Search results for: similarity solution

Authors: J. Ritonja, R. Brezovnik, M. Petrun, B. Polajžer

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Many modern synchronous generators in power systems are extremely weakly damped. The reasons are cost optimization of the machine building and introduction of the additional control equipment into power systems. Oscillations of the synchronous generators and related stability problems of the power systems are harmful and can lead to failures in operation and to damages. The only useful solution to increase damping of the unwanted oscillations represents the implementation of the power system stabilizers. Power system stabilizers generate the additional control signal which changes synchronous generator field excitation voltage. Modern power system stabilizers are integrated into static excitation systems of the synchronous generators. Available commercial power system stabilizers are based on linear control theory. Due to the nonlinear dynamics of the synchronous generator, current stabilizers do not assure optimal damping of the synchronous generator’s oscillations in the entire operating range. For that reason the use of the robust power system stabilizers which are convenient for the entire operating range is reasonable. There are numerous robust techniques applicable for the power system stabilizers. In this paper the use of sliding mode control for synchronous generator stability improvement is studied. On the basis of the sliding mode theory, the robust power system stabilizer was developed. The main advantages of the sliding mode controller are simple realization of the control algorithm, robustness to parameter variations and elimination of disturbances. The advantage of the proposed sliding mode controller against conventional linear controller was tested for damping of the synchronous generator oscillations in the entire operating range. Obtained results show the improved damping in the entire operating range of the synchronous generator and the increase of the power system stability. The proposed study contributes to the progress in the development of the advanced stabilizer, which will replace conventional linear stabilizers and improve damping of the synchronous generators.

Keywords: control theory, power system stabilizer, robust control, sliding mode control, stability, synchronous generator

Procedia PDF Downloads 199

Authors: A. Luli, A. Santona

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It is rare for individuals that are involved in a relationship to think about the possibility of having procreation problems in the near present or in the future. However, infertility is a condition that affects millions of people all around the world. Often, infertile individuals have to deal with experiences of psychological, relational and social problems. In these cases, they have to review their choices and take into consideration, if it is necessary, new ones. Different studies have examined the different decisions that infertile individuals have to go through dealing with infertility and its treatment, but none of them is focused on the decision-making style used by infertile individuals to solve their problem and on the factors that influences it. The aim of this paper is to define the style of decision-making used by infertile persons to give a solution to the ‘problem’ and the potential predictive role of the attachment and of the dyadic adjustment. The total sample is composed by 251 participants, divided in two groups: the experimental group composed by 114 participants, 62 males and 52 females, age between 25 and 59 years, and the control group composed by 137 participants, 65 males and 72 females, age between 22 and 49 years. The battery of instruments used is composed by: the General Decision Making Style (GDMS), the Experiences in Close Relationships Questionnaire Revised (ECR-R), Dyadic Adjustment Scale (DAS), and the Symptom Checklist-90-R (SCL-90-R). The results from the analysis of the samples showed a prevalence of the rational decision-making style for both males and females. No significant statistical difference was found between the experimental and control group. Also the analyses showed a significant statistical relationship between the decision making styles and the adult attachment styles for both males and females. In this case, only for males, there was a significant statistical difference between the experimental and the control group. Another significant statistical relationship was founded between the decision making styles and the adjustment scales for both males and females. Also in this case, the difference between the two groups was founded to be significant only of males. These results contribute to enrich the literature on the subject of decision-making styles in infertile individuals, showing also the predictive role of the attachment styles and the adjustment, confirming in this was the few results in the literature.

Keywords: adjustment, attachment, decision-making style, infertility

Procedia PDF Downloads 305

Authors: Laurent Pitteloud, Jörg Meier

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Piled raft foundations represent an efficient and reliable technique for transferring high vertical and horizontal loads to the subsoil. Piled raft foundations were success­fully implemented for several high-rise buildings world­wide over the last decades. For the structural design of this foundation type the stiffnesses of both the piles and the raft have to be deter­mined for the static (e.g. dead load, live load) and the dynamic load cases (e.g. earthquake). In this context the question often arises, to which proportion wind loads are to be considered as dynamic loads. Usually a piled raft foundation has to be monitored in order to verify the design hypotheses. As an additional benefit, the analysis of this monitoring data may lead to a better under­standing of the behaviour of this foundation type for future projects in similar subsoil conditions. In case the measurement frequency is high enough, one may also draw conclusions on the effect of wind loading on the piled raft foundation. For a 41-storey office building in Basel, Switzerland, the preliminary design showed that a piled raft foundation was the best solution to satisfy both design requirements, as well as economic aspects. A high-frequency monitoring of the foundation including pile loads, vertical stresses under the raft, as well as pore water pressures was performed over 5 years. In windy situations the analysis of the measure­ments shows that the pile load increment due to wind consists of a static and a cyclic load term. As piles and raft react with different stiffnesses under static and dynamic loading, these measure­ments are useful for the correct definition of stiffnesses of future piled raft foundations. This paper outlines the design strategy and the numerical modelling of the aforementioned piled raft foundation. The measurement results are presented and analysed. Based on the findings, comments and conclusions on the definition of pile and raft stiffnesses for vertical and wind loading are proposed.

Keywords: design, dynamic, foundation, monitoring, pile, raft, wind load

Procedia PDF Downloads 165

Authors: N. Ismail, O. Thammajinda, U. Thongpanya

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Games-based learning (GBL) has become increasingly important in teaching and learning. This paper explains the first two phases (analysis and design) of a GBL development project, ending up with a prototype design based on students’ and teachers’ perceptions. The two phases are part of a full cycle GBL project aiming to help secondary school students in Thailand in their study of Comprehensive Sex Education (CSE). In the course of the study, we invited 1,152 students to complete questionnaires and interviewed 12 secondary school teachers in focus groups. This paper found that GBL can serve students in their learning about CSE, enabling them to gain understanding of their sexuality, develop skills, including critical thinking skills and interact with others (peers, teachers, etc.) in a safe environment. The objectives of this paper are to outline the development of GBL variables from the research question(s) into the developers’ flow chart, to be responsive to the GBL beneficiaries’ preferences and expectations, and to help in answering the research questions. This paper details the steps applied to generate GBL variables that can feed into a game flow chart to develop a GBL prototype. In our approach, we detailed two models: (1) Game Elements Model (GEM) and (2) Game Object Model (GOM). There are three outcomes of this research – first, to achieve the objectives and benefits of GBL in learning, game design has to start with the research question(s) and the challenges to be resolved as research outcomes. Second, aligning the educational aims with engaging GBL end users (students) within the data collection phase to inform the game prototype with the game variables is essential to address the answer/solution to the research question(s). Third, for efficient GBL to bridge the gap between pedagogy and technology and in order to answer the research questions via technology (i.e. GBL) and to minimise the isolation between the pedagogists “P” and technologist “T”, several meetings and discussions need to take place within the team.

