Search results for: water potential
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 18031

Search results for: water potential

3841 Contractual Risk Transfer in Islamic Home Financing: Analysis in Bank Malaysia

Authors: Ahmad Dahlan Salleh, Nik Abdul Rahim Nik Abdul Ghani, Muhamad Firdaus M. Hatta

Abstract:

Risk management has implications on pricing, governance arrangements, business practices and strategy. Nowadays, home financing contract offers more in the risk transfer form to increase bank profit. This is parallel with Islamic jurisprudence method al-Kharaj bi al-thaman (gain accompanies liability for loss) and al-ghurm bil ghunm (gain is justified with risk) that determine the matching between risk transfer and returns. Malaysian financing trend is to buy house. Besides, exists transparency lacking risk transfer issues to the clients because of not been informed clearly. Terms and conditions of each financing also do not reflect clearly that the risk has been transferred to the client, justifying a determination price been made. The assumption on risk occurrence is also inaccurate as each risk is different with the type of financing contract. This makes the Islamic Financial Services Act 2013 in providing standards that transparent and consistent can be used by Islamic financial institution less effective. This study examines how far the level of the risk and obligation incurred by bank and client under various Islamic home financing contract. This research is qualitative by using two methods, document analysis, and semi-structured interviews. Document analysis from literature review to identify profile, themes and risk transfer element in home financing from Islamic jurisprudence perspective. This study finds that need to create a risk transfer parameter by banks which are consistent with risk transfer theory according to Islamic jurisprudence. This study has potential to assist the authority in Islamic finance such as The Central Bank of Malaysia (Bank Negara Malaysia) in regulating Islamic banking industry so that the risk transfer valuation in home financing contract based on home financing good practice and determined risk limits.

Keywords: risk transfer, home financing contract, Sharia compliant, Malaysia

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3840 Electric Field-Induced Deformation of Particle-Laden Drops and Structuring of Surface Particles

Authors: Alexander Mikkelsen, Khobaib Khobaib, Zbigniew Rozynek

Abstract:

Drops covered by particles have found important uses in various fields, ranging from stabilization of emulsions to production of new advanced materials. Particles at drop interfaces can be interlocked to form solid capsules with properties tailored for a myriad of applications. Despite the huge potential of particle-laden drops and capsules, the knowledge of their deformation and stability are limited. In this regard, we contribute with experimental studies on the deformation and manipulation of silicone oil drops covered with micrometer-sized particles subjected to electric fields. A mixture of silicone oil and particles were immersed in castor oil using a mechanical pipette, forming millimeter sized drops. The particles moved and adsorbed at the drop interfaces by sedimentation, and were structured at the interface by electric field-induced electrohydrodynamic flows. When applying a direct current electric field, free charges accumulated at the drop interfaces, yielding electric stress that deformed the drops. In our experiments, we investigated how particle properties affected drop deformation, break-up, and particle structuring. We found that by increasing the size of weakly-conductive clay particles, the drop shape can go from compressed to stretched out in the direction of the electric field. Increasing the particle size and electrical properties were also found to weaken electrohydrodynamic flows, induce break-up of drops at weaker electric field strengths and structure particles in chains. These particle parameters determine the dipolar force between the interfacial particles, which can yield particle chaining. We conclude that the balance between particle chaining and electrohydrodynamic flows governs the observed drop mechanics.

Keywords: drop deformation, electric field induced stress, electrohydrodynamic flows, particle structuring at drop interfaces

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3839 A Surrealist Play of Associations: Neoliberalism, Critical Pedagogy and Surrealism in Secondary English Language Arts

Authors: Stephanie Ho

Abstract:

This project utilizes principles derived from the Surrealist movement to prioritize creative and critical thinking in secondary English Language Arts (ELA). The implementation of Surrealist-style pedagogies within an ELA classroom will be rooted in critical, radical pedagogy, which addresses the injustices caused by economic-oriented educational systems. The use of critical pedagogy will enable the subversive artistic and political aims of Surrealism to be transmitted to a classroom context. Through aesthetic reading strategies, appreciative questioning and dialogue, students will actively critique the power dynamics which structure (and often restrict) their lives. Within the ELA domain, cost-effective approaches often replace the actual “arts” of ELA. This research will therefore explore how Surrealist-oriented pedagogies could restore imaginative freedom and deconstruct conceptual barriers (normative standards, curricular constraints, and status quo power relations) in secondary ELA. This research will also examine how Surrealism can be used as a political and pedagogical model to treat societal problems mirrored in ELA classrooms. The stakeholders are teachers, as they experience constant pressure within their practices. Similarly, students encounter rigorous, results-based pressures. These dynamics contribute to feelings of powerlessness, thus reinforcing a formulaic model of ELA. The ELA curriculum has potential to create laboratories for critical discussion and active movement towards social change. This proposed research strategy of Surrealist-oriented pedagogies could enable students to experiment with social issues and develop senses of agency and voice that reflect awareness of contemporary society while simultaneously building their ELA skills.

Keywords: arts-informed pedagogies, language arts, literature, surrealism

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3838 Feeling, Thinking, Acting: The Role of Subjective Social Class and Social Class Identity on Emotions, Attitudes and Prosocial Behavior Towards Muslim Immigrants in Belgium

Authors: Theresa Zagers, Rita Guerra

Abstract:

Most research investigating how receiving communities perceive, and experience migration has overlooked the potential role of subjective social class and social class identity in positive intergroup relations and social cohesion of migrants and host societies. The present study aimed to provide insights to understand this relationship and focused on three important features: prosocial behaviour, attitudes and emotions towards Muslim immigrants in Flanders, Belgium. Building on relative deprivation-gratification theory we examined the indirect relationships of subjective social class on prosocial behaviour/intentions, attitudes and emotions via relative deprivation (RD), as well as the moderator role of the importance of social class identity. 431 Belgian participants participated in an online survey study. Overall, our results supported the predicted indirect effect of subjective social class: the lower the subjective social class, the higher the perceptions of relative deprivation, which in turn is related to less prosocial behaviour intentions, and more negative attitudes and emotions towards immigrants. This indirect effect was, however, not moderated by the importance of social class identity. Interestingly, the direct effects of subjective social class showed a different pattern: when bypassing deprivation our results showed higher subjective social class was detrimental for intergroup relations (more negative attitudes and emotions), and that lower subjective social class was positively related to prosocial intentions for those identifying highly with their class identity. Overall, we gained valuable insights in the relationship of subjective social class and the three features of intergroup relations.

