Search results for: high tech

Authors: Kobamelo Mashaba

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The molten slag has a high substantial temperatures range between 1723-1923, carrying a huge amount of useful energy for reducing energy consumption and CO₂ emissions under the heat recovery process. Therefore in this study, we investigated the performance of the modified crank Nicolson method for a delayed partial differential equation on the heat recovery of molten slag in the metallurgical mining environment. It was proved that the proposed method converges quickly compared to the classic method with the existence of a unique solution. It was inferred from numerical result that the proposed methodology is more viable and profitable for the mining industry.

Keywords: delayed partial differential equation, modified Crank-Nicolson Method, molten slag, heat recovery, parabolic equation

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Authors: Abdeljalil Metioui

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The purpose of this article is to present the results of two-stage qualitative research. The first involved the identification of the alternative conceptions of 80 elementary pre-service teachers from Quebec in Canada about the operation of simple electrical circuits. To do this, they completed a two-choice questionnaire (true or false) with justification. Data analysis identifies many conceptual difficulties. For example, for their majority, whatever the electrical device that composes an electrical circuit, the current source (power supply), and the generated electrical power is constant. The second step was to develop a double multiple-choice questionnaire based on the identified designs. It allows teachers to quickly diagnose their students' conceptions and take them into account in their teaching.

Keywords: development, electrical circuits, two-tier diagnostic test, secondary and high school

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Authors: Mohammadreza Biabani, Mohammad Azadfallah

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A facile and robust strategy is required to fabricate films with high special optical properties for application in the field of anti-counterfeit marking. Nanocellulose, derived from bioresources, is a renewable material with broad application prospects. In this paper, a method for grafting the eco-friendly Berberine cationic dye on cellulose nanofiber is proposed. A functional modification was carried out by in-situ polymerization along with a grafting approach with acrylic acid(AA) in order to develop cationic dyeability of the cellulose nanofiber (CNF). The Berberine grafting on nanocellulose was significantly influenced by the reaction time and temperature during the dyeing process. The dyed CNF-films exhibited appropriate characteristics like appearance, color strength, and fastness for anti-counterfeiting application.

Keywords: Cellulose nanofiber, Berberine, Grafting, anti-counterfeiting, film

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Authors: Lami Mohammed, Hussain J. Al Faifi, Abdel Aziz Al Bassam, Osama M. K. Kassem

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The Neoproterozoic basement rocks of the Ar Rayn terrane have been identified as parts of the Eastern Arabian Shield. It focuses on the petrological and finite strain properties to display the tectonic setting of the Al Amar suture for high deformed volcanic and granitoids rocks. The volcanic rocks are classified into two major series: the eastern side cycle, which includes dacite, rhyodacite, rhyolite, and ignimbrites, and the western side cycle, which includes andesite and pyroclastics. Granitoids rocks also contain monzodiorite, tonalite, granodiorite, and alkali-feldspar granite. To evaluate the proportions of shear contributions in penetratively deformed rocks. Asymmetrical porphyroclast and sigmoidal structural markers along the suture's strike, namely the Al Amar, are expected to reveal strain factors. The Rf/phi and Fry techniques are used to characterize quartz and feldspar porphyroclast, biotite, and hornblende grains in Abt schist, high deformed volcanic rock, and granitoids. The findings exposed that these rocks had experienced shape flattening, finite strain accumulation, and overall volume loss. The magnitude of the strain appears to increase across the nappe contacts with neighboring lithologies. Subhorizontal foliation likely developed in tandem with thrusting and nappe stacking, almost parallel to tectonic contacts. The ductile strain accumulation that occurred during thrusting along the Al Amar suture mostly includes a considerable pure shear component. Progressive thrusting by overlaid transpression and oblique convergence is shown by stacked nappes and diagonal stretching lineations along the thrust axes. The subhorizontal lineation might be the result of the suture's most recent activity. The current study's findings contradict the widely accepted model that links orogen-scale structures in the Arabian Shield to oblique convergence with dominant simple shear deformation. A significant pure shear component/crustal thickening increment should have played a significant role in the evolution of the suture and thus in the Shield's overall deformation history. This foliation was primarily generated by thrusting nappes together, showing that nappe stacking was linked to substantial vertical shortening induced by the active Al Amar suture on a massive scale.

Keywords: petrology, finite strain analysis, al amar region, ar-rayn terrane, Arabian shield

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Authors: Hooman Torabifard

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In the last few years, with the progress of technology and computers and artificial intelligence entry into all kinds of scientific and industrial fields, the lifestyles of human life have changed and in general, the way of humans live on earth has many changes and development. Until now, some of the changes has occurred in the context of digital images and image processing and still continues. However, besides all the benefits, there have been disadvantages. One of these disadvantages is the multiplicity of images with high volume and data; the focus of this paper is on improving and developing a method for summarizing and enhancing the productivity of these images. The general method used for this purpose in this paper consists of a set of methods based on data obtained from image processing and using the PSO (Particle swarm optimization) algorithm. In the remainder of this paper, the method used is elaborated in detail.