Keywords: games-based learning, engagement, pedagogy, preferences, prototype

Procedia PDF Downloads 148

Authors: K. Sushma Varma, Rajesh Singh

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Non-engineered landfills cause serious environmental damage due to toxic emissions and mobilization of persistent pollutants, organic and inorganic contaminants, as well as soluble metal ions. The available treatment technologies for landfill leachate and solid waste are not effective from an economic, environmental, and social standpoint. The present study assesses the potential of the bioelectrochemical system (BES) integrated with sulfate-reducing bacteria (SRB) in the sustainable treatment and decontamination of landfill wastes. For this purpose, solid waste and landfill leachate collected from different landfill sites were evaluated for long-term treatment using the integrated SRB-BES anaerobic designed bioreactors after pre-treatment. Based on periodic gas composition analysis, physicochemical characterization of the leachate and solid waste, and metal concentration determination, the present system demonstrated significant improvement in volumetric hydrogen production by suppressing methanogenesis. High reduction percentages of Be, Cr, Pb, Cd, Sb, Ni, Cr, COD, and sTOC removal were observed. This mineralization can be attributed to the synergistic effect of ammonia-assisted pre-treatment complexation and microbial sulphide formation. Despite being amended with 0.1N ammonia, the treated leachate level of NO³⁻ was found to be reduced along with SO₄²⁻. This integrated SRB-BES system can be recommended as an eco-friendly solution for landfill reclamation. The BES-treated solid waste was evidently more stabilized, as shown by a five-fold increase in surface area, and potentially useful for leachate immobilization and bio-fortification of agricultural fields. The vector arrangement and magnitude showed similar treatment with differences in magnitudes for both leachate and solid waste. These findings support the efficacy of SRB-BES in the treatment of landfill leachate and solid waste sustainably, inching a step closer to our sustainable development goals. It utilizes low-cost treatment, and anaerobic SRB adapted to landfill sites. This technology may prove to be a sustainable treatment strategy upon scaling up as its outcomes are two-pronged: landfill waste treatment and energy recovery.

Keywords: bio-electrochemical system, leachate /solid waste treatment, landfill leachate, sulfate-reducing bacteria

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Authors: Kabiru Adamu

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The Nigerian electricity industry was deregulated and privatized in 2005 and 2014 in line with global trend and practice. International and multilateral lending institutions advised developing countries, Nigeria inclusive, to adopt deregulation and privatization as part of reforms in their electricity sectors. The ideological basis of these reforms are traceable to neoliberalism. Neoliberalism is an ideology that believes in the supremacy of free market and strong non-interventionist competition law as against government ownership of the electricity market. This ideology became a state practice and a blue print for the deregulation and privatization of the electricity markets in many parts of the world. The blue print was used as a template for the privatization of the Nigerian electricity industry. In this wise, this paper, using documentary analysis and review of academic literatures, examines neoliberalism as an ideology and model of economic governance for the electricity supply industry in Nigeria. The paper examines the origin of the ideology, it features and principles and how it was used as the blue print in designing policies for electricity reforms in both developed and developing countries. The paper found out that there is gap between the ideology in theory and in practice because although the theory is rational in thinking it is difficult to be implemented in practice. The paper argues that the ideology has a mismatched effect and this has made its application in the electricity industry in many developing countries problematic and unsuccessful. In the case of Nigeria, the article argues that the template is also not working. The article concludes that the electricity sectors in Nigeria have failed to develop into competitive market for the benefit of consumers in line with the assumptions and promises of the ideology. The paper therefore recommends the democratization of the electricity sectors in Nigeria through a new system of public ownership as the solution to the failure of the neoliberal policies; but this requires the design of a more democratic and participatory system of ownership with communities and state governments in charge of the administration, running and operation of the sector.

Keywords: electricity, energy governance, neo-liberalism, regulation

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Authors: Sela Adjei

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This paper aims to rationalize the need for media policy implementation and copyright enforcement to address various challenges faced within Ghana’s film industry. After Ghana transitioned to democratic rule in 1992, critics and media professionals advocated a national media policy. This advocacy subsequently resulted in agitation for media deregulation and loosening of grip on state-owned media organizations. The reinstatement of constitutional rule in 1992 paved the way for the state to lax its monopoly of the media within the democratic context of a free market economy. The National Media Commission proposed a media policy and broadcast bill which was presented to parliament but has still not been passed into law. This legislative lapse partly contributed to the influx of unregulated foreign content. Accessible foreign media content subsequently promoted a system of unfair competition that radically undermined locally produced content, putting a generation of thriving film producers out of work. Drawing on reflections from a series of structured interviews, focus group discussions and creative workshops, the findings of this study maintain that the various challenges confronting Ghanaian filmmakers is centred around inadequate funding opportunities, copyright violation and policy implementation issues. Using the film industry structure and value chain analysis, the various challenges faced by the selected film producers were discussed and critically analyzed. A significant aspect of this study is the solution-driven approach adopted in outlining the practical recommendations that will boost the aesthetic, cultural and economic value of Ghanaian film productions. Based on the discussions and conclusions drawn with the various stakeholders within Ghana’s creative industries, the paper makes a strong case for firm state regulation, copyright enforcement and policy implementation to grow Ghana’s film industry.

Keywords: film, value, copyright, media, policy, culture, regulation, economy

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Authors: Virginia Martin Torrejon, Song Hang

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Gelatine foams are widely explored materials due to their biodegradability, biocompatibility, and availability. They exhibit outstanding properties and are currently subject to increasing scientific research due to their potential use in different applications, such as biocompatible cellular materials for biomedical products or biofoams as an alternative to fossil-fuel-derived packaging. Gelatine is a highly surface-active polymer, and its concentrated solutions usually do not require surfactants to achieve low surface tension. Still, anionic surfactants like sodium dodecyl sulfate (SDS) strongly interact with gelatine, impacting its viscosity and rheological properties and, in turn, their foaming behaviour. Foaming behaviour is a key parameter for cellular solids produced by mechanical foaming as it has a significant effect on the processing and properties of cellular materials. Foamability mainly impacts the density and the mechanical properties of the foams, while foam stability is crucial to achieving foams with low shrinkage and desirable pore morphology. This work aimed to investigate the influence of SDS on the foaming behaviour of concentrated gelatine foams by using a dynamic foam analyser. The study of maximum foam height created, foam formation behaviour, drainage behaviour, and foam structure with regard to bubble size and distribution were carried out in 10 wt% gelatine solutions prepared at different SDS/gelatine concentration ratios. Comparative rheological and viscometry measurements provided a good correlation with the data from the dynamic foam analyser measurements. SDS incorporation at optimum dosages and gelatine gelation led to highly stable foams at high expansion ratios. The viscosity increase of the hydrogel solution at SDS content increased was a key parameter for foam stabilization. In addition, the impact of SDS content on gelling time and gel strength also considerably impacted the foams' stability and pore structure.

