Search results for: heat exchange coefficient

Authors: W. Swiderski

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In the paper introduced the diagnostic technique making possible the research of internal structures in composite materials reinforced fibres using in different applications. The main reason of damages in structures of these materials is the changing distribution of load in constructions in the lifetime. Appearing defect is largely complicated because of the appearance of disturbing of continuity of reinforced fibres, binder cracks and loss of fibres adhesiveness from binders. Defect in composite materials is usually more complicated than in metals. At present, infrared thermography is the most effective method in non-destructive testing composite. One of IR thermography methods used in non-destructive evaluation is vibrothermography. The vibrothermography is not a new non-destructive method, but the new solution in this test is use ultrasonic waves to thermal stimulation of materials. In this paper, both modelling and experimental results which illustrate the advantages and limitations of ultrasonic IR thermography in inspecting composite materials will be presented. The ThermoSon computer program for computing 3D dynamic temperature distribuions in anisotropic layered solids with subsurface defects subject to ulrasonic stimulation was used to optimise heating parameters in the detection of subsurface defects in composite materials. The program allows for the analysis of transient heat conduction and ultrasonic wave propagation phenomena in solids. The experiments at MIAT were fulfilled by means of FLIR SC 7600 IR camera. Ultrasonic stimulation was performed with the frequency from 15 kHz to 30 kHz with maximum power up to 2 kW.

Keywords: composite material, ultrasonic, infrared thermography, non-destructive testing

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Authors: Saeed Yazdani, Sima Mohamadi Amidabadi, Amir Mohamadi Nejsd, Farahnaz Nekoofar

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As a result of uncertainty and doubts about the quantity of agricultural products, greater significance has been attached to risk management in the agricultural sector. Normally, farmers seek to minimize risks, and crop diversity has always been a means to reduce risk. The study at hand seeks to explore the long-term impact of crop diversity on income risk reduction. The timeframe of the study is 1998 to 2018. Initially, the Herfindahl index was used to estimate crop diversity in different periods, and next, the Hodrick-Prescott filter was applied to estimate income risk both in nominal and real terms. Finally, using the vector error correction model (VECM), the long-term impact of crop diversity on two modes of risk for the farmer's income has been estimated. Given the long-term pattern’s results, it is evident that in the long run, crop diversity can reduce income fluctuations in two nominal and real terms. Moreover, results showed that in case the fluctuation shock affects the agricultural income in the short run, to balance out the shock in nominal and real terms, 4 and 3 cycles are needed, respectively. In other words, in each cycle, 25% and 33% of the shock impact can be removed, respectively. Thus, as the results of the error correction coefficient showed, policies need to be put in place to prevent income shocks. In case of a shock, they need to be balanced out in a four-year period, taking inflation into account, and in a three-year period irrespective of the inflation, and reparative policies such as insurance services should be developed.

Keywords: risk, long-term model, Herfindahl index, time series model, vector error correction model

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Authors: Badrane Nohayla, Bamousse Zineb

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Financial crises, exchange rate volatility, fluctuations in commodity prices, increased competitive pressures, and environmental issues are all threats that businesses face. In light of these diverse challenges, proactive, agile, and innovative cash management becomes an indispensable financial shield, allowing companies to thrive despite the adverse conditions of the global environment. In the same spirit, uncertainty, turbulence, volatility, and competitiveness continue to disrupt economic environments, compelling companies to swiftly master innovative breakthroughs that provide added value. In such a context, innovation emerges as a catalytic vector for performance, aiming to reduce costs, strengthen growth, and ultimately ensure the sustainability of Moroccan companies in the national arena. Moreover, innovation in treasury management promises to be one of the key pillars of financial stability, enabling companies to navigate the tumultuous waters of a globalized environment. Therefore, the objective of this study is to better understand the impact of innovative treasury management on cost optimization and, by extension, performance improvement. To elucidate this relationship, we conducted an exploratory qualitative study with 20 large Moroccan companies operating in the Casablanca-Settat region. The results highlight that innovation at the heart of treasury management is a guarantee of sustainability against the risks of failure and stands as a true pivot of the performance of Moroccan companies, an important parameter of their financial balance and a catalytic vector of their growth in the national economic landscape. In this regard, the present study aims to explore the extent to which innovation at the core of the treasury function serves as an indispensable tool for boosting performance while optimising costs in large Moroccan companies.

Keywords: innovative cash management, artificial intelligence, financial performance, risk management, cost savings

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Authors: Li-Wei Wu, Chung-Yu Wang

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Recently, interest has been generated in the search for a new reference framework for value creation that is centered on the co-creation process. Co-creation implies cooperative value creation between service firms and customers and requires the building of experiences as well as the resolution of problems through the combined effort of the parties in the relationship. For customers, values are always co-created through their participation in services. Customers can ultimately determine the value of the service in use. This new approach emphasizes that a customer’s participation in the service process is considered indispensable to value co-creation. An important feature of service in the context of exchange is co-production, which implies that a certain amount of participation is needed from customers to co-produce a service and hence co-create value. Co-production no doubt helps customers better understand and take charge of their own roles in the service process. Thus, this proposal is to encourage co-production, thus facilitating value co-creation of that is reflected in both customers and service firms. Four determinants of co-production are identified in this study, namely, commitment, trust, asset specificity, and decision-making uncertainty. Commitment is an essential dimension that directly results in successful cooperative behaviors. Trust helps establish a relational environment that is fundamental to cross-border cooperation. Asset specificity motivates co-production because this determinant may enhance return on asset investment. Decision-making uncertainty prompts customers to collaborate with service firms in making decisions. In other words, customers adjust their roles and are increasingly engaged in co-production when commitment, trust, asset specificity, and decision-making uncertainty are enhanced. Although studies have examined the preceding effects, to our best knowledge, none has empirically examined the simultaneous effects of all the curvilinear relationships in a single study. When these determinants are excessive, however, customers will not engage in co-production process. In brief, we suggest that the relationships of commitment, trust, asset specificity, and decision-making uncertainty with co-production are curvilinear or are inverse U-shaped. These new forms of curvilinear relationships have not been identified in existing literature on co-production; therefore, they complement extant linear approaches. Most importantly, we aim to consider both the bright and the dark sides of the determinants of co-production.