Keywords: social class, relative deprivation-gratification, prosocial behavior, attitudes, emotions, Muslim immigrants

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3837 Protective Coating Layers via Phosphazene Compounds for Stabilizing Silicon Anode Materials

Authors: Adjmal Ghaur, Christoph Peschel, Iris Dienwiebel, Lukas Haneke, Leilei Du , Laurin Profanter, Tobias Placke, Martin Winter

Abstract:

In recent years, lithium-ion batteries (LIBs)are widely used in electric vehicles (EVs) and mobile energy storage devices (ESDs), which has led to higher requirements for energy density. To fulfill these requirements, tremendous attention has been paid to design advanced LIBs with various siliconactive materials as alternative negative electrodes to replace graphite (372 mAh g⁻¹)due to their high theoretical gravimetric capacity (4200mAh g⁻¹). However, silicon as potential anode material suffers from huge volume changes during charging and discharging and has poor electronicconductivity which negatively impacts the long-term performance and preventshigh silicon contents from practical application. Additionally, an unstable crystalline silicon structure tends to pulverization during the (de)lithiation process. To compensate for the volume changes, alleviate pulverization, and maintain high electronicconductivity, silicon-doped graphite composites with protecting coating layers are a promising approach. In this context, phosphazene compounds are investigated concerning their silicon protecting properties in silicon-doped graphite composites. In detail, electrochemical performance measurements in pouch full-cells(NCM523||SiOx/C), supressing gas formation properties, and post-mortem analyzes were carried out to characterize phosphazene compounds as additive materials. The introduction of the dual-additive approach in state-of-the-art electrolytes leads to synergistic effects between FEC and phosphazene compounds which accelerate the durability of silicon particles and results in enhanced electrochemical performance.

Keywords: silicon, phosphazene, solid electrolyte interphase, electrolyte, gasmeasurements

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3836 Stronger Together – Micro-Entrepreneurs’ Resilience Development in a Communal Training Space 

Authors: Halonen

Abstract:

Covid-19 pandemic and the succeeding crises have profoundly shaken the accustomed ways of interaction and thereby challenged the customary engagement patterns among entrepreneurs Consequently, this has led to the experience of lack of collegial interaction for some. Networks and relationships are a crucial factor to strengthening resilience, being especially significant in non-ordinary times. This study aims to shed light on entrepreneurs’ resilience development in and through entrepreneurs’ communal and training space. The context for research is a communal training space in a municipality in Finland of which goal is to help entrepreneurs to experience of peer support and community as part of the "tribe" is strengthened, the entrepreneurs' well-being at work, resilience, ability to change, innovativeness and general life management is strengthened. This communal space is regarded as an example of a physical community of practice (CoP) of entrepreneurs. The research aims to highlight the importance of rediscovering the “new normal” communality as itself but as a key building block of resilience. The initial research questions of the study are: RQ1: What is the role of entrepreneurs’ CoP and communal space in nurturing resilience development among them? RQ2: What positive entrepreneurial outcomes can be achieved through established CoP. The data will be gathered starting from the launch of the communality space in September 2023 onwards. It includes participatory observations of training gatherings, interviews with entrepreneurs and utilizes action research as the method. The author has an active role in participating and facilitating the development. The full paper will be finalized by the fall 2024. The idea of the new normal communality in a CoP among entrepreneurs is to be rediscovered due to its positive impact on entrepreneur’s resilience and business success. The other implications of study can extend to wider entrepreneurial ecosystem and other key stakeholders. Especially emphasizing the potential of communality in CoP for fostering entrepreneurs’ resilience and well-being ensuing business growth, community-driven entrepreneurship development and vitality of the case municipality.

Keywords: resilience, resilience development, communal space, community of practice (CoP)

Procedia PDF Downloads 63
3835 'Get the DNR': Exploring the Impact of an Educational eModule on Internal Medicine Residents' Attitudes and Approaches to Goals of Care Conversations

Authors: Leora Branfield Day, Stephanie Saunders, Leah Steinberg, Shiphra Ginsburg, Christine Soong

Abstract:

Introduction: Discordance between patients expressed and documented preferences at the end of life is common. Although junior trainees frequently lead goals of care (GOC) conversations, lack of training can result in poor communication. Based on a needs assessment, we developed an interactive electronic learning module (eModule) for conducting patient-centred GOC discussions. The purpose of this study was to evaluate the impact of the eModule on residents’ attitudes towards GOC conversations. Methods: First-year internal medicine residents (n=11) from the University of Toronto selected using purposive sampling underwent semi-structured interviews before and after completing a GOC eModule. Interviews were anonymized, transcribed and open-coded using NVivo. Using a constructivist grounded theory approach, we developed a framework to understand the attitudes of residents to GOC conversations before and after viewing the module. Results: Before the module, participants described limited training and negative emotions towards GOC conversations. Many focused on code status and procedure choices (e.g., ventilation) instead of eliciting patient-centered values. Pressure to “get the DNR" led to conflicting feelings and distress. After the module, participants’ approached conversations with a greater focus on patient values and process. They felt more prepared and comfortable, recognizing the complexity of conversations and the importance of patient-centeredness. Conclusions: A novel GOC eModule allowed residents to develop a patient-centered and standardized approach to GOC conversations while improving confidence and preparedness. This resource could be an effective strategy toward attaining a critical communication competency among learners with the potential to enhance accurate GOC documentation.

Keywords: goals of care conversations, communication skills, emodule, medical education

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3834 The Effect of Undernutrition on Sputum Culture Conversion and Treatment Outcomes among People with Multidrug-Resistant Tuberculosis: A Systematic Review and Meta-Analysis

Authors: Fasil Wagnew, Kerri Viney, Kefyalew Addis Alene, Matthew Kelly, Darren Gray

Abstract:

Background: Undernutrition is a risk factor for tuberculosis (TB), including poor treatment outcomes. However, evidence regarding the effect of undernutrition on TB treatment outcomes is not well understood. We aimed to evaluate the effect of undernutrition on sputum culture conversion and treatment outcomes among people with multi-drug resistance (MDR)-TB. Methods: We searched for publications in the Medline, Embase, Scopus, and Web of Science databases without restrictions on geography or year of publication. We conducted a random-effect meta-analysis to estimate the effects of undernutrition on sputum culture conversion and treatment outcomes. Two reviewers independently assessed the study eligibility, extracted the necessary information, and assessed the risk of bias. Depending on the nature of the data, odds ratio (OR) and hazard ratio (HR) with 95% confidence intervals (CIs) were used to summarize the effect estimates. Potential publication bias was checked using funnel plots and Egger’s tests. Results: Of 2358 records screened, 59 studies comprising a total of 31,254 people with MDR-TB were included. Undernutrition was significantly associated with a lower sputum culture conversion rate (HR 0·7, 95% CI 0·6–0·9, I2=67·1%) and a higher rate of mortality (OR 2·9, 95%CI 2·1–3·8, I2=23·7%) and unfavourable treatment outcomes (OR 1·8, 95%CI 1·5–2·0, I2=72·7%). There was no statistically significant publication bias in the included studies. Three studies were low, forty-two studies were moderate, and fourteen studies were high quality. Interpretations: Undernutrition was significantly associated with unfavourable treatment outcomes, including mortality and lower sputum culture conversion among people with MDR-TB. These findings have implications for supporting targeted nutritional interventions alongside standardised second-line TB drugs.

