Search results for: energy transfer

Authors: Ajay Kumar, Neha Gupta

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This work presents the sensitivity assessment of Gallium Nitride (GaN) material-based FinFET by dielectric modulation in the nanocavity gap for label-free biosensing applications. The significant deflection is observed in the electrical characteristics such as drain current (ID), transconductance (gm), surface potential, energy band profile, electric field, sub-threshold slope (SS), and threshold voltage (Vth) in the presence of biomolecules owing to GaN material. Further, the device sensitivity is evaluated to identify the effectiveness of the proposed biosensor and its capability to detect the biomolecules with high precision or accuracy. Higher sensitivity is observed for Gelatin (k=12) in terms of on-current (SION), threshold voltage (SVth), and switching ratio (SSR) by 104.88%, 82.12%, and 119.73%, respectively. This work is performed using a powerful tool 3D Sentaurus TCAD using a well-calibrated structure. All the results pave the way for GaN-FinFET as a viable candidate for label-free dielectric modulated biosensor applications.

Keywords: biosensor, biomolecules, FinFET, sensitivity

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Authors: Kamal Kumar Gupta

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The present research work was carried out on Dysdercus koenigii to understand various aspects of reproductive behavior such as mate finding and recognition, mate selection and mating preference, mating receptivity, and prolonged copulation. The studies carried out on mate searching and courtship behaviour of Dysdercus reflected the courtship behaviour in Dysdercus was brief. The opposite sexes are brought together by the pheromone. The males responded to female sex pheromones by showing directional movements toward the sex partners. Change in mating receptivity pattern of female Dysdercus was ascertained using three parameters of mating behaviour i.e. numbers of male’s encounter, the time taken to mate successfully and per cent females responding to mating. It was seen that a receptive female responded positively to the courting males and a high percentage of females mate usually in a very short time span. The females of Dysdercus showed continued mating receptivity throughout their life. The studies pertaining to mate selection by females showed that females generally do not discriminate among males and usually mate with any male they encountered first. The adults of Dysdercus remain in continuous copula up to 72hr. and mate 5-7 time in their life span. Studies pertaining to significance of prolonged mating in the life time reproductive success of the female Dysdercus indicated that fecundity and fertility and oviposition behavior of the female Dysdercus was related to duration of mating. In order to understand sperm precedence, the sterilized males were produced by exposing them to Gamma radiation. Our studies indicated that a dose of 50 Gy of Gamma radiations induced 95% sterility but does not impair the mating behaviour drastically. To understand role of sperms which were transfer during second mating in fertilizing the subsequent egg batches the sperm utilization pattern of doubly mated female was assessed. The females were mated with normal male or sterilized male in a combination. The sperm utilization pattern was determined by P2 value, our studies indicated a very high P2 value of 0.966, and indicated that sperms of last mating were utilized by the female for fertilization. In light of some of the unique reproductive behaviour of Dysdercus koenigii, such as brief courtship behavior, generalized mate selection by the female, continued mating receptivity and a prolonged pre oviposition period, the present studies on sperm precedence provides an explanation to an unusually prolonged copulation in Dysdercus.

Keywords: dysdercus koenigii, mating behaviour, reproductive performance, entomology

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Authors: Beihai Xiong, Dengke Hua, Wouter Hendriks, Wilbert Pellikaan

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To improve the energy status of dairy cows in the early lactation, lots of jobs have been done on adjusting the starch to fiber ratio in the diet. As a complex ecosystem, the rumen contains a large population of microorganisms which plays a crucial role in feed degradation. Further study on the microbiota alterations and metabolic changes under different dietary energy sources is essential and valuable to better understand the function of the ruminal microorganisms and thereby to optimize the rumen function and enlarge feed efficiency. The present study will focus on the effects of two glucogenic diets (G: ground corn and corn silage; S: steam-flaked corn and corn silage) and a lipogenic diet (L: sugar beet pulp and alfalfa silage) on rumen fermentation, gas production, the ruminal microbiota and metabolome, and also their correlations in vitro. The gas production was recorded consistently, and the gas volume and producing rate at times 6, 12, 24, 48 h were calculated separately. The fermentation end-products were measured after fermenting for 48 h. The ruminal bacteria and archaea communities were determined by 16S RNA sequencing technique, the metabolome profile was tested through LC-MS methods. Compared to the diet G and S, the L diet had a lower dry matter digestibility, propionate production, and ammonia-nitrogen concentration. The two glucogenic diets performed worse in controlling methane and lactic acid production compared to the L diet. The S diet produced the greatest cumulative gas volume at any time points during incubation compared to the G and L diet. The metabolic analysis revealed that the lipid digestion was up-regulated by the diet L than other diets. On the subclass level, most metabolites belonging to the fatty acids and conjugates were higher, but most metabolites belonging to the amino acid, peptides, and analogs were lower in diet L than others. Differences in rumen fermentation characteristics were associated with (or resulting from) changes in the relative abundance of bacterial and archaeal genera. Most highly abundant bacteria were stable or slightly influenced by diets, while several amylolytic and cellulolytic bacteria were sensitive to the dietary changes. The L diet had a significantly higher number of cellulolytic bacteria, including the genera of Ruminococcus, Butyrivibrio, Eubacterium, Lachnospira, unclassified Lachnospiraceae, and unclassified Ruminococcaceae. The relative abundances of amylolytic bacteria genera including Selenomonas_1, Ruminobacter, and Succinivibrionaceae_UCG-002 were higher in diet G and S. These affected bacteria was also proved to have high associations with certain metabolites. The Selenomonas_1 and Succinivibrionaceae_UCG-002 may contribute to the higher propionate production in the diet G and S through enhancing the succinate pathway. The results indicated that the two glucogenic diets had a greater extent of gas production, a higher dry matter digestibility, and produced more propionate than diet L. The steam-flaked corn did not show a better performance on fermentation end-products than ground corn. This study has offered a deeper understanding of ruminal microbial functions which could assistant the improvement in rumen functions and thereby in the ruminant production.