Keywords: co-production, commitment, trust, asset specificity, decision-making uncertainty

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Authors: Souvik Das, Sandip Bhattacharya, Goutam Mukhopadhyay, Manashi Adhikary

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Wires breakages during cold drawing are a complex phenomenon; wire breakages may be induced by improper wire-rod quality, inappropriate heat-treated microstructure, and/or lubrication breakdown on the wire surface. A comprehensive metallurgical investigation of failed/broken wire samples is therefore essential for understanding the origin of failure. Frequent breakage of wires during drawing is a matter of serious concern to the wire drawers as it erodes their already slim margins through reduced productivity and loss in yield. The present paper highlights the failure investigation of wires of Low Relaxation Prestressed High Carbon grade during cold drawing due to entrapment of hard constituents detached from the roller entry guide during rolling operations. The hardness measurement of this entrapped location indicates 54.9 Rockwell Hardness as against the rest portion 33.4 Rockwell Hardness. The microstructure chemical analysis and X-ray mapping analysis data of the entrapment location confirmed complex chromium carbide originated from D2-steel used in entry guide during the rolling process. Since the harder entrapped phase could not be deformed in the same manner as the parent phase, the failure of the wire rod occurs during hot rolling.

Keywords: LRPC, D2-steel, chromium carbide, roller guide

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Authors: Khaled Suleiman Mohammed Al-Mashrafi

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A compositional plume is a fluid flow in a directional channel of finite width in another fluid of different material composition. The study of the dynamics of compositional plumes plays an essential role in many real-life applications like industrial applications (e.g., iron casting), environmental applications (e.g., salt fingers and sea ice), and geophysical applications (e.g., solidification at the inner core boundary (ICB) of the Earth, and mantle plumes). The dynamics of compositional plumes have been investigated experimentally and theoretically. The experimental works observed that the plume flow seems to be stable, although some experiments showed that it can be unstable. At the same time, the theoretical investigations showed that the plume flow is unstable. This is found to be true even if the plume is subject to rotation or/and in the presence of a magnetic field and even if another plume of different composition is also present. It is noticeable that all the theoretical studies on the dynamics of compositional plumes are conducted in unbounded domains. The present work is to investigate theoretically the influence of vertical walls (boundaries) on the dynamics of compositional plumes in the absence/presence of a rotation field. The mathematical model of the dynamics of compositional plumes used the equations of continuity, motion, heat, concentration of light material, and state. It is found that the presence of boundaries has a strong influence on the basic state solution as well as the stability of the plume, particularly when the plume is close to the boundary, but the compositional plume remains unstable.

Keywords: compositional plumes, stability, bounded domain, vertical boundaries

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Authors: Abdul-Nasser El-Kassar, Walid Elgammal, Hisham Jawhar

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This paper studies the determinants of the dividends payout ratio. The factors affecting the dividends payout ratio are to be identified. The study focuses only on the cement and construction industry within the MENA region in an attempt to isolate any incoherent behavior. The factors under consideration are: sales growth, ROE, ROA, ROS, debt to equity ratio, firm size, and free cash flow. Data were collected from official stock exchange markets in addition to annual reports. The study considered all firms that paid dividend in each of the three consecutive years starting from 2010 till 2012. Out of the 123 listed firms that work in cement and construction industry in MENA region, only 19 paid dividends in the three consecutive years 2010-12. Our sample consists of the 19 firms (57 observations) which are selected according to purposive sampling. Moreover, the study uses the homogeneous subcategory within the purposive sampling since only similar firms in the construction industry had been examined. The outcome of the study provides a vital insight into the determinants of dividends payout ratio of companies in MENA region. The results showed that the dividend payout ratio has a strong and positive relationship with return on assets and strong but negative relationship with return on equity. On the other hand, the results detected weak relationships between dividend payout ratio and sale growth, debt to equity ratio, firm size, and free cash flow. The study suggests that board of directors tend to compensate shareholders and minimize the agency cost by distributing a high portion of profits in form of dividends whenever return on equity decreases. Also, when the performance of the firm improves, and hence return on assets increases, boards of directors are more generous in distributing profits.

Keywords: dividends payout ratio, profitability firm size, free cashflow, debt to equity ratio

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Authors: Sarisha Devnath, Oluwatosin A. Ijabadeniyi

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In recent years milk contamination has become a major problem in households; due to the likely occurrence of bacteria, even after the milk has been processed. One such genus of bacteria causing unwanted growth is Bacillus. This research project looks at the presence of spore formers in processed milk from household refrigerators and the effect of pasteurization and high temperature on Bacillus spores activation. 24 samples each of UHT milk and pasteurised milk from 24 households were sampled for the presence of spore formers. While anaerobic spore formers were not found in any of the samples, the average aerobic spore formers in UHT milk and pasteurized milk however were 5.77 cfu/ml and 5.88 cfu/ml respectively. After sequencing, it was detected that the mixed culture contained Bacillus cereus, for both pasteurised and UHT milk samples. For the activation study, raw milk samples were collected and subjected to four different temperatures; 65˚C, 72˚C, 80˚C, 100˚C respectively. Samples were stored for 7 days at 5˚C and 10˚C and analysed daily. The average aerobic spore formers in raw milk for samples stored at 5˚C range between 4.67-6.00 cfu/ml while it ranges between 4.84-6.00 cfu/ml at 10˚C, signifying that the high temperatures could have resulted in germination of dominant spores. Statistical analysis conducted on these results indicated a significant difference between the numbers of colonies present at the different treatment temperatures the bacterium was exposed to. This work showed that household milk may constitute public health risk furthermore; pasteurization and higher temperatures may not be effective to remove aerobic spore formers because of Bacillus spores activation.