Keywords: image summarization, particle swarm optimization, image threshold, image processing

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Authors: Amit Kumar Verma

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The present study deals with fire prediction model in Terai Arc Landscape, one of the most dramatic ecosystems in Asia where large, wide-ranging species such as tiger, rhinos, and elephant will thrive while bringing economic benefits to the local people. Forest fires cause huge economic and ecological losses and release considerable quantities of carbon into the air and is an important factor inflating the global burden of carbon emissions. Forest fire is an important factor of behavioral cum ecological habit of tiger in wild. Post fire changes i.e. micro and macro habitat directly affect the tiger habitat or land. Vulnerability of fire depicts the changes in microhabitat (humus, soil profile, litter, vegetation, grassland ecosystem). Microorganism like spider, annelids, arthropods and other favorable microorganism directly affect by the forest fire and indirectly these entire microorganisms are responsible for the development of tiger (Panthera tigris) habitat. On the other hand, fire brings depletion in prey species and negative movement of tiger from wild to human- dominated areas, which may leads the conflict i.e. dangerous for both tiger & human beings. Early forest fire prediction through mapping the risk zones can help minimize the fire frequency and manage forest fires thereby minimizing losses. Satellite data plays a vital role in identifying and mapping forest fire and recording the frequency with which different vegetation types are affected. Thematic hazard maps have been generated by using IDW technique. A prediction model for fire occurrence is developed for TAL. The fire occurrence records were collected from state forest department from 2000 to 2014. Disciminant function models was used for developing a prediction model for forest fires in TAL, random points for non-occurrence of fire have been generated. Based on the attributes of points of occurrence and non-occurrence, the model developed predicts the fire occurrence. The map of predicted probabilities classified the study area into five classes very high (12.94%), high (23.63%), moderate (25.87%), low(27.46%) and no fire (10.1%) based upon the intensity of hazard. model is able to classify 78.73 percent of points correctly and hence can be used for the purpose with confidence. Overall, also the model works correctly with almost 69% of points. This study exemplifies the usefulness of prediction model of forest fire and offers a more effective way for management of forest fire. Overall, this study depicts the model for conservation of tiger’s natural habitat and forest conservation which is beneficial for the wild and human beings for future prospective.

Keywords: fire prediction model, forest fire hazard, GIS, landsat, MODIS, TAL

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Authors: Sun Il Yu, Jung Hyun Joo, Hwa Sung Shin

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Astrocytes are known as dominant cells in CNS and play a role as a supporter of CNS activity and regeneration. Recently, three-dimensional culture of astrocytes were actively applied to understand in vivo astrocyte works. Electrospun nanofibers are attractive for 3D cell culture system because they have a high surface to volume ratio and porous structure, and have already been used for 3D astrocyte cultures. In this research, the stiffness of cellulose acetate (CA) nanofiber was controlled by heat treatment. As stiffness increased, astrocyte cell viability and adhesion increased. Reactivity of astrocyte was also upregulated in stiffer CA nanofiber in terms of GFAP, an intermediate filament protein. Finally, we demonstrated that stiffness-controllable CA is attractive for astrocyte tissue engineering.

Keywords: astrocyte, cellulose acetate, nanofiber, tissue scaffold

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Authors: Pui Hong Chung, Cyrus Leung, Jun Li, Kin On Kwok, Ek Yeoh

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Introduction: Studies for TB control in intermediate tuberculosis burden countries (IBCs) comprise a relatively small proportion in TB control literature, as compared to the effort put in high and low burden counterparts. It currently lacks of consensus in the optimal weapons and strategies we can use to combat TB in IBCs; guidelines of TB control are inadequate and thus posing a great obstacle in eliminating TB in these countries. To fill-in the research and services gap, we need to summarize the findings of the effort in this regard and to seek consensus in terms of policy making for TB control, we have devised a series of scoping and Delphi studies for these purposes. Method: The scoping and Delphi studies are conducted in parallel to feed information for each other. Before the Delphi iterations, we have invited three local experts in TB control in Hong Kong to participate in the pre-assessment round of the Delphi study to comments on the validity, relevance, and clarity of the Delphi questionnaire. Result: Two scoping studies, regarding LTBI control in health care workers in IBCs and TB control in elderly of IBCs respectively, have been conducted. The result of these two studies is used as the foundation for developing the Delphi questionnaire, which tapped on seven areas of question, namely: characteristics of IBCs, adequacy of research and services in LTBI control in IBCs, importance and feasibility of interventions for TB control and prevention in hospital, screening and treatment of LTBI in community, reasons of refusal to/ default from LTBI treatment, medical adherence of LTBI treatment, and importance and feasibility of interventions for TB control and prevention in elderly in IBCs. The local experts also commented on the two scoping studies conducted, thus act as the sixth phase of expert consultation in Arksey and O’Malley framework of scoping studies, to either nourish the scope and strategies used in these studies or to supplement ideas for further scoping or systematic review studies. In the subsequent stage, an international expert panel, comprised of 15 to 20 experts from IBCs in Western Pacific Region, will be recruited to join the two-round anonymous Delphi iterations. Four categories of TB control experts, namely clinicians, policy makers, microbiologists/ laboratory personnel, and public health clinicians will be our target groups. A consensus level of 80% is used to determine the achievement of consensus on particular issues. Key messages: 1. Scoping review and Delphi method are useful to identify gaps and then achieve consensus in research. 2. Lots of resources are put in the high burden countries now. However, the usually neglected intermediate-burden countries with TB is an indispensable part for achieving the ambitious WHO End TB 2035 target.