Keywords: gas production, metabolome, microbiota, rumen fermentation

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Authors: Chonmapat Torasa

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This paper presents the performance of electricity generation and consumption from solar generator installed at Rajabhat Suan Sunandha’s learning center in Samutsongkram. The result from the experiment showed that solar cell began to work and distribute the current into the system when the solar energy intensity was 340 w/m2, starting from 8:00 am to 4:00 pm (duration of 8 hours). The highest intensity read during the experiment was 1,051.64w/m2. The solar power was 38.74kWh/day. The electromotive force from solar cell averagely was 93.6V. However, when connecting solar cell with the battery charge controller system, the voltage was dropped to 69.07V. After evaluating the power distribution ability and electricity load of tested solar cell, the result showed that it could generate power to 11 units of 36-wattfluorescent lamp bulbs, which was altogether 396W. In the meantime, the AC to DC power converter generated 3.55A to the load, and gave 781VA.

Keywords: solar cell, solar-cell power generating system, computer, systems engineering

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Authors: Maha BenHamad, Ali Snoussi, Ammar Ben Brahim

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A steady-state analysis of triple-effect thermal vapor compressor desalination unit was performed. A mathematical model based on mass, salinity and energy balances is developed. The purpose of this paper is to develop a connection between process simulator and process optimizer in order to study the influence of several operating variables on the performance and the produced water cost of the unit. A MATLAB program is used to solve the model equations, and Aspen HYSYS is used to model the plant. The model validity is examined against a commercial plant and showed a good agreement between industrial data and simulations results. Results show that the pressures of the last effect and the compressed vapor have an important influence on the produced cost, and the increase of the difference temperature in the condenser decreases the specific heat area about 22%.

Keywords: steady-state, triple effect, thermal vapor compressor, Matlab, Aspen Hysys

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Authors: Paul Onyegbule, Harjit Singh

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Vacuum glazing is an innovative transparent thermal insulator that has application in high performance window, especially in renewable energy. Different materials as well as sealing methods have been adopted to seal windows with different temperatures. The impact of temperatures on sealing layers has been found to have significant effects on the microstructure of the seal. This paper seeks to investigate the effects of sealing materials specifically glass powder and flux compound (borax) for vacuum glazing. The findings of the experiment conducted show that the sealing material was rigid with some leakage around the edge, and we found that this could be stopped by enhancing the uniformity of the seal within the periphery. Also, we found that due to the intense tensile stress from the oven surface temperature of the seal at 200 ⁰C, a crack was observed at the side of the glass. Based on the above findings, this study concludes that a glass powder with a lower melting temperature of below 250 ⁰C with the addition of an adhesive (borax flux) should be used for future vacuum seals.

Keywords: double glazed windows, U-value, heat loss, borax powder, edge seal

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Authors: Mohammed A. Sakr, Tarek M. Khalifa, Walid N. Mansour

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Fiber reinforced polymer (FRP) installation is a very effective way to repair and strengthen structures that have become structurally weak over their life span. This technique attracted the concerning of researchers during the last two decades. This paper presents a simple uniaxial nonlinear finite element model (UNFEM) able to accurately estimate the load-carrying capacity, different failure modes and the interfacial stresses of reinforced concrete (RC) continuous beams flexurally strengthened with externally bonded FRP plates on the upper and lower fibers. Results of the proposed finite element (FE) model are verified by comparing them with experimental measurements available in the literature. The agreement between numerical and experimental results is very good. Considering fracture energy of adhesive is necessary to get a realistic load carrying capacity of continuous RC beams strengthened with FRP. This simple UNFEM is able to help design engineers to model their strengthened structures and solve their problems.

Keywords: continuous beams, debonding, finite element, fibre reinforced polymer

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Authors: Caixia Gao, Chuanrong Li, Lingli Tang, Lingling Ma, Yaokai Liu, Xinhong Wang, Yongsheng Zhou