Keywords: sporeformers, bacillus, spores, activation, milk

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Authors: Anees Tahir

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Margin financing plays a significant role in Pakistan's stock market (PSX), offering investors the opportunity to maximize profits by borrowing funds from financiers to purchase marginable stocks. However, this financial practice raises several Shariah-related concerns. The study follows legal doctrinal research methodology. It explains and analyzes the law of margin financing prevailing in PSX and compares it with the principles of Shariah. It also examines and investigates the practices of margin financing from the perspective of Shariah. As part of the study, the researcher has conducted structured interviews with the Shariah advisors of the finance industry, academicians, market practitioners, and regulators. Thus, the study analyzes the findings of interviews. This article explores the legal framework and practice of margin financing in Pakistan from a Shariah perspective. The article investigates various issues relating to margin financing, including the fundamental concern of interest-based lending, which contravenes Islamic principles. It also highlights the problematic subject matter of margin financing, often involving non-Shariah compliant securities. Additionally, the article addresses the restriction on proprietary rights and the problematic element of speculation associated with margin financing. To provide a Shariah-compliant alternative, the Securities and Exchange Commission of Pakistan (SECP) introduced Murabahah Shares Financing (MSF) in 2019. However, the focus of the market is still on conventional margin financing. In the opinion of the researcher, the effective implementation of MSF is imperative because in the absence of such an alternative, the faith sensitive investor will remain deprived of a level playing field, and he is unable to get required financing opportunities through a halal and Shariah-compliant manner. This article argues that margin financing in its current form is incompatible with Shariah principles and should be discontinued. It is recommended that the SECP should gradually phase out the use of margin financing and increase reliance on MSF to provide faith-sensitive and committed investors with Shariah-compliant financing options.

Keywords: margin financing, marginable stocks, faith sensitive investor, Murabahah shares financing

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Authors: Vahid Nourani, Atefeh Ashrafi

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Prediction of treated wastewater quality is a matter of growing importance in water treatment procedure. In this way artificial neural network (ANN), as a robust data-driven approach, has been widely used for forecasting the effluent quality of wastewater treatment. However, developing ANN model based on appropriate input variables is a major concern due to the numerous parameters which are collected from treatment process and the number of them are increasing in the light of electronic sensors development. Various studies have been conducted, using different clustering methods, in order to classify most related and effective input variables. This issue has been overlooked in the selecting dominant input variables among wastewater treatment parameters which could effectively lead to more accurate prediction of water quality. In the presented study two ANN models were developed with the aim of forecasting effluent quality of Tabriz city’s wastewater treatment plant. Biochemical oxygen demand (BOD) was utilized to determine water quality as a target parameter. Model A used Principal Component Analysis (PCA) for input selection as a linear variance-based clustering method. Model B used those variables identified by the mutual information (MI) measure. Therefore, the optimal ANN structure when the result of model B compared with model A showed up to 15% percent increment in Determination Coefficient (DC). Thus, this study highlights the advantage of PCA method in selecting dominant input variables for ANN modeling of wastewater plant efficiency performance.

Keywords: Artificial Neural Networks, biochemical oxygen demand, principal component analysis, mutual information, Tabriz wastewater treatment plant, wastewater treatment plant

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Authors: My Linh Hoang, Van Dung Hoang

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Environmental, Social, and Governance (ESG) factors have become a focus for companies globally, as businesses are now focusing on long-term sustainable goals rather than only operating for the goals of profit maximization. According to recent research, in several countries, companies have shown positive results in their financial performance by improving their ESG performance. The construction industry is one of the most crucial components of social and economic development; as a result, considerations for ESG factors are becoming more and more essential for companies in this sector. In Vietnam, the construction industry has been growing rapidly in recent years; however, it has yet to be discussed and studied extensively in Vietnam how ESG factors create impacts on corporate financial performance in general and construction corporations’ financial performance in particular. This research aims to examine the relationship between ESG factors and financial indicators in construction companies from 2011 to 2021 through panel data analysis of 75 listed construction companies in Vietnam and to provide insights into how these companies can better integrate ESG considerations into their operations to enhance their financial performance. The data was analyzed through 3 main methods: descriptive statistics, correlation coefficient analysis applied to all dependent, explanatory and control variables, and panel data analysis method. In panel data analysis, the study uses the fixed effects model (FEM) and random effects model (REM). The Hausman test will be used to select which model is suitable to be used. The findings indicate that maintaining a strong commitment to ESG principles can have a positive impact on financial performance. Finally, FGLS estimation will be performed when the problem of autocorrelation and variable variance appears in the model. This is significant for all parties involved, including investors, company managers, decision-makers, and industry regulators.