Keywords: dynamic foam analyser, gelatine foams stability and foamability, gelatine-surfactant foams, gelatine-SDS rheology, gelatine-SDS viscosity

Procedia PDF Downloads 123

Authors: Lourenço Bastos, Filipa Carneiro, Bruno Vale, Rita Marques Joana Silva, Ricardo Freitas, Ângelo Marques, Sara Cortez, Alberta Coelho, Pedro Parreira, Liliana Sousa, Anabela Salgueiro, Bruno Silva

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The process of flushing is considered to be an adequate technique to reduce the risk of infection during the clinical practice of venous catheterization. Nonetheless, there is still a lack of adhesion to this method, in part due to the complexity of this procedure. The project SeringaDuo aimed to develop an innovative double-chamber syringe for intravenous sequential administration of drugs and serums. This device served the purpose of improving the adherence to the practice, through the reduction of manipulations needed, which also improves patient safety, and though the promotion of flushing practice by health professionals, by simplifying this task. To assist on the development of this innovative syringe, a numerical methodology was developed and validated in order to predict the syringe’s mechanical and flow behavior during the fluids’ loading and administration phases, as well as to allow the material behavior evaluation during its production. For this, three commercial numerical simulation software was used, namely ABAQUS, ANSYS/FLUENT, and MOLDFLOW. This methodology aimed to evaluate the concepts feasibility and to optimize the geometries of the syringe’s components, creating this way an iterative process for product development based on numerical simulations, validated by the production of prototypes. Through this methodology, it was possible to achieve a final design that fulfils all the characteristics and specifications defined. This iterative process based on numerical simulations is a powerful tool for product development that allows obtaining fast and accurate results without the strict need for prototypes. An iterative process can be implemented, consisting of consecutive constructions and evaluations of new concepts, to obtain an optimized solution, which fulfils all the predefined specifications and requirements.

Keywords: Venous catheterization, flushing, syringe, numerical simulation

Procedia PDF Downloads 135

Authors: Jasmin S. Nurkovic, Ljubisa Dj. Jovasevic, Zana C. Dolicanin, Zoran S. Bajin

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Ruptured muscles and tendons very often must be repatriated by open operation in young persons. In young, muscles are ruptured more often than tendons, at the sane time in older persons are more exposed to rupture than muscles. Ruptured of the calcaneus are the most present of all ruptures. Sometime the rupture is complete, but very often the incomplete rupture can be noticed. During six years, from 2006 to 2012, we treated nineteen male patients and three female patients with the rupture of tendon Achilles. The youngest patient was aged thirty two, and the oldest was also managed sixty four. The youngest female patient was forty one and the oldest was forty six. One of our patients who was under corticosteroid treatment did not take any part in sport activities but she was, as she told us, going for a long walk, the same was with other two patients one man and one woman. We had nineteen male patients age 32 to 64 and three female patients age 41, 44 and 46. Conservative treatment by cast was applied in five patients and very good results were in three of them. In two patients surgical treatment failed in patient’s age 53 and 64. Only one of all patients treated by surgery had healing problems because of necrotic changes of the skin where incision was made. One of our female patients age 45 was under steroid treatment for almost 20 years because of asthmatic problems. We suggested her wearing boots with 8cm long heels by day and by night eight weeks. The final results were satisfactory and all the time she was able to work and to walk. It was the only case we had with bilateral tendon rupture. After eight weeks the cast is removed and psychiatric treatment started, patient is using crutches with partial weight bearing over a period of two weeks. Quite the same treatment conservative treatment, only the cast is not removed after two but after four weeks. Everyday activities after the surgical treatment started ten weeks and sport activities can start after fourteen to sixteen weeks. An increased activity of our patient without previous preparing for forces activity can result, as we already see, with tendon rupture. Treatment is very long and very often surgical. We find that surgical treatment resulted as safer and better solution for patients. We also had a patient with spontaneous rupture of tendon during longer walking but this patient was under prolonged corticosteroid treatment.

Keywords: tendon, Achilles, rupture, sport

Procedia PDF Downloads 218

Authors: Rajkumar Ghosh

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India faces a critical task of water shortage, specifically during dry seasons, which adversely impacts agricultural productivity and food protection. Natural farming, specializing in sustainable practices, demands green water management in smart cities in India. This paper examines how rooftop rainwater harvesting (RRWH) can alleviate water scarcity and support sustainable organic farming practices in India. RRWH emerges as a promising way to increase water availability for the duration of dry intervals and decrease reliance on traditional water sources in smart cities. The look at explores the capacity of RRWH to enhance water use performance, help crop growth, enhance soil health, and promote ecological stability inside the farming ecosystem. The medical paper delves into the advantages, challenges, and implementation techniques of RRWH in organic farming. It addresses demanding situations, including seasonal variability of rainfall, limited rooftop vicinity, and monetary concerns. Moreover, it analyses broader environmental and socio-economic implications of RRWH for sustainable agriculture, emphasizing water conservation, biodiversity protection, and the social properly-being of farming communities. The belief underscores the importance of RRWH as a sustainable solution for reaching the aim of sustainable agriculture in natural farming in India. It emphasizes the want for further studies, policy advocacy, and capacity-building initiatives to promote RRWH adoption and assist the transformation in the direction of sustainable organic farming systems. The paper proposes adaptive strategies to triumph over demanding situations and optimize the advantages of RRWH in organic farming. By way of doing so, India can make vast development in addressing water scarcity issues and making sure a greater resilient and sustainable agricultural future in smart cities.

Keywords: rooftop rainwater harvesting, organic farming, green water management, food protection, ecological stabilty

Procedia PDF Downloads 64

Authors: Anh Nguyen, Jane Fisher, Thach Tran, Anh T. T. Tran

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Trait Emotional Intelligence is the knowledge, beliefs, and attitudes an individual has about their own and other people’s emotions. It is believed that trait emotional intelligence is a component of personality. Petrides’ Trait Emotional Intelligence Questionnaire (TEIQue) is well regarded and well-established, with validation data about its functioning among adults from many countries. However, there is little data yet about its use among Asian populations, including adolescents. The aims were to translate and culturally verify the Trait Emotional Intelligence Adolescent Short Form (TEIQue-ASF) and investigate content validity, construct validity, and reliability among adolescents attending high schools in Vietnam. Content of the TEIQue-ASF was translated (English to Vietnamese) and back-translated (Vietnamese to English) in consultation with bilingual and bicultural health researchers and pilot tested among 51 potential respondents. Phraseology and wording were then adjusted and the final version is named the VN-TEIQue-ASF. The VN-TEIQue-ASF’s properties were investigated in a cross-sectional elf-report survey among high school students in Central Vietnam. In total 1,546 / 1,573 (98.3%) eligible students from nine high schools in rural, urban, and coastline areas completed the survey. Explanatory Factor Analysis yielded a four-factor solution, including some with facets that loaded differently compared to the original version: Well-being, Emotion in Relationships, Emotion Self-management, and Emotion Sensitivity. The Cronbach’s alpha of the global score for the VN-TEIQue-ASF was .77. The VN-TEIQue-ASF is comprehensible and has good content and construct validity and reliability among adolescents in Vietnam. The factor structure is only partly replicated the original version. The VN-TEIQue-ASF is recommended for use in school or community surveys and professional study in education, psychology, and public health to investigate the trait emotional intelligence of adolescents in Vietnam.

