Search results for: sieving particle size

Authors: Eman M. Eissa, Hany M. Hasanin, Mahmoud Abd-Elhamid, S. M. Muyeen, T. Fernando, H. H. C. Iu

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Among all available wind energy conversion systems (WECS), the direct driven permanent magnet synchronous generator integrated with power electronic interfaces is becoming popular due to its capability of extracting optimal energy capture, reduced mechanical stresses, no need to external excitation current, meaning less losses, and more compact size. Simple structure, low maintenance cost; and its decoupling control performance is much less sensitive to the parameter variations of the generator. This paper attempts to present a review of the control and optimization strategies of WECS based on permanent magnet synchronous generator (PMSG) and overview the most recent research trends in this field. The main aims of this review include; the generalized overall WECS starting from turbines, generators, and control strategies including converters, maximum power point tracking (MPPT), ending with DC-link control. The optimization methods of the controller parameters necessary to guarantee the operation of the system efficiently and safely, especially when connected to the power grid are also presented.

Keywords: control and optimization techniques, permanent magnet synchronous generator, variable speed wind turbines, wind energy conversion system

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Authors: Malinwo Estone Ayikpa

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Electric power systems are likely to operate with minimum losses and voltage meeting international standards. This is made possible generally by control actions provide by automatic voltage regulators, capacitors and transformers with on-load tap changer (OLTC). With the development of photovoltaic (PV) systems technology, their integration on distribution networks has increased over the last years to the extent of replacing the above mentioned techniques. The conventional analysis and simulation tools used for electrical networks are no longer able to take into account control actions necessary for studying distributed PV generation impact. This paper presents an unbalanced optimal power flow (OPF) model that minimizes losses with association of active power generation and reactive power control of single-phase and three-phase PV systems. Reactive power can be generated or absorbed using the available capacity and the adjustable power factor of the inverter. The unbalance OPF is formulated by current balance equations and solved by primal-dual interior point method. Several simulation cases have been carried out varying the size and location of PV systems and the results show a detailed view of the impact of PV distributed generation on distribution systems.

Keywords: distribution system, loss, photovoltaic generation, primal-dual interior point method

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Authors: Mejbri Sami, Zhani Khalifa, Zarzoum Kamel, Ben Bacha Habib, Koschikowski Joachim, Pfeifle Daniel

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Many places worldwide, especially arid and semi-arid remote regions, are suffering from the lack of drinkable water and the situation will be aggravated in the near future. Furthermore, remote areas are characterised by lack of conventional energy sources, skilled personnel and maintenance facilities. Therefore, the development of small to medium size, stand-alone and robust solar desalination systems is needed to provide independent fresh water supply in remote areas. This paper is focused on experimental studies on compact membrane distillation (MD) solar desalination prototype located at the Mechanical Engineering Department site, Kairouan University, Kairouan, Tunisia. The pilot system is designed and manufactured as a part of a research and development project funded by the MESRS/BMBF. The pilot system is totally autonomous. The electrical energy required to operate the unit is generated through a field of 4 m² of photovoltaic panels, and the heating of feed water is provided by a field of 6 m² of solar collectors. The Kairouan plant performance of the first few months of operation is presented. The highest freshwater production of 150 L/d is obtained on a sunny day in July of 633 W/m²d.

Keywords: experimental, membrane distillation, solar desalination, Permeat gap

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Authors: Wenqiu Cao

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Suicide prevention is a global problem that needs to be taken seriously. Investigating the mechanisms of suicide in major depressive disorder (MDD) separately through neuroimaging technology is essential for effective suicide prevention. And it’s particularly urgent in geriatric depressive patients since older adults are more likely to use rapidly deadly means, and suicidal behavior is more lethal for older adults. The current study reviews five studies related to suicide in geriatric MDD that uses neuroimaging methodology in order to analyze the relevant neurobiological mechanisms. The majority of the studies found significant white matter and grey matter reduction or lesion widespread in multiple brain regions, including the frontal and parietal regions, the midbrain, the external capsule, and the cerebellum. Regarding the cognitive impairment in geriatric MDD, the reward signals were found weakened in the paralimbic cortex. The functional magnetic resonance imaging (fMRI) studies also found hemodynamic changes in the right dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC), and right frontopolar cortex (FPC) regions in late-life MDD patients with suicidal ideation. Future studies should consider the age of depression onset, more accurate measurements of suicide, larger sample size, and longitudinal design.

