Search results for: IoT embedded electronics

Authors: Randhir Singh Ranta

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The attempt to achieve and maintain an optimum state of health has always drilled the human mind and consequently, a number of healing systems have evolved around the world. Communities have contrived procedures to alleviate the wearisome condition arising out of ailments, using their own system, which differ from one community to another. Each culture has evolved a viewpoint regarding the cause of disease and the same is embedded in their belief systems. In India, the elementary proposition of mental health is within the community. From the theoretical perspective, the individual obeying and adhering to the institution of village deity represents the two changeovers i.e. from biological to psychological and from psychological to spiritual. In order to understand the cultural notion of mental health and role of local deities, a study was conducted in North-western Himalaya with a purpose to study the belief system of people in context of institution of village deity and establish a relationship between religiosity and general well-being among the believers. An effort was made to compare the mental health status of people facing psychosomatic disorders with the normal. Quantitative and qualitative methods were used for the purpose. Case studies were made to have an understanding of nature of mental and behavioural disorders and the role of institutions of local deities in managing the same. The results revealed that mountain communities have firm beliefs in local deities. A significant difference was found on the scores of belief and wellbeing, and a positive correlation was found between the belief assessment and general wellbeing.

Keywords: culture notion, mental health, healing system, deities

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Authors: Aamir Mubashar, Ibrahim Fiaz

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This research presents a three-dimensional finite element modelling strategy to simulate damage in a quasi-static three-point bending analysis of woven twill 2/2 type carbon fibre reinforced plastic (CFRP) composite on a micro-meso level using cohesive zone modelling technique. A meso scale finite element model comprised of a number of plies was developed in the commercial finite element code Abaqus/explicit. The interfaces between the plies were explicitly modelled using cohesive zone elements to allow for debonding by crack initiation and propagation. Load-deflection response of the CRFP within the quasi-static range was obtained and compared with the data existing in the literature. This provided validation of the model at the global scale. The outputs resulting from the global model were then used to develop a simulation model capturing the micro-meso scale material features. The sub-model consisted of a refined mesh representative volume element (RVE) modelled in texgen software, which was later embedded with cohesive elements in the finite element software environment. The results obtained from the developed strategy were successful in predicting the overall load-deflection response and the damage in global and sub-model at the flexure limit of the specimen. Detailed analysis of the effects of the micro-scale features was carried out.

Keywords: woven composites, multi-scale modelling, cohesive zone, finite element model

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Authors: Yuzman Yusoff, Siti Noor Harun, Noor Shelida Salleh, Tan Kong Yew

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This paper presents the design and characterization of analog readout interface circuits for ion sensitive field effect transistor (ISFET) and ion selective electrode (ISE) based sensor. These interface circuits are implemented using MIMOS’s 0.35um CMOS technology and experimentally characterized under 24-leads QFN package. The characterization evaluates the circuit’s functionality, output sensitivity and output linearity. Commercial sensors for both ISFET and ISE are employed together with glass reference electrode during testing. The test result shows that the designed interface circuits manage to readout signals produced by both sensors with measured sensitivity of ISFET and ISE sensor are 54mV/pH and 62mV/decade, respectively. The characterized output linearity for both circuits achieves above 0.999 rsquare. The readout also has demonstrated reliable operation by passing all qualifications in reliability test plan.

Keywords: readout interface circuit (ROIC), analog interface circuit, ion sensitive field effect transistor (ISFET), ion selective electrode (ISE), ion sensor electronics

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Authors: Ali Hajiesmaeili, Mehdi Rahimi, Ehsan Jaberi, Amir Abbas Hosseini

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The purpose of this study is investigating the influences of logistics performance on organizational performance including both marketing & financial aspects, and showing the financial impacts of selecting the right marketing and logistics priorities in line with their supply chain type, and also giving the practitioners an advance identification of their priorities and participation types of supply chain, and the best combination of their strategies and resources in this regard. We made use of the original model’s questionnaire to gather all expert’s data and also SPSS and AMOS Ver.22 to analyze the gathered data. CFA method was also used to test whether a relationship between observed variables and their underlying latent constructs exists. Supply chain strategy implementation leads to logistics performance improvement, and marketing performance will be affected as well. Logistics service providers should focus on enhancement of supply chain performance, since logistics performance has been considered as a basis of evaluation of supply chain management strategy. Consequently, performance of the organization will be enhanced. This case is the first research made in Iran that analyzes the relationship between Logistics & Organizational performance in Home Appliances and Home Entertainment companies.

Keywords: logistics, organizational, performance, supply chain, strategy

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Authors: S. Forel, F. Bouanis, L. Catala, I. Florea, V. Huc, F. Fossard, A. Loiseau, C. Cojocaru

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Single wall carbon nanotubes are seen as excellent candidate for application on nanoelectronic devices because of their remarkable electronic and mechanical properties. These unique properties are highly dependent on their chiral structures and the diameter. Therefore, structure controlled growth of SWNTs, especially directly on final device’s substrate surface, are highly desired for the fabrication of SWNT-based electronics. In this work, we present a new approach to control the diameter of SWNTs and eventually their chirality. Because of their potential to control the SWNT’s chirality, bi-metalics nanoparticles are used to prepare alloy nanoclusters with specific structure. The catalyst nanoparticles are pre-formed following a previously described process. Briefly, the oxide surface is first covered with a SAM (self-assembled monolayer) of a pyridine-functionalized silane. Then, bi-metallic (Fe-Ru, Co-Ru and Ni-Ru) complexes are assembled by coordination bonds on the pre-formed organic SAM. The resultant alloy nanoclusters were then used to catalyze SWNTs growth on SiO2/Si substrates via CH4/H2 double hot-filament chemical vapor deposition (d-HFCVD). The microscopy and spectroscopy analysis demonstrate the high quality of SWNTs that were furthermore integrated into high-quality SWNT-FET.

