based products. The matrix which is polylactic acid (PLA) is made from corn starch which gives the upper hand as both material are renewable resources are easier to degrade by bacteria or enzyme. The PALF is treated with different alkaline solution to remove excessive moisture in the fibre to provide better interfacial bonding with PLA. Thereafter the PALF is washed with distilled water several times before placing in vacuum oven at 80°C for 48 hours. The dried PALF later were mixed with PLA using extrusion method using fibre in percentage of 30 by weight. The temperature for all zone were maintained at 160°C with the screw speed of 50 rpm for better bonding and afterwards the products of the mixture were pelletized using pelletizer. The pellets were placed in the specimen-sized mould for hot compression under the temperature of 170°C at 5 MPa for 5 min and subsequently were cold pressed under room temperature at 5 MPa for 5 min. The specimen were tested for tensile and flexure strength according to American Society for Testing and Materials (ASTM) D638 and D790 respectively. The effect of surface modification on PALF with different alkali solution will be investigated and compared.

Keywords: natural fibre, PALF, PLA, composite

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Authors: Meenakshi Verma, Mandeep Singh Bakshi, Kultar Singh

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Magnetic nanoparticles have received incredible importance in view of their diverse applications, which arise primarily due to their response to the external magnetic field. The magnetic behaviour of magnetic nanoparticles (NPs) helps them in numerous different ways. The most important amongst them is the ease with which they can be purified and also can be separated from the media in which they are present merely by applying an external magnetic field. This exceptional ease of separation of the magnetic NPs from an aqueous media enables them to use for extracting/removing metal pollutants from complex aqueous medium. Functionalized magnetic NPs can be subjected for the metallic impurities extraction if are favourably adsorbed on the NPs surfaces. We have successfully used the magnetic NPs as vehicles for gold and silver NPs removal from the complex fluids. The NPs loaded with gold and silver NPs pollutant fractions has been easily removed from the aqueous media by using external magnetic field. Similarly, we have used the magnetic NPs for extraction of protein from complex media and then constantly washed with pure water to eliminate the unwanted surface adsorbed components for quantitative estimation. The purified and protein loaded magnetic NPs are best analyzed with SDS Page to not only for characterization but also for separating the protein fractions. A collective review of the results indicates that we have synthesized surfactant coated iron oxide NPs and then functionalized these with selected materials. These surface active magnetic NPs work very well for the extraction of metallic NPs from the aqueous bulk and make the whole process environmentally sustainable. Also, magnetic NPs-Au/Ag/Pd hybrids have excellent protein extracting properties. They are much easier to use in order to extract the magnetic impurities as well as protein fractions under the effect of external magnetic field without any complex conventional purification methods.

Keywords: magnetic nanoparticles, protein, functionalized, extraction

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Authors: Ufaith Qadri, M Marouf Wani

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In this paper, the performance and emission characteristics of a Single Cylinder Spark Ignition engine have been investigated. The research is based on micro emulsion application as fuel in a gasoline engine. We have analyzed many micro emulsion compositions in various proportions, for predicting the performance of the Spark Ignition engine. This new technology of fuel modifications is emerging very rapidly as lot of research is going on in the field of micro emulsion fuels in Compression Ignition engines, but the micro emulsion fuel used in a Gasoline engine is very rare. The use of micro emulsion as fuel in a Spark Ignition engine is virtually unexplored. So, our main goal is to see the performance and emission characteristics of micro emulsions as fuel, in Spark Ignition engines, and finding which composition is more efficient. In this research, we have used various micro emulsion fuels whose composition varies for all the three blends, and their performance and emission characteristic were predicted in AVL Boost software. Conventional Gasoline fuel 90%, 80% and 85% were blended with co-surfactant Ethanol in different compositions, and water was used as an additive for making it crystal clear transparent micro emulsion fuel, which is thermodynamically stable. By comparing the performances of engines, the power has shown similarity for micro emulsion fuel and conventional Gasoline fuel. On the other hand, Torque and BMEP shows increase for all the micro emulsion fuels. Micro emulsion fuel shows higher thermal efficiency and lower Specific Fuel Consumption for all the compositions as compared to the Gasoline fuel. Carbon monoxide and Hydro carbon emissions were also measured. The result shows that emissions decrease for all the composition of micro emulsion fuels, and proved to be the most efficient fuel both in terms of performance and emission characteristics.