Keywords: ESG, financial performance, construction company, Vietnam

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Authors: Gezahegn Gizaw

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The FDRE Tourism Training Institute organizes forums for debates, best practices exchange and focus group discussions to forge a sustainable and growing tourism sector while minimizing negative impacts on the environment, communities, and cultures. This study aimed at applying empirical research method to identify and quantify relative importance of success factors and individual engagement indicators that were identified in these forums. Response to the 12-question survey was collected from a total of 437 respondents in academic training institutes (212), business executive and employee (204) and non-academic government offices (21). Overall, capacity building was perceived as the most important driver of success for stakeholder engagement. Business executive and employee category rated capacity building as the most important driver of success (53%), followed by decision-making process (27%) and community participation (20%). Among educators and students, both capacity building and decision-making process were perceived as the most important factors (40% of respondents), whereas community participation was perceived as the most important success factor only by 20% of respondents. Individual engagement score in capacity building, decision-making process and community participation showed highest variability by educational level of participants (variance of 3.4% - 5.2%, p<0.001). Individual engagement score in capacity building was highly correlated to perceived benefit of training on improved efficiency, job security, higher customer satisfaction and self-esteem. On the other hand, individual engagement score in decision making process was highly correlated to its perceived benefit on lowering business costs, improving ability to meet the needs of a target market, job security, self-esteem and more teamwork. The study provides a set of recommendations that help educators, business executives and policy makers to maximize the individual and synergetic effect of training, decision making process on sustainability and growth of the tourism sector in Ethiopia.

Keywords: engagement score, driver of success, capacity building, tourism

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Authors: Hossam E. Emam

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The functional textiles development history in the military field could be ascribed as a uniquely interesting research topic. Soldiers are like a high-performance athletes, where monitoring their physical and physiological capabilities is a vital requirement. Functional clothes represent a “second skin” that has a close, “intimate” relationship with the human body. For the application of textiles in military purposes, which is normally required in difficult weather and environmental conditions, several functions are required. The requirements for designing functional military textiles for soldier's protection can be categorized into three categories; i) battle field (protection from chemical warfare agents, flames, and thermal radiation), ii) environmental (water proof, air permeable, UV-protection, antibacterial), iii) physiological (minimize heat stress, low weight, insulative, durability). All of these requirements are important, but the means to fulfill these requirements are not simple and straight forward. Additionally, the combination of more than one function is reported to be very expensive and requires many complicated steps, and the final product is found to be low durability. Not only do all of these requirements are overlapping, but they are also contradicting each other at various levels. Thus, we plan to produce multi-functional textiles (e.g., anti-microbial, UV-protection, fire retardant, photoluminescent) to be applied in military clothes. The current project aims to use quite a simple and applicable technique through the modification of textiles with different coordination polymers and functionalized coordination polymers.

Keywords: functional textiles, military clothes, coordination polymers, antimicrobial, fire retardant, photolumenscent

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Authors: Maciej Jedrzejczyk, Karolina Marzantowicz

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Traditional utility value chain is being transformed during last few years into unbundled markets. Increased distributed generation of energy is one of considerable challenges faced by Smart Grid networks. New sources of energy introduce volatile demand response which has a considerable impact on traditional middlemen in E&U market. The purpose of this research is to search for ways to allow near-real-time electricity markets to transact with surplus energy based on accurate time synchronous measurements. A proposed framework evaluates the use of secure peer-2-peer (P2P) communication and distributed transaction ledgers to provide flat hierarchy, and allow real-time insights into present and forecasted grid operations, as well as state and health of the network. An objective is to achieve dynamic grid operations with more efficient resource usage, higher security of supply and longer grid infrastructure life cycle. Methods used for this study are based on comparative analysis of different distributed ledger technologies in terms of scalability, transaction performance, pluggability with external data sources, data transparency, privacy, end-to-end security and adaptability to various market topologies. An intended output of this research is a design of a framework for safer, more efficient and scalable Smart Grid network which is bridging a gap between traditional components of the energy network and individual energy producers. Results of this study are ready for detailed measurement testing, a likely follow-up in separate studies. New platforms for Smart Grid achieving measurable efficiencies will allow for development of new types of Grid KPI, multi-smart grid branches, markets, and businesses.

Keywords: autonomous agents, Distributed computing, distributed ledger technologies, large scale systems, micro grids, peer-to-peer networks, Self-organization, self-stabilization, smart grids

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Authors: A. Abbas, X. Tridon, J. Michelon

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In the electronic or in the photovoltaic industries, components are made from wafers which are stacks of thin film layers of a few nanometers to serval micrometers thickness. Early evaluation of the bounding quality between different layers of a wafer is one of the challenges of these industries to avoid dysfunction of their final products. Traditional pump-probe experiments, which have been developed in the 70’s, give a partial solution to this problematic but with a non-negligible drawback. In fact, on one hand, these setups can generate and detect ultra-high ultrasounds frequencies which can be used to evaluate the adhesion quality of wafer layers. But, on the other hand, because of the quiet long acquisition time they need to perform one measurement, these setups remain shut in punctual measurement to evaluate global sample quality. This last point can lead to bad interpretation of the sample quality parameters, especially in the case of inhomogeneous samples. Asynchronous Optical Sampling (ASOPS) systems can perform sample characterization with picosecond acoustics up to 106 times faster than traditional pump-probe setups. This last point allows picosecond ultrasonic to unlock the acoustic imaging field at the nanometric scale to detect inhomogeneities regarding sample mechanical properties. This fact will be illustrated by presenting an image of the measured acoustical reflection coefficients obtained by mapping, with an ASOPS setup, a 255nm thin-film tungsten layer deposited on a silicone substrate. Interpretation of the coefficient reflection in terms of bounding quality adhesion will also be exposed. Origin of zones which exhibit good and bad quality bounding will be discussed.