Keywords: brain imaging, geriatric major depressive disorder, suicidality, suicide

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Authors: Aurora Cerri, Niko Pollojani

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The Tirana – Elbasan Road project is the most important highway project in Albania, constructed in the period May 2011 - ongoing. This project included construction of 38 km highway category road including 2.6 km of tunnel. It serves as a corridor connecting the Tirana, Capital of Albania and South-East area, and in the near future it is expected to continue in the direction of Macedonian border. Environmental Impact Assesment procedure for this project is provided by the Albanian Environmental Law No. 10431. This law establishes the regulation of procedures for identifying, assessment and reporting on the effects of certain projects on the environment, and the associated administrative procedures, during the decision-making process by the Ministry of Environment and Tourism for issuing environmental permit, and ensures that all relevant information concerning the environment are provided and considered. Due to the nature and size of the project, during the environmental impact assessment process, the European Union legislation, namely the EIA Directive 85/337 / EEC is considered. Moreover, in some cases, due to the lack of national standards and practical guidelines, when necessary those of EU member countries are considered. This paper presents an analysis of the EIA procedure followed on ‘Tirana – Elbasan’ Road project, with a focus on the application of the main stages of the procedure such as: screening, scoping, review, the EIA report; and consideration of alternatives, measures for impact prevention and reduction, and the public hearing T/discussion.

Keywords: highway, environmental impact assesment, Tirana, prevention

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Authors: Yousef Rostami Gharainy

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We look at the late financial exhibitions of China and India utilizing a simple growth accounting framework that creates assessments of the commitment of work, capital, training, and aggregate variable profitability for the three parts of agribusiness, industry, and administrations and in addition for the total economy. Our examination consolidates late information updates in both nations and incorporates broad examination of the basic information arrangement. The development records demonstrate a generally square with division in each nation between the commitments of capital gathering and TFP to development in yield every specialist over the period 1980-2007, and an increasing speed of development when the period is separated at 1993. Be that as it may, the size of yield development in China is generally twofold that of India at the total level, and additionally higher in each of the three segments in both sub-periods. In China the post-1993 increasing speed was amassed generally in industry, which contributed about 61 percent of China’s total efficiency development. Interestingly, 48 percent of the development in India in the second sub-period came in administrations. Reallocation of specialists from farming to industry and administrations has contributed 1.3 rate focuses to efficiency development in every nation.

Keywords: China, India, growth accounting framework, work, capital, training, aggregate variable profitability

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Authors: Chun-Ying Lee, Kuan-Hui Cheng, Mei-Wen Wu

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The nickel-manganese (Ni-Mn) alloy coating prepared from DC electrodeposition process in sulphamate bath was studied. The effects of process parameters, such as current density and electrolyte composition, on the cathodic current efficiency, microstructure, internal stress and mechanical properties were investigated. Because of its crucial effect on the application to the electroforming of microelectronic components, the development of low internal stress coating with high leveling power was emphasized. It was found that both the coating’s manganese content and the cathodic current efficiency increased with the raise in current density. In addition, the internal stress of the deposited coating showed compressive nature at low current densities while changed to tensile one at higher current densities. Moreover, the metallographic observation, X-ray diffraction measurement, transmission electron microscope (TEM) examination, and polarization curve measurement were conducted. It was found that the Ni-Mn coating consisted of nano-sized columnar grains and the maximum hardness of the coating was associated with (111) preferred orientation in the microstructure. The grain size was refined along with the increase in the manganese content of the coating, which accordingly, raised its hardness and mechanical tensile strength. In summary, the Ni-Mn coating prepared at lower current density of 1-2 A/dm2 had low internal stress, high leveling power, and better corrosion resistance.

Keywords: Ni-Mn coating, DC plating, internal stress, leveling power

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Authors: Mohammad Abdulaziz Algrnas, Emma Mulliner

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Housing projects have been established in Saudi Arabia, by both government and private construction companies, to meet the increasing demand from Saudi inhabitants across the country. However, the real estate market supply does not meet consumer preference requirements. Preferences normally differ depending on the consumer’s situation, such as the household’s sociological characteristics (age, household size and composition), resources (income, wealth, information and experience), tastes and priorities. Collecting information about consumer attitudes, preferences and perceptions is important for the real estate market in order to better understand housing demand and to ensure that this is met by appropriate supply. The aim of this paper is to identify consumer preferences for housing in Saudi Arabia. A quantitative closed-ended questionnaire was conducted with housing consumers in Saudi Arabia in order to gain insight into consumer needs, current household situation, preferences for a number of investigated housing attributes and consumers’ perceptions around the current housing problem. 752 survey responses were obtained and analysed in order to describe preferences for housing attributes and make comparisons between groups. Factor analysis was also conducted to identify and reduce the attributes. The results indicate a difference in preference according to the gender of the respondents and depending on their region of residence.

Keywords: housing attributes, Saudi Arabia, consumer preferences, housing preferences

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Authors: Muhammad Bilal Mustafa, Javed Hussain, Simeon Babatunde

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The Covid-19 pandemic has exposed the vulnerabilities of countless organisations beyond their size, type, and location. However, some groups and sectors are disproportionally get impacted by the pandemic. In the context of the UK, ethnic Small and Medium Enterprises (SMEs) turn out to be the most precarious group among all private sectors. Many ethnic SMEs shut down their business operations during a pandemic. A large portion of Black, Asian and minority ethnic (BAME) owners have huge concerns regarding their business’ survival and resilience. The current UK-centric studies have focused on the large business population, and there is a gap in ethnic SMEs and how they get affected by the Covid-19 pandemic. Moreover, there is a need to further knowledge and academic research to investigate the fundamental factors that could strengthen the resilience of ethnic SMEs as well as contribute to long-term sustainability. Therefore, this study aims to capture the effect of the Covid-19 pandemic on ethnic SMEs in the UK and assess the survival measures taken by ethnic SMEs during Covid-19. Besides, this study adopts a dynamic capabilities perspective that how firms' specific capabilities enable ethnic SMEs to exploit entrepreneurial opportunities during the Covid-19 pandemic. Finally, this research will help ethnic SMEs to develop vigorous resilience to address future external shocks and market uncertainties.