Keywords: undernutrition, MDR-TB, sputum culture conversion, treatment outcomes, meta-analysis

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3833 Ozone Therapy and Pulsed Electromagnetic Fields Interplay in Controlling Tumor Growth, Symptom and Pain Management: A Case Report

Authors: J. F. Pollo Gaspary, F. Peron Gaspary, E. M. Simão, R. Concatto Beltrame, G. Orengo de Oliveira, M. S. Ristow Ferreira, F. Sartori Thies, I. F. Minello, F. dos Santos de Oliveira

Abstract:

Background: The immune system has evolved several mechanisms to protect the host against cancer, and it has now been suggested that the expansion of its functions may prevent tumor growth and control the symptoms of cancer patients. Two techniques, ozone therapy and pulsed electromagnetic fields (PEMF), are independently associated with an increase in the immune system functions and they maybe help palliative care of patients in these conditions. Case Report: A patient with rectal adenocarcinoma with metastases decides to interrupt the clinical chemotherapy protocol due to refractoriness and side effects. As a palliative care alternative treatment it is suggested to the patient the use of ozone therapy associated with PEMF techniques. Results: The patient reports an improvement in well-being, in autonomy and in pain control. Imaging tests confirm a pause in tumor growth despite more than 60 days without using classic treatment. These results associated with palliative care alternative treatment stimulate the return to the chemotherapy protocol. Discussion: This case illustrates that these two techniques can contribute to the control of tumor growth and refractory symptoms, such as pain, probably by enhancing the immune system. Conclusions: The potential use of the combination of these two therapies, ozone therapy and PEMF therapy, can contribute to palliation of cancer patients, alone or in combination with pharmacological therapies. The conduct of future investigations on this paradigm can elucidate how much these techniques contribute to the survival and well-being of these patients.

Keywords: cancer, complementary and alternative medicine , ozone therapy, palliative care, PEMF therapy

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3832 A Study on the Different Components of a Typical Back-Scattered Chipless RFID Tag Reflection

Authors: Fatemeh Babaeian, Nemai Chandra Karmakar

Abstract:

Chipless RFID system is a wireless system for tracking and identification which use passive tags for encoding data. The advantage of using chipless RFID tag is having a planar tag which is printable on different low-cost materials like paper and plastic. The printed tag can be attached to different items in the labelling level. Since the price of chipless RFID tag can be as low as a fraction of a cent, this technology has the potential to compete with the conventional optical barcode labels. However, due to the passive structure of the tag, data processing of the reflection signal is a crucial challenge. The captured reflected signal from a tag attached to an item consists of different components which are the reflection from the reader antenna, the reflection from the item, the tag structural mode RCS component and the antenna mode RCS of the tag. All these components are summed up in both time and frequency domains. The effect of reflection from the item and the structural mode RCS component can distort/saturate the frequency domain signal and cause difficulties in extracting the desired component which is the antenna mode RCS. Therefore, it is required to study the reflection of the tag in both time and frequency domains to have a better understanding of the nature of the captured chipless RFID signal. The other benefits of this study can be to find an optimised encoding technique in tag design level and to find the best processing algorithm the chipless RFID signal in decoding level. In this paper, the reflection from a typical backscattered chipless RFID tag with six resonances is analysed, and different components of the signal are separated in both time and frequency domains. Moreover, the time domain signal corresponding to each resonator of the tag is studied. The data for this processing was captured from simulation in CST Microwave Studio 2017. The outcome of this study is understanding different components of a measured signal in a chipless RFID system and a discovering a research gap which is a need to find an optimum detection algorithm for tag ID extraction.

Keywords: antenna mode RCS, chipless RFID tag, resonance, structural mode RCS

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3831 Guidelines for School Management to Enhance School Engagement of Bangkok Christian College Students

Authors: Wichai Srisud, Shunnawat Pungbangkradee, Sukanya Chaemchoy

Abstract:

This research study aims to analyze and assess school management guidelines designed to enhance the level of Student School Engagement of students at Bangkok Christian College, according to three following primary objectives: 1) to evaluate the level of Student School Engagement among Bangkok Christian College students, 2) to examine the Priority Needs Index of school management for promoting an optimum level of Student School Engagement among Bangkok Christian College students, and 3) to develop additional guidelines for school management to further enhance the level of Student School Engagement of Bangkok Christian College students. The research was conducted using Explanatory Design research methodology, with data obtained from a sample comprised of 291 students and 6 administrative personnel. The research findings indicated that: 1) The overall level of Student School Engagement was high. Emotional engagement averaged at the highest level, followed by Behavioral Engagement and Cognitive Engagement, respectively. 2) The Priority Needs Index of school management for promoting Student School Engagement of Bangkok Christian College students was examined, revealing that Evaluation averaged at the highest PNI level, followed by Planning and Implementation, respectively. 3) Guidelines for school management to enhance Student School Engagement of Bangkok Christian College students should consist of four approaches: 3.1) A Cognitive Engagement Enhancing Approach, which must include (1) fostering students’ problem-solving flexibility, and their ability to devise solutions for overcoming potential challenges, and (2) encouraging students to deal effectively with academic setbacks, rather than becoming overwhelmed by what they may perceive as failures, 3.2) An Emotional Engagement Enhancing Approach, cultivating students’ interests, aspirations and goals in learning to maximize emotional investment in their academic pursuits, and 3.3) A Behavioral Engagement Enhancing Approach, for elevating students’ focus and attentiveness during learning, and improving their ability to avoid distractions during study time.