Keywords: adolescents, construct validity, content validity, factor analysis, questionnaire validity, trait emotional intelligence, Vietnam

Procedia PDF Downloads 236

Authors: Maryam S. Ghoraishi, John E. Hawk, Thomas Thundat

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Understanding liquid properties in small scale has become important in recent decades as immerging new microelectromechanical systems (MEMS) devices have been widely used for micro pumps, drug delivery, and many other laboratory-on-microchips analysis. Often in microfluidic devices, fluids are transported electrokinetically. Therefore, extensive knowledge of fluid flow, heat transport, electrokinetics and electrochemistry are key to successful lab on a chip design. Among different microfluidic devices, recently developed hollow channel cantilever offers an ideal platform to study different fluid properties simultaneously without drastic decrease in quality factor which normally occurs when traditional cantilevers operate in the liquid phase. Using hollow channel cantilever, we monitor changes in density and viscosity of liquid while simultaneously investigating dielectric properties of alcohol water binary mixtures. Considerable research has been conducted on alcohol-water mixtures since such a mixture is a typical prototype for biomolecules, Micelle formation, and structural stability of proteins (to name a few). Here we show that hollow channel cantilever can be employed to investigate dielectric properties of ethanol/water mixtures in different concentrations. We study dynamic amplitude shifts of hollow channel cantilever oscillation at different concentrations of ethanol/water for different voltages. Our results show how interactions between solute and solvent, and possibly cluster formation, could change dielectric properties and dipole reorientation of the mixture, as well as the resulting force on the hollow cantilever. For comparison, we also examine higher conductivity ionic mixtures of sodium sulfate solution under the same conditions as low conductivity ethanol/water mixtures. We will show the results from systematic investigation of solvent effects on dielectric properties of the binary mixture. We will also address the question of resolution limits in dielectric study of analyte molecules imposed by solvent concentrations.

Keywords: dielectric constant, cantilever sensors, ethanol water mixtures, low frequency

Procedia PDF Downloads 175

Authors: Javeria Arain, Saad Malik

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The management of solid waste is a crucial and essential aspect of urban environmental management especially in a city with an ever increasing population such as Karachi. The total amount of municipal solid waste generated from Gulshan e Iqbal town on average is 444.48 tons per day and landfill sites are a widely accepted solution for final disposal of this waste. However, an improperly selected site can have immense environmental, economical and ecological impacts. To select an appropriate landfill site a number of factors should be kept into consideration to minimize the potential hazards of solid waste. The purpose of this research is to analyse the study area for the construction of an appropriate landfill site for disposal of municipal solid waste generated from Gulshan e-Iqbal Town by using geospatial techniques considering hydrological, geological, social and geomorphological factors. This was achieved using analytical hierarchy process and fuzzy analysis as a decision support tool with integration of geographic information sciences techniques. Eight most critical parameters, relevant to the study area, were selected. After generation of thematic layers for each parameter, overlay analysis was performed in ArcGIS 10.0 software. The results produced by both methods were then compared with each other and the final suitability map using AHP shows that 19% of the total area is Least Suitable, 6% is Suitable but avoided, 46% is Moderately Suitable, 26% is Suitable, 2% is Most Suitable and 1% is Restricted. In comparison the output map of fuzzy set theory is not in crisp logic rather it provides an output map with a range of 0-1, where 0 indicates least suitable and 1 indicates most suitable site. Considering the results it is deduced that the northern part of the city is appropriate for constructing the landfill site though a final decision for an optimal site could be made after field survey and considering economical and political factors.

Keywords: Analytical Hierarchy Process (AHP), fuzzy set theory, Geographic Information Sciences (GIS), Multi-Criteria Decision Analysis (MCDA)

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Authors: Yoftahe Nigussie

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This research explores the implementation of a vapor absorption refrigeration system (VARS) in mini-bus cars to enhance air conditioning efficiency. The conventional vapor compression refrigeration system (VCRS) in vehicles relies on mechanical work from the engine, leading to increased fuel consumption. The proposed VARS aims to utilize waste heat and exhaust gas from the internal combustion engine to cool the mini-bus cabin, thereby reducing fuel consumption and atmospheric pollution. The project involves two models: Model 1, a two-fluid vapor absorption system (VAS), and Model 2, a three-fluid VAS. Model 1 uses ammonia (NH₃) and water (H₂O) as refrigerants, where water absorbs ammonia rapidly, producing a cooling effect. The absorption cycle operates on the principle that absorbing ammonia in water decreases vapor pressure. The ammonia-water solution undergoes cycles of desorption, condensation, expansion, and absorption, facilitated by a generator, condenser, expansion valve, and absorber. The objectives of this research include reducing atmospheric pollution, minimizing air conditioning maintenance costs, lowering capital costs, enhancing fuel economy, and eliminating the need for a compressor. The comparison between vapor absorption and compression systems reveals advantages such as smoother operation, fewer moving parts, and the ability to work at lower evaporator pressures without affecting the Coefficient of Performance (COP). The proposed VARS demonstrates potential benefits for mini-bus air conditioning systems, providing a sustainable and energy-efficient alternative. By utilizing waste heat and exhaust gas, this system contributes to environmental preservation while addressing economic considerations for vehicle owners. Further research and development in this area could lead to the widespread adoption of vapor absorption technology in automotive air conditioning systems.