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Performances analysis of remote sensing sensor is required to pursue a range of scientific research and application objectives. Laboratory analysis of any remote sensing instrument is essential, but not sufficient to establish a valid inflight one. In this study, with the aid of the in situ measurements and corresponding image of three-gray scale permanent artificial target, the in-flight radiometric performances analyses (in-flight radiometric calibration, dynamic range and response linearity, signal-noise-ratio (SNR), radiometric resolution) of self-developed short-wave infrared (SWIR) camera are performed. To acquire the inflight calibration coefficients of the SWIR camera, the at-sensor radiances (L_i) for the artificial targets are firstly simulated with in situ measurements (atmosphere parameter and spectral reflectance of the target) and viewing geometries using MODTRAN model. With these radiances and the corresponding digital numbers (DN) in the image, a straight line with a formulation of L = G × DN + B is fitted by a minimization regression method, and the fitted coefficients, G and B, are inflight calibration coefficients. And then the high point (L_H) and the low point (L_L) of dynamic range can be described as L_H= (G × DN_H + B) and L_L= B, respectively, where DN_H is equal to 2ⁿ − 1 (n is the quantization number of the payload). Meanwhile, the sensor’s response linearity (δ) is described as the correlation coefficient of the regressed line. The results show that the calibration coefficients (G and B) are 0.0083 W·sr⁻¹m⁻²µm⁻¹ and −3.5 W·sr⁻¹m⁻²µm⁻¹; the low point of dynamic range is −3.5 W·sr⁻¹m⁻²µm⁻¹ and the high point is 30.5 W·sr⁻¹m⁻²µm⁻¹; the response linearity is approximately 99%. Furthermore, a SNR normalization method is used to assess the sensor’s SNR, and the normalized SNR is about 59.6 when the mean value of radiance is equal to 11.0 W·sr⁻¹m⁻²µm⁻¹; subsequently, the radiometric resolution is calculated about 0.1845 W•sr^-1m^-2μm^-1. Moreover, in order to validate the result, a comparison of the measured radiance with a radiative-transfer-code-predicted over four portable artificial targets with reflectance of 20%, 30%, 40%, 50% respectively, is performed. It is noted that relative error for the calibration is within 6.6%.

Keywords: calibration and validation site, SWIR camera, in-flight radiometric calibration, dynamic range, response linearity

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Authors: H. Chabalala, A. Grootboom, M. Tang

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The innovative development, production, and clinical utilisation of African natural medicines requires frameworks from systematisation, innovation, registration. Afrika faces challenges when it comes to these sectors. The opposite is the case as is is evident in ancient Asian (Traditional Chinese Medicine and Indian Ayurveda and Siddha) medical systems, which are interfaced into their respective national health and educational systems. Afrikan Natural Medicines (ANMs) are yet to develop systematisation frameworks, i.e. disease characterisation and medicines classification. This paper explores classical medical systems drawn from Afrikan and Chinese experts in natural medicines. An Afrikological research methodology was used to conduct in-depth interviews with 20 key respondents selected through purposeful sampling technique. Data was summarised into systematisation frameworks for classical disease theories, patient categorisation, medicine classification, aetiology and pathogenesis of disease, diagnosis and prognosis techniques and treatment methods. It was discovered that ancient Afrika had systematic medical cosmologies, remnants of which are evident in most Afrikan cultural health practices. Parallels could be drawn from classical medical concepts of antiquity, like Chinese Taoist and Indian tantric health systems. Data revealed that both the ancient and contemporary ANM systems were based on living medical cosmologies. The study showed that African Natural Healing Systems have etiological systems, general pathogenesis knowledge, differential diagnostic techniques, comprehensive prognosis and holistic treatment regimes. Systematisation models were developed out of these frameworks, and this could be used for evaluation of clinical research, medical application including development of curriculum for high-education. It was envisaged that frameworks will pave way towards the development, production and commercialisation of ANMs. This was piloted in inclusive innovation, technology transfer and commercialisation of South African natural medicines, cosmeceuticals, nutraceuticals and health infusions. The central model presented here in will assist in curriculum development and establishment of Afrikan Medicines Hospitals and Pharmaceutical Industries.

Keywords: African Natural Medicines, Indigenous Knowledge Systems, Medical Cosmology, Clinical Application

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Authors: V. Lokesh, M. Manjunathan, S. Sairam, K. Saithsh Kumar, R. Anantharaj

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The densities of pure and its binary mixtures of 1-Butyl-3-methyl imidazolium bis (trifluoro methyl sulfonyl) imide and 1–Ethyl-3-methyl imidazolium ethyl sulphate at different temperature, over the entire composition range were measured at 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, 323.15, 328.15, 33.15, 338.15, 343.15 K. In this study, the liquid-liquid extraction procedure was used. From this experimental data, the excess molar volumes, apparent molar volume, partial molar volumes and the excess partial molar volumes have been calculated for over the whole composition range. Hence, the effect of temperature and composition on all derived thermodynamic properties of this binary mixture will be discussed in terms of intermolecular interactions.

Keywords: ionic liquid, interaction energy, effect of temperature, effect of composition

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Authors: Huy Q. Tran, Jungwon Huh, Kiseok Kwak, Choonghyun Kang

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Infrared thermography (IRT) technique has been proven to be a good method for nondestructive evaluation of concrete material. In the building, a broad range of applications has been used such as subsurface defect inspection, energy loss, and moisture detection. The purpose of this research is to consider the qualitative and quantitative performance of reinforced concrete deteriorations using active infrared thermography technique. An experiment of three different heating regimes was conducted on a concrete slab in the laboratory. The thermal characteristics of the IRT method, i.e., absolute contrast and observation time, are investigated. A linear relationship between the observation time and the real depth was established with a well linear regression R-squared of 0.931. The results showed that the absolute contrast above defective area increases with the rise of the size of delamination and the heating time. In addition, the depth of delamination can be predicted by using the proposal relationship of this study.

Keywords: concrete building, infrared thermography, nondestructive evaluation, subsurface delamination

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Authors: L. Foudia, K. Haddadi, M. Reffas

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First principles study of structural, elastic, electronic and optical properties of the monoclinic perovskite type ScRhO₃ has been reported using the pseudo-potential plane wave method within the local density approximation. The calculated lattice parameters, including the lattice constants and angle β are in excellent agreement with the available experimental data, which proving the reliability of the chosen theoretical approach. Pressure dependence up to 20 GPa of the single crystal and polycrystalline elastic constants has been investigated in details using the strain-stress approach. The mechanical stability, ductility, average elastic wave velocity, Debye temperature and elastic anisotropy were also assessed. Electronic band structure and density of states (DOS) demonstrated its semiconducting nature showing a direct band gap of 1.38 eV. Furthermore, several optical properties, such as absorption coefficient, reflectivity, refractive index, dielectric function, optical conductivity and electron energy loss function have been calculated for radiation up to 40 eV.

