Search results for: high surface quality

Authors: Min Chang Shin, Byung Hun Jeong, Jeong Sik Han, Jung Hoon Park

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In modern times, as flight speeds have increased due to improvements in aircraft and missile engine performance, thermal loads have also increased. Because of the friction heat of air flow with high speed on the surface of the vehicle, it is not easy to cool the superheat of the vehicle by the simple air cooling method. For this reason, a cooling method through endothermic heat is attracting attention by using a fuel that causes an endothermic reaction in a high-speed vehicle. There are two main ways of cooling the fuel through the endothermic reaction. The first is physical heat absorption. When the temperature rises, there is a sensible heat that accompanies it. The second is the heat of reaction corresponding to the chemical heat absorption, which absorbs heat during the fuel decomposes. Generally, since the decomposition reaction of the fuel proceeds at a high temperature, it does not achieve a great efficiency in cooling the high-speed flight body. However, when the catalyst is used, decomposition proceeds at a low temperature thereby increasing the cooling efficiency. However, when the catalyst is used as a powder, the catalyst enters the engine and damages the engine or the catalyst can deteriorate the performance due to the sintering. On the other hand, when used in the form of pellets, catalyst loss can be prevented. However, since the specific surface of pellet is small, the efficiency of the catalyst is low. And it can interfere with the flow of fuel, resulting in pressure loss and problems with fuel injection. In this study, we tried to maximize the performance of the catalyst by preparing a hollow fiber type pellet for zeolite ZSM-5, which has a higher amount of heat absorption, than other conventional pellets. The hollow fiber type pellet was prepared by phase inversion method. The hollow fiber type pellet has a finger-like pore and sponge-like pore. So it has a higher specific surface area than conventional pellets. The crystal structure of the prepared ZSM-5 catalyst was confirmed by XRD, and the characteristics of the catalyst were analyzed by TPD/TPR device. This study was conducted as part of the Basic Research Project (Pure-17-20) of Defense Acquisition Program Administration.

Keywords: catalyst, endothermic reaction, high-speed vehicle cooling, zeolite, ZSM-5

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Authors: Ya-Chuan Hsu, Wen-Chen Ouyang, Wei-Siang Huang

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Problem/Background: With constantly increasing aged populations, quality of life (QOL) in persons with dementia has become a significant research concern. The Alzheimer’s Related Quality of Life (ADRQL) is a high-validated, theory-derived, and multidimensional instrument. It has widely utilized in many countries, except in Taiwan. However, diverse results of quality of life from different countries by using the same measurement can provide the potential to help understand the impact of cultural contributor on QOL. Objective: To investigate the extent to which quality of life on older adults with dementia in Taiwan. Methods: Cross-sectional, descriptive study conducted in an assisting living facility affiliated with a daycare center in southern Taiwan. A purposeful sample of 34 participants was recruited. Inclusion criteria included those who were at least 65 years old, able to communicate, and diagnosed with mild to moderate dementia. The QOL was measured by Chinese version ADRQL. This observational instrument consists of 30 items that is divided into five subscales with the full range of each subscale scores from 0 to 100.0. Higher scores indicate better QOL. Results: The means for subscale of the Social Interaction, Awareness of Self, Feelings and Mood, Enjoyment of Activities, and Response to Surroundings were 87.9, 74.7, 91.3, 64.5, and 90.3, respectively. The overall mean for the ADQOL was 0.83. Conclusion: Findings suggest that the level of Enjoyment of Activities is the lowest and may convey information about a need of evaluation on arrangement of facility’s activities.

Keywords: dementia, quality of life, elders, Alzheimer’s related quality of life

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Authors: Jyh-Cherng Chen, Yi-Jie Lin

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This study tries to reuse the fly ash of municipal solid waste incinerator (MSWI) for the synthesis of zeolites. The fly ashes were treated with NaOH alkali fusion at different temperatures for 40 mins and then synthesized the zeolites with hydrothermal method at 105oC for different operation times. The effects of different operation conditions and the optimum synthesis parameters were explored. The specific surface area, surface morphology, species identification, adsorption capacity, and the reuse potentials of the synthesized zeolites were analyzed and evaluated. Experimental results showed that the optimum operation conditions for the synthesis of zeolite from the mixed fly ash were Si/Al=20, alkali/ash=1.5, alkali fusion reaction with NaOH at 800oC for 40 mins, hydrolysis with L/S=200 at 105oC for 24 hr, and hydrothermal synthesis at 105oC for 48 hr. The largest specific surface area of synthesized zeolite could be increased to 943.05m2/g. The influence of different operation parameters on the synthesis of zeolite from mixed fly ash followed the sequence of Si/Al > hydrolysis L/S> hydrothermal time > alkali fusion temperature > alkali/ash ratio. The XRD patterns of synthesized zeolites were identified to be similar with the ZSM-23 zeolite. The adsorption capacities of synthesized zeolite for pollutants were increased as rising the specific surface area of synthesized zeolite. In summary, MSWI fly ash can be treated and reused to synthesize the zeolite with high specific surface area by the alkali fusion and hydrothermal method. The zeolite can be reuse for the adsorption of various pollutants. They have great potential for development.