Keywords: room, zone, space, thermal resistance

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Authors: Tara Moore

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Madagascar is one of the regions of the world with the highest biodiversity, with more than 600 new species discovered in just the last decade. In parallel with its record-breaking biodiversity, Madagascar is also the tenth poorest country in the world. The resultant socio-economic pressures are leading to a highly threatened environment. In particular, deforestation is at the core of biodiversity and ecosystem loss, primarily from slash and burn agriculture and illegal rosewood tree harvesting. Effective policy response is imperative for improved conservation in Madagascar. However, these changes cannot come from the current, unstable government institutions. After a violent and politically turbulent coup in 2009, any effort to defend Madagascar's biodiversity has been eclipsed by the high corruption of government bodies. This paper presents three policy options designed for a private donor to invest in conservation in Madagascar. The first proposed policy consists of payments for ecosystem services model, which involves paying local Malagasy women to reforest nearby territories. The second option is a micro-irrigation system proposal involving relocating local Malagasy out of the threatened forest region. The final proposition is captive breeding funding for the Madagascar Fauna and Flora Group, which could then lead to new reintroductions in the threatened northeastern rainforests. In the end, all three options present feasible, impactful options for a conservation-minded major donor. Ideally, the policy change would involve a combination of all three options, as each provides necessary development and conservation re-structuring goals. Option one, payments for ecosystem services, would be the preferred choice if there were only enough funding for one project. The payments for ecosystem services project both support local populations and promotes sustainable development while reforesting the threatened Marojejy National Park. Regardless of the chosen policy solution, any support from a donor will make a huge impact if it supports both sustainable development and biodiversity conservation.

Keywords: captive breeding, cnservation policy, lemur conservation, Madagascar conservation, payments for ecosystem services

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Authors: Agoston Restas

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Introduction: This paper describes many initiatives and shows also practical examples which happened recently using Unmanned Aerial Systems (UAS) to support disaster management. Since the operation of manned aircraft at disasters is usually not only expensive but often impossible to use as well, in many cases managers fail to use the aerial activity. UAS can be an alternative moreover cost-effective solution for supporting disaster management. Methods: This article uses thematic division of UAS applications; it is based on two key elements, one of them is the time flow of managing disasters, other is its tactical requirements. Logically UAS can be used like pre-disaster activity, activity immediately after the occurrence of a disaster and the activity after the primary disaster elimination. Paper faces different disasters, like dangerous material releases, floods, earthquakes, forest fires and human-induced disasters. Research used function analysis, practical experiments, mathematical formulas, economic analysis and also expert estimation. Author gathered international examples and used own experiences in this field as well. Results and discussion: An earthquake is a rapid escalating disaster, where, many times, there is no other way for a rapid damage assessment than aerial reconnaissance. For special rescue teams, the UAS application can help much in a rapid location selection, where enough place remained to survive for victims. Floods are typical for a slow onset disaster. In contrast, managing floods is a very complex and difficult task. It requires continuous monitoring of dykes, flooded and threatened areas. UAS can help managers largely keeping an area under observation. Forest fires are disasters, where the tactical application of UAS is already well developed. It can be used for fire detection, intervention monitoring and also for post-fire monitoring. In case of nuclear accident or hazardous material leakage, UAS is also a very effective or can be the only one tool for supporting disaster management. Paper shows some efforts using UAS to avoid human-induced disasters in low-income countries as part of health cooperation.

Keywords: disaster management, floods, forest fires, Unmanned Aerial Systems

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Authors: Petra Borilova Linhartova, Michaela Ruckova, Sabina Sevcikova, Natalie Mlcuchova, Jan Bohm, Katerina Zukalova, Monika Vlachova, Jiri Dolina, Lumir Kunovsky, Radek Kroupa, Zdenek Pavlovsky, Zdenek Danek, Tereza Deissova, Lydie Izakovicova Holla, Ondrej Slaby, Zdenek Kala

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Esophageal adenocarcinoma (EAC) is a highly aggressive malignancy that frequently develops from Barrett's esophagus (BE), a premalignant pathologic change occurring in the lower end of the esophagus. Specific microRNAs (miRNAs), small non-coding RNAs that function as posttranscriptional regulators of gene expression, were repeatedly proved to play key roles in the pathogenesis of these diseases. This pilot study aimed to analyze four selected miRNAs in esophageal tissues from healthy controls (HC) and patients with reflux esophagitis (RE)/BE/EAC, as well as to compare expression at the site of Barrett's mucosa/adenocarcinoma and healthy esophageal tissue outside the area of the main pathology in patients with BE/EAC. In this pilot study, 22 individuals (3 HC, 8 RE, 5 BE, 6 EAC) were included and endoscopically examined. RNA was isolated from the fresh-frozen esophageal tissue (stored in the RNAlater™ Stabilization Solution −70°C) using the AllPrep DNA/RNA/miRNA Universal Kit. Subsequent RT-qPCR analysis was performed using selected TaqMan MicroRNA Assays for miR-21, miR-34a, miR-196a, miR-196b, and endogenous control (RNU44). While the expression of miR-21 in the esophageal tissue with the main pathology was decreased in BE and EAC patients in comparison to the group of HC and RE patients (p=0.01), the expression of miR-196a was increased in the BE and EAC patients (p<0.01). Correlations between those miRNAs expression in tissue and severity of diagnosis were observed (p<0.05). In addition, miR-196a was significantly more expressed at the site with the main pathology than in paired adjacent esophageal tissue in BE and EAC patients (p<0.01). In conclusion, our pilot results showed that miR-196a, which regulates the proliferation, invasion, and migration (and was previously associated with esophageal squamous cell carcinoma and marked as a potential therapeutic target), could be a diagnostic tissue biomarker for BE and EAC as well.

Keywords: microRNA, barrett´s esophagus, esophageal adenocarcinoma, biomarker

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Authors: C. Nathanailides, P. Logothetis, G. Kanlis S. Anastasiou, L. Kokokiris, P. Mpeza

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Farmed Red porgy (Pagrus pagrus) is one of the “new candidate fish species” for the diversification of Mediterranean aquaculture which is predomintly based on the cultivation of the European sea bass, (Dicenfrarchus labrax), and the gilthead sea bream, (Sparus aurata). The quality of farmed red porgy (Pagrus pagrus) was investigated with samples obtained from the local fish market in the region of Igoumenitsa, NW Greece. Sample of the fish (ungutted and with scales) were purchased from three local fish mongers and transported to the laboratory within few minutes in foamed polystyrene boxes in ice. The average weight of whole fish ranged between 271-289g. A sample of the fish flesh taken from the upper epaxial region was transferred aseptically to a stomacher bag containing sterile Buffered Peptone Water solution (0.1%) and homogenized. After serial dilutions in 0.1% peptone water, the homogenates were spread on the surface of agar plates. Total viable counts (TVC) were determined using plate count agar after incubation at 30 oC for 3 days. The quality attributes monitored during the present work included bacterial load (total mesophilic) and the pH of the flesh. There was a marginal increase in the price of fresh red porgy sold during the summer time, with prices ranging, over a period of four seasons, from 5.85 to 7.5 per kilo. The results of the microbiological analysis indicate that with the exception of summer samples (which exhibited 5.23 (±0.13) log cfu/g), the bacterial load remained well below the legal limits and was around 3.1 log cfu/g. The pH values varied between 6.54 and 6.69. The results indicate a possible influence of season on the bacterial load of fish sold in the market. Nevertheless, the parameters investigated in the present work indicate that the bacteria load was well below the legal limit and that fish were sold within few days after harvesting. The peak of bacterial load in the summer samples may be a result of a post-harvesting contamination of the farmed fish and temperature fluctuations during handling and transportation.