Keywords: COVID-19 pandemic, ethnic minority SMEs, entrepreneurial resilience, dynamic capabilities, sustainability

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Authors: Kumar Satyam Das, Murali Raghunathan

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This note discusses the feasibility of field development of a challenging shallow offshore field in South East Asia and how its learnings can be applied to marginal field development across the world especially developing marginal fields in this low oil price world. The field was found to be economically challenging even during high oil prices and the project was put on hold. Shell started development study with the aim to significantly reduce cost through competitively scoping and revive stranded projects. The proposed strategy to achieve this involved Improve Per platform recovery and Reduction in CAPEX. Methodology: Based on various Benchmarking Tool such as Woodmac for similar projects in the region and economic affordability, a challenging target of 50% reduction in unit development cost (UDC) was set for the project. Technical scope was defined to the minimum as to be a wellhead platform with minimum functionality to ensure production. The evaluation of key project decisions like Well location and number, well design, Artificial lift methods and wellhead platform type under different development concept was carried out through integrated multi-discipline approach. Key elements influencing per platform recovery were Wellhead Platform (WHP) location, Well count, well reach and well productivity. Major Findings: Reservoir being shallow posed challenges in well design (dog-leg severity, casing size and the achievable step-out), choice of artificial lift and sand-control method. Integrated approach amongst relevant disciplines with challenging mind-set enabled to achieve optimized set of development decisions. This led to significant improvement in per platform recovery. It was concluded that platform recovery largely depended on the reach of the well. Choice of slim well design enabled designing of high inclination and better productivity wells. However, there is trade-off between high inclination Gas Lift (GL) wells and low inclination wells in terms of long term value, operational complexity, well reach, recovery and uptime. Well design element like casing size, well completion, artificial lift and sand control were added successively over the minimum technical scope design leading to a value and risk staircase. Logical combinations of options (slim well, GL) were competitively screened to achieve 25% reduction in well cost. Facility cost reduction was achieved through sourcing standardized Low Cost Facilities platform in combination with portfolio execution to maximizing execution efficiency; this approach is expected to reduce facilities cost by ~23% with respect to the development costs. Further cost reductions were achieved by maximizing use of existing facilities nearby; changing reliance on existing water injection wells and utilizing existing water injector (W.I.) platform for new injectors. Conclusion: The study provides a spectrum of technically feasible options. It also made clear that different drivers lead to different development concepts and the cost value trade off staircase made this very visible. Scoping of the project through competitive way has proven to be valuable for decision makers by creating a transparent view of value and associated risks/uncertainty/trade-offs for difficult choices: elements of the projects can be competitive, whilst other parts will struggle, even though contributing to significant volumes. Reduction in UDC through proper scoping of present projects and its benchmarking paves as a learning for the development of marginal fields across the world, especially in this low oil price scenario. This way of developing a field has on average a reduction of 40% of cost for the Shell projects.

Keywords: benchmarking, full field development, CAPEX, feasibility

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Authors: Tanvi P. Patel, Warish D. Patel

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Association rule mining forms the core of data mining and it is termed as one of the well-known methodologies of data mining. Objectives of mining is to find interesting correlations, frequent patterns, associations or casual structures among sets of items in the transaction databases or other data repositories. Hence, association rule mining is imperative to mine patterns and then generate rules from these obtained patterns. For efficient targeted query processing, finding frequent patterns and itemset mining, there is an efficient way to generate an itemset tree structure named Memory Efficient Itemset Tree. Memory efficient IT is efficient for storing itemsets, but takes more time as compare to traditional IT. The proposed strategy generates maximal frequent itemsets from memory efficient itemset tree by using levelwise pruning. For that firstly pre-pruning of items based on minimum support count is carried out followed by itemset tree reconstruction. By having maximal frequent itemsets, less number of patterns are generated as well as tree size is also reduced as compared to MEIT. Therefore, an enhanced approach of memory efficient IT proposed here, helps to optimize main memory overhead as well as reduce processing time.