Keywords: alkali fusion, hydrothermal, fly ash, zeolite

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Authors: Rui Wang, Shanfa Tang, Yuanwu Dong, Siyao Wang, Zhaowen Jiang, Di Han

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A sulfonate Gemini surfactant sodium N,N`-bis(tetradecanoyl) propanediamine dipropyl sulfonate (GNS-14) was synthesized from 1,3-propanediamine, tetradecanoyl chloride, and1,3-propanesulfonic lactone. GNS-14 was characterized by FT-IR, 1H NMR. The surface activity, interfacial activity, and emulsification properties of GNS-14 solution were systematically studied. The critical micelle concentration (CCMC) of GNS-14 surfactant was 0.056 mmol/L, and the surface tension (γCMC) was 18.2 mN/m; at 50℃, 0.5% GNS-14 solution can reduce the oil-water interfacial tension to 6.5×10−2 mN/m. GNS-14 has excellent surface activity, interfacial activity, and emulsifying properties.

Keywords: gemini surfactants, surface tension, low interfacial tension, emulsifying properties

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Authors: Anat Thanpinta

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This research aimed to study on the efficiency of wastewater treatment by comparing the different aeration times of surface aerators in Suan Sunandha Rajabhat University. In doing so, the operation of surface aerators was divided into 2 groups which included the groups of 8 hours (8-0/opened-closed) and 4 hours (2-2/opened-closed) of aeration time per day. As a result of the study, it was found that the efficiency of wastewater treatment in the forms of DO, BOD, turbidity and NO2- by 8 hours (8-0/opened-closed) and 4 hours (2-2/opened-closed) of aeration time per day of surface aerators was not statistically different [Sig. = .644, .488, .716 and .054 > α (.05)] while the efficiency in the forms of NO3- and P was significantly different at the statistical level of .01 [Sig. = .001 and .000 < α (.01)].

Keywords: aeration time, surface aerator, wastewater treatment, efficiency

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Authors: Ruth Catacolí, Hector Garcia

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Colombia Urban Areas shows a decreasing of their air quality, no matter the actions developed by the Government facing the mitigation of pressure factors related with air pollution. Examples of these actions were the fossil fuel quality improvement policies (FFQI). This study evaluated the impact of three FFQI in the air quality of Bogotá during the period 1990 - 2006: The phase-out of lead in the gasoline; the sulfur reduction in diesel oil consumed in Bogotá and the oxygenation of gasoline through the addition of ethanol. The results indicate that only the policy of phase-out of lead in gasoline has been effective, showing dropping of lead oxides concentration in the air. Some stakeholders believe that the FFQI evaluated in the study are environmental policies, but no one of these policies has been supported by an environmental impact assessment that shows specific benefits in air quality. The research includes some fuel policy elements to achieve positive impact on the air quality in the urban centers of Colombia.

Keywords: policy assessment, fuel quality, urban air quality, air quality management

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Authors: Diego de Almeida Pereira

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The roughness index of a road is considered the most important parameter about the quality of the pavement, as it has a close relation with the comfort and safety of the road users. Such condition can be established by means of functional evaluation of pavement surface deviations, measured by the International Roughness Index (IRI), an index that came out of the international evaluation of pavements, coordinated by the World Bank, and currently owns, as an index of limit measure, for purposes of receiving roads in Brazil, the value of 2.7 m/km. This work make use of the e.IRI parameter, obtained by the Roadroid app. for smartphones which use Android operating system. The choice of such application is due to the practicality for the user interaction, as it possesses a data storage on a cloud of its own, and the support given to universities all around the world. Data has been collected for six months, once in each month. The studies begun in March 2018, season of precipitations that worsen the conditions of the roads, besides the opportunity to accompany the damage and the quality of the interventions performed. About 350 kilometers of sections of four federal highways were analyzed, BR-020, BR-040, BR-060 and BR-070 that connect the Federal District (area where Brasilia is located) and surroundings, chosen for their economic and tourist importance, been two of them of federal and two others of private exploitation. As well as much of the road network, the analyzed stretches are coated of Hot Mix Asphalt (HMA). Thus, this present research performs a contrastive discussion between comfort conditions and safety of the roads under private exploitation in which users pay a fee to the concessionaires so they could travel on a road that meet the minimum requirements for usage, and regarding the quality of offered service on the roads under Federal Government jurisdiction. And finally, the contrast of data collected by National Department of Transport Infrastructure – DNIT, by means of a laser perfilometer, with data achieved by Roadroid, checking the applicability, the practicality and cost-effective, considering the app limitations.

Keywords: roadroid, international roughness index, Brazilian roads, pavement

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Authors: Soumita Mitra, Santosh Kumar Sarkar

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Hooghly river estuary (HRE), situated at the north eastern part of Bay of Bengal has global significance due to its holiness. It is of immense importance to the local population as it gives perpetual water supply for various activities such as transportation, fishing, boating, bathing etc. to the local people who settled on both the banks of this estuary. This study was done to assess the dissolved and particulate trace metal in the estuary covering a stretch of about 175 Km. The water samples were collected from the surface (0-5 cm) along the salinity gradient and metal concentration were studied both in dissolved and particulate phase using Graphite Furnace Atomic Absorption Spectrophotometer (GF-AAS) along some physical characteristics such as water temperature, salinity, pH, turbidity and total dissolved solids. Although much significant spatial variation was noticed but little enrichment was found along the downstream of the estuary. The mean concentration of the metals in the dissolved and particulate phase followed the same trend and as follows: Fe>Mn>Cr>Zn>Cu>Ni>Pb. The concentration of the metals in the particulate phase were much greater than that in dissolved phase which was also depicted from the values of the partition coefficient (Kd)(ml mg-1). The Kdvalues ranged from 1.5x105 (in case of Pb) to 4.29x106 (in case of Cr). The high value of Kd for Cr denoted that the metal Cr is mostly bounded with the suspended particulate matter while the least value for Pb signified it presence more in dissolved phase. Moreover, the concentrations of all the studied metals in the dissolved phase were many folds higher than their respective permissible limits assested by WHO 2008, 2009 and 2011. On the other hand, according to Sediment Quality Guidelines (SQGs), Zn, Cu and Ni in the particulate phase lied between ERL and ERM values but Cr exceeded ERM values at all the stations confirming that the estuary is mostly contaminated with the particulate Cr and it might cause frequent adverse effects on the aquatic life. Multivariate statistics Cluster analysis was also performed which separated the stations according to the level of contamination from several point and nonpoint sources. Thus, it is found that the estuarine system is much polluted by the toxic metals and further investigation, toxicological studies should be implemented for full risk assessment of this system, better management and restoration of the water quality of this globally significant aquatic system.

