Search results for: organic photovoltaic materials
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 9137

Search results for: organic photovoltaic materials

4967 Study on the Evaluation and Utilization of Space Renewal Potential under Bridge in Chongqing

Authors: Qin Xvelian

Abstract:

organic renewal" based on the development of existing resources in high-density urban areas has become the mainstream of urban development in the new era. As an important stock resource of public space in high-density urban areas, promoting its value remodeling is an effective way to alleviate the shortage of public space resources. However, due to the lack of evaluation links in the process of underpass space renewal, a large number of underpass space resources have been left idle, facing the problems of low space conversion efficiency, lack of accuracy in development decision-making, and low adaptability of functional positioning to citizens' needs. Therefore, it is of great practical significance to construct the evaluation system of under-bridge space renewal potential and explore the renewal mode. In this paper, some of the under-bridge spaces in the main urban area of Chongqing are selected as the research object. Through the questionnaire interviews with the users of the built excellent space under the bridge, three types of six levels and twenty-two potential evaluation indexes of "objective demand factor, construction feasibility factor and construction suitability factor" are selected, including six levels of land resources, infrastructure, accessibility, safety, space quality and ecological environment. The analytical hierarchy process and expert scoring method are used to determine the index weight, construct the potential evaluation system of the space under the bridge in high-density urban areas of Chongqing, and explore the direction of renewal and utilization of its suitability. To provide feasible theoretical basis and scientific decision support for the use of under bridge space in the future.

Keywords: high density urban area, potential evaluation, space under bridge, updated using

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4966 The Two Layers of Food Safety and GMOs in the Hungarian Agricultural Law

Authors: Gergely Horváth

Abstract:

The study presents the complexity of food safety dividing it into two layers. Beyond the basic layer of requirements, there is a more demanding higher level linked with quality and purity aspects. It would be important to give special prominence to both layers, given that massive illnesses are caused by foods even though officially licensed. Then the study discusses an exciting safety challenge stemming from the risks of genetically modified organisms (GMOs). Furthermore, it features legal case examples that illustrate how certain liability questions are solved or not yet decided in connection with the production of genetically modified crops. In addition, a special kind of land grabbing, more precisely land grabbing from non-GMO farming systems can also be noticed as well as a new phenomenon eroding food sovereignty. Coexistence, the state where organic, conventional, and GM farming systems are standing alongside each other is an unsuitable experiment that cannot be successful, because of biophysical reasons (such as cross-pollination). Agricultural and environmental lawyers both try to find the optimal solution. Agri-environmental measures are introduced as a special subfield of law maintaining also food safety. The important steps of agri-environmental legislation are aiming at the protection of natural values, the environmental media and strengthening food safety as well, practically the quality of agricultural products intended for human consumption. The major findings of the study focus on searching for the appropriate approach capable of solving the security and safety problems of food production. The most interesting concepts of the Hungarian national and EU food law legislation are analyzed in more detail with descriptive, analytic and comparative methods.

Keywords: food law, food safety, food security, GMO, Genetically Modified Organisms, agri-environmental measures

Procedia PDF Downloads 426
4965 Geoeducation Strategies for Teaching Natural Hazards in Schools

Authors: Carlos Alberto Ríos Reyes, Andrés Felipe Mejía Durán, Oscar Mauricio Castellanos Alarcón

Abstract:

There is no doubt of great importance to make it known that planet Earth is an entity in constant change and transformation; processes such as construction and destruction are part of the evolution of the territory. Geoeducation workshops represent a significant contribution to the search for educational projects focused on teaching relevant geoscience topics to make natural threats known in schools through recreational and didactic activities. This initiative represents an educational alternative that must be developed with the participation of primary and secondary schools, universities, and local communities. The methodology is based on several phases, which include: diagnosis to know the best teaching method for basic concepts and establish a starting point for the topics to be taught, as well as to identify areas and concepts that need to be reinforced and/or deepened; design of activities that involve all students regardless of their ability or level; use of accessible materials and experimentation to support clear and concise explanations for all students; adaptation of the teaching-learning process to individual needs; sensitization about natural threats; and evaluation and feedback. It is expected to offer a series of activities and materials as a significant contribution to the search for educational projects focused on teaching relevant geoscientific topics such as natural threats associated with earthquakes, volcanic eruptions, floods, landslides, etc. The major findings of this study are the pedagogical strategies that primary and secondary school teachers can appropriate to face the challenge of transferring geological knowledge and to advise decision-makers and citizens on the importance of geosciences for daily life. We conclude that the knowledge of the natural threats to our planet is very important to contribute to mitigating their risk.

Keywords: workshops, geoeducation, curriculum, geosciences, natural threats

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4964 Wood as a Climate Buffer in a Supermarket

Authors: Kristine Nore, Alexander Severnisen, Petter Arnestad, Dimitris Kraniotis, Roy Rossebø

Abstract:

Natural materials like wood, absorb and release moisture. Thus wood can buffer indoor climate. When used wisely, this buffer potential can be used to counteract the outer climate influence on the building. The mass of moisture used in the buffer is defined as the potential hygrothermal mass, which can be an energy storage in a building. This works like a natural heat pump, where the moisture is active in damping the diurnal changes. In Norway, the ability of wood as a material used for climate buffering is tested in several buildings with the extensive use of wood, including supermarkets. This paper defines the potential of hygrothermal mass in a supermarket building. This includes the chosen ventilation strategy, and how the climate impact of the building is reduced. The building is located above the arctic circle, 50m from the coastline, in Valnesfjord. It was built in 2015, has a shopping area, including toilet and entrance, of 975 m². The climate of the area is polar according to the Köppen classification, but the supermarket still needs cooling on hot summer days. In order to contribute to the total energy balance, wood needs dynamic influence to activate its hygrothermal mass. Drying and moistening of the wood are energy intensive, and this energy potential can be exploited. Examples are to use solar heat for drying instead of heating the indoor air, and raw air with high enthalpy that allow dry wooden surfaces to absorb moisture and release latent heat. Weather forecasts are used to define the need for future cooling or heating. Thus, the potential energy buffering of the wood can be optimized with intelligent ventilation control. The ventilation control in Valnesfjord includes the weather forecast and historical data. That is a five-day forecast and a two-day history. This is to prevent adjustments to smaller weather changes. The ventilation control has three zones. During summer, the moisture is retained to dampen for solar radiation through drying. In the winter time, moist air let into the shopping area to contribute to the heating. When letting the temperature down during the night, the moisture absorbed in the wood slow down the cooling. The ventilation system is shut down during closing hours of the supermarket in this period. During the autumn and spring, a regime of either storing the moisture or drying out to according to the weather prognoses is defined. To ensure indoor climate quality, measurements of CO₂ and VOC overrule the low energy control if needed. Verified simulations of the Valnesfjord building will build a basic model for investigating wood as a climate regulating material also in other climates. Future knowledge on hygrothermal mass potential in materials is promising. When including the time-dependent buffer capacity of materials, building operators can achieve optimal efficiency of their ventilation systems. The use of wood as a climate regulating material, through its potential hygrothermal mass and connected to weather prognoses, may provide up to 25% energy savings related to heating, cooling, and ventilation of a building.