Keywords: school engagement, guidelines for school management

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3830 A Radiomics Approach to Predict the Evolution of Prostate Imaging Reporting and Data System Score 3/5 Prostate Areas in Multiparametric Magnetic Resonance

Authors: Natascha C. D'Amico, Enzo Grossi, Giovanni Valbusa, Ala Malasevschi, Gianpiero Cardone, Sergio Papa

Abstract:

Purpose: To characterize, through a radiomic approach, the nature of areas classified PI-RADS (Prostate Imaging Reporting and Data System) 3/5, recognized in multiparametric prostate magnetic resonance with T2-weighted (T2w), diffusion and perfusion sequences with paramagnetic contrast. Methods and Materials: 24 cases undergoing multiparametric prostate MR and biopsy were admitted to this pilot study. Clinical outcome of the PI-RADS 3/5 was found through biopsy, finding 8 malignant tumours. The analysed images were acquired with a Philips achieva 1.5T machine with a CE- T2-weighted sequence in the axial plane. Semi-automatic tumour segmentation was carried out on MR images using 3DSlicer image analysis software. 45 shape-based, intensity-based and texture-based features were extracted and represented the input for preprocessing. An evolutionary algorithm (a TWIST system based on KNN algorithm) was used to subdivide the dataset into training and testing set and select features yielding the maximal amount of information. After this pre-processing 20 input variables were selected and different machine learning systems were used to develop a predictive model based on a training testing crossover procedure. Results: The best machine learning system (three-layers feed-forward neural network) obtained a global accuracy of 90% ( 80 % sensitivity and 100% specificity ) with a ROC of 0.82. Conclusion: Machine learning systems coupled with radiomics show a promising potential in distinguishing benign from malign tumours in PI-RADS 3/5 areas.

Keywords: machine learning, MR prostate, PI-Rads 3, radiomics

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3829 Foreign Language Faculty Mentorship in Vietnam: An Interpretive Qualitative Study

Authors: Hung Tran

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This interpretive qualitative study employed three theoretical lenses: Bronfenbrenner’s (1979) Ecological System of Human Development, Vygotsky’s (1978) Sociocultural Theory of Development, and Knowles’s (1970) Adult Learning Theory as the theoretical framework in connection with the constructivist research paradigm to investigate into positive and negative aspects of the extant English as a Foreign Language (EFL) faculty mentoring programs at four higher education institutions (HEIs) in the Mekong River Delta (MRD) of Vietnam. Four apprentice faculty members (mentees), four experienced faculty members (mentors), and two associate deans (administrators) from these HEIs participated in two tape-recorded individual interviews in the Vietnamese language. Twenty interviews were transcribed verbatim and translated into English with verification. The initial analysis of data reveals that the mentoring program, which is mandated by Vietnam’s Ministry of Education and Training, has been implemented differently at these HEIs due to a lack of officially-documented mentoring guidance. Other general themes emerging from the data include essentials of the mentoring program, approaches of the mentoring practice, the mentee – mentor relationship, and lifelong learning beyond the mentoring program. Practically, this study offers stakeholders in the mentoring cycle description of benefits and best practices of tertiary EFL mentorship and a suggested mentoring program that is metaphorically depicted as “a lifebuoy” for its current and potential administrators and mentors to help their mentees survive in the first years of teaching. Theoretically, this study contributes to the world’s growing knowledge of post-secondary mentorship by enriching the modest literature on Asian tertiary EFL mentorship.

Keywords: faculty mentorship, mentees, mentors, administrator, the MRD, Vietnam

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3828 Designing, Manufacturing and Testing a Portable Tractor Unit Biocoal Harvester Combine of Agriculture and Animal Wastes

Authors: Ali Moharrek, Hosein Mobli, Ali Jafari, Ahmad Tabataee Far

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Biomass is a material generally produced by plants living on soil or water and their derivatives. The remains of agricultural and forest products contain biomass which is changeable into fuel. Besides, you can obtain biogas and ethanol from the charcoal produced from biomass through specific actions. this technology was designed for as a useful Native Fuel and Technology in Energy disasters Management Due to the sudden interruption of the flow of heat energy One of the problems confronted by mankind in the future is the limitations of fossil energy which necessitates production of new energies such as biomass. In order to produce biomass from the remains of the plants, different methods shall be applied considering factors like cost of production, production technology, area of requirement, speed of work easy utilization, ect. In this article we are focusing on designing a biomass briquetting portable machine. The speed of installation of the machine on a tractor is estimated as 80 MF 258. Screw press is used in designing this machine. The needed power for running this machine which is estimated as 17.4 kW is provided by the power axis of tractor. The pressing speed of the machine is considered to be 375 RPM Finally the physical and mechanical properties of the product were compared with utilized material which resulted in appropriate outcomes. This machine is designed for Gathering Raw materials of the ground by Head Section. During delivering the raw materials to Briquetting section, they Crushed, Milled & Pre Heated in Transmission section. This machine is a Combine Portable Tractor unit machine and can use all type of Agriculture, Forest & Livestock Animals Resides as Raw material to make Bio fuel. The Briquetting Section was manufactured and it successfully made bio fuel of Sawdust. Also this machine made a biofuel with Ethanol of sugarcane Wastes. This Machine is using P.T.O power source for Briquetting and Hydraulic Power Source for Pre Processing of Row Materials.

Keywords: biomass, briquette, screw press, sawdust, animal wastes, portable, tractors

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3827 Effects of Supplementary Cementitious Materials on Early Age Thermal Properties of Cement Paste

Authors: Maryam Ghareh Chaei, Masuzyo Chilwesa, Ali Akbarnezhad, Arnaud Castel, Redmond Lloyd, Stephen Foster

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Cement hydration is an exothermic chemical reaction generally leading to a rise in concrete’s temperature. This internal heating of concrete may, in turn, lead to a temperature difference between the hotter interior and the cooler exterior of concrete and thus differential thermal stresses in early ages which could be particularly significant in mass concrete. Such differential thermal stresses result in early age thermal cracking of concrete when exceeding the concrete’s tensile strength. The extent of temperature rise and thus early age differential thermal stresses is generally a function of hydration heat intensity, thermal properties of concrete and size of the concrete element. Both hydration heat intensity and thermal properties of concrete may vary considerably with variations in the type cementitious materials and other constituents. With this in mind, partial replacement of cement with supplementary cementitious materials including fly ash and ground granulated blast furnace slag has been investigated widely as an effective strategy to moderate the heat generation rate and thus reduce the risk of early age thermal cracking of concrete. However, there is currently a lack of adequate literature on effect of partial replacement of cement with fly ash and/or ground granulated blast furnace slag on the thermal properties of concrete. This paper presents the results of an experimental conducted to evaluate the effect of addition of varying percentages of fly ash (up to 60%) and ground granulated blast furnace slag (up to 50%) on the heat capacity and thermal conductivity of early age cement paste. The water to cementitious materials ratio is kept 0.45 for all the paste samples. The results of the experimental studies were used in a numerical analysis performed using Comsol Multiphysics to highlight the effects of variations in the thermal properties of concrete, due to variations in the type of aggregate and content of supplemenraty cementitious materials, on the risk of early age cracking of a concrete raft.