Keywords: dissolved and particulate phase, Hooghly river estuary, partition coefficient, surface water, toxic metals

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Authors: Chang Liu, Rui Xing, Liyan Tang, Guohong Wang

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Entrepreneurial actions are based on entrepreneurial decisions. The quality of decisions influences entrepreneurial activities and subsequent new venture performance. Uncertainty of surroundings put heightened demands on the team as a whole, and each team member. Diverse team composition provides rich information, which a team can draw when making complex decisions. However, team heterogeneity may cause emotional conflicts, which is adverse to team outcomes. Thus, the effects of team heterogeneity on team outcomes are complex. Although team heterogeneity is an essential factor influencing entrepreneurial decision-making, there is a lack of empirical analysis on under what conditions team heterogeneity plays a positive role in promoting decision-making quality. Entrepreneurial teams always struggle with complex tasks. How a team shapes its teamwork is key in resolving constant issues. As a collective regulatory process, team reflexivity is characterized by continuous joint evaluation and discussion of team goals, strategies, and processes, and adapt them to current or anticipated circumstances. It enables diversified information to be shared and overtly discussed. Instead of hostile interpretation of opposite opinions team members take them as useful insights from different perspectives. Team reflexivity leads to better integration of expertise to avoid the interference of negative emotions and conflict. Therefore, we propose that team reflexivity is a conditional factor that influences the impact of team heterogeneity on high-quality entrepreneurial decisions. In this study, we identify team heterogeneity as a crucial determinant of entrepreneurial decision quality. Integrating the literature on decision-making and team heterogeneity, we investigate the relationship between team heterogeneity and entrepreneurial decision-making quality, treating team reflexivity as a moderator. We tested our hypotheses using the hierarchical regression method and the data gathered from 63 teams and 205 individual members from 45 new firms in China's first-tier cities such as Beijing, Shanghai, and Shenzhen. This research found that both teams' education heterogeneity and teams' functional background heterogeneity were significantly positively related to entrepreneurial decision-making quality, and the positive relation was stronger in teams with a high level of team reflexivity. While teams' specialization of education heterogeneity was negatively related to decision-making quality, and the negative relationship was weaker in teams with a high level of team reflexivity. We offer two contributions to decision-making and entrepreneurial team literatures. Firstly, our study enriches the understanding of the role of entrepreneurial team heterogeneity in entrepreneurial decision-making quality. Different from previous entrepreneurial decision-making literatures, which focus more on decision-making modes of entrepreneurs and the top management team, this study is a significant attempt to highlight that entrepreneurial team heterogeneity makes a unique contribution to generating high-quality entrepreneurial decisions. Secondly, this study introduced team reflexivity as the moderating variable, to explore the boundary conditions under which the entrepreneurial team heterogeneity play their roles.

Keywords: decision-making quality, entrepreneurial teams, education heterogeneity, functional background heterogeneity, specialization of education heterogeneity

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Authors: Maria Paula Santos, Ana Lucas

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Organizations support their operations and decision making on the data they have at their disposal, so the quality of these data is remarkably important and Data Quality (DQ) is currently a relevant issue, the literature being unanimous in pointing out that poor DQ can result in large costs for organizations. The literature review identified and described 24 Critical Success Factors (CSF) for Data Quality Management (DQM) that were presented to a panel of experts, who ordered them according to their degree of importance, using the Delphi method with the Q-sort technique, based on an online questionnaire. The study shows that the five most important CSF for DQM are: definition of appropriate policies and standards, control of inputs, definition of a strategic plan for DQ, organizational culture focused on quality of the data and obtaining top management commitment and support.

Keywords: critical success factors, data quality, data quality management, Delphi, Q-Sort

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Authors: O. I. Ojo, W. B. R. Graham, I. W. Pishiria

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The quality of groundwater used for irrigation in Kebbi State, northwestern Nigeria was evaluated. Open-well, tube-well and borehole water samples were collected from various locations in the State. The water samples analyzed had pH values below the normal range for irrigation water and very low to moderate salinity (electrical conductivity 0.05-0.82 dS.m-1). The adjusted sodium adsorption ratio values in all the samples were also very low (<0.2), indicating very low sodicity hazards. However, irrigation water of very low salinity (<0.2dS.m-1) and low SAR can lead to problems of infiltration into soils. The Ca: Mg ratio (<1) in most of the samples may lead to Ca deficiency in soils after long term use. The nitrate concentration in most of the samples was high ranging from 4.5 to >50mg/L.

