Search results for: memory effect

Authors: S. Wagner, C. Boley, Y. Forouzandeh

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When digging excavations, groundwater bearing layers are often encountered. In order to allow anhydrous excavation, soil groutings are carried out, which form a water-impermeable layer. As it is injected into groundwater areas, the effects of the materials used on the environment must be known. Developing an eco-friendly, economical and low viscous acrylic gel which has a sealing effect on groundwater is therefore a significant task. At this point the study begins. Basic investigations with the rheometer and a reverse column experiment have been performed with different mixing ratios of an acrylic gel. A dynamic rheology study was conducted to determine the time at which the gel still can be processed and the maximum gel strength is reached. To examine the effect of acrylic gel grouting on determine the parameters pH value, turbidity, electric conductivity, and total organic carbon on groundwater, an acrylic gel was injected in saturated sand filled the column. The structure was rinsed with a constant flow and the eluate was subsequently examined. The results show small changes in pH values and turbidity but there is a dependency between electric conductivity and total organic carbon. The curves of the two parameters react at the same time, which means that the electrical conductivity in the eluate can be measured constantly until the maximum is reached and only then must total organic carbon (TOC) samples be taken.

Keywords: acrylic gel grouting, dynamic rheology study, electric conductivity, total organic carbon

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Authors: Chayonnat Thanamun, Kreangkrai Maneeintr

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For petroleum industry, polymer flooding is the one of the main methods in enhanced oil recovery (EOR) that is used water-soluble polymer such as partially hydrolyzed polyacrylamide (HPAM) to increase oil production. It is added to the flooding water to improve the mobility ratio in the flooding process. During the polymer flooding process, water is produced as a by-product along with oil and gas production. This produced water is a mixture of inorganic and organic compound. Moreover, produced water is more difficult to treat than that from water flooding. In this work, the effect of HPAM residue on the wastewater treatment from polymer flooding is studied. Polyaluminium chloride (PAC) is selected to use as a flocculant. Therefore, the objective of this study is to evaluate the effect of polymer residues in produced water on the wastewater treatment by using PAC. The operating parameters of this study are flocculant dosage ranging from 300,400 and 500 mg/L temperature from 30-50 Celsius degree and HPAM concentrations from 500, 1000 and 2000 mg/L. Furthermore, the turbidity, as well as total suspended solids (TSS), are also studied. The results indicated that with an increase in HPAM concentration, the TSS and turbidity increase gradually with the increasing of coagulant dosage under the same temperature. Also, the coagulation-flocculation performance is improved with the increasing temperature. This can be applied to use in the wastewater treatment from oil production before this water can be injected back to the reservoir.

Keywords: wastewater treatment, petroleum production, polyaluminium chloride, polyacrylamide

Procedia PDF Downloads 132

Authors: Z. Mowafy Emam Mowafy, Ahmed R. Sayed, M. El Sayed Mohmmed Hassan

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Purpose: to evaluate the effect of low intensity laser on severe tinnitus in idiopathic sudden hearing loss patients. Methods of evaluation (Visual analogue scale and tinnitus handicap inventory scale):- Thirty patients who had unilateral tinnitus with sensorineural hearing loss were participated in the study. Subjects aged from 40 to 50 were randomly divided into two equal groups: group (A): composed of 15 patients who received the routine medical care (Systemic steroids) in addition to the low-intensity laser therapy (LILT) while group (B): composed of 15 patients who received only the routine medical care. Continuous 632.8nm He-Ne laser was used with 5mW power for 15 min\day, 3 days per week for 3 months. Results and conclusion: Results showed that application of the LILT had a valuable effect on severe tinnitus in idiopathic sudden hearing loss patients as evidenced by the highly decreased visual analogue scale and tinnitus handicap inventory scale.