Keywords: nanotube, CVD, device, transistor

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Authors: Shahriar Sepahvand, Mohammad Ali Davarpanah

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Infections caused by Acinetobacter baumannii are among the common hospital-acquired infections that have seen an increase in antibiotic resistance in recent years. Colistin is the last treatment option against this pathogen. The aim of this study is to investigate the histopathology of BALB/C mice receiving sensitive and resistant strains of Acinetobacter baumannii to colistin. A total of 68 female laboratory mice weighing 30 to 40 grams of the BALB/C breed were studied in this research for three weeks under appropriate laboratory conditions in terms of food and environment. The experimental groups included: control group, second group, third group, fourth group. Lung, liver, spleen, and kidney tissues were removed from anesthetized mice and, after washing in physiological serum, were fixed in 10% formalin for 14 days. For dehydration, alcohol with ascending degrees of 70, 80, 90, and 100 was used. After clearing and soaking in paraffin, the samples were embedded in paraffin. Then, sections with a thickness of 5 microns were prepared and, after staining by hematoxylin-eosin, the samples were ready for study with a light microscope. In liver, spleen, lung, and kidney tissues of mice receiving the colistin-sensitive strain of Acinetobacter baumannii, infiltration of inflammatory cells and hyperemia were observed compared to control group mice. Liver and lung tissues of mice receiving strains of Acinetobacter baumannii resistant to colistin showed tissue destruction in addition to infiltration of inflammatory cells and hyperemia, with more destruction observed in lung tissue.

Keywords: acinetobacter baumannii, colistin antibiotic, histopathological examination, resistant

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Authors: Ayesha Khatun

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In 21st century where markets are unstable, technologies rapidly proliferate, competitors multiply, products and services become obsolete almost overnight and customers demand low cost high value product, leveraging and harnessing knowledge is not just a potential source of competitive advantage rather a necessity in technology based and information intensive industries. Knowledge management focuses on leveraging the available knowledge and sharing the same among the individuals in the organization so that the employees can make best use of it towards achieving the organizational goals. Knowledge is not a discrete object. It is embedded in people and so difficult to transfer outside the immediate context that it becomes a major competitive advantage. However, internal transfer of knowledge among the employees is essential to maximize the use of knowledge available in the organization in an unstructured manner. But as knowledge is the source of competitive advantage for the organization it is also the source of competitive advantage for the individuals. People think that knowledge is power and sharing the same may lead to lose the competitive position. Moreover, the very nature of tacit knowledge poses many difficulties in sharing the same. But sharing tacit knowledge is the vital part of knowledge management process because it is the tacit knowledge which is inimitable. Knowledge management has been made synonymous with the use of software and technology leading to the management of explicit knowledge only ignoring personal interaction and forming of informal networks which are considered as the most successful means of sharing tacit knowledge. Factors responsible for effective sharing of tacit knowledge are grouped into –individual, organizational and technological factors. Different factors under each category have been identified. Creating a positive organizational culture, encouraging personal interaction, practicing reward system are some of the strategies that can help to overcome many of the barriers to effective sharing of tacit knowledge. Methodology applied here is completely secondary. Extensive review of relevant literature has been undertaken for the purpose.

Keywords: knowledge, tacit knowledge, knowledge management, sustainable competitive advantage, organization, knowledge sharing

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Authors: Rahmat Ali, Inamullah Khan, Amjad Naseer, Abid A. Shah

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Hydronic Heating and Cooling systems in concrete slab based buildings are increasingly becoming a popular substitute to conventional heating and cooling systems. In exploring the materials, techniques employed, and their relative performance measures, a fair bit of uncertainty exists. This research has identified the simplest method of determining the thermal field of a single hydronic pipe when acting as a part of a concrete slab, based on which the spacing and positioning of pipes for a best thermal performance and surface temperature control are determined. The pipe material chosen is the commonly used PEX pipe, which has an all-around performance and thermal characteristics with a thermal conductivity of 0.5W/mK. Concrete Test samples were constructed and their thermal fields tested under varying input conditions. Temperature sensing devices were embedded into the wet concrete at fixed distances from the pipe and other touch sensing temperature devices were employed for determining the extent of the thermal field and validation studies. In the first stage, it was found that the temperature along a specific distance was the same and that heat dissipation occurred in well-defined layers. The temperature obtained in concrete was then related to the different control parameters including water supply temperature. From the results, the temperature of water required for a specific temperature rise in concrete is determined. The thermally effective area is also determined which is then used to calculate the pipe spacing and positioning for the desired level of thermal comfort.