Keywords: fish quality, marketing, aquaculture, Pagrus pagrus

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Authors: Mayra Pilamunga, Edwin Vera

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The consumption of dark chocolate is beneficial due to its high content of flavonoids, catechins, and procyanidins. To improve its properties, fortification of chocolate with polyphenols, anthocyanins, soy milk powder and other compounds has been evaluated in several studies. However, to our best knowledge, the addition of carotenes to chocolate has not been tested. Carotenoids, especially ß-carotene and lutein, are widely distributed in fruits and vegetables so that they could be extracted from agro-industrial waste, such as fruit processing. On the other hand, limonene produces crystalline changes of cocoa butter and improves its consistency and viscosity. This study aimed to evaluate the production of dark chocolate with the addition of carotenes extracted from an agro industrial waste and to improve its rheological properties and crystallization, with orange essential oil. The dried and fermented cocoa beans were purchased in Puerto Quito, Ecuador, and had a fat content of 51%. Six types of chocolates were formulated, and two formulations were chosen, one at 65% cocoa and other at 70% cocoa, both with a solid: fat ratio of 1.4:1. With the formulations selected, the influence of the addition of 0.75% and 1.5% orange essential oil was evaluated, and analysis to measure the viscosity, crystallization and sensory analysis were done. It was found that essential oil does not generate significant changes in the properties of chocolate, but has an important effect on aroma and coloration, which changed from auburn to brown. The best scores on sensory analysis were obtained for the samples formulated with 0.75% essential oil. Prior to the formulation with carotenes, the extraction of these compounds from pineapple peels were performed. The process was done with and without a previous enzymatic treatment, with three solid-solvent ratios. The best treatment was using enzymes in a solids-solvent ratio of 1:12.5; the extract obtained under these conditions had 4.503 ± 0.214 μg Eq. β-carotene/mL. This extract was encapsulated with gum arabic and maltodextrin, and the solution was dried using a freeze dryer. The encapsulated carotenes were added to the chocolate in an amount of 1.7% however 60,8 % of them were lost in the final product.

Keywords: cocoa, fat crystallization, limonene, carotenoids, pineapple peels

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Authors: Sara S. Fouad, Omneya Messallam

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In 1818, a seventy-five kilometer long canal was dug (called the Mahmoudiyah canal) connecting between Alexandria city in Egypt and the western branch of the Nile. It was a productive resource and vital to its environment, context, transportation, and recreation. It played a significant role in people’s lives and Alexandria city’s shape. The canal, which was the main vein of goods’ transporting from Alexandria’s seaport to the different parts of Egypt, was still in use today as a major source of clear water in the city. But nowadays, Mahmoudiyah canal is converting into ‘dead waterway’. The canal became sources of pollution as a result of solid and industrial waste thus causing many diseases, destroying communities and biodiversity, with urban invasion, the loss of community aesthetic value and healthy environment. Therefore, this paper aims to propose an urban strategy, as a solution to revive the forgotten canal, through recreating a cultural promenade on its shore. The main aim of this research is to formulate decent quality of life, unpolluted space, an area gathering the city space for nature, tourism and investments. As a case study, this paper investigates Mahmoudiyah canal through urban and ecological analyses, aiming to design an urban strategy for reviving it by creating a cultural promenade enriched with public spaces and green areas, which can most probably enhance the quality of life, city re-living and development. Community participation is also considered as vital and intrinsic implementation stage. The empirical research involved using several data assembly methods such as interviews, mental mapping, structural observations and questionnaires. The paper ends with a set of conclusions leading to proposals for the Mahmoudiyah canal revitalization considering the complex challenges and processes of sustainable regeneration focusing on city’s rehabilitation and lost identity.

Keywords: Mahmoudiyah canal, community aesthetic value, city re-living, cultural promenade

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Authors: Farheen Tabassum, Shoab Ahmed Khan

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The brutality of attacks on networks and decisive infrastructures are on the climb over recent years and appears to continue to do so. Distributed Denial of service attack is the most prevalent and easy attack on the availability of a service due to the easy availability of large botnet computers at cheap price and the general lack of protection against these attacks. Application layer DDoS attack is DDoS attack that is targeted on wed server, application server or database server. These types of attacks are much more sophisticated and challenging as they get around most conventional network security devices because attack traffic often impersonate normal traffic and cannot be recognized by network layer anomalies. Conventional techniques of single-hosted security systems are becoming gradually less effective in the face of such complicated and synchronized multi-front attacks. In order to protect from such attacks and intrusion, corporation among all network devices is essential. To overcome this issue, a collaborative intrusion detection system (CIDS) is proposed in which multiple network devices share valuable information to identify attacks, as a single device might not be capable to sense any malevolent action on its own. So it helps us to take decision after analyzing the information collected from different sources. This novel attack detection technique helps to detect seemingly benign packets that target the availability of the critical infrastructure, and the proposed solution methodology shall enable the incident response teams to detect and react to DDoS attacks at the earliest stage to ensure that the uptime of the service remain unaffected. Experimental evaluation shows that the proposed collaborative detection approach is much more effective and efficient than the previous approaches.

Keywords: Distributed Denial-of-Service (DDoS), Collaborative Intrusion Detection System (CIDS), Slowloris, OSSIM (Open Source Security Information Management tool), OSSEC HIDS

Procedia PDF Downloads 335

Authors: Florina Dutt, Subhajit Das, Matthew Swartz

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Lighting design and its impact on indoor comfort conditions are an integral part of good interior design. Impact of lighting in an interior space is manifold and it involves many sub components like glare, color, tone, luminance, control, energy efficiency, flexibility etc. While other components have been researched and discussed multiple times, this paper discusses the research done to understand the glare component from an artificial lighting source in an indoor space. Consequently, the paper discusses a parametric model to convey real time glare level in an interior space to the designer/ architect. Our end users are architects and likewise for them it is of utmost importance to know what impression the proposed lighting arrangement and proposed furniture layout will have on indoor comfort quality. This involves specially those furniture elements (or surfaces) which strongly reflect light around the space. Essentially, the designer needs to know the ramification of the ‘discomfortable glare’ at the early stage of design cycle, when he still can afford to make changes to his proposed design and consider different routes of solution for his client. Unfortunately, most of the lighting analysis tools that are present, offer rigorous computation and analysis on the back end eventually making it challenging for the designer to analyze and know the glare from interior light quickly. Moreover, many of them do not focus on glare aspect of the artificial light. That is why, in this paper, we explain a novel approach to approximate interior glare data. Adding to that we visualize this data in a color coded format, expressing the implications of their proposed interior design layout. We focus on making this analysis process very fluid and fast computationally, enabling complete user interaction with the capability to vary different ranges of user inputs adding more degrees of freedom for the user. We test our proposed parametric model on a case study, a Computer Lab space in our college facility.