Keywords: AVL Boost, emissions, microemulsions, performance, Spark Ignition (SI) engine

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Authors: Mohadese Hashemi, Elham Akhoundi Kharanaghi, Fatemeh Haghiralsadat, Mojgan Yazdani, Omid Javani, Mahboobe Sharafodini, Davood Rajabi

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Niosomes are non-ionic surfactant vesicles in aqueous media resulting in closed bilayer structures that can be used as carriers of hydrophilic and hydrophobic compounds. The use of niosomes for encapsulation of essential oils (EOs) is an attractive new approach to overcome their physicochemical stability concerns include sensibility to oxygen, light, temperature, and volatility, and their reduced bioavailability which is due to low solubility in water. EOs are unstable and fragile volatile compounds which have strong interest in pharmaceutical due to their medicinal properties such as antiviral, anti-inflammatory, antifungal, and antioxidant activities without side effects. Trachyspermum copticum (ajwain) is an annual aromatic plant with important medicinal properties that grows widely around Mediterranean region and south-west Asian countries. The major components of the ajwain oil were reported as thymol, γ-terpinene, p-cymene, and carvacrol which provide antimicrobial and antioxidant activity. The aim of this work was to formulate ajwain essential oil-loaded niosomes to improve water solubility of natural product and evaluate its physico-chemical features and stability. Ajwain oil was obtained through steam distillation using a clevenger-type apparatus and GC/MS was applied to identify the main components of the essential oil. Niosomes were prepared by using thin film hydration method and nanoparticles were characterized for particle size, dispersity index, zeta potential, encapsulation efficiency, in vitro release, and morphology.

Keywords: trachyspermum copticum, ajwain, niosome, essential oil, encapsulation

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Authors: N. N. Orlova, A. S. Aronin, Yu. P. Kabanov, S. I. Bozhko, V. S. Gornakov

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We have investigated the change of the magnetic structure and the hysteresis properties of iron-based microwires after decreasing levels of internal mechanical stresses. The magnetic structure was investigated by the method of magneto-optical indicator film and the method of magnetic force microscopy. The hysteresis properties were studied by the vibrating sample magnetometer. The stresses were decreased by removing the glass coat and/or by low-temperature isothermal annealing. Previously, the authors carried out experimentally investigation of the magnetic structure of Fe-based microwire using these methods. According to the obtained results the domain structure of a microwire with a positive magnetostriction is composed of the inner cylindrical domains with the magnetization along the wire axis and the surface layer of the ring shape domains with the radial direction of magnetization. Surface ring domains with opposite magnetization direction (i.e., to the axis or from the axis) alternate with each other. For the first time the size of magnetic domains was determined experimentally. In this study it was found that in the iron-based microwires the value of the coercive force can be reduce more than twice by decreasing levels of internal mechanical stresses. Decrease of the internal stress value by the relaxation annealing influence on the magnetic structure. So in the as-prepared microwires observed local deviations of the magnetization of the magnetic core domains from the axis of the wire. After low-temperature annealing the local deviations of magnetization is not observed.

Keywords: amorphous microwire, magnetic structure, internal stress, hysteresis properties, ferromagnetic

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Authors: Maliheh Raji, Hossein Abolghasemi, Jaber Safdari, Ali Kargari

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Dysprosium is a rare earth element which is essential for many growing high-technology applications. Dysprosium along with neodymium plays a significant role in different applications such as metal halide lamps, permanent magnets, and nuclear reactor control rods preparation. The purification and separation of rare earth elements are challenging because of their similar chemical and physical properties. Among the various methods, membrane processes provide many advantages over the conventional separation processes such as ion exchange and solvent extraction. In this work, selective extraction and separation of dysprosium from aqueous solutions containing an equimolar mixture of dysprosium and neodymium by emulsion liquid membrane (ELM) was investigated. The organic membrane phase of the ELM was a nanofluid consisting of multiwalled carbon nanotubes (MWCNT), Span80 as surfactant, Cyanex 272 as carrier, kerosene as base fluid, and nitric acid solution as internal aqueous phase. Factors affecting separation of dysprosium such as carrier concentration, MWCNT concentration, feed phase pH and stripping phase concentration were analyzed using Taguchi method. Optimal experimental condition was obtained using analysis of variance (ANOVA) after 10 min extraction. Based on the results, using MWCNT nanofluid in ELM process leads to increase the extraction due to higher stability of membrane and mass transfer enhancement and separation factor of 6 for dysprosium over neodymium can be achieved under the optimum conditions. Additionally, demulsification process was successfully performed and the membrane phase reused effectively in the optimum condition.