Keywords: thermally activated building systems, concrete slab temperature, thermal field, energy efficiency, thermal comfort, pipe spacing

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Authors: Rose Lastovicka, Bernard Guy, Diana Burton

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Greek myth and art acted as tools to think with, and a lens through which to explore complex topics as a form of social media. In particular, coins were a form of propaganda to communicate the wealth and power of the city-states they originated from as they circulated from person to person. From this, how can the application of 3D printing technologies explore the infusion of ancient forms with contemporary commentaries to promote discussion? The digital reconstruction of artifacts is a topic that has been researched by various groups all over the globe. Yet, the exploration of Greek myth through artifacts infused with contemporary issues is currently unexplored in this medium. Using the Stratasys J750 3D printer - a multi-material, full-colour 3D printer - a series of coins inspired by ancient Greek currency and myth was created to present commentaries on the adversities surrounding individuals in the LGBT+ community. Using the J750 as the medium for expression allows for complete control and precision of the models to create complex high-resolution iconography. The coins are printed with a hard, translucent material with coloured 3D visuals embedded into the coin to then be viewed in close contact by the audience. These coins as commentaries present an avenue for wider understanding by drawing perspectives not only from sources concerned with the contemporary LGBT+ community but also from sources exploring ancient homosexuality and the perception and regulation of it in antiquity. By displaying what are usually points of contention between anti- and pro-LGBT+ parties, this visual medium opens up a discussion to both parties, suggesting heritage can play a vital interpretative role in the contemporary world.

Keywords: 3D printing, design, Greek mythology, LGBT+ community

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Authors: Yongde Xia, Laicong Deng, Zhuxian Yang

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Developing cost-effective electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is vital in energy conversion and storage applications. Herein, we report a simple method for the synthesis of graphene-reinforced cobalt sulfide/carbon nanocomposites and the evaluation of their electrocatalytic performance for typical electrocatalytic reactions. Nanocomposites of cobalt sulfide embedded in N, S co-doped porous carbon and graphene (CoS@C/Graphene) were generated via simultaneous sulfurization and carbonization of one-pot synthesized graphite oxide-ZIF-67 precursors. The obtained CoS@C/Graphene nanocomposite was characterized by X-ray diffraction, Raman spectroscopy, Thermogravimetric analysis-Mass spectroscopy, Scanning electronic microscopy, Transmission electronic microscopy, X-ray photoelectron spectroscopy and gas sorption. It was found that cobalt sulfide nanoparticles were homogenously dispersed in the in-situ formed N, S co-doped porous carbon/Graphene matrix. The CoS@C/10Graphene composite not only shows excellent electrocatalytic activity toward ORR with high onset potential of 0.89 V, four-electron pathway and superior durability of maintaining 98% current after continuously running for around 5 hours, but also exhibits good performance for OER and HER, due to the improved electrical conductivity, increased catalytic active sites and connectivity between the electrocatalytic active cobalt sulfide and the carbon matrix. This work offers a new approach for the development of novel multifunctional nanocomposites for the next generation of energy conversion and storage applications.

Keywords: MOF derivative, graphene, electrocatalyst, oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction

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Authors: Sushila Jaiswal, Awadhesh Kumar Jaiswal

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Background: Primary melanocytic tumors of the central nervous system (CNS) are uncommon lesions and arise from the melanocytes located within the leptomeninges. Aim and objective: The aim of the study was to evaluate the clinical details, histomorphology of the primary melanocytic tumor of CNS. Method: The study was performed by the retrospective review of the case records of the primary melanocytic tumors of CNS diagnosed in our department. The formalin-fixed, paraffin embedded tissue blocks and tissue sections were retrieved and reviewed. Results: Seven cases (6 males, 1 female; age range- 16-40 years; mean age- 27 years) of primary melanocytic tumors of CNS were retrieved over last seven years. The tumor was intracranial (n=5; frontal – 1 case, parietal – 1 case, cerebello-pontine angle- 1 case, occipital -1 case, foramen magnum-1 case) and intra spinal (n=2; cervical – 2 cases). All patients presented with the neurological deficits related to the location of the tumor. Four cases were malignant melanoma; two were melanocytoma of intermediate grade and remaining one was melanocytoma. On histopathology, melanocytoma and melanoma both displayed sheets of well-differentiated melanocytes having round to oval nuclei with finely dispersed chromatin, occasional single eosinophilic nucleoli and a moderate amount of cytoplasm with abundant granular melanin pigment. The absence of mitosis and macronucleoli was noticed in melanocytoma while melanoma showed frequent mitosis and macronucleoli. On immunohistochemistry, both showed diffuse strong HMB45 and S-100 immunopositivity. Conclusion: Primary melanocytic tumors of CNS are rare and predominantly seen in males. It is important to differentiate melanoma from melanocytoma as prognosis of later is good.

Keywords: melanocytoma, melanoma, brain tumor, melanin

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Authors: Parisi L., Hamili D., Azlan N.

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The aim of this study was to design and simulate a particular type of Asynchronous State Machine (ASM), namely a ‘traffic light controller’ (TLC), operated at a frequency of 0.5 Hz. The design task involved two main stages: firstly, designing a 4-bit binary counter using J-K flip flops as the timing signal and subsequently, attaining the digital logic by deploying ASM design process. The TLC was designed such that it showed a sequence of three different colours, i.e. red, yellow and green, corresponding to set thresholds by deploying the least number of AND, OR and NOT gates possible. The software Multisim was deployed to design such circuit and simulate it for circuit troubleshooting in order for it to display the output sequence of the three different colours on the traffic light in the correct order. A clock signal, an asynchronous 4-bit binary counter that was designed through the use of J-K flip flops along with an ASM were used to complete this sequence, which was programmed to be repeated indefinitely. Eventually, the circuit was debugged and optimized, thus displaying the correct waveforms of the three outputs through the logic analyzer. However, hazards occurred when the frequency was increased to 10 MHz. This was attributed to delays in the feedback being too high.