Keywords: association rule mining, itemset mining, itemset tree, meit, maximal frequent pattern

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Authors: Wei Zheng, Mao Ji, Zhe Hou, Meng Huang, Bo Qi

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The transformer is the key equipment of the power system. Winding deformation is one of the main transformer defects, and timely and effective detection of the transformer winding deformation can ensure the safe and stable operation of the transformer to the maximum extent. When winding deformation occurs, the size, shape and spatial position of the winding will change, which directly leads to the change of magnetic flux leakage distribution. Therefore, it is promising to study the online detection method of the transformer winding deformation based on magnetic flux leakage characteristics, in which the key step is to study the optimal placement method of magnetic flux leakage sensors inside the transformer. In this paper, a simulation model of the transformer winding deformation is established to obtain the internal magnetic flux leakage distribution of the transformer under normal operation and different winding deformation conditions, and the law of change of magnetic flux leakage distribution due to winding deformation is analyzed. The results show that different winding deformation leads to different characteristics of the magnetic flux leakage distribution. On this basis, an optimized placement of magnetic flux leakage sensors inside the transformer is proposed to provide a basis for the online detection method of transformer winding deformation based on the magnetic flux leakage characteristics.

Keywords: magnetic flux leakage, sensor placement method, transformer, winding deformation

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Authors: Voodi Kalandhar, Veera Reddy, Yuva Tejasree

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Researchers have become interested in multilevel inverters (MLI) because of their potential for medium- and high-power applications. MLIs are becoming more popular as a result of their ability to generate higher voltage levels, minimal power losses, small size, and low price. These inverters used in high voltage and high-power applications because the stress on the switch is low. Even though many traditional topologies, such as the cascaded H-bridge MLI, the flying capacitor MLI, and the diode clamped MLI, exist, they all have some drawbacks. A complicated control system is needed for the flying capacitor MLI to balance the voltage across the capacitor and diode clamped MLI requires more no of diodes when no of levels increases. Even though the cascaded H-Bridge MLI is popular in terms of modularity and simple control, it requires more no of isolated DC source. Therefore, a topology with fewer devices has always been necessary for greater efficiency and reliability. A new single-phase MLI topology has been introduced to minimize the required switch count in the circuit and increase output levels. With 3 dc voltage sources, 8 switches, and 13 levels at the output, this new single- phase MLI topology was developed. To demonstrate the proposed converter's superiority over the other MLI topologies currently in use, a thorough analysis of the proposed topology will be conducted.

Keywords: DC-AC converter, multi-level inverter (MLI), diodes, H-bridge inverter, switches

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Authors: Marcelle Muriel Domkam Tchunkam, Rolin Feudjio

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This work investigates the ultrastructure, physicochemical and thermal properties evaluation of Palm Kernel Shells (PKS). PKS Tenera waste samples were obtained from a palm oil mill in Dizangué Sub-Division, Littoral region of Cameroon, while PKS Dura waste samples were collected from the Institute of Agricultural Research for Development (IRAD) of Mbongo. A sodium hydroxide solution was used to wash the shells. They were then rinsed by demineralised water and dried in an oven at 70 °C during 72 hours. They were then grounded and sieved to obtained powders from 0.04 mm to 0.45 mm in size. Transmission Electron Microscopy (TEM) and Surface Electron Microscopy (SEM) were used to characterized powder samples. Chemical compounds and elemental constituents, as well as thermal performance were evaluated by Van Soest Method, TEM/EDXA and SEM/EDS techniques. Thermal characterization was also performed using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Our results from microstructural analysis revealed that most of the PKS material is made of particles with irregular morphology, mainly amorphous phases of carbon/oxygen with small amounts of Ca, K, and Mg. The DSC data enabled the derivation of the materials’ thermal transition phases and the relevant characteristic temperatures and physical properties. Overall, our data show that PKS have nanopores and show potential in 3D printing and membrane filtration applications.

Keywords: DSC, EDXA, palm kernel shells, SEM, TEM

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Authors: John M. Lyne, K. Andrea Scott

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In fluid dynamics, direct numerical simulations (DNS) of turbulent flows require large amounts of nodes to appropriately resolve all scales of energy transfer. Due to the size of these databases, sharing these datasets amongst the academic community is a challenge. Recent work has been done to investigate the use of super-resolution to enable database sharing, where a low-resolution flow field is super-resolved to high resolutions using a neural network. Recently, Generative Adversarial Networks (GAN) have grown in popularity with impressive results in the generation of faces, landscapes, and more. This work investigates the generation of unique high-resolution channel flow velocity fields from a low-dimensional latent space using a GAN. The training objective of the GAN is to generate samples in which the distribution of the generated samplesis ideally indistinguishable from the distribution of the training data. In this study, the network is trained using samples drawn from a statistically stationary channel flow at a Reynolds number of 560. Results show that the turbulent statistics and energy spectra of the generated flow fields are within reasonable agreement with those of the DNS data, demonstrating that GANscan produce the intricate multi-scale phenomena of turbulence.

Keywords: computational fluid dynamics, channel flow, turbulence, generative adversarial network

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Authors: Qiaohui Zhong, Yiqi Kuang, Wanxun Cai, Libin Huang

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As a community public facility, the popularity and perfection of old clothes recycling products directly affect people's impression of the whole city, which is related to the happiness index of residents' lives and is of great significance to the construction of eco-civilized cities and the realization of sustainable urban development. At present, China's waste clothing is characterized by large production and a high utilization rate, but the current rate of old clothes recycling is low, and the ‘one-size-fits-all’ recycling model makes people's motivation for old clothes recycling low, and old clothes recycling is in a dilemma. Based on the two online and offline recycling modes of old clothes recycling in Chinese communities, this paper conducts an in-depth survey on the public, operators, and regulators from the aspects of activity scene analysis, crowd attributes analysis, and community space analysis summarizes the difficulties of old clothes recycling for the public - nowhere to recycle, inconvenient to recycle and unwilling to recycle, and analyzes the factors that lead to these difficulties, and gives a solution with foreign experience to solve these problems. It also analyzes the factors that lead to these difficulties and gives targeted suggestions in combination with foreign experience, exploring and proposing a set of appropriate modern old-clothes recycling modes.