Keywords: emulsion liquid membrane, MWCNT nanofluid, separation, Taguchi method

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Authors: Boris Djartov, Sanaz Mostaghim

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This paper presents a number-based dominance method. The main idea is how to fragment the many attributes of the problem into subsets suitable for the well-established concept of Pareto dominance. Although other similar methods can be found in the literature, they focus on comparing the solutions one objective at a time, while the focus of this method is to compare entire subsets of the objective vector. Given the nature of the method, it is computationally costlier than other methods and thus, it is geared more towards selecting an option from a finite set of alternatives, where each solution is defined by multiple objectives. The need for this method was motivated by dynamic alternate airport selection (DAAS). In DAAS, pilots, while en route to their destination, can find themselves in a situation where they need to select a new landing airport. In such a predicament, they need to consider multiple alternatives with many different characteristics, such as wind conditions, available landing distance, the fuel needed to reach it, etc. Hence, this method is primarily aimed at human decision-makers. Many methods within the field of multi-objective and many-objective decision-making rely on the decision maker to initially provide the algorithm with preference points and weight vectors; however, this method aims to omit this very difficult step, especially when the number of objectives is so large. The proposed method will be compared to Favour (1 − k)-Dom and L-dominance (LD) methods. The test will be conducted using well-established test problems from the literature, such as the DTLZ problems. The proposed method is expected to outperform the currently available methods in the literature and hopefully provide future decision-makers and pilots with support when dealing with many-objective optimization problems.

Keywords: multi-objective decision-making, many-objective decision-making, multi-objective optimization, many-objective optimization

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Authors: Deepa S N, Srinivasan a D, Veeramanju K T

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The power transformer is a critical equipment in the transmission and distribution network that must be managed to ensure uninterrupted power service. The liquid insulation is essential for the proper functioning of the transformer, as it serves as both coolant and insulating medium, which influences the transformer’s durability. Further, the insulating state of a power transformer has a significant impact on its reliability. Mineral oil derived from petroleum crude oil has been employed as liquid dielectrics for decades due to its superior functional characteristics, however as a resource for the same are getting depleted over the years. Research is undertaken across the globe to identify a viable substitute for mineral oil. Further, alternate insulating oils are being investigated for better environmental impact, biodegradability and economics. Several combinations of vegetable oil derived natural esters are being inspected by researchers across the globe in these domains. In this work, mineral oil is blended with soyabean oil with various proportions and dielectric properties such as dielectric breakdown voltage, relative permittivity, dissipation factor, viscosity, flash and fire point have been investigated according to international standards. A quantitative comparison is made among various samples and is observed that the blended oil sample of equal proportion of mineral oil and soyabean oil, MO50+SO50 exhibits superior dielectric properties such as breakdown voltage of 65kV, dissipation factor of 0.0044, relative permittivity of 3.1680 that are closer to the range of values recommended for power transformer applications. Also, Breakdown voltage values of all the investigated oil samples obeyed the Weibull and Normal probability distribution.