Keywords: computational geometry, glare impact in interior space, info visualization, parametric lighting analysis

Procedia PDF Downloads 322

Authors: Waddah Abdullah, Saleh Al-Sarem

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Electrokinetic remediation was undoubtedly proven to be one of the most efficient techniques used to clean up soils contaminated with polar charged contaminants (such as heavy metals) and non-polar organic contaminants. It can be efficiently used to clean up low permeability mud, wastewater, electroplating wastes, sludge, and marine dredging. This study presented and discussed the results of electrokinetic remediation processes to clean up soils contaminated with nickel. Two types of electrokinetics cells were used: an open cell and an advanced cylindrical cell. Two types of soils were used for this investigation; the Azraq green clay which has very low permeability taken from the eastern part of Jordan (city of Azraq) and a sandy soil having, relatively, very high permeability. The clayey soil was spiked with 500 ppm of nickel, and the sandy soil was spiked with 1500 ppm of nickel. Fully saturated and partially saturated clayey soils were used for the clean-up process. Clayey soils were tested under a direct current of 80 mA and 50 mA to study the effect of the electrical current on the remediation process. Chelating agent (Na-EDTA), disodium ethylene diamine tetraacetatic acid, was used in both types of soils to enhance the electroremediation process. The effect of carbonates presence in the contaminated soils, also, was investigated by use of sodium carbonate and calcium carbonate. pH changes in the anode and the cathode compartments were controlled by use of buffer solutions. The results of the investigation showed that for the fully saturated clayey soil spiked with nickel had an average removal efficiency of 64%, and the average removal efficiency was 46% for the unsaturated clayey soil. For the sandy soil, the average removal efficiency of Nickel was 90%. Test results showed that presence of carbonates in the remediated soils retarded the clean-up process of nickel-contaminated soils (removal efficiency was reduced from 90% to 60%). EDTA enhanced decontamination of nickel contaminated clayey and sandy soils with carbonates was studied. The average removal efficiency increased from 60% (prior to using EDTA) to more than 90% after using EDTA.

Keywords: buffer solution, EDTA, electroremediation, nickel removal efficiency

Procedia PDF Downloads 159

Authors: Nahid Hassanshahi, Ayoub Karimi-Jashni, Nasser Talebbeydokhti

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Due to the economic and environmental benefits of producing less waste, the US Environmental Protection Agency (EPA) introduces source reduction as one of the most important means to deal with the problems caused by increased landfills and pollution. Waste reduction involves all waste management methods, including source reduction, recycling, and composting, which reduce waste flow to landfills or other disposal facilities. Source reduction of waste can be studied from two perspectives: avoiding waste production, or reducing per capita waste production, and waste deviation that indicates the reduction of waste transfer to landfills. The present paper has investigated home composting as a managerial solution for reduction of waste transfer to landfills. Home composting has many benefits. The use of household waste for the production of compost will result in a much smaller amount of waste being sent to landfills, which in turn will reduce the costs of waste collection, transportation and burial. Reducing the volume of waste for disposal and using them for the production of compost and plant fertilizer might help to recycle the material in a shorter time and to use them effectively in order to preserve the environment and reduce contamination. Producing compost in a home-based manner requires very small piece of land for preparation and recycling compared with other methods. The final product of home-made compost is valuable and helps to grow crops and garden plants. It is also used for modifying the soil structure and maintaining its moisture. The food that is transferred to landfills will spoil and produce leachate after a while. It will also release methane and greenhouse gases. But, composting these materials at home is the best way to manage degradable materials, use them efficiently and reduce environmental pollution. Studies have shown that the benefits of the sale of produced compost and the reduced costs of collecting, transporting, and burying waste can well be responsive to the costs of purchasing home compost machine and the cost of related trainings. Moreover, the process of producing home compost may be profitable within 4 to 5 years and as a result, it will have a major role in reducing waste management.

Keywords: compost, home compost, reducing waste, waste management

Procedia PDF Downloads 395

Authors: Maha Bakakri, Rachid Tadili, Fatiha Lemmini

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Morocco is one of the few countries that have kept their traditional crafts, despite the competition of modern industry and its impact on manual labor. Therefore the optimization of energy consumption becomes an obligation and this is the purpose of this document. In this work we present some characteristics of the furnace studied, its operating principle and the experimental measurements of the evolutions of the temperatures inside and outside the walls of the furnace, values which will be used later in the calculation of its thermal losses. In order to determine the major source of the thermal losses of the furnace we have established the heat balance of the furnace. The energy consumed, the useful energy and the thermal losses through the walls and the chimney of the furnace are calculated thanks to the experimental measurements which we realized for several firings. The results show that the energy consumption of this type of furnace is very high and that the main source of energy loss is mainly due to the heat losses of the combustion gases that escape from the furnace by the chimney while the losses through the walls are relatively small. it have opted for energy recovery as a solution where we can recover some of the heat lost through the use of a heat exchanger system using a double tube introduced into the flue gas exhaust stack compartment. The study on the heat recovery system is presented and the heat balance inside the exchanger is established. In this paper we also present the numerical modeling of heat transfer by conduction through the walls of the furnace. A numerical model has been established based on the finite volume method and the double scan method. It makes it possible to determine the temperature profile of the furnace and thus to calculate the thermal losses of its walls and to deduce the thermal losses due to the combustion gases. Validation of the model is done using the experimental measurements carried out on the furnace. The results obtained in this work, relating to the energy consumed during the operation of the furnace are important and are part of the energy efficiency framework that has become a key element in global energy policies. It is the fastest and cheapest way to solve energy, environmental and economic security problems.