Keywords: community, old clothes recycling, recycling mode, sustainable urban development

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Authors: Itumeleng Judith Maome, Robert Walter Dumisani Zondo

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The concept of Corporate Social Responsibility (CSR) has gained popularity as a management philosophy in companies. They integrate social and environmental concerns into their operations and interactions with stakeholders. While CSR has mostly been associated with large organisations, it contributes to societal goals by engaging in activities or supporting volunteering or ethically oriented practices. However, small and medium enterprises (SMEs) have been recognised for their contributions to the social and economic development of any country. Consequently, this study examines the effect of CSR practices on human resource performance in the selected manufacturing SME in South Africa. This study was quantitative in design and examined the production and related experiences of the manufacturing SME organisation that had adopted a CSR strategy for human resource improvement. The study was achieved by collecting pre- and post-quarterly data, overtime, for employee turnover and labour absenteeism for analysis using the regression model. The results indicate that both employee turnover and labour absenteeism have no relationship with human resource performance post-CSR implementation. However, CSR has a relationship with human resource performance. Any increase in CSR activities results in an increase in human resource performance.

Keywords: corporate social responsibility, employee turnover, human resource, labour absenteeism, manufacturing SME

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Authors: Surinder Pal Singh, Sanjay Goel

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The paper presents results of an investigation conducted to study the flexural fatigue characteristics of Self Compacting Concrete (SCC) and Self Compacting Fibre Reinforced Concrete (SCFRC). In total 360 flexural fatigue tests and 270 static flexural strength tests were conducted on SCC and SCFRC specimens to obtain the fatigue test data. The variability in the distribution of fatigue life of SCC and SCFRC have been analyzed and compared with that of NVC and NVFRC containing steel fibres of comparable size and shape. The experimental coefficients of fatigue equations have been estimated to represent relationship between stress level (S) and fatigue life (N) for SCC and SCFRC containing different fibre volume fractions. The probability of failure (Pf) has been incorporated in S-N relationships to obtain families of S-N-Pf relationships. A good agreement between the predicted curves and those obtained from the test data has been observed. The fatigue performance of SCC and SCFRC has been evaluated in terms of two-million cycles fatigue strength/endurance limit. The theoretic fatigue lives were also estimated using single-log fatigue equation for 10% probability of failure to estimate the enhanced extent of theoretic fatigue lives of SCFRC with reference to SCC and NVC. The reduction in variability in the fatigue life, increased endurance limit and increased theoretiac fatigue lives demonstrates an overall better fatigue performance for SCC and SCFRC.

Keywords: fatigue life, fibre, probability of failure, self-compacting concrete

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Authors: Peter U. Eze, P. Udaya, Robin J. Evans

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Data hiding can be achieved by Steganography or invisible digital watermarking. For digital watermarking, both accurate retrieval of the embedded watermark and the integrity of the cover image are important. Medical image security in Teleradiology is one of the applications where the embedded patient record needs to be extracted with accuracy as well as the medical image integrity verified. In this research paper, the Constant Correlation Spread Spectrum digital watermarking for medical image tamper detection and accurate embedded watermark retrieval is introduced. In the proposed method, a watermark bit from a patient record is spread in a medical image sub-block such that the correlation of all watermarked sub-blocks with a spreading code, W, would have a constant value, p. The constant correlation p, spreading code, W and the size of the sub-blocks constitute the secret key. Tamper detection is achieved by flagging any sub-block whose correlation value deviates by more than a small value, ℇ, from p. The major features of our new scheme include: (1) Improving watermark detection accuracy for high-pixel depth medical images by reducing the Bit Error Rate (BER) to Zero and (2) block-level tamper detection in a single computational process with simultaneous watermark detection, thereby increasing utility with the same computational cost.

Keywords: Constant Correlation, Medical Image, Spread Spectrum, Tamper Detection, Watermarking

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Authors: Noman Ahmed, Fariha Tahseen

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Since several decades, unplanned urbanization and rapid growth of informal settlements have evolved and increased in size and number. Large cities such as Karachi have been impacted with sprawl and rising share of unplanned settlements where poor communities reside. Threats of eviction, deteriorating law and order situation, lack of essential amenities and infrastructure, extortion and bullying from local and non-local musclemen and feeble response of government agencies towards their development needs are some predicaments. Non-governmental organizations (NGOs) have caused important interventions in such locations. Appraisal of the community-based mapping as a tool in supporting the development work in less privileged areas in Karachi has been the objective of this research. The Orangi Pilot Project (OPP), under the leadership of its slain director Perween Rahman had a significant role to play in developing and extending this approach in low income locations in Karachi and beyond. The paper investigates the application of mapping in the process of peri urban land invasion causing rapid transformation of traditional settlements in Karachi. Mixed methodology components comprising literature review, archival research, and unstructured interviews with key informants and case studies have been used.