Keywords: ground water quality, irrigation, characteristics, soil drainage, salinity, Fadama

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Authors: Adesola C. Odole, Michael O. Ogunlana, Nse A. Odunaiya, Olufemi O. Oyewole, Chidozie E. Mbada, Ogochukwu K. Onyeso, Ayomikun F. Ayodeji, Opeyemi M. Adegoke, Iyanuoluwa Odole, Comfort T. Sanuade, Moyosooreoluwa E. Odole, Oluwagbohunmi A. Awosoga

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Purpose: The Nigerian healthcare industry is bedeviled with infrastructural decay, inadequate funding and staffing, and a dysfunctional healthcare system. This study investigated the influence of health professionals’ well-being and quality of work-life (QoWL) on the quality of care (QoC) of patients in Nigeria. Methods: The study was a multicentre cross-sectional survey conducted at four tertiary health institutions in southwest Nigeria. Participants’ demographic information, well-being, quality of work-life, and quality of care were obtained using four standardized questionnaires. Data were summarized using descriptive statistics of frequency (percentage) and mean (standard deviation). Inferential statistics included Chi-square, Pearson’s correlation, and independent samples t-test analyses. Results: Medical practitioners (n=609) and nurses (n=570) constituted 74.6% of all the health professionals, with physiotherapists, pharmacists, and medical laboratory scientists constituting 25.4%. The mean (SD) participants’ well-being = 71.65% (14.65), quality of life = 61.8% (21.31), quality of work-life = 65.73% (10.52) and quality of care = 70.14% (12.77). Participants’ quality of life had a significant negative correlation with the quality of care, while well-being and quality of work-life had a significant positive correlation with the quality of care. Conclusion: We concluded that health professionals’ well-being and quality of work-life are important factors that influence their productivity and, ultimately, the quality of care rendered to patients. The hospital management and policymakers should ensure improved work-related factors to improve the well-being of health professionals. This will enhance the quality of care given to patients and ultimately reduce brain drain and medical tourism.

Keywords: health professionals, quality of care, quality of life, quality of work-life, well-being

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Authors: M. H. Alhajeri, Hamad M. Alhajeri, A. H. Alenezi

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This paper reports a Computational Fluid Dynamics (CFD) investigation for a high-temperature high-pressure filtration (ceramic candle filter). However, parallel flow to the filter is considered in this study. Different face (filtration) velocities are examined using the CFD code, FLUENT. Different sizes of particles are tracked through the domain to find the height at which the particles will impinge on the filter surface. Furthermore, particle distribution around the filter (or filter cake) is studied to design efficient cleaning mechanisms. Gravity effect to the particles with various inlet velocities and pressure drop are both considered. In the CFD study, it is found that the gravity influence should not be ignored if the particle sizes exceed 1 micron.

Keywords: fluid flow, CFD, filtration, HTHP

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Authors: Usman Yakubu, Muktar Haruna

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The paper examines the impact of the audit committee on the earning quality of the listed consumer goods sector in Nigeria. The study used data collected from annual reports and accounts of the 13 sampled companies for the periods 2007 to 2018. Data were analyzed by means of descriptive statistics to provide summary statistics for the variables; also, correlation analysis was carried out using the Pearson correlation technique for the correlation between the dependent and independent variables. Regression was employed using the Generalized Least Square technique since the data has both time series and cross sectional attributes (panel data). It was found out that the audit committee had a positive and significant influence on the earning quality in the listed consumer goods companies in Nigeria. Thus, the study recommends that competency and personal integrity should be the worthwhile attributes to be considered while constituting the committee; this could enhance the quality of accounting information. In addition to that majority of the committee members should be independent directors in order to allow a high level of independency to be exercised.

Keywords: earning quality, corporate governance, audit committee, financial reporting

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Authors: Seok-Tae Yoon, Jae-Yeong Choi, Gyu-Mok Jeon, Yong-Jin Cho, Jong-Chun Park

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Conventional submarines obtain propulsive force by using an electric propulsion system consisting of a diesel generator, battery, motor, and propeller. In the underwater, the submarine uses the electric power stored in the battery. After that, when a certain amount of electric power is consumed, the submarine floats near the sea water surface and recharges the electric power by using the diesel generator. The voyage carried out while charging the power is called a snorkel, and the high-temperature exhaust gas from the diesel generator forms a heat distribution on the sea water surface. The heat distribution is detected by weapon system equipped with thermo-detector and that is the main cause of reducing the survivability of the submarine. In this paper, an experimental study was carried out to establish optimal operating conditions of a submarine for reduction of infrared signature radiated from the sea water surface. For this, a hot gas generating system and a round acrylic water tank with adjustable water level were made. The control variables of the experiment were set as the mass flow rate, the temperature difference between the water and the hot gas in the water tank, and the water level difference between the air outlet and the water surface. The experimental instrumentation used a thermocouple of T-type to measure the released air temperature on the surface of the water, and a thermography system to measure the thermal energy distribution on the water surface. As a result of the experiment study, we analyzed the correlation between the final released temperature of the exhaust pipe exit in a submarine and the depth of the snorkel, and presented reasonable operating conditions for the infrared signature reduction of submarine.