Keywords: blended oil, dielectric breakdown, liquid insulation, power transformer

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Authors: Indu Chauhan, Bhupendra S. Butola, Paritosh Mohanty

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It is very well known that properties of material changes as their size approach to nanoscale level due to the high surface area to volume ratio. However, in last few decades, a tenet ‘structure dictates function’ is quickly being adopted by researchers working with nanomaterials. The design and exploitation of nanoparticles with tailored shape and size has become one of the primary goals of materials science researchers to expose the properties of nanostructures. To date, various methods, including soft/hard template/surfactant assisted route hydrothermal reaction, seed mediated growth method, capping molecule-assisted synthesis, polyol process, etc. have been adopted to synthesize the nanostructures with controlled size and shape and monodispersity. However controlling the shape and size of nanoparticles is an ultimate challenge of modern material research. In particular, many efforts have been devoted to rational and skillful control of hierarchical and complex nanostructures. Thus in our research work, role of cellulose in manipulating the nanostructures has been discussed. Nanoparticles of α-Fe₂O₃ (diameter ca. 15 to 130 nm) were immobilized on the cellulose fiber surface by a single step in situ hydrothermal method. However, nanoflakes of α-FeOOH having thickness ca. ~25 nm and length ca. ~250 nm were obtained by the same method in absence of cellulose fibers. A possible nucleation and growth mechanism of the formation of nanostructures on cellulose fibers have been proposed. The covalent bond formation between the cellulose fibers and nanostructures has been discussed with supporting evidence from the spectroscopic and other analytical studies such as Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The role of cellulose in manipulating the nanostructures has been discussed.

Keywords: cellulose fibers, α-Fe₂O₃, α-FeOOH, hydrothermal, nanoflakes, nanoparticles

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Authors: Ankit Patil, Tushar D. Deshpande, Yogesh M. Nimdeo

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Pickering emulsions (PE) were developed in response to increased demand for organic, eco-friendly, and biocompatible products. These emulsions are usually stabilized by solid particles. In this research, we created chitosan-based sunflower oil-in-water (O/W) PE without the need for a surfactant. In our work, we employed chitosan, a biopolymer derived from chitin, as a stabilizer. This decision was influenced by chitosan's biocompatibility and biodegradability, as well as its anti-inflammatory and antibacterial capabilities. It also has other functional properties, such as antioxidant activity, a probiotic delivery mechanism, and the ability to encapsulate bioactive compounds. The purpose of this study was to govern key parameters that can be changed to obtain stable PE, such as the concentration of chitosan (0.3-0.5 wt.%), the concentration of oil (0.8-1 vol%), the pH of the emulsion (3-7) manipulated by the addition of 1M HCl/ 4M NaOH, and the amount of electrolyte (NaCl-0-300mM) added to increase or decrease ionic strength. A careful combination of these properties resulted in the production of the most stable and optimal PE. Particle size study found that emulsions with pH 6, 0.4% chitosan, and 300 mM salts were exceptionally stable, with droplet size 886 nm, PI of 0.1702, and zeta potential of 32.753.83 mV. It is fair to infer that when ionic strength rises, particle size, zeta potential, and PI value decrease. A lower PI value suggests that emulsion nanoparticles are more homogeneous. The addition of sodium chloride increases the ionic strength of the emulsion, facilitating the formation of more compact and ordered particle layers. These findings provide light on the creation of stimulus-responsive chitosan-based PE capable of encapsulating bioactive materials, functioning as antioxidants, and serving as food-grade emulsifiers.

Keywords: pickering emulsion, biocompatibility, eco-friendly, chitosan

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Authors: Mahmoud A Rabah, Sabah M. Abelbasir

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Lead-calcium alloy containing up to 0.10% calcium was recovered from spent rechargeable sealed acid lead batteries. Two techniques were investigated to explore the effect of flux salts on the extent and quality of the recovered alloy, pyro-metallurgical and electrochemical methods. About 10 kg of the spent batteries were collected for testing. The sample was washed with hot water and dried. The plastic cases of the batteries were mechanically cut, and the contents were dismantled manually, the plastic containers were shredded for recycling. The electrode plates were freed from the loose powder and placed in SiC crucible and covered with alkali chloride salts. The loaded crucible was heated in an electronically controlled chamber furnace type Nabertherm C3 at temperatures up to 800 °C. The obtained metals were analyzed. The effect of temperature, rate of heating, atmospheric conditions, composition of the flux salts on the extent and quality of the recovered products were studied. Results revealed that the spent rechargeable batteries contain 6 blocks of 6 plates of Pb-Ca alloy each. Direct heating of these plates in a silicon carbide crucible under ambient conditions produces lead metal poor in calcium content ( < 0.07%) due to partial oxidation of the alloying calcium element. Rate of temperature increase has a considerable effect on the yield of the lead alloy extraction. Flux salts composition benefits the recovery process. Sodium salts are more powerful as compared to potassium salts. Lead calcium alloy meeting the standard specification was successfully recovered from the spent rechargeable acid lead batteries with a very competitive cost to the same alloy prepared from primary resources.