Keywords: idiopathic sudden hearing loss, low intensity laser, tinnitus, tinnitus handicap inventory scale and visual analogue scale

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Authors: H. Babou, S. Ridjla, B. Amerate, R. Ferhoum, M. Aberkane

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This work is devoted to the experimental study of thermal ageing effect on the mechanical and micro structural behavior of polycarbonate (PC). A simple compression tests, micro hardness and an IRTF analysis were completed in order to characterize the response of material on specimens after ageing at a temperature of order 100 C° and for serval maintain duration 72, 144 and 216 hours. These investigations showed a decrease of the intrinsic properties of polycarbonate (Young modulus, yield stress, etc.); the superposition of spectra IRTF shows that the intensity of chemical connections C=C, C-O, CH3 and C-H are influenced by the duration of thermal ageing; in addition, an increase of 30 % of micro hardness was detected after 216 hour of ageing.

Keywords: amorphous polymer, polycarbonate, mechanical behavior, compression test, thermal ageing

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Authors: Emily Hamilton, Adiel Kahana, Ron Hauser, Shimi Barda

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BACKGROUND: In the male fertility and sperm bank unit of Tel Aviv Sourasky medical center, women are treated with intrauterine insemination (IUI) using washed sperm from their partner or thawed sperm from a selected donor. In most cases, the women perform the IUI treatment in Sourasky, but sometimes they ask to undergo the insemination procedure in another clinic with their own fertility doctor. In these cases, the sperm sample is prepared at the Sourasky lab and the patient is inseminated after arriving to her doctor. Our laboratory has previously found that time negatively affects several parameters of thawed sperm, and we estimate that it has more severe and significant effect than on washed sperm. AIM: To examine the effect of time on the quality of washed sperm versus thawed sperm. METHODS: Sperm samples were collected from men referred for semen analysis. Each ejaculate was allowed to liquefy for at least 20 min at 37°C and analyzed for sperm motility and vitality percentage and DNA fragmentation index (Time 0). Subsequently, 1ml of the sample was divided into two parts, 1st part was washed only and the 2nd part was washed, frozen and thawed. Time 1 analysis occurred immediately after sperm washing or thawing. Time 2 analysis occurred 75 minutes after time 1. Statistical analysis was performed using Student t-test. P values<0.05 were considered significant. RESULTS: Preliminary data showed that time had a greater impact on the average percentages of sperm motility and vitality in thawed compared to washed sperm samples (26%±10% vs. 21%±10% and 21%±9% vs. 9%±10%, respectively). An additional trend towards increased average DNA fragmentation percentage in thawed samples compared to washed samples was observed (46%±18% vs. 25%±24%). CONCLUSION: Time negatively effects sperm quality. The effect is greater in thawed samples compared to fresh samples.

Keywords: ART, male fertility, sperm cryopreservation, sperm quality

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Authors: Tahar Ghnaya, Majda Mnasri, Hanen Zaier, Rim Ghabriche, Chedly Abdelly

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It is known that the symbiotic association between plant and microorganisms are beneficial for plant growth and resistance to metal stress. Hence, it was demonstrated that Arbuscular mycorrhizal fungi have a positive effect on host plants growing in metal polluted soils. Legume plants are those which normally associate to rhizobacteria in order to fix atmospheric nitrogen. The aim of this work was to evaluate the effect this type of symbiosis on the tolerance and the accumulation of Cd. We chose Medicago sativa, as a modal for host legume plants and Rhizobium mililoti 2011 as rhizobial strain. Inoculated and non-inoculated plants of M. sativa were submitted during three month to 0, 50, and 100 mgCd/kg dry soil. Results showed that the presence of Cd in the medium induced, in both inoculated and non-inoculated plants, a chlorosis and necrosis. However, these symptoms were more pronounced in non-inoculated plants. The beneficial effect of inoculation of M. sativa with R. meliloti, on plant growth was confirmed by the measurement of biomass production which showed that the symbiotic association between host plant and rhizobacteria alleviates significantly Cd effect on biomass production, so inoculated plants produced more dry weight as compared to non-inoculated ones in the presence of all Cd tretments. On the other hand, under symbiosis conditions, Cd was more accumulated in different plant organs. Hence, in these plants, shoot Cd concentration reached 425 and it was 280 µg/gDW in non-inoculated ones in the presence of 100 ppm Cd. This result suggests that symbiosis enhances the absorption and translocation of Cd in this plant. In nodules and roots, we detected the highest Cd concentrations, demonstrating that these organs are able to concentrate Cd in their tissues. These data confirm that M. sataiva, cultivated in symbiosis with Rhizobium mililoti could be used in phytoextraction of Cd from contaminated soils.