Keywords: dephi questionnaire, tuberculosis, WHO, latent TB infection

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Authors: Balarabe Z. Ahmad, Anne-Lorène Vernay

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The emergence of electricity in Nigeria was dated back to 1896. The power plants have the potential to generate 12,522 MW of electric power. Whereas current dispatch is about 4,000 MW, access to electrification is about 60%, with consumption at 0.14 MWh/capita. The government embarked on energy reforms to mitigate energy poverty. The reform targeted the provision of electricity access to 75% of the population by 2020 and 90% by 2030. Growth of total electricity demand by a factor of 5 by 2035 had been projected. This means that Nigeria will require almost 530 TWh of electricity which can be delivered through generators with a capacity of 65 GW. Analogously, the geographical location of Nigeria has placed it in an advantageous position as the source of solar energy; the availability of a high sunshine belt is obvious in the country. The implication is that the far North, where energy poverty is high, equally has about twice the solar radiation as against southern Nigeria. Hence, the chance of generating solar electricity is 66% possible at 11850 x 103 GWh per year, which is one hundred times the current electricity consumption rate in the country. Harvesting these huge potentials may be a mirage if the entrepreneurs in the solar panel business are left with the conventional business models that are not uncertainty resilient. Currently, business entities in RE in Nigeria are uncertain of; accessing the national grid, purchasing potentials of cooperating organizations, currency fluctuation and interest rate increases. Uncertainties such as the security of projects and government policy are issues entrepreneurs must navigate to remain sustainable in the solar panel industry in Nigeria. The aim of this paper is to identify how entrepreneurial firms consider uncertainties in developing workable business models for commercializing solar energy projects in Nigeria. In an attempt to develop a novel business model, the paper investigated how entrepreneurial firms assess and navigate uncertainties. The roles of key stakeholders in helping entrepreneurs to manage uncertainties in the Nigeria RE sector were probed in the ongoing study. The study explored empirical uncertainties that are peculiar to RE entrepreneurs in Nigeria. A mixed-mode of research was embraced using qualitative data from face-to-face interviews conducted on the Solar Energy Entrepreneurs and the experts drawn from key stakeholders. Content analysis of the interview was done using Atlas. It is a nine qualitative tool. The result suggested that all stakeholders are required to synergize in developing an uncertainty resilient business model. It was opined that the RE entrepreneurs need modifications in the business recommendations encapsulated in the energy policy in Nigeria to strengthen their capability in delivering solar energy solutions to the yawning Nigerians.

Keywords: uncertainties, entrepreneurial, business model, solar-panel

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Authors: K. Djellabi, M. E. H. Latreche

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Induction heating computer simulation is a powerful tool for process design and optimization, induction coil design, equipment selection, as well as education and business presentations. The authors share their vast experience in the practical use of computer simulation for different induction heating and heat treating processes. In this paper deals with mathematical modeling and numerical simulation of induction heating furnaces with axisymmetric geometries. For the numerical solution, we propose finite element methods combined with boundary (FEM) for the electromagnetic model using COMSOL® Multiphysics Software. Some numerical results for an industrial furnace are shown with high frequency.

Keywords: numerical methods, induction furnaces, induction heating, finite element method, Comsol multiphysics software

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Authors: Dyah Purwaningsih, Roto Roto, Hari Sutrisno

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Manganese dioxide (MnO₂) and its derivatives are among the most widely used materials for the positive electrode in both primary and rechargeable lithium batteries. The MnO₂ derivative compound of LiMₓMn₂₋ₓO₄ (M: Co, Ni, Cr) is one of the leading candidates for positive electrode materials in lithium batteries as it is abundant, low cost and environmentally friendly. Over the years, synthesis of LiMₓMn₂₋ₓO₄ (M: Co, Ni, Cr) has been carried out using various methods including sol-gel, gas condensation, spray pyrolysis, and ceramics. Problems with these various methods persist including high cost (so commercially inapplicable) and must be done at high temperature (environmentally unfriendly). This research aims to: (1) synthesize LiMₓMn₂₋ₓO₄ (M: Co, Ni, Cr) by reflux technique; (2) develop microstructure analysis method from XRD Powder LiMₓMn₂₋ₓO₄ data with the two-stage method; (3) study the electrical conductivity of LiMₓMn₂₋ₓO₄. This research developed the synthesis of LiMₓMn₂₋ₓO₄ (M: Co, Ni, Cr) with reflux. The materials consisting of Mn(CH₃COOH)₂. 4H₂O and Na₂S₂O₈ were refluxed for 10 hours at 120°C to form β-MnO₂. The doping of Co, Ni and Cr were carried out using solid-state method with LiOH to form LiMₓMn₂₋ₓO₄. The instruments used included XRD, SEM-EDX, XPS, TEM, SAA, TG/DTA, FTIR, LCR meter and eight-channel battery analyzer. Microstructure analysis of LiMₓMn₂₋ₓO₄ was carried out on XRD powder data by two-stage method using FullProf program integrated into WinPlotR and Oscail Program as well as on binding energy data from XPS. The morphology of LiMₓMn₂₋ₓO₄ was studied with SEM-EDX, TEM, and SAA. The thermal stability test was performed with TG/DTA, the electrical conductivity was studied from the LCR meter data. The specific capacity of LiMₓMn₂₋ₓO₄ as lithium battery cathode was tested using an eight-channel battery analyzer. The results showed that the synthesis of LiMₓMn₂₋ₓO₄ (M: Co, Ni, Cr) was successfully carried out by reflux. The optimal temperature of calcination is 750°C. XRD characterization shows that LiMn₂O₄ has a cubic crystal structure with Fd3m space group. By using the CheckCell in the WinPlotr, the increase of Li/Mn mole ratio does not result in changes in the LiMn₂O₄ crystal structure. The doping of Co, Ni and Cr on LiMₓMn₂₋ₓO₄ (x = 0.02; 0.04; 0; 0.6; 0.08; 0.10) does not change the cubic crystal structure of Fd3m. All the formed crystals are polycrystals with the size of 100-450 nm. Characterization of LiMₓMn₂₋ₓO₄ (M: Co, Ni, Cr) microstructure by two-stage method shows the shrinkage of lattice parameter and cell volume. Based on its range of capacitance, the conductivity obtained at LiMₓMn₂₋ₓO₄ (M: Co, Ni, Cr) is an ionic conductivity with varying capacitance. The specific battery capacity at a voltage of 4799.7 mV for LiMn₂O₄; Li₁.₀₈Mn₁.₉₂O₄; LiCo₀.₁Mn₁.₉O₄; LiNi₀.₁Mn₁.₉O₄ and LiCr₀.₁Mn₁.₉O₄ are 88.62 mAh/g; 2.73 mAh/g; 89.39 mAh/g; 85.15 mAh/g; and 1.48 mAh/g respectively.