Keywords: rechargeable lead batteries, lead-calcium alloy, waste recovery, flux salts, thermal recovery

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Authors: Pramod Jagtap, Kisan Jadhav, Neha Dand

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Risperidone (RISP) is an antipsychotic agent and has low water solubility and nontargeted delivery results in numerous side effects. Hence, an attempt was made to develop SLNs hydrogel for intranasal delivery of RISP to achieve maximum bioavailability and reduction of side effects. RISP loaded SLNs composed of 1.65% (w/v) lipid mass were produced by high shear homogenization (HSH) coupled ultrasound (US) method using glyceryl monostearate (GMS) or Imwitor 900K (solid lipid). The particles were loaded with 0.2% (w/v) of the RISP & surface-tailored with a 2.02% (w/v) non-ionic surfactant Tween® 80. Optimization was done using 32 factorial design using Design Expert® software. The prepared SLNs dispersion incorporated into Polycarbophil AA1 hydrogel (0.5% w/v). The final gel formulation was evaluated for entrapment efficiency, particle size, rheological properties, X ray diffraction, in vitro diffusion, ex vivo permeation using sheep nasal mucosa and histopathological studies for nasocilliary toxicity. The entrapment efficiency of optimized SLNs was found to be 76 ± 2 %, polydispersity index <0.3., particle size 278 ± 5 nm. This optimized batch was incorporated into hydrogel. The pH was found to be 6.4 ± 0.14. The rheological behaviour of hydrogel formulation revealed no thixotropic behaviour. In histopathology study, there was no nasocilliary toxicity observed in nasal mucosa after ex vivo permeation. X-ray diffraction data shows drug was in amorphous form. Ex vivo permeation study shows controlled release profile of drug.

Keywords: ex vivo, particle size, risperidone, solid lipid nanoparticles

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Authors: Mozhgan Bahadory, Gholam-Hossein Rostami

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Over the next quarter of a century, the US government and the private sector will spend billions of dollars annually to clean the contaminated sites from pollution such as petroleum products, heavy metals, and solvents organic compounds. During the past three decades, almost 750,000 sites that require remediation have been reported to the United States federal and state agencies. Out of these contamination sites, approximately 300,000 are still in need of remediation. In these sites, the most widespread forms of contamination are petroleum products and heavy metals. At least half of US Department of Defense, US Department of Energy, Superfund sites, and Resource Conservation and Recovery Act (RCRA) sites have been reported to contain heavy metals. Heavy metals most often found in the contaminated water are lead, mercury, chromium, cadmium, arsenic, and zinc. This investigation emphasizes the elimination of arsenic and cadmium from aqueous solution. During the past several years, we developed a novel material called Alkali-Activated fly ash Material Permeable Reactive Barrier (AAM-PRB), which includes fly ash, fine aggregates, coarse aggregates, activating chemicals, and water. AAM can be produced with high permeability, 10-1 cm/s, then crushed into pelletized form. Laboratory experiments showed that water containing 10 ppm, 100 ppm, and 1000 ppm of arsenic and cadmium ion passing through AAM-PRB reduced to less than 0.1 ppm. However, water containing 10,000 ppm arsenic ion passing through AAM- PRB shows that the breakthrough was achieved. The removal of the mixture of arsenic and cadmium from aqueous solutions was also tested by using AAM-PRB. The results indicate that the efficiency of AAM-PRB for simultaneous removal of arsenic and cadmium from 10 ppm, 100 ppm, and 1,000 ppm were marginally below that of arsenic alone. Still, it was significantly lower for cadmium from the aqueous solution. The basic science behind removing heavy metal and microstructural investigation AAM-PRB will be the focus of our future work.