Keywords: Cd, phytoremediation, Medicago sativa, Arbuscular mycorrhizal

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Authors: Şirin Küçük, Ayşe Kök, İsmail Şahin

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Mobile devices are very popular and useful tools for assisting people in daily life. With the advancement of mobile technologies, the issue of mobile learning has been widely investigated in education. Many researches consider that it is important to integrate pedagogical and technical strengths of mobile technology into learning environments. For this reason, the purpose of this research is to examine the effect of mobile technology use in education with meta-analysis method. Meta-analysis is a statistical technique which combines the findings of independent studies in a specific subject. In this respect, the articles will be examined by searching the databases for researches which are conducted between 2005 and 2014. It is expected that the results of this research will contribute to future research related to mobile technology use in education.

Keywords: mobile learning, meta-analysis, mobile technology, education

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Authors: Swapna Bhargavi Gantasala

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If teamwork is the key to organizational learning, productivity, and growth, then, why do some teams succeed in achieving these, while others falter at different stages? Building teams in higher education institutions has been a challenge and an open-ended constructivist approach was considered on an experimental basis for this study to address this challenge. For this research, teams of students from the MBA program were chosen to study the effect of teamwork in learning, the motivation levels among student team members, and the effect of collaboration in achieving team goals. The teams were built on shared vision and goals, cohesion was ensured, positive induction in the form of faculty mentoring was provided for each participating team and the results have been presented with conclusions and suggestions.

Keywords: teamwork, leadership, motivation and reinforcement, collaboration

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Authors: Mardiati Zain, Ryanto Khasrad, I. Elihasridas, J. Juliantoni

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The research objective was to determine the productivity of cattle fed a complete ration with ammoniated based of oil palm-frond supplemented by Rumen Microbes Growth Factor (RMGF). The research used Randomized Block Design applying 4 rations as treatment and 4 groups cattle. The treatments were: A (60% oil palm frond ammoniated + 40% concentrate + RMGF); B (50% oil palm frond ammoniated + 50% concentrate + RMGF); C (40% oil palm frond ammoniated + 60% concentrate + RMGF); and D (30% oil palm frond ammoniated + 70% concentrate + RMGF). The measured parameters were dry matter (DM) and organic matter (OM) intake, daily weight gain (DWG), feed efficiency, total digestible nutrient (TDN), and digestibility of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose, hemicellulose. Statistical analysis showed that the treatment had no significant effect (P > 0.05) on DM intake, OM intake, daily weight gain, feed efficiency, digestibility of DM, OM, CP, TDN, NDF, hemicellulose but had a highly significant effect (P < 0.01) on digestibility of ADF and cellulose. All treatments with different ratio (oil palm frond ammoniated: concentrate : RMGF) had no different effect on cattle productivities.

Keywords: oil palm frond ammoniated, digestibility, rumen microba growth factor, Bali cattle

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Authors: Bassam M. Abunahel, Nurul Zahirah Noor Azman, Munirah Jamil

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The effect of needle diameter on the morphological structure of electrospun n-Bi₂O₃/epoxy-PVA nanofibers has been investigated using three different types of needle diameters. The results were observed and investigated using two techniques of scanning electron microscope (SEM). The first technique is backscattered SEM while the second is secondary electron SEM. The results demonstrate that there is a correlation between the needle diameter and the morphology of electrospun nanofibers. As the internal needle diameter decreases, the average nanofiber diameter decreases and the fibers get thinner and smoother without agglomeration or beads formation. Moreover, with small needle diameter the nanofibrous porosity get larger compared with large needle diameter.