Keywords: adhesion, picosecond ultrasonics, pump-probe, thin film

Procedia PDF Downloads 156

Authors: Tukur Daiyabu Abdulkadir, Wan Ishak Wan Ismail, Muhammad Saufi Mohd Kassim

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Seed singulation and accuracy in seed spacing are the major challenges associated with the adoption of mechanical seeder for system of rice intensification. In this research the metering system of a pneumatic planter was modified and automated for increase precision to meet the demand of system of rice intensification SRI. The chain and sprocket mechanism of a conventional vacuum planter were now replaced with an electro mechanical system made up of a set of servo motors, limit switch, micro controller and a wheel divided into 10 equal angles. The circumference of the planter wheel was determined based on which seed spacing was computed and mapped to the angles of the metering wheel. A program was then written and uploaded to arduino micro controller and it automatically turns the seed plates for seeding upon covering the required distance. The servo motor was calibrated with the aid of labVIEW. The machine was then calibrated using a grease belt and varying the servo rpm through voltage variation between 37 rpm to 47 rpm until an optimum value of 40 rpm was obtained with a forward speed of 5 kilometers per hour. A pressure of 1.5 kpa was found to be optimum under which no skip or double was recorded. Precision in spacing (coefficient of variation), miss index, multiple index, doubles and skips were investigated. No skip or double was recorded both at laboratory and field levels. The operational parameters under consideration were both evaluated at laboratory and field. Even though there was little variation between the laboratory and field values of precision in spacing, multiple index and miss index, the different is not significant as both laboratory and field values fall within the acceptable range.

Keywords: automation, calibration, pneumatic seed planter, system of rice intensification

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Authors: Salah Hassab Elnaby, Omnia Hamdy, Aziza Ahmed Hassan, Salwa Abdelkawi, Ibrahim Abdelhalim

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Laser corneal reshaping has been proposed as a successful treatment of many refraction disorders. However, some physical and chemical demonstrations of the laser effect upon interaction with the corneal tissue are still not fully explained. Therefore, different computational and mathematical models have been implemented to predict the depth of the ablated channel and calculate the ablation threshold and the local temperature rise. In the current paper, we present a modified model that aims to answer some of the open questions about the ablation threshold, the ablation rate, and the physical and chemical mechanisms of that action. The proposed model consists of three parts. The first part deals with possible photochemical reactions between the incident photons and various components of the cornea (collagen, water, etc.). Such photochemical reactions may end by photo-ablation or just the electronic excitation of molecules. Then a chemical reaction is responsible for the ablation threshold. Finally, another chemical reaction produces fragments that can be cleared out. The model takes into account all processes at the same time with different probabilities. Moreover, the effect of applying different laser wavelengths that have been studied before, namely the common excimer laser (193-nm) and the solid state lasers (213-nm & 266-nm), has been investigated. Despite the success and ubiquity of the ArF laser, the presented results reveal that a carefully designed 213-nm laser gives the same results with lower operational drawbacks. Moreover, the use of mode locked laser could also decrease the risk of heat generation and diffusion.

Keywords: UV lasers, mathematical model, corneal ablation, photochemical ablation

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Authors: Daniel José de Oliveira Ferreira, Juan Harold Sosa-Arnao, Bruno Cássio Moreira, Leonardo Paes Rangel, Song Won Park

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The comprehensive CFD models have been used to represent and study the heterogeneous combustion of biomass. In the present work, the operation of a global flue gas circuit in the sugar-cane bagasse combustion, from wind boxes below primary air grate supply, passing by bagasse insertion in swirl burners and boiler furnace, to boiler bank outlet is simulated. It uses five different meshes representing each part of this system located in sequence: wind boxes and grate, boiler furnace, swirl burners, super heaters and boiler bank. The model considers turbulence using standard k-ε, combustion using EDM, radiation heat transfer using DTM with 16 ray directions and bagasse particle tracking represented by Schiller-Naumann model. The results showed good agreement with expected behavior found in literature and equipment design. The more detailed results view in separated parts of flue gas system allows to observe some flow behaviors that cannot be represented by usual simplifications like bagasse supply under homogeneous axial and rotational vectors and others that can be represented using new considerations like the representation of 26 thousand grate orifices by 144 rectangular inlets.

Keywords: comprehensive CFD model, sugar-cane bagasse combustion, sugar-cane bagasse grate boiler, axial

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Authors: Haithem Elderrat, Huw Davies, Emmanuel Brousseau

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Elastomeric polymer foam has been used widely in the automotive industry, especially for isolating unwanted vibrations. Such material is able to absorb unwanted vibration due to its combination of elastic and viscous properties. However, the ‘creep effect’, poor stress distribution and susceptibility to high temperatures are the main disadvantages of such a system. In this study, improvements in the performance of elastomeric foam as a vibration isolator were investigated using the concept of Foam Filled Fluid (FFFluid). In FFFluid devices, the foam takes the form of capsule shapes, and is mixed with viscous fluid, while the mixture is contained in a closed vessel. When the FFFluid isolator is affected by vibrations, energy is absorbed, due to the elastic strain of the foam. As the foam is compressed, there is also movement of the fluid, which contributes to further energy absorption as the fluid shears. Also, and dependent on the design adopted, the packaging could also attenuate vibration through energy absorption via friction and/or elastic strain. The present study focuses on the advantages of the FFFluid concept over the dry polymeric foam in the role of vibration isolation. This comparative study between the performance of dry foam and the FFFluid was made according to experimental procedures. The paper concludes by evaluating the performance of the FFFluid isolator in the suspension system of a light vehicle. One outcome of this research is that the FFFluid may preferable over elastomer isolators in certain applications, as it enables a reduction in the effects of high temperatures and of ‘creep effects’, thereby increasing the reliability and load distribution. The stiffness coefficient of the system has increased about 60% by using an FFFluid sample. The technology represented by the FFFluid is therefore considered by this research suitable for application in the suspension system of a light vehicle.