Keywords: LiMₓMn₂₋ₓO₄, solid-state, reflux, two-stage method, ionic conductivity, specific capacity

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Authors: Meng-Hui Chen, Chen-Yu Kao, Chia-Yu Hsu, Pei-Chann Chang

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The main idea in this paper is using sequential pattern mining to find the information which is helpful for finding high performance solutions. By combining this information, it is defined as blocks. Using the blocks to generate artificial chromosomes (ACs) could improve the structure of solutions. Estimation of Distribution Algorithms (EDAs) is adapted to solve the combinatorial problems. Nevertheless many of these approaches are advantageous for this application, but only some of them are used to enhance the efficiency of application. Generating ACs uses patterns and EDAs could increase the diversity. According to the experimental result, the algorithm which we proposed has a better performance to solve the permutation flow-shop problems.

Keywords: combinatorial problems, sequential pattern mining, estimationof distribution algorithms, artificial chromosomes

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Authors: Azeez Shaik, Yagnik Kalariya, Amit Salvi

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High-performance requirements and emission norms were forcing the automobile industry to opt for lightweight materials which improve the fuel efficiency and absorb energy during crash applications. In such scenario, the woven fabric composites are providing better energy absorption compared to metals. Woven fabric composites have a repetitive unit cell (RUC) and the mechanical properties of these materials are highly dependent on RUC. This work investigates the importance of detailed modelling of the RUC, the size effects associated and the mitigation techniques to avoid them using Finite element analysis approach.

Keywords: repetitive unit cell, representative volume element, size effects, cohesive zone, finite element analysis

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Authors: Hashem Al Argha

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Cerebral Aneurysms are the ballooning and defect that occurs in the arteries of the brain. This ballooning might enlarge in size due to mechanical forces and could lead to rupture and death. Computational Fluid Dynamics has been used in the recent years in creating a link between engineering sciences and medical sciences. In this paper, the effects of mechanical forces on cerebral aneurysms will be studied. Results of this study show that mechanical forces could lead to rupture of the aneurysm and could lead to death. High mechanical forces including stresses up to 1.7 MPa could pop aneurysms and lead to a brain hemorrhage.

Keywords: computational fluid dynamics, numerical, aneurysm, mechanical forces

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Authors: Ahmad Kayvani Fard, Gordon Mckay, Muataz Hussien

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Adsorption/sorption is believed to be one of the optimal processes for the removal of heavy metals from water due to its low operational and capital cost as well as its high removal efficiency. Different materials have been reported in literature as adsorbent for heavy metal removal in waste water such as natural sorbents, organic polymers (synthetic) and mineral materials (inorganic). The selection of adsorbents and development of new functional materials that can achieve good removal of heavy metals from water is an important practice and depends on many factors, such as the availability of the material, cost of material, and material safety and etc. In this study we reported the synthesis of doped Activated carbon and Carbon nanotube (CNT) with different loading of metal oxide nanoparticles such as Fe2O3, Fe3O4, Al2O3, TiO2, SiO2 and Ag nanoparticles and their application in removal of heavy metals, hydrocarbon, and organics from waste water. Commercial AC and CNT with different loadings of mentioned nanoparticle were prepared and effect of pH, adsorbent dosage, sorption kinetic, and concentration effects are studied and optimum condition for removal of heavy metals from water is reported. The prepared composite sorbent is characterized using field emission scanning electron microscopy (FE-SEM), high transmission electron microscopy (HR-TEM), thermogravimetric analysis (TGA), X-ray diffractometer (XRD), the Brunauer, Emmett and Teller (BET) nitrogen adsorption technique, and Zeta potential. The composite materials showed higher removal efficiency and superior adsorption capacity compared to commercially available carbon based adsorbent. The specific surface area of AC increased by 50% reaching up to 2000 m2/g while the CNT specific surface area of CNT increased by more than 8 times reaching value of 890 m2/g. The increased surface area is one of the key parameters along with surface charge of the material determining the removal efficiency and removal efficiency. Moreover, the surface charge density of the impregnated CNT and AC have enhanced significantly where can benefit the adsorption process. The nanoparticles also enhance the catalytic activity of material and reduce the agglomeration and aggregation of material which provides more active site for adsorbing the contaminant from water. Some of the results for treating wastewater includes 100% removal of BTEX, arsenic, strontium, barium, phenolic compounds, and oil from water. The results obtained are promising for the use of AC and CNT loaded with metal oxide nanoparticle in treatment and pretreatment of waste water and produced water before desalination process. Adsorption can be very efficient with low energy consumption and economic feasibility.