Keywords: ab-initio, perovskite, DFT, band gap.

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Authors: Zhuang Ma, Zihan Zhang, Yu Li

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Environmental concerns from stakeholders (e.g., governments & customers) have pushed firms to integrate environmental management systems into business processes such as R&D, manufacturing, and marketing. Environmental systems include managing environmental risks and pollution control (e.g., air pollution control, waste-water treatment, noise control, energy recycling & solid waste treatment) through raw material management, the elimination and reduction of contaminants, recycling, and reuse in firms' operational processes. Despite increasing studies on firms' proactive adoption of environmental management, their focus is primarily on large corporations operating in developed economies. Investigations in the environmental management efforts of small and medium-sized enterprises (SMEs) are scarce. This is problematic for SMEs because, unlike large corporations, SMEs have limited awareness, resources, capabilities to adapt their operational routines to address environmental impacts. The purpose of this study is to explore how SMEs develop organizational capabilities through interactions with business partners (e.g., environmental management specialists & customers). Drawing on the resource-based view (RBV) and an organizational capabilities perspective, this study investigates the interactively developed capabilities that allow SMEs to adopt environmental management systems. Using an exploratory approach, the study includes 12 semi-structured interviews with senior managers from four SMEs, two environmental management specialists, and two customers in the pharmaceutical sector in Chongqing, China. Findings of this study include four key organizational capabilities: 1) ‘dynamic marketing’ capability, which allows SMEs to recoup the investments in environmental management systems by developing environmentally friendly products to address customers' ever-changing needs; 2) ‘process improvement’ capability, which allows SMEs to select and adopt the latest technologies from biology, chemistry, new material, and new energy sectors into the production system for improved environmental performance and cost-reductions; and 3) ‘relationship management’ capability which allows SMEs to improve corporate image among the public, social media, government agencies, and customers, who in turn help SMEs to overcome their competitive disadvantages. These interactively developed capabilities help SMEs to address larger competitors' foothold in the local market, reduce market constraints, and exploit competitive advantages in other regions (e.g., Guangdong & Jiangsu) of China. These findings extend the RBV and organizational capabilities perspective; that is, SMEs can develop the essential resources and capabilities required for environmental management through interactions with upstream and downstream business partners. While a limited number of studies did highlight the importance of interactions among SMEs, customers, suppliers, NGOs, industrial associations, and consulting firms, they failed to explore the specific capabilities developed through these interactions. Additionally, the findings can explain how a proactive adoption of environmental management systems could help some SMEs to overcome the institutional and market restraints on their products, thereby springboarding into larger, more environmentally demanding, yet more profitable markets compared with their existing market.

Keywords: capabilities, environmental management systems, interactions, SMEs

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Authors: Getahun Nigusie Demise

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Background; antiretroviral treatment reduce HIV-related morbidity, and prolonged survival of patients however, there is lack of up-to-date information concerning the treatment long term effect on the survival of HIV positive children especially in the study area. Objective: The aim of this study is to assess the incidence and predictors of mortality among HIV positive children on antiretroviral therapy (ART) in public hospitals of Harer town who were enrolled from 2011 to 2021. Methodology: Institution based retrospective cohort study was conducted among 429 HIV positive children enrolled in ART clinic from January 1st 2011 to December30th 2021. Data were collected from medical cards by using a data extraction form, Descriptive analyses were used to Summarized the results, and life table was used to estimate survival probability at specific point of time after introduction of ART. Kaplan Meier survival curve together with log rank test was used to compare survival between different categories of covariates, and Multivariate Cox-proportional hazard regression model was used to estimate adjusted Hazard rate. Variables with p-values ≤0.25 in bivariable analysis were candidates to the multivariable analysis. Finally, variables with p-values < 0.05 were considered as significant variables. Results: The study participants had followed for a total of 2549.6 child-years (30596 child months) with an overall mortality rate of 1.5 (95% CI: 1.1, 2.04) per 100 child-years. Their median survival time was 112 months (95% CI: 101–117). There were 38 children with unknown outcome, 39 deaths, and 55 children transfer out to different facility. The overall survival at 6, 12, 24, 48 months were 98%, 96%, 95%, 94% respectively. being in WHO clinical Stage four (AHR=4.55, 95% CI:1.36, 15.24), having anemia(AHR=2.56, 95% CI:1.11, 5.93), baseline low absolute CD4 count (AHR=2.95, 95% CI: 1.22, 7.12), stunting (AHR=4.1, 95% CI: 1.11, 15.42), wasting (AHR=4.93, 95% CI: 1.31, 18.76), poor adherence to treatment (AHR=3.37, 95% CI: 1.25, 9.11), having TB infection at enrollment (AHR=3.26, 95% CI: 1.25, 8.49),and no history of change their regimen(AHR=7.1, 95% CI: 2.74, 18.24), were independent predictors of death. Conclusion: more than half of death occurs within 2 years. Prevalent tuberculosis, anemia, wasting, and stunting nutritional status, socioeconomic factors, and baseline opportunistic infection were independent predictors of death. Increasing early screening and managing those predictors are required.