Keywords: asynchronous state machine, traffic light controller, circuit design, digital electronics

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Authors: Sandhya Rao

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Kevin Lynch’s Theory on Imeageability, let on explore a city in terms of five elements, Nodes, Paths, Edges, landmarks and Districts. What happens when we try to record the same data in an Indian context? What happens when we apply the same theory of Imageability to a complex shifting urban pattern of the Indian cities and how can we as Urban Designers demonstrate our role in the image building ordeal of these cities? The organizational patterns formed through mental images, of an Indian city is often diverse and intangible. It is also multi layered and temporary in terms of the spirit of the place. The pattern of images formed is loaded with associative meaning and intrinsically linked with the history and socio-cultural dominance of the place. The embedded memory of a place in one’s mind often plays an even more important role while formulating these images. Thus while deriving an image of a city one is often confused or finds the result chaotic. The images formed due to its complexity are further difficult to represent using a single medium. Under such a scenario it’s difficult to derive an output of an image constructed as well as make design interventions to enhance the legibility of a place. However, there can be a combination of tools and methods that allows one to record the key elements of a place through time, space and one’s user interface with the place. There has to be a clear understanding of the participant groups of a place and their time and period of engagement with the place as well. How we can translate the result obtained into a design intervention at the end, is the main of the research. Could a multi-faceted cognitive mapping be an answer to this or could it be a very transient mapping method which can change over time, place and person. How does the context influence the process of image building in one’s mind? These are the key questions that this research will aim to answer.

Keywords: imageability, organizational patterns, legibility, cognitive mapping

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Authors: Schnell Zsuzsanna

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Background: The interpretation of written texts, language processing in the visual domain, in other words, atypical reading abilities, also known as dyslexia, is an ever-growing phenomenon in today’s societies and educational communities. The much-researched problem affects cognitive abilities and, coupled with normal intelligence normally manifests difficulties in the differentiation of sounds and orthography and in the holistic processing of written words. The factors of susceptibility are varied: social, cognitive psychological, and linguistic factors interact with each other. Methods: The research will explain the psycholinguistics of dyslexia on the basis of several empirical experiments and demonstrate how domain-general abilities of inhibition, retrieval from the mental lexicon, priming, phonological processing, and visual modality transfer affect successful language processing and interpretation. Interpretation of visual stimuli is hindered, and the problem seems to be embedded in a sociocultural, psycholinguistic, and cognitive background. This makes the picture even more complex, suggesting that the understanding and resolving of the issues of dyslexia has to be interdisciplinary, aided by several disciplines in the field of humanities and social sciences, and should be researched from an empirical approach, where the practical, educational corollaries can be analyzed on an applied basis. Aim and applicability: The lecture sheds light on the applied, cognitive aspects of interpretation, social cognitive traits of language processing, the mental underpinnings of cognitive interpretation strategies in different languages (namely, Hungarian and English), offering solutions with a few applied techniques for success in foreign language learning that can be useful advice for the developers of testing methodologies and measures across ESL teaching and testing platforms.

Keywords: dyslexia, social cognition, transparency, modalities

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Authors: Andrey V. Osipov, Sergey A. Kukushkin, Andrey V. Luk’yanov

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A method is developed for the solid-phase synthesis of epitaxial layers when the substrate itself is involved into a topochemical reaction and the reaction product grows in the interior of substrate layer. It opens up new possibilities for the relaxation of the elastic energy due to the attraction of point defects formed during the topochemical reaction in anisotropic media. The presented method of silicon carbide (SiC) formation employs a topochemical reaction between the single-crystalline silicon (Si) substrate and gaseous carbon monoxide (CO). The corresponding theory of interaction of point dilatation centers in anisotropic crystals is developed. It is eliminated that the most advantageous location of the point defects is the direction (111) in crystals with cubic symmetry. The single-crystal SiC films with the thickness up to 200 nm have been grown on Si (111) substrates owing to the topochemical reaction with CO. Grown high-quality single-crystal SiC films do not contain misfit dislocations despite the huge lattice mismatch value of ~20%. Also the possibility of growing of thick wide-gap semiconductor films on these templates SiC/Si(111) and, accordingly, its integration into Si electronics, is demonstrated. Finally, the ab initio theory of SiC formation due to the topochemical reaction has been developed.

Keywords: epitaxy, silicon carbide, topochemical reaction, wide-bandgap semiconductors

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Authors: Zhaopeng Zhu, Xianzhi Song, Gensheng Li, Shuo Zhu, Shiming Duan, Xuezhe Yao

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Accurate calculation of wellbore pressure is of great significance to prevent wellbore risk during drilling. The traditional mechanism model needs a lot of iterative solving procedures in the calculation process, which reduces the calculation efficiency and is difficult to meet the demand of dynamic control of wellbore pressure. In recent years, many scholars have introduced artificial intelligence algorithms into wellbore pressure calculation, which significantly improves the calculation efficiency and accuracy of wellbore pressure. However, due to the ‘black box’ property of intelligent algorithm, the existing intelligent calculation model of wellbore pressure is difficult to play a role outside the scope of training data and overreacts to data noise, often resulting in abnormal calculation results. In this study, the multi-phase flow mechanism is embedded into the objective function of the neural network model as a constraint condition, and an intelligent prediction model of wellbore pressure under the constraint condition is established based on more than 400,000 sets of pressure measurement while drilling (MPD) data. The constraint of the multi-phase flow mechanism makes the prediction results of the neural network model more consistent with the distribution law of wellbore pressure, which overcomes the black-box attribute of the neural network model to some extent. The main performance is that the accuracy of the independent test data set is further improved, and the abnormal calculation values basically disappear. This method is a prediction method driven by MPD data and multi-phase flow mechanism, and it is the main way to predict wellbore pressure accurately and efficiently in the future.