Keywords: thermal diffusivity, early age thermal cracking, concrete, supplementary cementitious materials

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3826 Comparative Therapeutic Effect of Acalypha indica Linn. Extract and Gemfibrozil on High Fructose and Cholesterol Diet Induced Pancreas Steatosis in Sprague-Dawley Mice

Authors: Adrian Reynaldo Sudirman, Siti Farida, Aisyah Aminy Maulidina, Caren Andika Surbakti

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Sedentary lifestyle and imbalance consumption pattern has made metabolic syndrome as the global time bomb phenomenon in the world. The increasing tendency of people in consuming high amount of fructose and cholesterol food has worsened this issue in the society. Pancreas steatosis become one of the most comorbid when early diagnosis and prompt treatment has not been applied on hyperglycemic and hyperlipidemic condition in metabolic syndrome patient. Gemfibrozil become the drug of choice to prevent this issue, yet the efficacy of this regiment was still questionable. Acalypha indica Linn. is the herb that has protective effect on hyperlipidemic and hyperglycemic condition. This study was aimed to compare therapeutic effect of gemfibrozil (G) and Acalypha indica Linn. (AI) on high fructose and cholesterol diet-induced pancreas steatosis in Sprague-Dawley mice. The post induction mice were divided into four groups: control, gemfibrozil, AI extract, and G+AI combination regiment. Each group received four weeks intervention. The result of statistical analysis using the One-Way ANOVA test and Tukey Post Hoc test showed significant decrease in pancreatic steatosis between the control group and administered Acalypha indica group (p = 0.004, 95% CI: 0.170-0.959) and the group administered with a combination of Gemfibrozil-Acalypha indica (p = 0.023, 95% CI: 0.537-0.813). The protective effect of Acalypha indica Linn. shows that this plant has the potential as therapeutic option in overcoming the condition of pancreas steatosis in metabolic syndrome.

Keywords: Acalypha Indica Linn., Cholesterol, Fructose, Gemfibrozil, Pancreas Steatosis

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3825 Heavy Sulphide Material Characterization of Grasberg Block Cave Mine, Mimika, Papua: Implication for Tunnel Development and Mill Issue

Authors: Cahya Wimar Wicaksono, Reynara Davin Chen, Alvian Kristianto Santoso

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Grasberg Cu-Au ore deposit as one of the biggest porphyry deposits located in Papua Province, Indonesia produced by several intrusion that restricted by Heavy Sulphide Zone (HSZ) in peripheral. HSZ is the rock that becomes the contact between Grassberg Igneous Complex (GIC) with sedimentary and igneous rock outside, which is rich in sulphide minerals such as pyrite ± pyrrhotite. This research is to obtain the characteristic of HSZ based on geotechnical, geochemical and mineralogy aspect and those implication for daily mining operational activities. Method used in this research are geological and alteration mapping, core logging, FAA (Fire Assay Analysis), AAS (Atomic absorption spectroscopy), RQD (Rock Quality Designation) and rock water content. Data generated from methods among RQD data, mineral composition and grade, lithological and structural geology distribution in research area. The mapping data show that HSZ material characteristics divided into three type based on rocks association, there are near igneous rocks, sedimentary rocks and on HSZ area. And also divided based on its location, north and south part of research area. HSZ material characteristic consist of rock which rich of pyrite ± pyrrhotite, and RQD range valued about 25%-100%. Pyrite ± pyrrhotite which outcropped will react with H₂O and O₂ resulting acid that generates corrosive effect on steel wire and rockbolt. Whereas, pyrite precipitation proses in HSZ forming combustible H₂S gas which is harmful during blasting activities. Furthermore, the impact of H₂S gas in blasting activities is forming poison gas SO₂. Although HSZ high grade Cu-Au, however those high grade Cu-Au rich in sulphide components which is affected in flotation milling process. Pyrite ± pyrrhotite in HSZ will chemically react with Cu-Au that will settle in milling process instead of floating.

Keywords: combustible, corrosive, heavy sulphide zone, pyrite ± pyrrhotite

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3824 Role of Matric Suction in Mechanics behind Swelling Characteristics of Expansive Soils

Authors: Saloni Pandya, Nikhil Sharma, Ajanta Sachan

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Expansive soils in the unsaturated state are part of vadose zone and encountered in several arid and semi-arid parts of the world. Influence of high temperature, low precipitation and alternate cycles of wetting and drying are responsible for the chemical weathering of rocks, which results in the formation of expansive soils. Shrinkage-swelling (expansive) soils cover a substantial portion of area in India. Damages caused by expansive soils to various geotechnical structures are alarming. Matric suction develops in unsaturated soil due to capillarity and surface tension phenomena. Matric suction influences the geometric arrangement of soil skeleton, which induces the volume change behaviour of expansive soil. In the present study, an attempt has been made to evaluate the role of matric suction in the mechanism behind swelling characteristics of expansive soil. Four different soils have been collected from different parts of India for the current research. Soil sample S1, S2, S3 and S4 were collected from Nagpur, Bharuch, Bharuch-Dahej highway and Ahmedabad respectively. DFSI (Differential Free Swell Index) of these soils samples; S1, S2, S3, and S4; were determined to be 134%, 104%, 70% and 30% respectively. X-ray diffraction analysis of samples exhibited that percentage of Montmorillonite mineral present in the soils reduced with the decrease in DFSI. A series of constant volume swell pressure tests and in-contact filter paper tests were performed to evaluate swelling pressure and matric suction of all four soils at 30% saturation and 1.46 g/cc dry density. Results indicated that soils possessing higher DFSI exhibited higher matric suction as compared to lower DFSI expansive soils. Significant influence of matric suction on swelling pressure of expansive soils was observed with varying DFSI values. Higher matric suction of soil might govern the water uptake in the interlayer spaces of Montmorillonite mineral present in expansive soil leading to crystalline swelling.

Keywords: differential free swell index, expansive soils, matric suction, swelling pressure

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3823 An Assessment of Finite Element Computations in the Structural Analysis of Diverse Coronary Stent Types: Identifying Prerequisites for Advancement

Authors: Amir Reza Heydari, Yaser Jenab

Abstract:

Coronary artery disease, a common cardiovascular disease, is attributed to the accumulation of cholesterol-based plaques in the coronary arteries, leading to atherosclerosis. This disease is associated with risk factors such as smoking, hypertension, diabetes, and elevated cholesterol levels, contributing to severe clinical consequences, including acute coronary syndromes and myocardial infarction. Treatment approaches such as from lifestyle interventions to surgical procedures like percutaneous coronary intervention and coronary artery bypass surgery. These interventions often employ stents, including bare-metal stents (BMS), drug-eluting stents (DES), and bioresorbable vascular scaffolds (BVS), each with its advantages and limitations. Computational tools have emerged as critical in optimizing stent designs and assessing their performance. The aim of this study is to provide an overview of the computational methods of studies based on the finite element (FE) method in the field of coronary stenting and discuss the potential for development and clinical application of stent devices. Additionally, the importance of assessing the ability of computational models is emphasized to represent real-world phenomena, supported by recent guidelines from the American Society of Mechanical Engineers (ASME). Validation processes proposed include comparing model performance with in vivo, ex-vivo, or in vitro data, alongside uncertainty quantification and sensitivity analysis. These methods can enhance the credibility and reliability of in silico simulations, ultimately aiding in the assessment of coronary stent designs in various clinical contexts.