Keywords: FFFluid, dry foam, anti-vibration devices, elastomeric polymer foam

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Authors: N. Nalini, Bhanu Prakash Gopularam

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The term data security refers to the degree of resistance or protection given to information from unintended or unauthorized access. The core principles of information security are the confidentiality, integrity and availability, also referred as CIA triad. Cloud computing services are classified as SaaS, IaaS and PaaS services. With cloud adoption the confidential enterprise data are moved from organization premises to untrusted public network and due to this the attack surface has increased manifold. Several cloud computing platforms like OpenStack, Eucalyptus, Amazon EC2 offer users to build and configure public, hybrid and private clouds. While the traditional encryption based on PKI infrastructure still works in cloud scenario, the management of public-private keys and trust certificates is difficult. The Identity based Public Key Cryptography (also referred as ID-PKC) overcomes this problem by using publicly identifiable information for generating the keys and works well with decentralized systems. The users can exchange information securely without having to manage any trust information. Another advantage is that access control (role based access control policy) information can be embedded into data unlike in PKI where it is handled by separate component or system. In OpenStack cloud platform the keystone service acts as identity service for authentication and authorization and has support for public key infrastructure for auto services. In this paper, we explain OpenStack security architecture and evaluate the PKI infrastructure piece for data confidentiality. We provide method to integrate ID-PKC schemes for securing data while in transit and stored and explain the key measures for safe guarding data against security attacks. The proposed approach uses JPBC crypto library for key-pair generation based on IEEE P1636.3 standard and secure communication to other cloud services.

Keywords: data confidentiality, identity based cryptography, secure communication, open stack key stone, token scoping

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Authors: A. Azizi, S. Laidoudi, G. Schmerber, A. Dinia

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Cuprous oxide (Cu2O) is a well-known oxide semiconductor with a band gap of 2.1 eV and a natural p-type conductivity, which is an attractive material for device applications because of its abundant availability, non toxicity, and low production cost. It has a higher absorption coefficient in the visible region and the minority carrier diffusion length is also suitable for use as a solar cell absorber layer and it has been explored in junction with n type ZnO for photovoltaic applications. Cu2O nanostructures have been made by a variety of techniques; the electrodeposition method has emerged as one of the most promising processing routes as it is particularly provides advantages such as a low-cost, low temperature and a high level of purity in the products. In this work, Cu2O nanostructures prepared by electrodeposition from aqueous cupric sulfate solution with citric acid at 65°C onto a fluorine doped tin oxide (FTO) coated glass substrates were investigated. The effects of deposition potential on the electrochemical, surface morphology, structural and optical properties of Cu2O thin films were investigated. During cyclic voltammetry experiences, the potential interval where the electrodeposition of Cu2O is carried out was established. The Mott–Schottky (M-S) plot demonstrates that all the films are p-type semiconductors, the flat-band potential and the acceptor density for the Cu2O thin films are determined. AFM images reveal that the applied potential has a very significant influence on the surface morphology and size of the crystallites of thin Cu2O. The XRD measurements indicated that all the obtained films display a Cu2O cubic structure with a strong preferential orientation of the (111) direction. The optical transmission spectra in the UV-Visible domains revealed the highest transmission (75 %), and their calculated gap values increased from 1.93 to 2.24 eV, with increasing potentials.

Keywords: Cu2O, electrodeposition, Mott–Schottky plot, nanostructure, optical properties, XRD

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Authors: Dalia Bhattacharjee

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Motherhood as an institution is considered as sacred. Reproduction and motherhood have always been a concern of the private space of home. However, with the emergence of technologies like the Assisted Reproductive Technologies (ARTs), this intimate area has moved into the public. A woman can now become a mother with artificial insemination done by expert medical professionals in a hospital. With this development, the meanings of motherhood and childrearing have altered. Mothers have been divided into ‘ovarian mothers’ (those who provide the eggs), ‘uterine mothers’ (those who carry out the pregnancy and give birth), and ‘social mothers’ (those who raise the child). Thus, the ART business deconstructs motherhood by defining who the biological mother is and who the social mother is and who – despite contributing parts or processes of her body to the life of the child is not a mother, but merely the donor of a product, be it the egg or the womb, which is owned by those who are favoured by the contract. The industry of commercial surrogacy in India has been estimated to be of $2.3 billion as of 2012. There are many women who work as surrogate mothers in this industry for the exchange of money. It runs like a full-fledged business guided by a highly profit oriented capitalist market. The reproductive labourers are identified as mere womb renters or victims and not as active agents in such arrangements. Such a discourse undercuts the agency exercised by the women. The present study is an ethnography into the commercial surrogacy industry in India. This journey furthers the understanding of the dilemmas faced by the reproductive labourers. The paper emphasizes on the experiences of reproduction and motherhood outside the private space of the home in the commercial surrogacy industry in India, and, argues that this multiplicity of experiences need much focus and attention, where, the consumer becomes ‘the’ citizen and the women workers continue to be victims. The study draws on the narratives of the reproductive labourers, who remain at the center, and yet, at the periphery of such arrangements. This feminist ethnography is informed by the feminist standpoint theory to account for and analyse these varied experiences which further the understanding of the dilemmas faced by the reproductive labourers.