Keywords: multiphase flow mechanism, pressure while drilling data, wellbore pressure, mechanism constraints, combined drive

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Authors: Kaddari Faiza, Mazari Benyounes, Mihoub Youcef, Safa Ahmed

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Active filtering of electric power has now become a mature technology for reactive power and harmonic compensation caused by the proliferation of power electronics devices used for industrial, commercial and residential purposes. The aim of this study is to enhance the power quality by improving the performances of shunt active power filter in harmonic mitigation to obtain sinusoidal source currents with very weak ripples. A power circuit configuration and control scheme for shunt active power filter are described with an improved method for harmonics compensation using self-tuning-filter for harmonics identification and fuzzy logic control to generate reference current. Simulation results (using MATLAB/SIMULINK) illustrates the compensation characteristics of the proposed control strategy. Analysis of these results proves the feasibility and effectiveness of this method to improve the power quality and also show the performances of fuzzy logic control which provides flexibility, high precision and fast response. The total harmonic distortion (THD %) for the simulations found to be within the recommended imposed IEEE 519-1992 harmonic standard.

Keywords: Active Powers Filter (APF), Self-Tuning-Filter (STF), fuzzy logic control, hysteresis-band control

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Authors: Faizah Almalki, Simeon Gill, Steve G. Hayes, Lisa Taylor

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A core element of cultural identity is the traditional costumes that provide insight into the heritage that has been acquired over time. This heritage is apparent in the use of colour, the styles and the functions of the clothing and it also reflects the skills of those who created the items and the time taken to produce them. Modern flat pattern drafting methods for making garment patterns are simple in comparison to the relatively laborious traditional approaches that would require personal interaction with the wearer throughout the production process. The current study reflects on the main elements of the pattern cutting system and how this has evolved in Saudi Arabia to affect the design of the Sawan garment. Analysis of the traditional methods for constructing Sawan garments was undertaken through observation of the practice and the garments and consulting documented guidance. This provided a foundation through which to explore how modern technology can be applied to improve the process. In this research, modern methods are proposed for producing traditional Saudi garments more efficiently while retaining elements of the conventional style and design. The current study has documented the vital aspects of Sawan garment style. The result showed that the method had been used to take the body measurements and pattern making was elementary and offered simple geometric shape and the Sawan garment is composed of four pieces. Consequently, this research allows for classical pattern shapes to be embedded in garments now worn in Saudi Arabia and for the continuation of cultural heritage.

Keywords: traditional Sawan garment technique, modern pattern cutting technique, the shape of the garment and software, Lectra Modaris

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Authors: Hussein M. Elmehdi

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In this paper, we present the results of our recent experiments done to examine the effect of air bubbles, which were introduced to bio-samples during preparation, on the rheological properties of soft biological materials. To effectively achieve this, we three samples each prepared with differently. Our soft biological systems comprised of three types of flour dough systems made from different flour varieties with variable protein concentrations. The samples were investigated using ultrasonic waves operated at low frequency in transmission mode. The sample investigated included dough made from bread flour, wheat flour and all-purpose flour. During mixing, the main ingredient of the samples (the flour) was transformed into cohesive dough comprised of the continuous dough matrix and air pebbles. The rheological properties of such materials determine the quality of the end cereal product. Two ultrasonic parameters, the longitudinal velocity and attenuation coefficient were found to be very sensitive to properties such as the size of the occluded bubbles, and hence have great potential of providing quantitative evaluation of the properties of such materials. The results showed that the magnitudes of the ultrasonic velocity and attenuation coefficient peaked at optimum mixing times; the latter of which is taken as an indication of the end of the mixing process. There was an agreement between the results obtained by conventional rheology and ultrasound measurements, thus showing the potential of the use of ultrasound as an on-line quality control technique for dough-based products. The results of this work are explained with respect to the molecular changes occurring in the dough system as the mixing process proceeds; particular emphasis is placed on the presence of free water and bound water.

Keywords: ultrasound, soft biological materials, velocity, attenuation

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Authors: Alberto Fina, Samuele Colonna, Maria del Mar Bernal, Orietta Monticelli, Mauro Tortello, Renato Gonnelli, Julio Gomez, Chiara Novara, Guido Saracco