Keywords: energy cunsumption, energy recovery, modeling, energy eficiency

Procedia PDF Downloads 41

Authors: Sarah Nasser, Anne Moreau, Alain Hedoux, Romain Jeantet, Guillaume Delaplace

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Background: Spray dryed powders containing some caseins are commonly produced in dairy industry. It is widely admitted that the structure of casein evolves during powder storage, inducing a loss of solubility. However few studies evaluate accurately the destabilization mechanisms at molecular and mesoscopic level, in particular for Native Phospho Casein powder (NPC). Consequently, at the state of the art, it is very difficult to assess which secondary structure change or crosslinks initiate insolubility during storage. To address this issue, controlled ageing conditions have been applied to a NPC powder (which was obtained by spray drying a concentrate containing a higher content of casein (90%), whey protein (8%) and lactose (few %)). Evolution of structure and loss of solubility, with the effects of temperature and time of storage were systematically reported. Methods: FTIR spectroscopy, Raman and Circular Dichroism were used to monitor changes of secondary structure in dry powder and in solution after rehydration. Besides, proteomic tools and electrophoresis have been performed after varying storage conditions for evaluating aggregation and post translational modifications, like lactosylation or phosphorylation. Finally, Tof Sims and MEB were used to follow in parallel evolution of structure in surface and skin formation due to storage. Results + conclusion: These results highlight the important role of storage temperature in the stability of NPC. It is shown that this is not lactosylation at the heart of formation of aggregates, as advanced in others publications This is almost the rise of multitude post translational modifications (chemical cross link), added to disulphide bridges (physical cross link) wich contribute to the destabilisation of structure and aggregation of casein. A relative quantification of each kind of cross link, source of aggregates, is proposed. In addition, it has been proved that migration of lipids and formation of skin in surface during the ageing also explains the evolution of structure casein and thus the alterations of functional properties of NPC powder.

Keywords: casein, cross link, powder, storage

Procedia PDF Downloads 357

Authors: Kinga Mylkie, Pawel Nowak, Marta Z. Borowska

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The most important proteins in human serum responsible for drug binding are human serum albumin (HSA) and α1-acid glycoprotein (AGP). The AGP molecule is a glycoconjugate containing a single polypeptide chain composed of 183 amino acids (the core of the protein), and five glycan branched chains (sugar part) covalently linked by an N-glycosidic bond with aspartyl residues (Asp(N) -15, -38, -54, -75, - 85) of polypeptide chain. This protein plays an important role in binding alkaline drugs, a large group of drugs used in psychiatry, some acid drugs (e.g., coumarin anticoagulants), and neutral drugs (steroid hormones). The main goal of the research was to obtain magnetic nanoparticles coated with biopolymers in a chemically modified form, which will have highly reactive functional groups able to effectively immobilize the glycoprotein (acid α1-glycoprotein) without losing the ability to bind active substances. The first phase of the project involved the chemical modification of biopolymer starch. Modification of starch was carried out by methods of organic synthesis, leading to the preparation of a polymer enriched on its surface with aldehyde groups, which in the next step was coupled with 3-aminophenylboronic acid. Magnetite nanoparticles coated with starch were prepared by in situ co-precipitation and then oxidized with a 1 M sodium periodate solution to form a dialdehyde starch coating. Afterward, the reaction between the magnetite nanoparticles coated with dialdehyde starch and 3-aminophenylboronic acid was carried out. The obtained materials consist of a magnetite core surrounded by a layer of modified polymer, which contains on its surface dihydroxyboryl groups of boronic acids which are capable of binding glycoproteins. Magnetic nanoparticles obtained as carriers for plasma protein immobilization were fully characterized by ATR-FTIR, TEM, SEM, and DLS. The glycoprotein was immobilized on the obtained nanoparticles. The amount of mobilized protein was determined by the Bradford method.

Keywords: glycoproteins, immobilization, magnetic nanoparticles, polysaccharides

Procedia PDF Downloads 90

Authors: B. Dehghan, T. Toppi, M. Aprile, M. Motta

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The environmental concerns related to global warming and ozone layer depletion along with the growing worldwide demand for heating and cooling have brought an increasing attention toward ecological and efficient Heating, Ventilation, and Air Conditioning (HVAC) systems. Furthermore, since space heating accounts for a considerable part of the European primary/final energy use, it has been identified as one of the sectors with the most challenging targets in energy use reduction. Heat pumps are commonly considered as a technology able to contribute to the achievement of the targets. Current research focuses on the full load operation and seasonal performance assessment of three gas-driven absorption heat pump cycles. To do this, investigations of the gas-driven air-source ammonia-water absorption heat pump systems for small-scale space heating applications are presented. For each of the presented cycles, both full-load under various temperature conditions and seasonal performances are predicted by means of numerical simulations. It has been considered that small capacity appliances are usually equipped with fixed geometry restrictors, meaning that the solution mass flow rate is driven by the pressure difference across the associated restrictor valve. Results show that gas utilization efficiency (GUE) of the cycles varies between 1.2 and 1.7 for both full and partial loads and vapor exchange (VX) cycle is found to achieve the highest efficiency. It is noticed that, for typical space heating applications, heat pumps operate over a wide range of capacities and thermal lifts. Thus, partially, the novelty introduced in the paper is the investigation based on a seasonal performance approach, following the method prescribed in a recent European standard (EN 12309). The overall result is a modest variation in the seasonal performance for analyzed cycles, from 1.427 (single-effect) to 1.493 (vapor-exchange).

Keywords: absorption cycles, gas utilization efficiency, heat pump, seasonal performance, vapor exchange cycle

Procedia PDF Downloads 85

Authors: Adha Bayu Wijaya, A. Zainal Abidin, Naufal Baihaqi, Joko Suprayitno, Astika Titistiti, Muslim Adi Wijaya, Endah Tri Lestari, Agung Wibowo

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Sulfur is a non-metallic chemical element in the form of a yellow crystalline solid with the chemical formula, and is formed from several types of natural and artificial chemical reactions. Commercial applications of sulfur processed products can be found in various aspects of life, for example in the use of processed sulfur as paving blocks. The Gundih Central Processing Plant (CPP) is capable of producing 14 tons/day of sulfur pellets. This amount comes from the high H2S content of the wells with a total concentration of 20,000 ppm and a volume accumulation of 14 MMSCFD acid gas. H2S is converted to sulfur using the thiobacillus microbe in the Biological Sulfur Recovery Unit (BSRU) with a sulfur product purity level greater than 95%. In 2018 sulfur production at Gundih CPP was recorded at 4044 tons which could potentially trigger serious problems from an environmental aspect. The use of sulfur as material for making paving blocks is an alternative solution in addressing the potential impact on the environment, as regulated by Government Regulation No.22 of Year 2021 concerning the Waste Management of Non-Hazardous and Toxic Substances (B3), and the high cost of handling sulfur by third parties. The design mix of ratio sulfur paving blocks is 22% cements, rock ash 67%, and 11% of sulfur pellets. The sulfur used in making the paving mixture is pure sulfur, namely the side product category without any contaminants, thereby eliminating the potential for environmental pollution when implementing sulfur paving. Strength tests of sulfur paving materials have also been confirmed by external laboratories. The standard used in making sulfur paving blocks refers to the SNI 03-0691-1996 standard. With the results of sulfur paving blocks made according to quality B. Currently, sulfur paving blocks are used in building access to wells locations and in public roads in the Cepu Field area as a contribution from Corporate Social Responsibility (CSR).

Keywords: sulphur, innovation, paving block, CSR, sulphur paving

Procedia PDF Downloads 35