Keywords: climate buffer, energy, hygrothermal mass, ventilation, wood, weather forecast

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4963 Preparation of Novel Silicone/Graphene-based Nanostructured Surfaces as Fouling Release Coatings

Authors: Mohamed S. Selim, Nesreen A. Fatthallah, Shimaa A. Higazy, Zhifeng Hao, Ping Jing Mo

Abstract:

As marine fouling-release (FR) surfaces, two new superhydrophobic nanocomposite series of polydimethylsiloxane (PDMS) loaded with reduced graphene oxide (RGO) and graphene oxide/boehmite nanorods (GO-γ-AlOOH) nanofillers were created. The self-cleaning and antifouling capabilities were modified by controlling the nanofillers' shapes and distribution in the silicone matrix. With an average diameter of 10-20 nm and a length of 200 nm, γ-AlOOH nanorods showed a single crystallinity. RGO was made using a hydrothermal process, whereas GO-γ-AlOOH nanocomposites were made using a chemical deposition method for use as fouling-release coating materials. These nanofillers were disseminated in the silicone matrix using the solution casting method to explore the synergetic effects of graphene-based materials on the surface, mechanical, and FR characteristics. Water contact angle (WCA), scanning electron, and atomic force microscopes were used to investigate the surface's hydrophobicity and antifouling capabilities (SEM and AFM). The roughness, superhydrophobicity, and surface mechanical characteristics of coatings all increased the homogeneity of the nanocomposite dispersion. To examine the antifouling effects of the coating systems, laboratory tests were conducted for 30 days using specified bacteria.PDMS/GO-γ-AlOOH nanorod composite demonstrated superior antibacterial efficacy against several bacterial strains than PDMS/RGO nanocomposite. The high surface area and stabilizing effects of the GO-γ-AlOOH hybrid nanofillers are to blame for this. The biodegradability percentage of the PDMS/GO-γ-AlOOH nanorod composite (3 wt.%) was the lowest (1.6%), while the microbial endurability percentages for gram-positive, gram-negative, and fungi were 86.42%, 97.94%, and 85.97%, respectively. The homogeneity of the GO-γ-AlOOH (3 wt.%) dispersion, which had a WCA of 151° and a rough surface, was the most profound superhydrophobic antifouling nanostructured coating.

Keywords: superhydrophobic nanocomposite, fouling release, nanofillers, surface coating

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4962 Effects of Ascophyllum nodosum in Tomato in the Tropical Caribbean Climate: Effects and Molecular Insights into Mechanisms

Authors: Omar Ali, Adesh Ramsubhag, Jayaraj Jayaraman

Abstract:

Seaweed extracts have been reported as plant biostimulants which could be a safer, organic alternative to harsh pesticides. The incentive to use seaweed-based biostimulants is becoming paramount in sustainable agriculture. The current study, therefore, screened a commercial extract of A. nodosum in tomatoes, cultivated in Trinidad to showcase the multiple beneficial effects. Foliar treatment with an A. nodosum commercial extract led to significant increases in fruit yield and a significant reduction of incidence of bacterial spots and early blight diseases under both greenhouse and field conditions. Investigations were carried out to reveal the possible mechanisms of action of this biostimulant through defense enzyme assays and transcriptome profiling via RNA sequencing of tomato. Studies into disease control mechanisms by A. nodosum showed that the extract stimulated the activity of enzymes such as peroxidase, phenylalanine ammonia-lyase, chitinase, polyphenol oxidase, and β-1,3-glucanase. Additionally, the transcriptome survey revealed the upregulation and enrichment of genes responsible for the biosynthesis of growth hormones, defense enzymes, PR proteins and defense-related secondary metabolites, as well as genes involved in the nutrient mobilization, photosynthesis and primary and secondary metabolic pathways. The results of the transcriptome study also demonstrated the cross-talks between growth and defense responses, confirming the bioelicitor and biostimulant value of seaweed extracts in plants. These effects could potentially implicate the benefits of seaweed extract and validate its usage in sustainable crop production.

Keywords: A. nodosum, biostimulants, elicitor, enzymes, growth responses, seaweeds, tomato, transcriptome analysis

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4961 Methodologies for Stability Assessment of Existing and Newly Designed Reinforced Concrete Bridges

Authors: Marija Vitanovа, Igor Gjorgjiev, Viktor Hristovski, Vlado Micov

Abstract:

Evaluation of stability is very important in the process of definition of optimal structural measures for maintenance of bridge structures and their strengthening. To define optimal measures for their repair and strengthening, it is necessary to evaluate their static and seismic stability. Presented in this paper are methodologies for evaluation of the seismic stability of existing reinforced concrete bridges designed without consideration of seismic effects and checking of structural justification of newly designed bridge structures. All bridges are located in the territory of the Republic of North Macedonia. A total of 26 existing bridges of different structural systems have been analyzed. Visual inspection has been carried out for all bridges, along with the definition of three main damage categories according to which structures have been categorized in respect to the need for their repair and strengthening. Investigations involving testing the quality of the built-in materials have been carried out, and dynamic tests pointing to the dynamic characteristics of the structures have been conducted by use of non-destructive methods of ambient vibration measurements. The conclusions drawn from the performed measurements and tests have been used for the development of accurate mathematical models that have been analyzed for static and dynamic loads. Based on the geometrical characteristics of the cross-sections and the physical characteristics of the built-in materials, interaction diagrams have been constructed. These diagrams along with the obtained section quantities under seismic effects, have been used to obtain the bearing capacity of the cross-sections. The results obtained from the conducted analyses point to the need for the repair of certain structural parts of the bridge structures. They indicate that the stability of the superstructure elements is not critical during a seismic effect, unlike the elements of the sub-structure, whose strengthening is necessary.