Keywords: carbon nanotube, activated carbon, adsorption, heavy metal, water treatment

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Authors: Huda Qari, I. A. Hassan

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The brown alga Padina boryanawas was used for bioassay of polycyclic aromatic hydrocarbons (PAHs) accumulation at the seashore of Jeddah city. PAHs were determined in the coastal water and algal tissues by GC-MS. Acenaphthene (Ace) and dibenzo (a,h) anthracene (dB(a,h)An) were the main PAHs in seawater (50.02 and 46.18) and algal tissues (64.67 and 72.45), respectively. The ratios of low molecular weight/high molecular weight hydrocarbons (1.76 – 1.44), fluoranthene/pyrene (1.57 – 1.52) and phenanthrene/anthracene (0.86 – 0.67) in seawater and algal tissues, respectively, indicated the origin of the PAHs to be mainly petrogenic. This study has demonstrated the utility of using Padina boryanawas as a biomonitor of PAH contamination and bioavailability in the coastal waters.

Keywords: polycyclic aromatic hydrocarbons, Padina boryanawas, bioaccumulation, waste water

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Authors: Zoltan Sebestyen, Eszter Barta-Rajnai, Emma Jakab, Zsuzsanna Czegeny

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Extraction of the energy content of lignocellulosic biomass is one of the possible pathways to reduce the greenhouse gas emission derived from the burning of the fossil fuels. The application of the bioenergy can mitigate the energy dependency of a country from the foreign natural gas and the petroleum. The diversity of the plant materials makes difficult the utilization of the raw biomass in power plants. This problem can be overcome by the application of thermochemical techniques. Pyrolysis is the thermal decomposition of the raw materials under inert atmosphere at high temperatures, which produces pyrolysis gas, biooil and charcoal. The energy content of these products can be exploited by further utilization. The differences in the chemical and physical properties of the raw biomass materials can be reduced by the use of torrefaction. Torrefaction is a promising mild thermal pretreatment method performed at temperatures between 200 and 300 °C in an inert atmosphere. The goal of the pretreatment from a chemical point of view is the removal of water and the acidic groups of hemicelluloses or the whole hemicellulose fraction with minor degradation of cellulose and lignin in the biomass. Thus, the stability of biomass against biodegradation increases, while its energy density increases. The volume of the raw materials decreases so the expenses of the transportation and the storage are reduced as well. Biooil is the major product during pyrolysis and an important by-product during torrefaction of biomass. The composition of biooil mostly depends on the quality of the raw materials and the applied temperature. In this work, thermoanalytical techniques have been used to study the qualitative and quantitative composition of the pyrolysis and torrefaction oils of a woody (black locust) and two herbaceous samples (rape straw and wheat straw). The biooil contains C5 and C6 anhydrosugar molecules, as well as aromatic compounds originating from hemicellulose, cellulose, and lignin, respectively. In this study, special emphasis was placed on the formation of the lignin monomeric products. The structure of the lignin fraction is different in the wood and in the herbaceous plants. According to the thermoanalytical studies the decomposition of lignin starts above 200 °C and ends at about 500 °C. The lignin monomers are present among the components of the torrefaction oil even at relatively low temperatures. We established that the concentration and the composition of the lignin products vary significantly with the applied temperature indicating that different decomposition mechanisms dominate at low and high temperatures. The evolutions of decomposition products as well as the thermal stability of the samples were measured by thermogravimetry/mass spectrometry (TG/MS). The differences in the structure of the lignin products of woody and herbaceous samples were characterized by the method of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). As a statistical method, principal component analysis (PCA) has been used to find correlation between the composition of lignin products of the biooil and the applied temperatures.

Keywords: pyrolysis, torrefaction, biooil, lignin

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Authors: Chua Lee Chuan

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This study was conducted to explore parents’ beliefs towards the teaching profession. This survey was conducted on 51 parents of teacher candidates in a teacher training institute. A research instrument, using questionnaires, adapted from FIT-Choice scale developed by Richardson and Watt (2006) was used to collect data from the population. The findings showed that parents, in general, have positive attitudes towards the teaching profession. They perceived teaching as a career highly valued by the society. Though the teaching job was viewed as difficult and requiring high expertise, the salary received commensurate their hard work and heavy workload. In terms of gender, male and female parents did not differ in their beliefs about the teaching profession. However, results indicated that educational attainment and income level had significant effect on parents’ beliefs on teaching as a profession. Implications and recommendations in relation to the findings are also included.

Keywords: beliefs, teaching profession, parents, teacher candidates

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Authors: Maya Arlini Puspasari, Shafira Karamina Alifah, Hardianto Iridiastadi

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High mental workload can lead to fatigue and further result in decreased concentration and work performance. This study is conducted to see the effects of mental workload towards mental fatigue. Mental fatigue measurement was conducted at the first and the last 10 minutes of the working time using electroencephalogram, while mental workload measurement was conducted after the work is completed using the NASA-TLX questionnaire. The result shows that there is an increase in alpha band which indicates an increase in mental fatigue. This study also shows absolute alpha is more sensitive compared to the relative alpha. This study proves that there is a relationship between mental workload and mental fatigue although not relatively strong.