Keywords: squatters (katchi abadis), land grabbing, community empowerment, housing rights, mapping, infrastructure development

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Authors: Francis Sichimba

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Literature has increasingly acknowledged the important role that grandparents play in child care with evidence highlighting differences in grand-parental investment between countries and cultures. However, there are very few systematic cross cultural studies on grandparents’ participation in child care. Thus, we decided to conduct this study in Zambia and the Netherlands because the two countries differ rather drastically socially and culturally. The objective of this study was to investigate grand-parental involvement in child care in Zambia and the Netherlands. In line with the general objective, four hypotheses were formulated using nationality, family size, social economic status (SES), attachment security as independent variables. The study sample consisted of 411 undergraduate students from the University of Zambia and the University of Leiden. A questionnaire was used to measure grand-parental involvement in child care. Results indicated that grandparent involvement in child care was prevalent in both Zambia and Netherlands. However, as predicted it was found that Zambian grandparents (M = 9.69, SD=2.40) provided more care for their grandchildren compared to their Dutch counterparts (M = 7.80, SD=3.31) even after controlling for parents being alive. Using hierarchical logistic regression analysis the study revealed that nationality and attachment-related avoidance were significant predictors of grand-parental involvement in child care. It was concluded that grand-parental care is a great resource in offering complementary care in both countries.

Keywords: attachment, care, grand-parenting involvement, social economic status

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Authors: M. H. Shwehdi, S. Raja Mohammad

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Recently energy savings have become more pronounced as a result of the world financial crises as well the unstable oil prices. Certainly all entities needs to adapt Energy Conservation and Management Strategies due to high monthly consumption of their spread locations and advancements of its telecom systems. These system improvements necessitate the establishment of more exchange centers as well provide energy savings. This paper investigates the impact of HVAC System Characteristics, Operational Strategies, the impact of Envelope Thermal Characteristics, and energy conservation measures. These are classified under three types of measures i.e. Zero-Investment; Low-Investment and High-Investment Energy Conservation Measures. The study shows that the Energy Conservation Measures (ECMs) pertaining to the HVAC system characteristics and operation represent the highest potential for energy reduction, attention should be given to window thermal and solar radiation characteristics when large window areas are used. The type of glazing system needs to be carefully considered in the early design phase of future buildings. Paper will present the thermal optimization of different size centers in the two hot-dry and hot-humid Saudi Arabian city of Al Khobar, East province.

Keywords: energy conservation, optimization, thermal design, intermittent operation, exchange centers, hot-humid climate, Saudi Arabia

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Authors: Olanike O. Akinwale, Isiaka S. Adedoyin

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Revenue is a fund realized by the government to meet both current and capital expenditures. The study found out the various ways through which local governments in Nigeria generate revenue or obtain funds and determined whether the people of Boripe local government are paying tax as at when due and also evaluated how the revenue generated is being used by the local government. During the course of this study, research questionnaires were drafted and distributed to respondents in the local government secretariat who supplied the information needed to carry out the research work. Data were collected by using simple random sampling technique where members of the population have been given equal chance of being picked as a member of the sample. Data were analysed using chart table; the chart analyzed the figure of the past two years revenue and expenditure of the local government. It was deduced from the result that revenue generated but this was not up to what one expected for this local government to finance the projected expenditure when the size was considered, its location as well as its natural endowment of this local government. This was due to lack of cooperation of the people and staffs within the local government in the local government jurisdiction as well as fraudulent activities the revenue collectors engaged in. Revenue generation is a fuel for development in any organization whether public or private. The ability of revenue drive of Boripe was not strong enough since the targeted revenue from taxation was not enough to meet the projected expenditure for a particular year as in 2016, the difference was carried forward to the next year.

Keywords: appraisal, expenditure, local government, questionnaire, revenue

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Authors: Hassan S. Naeini

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Nowadays a lot of people are working in several sorts of industrial sectors in which there are some risk factors which threaten human being especially in developing countries. One of the main problems which effect on workers’ health refers to Ergonomics. Ergonomics as multidisciplinary science concerns workers’ health and safety in terms of somatic and mental concepts. Surely ergonomics interventions and improvement make a better condition for workers and change the quality of working life to better condition. In this study, one of the factories in Iran which is producing some kinds of small and medium size of refrigerators was chosen as the sample. The preliminary ergonomics observation of the mentioned factory showed that there are some risk factors in terms of ergonomics aspects, so an ergonomic intervention was defined, then some ergonomic assessment methods such as NMQ,OWAS, and Environmental Ergonomic Assessment were used. Also Anthropometric measurement was done. This study shows that there are some workstations and plants which suffer some degrees of ergonomic problems. Considering with the gathered data, illumination, noise control and workstation design in metal workstation are known as the priority actions. Some parts of the mentioned interventions are ongoing actions. it seems that the mentioned intervention and workstations design make a better condition for workers, because ergonomics make a safer and more sustainable environments for human being.