Keywords: existing bridges, newly designed bridges, reinforced concrete bridges, stability assessment

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4960 Products in Early Development Phases: Ecological Classification and Evaluation Using an Interval Arithmetic Based Calculation Approach

Authors: Helen L. Hein, Joachim Schwarte

Abstract:

As a pillar of sustainable development, ecology has become an important milestone in research community, especially due to global challenges like climate change. The ecological performance of products can be scientifically conducted with life cycle assessments. In the construction sector, significant amounts of CO2 emissions are assigned to the energy used for building heating purposes. Therefore, sustainable construction materials for insulating purposes are substantial, whereby aerogels have been explored intensively in the last years due to their low thermal conductivity. Therefore, the WALL-ACE project aims to develop an aerogel-based thermal insulating plaster that would achieve minor thermal conductivities. But as in the early stage of development phases, a lot of information is still missing or not yet accessible, the ecological performance of innovative products bases increasingly on uncertain data that can lead to significant deviations in the results. To be able to predict realistically how meaningful the results are and how viable the developed products may be with regard to their corresponding respective market, these deviations however have to be considered. Therefore, a classification method is presented in this study, which may allow comparing the ecological performance of modern products with already established and competitive materials. In order to achieve this, an alternative calculation method was used that allows computing with lower and upper bounds to consider all possible values without precise data. The life cycle analysis of the considered products was conducted with an interval arithmetic based calculation method. The results lead to the conclusion that the interval solutions describing the possible environmental impacts are so wide that the result usability is limited. Nevertheless, a further optimization in reducing environmental impacts of aerogels seems to be needed to become more competitive in the future.

Keywords: aerogel-based, insulating material, early development phase, interval arithmetic

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4959 Federal Center for Technological Education of Minas Gerais (CEFET-MG)

Authors: María González Alriols, Itziar Egües, María A. Andrés, Mirari Antxustegi

Abstract:

Several collaborative learning proposals were prepared to be applied in the laboratory sessions of chemistry in the first course of engineering studies. The aim was to engage the students from the beginning and to avoid absenteeism as well as to reach a more homogeneous level in the class. The students, divided into small groups of four or five mates, were asked to do an exercise before having the practical session in the lab. Precisely, each one of the groups was asked to study the theoretical fundamentals and the practical aspects of one lab session and to prepare a didactical video with this content, including the materials, equipment and reactants required, and the detailed experimental procedure. Furthermore, they should include the performance of the experiment step by step, indicating the faced difficulties and the obtained results and conclusions. After watching the video of this precise activity, the other groups of students would go to the lab to put into practice the session following the commands explained in the video. The evaluation of the video activity that is worth the 50% of the total mark of the laboratory sessions, is done depending on the success that the other groups of students had while doing the practical session that was explained in the video. This means that the successful transmission of knowledge to the rest of the mates in the class through the video was compulsory to pass the practical sessions and the subject. The other 50% of the mark depended on the understanding of the other students’ explanations and the success in the corresponding practical sessions. The experience was found to be very positive, as the engagement level was considerably higher, the absenteeism lower and the attitude in the laboratory much more responsible. The materials, reactants and equipment were used carefully, and no incidents were registered. Furthermore, the fact of having peer experts was useful to encourage critical thinking in a more relaxed way, with the teacher figure in a secondary position. Finally, the academic achievements were satisfactory as well, with a high percentage of students over the level required for passing the subject.

Keywords: collaborative learning, engineering instruction, chemistry, laboratory sessions

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4958 Assessment of a Coupled Geothermal-Solar Thermal Based Hydrogen Production System

Authors: Maryam Hamlehdar, Guillermo A. Narsilio

Abstract:

To enhance the feasibility of utilising geothermal hot sedimentary aquifers (HSAs) for clean hydrogen production, one approach is the implementation of solar-integrated geothermal energy systems. This detailed modelling study conducts a thermo-economic assessment of an advanced Organic Rankine Cycle (ORC)-based hydrogen production system that uses low-temperature geothermal reservoirs, with a specific focus on hot sedimentary aquifers (HSAs) over a 30-year period. In the proposed hybrid system, solar-thermal energy is used to raise the water temperature extracted from the geothermal production well. This temperature increase leads to a higher steam output, powering the turbine and subsequently enhancing the electricity output for running the electrolyser. Thermodynamic modeling of a parabolic trough solar (PTS) collector is developed and integrated with modeling for a geothermal-based configuration. This configuration includes a closed regenerator cycle (CRC), proton exchange membrane (PEM) electrolyser, and thermoelectric generator (TEG). Following this, the study investigates the impact of solar energy use on the temperature enhancement of the geothermal reservoir. It assesses the resulting consequences on the lifecycle performance of the hydrogen production system in comparison with a standalone geothermal system. The results indicate that, with the appropriate solar collector area, a combined solar-geothermal hydrogen production system outperforms a standalone geothermal system in both cost and rate of production. These findings underscore a solar-assisted geothermal hybrid system holds the potential to generate lower-cost hydrogen with enhanced efficiency, thereby boosting the appeal of numerous low to medium-temperature geothermal sources for hydrogen production.

Keywords: clean hydrogen production, integrated solar-geothermal, low-temperature geothermal energy, numerical modelling

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4957 Evaluating Aquaculture Farmers Responses to Climate Change and Sustainable Practices in Kenya

Authors: Olalekan Adekola, Margaret Gatonye, Paul Orina

Abstract:

The growing demand for farmed fish by underdeveloped and developing countries as a means of contributing positively towards eradication of hunger, food insecurity, and malnutrition for their fast growing populations has implications to the environment. Likewise, climate change poses both an immediate and future threat to local fish production with capture fisheries already experiencing a global decline. This not only raises fundamental questions concerning how aquaculture practices affect the environment, but also how ready are aquaculture farmers to adapt to climate related hazards. This paper assesses existing aquaculture practices and approaches to adapting to climate hazards in Kenya, where aquaculture has grown rapidly since the year 2009. The growth has seen rise in aquaculture set ups mainly along rivers and streams, importation of seed and feed and intensification with possible environmental implications. The aquaculture value chain in the context of climate change and their implication for practice is further investigated, and the strategies necessary for an improved implementation of resilient aquaculture system in Kenya is examined. Data for the study are collected from interviews, questionnaires, two workshops and document analysis. Despite acclaimed nutritional benefit of fish consumption in Kenya, poor management of effluents enriched with nitrogen, phosphorus, organic matter, and suspended solids has implications not just on the ecosystem, goods, and services, but is also potential source of resource-use conflicts especially in downstream communities and operators in the livestock, horticulture, and industrial sectors. The study concluded that aquaculture focuses on future orientation, climate resilient infrastructure, appropriate site selection and invest on biosafety as the key sustainable strategies against climate hazards.