Keywords: human immunodeficiency virus-positive children, anti-retroviral therapy, survival, treatment, Ethiopia

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Authors: Sumit Banerjee, Chandan Kumar Chanda

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The paper presents allocation of active power losses and energy losses to consumers connected to radial distribution networks in a deregulated environment for loads of composite types. A detailed comparison among four algorithms, namely quadratic loss allocation, proportional loss allocation, pro rata loss allocation and exact loss allocation methods are presented. Quadratic and proportional loss allocations are based on identifying the active and reactive components of current in each branch and the losses are allocated to each consumer, pro rata loss allocation method is based on the load demand of each consumer and exact loss allocation method is based on the actual contribution of active power loss by each consumer. The effectiveness of the proposed comparison among four algorithms for composite load is demonstrated through an example.

Keywords: composite type, deregulation, loss allocation, radial distribution networks

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Authors: Hamed Sarbazy, Zohre Gholipour Haftkhani, Ali Safari, Pejman Hosseiniun

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Scientific and industrial progress in the past two decades has resulted in energy distribution systems based on power electronics, as an enabling technology in various industries and building management systems can be considered. Grading and standardization module power electronics systems and its use in a distributed control system, a strategy for overcoming the limitations of using this system. The purpose of this paper is to investigate strategies for scheduling and control structure of standard modules is a power electronic systems. This paper introduces the classical control methods and disadvantages of these methods will be discussed, The hierarchical control as a mechanism for distributed control structure of the classification module explains. The different levels of control and communication between these levels are fully introduced. Also continue to standardize software distribution system control structure is discussed. Finally, as an example, the control structure will be presented in a DC distribution system.

Keywords: application management, hardware management, power electronics, building blocks

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Authors: Bharat Rawat, Shekhar Rajbhandari, Yadav Bhatta, Jay Prakash Jaiswal, Shivaji Bikram Silwal, Rajiv Shrestha, Shova Sunuwar

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Introduction: The honey produced by the bees fed on Rhobdodendron species containing grayanotoxin is known as mad honey. Grayanotoxin is found in honey obtained from the nectar of Rhododendron species growing on the mountains of the Black Sea region of Turkey and also in Japan, Nepal, Brazil, parts of North America, and Europe. Although the incidence of grayanotoxin poisoning is rare, there is concern that the number of cases per year will rise with the increasing demand for organic products. Mad honey intoxication might present with mild symptoms of cardiovascular, gastrointestinal and neurological systems or might also present with a life-threatening form with AV block and cardiovascular collapse. In this article, we describe the summary of five cases, which came to our hospital with mad honey related cardiac complications. Findings: In last one year, five cases presented in the emergency department with sudden onset of Loss of consciousness, dizziness, shortness of breath. They felt difficulty after the consumption of 1-3 teaspoonful of wild honey. The honey was brought from most of the rural parts of Nepal like khotang. Some of them also came with vomiting, dizziness, and loose stool. On examination, most of them had severe bradycardia and low blood pressure. No abnormalities were detected on systemic examinations. In one patient, ECG and cardiac enzymes showed features of the acute coronary syndrome, but his treadmill test done few days later was normal. All patients were managed with inj. Atropine, I/V normal saline, and other supportive measures and discharged in a stable condition within one or two days. Conclusions: Rhododendrons is the national flower of Nepal. The specific species of rhododendron found in Nepal which contains the toxin is not known. Bees feeding on these rhododendrons are known to transfer the grayanotoxin to the honey they produce. Most symptoms are mild and resolve themselves without medical intervention. Signs and symptoms of grayanotoxin poisoning rarely last more than 24 hours and are usually not fatal. Some signs of mad honey poisoning include Bradycardia, Cardiac arrhythmia, Hypotension, Nausea and Vomiting. They respond to close monitoring and appropriate supportive treatment. Normally, patients recover completely with no residual damage to the heart or its conduction system.

Keywords: rhobdodendron, honey, grayanotoxin, bradycardia

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Authors: Naimi Abdelhamid, Othmane Abdelkhalek

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With the current rise in the demand of electrical energy, present-day power systems which are large and complex, will continue to grow in both size and complexity. Flexible AC Transmission System (FACTS) controllers provide new facilities, both in steady state power flow control and dynamic stability control. Thyristor Controlled Series Capacitor (TCSC) is one of FACTS equipment, which is used for power flow control of active power in electric power system and for increase of capacities of transmission lines. In this paper, a Backstepping Power Flow Controller (BPFC) for TCSC in multimachine power system is developed and tested. The simulation results show that the TCSC proposed controller is capable of controlling the transmitted active power and improving the transient stability when compared with conventional PI Power Flow Controller (PIPFC).

Keywords: FACTS, thyristor controlled series capacitor (TCSC), backstepping, BPFC, PIPFC

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Authors: N. Moazami, R. Ranjbar, A. Ashori

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Out of hundreds of microalgal strains reported, only very few of them are capable for production of high content of lipid. Therefore, the key technical challenges include identifying the strains with the highest growth rates and oil contents with adequate composition, which were the main aims of this work. From 147 microalgae screened for high biomass and oil productivity, the Nannochloropsis sp. PTCC 6016, which attained 52% lipid content, was selected for large scale cultivation in Persian Gulf Knowledge Island. Nannochloropsis strain PTCC 6016 belongs to Eustigmatophyceae (Phylum heterokontophyta) isolated from Mangrove forest area of Qheshm Island and Persian Gulf (Iran) in 2008. The strain PTCC 6016 had an average biomass productivity of 2.83 g/L/day and 52% lipid content. The biomass productivity and the oil production potential could be projected to be more than 200 tons biomass and 100000 L oil per hectare per year, in an outdoor algal culture (300 day/year) in the Persian Gulf climate.