Keywords: needle diameter, fiber diameter, porosity, agglomeration

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Authors: Zohreh Rashmei

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Introduction: Plasma inactivation is one of the emerging technologies in biomedical field and has been applied to the inactivation of microorganisms in water. The inactivation effect has been attributed to the presence of active plasma species, i.e. OH, O, O3, H2O2, UV and electric fields, generated by the discharge of plasma. Material and Method: To evaluate germicidal effects of plasma, the electric spark discharge device was used. After the effect of the plasma samples were collected for culture medium agar plate count. In addition to biological experiments, the concentration of hydrogen peroxide was also measured. Results: The results showed that Plasma is able to inactivate a high concentration of E. coli. After a short period of plasma radiation on the surface of water, the amount log8 reduced the microbial load. Starting plasma radiation on the surface of the water, the measurements show of production and increasing the amount of hydrogen peroxide in water. So that at the end of the experiment, the concentration of hydrogen peroxide to about 100 mg / l increased. Conclusion: Increasing the concentration of hydrogen peroxide is directly related to the reduction of microbial load. The results of E. coli culture in media containing certain concentrations of H2O2 showed that E. coli can not to grow in a medium containing more than 2/5 mg/l of H2O2. Surely we can say that the main cause of killing bacteria is a molecule of H2O2.

Keywords: plasma, hydrogen peroxide, disinfection, E. coli

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Authors: Amir Wahid, Fazal Hadi, Amin Ullah Jan

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Tomato and Cauliflower seedlings were grown in-vitro under salt concentrations (0, 2, 4, 8, and 10 dSm-1) with objectives to investigate; (1) The effect of salinity on seedling growth and free proline production, (2) the correlation between seedling growth and proline contents, (3) comparative salt tolerance of both species. Different concentrations of salt showed considerable effect on percent (%) germination of seeds, length and biomass of shoot and root and also showed effect on percent water content of both plants seedlings. Germination rate in cauliflower was two times higher than tomato even at highest salt concentration (10 dSm-1). Seedling growth of both species was less effected at low salt concentrations (2 and 4 dSm-1) but at high concentrations (6 and 8 dSm-1) the seedling growth of both species was significantly decreased. Particularly the tomato root was highly significantly reduced. The proline level linearly increased in both species with increasing salt concentrations up-to 4 dSm-1 and then declined. The cauliflower showed higher free proline level than tomato under all salt treatments. Overall, the cauliflower seedlings showed better growth response along with higher proline contents on comparison with tomato seedlings.

Keywords: NaCl (Sodium Chloride), EC (Electrical Conductivity), MS (Murashig and Skoog), ANOVA (Analysis of Variance), LSD (Least Significant Differences)

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Authors: Ambuj Srivastava, Narender Singh

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This paper presents the effect of installation of cylindrical external store on the performance, stability, control and handling qualities of light transport category aircraft. A pair of long cylindrical store was installed symmetrically on either side of the fuselage (port and starboard) ahead of the wing and below the fuselage bottom surface running below pilot and co-pilot window. The cylindrical store was installed as hanging from aircraft surface through specially designed brackets. The adjoining structure was sufficiently reinforced for bearing aerodynamic loads. The length to diameter ratio of long cylindrical store was ~20. Based on academic studies and flow simulation analysis, a considerable detrimental effect on single engine second segment climb performance was found which was later validated through extensive flight testing exercise. The methodology of progressive flight envelope opening was adopted. The certification was sought from Regional airworthiness authorities and for according approval.

Keywords: second segment climb, maximum operating speed, cruise performance (single engine and twin engine), minimum control speed, and additional trim required

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Authors: Alireza Barari, Maryam Firozi-Niyaki, Maryam Kamarlouei