Keywords: atherosclerosis, materials, restenosis, review, validation

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3822 The Cytoprotective Role of Antioxidants in Mammalian Cells Exposed to Variable Temperature, Pressure Overload and Radiation in the Stratosphere

Authors: Dawid Przystupski, Agata Gorska, Paulina Rozborska, Weronika Bartosik, Olga Michel, Joanna Rossowska, Anna Szewczyk, Malgorzata Drag-Zalesinska, Jedrzej Gorski, Julita Kulbacka

Abstract:

Researchers are still looking for an answer to the question which has been fascinating the mankind for generations, specifically – is there life beyond Earth? As long as routine flights to other planets remain beyond our reach, there is a need to find alternative ways to conduct the astrobiological research. It is worth noticing that the part of the Earth’s atmosphere, stratosphere, has been found to show subcosmic environmental conditions, namely temperatures around -50°C, very rarefied air, increased cosmic radiation and the Sun’s ultraviolet radiation. This phenomenon gives rise to the opportunity for the use of stratospheric environment as a research model for the space conditions. Therefore the idea of conducting astrobiological experiments during the stratospheric flights arose. Up to now, the preliminary work in this field included launching balloons containing solely microbiological samples into the stratosphere to figure out if they would be able to survive under the stratospheric conditions. In our study, we take this concept further, sending the human healthy and cancerous cells treated with various compounds to investigate whether these medicines are capable to protect the cells against stratospheric stress. Due to oxidative stress caused by ionizing radiation and temperature shock, we used natural compounds which display antioxidant properties. In this way, we were able to reduce the reactive oxygen species production affecting cells, which results in their death. After-flight laboratory tests of biological samples from the stratosphere have been performed and indicated the most active antioxidants as potential agents which can minimize the harmful impacts of stratospheric conditions, especially radiation and temperature.

Keywords: antioxidants, stratosphere, balloon flight, oxidative stress, cell death, radiation

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3821 LAMOS - Layered Amorphous Metal Oxide Gas Sensors: New Interfaces for Gas Sensing Applications

Authors: Valentina Paolucci, Jessica De Santis, Vittorio Ricci, Giacomo Giorgi, Carlo Cantalini

Abstract:

Despite their potential in gas sensing applications, the major drawback of 2D exfoliated metal dichalcogenides (MDs) is that they suffer from spontaneous oxidation in air, showing poor chemical stability under dry/wet conditions even at room temperature, limiting their practical exploitation. The aim of this work is to validate a synthesis strategy allowing microstructural and electrical stabilization of the oxides that inevitably form on the surface of 2D dichalcogenides. Taking advantage of spontaneous oxidation of MDs in air, we report on liquid phase exfoliated 2D-SnSe2 flakes annealed in static air at a temperature below the crystallization temperature of the native a-SnO2 oxide. This process yields a new class of 2D Layered Amorphous Metal Oxides Sensors (LAMOS), specifically few-layered amorphous a-SnO2, showing excellent gas sensing properties. Sensing tests were carried out at low operating temperature (i.e. 100°C) by exposing a-SnO2 to both oxidizing and reducing gases (i.e. NO2, H2S and H2) and different relative humidities ranging from 40% to 80% RH. The formation of stable nanosheets of amorphous a-SnO2 guarantees excellent reproducibility and stability of the response over one year. These results pave the way to new interesting research perspectives out considering the opportunity to synthesize homogeneous amorphous textures with no grain boundaries, no grains, no crystalline planes with different orientations, etc., following gas sensing mechanisms that likely differ from that of traditional crystalline metal oxide sensors. Moreover, the controlled annealing process could likely be extended to a large variety of Transition Metal Dichalcogenides (TMDs) and Metal Chalcogenides (MCs), where sulfur, selenium, or tellurium atoms can be easily displaced by O2 atoms (ΔG < 0), enabling the synthesis of a new family of amorphous interfaces.

Keywords: layered 2D materials, exfoliation, lamos, amorphous metal oxide sensors

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3820 Psychological Wellbeing of Caregivers: Findings from a Large Cohort of Thai Adults

Authors: Vasoontara Yiengprugsawan, Sam-ang Seubsman

Abstract:

As Thais live longer, caregivers will become even more important to social and healthcare systems. Commonly reported in many low and middle‐income countries in Asia, formal social welfare services to support caregivers are lacking and informal family support will be required for all levels of care. In 2005, 87,151 open‐university adults were recruited to the Thai Cohort Study, with the majority aged between 25 and 39 years, and residing nationwide. At the 4‐year follow up in 2009 (n=60569) and the 8‐year follow‐up in 2013 (n=42785), prospective cohort participants were asked if they provide care for chronically ill, disabled, or frail family members. Among Thai cohort members reporting between 2009 and 2013, approximately 56% were not caregivers in either year, 24.5% reported providing care in 2009 only, 8.6% in 2013 only, and 10.6% reported providing care at both time points. Caregivers in the cohort reported providing financial support, help with shopping, emotional support, and assist with daily activities. Kessler 6 psychological distress scale, measured in both 2009 and 2013, was used as the primary outcome of a relationship between caregiving status and mental health. Using multivariate logistic regression, our 4‐year longitudinal findings revealed that cohort members who reported providing care at both time points were 1.4 to 1.6 times more likely to report high psychological distress than non‐caregivers, after accounting for potential covariates. With increasing needs for informal care provided by family members, the future health and social welfare system will need to provide adequate support to caregivers (e.g., respite care, clinical support and information for the family, and awareness of mental health among caregivers).