Keywords: biofuels, microalgae, Nannochloropsis, raceway open pond, bio-jet

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Authors: Syakirin O. Yong, Nasrudin A. Rahim, Bilal M. Eid, Buray Tankut

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The aim of this paper is to develop an ultra-fast gate driver for Silicon Carbide (SiC) based switching device applications such as AC/DC DC/AC converters. Wide bandgap semiconductors such as SiC switches are growing rapidly nowadays due to their numerous capabilities such as faster switching, higher power density and higher voltage level. Wide band-gap switches can work properly on high frequencies such 50-250 kHz which is very useful for many power electronic applications such as solar inverters. Increasing the frequency minimizes the output filter size and system complexity however, this causes huge spike between MOSFET’s drain and source leg which leads to the failure of MOSFET if the voltage rating is exceeded. This paper investigates and concludes the optimum design for a gate drive board for SiC MOSFET switches without causing spikes and noises.

Keywords: PV system, lithium-ion, charger, constant current, constant voltage, renewable energy

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Authors: Varun Dongre, Stefan Pirker, Stefan Heinrich

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Over the last decades, the numerical modelling of fluidized bed processes has become feasible even for industrial processes. Commonly, continuous two-fluid models are applied to describe large-scale fluidization. In order to allow for coarse grids novel two-fluid models account for unresolved sub-grid heterogeneities. However, computational efforts remain high – in the order of several hours of compute-time for a few seconds of real-time – thus preventing the representation of long-term phenomena such as heating or particle conversion processes. In order to overcome this limitation, data-based recurrence computational fluid dynamics (rCFD) has been put forward in recent years. rCFD can be regarded as a data-based method that relies on the numerical predictions of a conventional short-term simulation. This data is stored in a database and then used by rCFD to efficiently time-extrapolate the flow behavior in high spatial resolution. This study will compare the numerical predictions of rCFD simulations with those of corresponding full CFD reference simulations for lab-scale and pilot-scale fluidized beds. In assessing the predictive capabilities of rCFD simulations, we focus on solid mixing and secondary gas holdup. We observed that predictions made by rCFD simulations are highly sensitive to numerical parameters such as diffusivity associated with face swaps. We achieved a computational speed-up of four orders of magnitude (10,000 time faster than classical TFM simulation) eventually allowing for real-time simulations of fluidized beds. In the next step, we apply the checkerboarding technique by introducing gas tracers subjected to convection and diffusion. We then analyze the concentration profiles by observing mixing, transport of gas tracers, insights about the convective and diffusive pattern of the gas tracers, and further towards heat and mass transfer methods. Finally, we run rCFD simulations and calibrate them with numerical and physical parameters compared with convectional Two-fluid model (full CFD) simulation. As a result, this study gives a clear indication of the applicability, predictive capabilities, and existing limitations of rCFD in the realm of fluidization modelling.

Keywords: multiphase flow, recurrence CFD, two-fluid model, industrial processes

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Authors: Khalid A. Rabaeh, Belal Moftah, Ahmed A. Basfar, Akram A. Almousa

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Polymer gel dosimeters are tissue equivalent martial that fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of absorbed radiation dose. Polymer gel dosimeters can uniquely record the radiation dose distribution in three-dimensions (3D). A novel composition of normoxic polymer gel dosimeters based on radiation-induced polymerization of N-(Hydroxymethyl)acrylamide (NHMA) is introduced in this study for radiotherapy treatment planning. The dosimeters were irradiated by 10 MV photon beam of a medical linear accelerator at a constant dose rate of 600 cGy/min with doses up to 30 Gy. The polymerization degree is directly proportional to absorbed dose received by the polymer gel. UV/Vis spectrophotometer was used to investigate the degree of white color of irradiated NHMA gel which is associated to the degree of polymerization of polymer gel dosimeters. The absorbance increases with absorbed dose for all gel dosimeters in the dose range between 0 and 30 Gy. Dose rate , energy of radiation and the stability of the polymerization after irradiation were investigated. No appreciable effects of these parameters on the performance of the novel gel dosimeters were observed.