Keywords: experiment study, flow rate, infrared signature, snorkeling, thermography

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Authors: Theena Thayalan, K. N. Ramesh Babu

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Machining induced residual stress (RS) is one of the most important surface integrity parameters that characterize the near surface layer of a mechanical component, which plays a crucial role in controlling the performance, especially its fatigue life. Since experimental determination of RS is expensive and time consuming, it would be of great benefit if they could be predicted. In such case, it would be possible to select the cutting parameters required to produce a favorable RS profile. In the present study, an effort has been made to develop a 'two dimensional finite element model (FEM)' to simulate orthogonal cutting process and to predict surface and sub-surface RS using the commercial FEA software DEFORM-2D. The developed finite element model has been validated through experimental investigation of RS. In the experimentation, the orthogonal cutting tests were carried out on AISI 4340 by varying the cutting speed (VC) and uncut chip thickness (f) at three levels and the surface & sub-surface RS has been measured using XRD and Electro polishing techniques. The comparison showed that the RS obtained using developed numerical model is in reasonable agreement with that of experimental data.

Keywords: FEM, machining, residual stress, XRF

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Authors: Majid Javanmard

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In this study, the effects of coating with whey protein concentrate (7.5% w/v) alone and/or in combination with rice bran oil (0.2, 0.4, 0.6 g in 100 ml coating solution) and Zataria multiflora extract (1 and 2 μL in 100 ml coating solution) on the quality attributes and egg shelf life were carefully observed and analyzed. Weight loss, Haugh index, yolk index, pH, air cell depth, shell strength and the impact of this coating on the microbial load of the eggs surface were studied at the end of each week (during the 4 weeks of storage in a room environment temperature and humidity). After 4 weeks of storage, it was observed that the weight loss in all of the treated eggs with whey protein concentrate and 0.2 gr of rice bran oil (experimental group) was significantly lower than that of the control group(P < 0/05). With regard to Haugh index and yolk index, egg shelf life increased about 4 weeks compared with the control samples. Haugh Index changes revealed that the coated samples remained at grade A after 3 weeks of storage, while the control samples were relegated from grade AA to B after one week. Haugh and yolk Indices in all coated eggs were more than those of the control group. In the coated groups, Haugh and yolk indices of the coated samples with whey protein concentrate and 0.2 g rice bran oil and with whey protein concentrate and 0.2g of rice bran oil and 1 micro liter of Zataria multiflora extract were more than those of the other coated eggs and the control group eggs. PH values of the control group were higher than those of the coated groups during the storage of the eggs. The shell strength of the coated group was more than that of the control group (uncoated) and in coated samples, whey protein concentrate and 0.2 gr of rice bran oil coated samples had high shell strength. In the other treatments, no significant differences were observed. The depth of the air cell of the coated groups was determined to be less than that of the control group during the storage period. The minimum inhibitory concentration was 1 μL of Zataria multiflora extract. The results showed that 1 μL concentration of Zataria multiflora extract reduces the microbial load of the egg shell surface to 87% and 2 μL reduced total bacterial load to zero. In sensory evaluation, from evaluator point of view, the coated eggs had more overall acceptance than the uncoated group (control), and in the treatment group coated eggs, those containing a low percentage of rice bran oil had higher overall acceptability. In conclusion, coating as a practical and cost effective method can maintain the quality parameters of eggs and lead to durability of supply conditions in addition to the product marketability.

Keywords: edible coating, chicken egg, whey protein concentrate, rice bran oil, Zataria multiflora extract, shelf life

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Authors: E. Isaac, I. Jalo, Y. Alkali, A. Ajani, A. Rasaki, Y. Jibrin, K. Mustapha, S. Charanchi, A. Kudi, H. Danlami

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Introduction: Hepatitis B infection is endemic in sub-Saharan Africa, where transmission predominantly occurs in infants and children by perinatal and horizontal routes. The risk of chronic infection peaks when infection is acquired early. Materials and Methods: Records of Hepatitis B surface and envelope antigen results in Federal Teaching Hospital, Gombe between May 2000 and May 2015 were retrieved and analyzed. Results: Paediatric outpatient visits and in-patient admissions were 64,193 accounting for 13% of total. Individuals tested for Hepatitis B surface antigenaemia were 23,866. Children aged 0-18 years constituted 11% (2,626). Among children tested, males accounted for 52.8% (1386/2626) and females 47.2% (1240/2626). Infants contributed 65 (2.3%); 1-4 year old children 309 (11.7%); 5-9 year old children 564 (21.4%) and adolescents 1717 (65.1%). HbSAg sero-positivity was 18% (496/2626) among children tested. The highest number of children tested per year was in 2009 (518) and 2014 (569) and the lowest, in the first study year (62). The highest sero-positivity rate was in 2010; 21.7% (54/255). Children aged 0-18years accounted for 10.5% (496/4720) of individuals with Hepatitis B surface antigenaemia. Sero-positivity was 3.1% (2/65); 12.9% (40/309); 18.1% (102/564); and 20.5% (352/1717) in infants, children ages 1-4years, 5-9years and adolescents respectively. 2.5% (1/40) and 4% (1/25) of male and female infants respectively had HbSAg. Among children aged 1-4years, 15.1% (30/198) of males and 9.0% (10/111) of females were seropositive; 14.8% (52/350) and 22% (50/224) of male and female 5-9year old children respectively has HbSAg. 14.3% (138/943) of adolescent females had Hepatitis B surface antigenaemia. Adolescent males demonstrated the highest sero-positivity rate 27.6% (214/774). 97.3% (483/496) of children who demonstrated Hepatitis B surface antigenaemia were tested for dual carriage with the e antigen. Males accounted for 296/483 (63.1%) and females 187/483 (36.9%). Infants constituted 0.97% (4/482); children aged 1-4years, 5-9years and adolescents were 6.8% (33/483); 20.9% (100/483) and 71.3% (342/483) respectively. 17.6% (85/483) of children tested had HBe antigenaemia. Of these, males accounted for 69.4% (59/85). 1.2% (1/85) were infants; 9.4% (8/85%) 1-4years; 22.3% (19/85) 5-9years and 68.2% (58/85) adolescents. 25% (1/4) infants; 24% (8/33) children aged 1-4 years; 19% (19/100) 5-9 year old children and 16.9% (58/342) adolescents had dual carriage. Infants and young children demonstrated the highest rate of dual carriage but were less likely to be tested for dual carriage 37/42 (88%) than their 5-9 year old 98% (100/102) and adolescent 342/352 (97%) counterparts. HB e antigen positivity rate was 45.4% (59/130) males and 36.0% (27/75) in females. Conclusion: Hepatitis B surface antigenaemia is high among adolescent males. Infants and young children who had HBSAg had the highest rate of envelope antigen carriage. Testing in pregnancy, vaccination programmes and prophylaxis need to be strengthened.