Keywords: family caregivers, psychological distress, prospective cohort, longitudinal study, Thailand

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3819 Exploring the Stressors Faced by Sportspersons: A Qualitative Study on Young Indian Sportspersons and Their Coping Strategies to Stress

Authors: Moyera Sanganeria

Abstract:

In the highly competitive landscape of contemporary sports, sportspersons worldwide encounter formidable challenges, often practicing for extensive hours while contending with limited social and physical resources. A growing number of sportspersons globally are sharing their struggles with depression, anxiety, and stress arising from the complex journey and identity associated with being a sportsperson. This qualitative study aims to investigate the challenges faced by sportspersons in individual versus team sports and explore potential gender-based variations in coping strategies. It attempts to do so by recognizing the imperative to comprehend the root causes and coping mechanisms for these stressors. By employing purposive sampling, MMA and Kabaddi players from training academies across Mumbai were selected for the study. Twelve participants were interviewed through semi-structured interviews guided by an interview guide. Reflective thematic analysis was employed to discern diverse stressors and coping strategies. Key stressors encountered by young Indian sportspersons encompass injuries, socio-economic challenges, financial constraints, escalating competition, and performance anxiety. Notably, individuals engaged in team sports tended to adopt emotion-focused coping mechanisms, while those in individual sports leaned more towards problem-focused coping strategies in response to these stressors. There were no prominent gender differences found in coping strategies employed by sportspersons. This study underscores the critical issue of declining mental health among sportspersons in India, emphasizing the necessity for a structured and customized mental health intervention strategy tailored to the unique needs of this population.

Keywords: stressors, coping strategies, sports psychology, sportspersons, mental health

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3818 Record Peak Current Density in AlN/GaN Double-Barrier Resonant Tunneling Diodes on Free-Standing Gan Substrates by Modulating Barrier Thickness

Authors: Fang Liu, Jia Jia Yao, Guan Lin Wu, Ren Jie Liu, Zhuang Guo

Abstract:

Leveraging plasma-assisted molecular beam epitaxy (PA-MBE) on c-plane free-standing GaN substrates, this work demonstrates high-performance AlN/GaN double-barrier resonant tunneling diodes (RTDs) featuring stable and repeatable negative differential resistance (NDR) characteristics at room temperature. By scaling down the barrier thickness of AlN and the lateral mesa size of collector, a record peak current density of 1551 kA/cm2 is achieved, accompanied by a peak-to-valley current ratio (PVCR) of 1.24. This can be attributed to the reduced resonant tunneling time under thinner AlN barrier and the suppressed external incoherent valley current by reducing the dislocation number contained in the RTD device with the smaller size of collector. Statistical analysis of the NDR performance of RTD devices with different AlN barrier thicknesses reveals that, as the AlN barrier thickness decreases from 1.5 nm to 1.25 nm, the average peak current density increases from 145.7 kA/cm2 to 1215.1 kA/cm2, while the average PVCR decreases from 1.45 to 1.1, and the peak voltage drops from 6.89 V to 5.49 V. The peak current density obtained in this work represents the highest value reported for nitride-based RTDs to date, while maintaining a high PVCR value simultaneously. This illustrates that an ultra-scaled RTD based on a vertical quantum-well structure and lateral collector size is a valuable approach for the development of nitride-based RTDs with excellent NDR characteristics, revealing their great potential applications in high-frequency oscillation sources and high-speed switch circuits.

Keywords: GaN resonant tunneling diode, peak current density, peak-to-valley current ratio, negative differential resistance

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3817 Core-Shell Type Magnetic Nanoparticles for Targeted Drug Delivery

Authors: Yogita Patil-Sen

Abstract:

Magnetic nanoparticles such as those made of iron oxide have been widely explored as biocatalysts, contrast agents, and drug delivery systems. However, some of the challenges associated with these particles are agglomeration and biocompatibility, which lead to concern of toxicity of the particles, especially for drug delivery applications. Coating the particles with biocompatible materials such as lipids and peptides have shown to improve the mentioned issues. Thus, these core-shell type nanoparticles are emerging as the new class of nanomaterials for targeted drug delivery applications. In this study, various types of core-shell magnetic nanoparticles are prepared and characterized using techniques, such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM) and Thermogravimetric Analysis (TGA). The heating ability of nanoparticles is tested under oscillating magnetic field. The efficacy of the nanoparticles as drug carrier is also investigated. The loading of an anticancer drug, Doxorubicin at 18 °C is measured up to 48 hours using UV-visible spectrophotometer. The drug release profile is obtained under thermal incubation condition at 37 °C and compared with that under the influence of oscillating field. The results suggest that the core-shell nanoparticles exhibit superparamagnetic behaviour, although, coating reduces the magnetic properties of the particles. Both the uncoated and coated particles show good heating ability, again it is observed that coating decreases the heating behaviour of the particles. However, coated particles show higher drug loading efficiency than the uncoated particles and the drug release is much more controlled under the oscillating magnetic field. Thus, the results strongly indicate the suitability of the prepared core-shell type nanoparticles as drug delivery vehicles and their potential in magnetic hyperthermia applications and for hyperthermia cancer therapy.

Keywords: core-shell, hyperthermia, magnetic nanoparticles, targeted drug delivery

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3816 Engineering Ligand-Free Biodegradable-Based Nanoparticles for Cell Attachment and Growth

Authors: Simone F. Medeiros, Isabela F. Santos, Rodolfo M. Moraes, Jaspreet K. Kular, Marcus A. Johns, Ram Sharma, Amilton M. Santos

Abstract:

Tissue engineering aims to develop alternatives to treat damaged tissues by promoting their regeneration. Its basic principle is to place cells on a scaffold capable of promoting cell functions, and for this purpose, polymeric nanoparticles have been successfully used due to the ability of some macro chains to mimic the extracellular matrix and influence cell functions. In general, nanoparticles require surface chemical modification to achieve cell adhesion, and recent advances in their synthesis include methods for modifying the ligand density and distribution onto nanoparticles surface. However, this work reports the development of biodegradable polymeric nanoparticles capable of promoting cellular adhesion without any surface chemical modification by ligands. Biocompatible and biodegradable nanoparticles based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) were synthesized by solvent evaporation method. The produced nanoparticles were small in size (85 and 125 nm) and colloidally stable against time in aqueous solution. Morphology evaluation showed their spherical shape with small polydispersity. Human osteoblast-like cells (MG63) were cultured in the presence of PHBHV nanoparticles, and growth kinetics were compared to those grown on tissue culture polystyrene (TCPS). Cell attachment on non-tissue culture polystyrene (non-TCPS) pre-coated with nanoparticles was assessed and compared to attachment on TCPS. These findings reveal the potential of PHBHV nanoparticles for cell adhesion and growth, without requiring a matrix ligand to support cells, to be used as scaffolds, in tissue engineering applications.