Keywords: dosimeter, gel, spectrophotometer, N-(Hydroxymethyl)acrylamide

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Authors: Cui Li, Xu Yuping

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Based on the question of, "Are short video creators who are digital workers controlled by platform rules?" this study discusses the specific ways of platform rules control and the impact on short video creators. Based on the theory of digital labor, this paper adopts the method of in-depth interview and participant observation and chooses 24 producers of short video content of Tiktok to conduct in-depth interview. At the same time, through entering the short video creation field, the author carries on the four-month field investigation, obtains the creation process related data, and analyzes how the short video creator, as the digital labor, is controlled by the platform rule, as well as the creator in this process of compromise and resistance, a more comprehensive presentation of the short video creators of the labor process. It is found that the short video creators are controlled by the platform rules, mainly in the control of traffic rules, and the creators create content, compromise and resist under the guidance of traffic. First, while the platform seems to offer a flexible and autonomous way for creators to monetize, the threshold for participating in the event is actually very high for creators, and the rules for monetizing the event are vague. Under the influence of the flow rule, the creator is faced unstable incomes and high costs. Therefore, creators have to follow the rules of traffic to guide their own creation, began to flow-oriented content production, mainly reflected in the need to keep up-to-date, the pursuit of traffic to ride on the hot spots, in order to flow regardless, set up people "Born for the show", by the label solidified content creation. Secondly, the irregular working hours lead to the extension and overwork of the working hours, which leads to the internal friction of the short video creators at the spiritual level, and finally leads to the Rat Race of video creation. Thirdly, the video creator has completed the internalization and compromise of the platform rules in practice, which promotes the creator to continue to create independently, and forms the intrinsic motive force of the creator. Finally, the rule-controlled short video creators resist and fight in flexible ways, make use of the mechanism and rules of the platform to carry on the second creation, carry on the routine production, purchase the false flow, transfer the creation position to maintain own creation autonomy.

Keywords: short videos, tiktok, production, digital labors

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Authors: N. Chérif, T. Allaoui, M. Benasla, H. Chaib

Abstract:

Industrialization and population growth are the prime factors for which the consumption of electricity is steadily increasing. Thus, to have a balance between production and consumption, it is necessary at first to increase the number of power plants, lines and transformers, which implies an increase in cost and environmental degradation. As a result, it is now important to have mesh networks and working close to the limits of stability in order to meet these new requirements. The transient stability studies involve large disturbances such as short circuits, loss of work or production group. The consequence of these defects can be very serious, and can even lead to the complete collapse of the network. This work focuses on the regulation means that networks can help to keep their stability when submitted to strong disturbances. The magnetic energy storage-based superconductor (SMES) comprises a superconducting coil short-circuited on it self. When such a system is connected to a power grid is able to inject or absorb the active and reactive power. This system can be used to improve the stability of power systems.

Keywords: short-circuit, power oscillations, multiband PSS, power system, SMES, transient stability

Procedia PDF Downloads 449

Authors: Ruth Hegarty, Noel Connaughton

Abstract:

Sustainability reporting has become a priority for many global multinational companies. This is associated with ever-increasing expectations from key stakeholders for companies to be transparent about their strategies, activities and management with regard to sustainability issues. The Global Reporting Initiative (GRI) encourages reporters to only provide information on the issues that are really critical in order to achieve the organisation’s goals for sustainability and manage its impact on environment and society. A key challenge for most reporting organisations is how to identify relevant issues for sustainability reporting and prioritise those material issues in accordance with company and stakeholder needs. A recent study indicates that most of the largest companies listed on the world’s stock exchanges are failing to provide data on key sustainability indicators such as employee turnover, energy, greenhouse gas emissions (GHGs), injury rate, pay equity, waste and water. This paper takes an indepth look at the approaches used by a select number of international sustainability leader corporates to identify key sustainability issues. The research methodology involves performing a detailed analysis of the sustainability report content of up to 50 companies listed on the 2014 Dow Jones Sustainability Indices (DJSI). The most recent sustainability report content found on the GRI Sustainability Disclosure Database is then compared with 91 GRI Specific Standard Disclosures and a small number of GRI Standard Disclosures. Preliminary research indicates significant gaps in the information disclosed in corporate sustainability reports versus the indicator content specified in the GRI Content Index. The following outlines some of the key findings to date: Most companies made a partial disclosure with regard to the Economic indicators of climate change risks and infrastructure investments, but did not focus on the associated negative impacts. The top Environmental indicators disclosed were energy consumption and reductions, GHG emissions, water withdrawals, waste and compliance. The lowest rates of indicator disclosure included biodiversity, water discharge, mitigation of environmental impacts of products and services, transport, environmental investments, screening of new suppliers and supply chain impacts. The top Social indicators disclosed were new employee hires, rates of injury, freedom of association in operations, child labour and forced labour. Lesser disclosure rates were reported for employee training, composition of governance bodies and employees, political contributions, corruption and fines for non-compliance. The reporting on most other Social indicators was found to be poor. In addition, most companies give only a brief explanation on how material issues are defined, identified and ranked. Data on the identification of key stakeholders and the degree and nature of engagement for determining issues and their weightings is also lacking. Generally, little to no data is provided on the algorithms used to score an issue. Research indicates that most companies lack a rigorous and thorough methodology to systematically determine the material issues of sustainability reporting in accordance with company and stakeholder needs.

Keywords: identification of key stakeholders, material issues, sustainability reporting, transparency

Procedia PDF Downloads 303

Authors: Dina M. Abd El-Aty, D. Aman, E. G. Zaki, Heba M. Salem

Abstract:

A friendly environmental source of energy as hydrogen was produced by photo-hydrolysis of hydrogen storage material as sodium borohydride (NaBH4), which is non-toxic and stores a high percentage of hydrogen. The photoreaction was produced under visible light and nano-alumina as a catalyst. In this study, we use more economical and friendly environmental oil as a template to produce a nano-catalyst. The prepared catalyst was characterized by X-Ray diffraction, N2-adsorption-desorption, Fourier Transforms Infrared, Scanning Electron microscope and X-Ray Photoelectron Spectroscopy. Different parameters such as catalyst weight, NaBH4 weight and time of irradiation were studied to obtain a highly efficient photo-hydrolysis reaction. The reaction is pseudo-first order and the hydrogen production rate was determined as 1500 ml min-1 g-1 at the optimum conditions.