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Thermally conductive polymer nanocomposites are of high interest for several applications including low-temperature heat recovery, heat exchangers in a corrosive environment and heat management in electronics and flexible electronics. In this paper, the preparation of thermally conductive nanocomposites exploiting graphene-related materials is addressed, along with their thermal characterization. In particular, correlations between 1- chemical and physical features of the nanoflakes and 2- processing conditions with the heat conduction properties of nanocomposites is studied. Polymers are heat insulators; therefore, the inclusion of conductive particles is the typical solution to obtain a sufficient thermal conductivity. In addition to traditional microparticles such as graphite and ceramics, several nanoparticles have been proposed, including carbon nanotubes and graphene, for the use in polymer nanocomposites. Indeed, thermal conductivities for both carbon nanotubes and graphenes were reported in the wide range of about 1500 to 6000 W/mK, despite such property may decrease dramatically as a function of the size, number of layers, the density of topological defects, re-hybridization defects as well as on the presence of impurities. Different synthetic techniques have been developed, including mechanical cleavage of graphite, epitaxial growth on SiC, chemical vapor deposition, and liquid phase exfoliation. However, the industrial scale-up of graphene, defined as an individual, single-atom-thick sheet of hexagonally arranged sp2-bonded carbons still remains very challenging. For large scale bulk applications in polymer nanocomposites, some graphene-related materials such as multilayer graphenes (MLG), reduced graphene oxide (rGO) or graphite nanoplatelets (GNP) are currently the most interesting graphene-based materials. In this paper, different types of graphene-related materials were characterized for their chemical/physical as well as for thermal properties of individual flakes. Two selected rGOs were annealed at 1700°C in vacuum for 1 h to reduce defectiveness of the carbon structure. Thermal conductivity increase of individual GNP with annealing was assessed via scanning thermal microscopy. Graphene nano papers were prepared from both conventional RGO and annealed RGO flakes. Characterization of the nanopapers evidenced a five-fold increase in the thermal diffusivity on the nano paper plane for annealed nanoflakes, compared to pristine ones, demonstrating the importance of structural defectiveness reduction to maximize the heat dissipation performance. Both pristine and annealed RGO were used to prepare polymer nanocomposites, by melt reactive extrusion. Thermal conductivity showed two- to three-fold increase in the thermal conductivity of the nanocomposite was observed for high temperature treated RGO compared to untreated RGO, evidencing the importance of using low defectivity nanoflakes. Furthermore, the study of different processing paremeters (time, temperature, shear rate) during the preparation of poly (butylene terephthalate) nanocomposites evidenced a clear correlation with the dispersion and fragmentation of the GNP nanoflakes; which in turn affected the thermal conductivity performance. Thermal conductivity of about 1.7 W/mK, i.e. one order of magnitude higher than for pristine polymer, was obtained with 10%wt of annealed GNPs, which is in line with state of the art nanocomposites prepared by more complex and less upscalable in situ polymerization processes.

Keywords: graphene, graphene-related materials, scanning thermal microscopy, thermally conductive polymer nanocomposites

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Authors: Terence Lucero F. Menor, Manolo G. Mena, Herman D. Mendoza

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Solder pastes are widely used in creating mechanical, thermal and electrical connection between electronic components. Continued miniaturization of consumer electronics drives manufacturers to achieve smaller, lighter, and faster electronic packages at low cost. This faces them to the difficult challenge of dispensing solder pastes in extremely precise and repeatable manner. The most common problem in solder paste dispensing is the clogging of dispensers which results from agglomeration and settling of solder powders leading to increase on the effective particle size and uneven distribution of particles in the mixture. In this work, microelectrophoresis was employed to investigate the effect of pH and KNO₃ concentration on the electrokinetic behavior and stability of SAC305, PbSn5Ag2.5 and Sn powders in aqueous media. Results revealed that the electrokinetic behavior of the three types of solder powders are similar, which was attributed to high SnO₂ content on the surface of the particles. Electrokinetic measurements showed that the zeta potentials of the solder powders are highly dependent on pH and KNO₃ concentration with isoelectric points ranging from 3.5 to 5.5. Results were verified using stability tests.

Keywords: electrokinetic behavior, isoelectric point, solder powder, stability, surface analysis

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Authors: Ehsan Alishahi, Chuang Deng

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Commercial applications of bulk metallic glasses (BMGs) were restricted due to the sudden brittle failure mode which was the main drawback in these new class of materials. Therefore, crystalline-amorphous (C-A) composites were introduced as a toughening strategy in BMGs. In spite of numerous researches in the area of metallic C-A composites, the fundamental structure-property relation in these composites that are not exactly known yet. In this study, it is aimed to investigate the fundamental properties of crystalline-amorphous interface in a model system of Cu/CuZr by using molecular dynamics simulations. Several parameters including interface energy and mechanical properties were investigated by means of atomic models and employing Embedded Atom Method (EAM) potential function. It is found that the crystalline-amorphous interfacial energy weakly depends on the orientation of the crystalline layer, which is in stark contrast to that in a regular crystalline grain boundary. Additionally, the results showed that the interface controls the yielding of the crystalline-amorphous composites during uniaxial tension either by serving as sources for dislocation nucleation in the crystalline layer or triggering local shear transformation zones in amorphous layer. The critical resolved shear stress required to nucleate the first dislocation is also found to strongly depend on the crystalline orientation. Furthermore, it is found that the interaction between dislocations and shear localization at the crystalline-amorphous interface oriented in different directions can lead to a change in the deformation mode. For instance, while the dislocation and shear banding are aligned to each other in {0 0 1} interface plane, the misorientation angle between these failure mechanisms causing more homogeneous deformation in {1 1 0} and {1 1 1} crystalline-amorphous interfaces. These results should help clarify the failure mechanism of crystalline-amorphous composites under various loading conditions.