Keywords: aquaculture, resilience, environment, strategies, Kenya

Procedia PDF Downloads 152
4956 Effective Water Purification by Impregnated Carbon Nanotubes

Authors: Raviteja Chintala

Abstract:

Water shortage in many areas of the world have predominantly increased the demand for efficient methods involved in the production of drinking water, So purification of water invoking cost effective and efficient methods is a challenging field of research. In this regard, Reverse osmosis membrane desalination of both seawater and inland brackish water is currently being deployed in various locations around the world. In the present work an attempt is made to integrate these existing technologies with novel method, Wherein carbon nanotubes at the lab scale are prepared which further replace activated carbon tubes being used traditionally. This has proven to enhance the efficiency of the water filter, Effectively neutralising most of the organic impurities. Furthermore, This ensures the reduction in TDS. Carbon nanotubes have wide range in scope of applications such as composite reinforcements, Field emitters, Sensors, Energy storage and energy conversion devices and catalysts support phases, Because of their unusual mechanical, Electrical, Thermal and structural properties. In particular, The large specific surface area, as well as the high chemical and thermal stability, Makes carbon nanotube an attractive adsorbent in waste water treatment. Carbon nanotubes are effective in eliminating these harmful media from water as an adsorbent. In this work, Candle soot method has been incorporated for the preparation of carbon nanotubes and mixed with activated charcoal in different compositions. The effect of composition change is monitored by using TDS measuring meter. As the composition of Nano carbon increases, The TDS of the water gradually decreases. In order to enhance the life time for carbon filter, Nano tubes are provided with larger surface area.

Keywords: TDS (Total Dissolved Solids), carbon nanotubes, water, candle soot

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4955 Crab Shell Waste Chitosan-Based Thin Film for Acoustic Sensor Applications

Authors: Maydariana Ayuningtyas, Bambang Riyanto, Akhiruddin Maddu

Abstract:

Industrial waste of crustacean shells, such as shrimp and crab, has been considered as one of the major issues contributing to environmental pollution. The waste processing mechanisms to form new, practical substances with added value have been developed. Chitosan, a derived matter from chitin, which is obtained from crab and shrimp shells, performs prodigiously in broad range applications. A chitosan composite-based diaphragm is a new inspiration in fiber optic acoustic sensor advancement. Elastic modulus, dynamic response, and sensitivity to acoustic wave of chitosan-based composite film contribute great potentials of organic-based sound-detecting material. The objective of this research was to develop chitosan diaphragm application in fiber optic microphone system. The formulation was conducted by blending 5% polyvinyl alcohol (PVA) solution with dissolved chitosan at 0%, 1% and 2% in 1:1 ratio, respectively. Composite diaphragms were characterized for the morphological and mechanical properties to predict the desired acoustic sensor sensitivity. The composite with 2% chitosan indicated optimum performance with 242.55 µm thickness, 67.9% relative humidity, and 29-76% light transmittance. The Young’s modulus of 2%-chitosan composite material was 4.89×104 N/m2, which generated the voltage amplitude of 0.013V and performed sensitivity of 3.28 mV/Pa at 1 kHz. Based on the results above, chitosan from crustacean shell waste can be considered as a viable alternative material for fiber optic acoustic sensor sensing pad development. Further, the research in chitosan utilisation is proposed as novel optical microphone development in anthropogenic noise controlling effort for environmental and biodiversity conservation.

Keywords: acoustic sensor, chitosan, composite, crab shell, diaphragm, waste utilisation

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4954 Self-Reliant Peer Learning for Nursing Students

Authors: U.-B. Schaer, M. Wehr, R. Hodler

Abstract:

Background: Most nursing students require more training time for necessary nursing skills than defined by nursing schools curriculum to acquire basic nursing skills. Given skills training lessons are too brief to enable effective student learning, meaning in-depth skills practice and repetition various learning steps. This increases stress levels and the pressure to succeed for a nursing student with slower learning capabilities. Another possible consequence is that nursing students are less prepared in the required skills for future clinical practice. Intervention: The Bern College of Higher Education of Nursing, Switzerland, started the independent peer practice learning program in 2012. A concept was developed which defines specific aims and content as well as student’s rights and obligations. Students enlist beforehand and order the required materials. They organize themselves and train in small groups in allocated training location in the area of Learning Training and Transfer (LTT). During the peer practice, skills and knowledge can be repeatedly trained and reflected in the peer groups without the presence of a tutor. All invasive skills are practiced only on teaching dummies. This allows students to use all their potential. The students may access learning materials as literature and their own student notes. This allows nursing students to practice their skills and to deepen their knowledge on corresponding with their own learning rate. Results: Peer group discussions during the independent peer practice learning support the students in gaining certainty and confidence in their knowledge and skills. This may improve patient safety in future daily care practice. Descriptive statics show that the number of students who take advantage of the independent peer practice learning increased continuously (2012-2018). It has to be mentioned that in 2012, solely students of the first semester attended the independent peer practice learning program, while in 2018 over one-third of the participating students were in their fifth semester and final study year. It is clearly visible that the demand for independent peer practice learning is increasing. This has to be considered in the development of future teaching curricula.

Keywords: learning program, nursing students, peer learning, skill training

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4953 Evaluation of the Discoloration of Methyl Orange Using Black Sand as Semiconductor through Photocatalytic Oxidation and Reduction

Authors: P. Acosta-Santamaría, A. Ibatá-Soto, A. López-Vásquez

Abstract:

Organic compounds in wastewaters coming from textile and pharmaceutical industry generated multiple harmful effects on the environment and the human health. One of them is the methyl orange (MeO), an azoic dye considered to be a recalcitrant compound. The heterogeneous photocatalysis emerges as an alternative for treating this type of hazardous compounds, through the generation of OH radicals using radiation and a semiconductor oxide. According to the author’s knowledge, catalysts such as TiO2 doped with metals show high efficiency in degrading MeO; however, this presents economic limitations on industrial scale. Black sand can be considered as a naturally doped catalyst because in its structure is common to find compounds such as titanium, iron and aluminum oxides, also elements such as zircon, cadmium, manganese, etc. This study reports the photocatalytic activity of the mineral black sand used as semiconductor in the discoloration of MeO by oxidation and reduction photocatalytic techniques. For this, magnetic composites from the mineral were prepared (RM, M1, M2 and NM) and their activity were tested through MeO discoloration while TiO2 was used as reference. For the fractions, chemical, morphological and structural characterizations were performed using Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM-EDX), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) analysis. M2 fraction showed higher MeO discoloration (93%) in oxidation conditions at pH 2 and it could be due to the presence of ferric oxides. However, the best result to reduction process was using M1 fraction (20%) at pH 2, which contains a higher titanium percentage. In the first process, hydrogen peroxide (H2O2) was used as electron donor agent. According to the results, black sand mineral can be used as natural semiconductor in photocatalytic process. It could be considered as a photocatalyst precursor in such processes, due to its low cost and easy access.