Keywords: commercial surrogacy, ethnography, motherhood, standpoint theory

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Authors: John Eric C. Bargas, Maria Cecilia M. Marcos

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One of the most common ground improvement techniques is Deep Soil Mixing (DSM). As the technique progresses, there is still lack in the development when it comes to depth control. This was the issue experienced during the installation of DSM in one of the National projects in the Philippines. This study assesses the feasibility of using equipment drilling parameters such as hydraulic pressure, drilling speed and rotational speed in determining the Standard Penetration Test N-value of a specific soil. Hydraulic pressure and drilling speed with a constant rotational speed of 30 rpm have a positive correlation with SPT N-value for cohesive soil and sand. A linear trend was observed for cohesive soil. The correlation of SPT N-value and hydraulic pressure yielded a R²=0.5377 while the correlation of SPT N-value and drilling speed has a R²=0.6355. While the best fitted model for sand is polynomial trend. The correlation of SPT N-value and hydraulic pressure yielded a R²=0.7088 while the correlation of SPT N-value and drilling speed has a R²=0.4354. The low correlation may be attributed to the behavior of sand when the auger penetrates. Sand tends to follow the rotation of the auger rather than resisting which was observed for very loose to medium dense sand. Specific Energy and the product of hydraulic pressure and drilling speed yielded same R² with a positive correlation. Linear trend was observed for cohesive soil while polynomial trend for sand. Cohesive soil yielded a R²=0.7320 which has a strong relationship. Sand also yielded a strong relationship having a coefficient of determination, R²=0.7203. It is feasible to use hydraulic pressure and drilling speed to estimate the SPT N-value of the soil. Also, the product of hydraulic pressure and drilling speed can be a substitute to specific energy when estimating the SPT N-value of a soil. However, additional considerations are necessary to account for other influencing factors like ground water and physical and mechanical properties of soil.

Keywords: ground improvement, equipment drilling parameters, standard penetration test, deep soil mixing

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Authors: Reza Hosseinpourpia, Stergios Adamopoulos, Carsten Mai

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Medium density fiberboard (MDF) is a common category of wood-based panels that are widely used in the furniture industry. Fine lignocellulosic fibres are combined with a synthetic resin, mostly urea formaldehyde (UF), and joined together under heat and pressure to form panels. Like solid wood, MDF is a hygroscopic material; therefore, its moisture content depends on the surrounding relative humidity and temperature. In addition, UF is a hydrophilic resin and susceptible to hydrolysis under certain conditions of elevated temperatures and humidity, which cause dimensional instability of the panels. The latter directly affect the performance of final products such as furniture, when they are used in situations of high relative humidity. Existing water-repellent formulations, such as paraffin, present limitations related to their non-renewable nature, cost and highest allowed added amount. Therefore, the aim of the present study was to test the suitability of renewable water repellents as alternative chemicals for enhancing the dimensional stability of MDF panels. A small amount of tall oil based formulations were used as water-repellent agents in the manufacturing of laboratory scale MDF. The effects on dimensional stability, internal bond strength and formaldehyde release of MDF were tested. The results indicated a good potential of tall oil as a bio-based substance of water repellent formulations for improving the dimensional stability of MDF.

Keywords: dimensional stability, medium density fiberboard, tall oil, urea formaldehyde

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Authors: Sun fang, Zhang Wenxin

Abstract:

This paper establishes an evaluation index system for spatio-temporal patterns of urbanization, with the county as research unit. We use the Entropy Weight method, coefficient variance, the Theil index and ESDA-GIS to analyze spatial patterns and evolutionary characteristics of New-Type Urbanization in the Central Plains Economic Region (CPER) between 2000 and 2011. Results show that economic benefit, non-agricultural employment level and level of market development are the most important factors influencing the level of New-Type Urbanization in the CPER; overall regional differences in New-Type Urbanization have declined while spatial correlations have increased from 2000 to 2011. The overall spatial pattern has changed little, however; differences between the western and eastern areas of the CPER are clear, and the pattern of a strong west and weak east did not change significantly over the study period. Areas with high levels of New-Type Urbanization were mostly distributed along the Beijing-Guangzhou and LongHai Railways on both sides, a new influx of urbanization was tightly clustered around ZhengZhou in the Central Henan Urban Agglomeration, but this trend was found to be weakening slightly. The level of New-Type Urbanization in municipal districts was found to be much higher than it was in the county generally. Provincial borders experienced a lower rate of growth and a lower level of New-Type Urbanization than did any other areas, consistently forming clusters of cold spots and sub-cold spots. The analysis confirms that historical development, location, and diffusion effects of urban agglomeration are the main drivers of changes in New-Type Urbanization patterns in CPER.

Keywords: new-type urbanization, spatial pattern, central plains economic region, spatial evolution

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Authors: Bal Chandra Yadav, Rakesh K. Sonker, Anjali Sharma, Punit Tyagi, Vinay Gupta, Monika Tomar

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In the present study, ZnO doped SnO2 thin films of various compositions were deposited on the surface of a corning substrate by dropping the two sols containing the precursors for composite (ZSO) with subsequent heat treatment. The sensor materials used for selective detection of nitrogen dioxide (NO2) were designed from the correlation between the sensor composition and gas response. The available NO2 sensors are operative at very high temperature (150-800 °C) with low sensing response (2-100) even in higher concentrations. Efforts are continuing towards the development of NO2 gas sensor aiming with an enhanced response along with a reduction in operating temperature by incorporating some catalysts or dopants. Thus in this work, a novel sensor structure based on ZSO nanocomposite has been fabricated using chemical route for the detection of NO2 gas. The structural, surface morphological and optical properties of prepared films have been studied by using X-ray diffraction (XRD), Atomic force microscopy (AFM), Transmission electron microscope (TEM) and UV-visible spectroscopy respectively. The effect of thickness variation from 230 nm to 644 nm of ZSO composite thin film has been studied and the ZSO thin film of thickness ~ 460 nm was found to exhibit the maximum gas sensing response ~ 2.1×103 towards 20 ppm NO2 gas at an operating temperature of 90 °C. The average response and recovery times of the sensor were observed to be 3.51 and 6.91 min respectively. Selectivity of the sensor was checked with the cross-exposure of vapour CO, acetone, IPA, CH4, NH3 and CO2 gases. It was found that besides the higher sensing response towards NO2 gas, the prepared ZSO thin film was also highly selective towards NO2 gas.