Keywords: crystalline-amorphous, composites, orientation, plasticity

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Authors: Chukwuma Mgboji

Abstract:

Since the advent of Artificial Intelligence, robots have become a major stay in developing societies. Robots are deployed in Education, Health, Food and in other spheres of life. Nigeria a country in West Africa has a very low profile in the advancement of Artificial Intelligence especially in the grass roots. The benefits of Artificial intelligence are not fully maximised and harnessed. Advances in artificial intelligence are perceived as impossible or observed as irrelevant. This study seeks to ascertain the needed skills for the development of artificialintelligence amongst secondary schools in Nigeria. The study focused on South East Nigeria with Five states namely Imo, Abia, Ebonyi, Anambra and Enugu. The sample size is 1000 students drawn from Five Government owned Universities offering Computer Science, Computer Education, Electronics Engineering across the Five South East states. Survey method was used to solicit responses from respondents. The findings from the study identified mathematical skills, analytical skills, problem solving skills, computing skills, programming skills, algorithm skills amongst others. The result of this study to the best of the author’s knowledge will be highly beneficial to all stakeholders involved in the advancements and development of artificial intelligence.

Keywords: artificial intelligence, secondary school, robotics, skills

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Authors: M. Nagaraja, H. M. Mahesh, K. Rajanna, M. Z. Kurian, J. Manjanna

Abstract:

In recent years, composites of conjugated polymers with fullerenes (C60) has attracted considerable scientific and technological attention in the field of organic electronics because they possess a novel combination of electrical, optical, ferromagnetic, mechanical and sensor properties. These properties represent major advances in the design of organic electronic devices. With the addition of C60 in the conjugated polymer matrix, the primary photo-excitation of the conjugated polymer undergoes an ultrafast electron transfer, and it has been demonstrated that fullerene molecules may serve as efficient electron acceptors in polymeric solar cells. The present paper includes the systematic studies on the effect of electrical, structural and sensor properties of polyaniline (PANI) matrix by the presence of C60. Polyaniline-fullerene (PANI/C60) composite is prepared by the introduction of fullerene during polymerization of aniline with ammonium persulfate and dodechyl benzene sulfonic acid as oxidant and dopant respectively. FTIR spectroscopy indicated the interaction between PANI and C60. X-ray diffraction proved the formation of a PANI/C60 complex. SEM image shows the highly branched chain structure of the PANI in the presence of C60. The conductivity of the PANI/C60 was found to be more than ten orders of magnitude over the pure PANI.

Keywords: conductivity, fullerene, nanocomposite, polyaniline

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Authors: M. A. Lawal, A. Uzairu, M. S. Sallau

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The presence and bioaccumulation of lead (Pb), cadmium (Cd), and chromium (Cr) in blood, urine, nail, and hair samples of electronic repair technicians in Kaduna-Nigeria were assessed using Fast Sequential Atomic Absorption Spectrophotometry. 10 electronic repair technicians from within Kaduna Metropolis volunteered for the pilot study. The mean blood concentrations of Pb, Cd, and Cr in the subjects were 29.33 ± 4.80, 7.78 ± 10.57, and 24.78 ± 21.77 µg/dL, respectively. The mean urine concentrations of Pb, Cd, and Cr were 24.18 ± 2.98, 6.81 ± 10.05, and 14.78 ± 14.20 µg/dL, respectively. Mean nail metal values of 37.13 ± 4.08, 1.00 ± 1.21, and 18.49 ± 12.71 µg/g were obtained for Pb, Cd, and Cr, respectively while mean hair metal values of 39.41 ± 5.63, 1.09 ± 1.14, and 19.13 ± 11.61 µg/g for Pb, Cd, and Cr, respectively. Positive Pearson correlation coefficients were observed between Pb/Cd, Pb/Cr, and Cd/Cr in all samples and they indicate the metals are likely from the same pollution source. The mean concentrations of the metals in all samples were higher than the WHO, ILO, and ACGIH standards, implying the repairers are likely occupationally exposed and are subject to serious health concerns. Social habits like smoking were found to significantly affect the concentrations of these metals. The level of education, use of safety devices, period of exposure, the nature of electronics and the age of the repairers were also found to remarkably affect the concentrations of the metals.

Keywords: bioaccumulation, electronic repair technicians, heavy metals, occupational hazard

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Authors: Patikineti Sreenivasulu, K. srinivasa Rao, A. Vinaya Babu

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The demand for portability, performance and high functional integration density of digital devices leads to the scaling of complementary metal oxide semiconductor (CMOS) devices inevitable. The increase in power consumption, coupled with the increasing demand for portable/hand-held electronics, has made power consumption a dominant concern in the design of VLSI circuits today. MTCMOS technology provides low leakage and high performance operation by utilizing high speed, low Vt (LVT) transistors for logic cells and low leakage, high Vt (HVT) devices as sleep transistors. Sleep transistors disconnect logic cells from the supply and/or ground to reduce the leakage in the sleep mode. In this technology, energy consumption while doing the mode transition and minimum time required to turn ON the circuit upon receiving the wake up signal are issues to be considered because these can adversely impact the performance of VLSI circuit. In this paper we are introducing an enhancing method of MTCMOS technology to optimize the power in MTCMOS sequential circuits.

Keywords: power consumption, ultra-low power, leakage, sub threshold, MTCMOS

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Authors: Behrang Tavousi Tehrani, Mohammad-Zaman Kabir

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Shape memory alloys (SMA) are often implemented in smart structures as the active components. Their ability to recover large displacements has been used in many applications, including structural stability/response enhancement and active structural acoustic control. SMA wires or fibers can be embedded with composite cylinders to increase their critical buckling load, improve their load-deflection behavior, and reduce the radial deflections under various thermo-mechanical loadings. This paper presents a semi-analytical investigation on the non-linear load-deflection response of SMA-reinforced composite circular cylindrical shells. The cylinder shells are under uniform external pressure load. Based on first-order shear deformation shell theory (FSDT), the equilibrium equations of the structure are derived. One-dimensional simplified Brinson’s model is used for determining the SMA recovery force due to its simplicity and accuracy. Airy stress function and Galerkin technique are used to obtain non-linear load-deflection curves. The results are verified by comparing them with those in the literature. Several parametric studies are conducted in order to investigate the effect of SMA volume fraction, SMA pre-strain value, and SMA activation temperature on the response of the structure. It is shown that suitable usage of SMA wires results in a considerable enhancement in the load-deflection response of the shell due to the generation of the SMA tensile recovery force.