Keywords: children, dual carriage, Gombe, hepatitis B

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Authors: Chetsada Noknoi

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This research aims to study the quality of life of alien workers in Thailand and to compare the quality of work life of alien workers based on personal factors and work factors. Data analysis is performed using frequencies, percentage, mean standard deviation, t-test and ANOVA. Findings will benefit to the relevant authorities to be aware of the quality of life of alien workers in Thailand. This will help to find ways to enhance the quality of life of alien workers. It also brings awareness to the problems and obstacles that alien workers face in their work and life. It is a strategic approach to improve the management of the country's alien workers to be more efficient and effective. Moreover, the knowledge can be the basis of service to the society in different ways.

Keywords: quality of work life, alien worker, contemporary marketing, management

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Authors: Deepak

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WEDM is an amazingly potential electro-wire process for machining of hard metal compounds and metal grid composites without making contact. Wire electrical machining is a developing noncustomary machining process for machining hard to machine materials that are electrically conductive. It is an exceptionally exact, precise, and one of the most famous machining forms in nontraditional machining. WEDM has turned into the fundamental piece of many assembling process ventures, which require precision, variety, and accuracy. In the present examination, AA-6063 is utilized as a workpiece, and execution investigation is done to discover the critical control factors. Impact of different parameters like a pulse on time, pulse off time, servo voltage, peak current, water pressure, wire tension, wire feed upon surface hardness has been researched while machining on AA-6063. RSM has been utilized to advance the yield variable. A variety of execution measures with input factors was demonstrated by utilizing the response surface methodology.

Keywords: AA-6063, response surface methodology, WEDM, surface roughness

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Authors: Rejane Maria P. da Silva, Mariana X. Milagre, João Victor de S. Araujo, Leandro A. de Oliveira, Renato A. Antunes, Isolda Costa

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The Al-Cu-Li alloys are advanced materials for aerospace application because of their interesting mechanical properties and low density when compared with conventional Al-alloys. However, Al-Cu-Li alloys are susceptible to localized corrosion. The near-surface deformed layer (NSDL) induced by the rolling process during the production of the alloy and its removal by polishing can influence on the corrosion susceptibility of these alloys. In this work, the influence of surface preparation effects on the electrochemical activity of AA2098-T351 (Al–Cu–Li alloy) was investigated using a correlation between surface chemistry, microstructure, and electrochemical activity. Two conditions were investigated, polished and as-received surfaces of the alloy. The morphology of the two types of surfaces was investigated using confocal laser scanning microscopy (CLSM) and optical microscopy. The surface chemistry was analyzed by X-ray Photoelectron Spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS). Global electrochemical techniques (potentiodynamic polarization and EIS technique) and a local electrochemical technique (Localized Electrochemical Impedance Spectroscopy-LEIS) were used to examine the electrochemical activity of the surfaces. The results obtained in this study showed that in the as-received surface, the near-surface deformed layer (NSDL), which is composed of Mg-rich bands, influenced the electrochemical behavior of the alloy. The results showed higher electrochemical activity to the polished surface condition compared to the as-received one.

Keywords: Al-Cu-Li alloys, surface preparation effects, electrochemical techniques, localized corrosion

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Authors: Okugbe Ebiotubo Ohore, Jingli Zhang, Binessi Edouard Ifon, Mathieu Nsenga Kumwimba, Xiaoying Mu, Dai Kuang, Zhen Wang, Ji-Dong Gu, Guojing Yang

Abstract:

Antibiotic pollution and the evolution of antibiotic resistance genes (ARGs) are increasingly viewed as major threats to both ecosystem security and human health, and has drawn attention. This study investigated the fate of antibiotics in aqueous and sedimentary substrates and the impact of ecosystem shifts between water and sedimentary phases on resistome profiles. The findings indicated notable variations in the concentration and distribution patterns of antibiotics across various environmental phases. Based on the partition coefficient (Kd), the total antibiotic concentration was significantly greater in the surface water (1405.45 ng/L; 49.5%) compared to the suspended particulate matter (Kd =0.64; 892.59 ng/g; 31.4%) and sediment (Kd=0.4; 542.64 ng/g; 19.1%). However, the relative abundance of ARGs in surface water and sediment was disproportionate to the abundance of antibiotics concentration, and sediments were the predominant ARGs reservoirs. Phylogenetic divergence of the microbial communities between the surface water and the sedimentary ecosystems potentially played important roles in driving the ARGs profiles between the two distinctive ecosystems. ARGs of Clinical importance; including blaGES, MCR-7.1, ermB, tet(34), tet36, tetG-01, and sul2 were significantly increased in the surface water, while blaCTX-M-01, blaTEM, blaOXA10-01, blaVIM, tet(W/N/W), tetM02, and ermX were amplified in the sediments. cfxA was an endemic ARG in surface-water ecosystems while the endemic ARGs of the sedimentary ecosystems included aacC4, aadA9-02, blaCTX-M-04, blaIMP-01, blaIMP-02, bla-L1, penA, erm(36), ermC, ermT-01, msrA-01, pikR2, vgb-01, mexA, oprD, ttgB, and aac. These findings offer a valuable information for the identification of ARGs-specific high-risk reservoirs.