Keywords: black sand mineral, methyl orange, oxidation, photocatalysis, reduction

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4952 Ultrasonic Treatment of Baker’s Yeast Effluent

Authors: Emine Yılmaz, Serap Fındık

Abstract:

Baker’s yeast industry uses molasses as a raw material. Molasses is end product of sugar industry. Wastewater from molasses processing presents large amount of coloured substances that give dark brown color and high organic load to the effluents. The main coloured compounds are known as melanoidins. Melanoidins are product of Maillard reaction between amino acid and carbonyl groups in molasses. Dark colour prevents sunlight penetration and reduces photosynthetic activity and dissolved oxygen level of surface waters. Various methods like biological processes (aerobic and anaerobic), ozonation, wet air oxidation, coagulation/flocculation are used to treatment of baker’s yeast effluent. Before effluent is discharged adequate treatment is imperative. In addition to this, increasingly stringent environmental regulations are forcing distilleries to improve existing treatment and also to find alternative methods of effluent management or combination of treatment methods. Sonochemical oxidation is one of the alternative methods. Sonochemical oxidation employs ultrasound resulting in cavitation phenomena. In this study, decolorization of baker’s yeast effluent was investigated by using ultrasound. Baker’s yeast effluent was supplied from a factory which is located in the north of Turkey. An ultrasonic homogenizator used for this study. Its operating frequency is 20 kHz. TiO2-ZnO catalyst has been used as sonocatalyst. The effects of molar proportion of TiO2-ZnO, calcination temperature and time, catalyst amount were investigated on the decolorization of baker’s yeast effluent. The results showed that prepared composite TiO2-ZnO with 4:1 molar proportion treated at 700°C for 90 min provides better result. Initial decolorization rate at 15 min is 3% without catalyst, 14,5% with catalyst treated at 700°C for 90 min respectively.

Keywords: baker’s yeast effluent, decolorization, sonocatalyst, ultrasound

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4951 Establishing a Computational Screening Framework to Identify Environmental Exposures Using Untargeted Gas-Chromatography High-Resolution Mass Spectrometry

Authors: Juni C. Kim, Anna R. Robuck, Douglas I. Walker

Abstract:

The human exposome, which includes chemical exposures over the lifetime and their effects, is now recognized as an important measure for understanding human health; however, the complexity of the data makes the identification of environmental chemicals challenging. The goal of our project was to establish a computational workflow for the improved identification of environmental pollutants containing chlorine or bromine. Using the “pattern. search” function available in the R package NonTarget, we wrote a multifunctional script that searches mass spectral clusters from untargeted gas-chromatography high-resolution mass spectrometry (GC-HRMS) for the presence of spectra consistent with chlorine and bromine-containing organic compounds. The “pattern. search” function was incorporated into a different function that allows the evaluation of clusters containing multiple analyte fragments, has multi-core support, and provides a simplified output identifying listing compounds containing chlorine and/or bromine. The new function was able to process 46,000 spectral clusters in under 8 seconds and identified over 150 potential halogenated spectra. We next applied our function to a deidentified dataset from patients diagnosed with primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and healthy controls. Twenty-two spectra corresponded to potential halogenated compounds in the PSC and PBC dataset, including six significantly different in PBC patients, while four differed in PSC patients. We have developed an improved algorithm for detecting halogenated compounds in GC-HRMS data, providing a strategy for prioritizing exposures in the study of human disease.

Keywords: exposome, metabolome, computational metabolomics, high-resolution mass spectrometry, exposure, pollutants

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4950 A Study on Soil Micro-Arthropods Assemblage in Selected Plantations in The Nilgiris, Tamilnadu

Authors: J. Dharmaraj, C. Gunasekaran

Abstract:

Invertebrates are the reliable ecological indicators of disturbance of the forest ecosystems and they respond to environment changes more quickly than other fauna. Among these the terrestrial invertebrates are vital to functioning ecosystems, contributing to processes such as decomposition, nutrient cycling and soil fertility. The natural ecosystems of the forests have been subject to various types of disturbances, which lead to decline of flora and fauna. The comparative diversity of micro-arthropods in natural forest, wattle plantation and eucalyptus plantations were studied in Nilgiris. The study area was divided in to five major sites (Emerald (Site-I), Thalaikundha (Site-II), Kodapmund (Site-III), Aravankad (Site-IV), Kattabettu (Site-V). The research was conducted during period from March 2014 to August 2014. The leaf and soil samples were collected and isolated by using Berlese funnel extraction methods. Specimens were isolated and identified according to their morphology (Balogh 1972). In the present study results clearly showed the variation in soil pH, NPK (Major Nutrients) and organic carbon among the study sites. The chemical components of the leaf litters of the plantation decreased the diversity of micro-arthropods and decomposition rate leads to low amount of carbon and other nutrients present in the soil. Moreover eucalyptus and wattle plantations decreases the availability of the ground water source to other plantations and micro-arthropods and hences affects the soil fertility. Hence, the present study suggests to minimize the growth of wattle and eucalyptus tree plantations in the natural areas which may help to reduce the decline of forests.

Keywords: micro-arthropods, assemblage, berlese funnel, morphology, NPK, nilgiris

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4949 A Bicycle Based Model of Prehospital Care Implanted in Northeast of the Brazil: Initial Experience

Authors: Odaleia de O. Farias, Suzelene C. Marinho, Ecleidson B. Fragoso, Daniel S. Lima, Francisco R. S. Lira, Lara S. Araújo, Gabriel dos S. D. Soares

Abstract:

In populous cities, prehospital care services that use vehicles alternative to ambulances are needed in order to reduce costs and improve response time to occurrences in areas with large concentration of people, such as leisure and tourism spaces. In this context, it was implanted a program called BIKE VIDA, that is innovative quick access and assistance program. The aim of this study is to describe the implantation and initial profile of occurrences performed by an urgency/emergency pre-hospital care service through paramedics on bicycles. It is a cross-sectional, descriptive study carried out in the city of Fortaleza, Ceara, Brazil. The data included service records from July to August 2017. Ethical aspects were respected. The service covers a perimeter of 4.5 km, divided into three areas with perimeter of 1.5 km for each paramedic, attending from 5 am to 9 pm. Materials transported by bicycles include External Automated Defibrillator - DEA, portable oxygen, oximeter, cervical collar, stethoscope, sphygmomanometer, dressing and immobilization materials and personal protective equipment. Occurrences are requested directly by calling the emergency number 192 or through direct approach to the professional. In the first month of the program, there were 93 emergencies/urgencies, mainly in the daytime period (71,0%), in males (59,7%), in the age range of 26 to 45 years (46,2%). The main nature was traumatic incidents (53.3%). Most of the cases (88,2%) did not require ambulance transport to the hospital, and there were two deaths. Pre-hospital service through bicycles is an innovative strategy in Brazil and has shown to be promising in terms of reducing costs and improving the quality of the services offered.