Keywords: tissue engineering, PHBHV, stem cells, cellular attachment

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3815 Rare-Earth Ions Doped Zirconium Oxide Layers for Optical and Photovoltaic Applications

Authors: Sylwia Gieraltowska, Lukasz Wachnicki, Bartlomiej S. Witkowski, Marek Godlewski

Abstract:

Oxide layers doped with rare-earth (RE) ions in optimized way can absorb short (ultraviolet light), which will be converted to visible light by so-called down-conversion. Down-conversion mechanisms are usually exploited to modify the incident solar spectrum. In down conversion, multiple low-energy photons are generated to exploit the energy of one incident high-energy photon. These RE-doped oxide materials have attracted a great deal of attention from researchers because of their potential for optical manipulation in optical devices (detectors, temperature sensors, and compact solid-state lasers, light-emitting diodes), bio-analysis, medical therapy, display technologies, and light harvesting (such as in photovoltaic cells). The zirconium dioxide (ZrO2) doped RE ions (Eu, Tb, Ce) multilayer structures were tested as active layers, which can convert short wave emission to light in the visible range (the down-conversion mechanism). For these applications original approach of deposition ZrO2 layers using the Atomic Layer Deposition (ALD) method and doping these layers with RE ions using the spin-coating technique was used. ALD films are deposited at relatively low temperature (well below 250°C). This can be an effective method to achieve the white-light emission and to improve on this way light conversion efficiency, by an extension of absorbed spectral range by a solar cell material. Photoluminescence (PL), X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscope (AFM) measurement are analyzed. The research was financially supported by the National Science Centre (decision No. DEC-2012/06/A/ST7/00398 and DEC- 2013/09/N/ST5/00901).

Keywords: ALD, oxide layers, photovoltaics, thin films

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3814 Growth Studies and Leaf Mineral Composition of Amaranthus hybridus L. in Soil Medium Supplemended with Palm Bunch Ash Extract from Elaeis Guineensis jacq. in Abak Agricultural Zone of Akwa Ibom State, Nigeria

Authors: Etukudo, M. Mbosowo, Nyananyo, L. Bio, Negbenebor, A. Charles

Abstract:

An aqueous extract of palm bunch ash from Elaeis guineensis Jacq., equilibrated with water was used to assess the growth and minerals composition of Amaranthus hybridus L. in agricultural soil of Abak, Akwa Ibom State, nigeria. Various concentrations, 0 (control), 10, 20, 30, 40, and 50% of palm bunch extract per 4kg of sandy-loam soil were used for the study. Chemical characteristics of the extract, Growth parameters (Plant height, root length, fresh weight, dry weight and moisture content), leaf minerals composition (Nitrogen, phosphorus, potassium, calcium and magnesium) of the crop and soil chemical composition before and after harvest (pH, organic matter, nitrogen, phosphorus, potassium, calcium and magnesium) were examined. The results showed that palm bunch ash extract significantly (P < 0.05) increased the soil pH at all levels of treatments compared to the control. Similarly, the soil and leaf minerals component (N, P, K. Ca, and Mg) of the crop increased with increase in the concentration of palm bunch extract, except at 40 and 50% for leaf minerals composition, Soil organic matter, nitrogen and phosphorus J(before and after harvest). In addition, The plant height, Root length, fresh weight, dry weight and moisture content of the crop increased significantly (P < 0.05) with increase in the concentration of the extract, Except at 30, 40 and 50% where these growth parameters decreased in relation to the control treatment. Therefore, this study suggests that palm bunch ash extract could be utilized at lower concentration as a nutrient supplement for both Amaranthus hubridus L. and soil medium, most especially in the tropical soils of the Niger Delta region of Nigeria.

Keywords: Amaranthus hybridus L., growth, leaf minerals composition, palm bunch ash extract

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3813 Multi-Particle Finite Element Modelling Simulation Based on Cohesive Zone Method of Cold Compaction Behavior of Laminar Al and NaCl Composite Powders

Authors: Yanbing Feng, Deqing Mei, Yancheng Wang, Zichen Chen

Abstract:

With the advantage of low volume density, high specific surface area, light weight and good permeability, porous aluminum material has the potential to be used in automotive, railway, chemistry and construction industries, etc. A layered powder sintering and dissolution method were developed to fabricate the porous surface Al structure with high efficiency. However, the densification mechanism during the cold compaction of laminar composite powders is still unclear. In this study, multi particle finite element modelling (MPFEM) based on the cohesive zone method (CZM) is used to simulate the cold compaction behavior of laminar Al and NaCl composite powders. To obtain its densification mechanism, the macro and micro properties of final compacts are characterized and analyzed. The robustness and accuracy of the numerical model is firstly verified by experimental results and data fitting. The results indicate that the CZM-based multi particle FEM is an effective way to simulate the compaction of the laminar powders and the fracture process of the NaCl powders. In the compaction of the laminar powders, the void is mainly filled by the particle rearrangement, plastic deformation of Al powders and brittle fracture of NaCl powders. Large stress is mainly concentrated within the NaCl powers and the contact force network is formed. The Al powder near the NaCl powder or the mold has larger stress distribution on its contact surface. Therefore, the densification process of cold compaction of laminar Al and NaCl composite powders is successfully analyzed by the CZM-based multi particle FEM.

Keywords: cold compaction, cohesive zone, multi-particle FEM, numerical modeling, powder forming

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3812 The Impact of Dispatching with Rolling Horizon Control in Sizing Thermal Storage for Solar Tower Plant Participating in Wholesale Spot Electricity Market

Authors: Navid Mohammadzadeh, Huy Truong-Ba, Michael Cholette

Abstract:

The solar tower (ST) plant is a promising technology to exploit large-scale solar irradiation. With thermal energy storage, ST plant has the potential to shift generation to high electricity price periods. However, the size of storage limits the dispatchability of the plant, particularly when it should compete with uncertainty in forecasts of solar irradiation and electricity prices. The purpose of this study is to explore the size of storage when Rolling Horizon Control (RHC) is employed for dispatch scheduling. To this end, RHC is benchmarked against perfect knowledge (PK) forecast and two day-ahead dispatching policies. With optimisation of dispatch planning using PK policy, the optimal achievable profit for a specific size of the storage is determined. A sensitivity analysis using Monte-Carlo simulation is conducted, and the size of storage for RHC and day-ahead policies is determined with the objective of reaching the profit obtained from the PK policy. A case study is conducted for a hypothetical ST plant with thermal storage located in South Australia and intends to dispatch under two market scenarios: 1) fixed price and 2) wholesale spot price. The impact of each individual source of uncertainty on storage size is examined for January and August. The exploration of results shows that dispatching with RH controller reaches optimal achievable profit with ~15% smaller storage compared to that in day-ahead policies. The results of this study may be applied to the CSP plant design procedure.

Keywords: solar tower plant, spot market, thermal storage system, optimized dispatch planning, sensitivity analysis, Monte Carlo simulation

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