Keywords: anthropometry, ergonomics, health, NMQ, OWAS

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Authors: A.D. Susanti, W. B. Sediawan, S.K. Wirawan, Budhijanto, Ritmaleni

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Oryzanol content in rice bran oil (RBO) naturally has high antioxidant activity. Its reviewed has several health properties and high interested in pharmacy, cosmetics, and nutrition’s. Because of the low concentration of oryzanol in crude RBO (0.9-2.9%) then its need to be further processed for practical usage, such as via adsorption process. In this study, investigation and adjustment of adsorption equilibrium models were conducted through the kinetic data approachments. Mathematical modeling on kinetics of batch adsorption of oryzanol separation from RBO has been set-up and then applied for equilibrium results. The size of adsorbent particles used in this case are usually relatively small then the concentration in the adsorbent is assumed to be not different. Hence, the adsorption rate is controlled by the rate of oryzanol mass transfer from the bulk fluid of RBO to the surface of silica gel. In this approachments, the rate of mass transfer is assumed to be proportional to the concentration deviation from the equilibrium state. The equilibrium models applied were Langmuir, coefficient distribution, and Freundlich with the values of the parameters obtained from equilibrium results. It turned out that the models set-up can quantitatively describe the experimental kinetics data and the adjustment of the values of equilibrium isotherm parameters significantly improves the accuracy of the model. And then the value of mass transfer coefficient per unit adsorbent mass (kca) is obtained by curve fitting.

Keywords: adsorption equilibrium, adsorption kinetics, oryzanol, rice bran oil

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Authors: Ella Zahra

Abstract:

Sea urchins are keystone species in many global benthic ecosystems. The concentration of microplastics (MPs) in sea urchin organs was quantified in 120 individuals of 2 different species and from 4 sites across the Greek island Lipsi, with special interest in the differences between the native Arbacia lixula and the invasive Diadema setosum. Over 93% of MPs observed in both species were fibrous. MP abundance was found to correlate with exposure to open sea and harsh prevailing winds, irrespective of proximity to urban activities. The MP abundance in the invasive species was not found to be significantly dependent on site. Interestingly, the smaller native species contained significantly larger sized MPs than the invasive, possibly as a result of a greater feeding rate in A. lixula individuals. Sexually immature urchins may also have a higher feeding rate, giving rise to the negative correlation between gonad index and MPs per individual. The size of MPs ranged from 10µm to 24210µm, heavily skewed towards smaller particles. Few differences in colour were noted between the species and sites. MPs were detected in 100% of the samples with abundance ranging from 19.27 ± 6.77 to 26.83 ± 8.15 items per individual, or 3.55 ± 3.73 to 7.34 ± 10.51 items per gram of wet organ weight. This high value could lead to health risks in East Asia and the Mediterranean, where sea urchin is widely consumed, due to toxins adsorbed to the MPs.

Keywords: microplastics, plastic pollution, invertebrate ecology, invasive marine species

Procedia PDF Downloads 106

Authors: Edson Vengesai

Abstract:

Derivative products have become essential instruments in portfolio diversification, price discovery, and, most importantly, risk hedging. Derivatives are complex instruments; their valuation, volatility implications, and real impact on the underlying assets' behaviour are not well understood. Little is documented empirically, with conflicting conclusions on how these instruments affect firm risk exposures. Given the growing interest in using derivatives in risk management and portfolio engineering, this study examines the practical impact of derivative usage on the underlying stock price exposure and systematic risk. The paper uses data from South African listed firms. The study employs GARCH models to understand the effect of derivative uses on conditional stock volatility. The GMM models are used to estimate the effect of derivatives use on stocks' systematic risk as measured by Beta and on the total risk of stocks as measured by the standard deviation of returns. The results provide evidence on whether derivatives use is instrumental in reducing stock returns' systematic and total risk. The results are subjected to numerous controls for robustness, including financial leverage, firm size, growth opportunities, and macroeconomic effects.

Keywords: derivatives use, hedging, volatility, stock price exposure

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Authors: Mohammad Jalali Varnamkhasti

Abstract:

The genetic algorithms have been very successful in handling difficult optimization problems. The fundamental problem in genetic algorithms is premature convergence. This paper, present a new fuzzy genetic algorithm based on chaotic values instead of the random values in genetic algorithm processes. In this algorithm, for initial population is used chaotic sequences and then a new sexual selection proposed for selection mechanism. In this technique, the population is divided such that the male and female would be selected in an alternate way. The layout of the male and female chromosomes in each generation is different. A female chromosome is selected by tournament selection size from the female group. Then, the male chromosome is selected, in order of preference based on the maximum Hamming distance between the male chromosome and the female chromosome or The highest fitness value of male chromosome (if more than one male chromosome is having the maximum Hamming distance existed), or Random selection. The selections of crossover and mutation operators are achieved by running the fuzzy logic controllers, the crossover and mutation probabilities are varied on the basis of the phenotype and genotype characteristics of the chromosome population. Computational experiments are conducted on the proposed techniques and the results are compared with some other operators, heuristic and local search algorithms commonly used for solving p-median problems published in the literature.