Keywords: arsenic, cadmium, contaminated water, fly ash, permeability, reactive barrier

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Authors: Manoj Sarda, Abhishek Agarwal, Juhi Kaushik, Vatsal Sanjay, Arup Kumar Das

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Railways in India remain primary mode of transport having one of the largest networks in the world and catering to billions of transits yearly. Catastrophic economic damage and loss to life is encountered over the past few decades due to fire to locomotives. Study of fire dynamics and fire propagation plays an important role in evacuation planning and reducing losses. Simulation based study of propagation of fire and soot inside an air conditioned coach of Indian locomotive is done in this paper. Finite difference based solver, Fire Dynamic Simulator (FDS) version 6 has been used for analysis. A single air conditioned 3 tier coupe closed to ambient surroundings by glass windows having occupancy for 8 people is the basic unit of the domain. A system of three such coupes combined is taken to be fundamental unit for the entire study to resemble effect to an entire coach. Analysis of flame and soot contours and concentrations is done corresponding to variations in heat release rate per unit volume (HRRPUA) of fire source, variations in conditioned air velocity being circulated inside coupes by vents and an alternate fire initiation and propagation mechanism via ducts. Quantitative results of fractional area in top and front view of the three coupes under fire and smoke are obtained using MATLAB (IMT). Present simulations and its findings will be useful for organizations like Commission of Railway Safety and others in designing and implementing safety and evacuation measures.

Keywords: air conditioned coaches, fire propagation, flame contour, soot flow, train fire

Procedia PDF Downloads 257

Authors: Mrunalini Sonne

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Aquaculture uses a variety of broad spectrum antibiotics to manage and prevent a variety of diseases without understanding their mechanisms of action. This has led to water pollution in the modern world. The necessity for alternate control measures against bacterial illnesses in the aquaculture sector is highlighted by issues brought on by antibiotic-resistant bacteria and the dearth of effective control strategies. Bacteriophages (phages) have shown promise as therapeutic agents for the efficient management of bacterial infections in aquaculture. In the current study, a variety of investigations were conducted to determine if utilizing lytic phages to reduce Aeromonas spp. infection in fish aquaculture was appropriate. Motile Aeromonas septicaemia is a fish disease that has caused financial harm to the aquaculture sector. Currently, the production of aquaculture depends significantly on antibiotics, which adds to the worldwide problem of the rise of bacteria that are resistant to medicines and resistance genes. To decrease the usage of antibiotics in aquaculture systems, it is crucial to create efficient antibiotic substitutes. Bacteriophages are capable of acting as a natural antagonist, mostly because of their great specificity, capacity for self-replication, and ability to quickly eradicate dangerous bacteria. There is a need for research that goes beyond just isolating and characterising lytic bacteriophages to examine their morphology, stability, and efficacy in various environmental conditions. Bacteriophage (or phage) therapy is a promising technique to control dangerous microbes in farmed fish. More phage therapy research in aquaculture is required in order to effectively employ phage treatment to lessen infection in fish brought on by Aeromonas.

Keywords: aquaculture, bacteriophages, fish, freshwater

Procedia PDF Downloads 66

Authors: Berna Istegun, Erkan Celebi

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The main objective of this experimental study is to assess the shear strength and the crack behavior of the triplets built of perforated brickwork masonry elements. In order to observe the influence of shear resistance and energy dissipating before and after retrofitting applications by using the reinforcing system, static-cyclic shear tests were employed in the structural mechanics laboratory of Sakarya University. The reinforcing system is composed of hybrid multiaxial seismic fabric consisting of alkali resistant glass and polypropylene fibers. The plaster as bonding material used in the specimen’s retrofitting consists of expanded glass granular. In order to acquire exact measuring data about the failure behavior of the two mortar joints under shear stressing, vertical load-controlled cylinder having force capacity of 50 kN and loading rate of 1.5 mm/min. with an internal inductive displacement transducers is carried out perpendicular to the triplet specimens. In this study, a total of six triplet specimens with textile reinforcement were prepared for these shear bond tests. The three of them were produced as single-sided reinforced triplets with seismic fabric, while the others were strengthened on both sides. In addition, three triplet specimens without retrofitting and plaster were also tested as reference samples. The obtained test results were given in the manner of force-displacement relationships, ductility coefficients and shear strength parameters comparatively. It is concluded that two-side seismic textile applications on masonry elements with relevant plaster have considerably increased the sheer force resistance and the ductility capacity.