Keywords: mental workload, electroencephalogram, customer care agents, NASA-TLX

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Authors: Amel Fayed, Shaden AlSubaih, Nouf Al-Qahtani, Asmaa Gosty, Asma Aljuhaimi

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Introduction: Sleep difficulties are vastly predominant among adults and affect different aspects of their life. Many literatures found out that females are more liable to suffer from sleeping problems. College students are typical example of people dealing with daily pressure and stress to fulfill the daily tasks and responsibilities. In addition to their ultimate goal of achieving excellent academic records which require their full concentration and effort. Consequently, many of them start complaining of sleep deprivations which can undesirably affect their academic achievements. This study was aiming to investigate how prevalent is sleeping disorders among different colleges in the university and its relation their academic achievements. Methods: A cross-sectional study of female university students at Princess Norah Bint Abdulrahman University using self-administered questionnaire was conducted. Insomnia Severity Index (ISI) was used to assess different grades of insomnia. Students were requested to answer the questions evaluating their sleeping habits over the last two weeks. Participants reported their latest Grade Point Average (GPA). According to ISI, insomnia severity is reported as ‘No clinically significant’, ‘Subthreshold ‘,’ Clinical moderate insomnia’ and ‘Clinical severe’. Results: In the current study, 228 students participated; 172(75.4%) from medical colleges and 56 (24.6%) from non-medical colleges. About 80% of them claimed to have never taken any medications to help them sleep while only three students confirmed their regular use of sleep-inducing medications. About 16% of the students drink milk or other hot drinks to help them fall asleep. None of the students was suspected of having obstructive sleep apnea or apparent psychiatric disorder. According to ISI, 182 (79.8%) students suffered from subthreshold insomnia, 37 (16.2%) had clinical insomnia (moderate severity) and 9 (3.9%) of students had sleeping problems of non-clinically significance level. However, none of students was found to have severe clinical insomnia. Clinical moderate insomnia was reported in 15.1% of medical students and 19.6% of non-medical students. Moreover, about 82% of medical students suffered from subthreshold insomnia compared to 73.2% of non-medical students. This difference was not statistically significant (P=0.24). About 63% of medical students and 48% of non-medical students believed that high percentage of their colleagues are suffering from insomnias (p-value 0.08) The association between GPA and insomnia revealed that; 19.5% of low GPA group compared to 9.3% of high GPA group had clinical moderate insomnia. This association was not statistically significant (p=0.15). The correlation between the GPA and the ISI score was negative but not conclusive (r=-0.08, p-value = 0.29). More than 92% of all students agreed that sleeping problems affect their academic achievement to varying degrees. Conclusion: our results suggest that insomnia is commonly prevalent among female university students and might affect the students’ achievement. This study provides preliminary data about the quality of sleep among medical and non-medical university students which may be used to promote the healthy sleeping habits among female students.

Keywords: academic achievement, females, insomnia, university student

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Authors: Tareq N. Issa

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The main pressuring challenges of global competition and high returns have forced businesses to shift their strategic competitive advantage from physical distribution management to integrated logistics management, finally moving into supply chain management. Conventionally, corporate profitability is a function of cost, capital employed, revenue and customer service. This article gives an insight into the effect of supply chain management on each of the above variables. It investigates the impact of the changing levels/ effects of these variables on corporate profitability and the means of measuring supply chain financial effectiveness. Information technology tools form the basis for supply chain optimal performance through alignment of supply chain systems in this ever increasing complexity in business decisions.

Keywords: corporate profitability, sypply chain systems, business decisions, competitive advanage

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Authors: Juliana V. Pereira, Adriana S. M. Batista, Jefferson P. Nascimento, Clascídia A. Furtado, Luiz O. Faria

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Exposure to ionizing radiation has been found to induce changes in poly(vinylidene fluoride) (PVDF) homopolymers. The high dose gamma irradiation process induces the formation of C=C and C=O bonds in its [CH₂-CF₂]_n main chain. The irradiation also provokes crosslinking and chain scission. All these radio-induced defects lead to changes in the PVDF crystalline structure. As a consequence, it is common to observe a decrease in the melting temperature (T_M) and melting latent heat (L_M) and some changes in its ferroelectric features. We have investigated the possibility of preparing nanocomposites of PVDF with graphene oxide (GO) through the radio-induction of molecular bonds. In this work, we discuss how the gamma radiation interacts with the nanocomposite crystalline structure.

Keywords: gamma irradiation, graphene oxide, nanocomposites, PVDF

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Authors: Adriana Garcia G., Alberto A. Escobar P., Amira D. Calvo L., Gabriel Lizama U., Alejandro Zepeda P., Fernando Martínez B., Susana Rincón A.

Abstract:

Different studies have recently been focused on the use of antioxidants such as polyphenols because of to its anticarcinogenic capacity. However, these compounds are highly sensible to environmental factors such as light and heat, so lose its long-term stability, besides possess an astringent and bitter taste. Nevertheless, the polyphenols can be protected by microcapsule formulation. In this sense, a rich source of polyphenols is sorghum, besides presenting a high starch content. Due to the above, the aim of this work was to obtain modified starches from sorghum by extrusion to encapsulate polyphenols the sorghum by spray drying. Polyphenols were extracted by ethanol solution from sorghum (Pajarero/red) and determined by the method of Folin-Ciocalteu, obtaining GAE at 30 mg/g. Moreover, was extracted starch of sorghum (Sinaloense/white) through wet milling (yield 32 %). The hydrolyzed starch was modified with three treatments: acetic anhydride (2.5g/100g), sodium tripolyphosphate (4g/100g), and sodium tripolyphosphate/ acetic anhydride (2g/1.25g by each 100 g) by extrusion. Processing conditions of extrusion were as follows: barrel temperatures were of 60, 130 and 170 °C at the feeding, transition, and high-pressure extrusion zones, respectively. Analysis of Fourier Transform Infrared spectroscopy (FTIR), showed bands exhibited of acetyl groups (1735 cm-1) and phosphates (1170 cm-1, 910 cm-1 and 525 cm-1), indicating the respective modification of starch. Besides, all modified starches not developed viscosity, which is a characteristic required for use in the encapsulation of polyphenols using the spray drying technique. As result of the modification starch, was obtained a water solubility index (WSI) from 33.8 to 44.8 %, and crystallinity from 8 to 11 %, indicating the destruction of the starch granule. Afterwards, microencapsulation of polyphenols was developed by spray drying, with a blend of 10 g of modified starch, 60 ml polyphenol extract and 30 ml of distilled water. Drying conditions were as follows: inlet air temperature 150 °C ± 1, outlet air temperature 80°C ± 5. As result of the microencapsulation: were obtained yields of 56.8 to 77.4 % and an efficiency of encapsulation from 84.6 to 91.4 %. The FTIR analysis showed evidence of microcapsules loaded with polyphenols in bands 1042 cm-1, 1038 cm-1 and 1148 cm-1. Analysis Differential scanning calorimetry (DSC) showed transition temperatures from 144.1 to 173.9 °C. For the order hand, analysis of Scanning Electron Microscopy (SEM), were observed rounded surfaces with concavities, typical feature of microcapsules produced by spray drying, how result of rapid evaporation of water. Finally, the modified starches were obtained by extrusion with good characteristics for use as cover materials by spray drying, where the phosphorylated starch was the best treatment in this work, according to the encapsulation yield, efficiency, and transition temperature.

Keywords: encapsulation, extrusion, modified starch, polyphenols, spray drying

Procedia PDF Downloads 291

Authors: Yun-Shan Tsai, Si-Ping Lin, En-Chieh Lin, Xin-Hong Chen, Shin-Yun Ho, Shin-Hong Huang, Ching-ju Hsieh

Abstract:

Background and significance: Uncorrected refractive errors and cataracts are the main visually debilitating ophthalmological abnormalities in adult participants with intellectual disability (ID). However, not all adult participants with ID may receive a regular and timely ophthalmological assessment. Consequently, some of the ocular diseases may not be diagnosed until late, thereby causing unnecessary ocular morbidity. In addition, recent clinical practice and researches have also suggested that eye-care services for this group are neglected. Purpose: To investigate the unmet need for eye care services, clinical characteristics of cataract, visual function, surgical outcome and prognostic predictors in adult participants with ID at Taipei City Hospital in Taiwan. Methods: This is a one-year prospective clinical study. We recruited about 120 eyes of 60 adult participants with ID who were received cataract surgery. Caregivers of all participants received a questionnaire on current eye care services. Clinical demographic data, such as age, gender, and associated systemic diseases or syndromes, were collected. All complete ophthalmologic examinations were performed 1 month preoperatively and 3 months postoperatively, including ocular biometry, visual function, refractive status, morphology of cataract, associated ocular features, anesthesia methods, surgical types, and complications. Morphology of cataract, visual and surgical outcome was analyzed. Results: A total of 60 participants with mean age 43.66 ± 13.94 years, including 59.02% male and 40.98% female, took part in comprehensive eye-care services. The prevalence of unmet need for eye care services was high (about 70%). About 50% of adult participants with ID have bilateral cataracts at the time of diagnosis. White cataracts were noted in about 30% of all adult participants with ID at the time of presentation. Associated ocular disorders were included myopic maculopathy (4.54%), corneal disorders (11.36%), nystagmus (20.45%), strabismus (38.64%) and glaucoma (2.27%). About 26.7% of adult participants with ID underwent extracapsular cataract extraction whereas a phacoemulsification was performed in 100% of eyes. Intraocular lens implantation was performed in all eyes. The most common postoperative complication was posterior capsular opacification (30%). The mean best-corrected visual acuity was significantly improved from preoperatively (mean log MAR 0.48 ± 0.22) to at 3 months postoperatively (mean log MAR 0.045 ± 0.22) (p < .05). Conclusions: Regular follow up will help address the need for eye-care services in participants with ID. A high incidence of bilateral cataracts, as well as white cataracts, was observed in adult participants with ID. Because of early diagnosis and early intervention of cataract, the visual and surgical outcomes of cataract are good, but the visual outcomes are suboptimal due to associated ocular comorbidities.

Keywords: adult participants with intellectual disability, cataract, cataract surgery

Procedia PDF Downloads 295

Authors: M. A. Ferhat, M. N. Boukhatem, F. Chemat

Abstract:

Lycopene extraction with petroleum derivatives as solvents has caused safety, health, and environmental concerns everywhere. Thus, finding a safe alternative solvent will have a strong and positive impact on environments and general health of the world population. d-limonene from the orange peel was extracted through a steam distillation procedure followed by a deterpenation process and combining this achievement by using it as a solvent for extracting lycopene from tomato fruit as a substitute of dichloromethane. Lycopene content of fresh tomatoes was determined by high-performance liquid chromatography after extraction. Yields obtained for both extractions showed that yields of d-limonene’s extracts were almost equivalent to those obtained using dichloromethane. The proposed approach using a green solvent to perform extraction is useful and can be considered as a nice alternative to conventional petroleum solvent where toxicity for both operator and environment is reduced.