Keywords: airy stress function, cylindrical shell, Galerkin technique, load-deflection curve, recovery stress, shape memory alloy

Procedia PDF Downloads 186

Authors: Stefano M. Spagocci

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The efficiency of photovoltaic panels can be calculated with such software packages as RETScreen that allow design engineers to take financial as well as technical considerations into account. RETScreen is interfaced with meteorological databases, so that efficiency calculations can be realistically carried out. The author has recently contributed to the development of solar modules with accumulation capability and an embedded water purifier, aimed at off-grid users such as users in developing countries. The software packages examined do not allow to take ancillary equipment into account, hence the decision to implement a technical and financial model of the system. The author realized that, rather than re-implementing the quite sophisticated model of RETScreen - a mathematical description of which is anyway not publicly available - it was possible to drastically simplify it, including the meteorological factors which, in RETScreen, are presented in a numerical form. The day-by-day efficiency of a photovoltaic solar panel was parametrized by the product of factors expressing, respectively, daytime duration, solar right ascension motion, solar declination motion, cloudiness, temperature. For the sun-motion-dependent factors, positional astronomy formulae, simplified by the author, were employed. Meteorology-dependent factors were fitted by simple trigonometric functions, employing numerical data supplied by RETScreen. The accuracy of our model was tested by comparing it to the predictions of RETScreen; the accuracy obtained was 11%. In conclusion, our study resulted in a model that can be easily implemented in a spreadsheet - thus being easily manageable by non-specialist personnel - or in more sophisticated software packages. The model was used in a number of design exercises, concerning photovoltaic solar panels and ancillary equipment like the above-mentioned water purifier.

Keywords: clean energy, energy engineering, mathematical modelling, photovoltaic panels, solar energy

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Authors: Hrishikesh Purandare, Ashwini Pethe

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Research from developed countries has demonstrated that the built environment can have a significant effect on children’s cognitive and socio-emotional development. A majority of the studies on the relationship between the built environment and the well-being of children have been conducted in North America and Western Europe, though most of the world’s children live in the global South. Millions of children living in urban slums in India confront issues associated with poor living conditions and lack of access to basic services. It is a well-known fact that slums are places of extreme poverty, substandard housing, overcrowding, and poor sanitation. These challenges faced by children living in slums can have a significant impact on their physical, psychological, and social development. Despite the magnitude of the problem, the area of research, particularly on the impact of the built environment of slums on children and adolescent well-being, has been understudied in India. Only a few studies in the global South have investigated the impact of the built environment on children’s well-being. Apart from issues of the limited access to health and education of these children, the perception of children regarding the built environment which they inhabit is rarely addressed. A sample of 120 children living in the slums of Pune city between the ages 7 and 16 participated in this study, which employed a concurrent embedded approach of mixed method research. Questionnaires were administered to obtain quantitative data that included attributes of crowding, noise, privacy, territoriality and housing quality in the built environment. The qualitative analysis of children’s sketches highlighted aspects of the built environment with which they associated themselves the most. The study sought to examine the perception of the deprived children living in the urban slums in the city of Pune (India) towards their built environment.

Keywords: physical environment, poverty, underprivileged children, urban Indian slums

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Authors: Sultan Alharby, Nick Harris, Alex Weddell, Jeff Reeve

Abstract:

The concept of the Internet of Things (IoT) has received much attention over the last five years. It is predicted that the IoT will influence every aspect of our lifestyles in the near future. Wireless Sensor Networks are one of the key enablers of the operation of IoTs, allowing data to be collected from the surrounding environment. However, due to limited resources, nature of deployment and unattended operation, a WSN is vulnerable to various types of attack. Security is paramount for reliable and safe communication between IoT embedded devices, but it does, however, come at a cost to resources. Nodes are usually equipped with small batteries, which makes energy conservation crucial to IoT devices. Nevertheless, security cost in terms of energy consumption has not been studied sufficiently. Previous research has used a security specification of 802.15.4 for IoT applications, but the energy cost of each security level and the impact on quality of services (QoS) parameters remain unknown. This research focuses on the cost of security at the IoT media access control (MAC) layer. It begins by studying the energy consumption of IEEE 802.15.4 security levels, which is followed by an evaluation for the impact of security on data latency and throughput, and then presents the impact of transmission power on security overhead, and finally shows the effects of security on memory footprint. The results show that security overhead in terms of energy consumption with a payload of 24 bytes fluctuates between 31.5% at minimum level over non-secure packets and 60.4% at the top security level of 802.15.4 security specification. Also, it shows that security cost has less impact at longer packet lengths, and more with smaller packet size. In addition, the results depicts a significant impact on data latency and throughput. Overall, maximum authentication length decreases throughput by almost 53%, and encryption and authentication together by almost 62%.

Keywords: energy consumption, IEEE 802.15.4, IoT security, security cost evaluation

Procedia PDF Downloads 162