Keywords: emergency, response time, prehospital care, urgency

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4948 Investigating the Molecular Behavior of H₂O in Caso 4 -2h₂o Two-Dimensional Nanoscale System

Authors: Manal Alhazmi, Artem Mishchenko

Abstract:

A molecular fluids' behavior and interaction with other materials at the nanoscale is a complex process. Nanoscale fluids behave so differently than macroscale fluids and interact with other materials in unique ways. It is, therefore, feasible to understand the molecular behavior of H₂O in such two-dimensional nanoscale systems by studying (CaSO4-2H2O), commonly known as gypsum. In the present study, spectroscopic measurements on a 2D structure of exfoliated gypsum crystals are carried out by Raman and IR spectroscopy. An array of gypsum flakes with thicknesses ranging from 8nm to 100nm were observed and analyzed for their Raman and IR spectrum. Water molecules stretching modes spectra lines were also measured and observed in nanoscale gypsum flakes and compared with those of bulk crystals. CaSO4-2H2O crystals have Raman and infrared bands at 3341 cm-1 resulting from the weak hydrogen bonds between the water molecules. This internal vibration of water molecules, together with external vibrations with other atoms, are responsible for these bands. There is a shift of about 70 cm-1 In the peak position of thin flakes with respect to the bulk crystal, which is a result of the different atomic arrangement from bulk to thin flake on the nano scale. An additional peak was observed in Raman spectra around 2910-3137 cm⁻¹ in thin flakes but is missing in bulk crystal. This additional peak is attributed to a combined mode of water internal (stretching mode at 3394cm⁻¹) and external vibrations. In addition to Raman and infra- red analysis of gypsum 2D structure, electrical measurements were conducted to reveal the water molecules transport behavior in such systems. Electrical capacitance of the fabricated device is measured and found to be (0.0686 *10-12) F, and the calculated dielectric constant (ε) is (12.26).

Keywords: gypsum, infra-red spectroscopy, raman spectroscopy, H₂O behavior

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4947 Soil Reinforcement by Stone Columns

Authors: Saou Mohamed Amine

Abstract:

The construction industry has been identified as a user of substantial amount of materials and energy resources that has an enormous impact on environment. The energy efficient in refurbishment project is being considered as one of the approaches to achieve sustainability in construction industry. The increasing concern for environment has made building owners and designers to incorporate the energy efficiency features into their building projects.

Keywords: construction industry, design team attributes, energy efficient performance, refurbishment projects characteristics

Procedia PDF Downloads 417
4946 Cationic Copolymer-Functionalized Nanodiamonds Stabilizes Silver Nanoparticles with Dual Antibacterial Activity and Lower Cytotoxicity

Authors: Weiwei Cao, Xiaodong Xing

Abstract:

In order to effectively resolve the microbial pollution and contamination, synthetic nano-antibacterial materials are widely used in daily life. Among them, nanodiamonds (NDs) have recently been demonstrated to hold promise as useful materials in biomedical applications due to their high specific surface area and biocompatibility. In this work, the copolymer, poly(4-vinylpyridine-co-2-hydroxyethyl methacrylate) was applied for the surface functionalization of NDs to produce the quaternized poly(4-vinylpyridine-co-2-hydroxyethyl methacrylate)-functionalized NDs (QNDs). Then, QNDs were used as a substrate for silver nanoparticles (AgNPs) to produce a QND@Ag hybrid. The composition and morphology of the resultant nanostructures were confirmed by Fourier transform infrared spectra (FT-IR), transmission electron microscope (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The mass fraction of AgNPs in the nanocomposites was about 35.7%. The antibacterial performances of the prepared nanocomposites were evaluated with Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus by minimum inhibitory concentration (MIC), inhibition zone testing and time-kill study. As a result, due to the synergistic antibacterial activity of QND and AgNPs, this hybrid showed substantially higher antibacterial activity than QND and polyvinyl pyrrolidone (PVP)-stabilized AgNPs, and the AgNPs on QND@Ag were more stable than the Ag NPs on PVP, resulting in long-term antibacterial effects. More importantly, this hybrid showed excellent water solubility and low cytotoxicity, suggesting the great potential application in biomedical applications. The present work provided a simple strategy that successfully turned NDs into nanosized antibiotics with simultaneous superior stability and biocompatibility, which would broaden the applications of NDs and advance the development of novel antibacterial agents.

Keywords: cationic copolymer, nanodiamonds, silver nanoparticles, dual antibacterial activity, lower cytotoxicity

Procedia PDF Downloads 119
4945 Thermo-Mechanical Processing Scheme to Obtain Micro-Duplex Structure Favoring Superplasticity in an As-Cast and Homogenized Medium Alloyed Nickel Base Superalloy

Authors: K. Sahithya, I. Balasundar, Pritapant, T. Raghua

Abstract:

Ni-based superalloy with a nominal composition Ni-14% Cr-11% Co-5.8% Mo-2.4% Ti-2.4% Nb-2.8% Al-0.26 % Fe-0.032% Si-0.069% C (all in wt %) is used as turbine discs in a variety of aero engines. Like any other superalloy, the primary processing of the as-cast superalloy poses a major challenge due to its complex alloy chemistry. The challenge was circumvented by characterizing the different phases present in the material, optimizing the homogenization treatment, identifying a suitable thermomechanical processing window using dynamic materials modeling. The as-cast material was subjected to homogenization at 1200°C for a soaking period of 8 hours and quenched using different media. Water quenching (WQ) after homogenization resulted in very fine spherical γꞌ precipitates of sizes 30-50 nm, whereas furnace cooling (FC) after homogenization resulted in bimodal distribution of precipitates (primary gamma prime of size 300nm and secondary gamma prime of size 5-10 nm). MC type primary carbides that are stable till the melting point of the material were found in both WQ and FC samples. Deformation behaviour of both the materials below (1000-1100°C) and above gamma prime solvus (1100-1175°C) was evaluated by subjecting the material to series of compression tests at different constant true strain rates (0.0001/sec-1/sec). An in-detail examination of the precipitate dislocation interaction mechanisms carried out using TEM revealed precipitate shearing and Orowan looping as the mechanisms governing deformation in WQ and FC, respectively. Incoherent/semi coherent gamma prime precipitates in the case of FC material facilitates better workability of the material, whereas the coherent precipitates in WQ material contributed to higher resistance to deformation of the material. Both the materials exhibited discontinuous dynamic recrystallization (DDRX) above gamma prime solvus temperature. The recrystallization kinetics was slower in the case of WQ material. Very fine grain boundary carbides ( ≤ 300 nm) retarded the recrystallisation kinetics in WQ. Coarse carbides (1-5 µm) facilitate particle stimulated nucleation in FC material. The FC material was cogged (primary hot working) 1120˚C, 0.03/sec resulting in significant grain refinement, i.e., from 3000 μm to 100 μm. The primary processed material was subjected to intensive thermomechanical deformation subsequently by reducing the temperature by 50˚C in each processing step with intermittent heterogenization treatment at selected temperatures aimed at simultaneous coarsening of the gamma prime precipitates and refinement of the gamma matrix grains. The heterogeneous annealing treatment carried out, resulted in gamma grains of 10 μm and gamma prime precipitates of 1-2 μm. Further thermo mechanical processing of the material was carried out at 1025˚C to increase the homogeneity of the obtained micro-duplex structure.