Keywords: expanded glass granular, perforated brickwork, retrofitting, seismic fabric, triplet shear tests

Procedia PDF Downloads 181

Authors: Binod Shrestha, Sandrine Hoppe, Thierry Ghislain, Phillipe Marchal, Nicolas Brosse, Anthony Dufour

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The thermochemical conversion of lignin has received an increasing interest in the frame of different biorefinery concepts for the production of chemicals or energy. It is needed to better understand the physical and chemical conversion of lignin for feeder and reactor designs. In-situ rheology reveals the viscoelastic behaviour of lignin upon thermal conversion. The softening, re-solidification (char formation), swelling and shrinking behaviours are quantified during pyrolysis in real-time [1]. The in-situ rheology of an alkali lignin (Protobind 1000) was conducted in high torque controlled strain rheometer from 35°C to 400°C with a heating rate of 5°C.min-1. The swelling, through glass phase transition overlapped with depolymerization, and solidification (crosslinking and “char” formation) are two main phenomena observed during lignin pyrolysis. The onset of temperatures for softening and solidification for this lignin has been found to be 141°C and 248°C respectively. An ex-situ characterization of lignin/char residues obtained at different temperatures after quenching in the rheometer gives a clear understanding of the pathway of lignin degradation. The lignin residues were sampled from the mid-point temperatures of the softening range and solidification range to study the chemical transformations undergoing. Elemental analysis, FTIR and solid state NMR were conducted after quenching the solid residues (lignin/char). The quenched solid was also extracted by suitable solvent and followed by acetylation and GPC-UV analysis. The combination of 13C NMR and GPC-UV reveals the depolymerization followed by crosslinking of lignin/char. NMR and FTIR provide the evolution of functional moieties upon temperature. Physical and chemical mechanisms occurring during lignin pyrolysis are accounted in this study. Thanks to all these complementary methods.

Keywords: pyrolysis, bio-chemicals, valorization, mechanism, softening, solidification, cross linking, rheology, spectroscopic methods

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Authors: Alafara A. Baba, Kuranga I. Ayinla, Folahan A. Adekola, Rafiu B. Bale

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Due to increasing demands and diverse applications of copper oxide as pigment in ceramics, cuprammonium hydroxide solution for rayon, p-type semi-conductor, dry cell batteries production and as safety disposal of hazardous materials, a study on the hydrometallurgical operations involving leaching, solvent extraction and precipitation for the recovery of copper for producing high grade copper oxide from a Nigerian chalcopyrite ore in chloride media has been examined. At a particular set of experimental parameter with respect to acid concentration, reaction temperature and particle size, the leaching investigation showed that the ore dissolution increases with increasing acid concentration, temperature and decreasing particle diameter at a moderate stirring. The kinetics data has been analyzed and was found to follow diffusion control mechanism. At optimal conditions, the extent of ore dissolution reached 94.3%. The recovery of the total copper from the hydrochloric acid-leached chalcopyrite ore was undertaken by solvent extraction and precipitation techniques, prior to the beneficiation of the purified solution as copper oxide. The purification of the leach liquor was firstly done by precipitation of total iron and manganese using Ca(OH)2 and H2O2 as oxidizer at pH 3.5 and 4.25, respectively. An extraction efficiency of 97.3% total copper was obtained by 0.2 mol/L Dithizone in kerosene at 25±2ºC within 40 minutes, from which ≈98% Cu from loaded organic phase was successfully stripped by 0.1 mol/L HCl solution. The beneficiation of the recovered pure copper solution was carried out by crystallization through alkali addition followed by calcination at 600ºC to obtain high grade copper oxide (Tenorite, CuO: 05-0661). Finally, a simple hydrometallurgical scheme for the operational extraction procedure amenable for industrial utilization and economic sustainability was provided.

Keywords: chalcopyrite ore, Nigeria, copper, copper oxide, solvent extraction

Procedia PDF Downloads 367