Keywords: ZSO nanocomposite thin film, ZnO tetrapod structure, NO2 gas sensor, sol-gel method

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Authors: Su Ying-Ming

Abstract:

High density of high rise buildings in urban areas lead to a deteriorative Urban Heat Island Effect, gradually. This study focuses on discussing the relationship between urban layout and ventilation comfort in street canyons. This study takes Songjiang Nanjing Rd. area of Taipei, Taiwan as an example to evaluate the wind environment comfort index by field measurement and Computational Fluid Dynamics (CFD) to improve both the quality and quantity of the environment. In this study, different factors including street blocks size, the width of buildings, street width ratio and the direction of the wind were used to discuss the potential of ventilation. The environmental wind field was measured by the environmental testing equipment, Testo 480. Evaluation of blocks sizes, the width of buildings, street width ratio and the direction of the wind was made under the condition of constant floor area with the help of Stimulation CFD to adjust research methods for optimizing regional wind environment. The results of this study showed the width of buildings influences the efficiency of outdoor ventilation; improvement of the efficiency of ventilation with large street width was also shown. The study found that Block width and H/D value and PR value has a close relationship. Furthermore, this study showed a significant relationship between the alteration of street block geometry and outdoor comfortableness.

Keywords: urban ventilation path, ventilation efficiency indices, CFD, building layout

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Authors: Farnaz Amidi Fazli

Abstract:

After long period of human experience about food processing from raw eating to canning of food in the last century now it is time to use novel technologies which are sometimes completely different from common technologies. It is possible to decontaminate food without using heat or the foods are stored without using cold chain. Pulsed electric field (PEF) processing is a non-thermal method of food preservation that uses short bursts of electricity, PEF can be used for processing liquid and semi-liquid food products. PEF processing offers high quality fresh-like liquid foods with excellent flavor, nutritional value, and shelf-life. High pressure processing (HPP) technology has the potential to fulfill both consumer and scientific requirements. The use of HPP for over 50 years has found applications in non-food industries. For food applications, ‘high pressure’ can be generally considered to be up to 600 MPa for most food products. After years, freezing has its high potential to food preservation due to new and quick freezing methods. Foods which are prepared by this technology have more acceptability and high quality comparing with old fashion slow freezing. Thus, quick freezing has further been adopted as a widespread commercial method for long-term preservation of perishable foods which improved both the health and convenience of everyone in the industrialised countries. Above parameters are achieved by Fluidised-bed freezing systems, freezing by immersion and Hydrofluidisation on the other hand new thawing methods like high-pressure, microwave, ohmic, and acoustic thawing have a key role in quality and adaptability of final product.

Keywords: quick freezing, thawing, high pressure, pulse electric, hydrofluidisation

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Authors: Anne Jane M. Hallasgo

Abstract:

This study assessed the level of job satisfaction and organizational commitment among job order personnel at the Overseas Workers Welfare Administration (OWWA) Regional Welfare Office Caraga. The primary objective of the study was to determine a correlation between the employees’ level of organizational commitment, job satisfaction, and their work performance. A carefully selected sample of twenty-five job orders from the OWWA Regional Welfare Office Caraga participated in the study. These individuals were chosen to represent the organization’s job order workforce. For accuracy and dependability, various types of statistical methods and instruments were employed, including advanced statistical tests like the independent sample T-test, one-way analysis of variance (ANOVA), and Spearman's rank correlation coefficient, as well as descriptive statistics like mean, frequency, and percentage. The study found an acceptable level of job satisfaction regarding work performance. It revealed a significant relationship between affective commitment and job satisfaction concerning leadership and coworkers. A correlation was observed between normative commitment and work performance. The findings suggest that organizations emphasizing positive leadership, fostering supportive coworker relationships, aligning with employee values, and promoting a culture of commitment are likely to enhance both affective and normative commitment, thereby improving overall employee satisfaction. The study recommends designing and implementing a holistic employee well-being program that addresses physical, mental, and emotional health contributing to increased job satisfaction and organizational commitment, creating a healthier and engaged workforce. This research contributes to the understanding of the dynamics of organizational commitment and job satisfaction among job order employees in the public sector.

Keywords: affective commitment, continuous commitment, normative commitment, job satisfaction

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Authors: Lesley Metibogun, Regan Potangaroa

Abstract:

Some existing sustainable public libraries in New Zealand now depend on air conditioning system for cooling. This seems completely contradictory to sustainable building initiatives. A sustainable building should be ‘self- sufficient’ and must aim at optimising the use of natural ventilation, wind and daylight and avoiding too much summer heat penetration into the building, to save energy consumption and enhance occupants’ comfort. This paper demonstrates that with appropriate architectural passive design input public libraries do not require air conditioning. Following a brief outline of how our dependence on air conditioning has spread over the full range of building types and climatic zones, this paper focuses on public libraries in temperate climates where passive cooling should be feasible for long periods of mild outside temperature. It was found that current design policies, regulations and guidelines and current building design practices militate passive cooling strategies. Perceived association with prestige, inflexibility of design process, rigid planning regulations and sustainability rating systems were identified as key factors forcing the need for air conditioning. Recommendations are made on how to further encourage development in this direction from the perspective of architectural design. This paper highlights how architectural passive cooling design strategies should be implemented in government initiated policies and regulations to develop a more sustainable public libraries.

Keywords: public library, sustainable design, temperate climate, passive cooling, air conditioning

Procedia PDF Downloads 245