Keywords: photo-reaction, nano-alumina, hydrogen production, sodium borohydride, visible light

Procedia PDF Downloads 79

Authors: Masood Ahmad, Ataul Aziz Ikram, Ishtiaq Wahid

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Wireless sensor network (WSN) is the interconnection of mobile wireless nodes with limited energy and memory. These networks can be deployed formany critical applications like military operations, rescue management, fire detection and so on. In flat routing structure, every node plays an equal role of sensor and router. The topology may change very frequently due to the mobile nature of nodes in WSNs. The topology maintenance may produce more overhead messages. To avoid topology maintenance overhead messages, an optimized cluster based mobile wireless sensor network using memetic algorithm is proposed in this paper. The nodes in this network are first divided into clusters. The cluster leaders then transmit data to that base station. The network is validated through extensive simulation study. The results show that the proposed technique has superior results compared to existing techniques.

Keywords: WSN, routing, cluster based, meme, memetic algorithm

Procedia PDF Downloads 477

Authors: Saidur R. Chowdhury, Mamme K. Addai, Ernest K. Yanful

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The research was performed to assess the potential of nickel smelter slag, an industrial waste, as an adsorbent in the removal of metals from aqueous solution. An investigation was carried out for Arsenic (As), Copper (Cu), lead (Pb) and Cadmium (Cd) adsorption from aqueous solution. Smelter slag was obtain from Ni ore at the Vale Inco Ni smelter in Sudbury, Ontario, Canada. The batch experimental studies were conducted to evaluate the removal efficiencies of smelter slag. The slag was characterized by surface analytical techniques. The slag contained different iron oxides and iron silicate bearing compounds. In this study, the effect of pH, contact time, particle size, competition by other ions, slag dose and distribution coefficient were evaluated to measure the optimum adsorption conditions of the slag as an adsorbent for As, Cu, Pb and Cd. The results showed 95-99% removal of As, Cu, Pb, and almost 50-60% removal of Cd, while batch experimental studies were conducted at 5-10 mg/L of initial concentration of metals, 10 g/L of slag doses, 10 hours of contact time and 170 rpm of shaking speed and 25oC condition. The maximum removal of Arsenic (As), Copper (Cu), lead (Pb) was achieved at pH 5 while the maximum removal of Cd was found after pH 7. The column experiment was also conducted to evaluate adsorption depth and service time for metal removal. This study also determined adsorption capacity, adsorption rate and mass transfer rate. The maximum adsorption capacity was found to be 3.84 mg/g for As, 4 mg/g for Pb, and 3.86 mg/g for Cu. The adsorption capacity of nickel slag for the four test metals were in decreasing order of Pb > Cu > As > Cd. Modelling of experimental data with Visual MINTEQ revealed that saturation indices of < 0 were recorded in all cases suggesting that the metals at this pH were under- saturated and thus in their aqueous forms. This confirms the absence of precipitation in the removal of these metals at the pHs. The experimental results also showed that Fe and Ni leaching from the slag during the adsorption process was found to be very minimal, ranging from 0.01 to 0.022 mg/L indicating the potential adsorbent in the treatment industry. The study also revealed that waste product (Ni smelter slag) can be used about five times more before disposal in a landfill or as a stabilization material. It also highlighted the recycled slags as a potential reactive adsorbent in the field of remediation engineering. It also explored the benefits of using renewable waste products for the water treatment industry.

Keywords: adsorption, industrial waste, recycling, slag, treatment

Procedia PDF Downloads 140

Authors: Maedeh Shojaeizadeh, Amirreza Yeganegi

Abstract:

Nowadays many people lose their lives due to cardiovascular diseases. Inappropriate food habits and lack of exercise expedite deposit process of fatty substances on inner surface of blood arteries. This abnormal lump disturbs uniform blood flow and reduces oxygen delivery to active organs. This work presents a numerical simulation of Non-Newtonian blood flow in a stenosis vessel. The vessel is considered as two dimensional channel and plaque area is modelled as a homogenous porous medium. To simulate blood flow reaction around stenosis region, we use C++ code and solve coupled Cauchy, Darcy, governing continuity and energy equations. The analyses results show that viscosity power (n) plays an important role in flow separation and the size of the eddy at the downstream edge of the plaque. It is also observed that with increasing (n) value, temperature discontinuity and likelihood of vessel rupture declined.

Keywords: blood flow, computational fluid dynamic, porosity, power law fluid

Procedia PDF Downloads 452

Authors: Antoni Ivanov, Nikolay Dandanov, Nicole Christoff, Vladimir Poulkov

Abstract:

Spectrum underutilization has made cognitive radio a promising technology both for current and future telecommunications. This is due to the ability to exploit the unused spectrum in the bands dedicated to other wireless communication systems, and thus, increase their occupancy. The essential function, which allows the cognitive radio device to perceive the occupancy of the spectrum, is spectrum sensing. In this paper, the performance of modern adaptations of the four most widely used spectrum sensing techniques namely, energy detection (ED), cyclostationary feature detection (CSFD), matched filter (MF) and eigenvalues-based detection (EBD) is compared. The implementation has been accomplished through the PlutoSDR hardware platform and the GNU Radio software package in very low Signal-to-Noise Ratio (SNR) conditions. The optimal detection performance of the examined methods in a realistic implementation-oriented model is found for the common relevant parameters (number of observed samples, sensing time and required probability of false alarm).

Keywords: cognitive radio, dynamic spectrum access, GNU Radio, spectrum sensing

Procedia PDF Downloads 238