Keywords: superalloys, dynamic material modeling, nickel alloys, dynamic recrystallization, superplasticity

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4944 Effect of Microstructure on Transition Temperature of Austempered Ductile Iron (ADI)

Authors: A. Ozel

Abstract:

The ductile to brittle transition temperature is a very important criterion that is used for selection of materials in some applications, especially in low-temperature conditions. For that reason, in this study transition temperature of as-cast and austempered unalloyed ductile iron in the temperature interval from -60 to +100 degrees C have been investigated. The microstructures of samples were examined by light microscope. The impact energy values obtained from the experiments were found to depend on the austempering time and temperature.

Keywords: Austempered Ductile Iron (ADI), Charpy test, microstructure, transition temperature

Procedia PDF Downloads 491
4943 Development of New Localized Surface Plasmon Resonance Interfaces Based on ITO Au NPs/ Polymer for Nickel Detection

Authors: F. Z. Tighilt, N. Belhaneche-Bensemra, S. Belhousse, S. Sam, K. Lasmi, N. Gabouze

Abstract:

Recently, the gold nanoparticles (Au NPs) became an active multidisciplinary research topic. First, Au thin films fabricated by alkylthiol-functionalized Au NPs were found to have vapor sensitive conductivities, they were hence widely investigated as electrical chemiresistors for sensing different vapor analytes and even organic molecules in aqueous solutions. Second, Au thin films were demonstrated to have speciallocalized surface plasmon resonances (LSPR), so that highly ordered 2D Au superlattices showed strong collective LSPR bands due to the near-field coupling of adjacent nanoparticles and were employed to detect biomolecular binding. Particularly when alkylthiol ligands were replaced by thiol-terminated polymers, the resulting polymer-modified Au NPs could be readily assembled into 2D nanostructures on solid substrates. Monolayers of polystyrene-coated Au NPs showed typical dipolar near-field interparticle plasmon coupling of LSPR. Such polymer-modified Au nanoparticle films have an advantage that the polymer thickness can be feasibly controlled by changing the polymer molecular weight. In this article, the effect of tin-doped indium oxide (ITO) coatings on the plasmonic properties of ITO interfaces modified with gold nanostructures (Au NSs) is investigated. The interest in developing ITO overlayers is multiple. The presence of a con-ducting ITO overlayer creates a LSPR-active interface, which can serve simultaneously as a working electrode in an electro-chemical setup. The surface of ITO/ Au NPs contains hydroxyl groups that can be used to link functional groups to the interface. Here the covalent linking of nickel /Au NSs/ITO hybrid LSPR platforms will be presented.

Keywords: conducting polymer, metal nanoparticles (NPs), LSPR, poly (3-(pyrrolyl)–carboxylic acid), polypyrrole

Procedia PDF Downloads 259
4942 Rule of Natural Synthetic Chemical on Lead Immobilization in Polluted Sandy Soils

Authors: Saud S. AL Oud

Abstract:

Soil contamination can have dire consequences, such as loss of ecosystem and agricultural productivity, diminished food chain quality, tainted water resources, economic loss, and human and animal illness. In recent years, attention has focused on the development of in situ immobilization methods that are generally less expensive and disruptive to the natural landscape, hydrology, and ecosystems than are conventional excavation treatments, and disposal methods. Soft, inexpensive, and efficient agents were used in the present research to immobilize Pb in polluted sandy soil. Five agents, either naturally occurring or chemically prepared, were used for this purpose. These agents include; iron ore (72% Fe2O3), cement, a mixture of calcite and shale rich in aluminum (CASH), and two chemically prepared amorphous materials of Al- and Fe-gel. These agents were selected due to their ability to specifically adsorb heavy metals onto their surface OH functional groups, which provide permanent immobilization of metal pollutants and reduce the fraction that is potentially mobile or bioavailable. The efficiency of these agents in immobilizing Pb were examined in a laboratory experiment, in which two rates (0.5 and 1.0 %) of tested agents were added to the polluted soils containing total contents of Pb ranging from 17.4-49.8 mg/kg. The results show that all immobilizing agents were succeed in minimizing the mobile form of Pb as extracted by 0.5 N HNO3. The extracted Pb decreased with increasing addition rate of immobilizing agents. At addition rate of 0.5%, HNO3 extractable-Pb varied widely depending on the agents type and were found to represent 21-67% of the initial values. All agents were able to reduce mobile Pb to levels lower than that (2.0 mg/kg) reported for non polluted soil, particularly for soils had initials of mobile Pb less than 10 mg/kg. Both iron oxide and CASH had the highest efficiency in immobilizing Pb, followed by cement, then amorphous materials of Fe and Al hydroxides.

Keywords: soil, synthetic chemical, lead, immobilization, polluted

Procedia PDF Downloads 226
4941 Distribution and Historical Trends of PAHs Deposition in Recent Sediment Cores of the Imo River, SE Nigeria

Authors: Miranda I. Dosunmu, Orok E. Oyo-Ita, Inyang O. Oyo-Ita

Abstract:

Polycyclic aromatic hydrocarbons (PAHs) are a class of priority listed organic pollutants due to their carcinogenicity, mutagenity, acute toxicity and persistency in the environment. The distribution and historical changes of PAHs contamination in recent sediment cores from the Imo River were investigated using gas chromatography coupled with mass spectrometer. The concentrations of total PAHs (TPAHs) ranging from 402.37 ng/g dry weight (dw) at the surface layer of the Estuary zone (ESC6; 0-5 cm) to 92,388.59 ng/g dw at the near surface layer of the Afam zone (ASC5; 5-10 cm) indicate that PAHs contamination was localized not only between sample sites but also within the same cores. Sediment-depth profiles for the four (Afam, Mangrove, Estuary and illegal Petroleum refinery) cores revealed irregular distribution patterns in the TPAH concentrations except the fact that these levels became maximized at the near surface layers (5-10 cm) corresponding to a geological time-frame of about 1996-2004. This time scale coincided with the period of intensive bunkering and oil pipeline vandalization by the Niger Delta militant groups. Also a general slight decline was found in the TPAHs levels from near the surface layers (5-10 cm) to the most recent top layers (0-5 cm) of the cores, attributable to the recent effort by the Nigerian government in clamping down the illegal activity of the economic saboteurs. Therefore, the recent amnesty period granted to the militant groups should be extended. Although mechanism of perylene formation still remains enigmatic, examination of its distributions down cores indicates natural biogenic, pyrogenic and petrogenic origins for the compound at different zones. Thus, the characteristic features of the Imo River environment provide a means of tracing diverse origins for perylene.