Keywords: alternative solvent, d-limonene, extraction, lycopene

Procedia PDF Downloads 393

Authors: Önder M. Özdem

Abstract:

Producing and circulating films of professional standards have become technically easier with the development and widespread use of digital recording and distribution technologies. Additionally, film festivals on common platforms have rapidly increased in numbers and diversity. On the one hand, no-charge applications result in excessive submissions; thus, it complicates the evaluation and selection process. On the other hand, festival’s high submission fees may make the distribution of films with a limited budget very difficult. Inspired by the author’s engagement with the film industry as both a pre-jury member of an international film festival and an applicant to many festivals, this study discusses the causes and consequences of the increasing commercialization of film festivals. The author’s double identity, both as a jury and an applicant, provides a comparative perspective through which one can unfold the different dimensions and dynamics in the film production and distribution processes.

Keywords: commercialization, film distribution, film festivals, film production

Procedia PDF Downloads 62

Authors: Joe Dorbor Wuokolo

Abstract:

Thousands of smallholder farmers in Todee District, Montserrado county, are currently vulnerable to the negative impact of climate change. The district, which is the agricultural hot spot for the county, is faced with unfavorable changes in the daily temperature due to climate change. Farmers in the district have observed a dramatic change in the ratio of rainfall to sunshine, which has caused a chilling effect on their crop yields. However, there is a lack of documentation regarding how farmers perceive and respond to these changes and challenges. A study was conducted in the region to examine the perceptions of smallholder farmers regarding the negative impact of climate change, the adaptation strategies practice, and the barriers that hinder the process of advancing adaptation strategy. On purpose, a sample of 41 respondents from five towns was selected, including five town chiefs, five youth leaders, five women leaders, and sixteen community members. Women and youth leaders were specifically chosen to provide gender balance and enhance the quality of the investigation. Additionally, to validate the barriers farmers face during adaptation to climate change, this study interviewed eight experts from local and international organizations and government ministries and agencies involved in climate change and agricultural programs on what they perceived as the major barrier in both local and national level that impede farmers adaptation to climate change impact. SPSS was used to code the data, and descriptive statistics were used to analyze the data. The weighted average index (WAI) was used to rank adaptation strategies and the perceived importance of adaptation practices among farmers. On a scale from 0 to 3, 0 indicates the least important technique, and 3 indicates the most effective technique. In addition, the Problem Confrontation Index (PCI) was used to rank the barriers that prevented farmers from implementing adaptation measures. According to the findings, approximately 60% of all respondents considered the use of irrigation systems to be the most effective adaptation strategy, with drought-resistant varieties making up 30% of the total. Additionally, 80% of respondents placed a high value on drought-resistant varieties, while 63% percent placed it on irrigation practices. In addition, 78% of farmers ranked and indicated that unpredictability of the weather is the most significant barrier to their adaptation strategies, followed by the high cost of farm inputs and lack of access to financing facilities. 80% of respondents believe that the long-term changes in precipitation (rainfall) and temperature (hotness) are accelerating. This suggests that decision-makers should adopt policies and increase the capacity of smallholder farmers to adapt to the negative impact of climate change in order to ensure sustainable food production.

Keywords: adaptation strategies, climate change, farmers’ perception, smallholder farmers

Procedia PDF Downloads 72

Authors: Alev Atak

Abstract:

We study the endogeneity in the cryptocurrency market over the branching ratio of the Hawkes process and evaluate the movement of self-excitability in the financial markets. We consider a semi-parametric self-exciting point process regression model where the excitation function is assumed to be smooth and decreasing but otherwise unspecified, and the baseline intensity is assumed to be a linear function of the regressors. We apply the empirical analysis to the three largest crypto assets, i.e. Bitcoin - Ethereum - Ripple, and provide a comparison with other financial assets such as SP500, Gold, and the volatility index VIX observed from January 2015 to December 2020. The results depict variable and high levels of endogeneity in the basket of cryptocurrencies under investigation, underlining the evidence of a significant role of endogenous feedback mechanisms in the price formation process.

Keywords: hawkes process, cryptocurrency, endogeneity, reflexivity

Procedia PDF Downloads 66

Authors: B. Rajesh Kamath, J. Sundara Rajan, M. K. Veeraiah, M. Z. Kurian

Abstract:

Insulation performance of a gas insulated system is severely affected by particle contaminants. These metallic particles adversely affect the characteristics of insulating system. These particles can produce surface charges due to partial discharge activities. These particles which are free to move enhance the local electric fields. This paper deals with the influence of conducting particle placed in a co-axial duct on the discharge characteristics of gas mixtures. Co-axial duct placed in a high pressure chamber is used for the purpose. A gas pressure of 0.1, 0.2 and 0.3 MPa have been considered with a 10:90 SF₆ and N₂ gas mixtures. The 2D and 3D histograms of clean duct and duct with copper particle are discussed in this paper.

Keywords: coaxial duct, gas insulated system, gas mixtures, metallic particle, partial discharges, histograms

Procedia PDF Downloads 381

Authors: R. G. Ramírez-Chavarría, C. Sánchez-Pérez, V. Argueta-Díaz

Abstract:

In this paper we present the design of an optical device based on a Herriott multi-pass cell fabricated on a small sized acrylic slab for heat flux measurements using the deflection of a laser beam propagating inside the cell. The beam deflection is produced by the heat flux conducted to the acrylic slab due to a gradient in the refractive index. The use of a long path cell as the sensitive element in this measurement device, gives the possibility of high sensitivity within a small size device. We present the optical design as well as some experimental results in order to validate the device’s operation principle.

Keywords: heat flux, Herriott cell, optical beam deflection, thermal conductivity

Procedia PDF Downloads 634