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Background: Herbs have a strong anti-cancer effect. Also, exercise is one of several lifestyle factors known to lower the risk of developing cancer. The aim of this study was to investigate the effect of endurance training and taxol on cyclooxygenase-2 and prostaglandin E2 in the liver tissue of mice with cervical cancer. Materials and Methods: In this experimental study, 35 female C57 mice were randomly divided into 5 groups (n=7 in each group): control (healthy), control (cancer), complement (cancer), training-supplementary (cancer) and training (cancer). The implantation of cancerous tumors was performed under the skin of the upper pelvis. The training group completed the endurance training protocol, which included 3 sessions per week, 50 minutes per session, at a speed of 14-18 m/s for six weeks. A dose of 60 mg/kg/day of pure taxol was injected intra peritoneally. The dependent variables of this study were measured 24 hours after the last training session by ELISA. Results: The results showed that the use of taxol and endurance training reduced the levels of cyclooxygenase-2 and prostaglandin E2 in the liver tissues of C57 mice with cervical cancer. Conclusion: Induction of the cancerous tissue in mice with cervical cancer increases the levels of cyclooxygenase-2 and prostaglandin E2 and endurance training along with taxol may reduce these levels.

Keywords: cervical cancer, taxol, endurance training, cyclooxygenase-2, prostaglandin E2

Procedia PDF Downloads 217

Authors: Joel Weymouth, Ramesh K. Karne, Alexander L. Wijesinha

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Bare Machine Internet is part of the Bare Machine Computing (BMC) paradigm. It is used in programming application ns to run directly on a device. It is software that runs directly against the hardware using CPU, Memory, and I/O. The software application runs without an Operating System and resident mass storage. An important part of the BMC paradigm is the Bare Machine Internet. It utilizes an Application Development model software that interfaces directly with the hardware on a network server and file server. Because it is “bare,” it is a powerful teaching and research tool that can readily display the internals of the network protocols, software, and hardware of the applications running on the Bare Server. It was also demonstrated that the bare server was accessible by laptop and by smartphone/android. The purpose was to show the further practicality of Bare Internet in Computer Engineering and Computer Science Education and Research. It was also to show that an undergraduate student could take advantage of a bare server with any device and any browser at any release version connected to the internet. This paper presents the Bare Web Server as an educational tool. We will discuss possible applications of this paradigm.

Keywords: bare machine computing, online research, network technology, visualizing network internals

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Authors: Motlatso Rampedi

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Nigeria has the fifth highest Total Fertility Rate in Sub-Saharan Africa at 5.5 children born to a woman. Some demographic research has found that there is an association between region of residence and fertility in Nigeria, with the Northern regions pertaining to high fertility and the Southern regions pertaining to low fertility levels. Even so, little attention has been given to understanding the effect of region of residence on fertility. Instead, a significant amount of research has been conducted on exploring the proximate determinants of fertility in Nigeria. The objective of this study was to test whether there is an association between region of residence and fertility in Nigeria. Using a sample size of 38 948 women aged 15-49 derived from the 2013 NDHS and the Poisson regression model for analysis, the study has found that region of residence has a significant effect on fertility. Moreover, the ANOVA test has shown that there is a socioeconomic disparity by region of residence in Nigeria. The Northern regions of Nigeria have shown to have higher levels of fertility as compared to the Southern regions. Therefore, while proximate determinants of fertility and socio-demographic characteristics of women are important, region of residence remains one of the fundamental determinants of fertility. Given these findings, it is recommended that government should not exhaust its resources or focus its fertility reduction policies and programmes at entire populations but target specific regions where fertility is most prevalent.

Keywords: high fertility, region, socioeconomic disparity, socio-demographic characteristics

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Authors: Marwa Hussein Mohamed, Mohamed Helmy Khafagy, Samah Ahmed Senbel

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Map Reduce is a programming model used to handle and support massive data sets. Rapidly increasing in data size and big data are the most important issue today to make an analysis of this data. map reduce is used to analyze data and get more helpful information by using two simple functions map and reduce it's only written by the programmer, and it includes load balancing , fault tolerance and high scalability. The most important operation in data analysis are join, but map reduce is not directly support join. This paper explains two-way map-reduce join algorithm, semi-join and per split semi-join, and proposes new algorithm hash semi-join that used hash table to increase performance by eliminating unused records as early as possible and apply join using hash table rather than using map function to match join key with other data table in the second phase but using hash tables isn't affecting on memory size because we only save matched records from the second table only. Our experimental result shows that using a hash table with hash semi-join algorithm has higher performance than two other algorithms while increasing the data size from 10 million records to 500 million and running time are increased according to the size of joined records between two tables.