Keywords: antibiotic resistance genes, microbial diversity, suspended particulate matter, sediment, surface water

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Authors: Farida Mellah, Abdelhak Boutaleb, Bachir Henni, Dalila Berdous, Abdelhamid Mellah

Abstract:

Context/Purpose: One of the largest mining operations for lead and zinc deposits in northwestern Algeria in more than thirty years, El Abed is now the abandoned mine that has been inactive since 2004, leaving large amounts of accumulated mining waste under the influence of Wind, erosion, rain, and near agricultural lands. Materials & Methods: This study aims to verify the concentrations and sources of heavy metals for surface samples containing randomly taken soil. Chemical analyses were performed using iCAP 7000 Series ICP-optical emission spectrometer, using a set of environmental quality indicators by calculating the enrichment factor using iron and aluminum references, geographic accumulation index and geographic information system (GIS). On the basis of the spatial distribution. Results: The results indicated that the average metal concentration was: (As = 30,82),(Pb = 1219,27), (Zn = 2855,94), (Cu = 5,3), mg/Kg,based on these results, all metals except Cu passed by GBV in the Earth's crust. Environmental quality indicators were calculated based on the concentrations of trace metals such as lead, arsenic, zinc, copper, iron and aluminum. Interpretation: This study investigated the concentrations and sources of trace metals, and by using quality indicators and statistical methods, lead, zinc, and arsenic were determined from human sources, while copper was a natural source. And based on the spatial analysis on the basis of GIS, many hot spots were identified in the El-Abed region. Conclusion: These results could help in the development of future treatment strategies aimed primarily at eliminating materials from mining waste.

Keywords: soil contamination, trace metals, geochemical indices, El Abed mine, Algeria

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Authors: Long Wang, Yongjin Feng, Xiaofang Luo

Abstract:

Tritium permeation through structural materials is a significant issue for fusion demonstration (DEMO) reactor blankets in terms of fuel cycle efficiency and radiological safety. Reduced activation ferritic (RAFM) steel CLF-1 is a prime candidate for the China’s CFETR blanket structural material, facing high permeability of hydrogen isotopes at reactor operational temperature. To confine tritium as much as possible in the reactor, surface modification of the steels including fabrication of tritium permeation barrier (TPB) attracts much attention. As a new alloy system, high entropy alloy (HEA) contains at least five principal elements, each of which ranges from 5 at% to 35 at%. This high mixing effect entitles HEA extraordinary comprehensive performance. So it is attractive to lead HEA into surface alloying for protective use. At present, studies on the hydrogen isotope permeability of HEA coatings is still insufficient and corresponding mechanism isn’t clear. In our study, we prepared three kinds of HEA coatings, including AlCrTaTiZr, (AlCrTaTiZr)N and (AlCrTaTiZr)O. After comprehensive characterization of SEM, XPS, AFM, XRD and TEM, the structure and composition of the HEA coatings were obtained. Deuterium permeation tests were conducted to evaluate the hydrogen isotope permeability of AlCrTaTiZr, (AlCrTaTiZr)N and (AlCrTaTiZr)O HEA coatings. Results proved that the (AlCrTaTiZr)N and (AlCrTaTiZr)O HEA coatings had better hydrogen isotope permeation resistance. Through analyzing and characterizing the hydrogen isotope permeation results of the corroded samples, an internal link between hydrogen isotope permeation behavior and structure of HEA coatings was established. The results provide valuable reference in engineering design of structural and TPB materials for future fusion device.

Keywords: high entropy alloy, hydrogen isotope permeability, tritium permeation barrier, fusion demonstration reactor

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Authors: Valentine A. Chanturiya, Igor Zh. Bunin, Maria V. Ryazantseva

Abstract:

The modification of structural and chemical properties of fluorite, scheelite and calcite under the impact of high-power electromagnetic pulses (HPEMP-treatment) were studied with the help of adsorption of acid-base indicators and atomic – force microscopy (AFM). The HPEMP-treatment during the space of 30 seconds resulted in the intensification of fluorite surface the electron-donating ability and acceptor properties of calcite and scheelite surfaces. High-power electromagnetic treatment of the single minerals resulted in the improvement of the calciferous minerals floatability. The rising of the scheelite recovery is 10 – 12%, fluorite – 5 – 6%, calcite – 7 – 8%.