Keywords: genetic algorithm, fuzzy system, chaos, sexual selection

Procedia PDF Downloads 385

Authors: Ilma Robo, Saimir Heta, Edona Hasanaj, Vera Ostreni

Abstract:

The hybrid layer, the way it is created and how it is protected against degradation over time, is the key to the clinical success of a composite restoration. The composite supports the dentinal structure exactly with the realized surface of microretension. Thus, this surface is in direct proportion to its size versus the duration of clinical use of composite dental restoration. Micro-retention occurs between dentin or acidified enamel and adhesive resin extensions versus pre-prepared spaces, such as hollow dentinal tubules. The way the adhesive resin binds to the acidified dentinal structure depends on the physical or chemical factors of this interrelationship between two structures with very different characteristics. During the acidification process, a precursor to the placement of the adhesive resin layer, activation of metaloproteinases of dental origin occurs, enzymes which are responsible for the degradation of the hybrid layer. These enzymes have expressed activity depending on the presence of Zn2 + or Ca2 + ions. There are several ways to inhibit these enzymes, and consequently, there are several ways to inhibit the degradation process of the hybrid layer. The study aims to evaluate chlorhexidine as a solution element, inhibitor of dentin activated metalloproteinases, as a result of the application of acidification. This study aims to look at this solution in advantage or contraindication theories, already published in the literature.

Keywords: hybrid layer, chlorhexidine, degradation, application

Procedia PDF Downloads 133

Authors: Zeynep Busra Velioglu, Deniz Pulat, Beril Demirbakan, Burak Ozcan, Ece Bayrak, Cevat Erisken

Abstract:

Bone tissue has the ability to perform a wide array of functions including providing posture, load-bearing capacity, protection for the internal organs, initiating hematopoiesis, and maintaining the homeostasis of key electrolytes via calcium/phosphate ion storage. The most common cause for bone defects is extensive trauma and subsequent infection. Bone tissue has the self-healing capability without a scar tissue formation for the majority of the injuries. However, some may result with delayed union or fracture non-union. Such cases include reconstruction of large bone defects or cases of compromised regenerative process as a result of avascular necrosis and osteoporosis. Several surgical methods exist to treat bone defects, including Ilizarov method, Masquelete technique, growth factor stimulation, and bone replacement. Unfortunately, these are technically demanding and come with noteworthy disadvantages such as lengthy treatment duration, adverse effects on the patient’s psychology, repeated surgical procedures, and often long hospitalization times. These limitations associated with surgical techniques make bone substitutes an attractive alternative. Here, it was hypothesized that a 3D printed scaffold will mimic trabecular bone in terms of biomechanical properties and that such scaffolds will support cell attachment and survival. To test this hypothesis, this study aimed at fabricating poly(lactic acid), PLA, structures using 3D printing technology for trabecular bone defects, characterizing the scaffolds and comparing with bovine trabecular bone. Capacity of scaffolds on human bone marrow stem cell (hBMSC) attachment and survival was also evaluated. Cubes with a volume of 1 cm³ having pore sizes of 0.50, 1.00 and 1.25 mm were printed. The scaffolds/grafts were characterized in terms of porosity, contact angle, compressive mechanical properties as well cell response. Porosities of the 3D printed scaffolds were calculated based on apparent densities. For contact angles, 50 µl distilled water was dropped over the surface of scaffolds, and contact angles were measured using ‘Image J’ software. Mechanical characterization under compression was performed on scaffolds and native trabecular bone (bovine, 15 months) specimens using a universal testing machine at a rate of 0.5mm/min. hBMSCs were seeded onto the 3D printed scaffolds. After 3 days of incubation with fully supplemented Dulbecco’s modified Eagle’s medium, the cells were fixed using 2% formaldehyde and glutaraldehyde mixture. The specimens were then imaged under scanning electron microscopy. Cell proliferation was determined by using EZQuant dsDNA Quantitation kit. Fluorescence was measured using microplate reader Spectramax M2 at the excitation and emission wavelengths of 485nm and 535nm, respectively. Findings suggested that porosity of scaffolds with pore dimensions of 0.5mm, 1.0mm and 1.25mm were not affected by pore size, while contact angle and compressive modulus decreased with increasing pore size. Biomechanical characterization of trabecular bone yielded higher modulus values as compared to scaffolds with all pore sizes studied. Cells attached and survived in all surfaces, demonstrating higher proliferation on scaffolds with 1.25mm pores as compared with those of 1mm. Collectively, given lower mechanical properties of scaffolds as compared to native bone, and biocompatibility of the scaffolds, the 3D printed PLA scaffolds of this study appear as candidate substitutes for bone repair and regeneration.

Keywords: 3D printing, biomechanics, bone repair, stem cell

Procedia PDF Downloads 172