Keywords: perylene, historical trend, distribution, origin, Imo River

Procedia PDF Downloads 240
4940 Photocatalytic Degradation of Methylene Blue Dye Using Cuprous Oxide/Graphene Nanocomposite

Authors: Bekan Bogale, Tsegaye Girma Asere, Tilahun Yai, Fekadu Melak

Abstract:

Aims: To study photocatalytic degradation of methylene blue dye on cuprous oxide/graphene nanocomposite. Background: Cuprous oxide (Cu2O) nanoparticles are among the metal oxides that demonstrated photocatalytic activity. However, the stability of Cu2O nanoparticles due to the fast recombination rate of electron/hole pairs remains a significant challenge in their photocatalytic applications. This, in turn, leads to mismatching of the effective bandgap separation, tending to reduce the photocatalytic activity of the desired organic waste (MB). To overcome these limitations, graphene has been combined with cuprous oxides, resulting in cuprous oxide/graphene nanocomposite as a promising photocatalyst. Objective: In this study, Cu2O/graphene nanocomposite was synthesized and evaluated for its photocatalytic performance of methylene blue (MB) dye degradation. Method: Cu2O/graphene nanocomposites were synthesized from graphite powder and copper nitrate using the facile sol-gel method. Batch experiments have been conducted to assess the applications of the nanocomposites for MB degradation. Parameters such as contact time, catalyst dosage, and pH of the solution were optimized for maximum MB degradation. The prepared nanocomposites were characterized by using UV-Vis, FTIR, XRD, and SEM. The photocatalytic performance of Cu2O/graphene nanocomposites was compared against Cu2O nanoparticles for cationic MB dye degradation. Results: Cu2O/graphene nanocomposite exhibits higher photocatalytic activity for MB degradation (with a degradation efficiency of 94%) than pure Cu2O nanoparticles (67%). This has been accomplished after 180 min of irradiation under visible light. The kinetics of MB degradation by Cu2O/graphene composites can be demonstrated by the second-order kinetic model. The synthesized nanocomposite can be used for more than three cycles of photocatalytic MB degradation. Conclusion: This work indicated new insights into Cu2O/graphene nanocomposite as high-performance in photocatalysis to degrade MB, playing a great role in environmental protection in relation to MB dye.

Keywords: methylene blue, photocatalysis, cuprous oxide, graphene nanocomposite

Procedia PDF Downloads 173
4939 Improvement of the Geometric of Dental Bridge Framework through Automatic Program

Authors: Rong-Yang Lai, Jia-Yu Wu, Chih-Han Chang, Yung-Chung Chen

Abstract:

The dental bridge is one of the clinical methods of the treatment for missing teeth. The dental bridge is generally designed for two layers, containing the inner layer of the framework(zirconia) and the outer layer of the porcelain-fused to framework restorations. The design of a conventional bridge is generally based on the antagonist tooth profile so that the framework evenly indented by an equal thickness from outer contour. All-ceramic dental bridge made of zirconia have well demonstrated remarkable potential to withstand a higher physiological occlusal load in posterior region, but it was found that there is still the risk of all-ceramic bridge failure in five years. Thus, how to reduce the incidence of failure is still a problem to be solved. Therefore, the objective of this study is to develop mechanical designs for all-ceramic dental bridges framework by reducing the stress and enhancing fracture resistance under given loading conditions by finite element method. In this study, dental design software is used to design dental bridge based on tooth CT images. After building model, Bi-directional Evolutionary Structural Optimization (BESO) Method algorithm implemented in finite element software was employed to analyze results of finite element software and determine the distribution of the materials in dental bridge; BESO searches the optimum distribution of two different materials, namely porcelain and zirconia. According to the previous calculation of the stress value of each element, when the element stress value is higher than the threshold value, the element would be replaced by the framework material; besides, the difference of maximum stress peak value is less than 0.1%, calculation is complete. After completing the design of dental bridge, the stress distribution of the whole structure is changed. BESO reduces the peak values of principle stress of 10% in outer-layer porcelain and avoids producing tensile stress failure.

Keywords: dental bridge, finite element analysis, framework, automatic program

Procedia PDF Downloads 271
4938 Kaolinite-Assisted Microencapsulation of Octodecane for Thermal Energy Storage

Authors: Ting Pan, Jiacheng Wang, Pengcheng Lin, Ying Chen, Songping Mo

Abstract:

Phase change materials (PCMs) are widely used in latent heat thermal energy storage because of their good properties such as high energy storage density and constant heat-storage/release temperature. Microencapsulation techniques can prevent PCMs from leaking during the liquid-solid phase transition and enhance thermal properties. This technique has been widely applied in architectural materials, thermo-regulated textiles, aerospace fields, etc. One of the most important processes during the synthesis of microcapsules is to form a stable emulsion of the PCM core and reactant solution for the formation of the shell of the microcapsules. The use of surfactants is usually necessary for the formation of a stable emulsion system because of the difference in hydrophilia/lipophilicity of the PCM and the solvent. Unfortunately, the use of surfactants may cause pollution to the environment. In this study, modified kaolinite was used as an emulsion stabilizer for the microencapsulation of octodecane as PCM. Microcapsules were synthesized by phase inversion emulsification method, and the shell of polymethyl methacrylate (PMMA) was formed through free radical polymerization. The morphologies, crystalloid phase, and crystallization properties of microcapsules were investigated using scanning electron microscopy (SEM), X-ray diffractometer (XRD), and Fourier transforms infrared spectrometer (FTIR). The thermal properties and thermal stability were investigated by a differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TG). The FT-IR, XRD results showed that the octodecane was well encapsulated in the PMMA shell. The SEM results showed that the microcapsules were spheres with an average size of about 50-100nm. The DSC results indicated that the latent heat of the microcapsules was 152.64kJ/kg and 164.23kJ/kg. The TG results confirmed that the microcapsules had good thermal stability due to the PMMA shell. Based on the results, it can be concluded that the modified kaolinite can be used as an emulsifier for the synthesis of PCM microcapsules, which is valid for reducing part of the possible pollution caused by the utilization of surfactants.

Keywords: kaolinite, microencapsulation, PCM, thermal energy storage

Procedia PDF Downloads 117