Keywords: calcite, fluorite, scheelite, high power electromagnetic pulses, floatability

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Authors: G. Olamiti; TK. Takalani; D. Beswa, AIO Jideani

Abstract:

The study investigated the effects of malting and fermentation times on some chemical, functional properties and microstructural behaviour of Agrigreen, Babala pearl millet cultivars and sorghum flours using response surface methodology (RSM). Central Composite Rotatable Design (CCRD) was performed on two independent variables: malting and fermentation times (h), at intervals of 24, 48, and 72, respectively. The results of dependent parameters such as pH, titratable acidity (TTA), Water absorption capacity (WAC), Oil absorption capacity (OAC), bulk density (BD), dispersibility and microstructural behaviour of the flours studied showed a significant difference in p < 0.05 upon malting and fermentation time. Babala flour exhibited a higher pH value at 4.78 at 48 h malted and 81.9 fermentation times. Agrigreen flour showed a higher TTA value at 0.159% at 81.94 h malted and 48 h fermentation times. WAC content was also higher in malted and fermented Babala flour at 2.37 ml g-1 for 81.94 h malted and 48 h fermentation time. Sorghum flour exhibited the least OAC content at 1.67 ml g-1 at 14 h malted and 48 h fermentation times. Agrigreen flour recorded the least bulk density, at 0.53 g ml-1 for 72 h malted and 24 h fermentation time. Sorghum flour exhibited a higher content of dispersibility, at 56.34%, after 24 h malted and 72 h fermented time. The response surface plots showed that increased malting and fermentation time influenced the dependent parameters. The microstructure behaviour of malting and fermentation times of pearl millet varieties and sorghum flours showed isolated, oval, spherical, or polygonal to smooth surfaces. The optimal processing conditions, such as malting and fermentation time for Agrigreen, were 32.24 h and 63.32 h; 35.18 h and 34.58 h for Babala; and 36.75 h and 47.88 h for sorghum with high desirability of 1.00. The validation of the optimum processing malting and fermentation times (h) on the dependent improved the experimented values. Food processing companies can use the study's findings to improve food processing and quality.

Keywords: Pearl millet, malting, fermentation, microstructural behaviour

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Authors: Ahmad Al-Omari, Osama Khreis, Ahmad M. K. Dagamseh, Abdullah Ababneh, Kevin Lear

Abstract:

High-speed infrared vertical-cavity surface-emitting laser diodes (VCSELs) with Cu-plated heat sinks were fabricated and tested. VCSELs with 10 mm aperture diameter and 4 mm of electroplated copper demonstrated a -3dB modulation bandwidth (f_-3dB) of 14 GHz and a resonance frequency (f_R) of 9.5 GHz at a bias current density (J_bias) of only 4.3 kA/cm², which corresponds to an improved f_-3dB²/J_bias ratio of 44 GHz²/kA/cm². At higher and lower bias current densities, the f_-3dB²/ J_bias ratio decreased to about 30 GHz²/kA/cm² and 18 GHz²/kA/cm², respectively. Examination of the analogue modulation response demonstrated that the presented VCSELs displayed a steady f_-3dB/ f_R ratio of 1.41±10% over the whole range of the bias current (1.3I_th to 6.2I_th). The devices also demonstrated a maximum modulation bandwidth (f_{-3dB max}) of more than 16 GHz at a bias current less than the industrial bias current standard for reliability by 25%.

Keywords: current density, high-speed VCSELs, modulation bandwidth, small-signal characteristics, thermal impedance, vertical-cavity surface-emitting lasers

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Authors: Gaoussou Doukoure Abdel Kader, Mnkandla Ernest

Abstract:

This research aims to investigate the usage of a personal software process oriented information system in order to facilitate the promotion of software quality and its improvement in organizations. In this light, at the term of a literature review on software quality and related concepts, the personal software process is discussed, more particularly in terms of software quality. Semi-structured interviews will be conducted with a team of software engineers on the first hand to establish a baseline on their understanding of what quality entails for them. The PSP methodology will then be presented to the engineers in its most basic aspects. The research will then proceed to practical case study where a PSP oriented information system is submitted to engineers for usage throughout their development process. Reports from the PSP information system as well as feedback from the engineers will be used in conjunction with the theoretical foundation to establish a PSP inspired framework for software quality promotion and improvement.

Keywords: information communication technology, personal software process, software quality, process quality, software engineering

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Authors: Bilal Tebboub, AmelLabbani

Abstract:

This article introduces a compact sensor based on high-transmission, high-sensitivity two-dimensional photonic crystals. The photonic crystal consists of a square network of silicon rods in the air. The sensor is composed of two waveguide couplers and a microcavity designed for monitoring the percentage of hydrogen in the air and identifying gas types. Through the Finite-Difference Time-Domain (FDTD) method, we demonstrate that the sensor's resonance wavelength is contingent upon changes in the gas refractive index. We analyze transmission spectra, quality factors, and sensor sensitivity. The sensor exhibits a notable quality factor and a sensitivity value of 1374 nm/RIU. Notably, the sensor's compact structure occupies an area of 74.5 μm2, rendering it suitable for integrated optical circuits.

Keywords: 2-D photonic crystal, sensitivity, F.D.T.D method, label-free biosensing

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Authors: S. Ghorbani, N. I. Polushin

Abstract:

In this study, an approach to identify factors affecting on surface roughness in a machining process is presented. This study is based on 81 data about surface roughness over a wide range of cutting tools (conventional, cutting tool with holes, cutting tool with composite material), workpiece materials (AISI 1045 Steel, AA2024 aluminum alloy, A48-class30 gray cast iron), spindle speed (630-1000 rpm), feed rate (0.05-0.075 mm/rev), depth of cut (0.05-0.15 mm) and tool overhang (41-65 mm). A single decision tree (SDT) analysis was done to identify factors for predicting a model of surface roughness, and the CART algorithm was employed for building and evaluating regression tree. Results show that a single decision tree is better than traditional regression models with higher rate and forecast accuracy and strong value.

Keywords: cutting condition, surface roughness, decision tree, CART algorithm

Procedia PDF Downloads 375