Keywords: map reduce, hadoop, semi join, two way join

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Authors: Anand Kishore Kola, G. Uday Bhaskar Babu, Kotturi Ajay Kumar

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The modern dynamic systems used in industries are complex in nature and hence the fractional order controllers have been contemplated as a fresh approach to control system design that takes the complexity into account. Traditional integer order controllers use integer derivatives and integrals to control systems, whereas fractional order controllers use fractional derivatives and integrals to regulate memory and non-local behavior. This study provides a method based on the maximumsensitivity (Ms) methodology to discover all resilient fractional filter Internal Model Control - proportional integral derivative (IMC-PID) controllers that stabilize the closed-loop system and deliver the highest performance for a time delay system with a Smith predictor configuration. Additionally, it helps to enhance the range of PID controllers that are used to stabilize the system. This study also evaluates the effectiveness of the suggested controller approach for minimum phase system in comparison to those currently in use which are based on Integral of Absolute Error (IAE) and Total Variation (TV).

Keywords: modern dynamic systems, fractional order controllers, maximum-sensitivity, IMC-PID controllers, Smith predictor, IAE and TV

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Authors: Mahmoud A Rabah, Sabah M. Abelbasir

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Lead-calcium alloy containing up to 0.10% calcium was recovered from spent rechargeable sealed acid lead batteries. Two techniques were investigated to explore the effect of flux salts on the extent and quality of the recovered alloy, pyro-metallurgical and electrochemical methods. About 10 kg of the spent batteries were collected for testing. The sample was washed with hot water and dried. The plastic cases of the batteries were mechanically cut, and the contents were dismantled manually, the plastic containers were shredded for recycling. The electrode plates were freed from the loose powder and placed in SiC crucible and covered with alkali chloride salts. The loaded crucible was heated in an electronically controlled chamber furnace type Nabertherm C3 at temperatures up to 800 °C. The obtained metals were analyzed. The effect of temperature, rate of heating, atmospheric conditions, composition of the flux salts on the extent and quality of the recovered products were studied. Results revealed that the spent rechargeable batteries contain 6 blocks of 6 plates of Pb-Ca alloy each. Direct heating of these plates in a silicon carbide crucible under ambient conditions produces lead metal poor in calcium content ( < 0.07%) due to partial oxidation of the alloying calcium element. Rate of temperature increase has a considerable effect on the yield of the lead alloy extraction. Flux salts composition benefits the recovery process. Sodium salts are more powerful as compared to potassium salts. Lead calcium alloy meeting the standard specification was successfully recovered from the spent rechargeable acid lead batteries with a very competitive cost to the same alloy prepared from primary resources.

Keywords: rechargeable lead batteries, lead-calcium alloy, waste recovery, flux salts, thermal recovery

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Authors: Zhang Jun Xiong

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Objective: To explore the effect of physical exercise and outdoor lighting on the improvement of pupils' eyesight. Methods: A total of 208 first grade students in a primary school in Chengdu were enrolled in the study, 104 of whom were nearsighted and 104 had normal vision. They were randomly divided into indoor exercise group, outdoor exercise group, indoor control group and outdoor control group. Indoor and outdoor exercise groups performed moderate and high-intensity aerobic exercise three times a week, 60 minutes each time; The indoor and outdoor control groups had normal study and life during the experiment, without exercise intervention. The experiment lasted for one academic year, and the visual indicators of the subjects were tested before and after the experiment. Results: After the experiment, the visual fatigue index of the subjects with normal vision in the outdoor exercise group, indoor exercise group and outdoor control group decreased by 1.5 ± 2.89, 1.4 ± 3.05, 2.12 ± 2.66 respectively, and the diopter index decreased by 0.30D ± 0.09, 0.41D ± 0.16, 0.40D ± 0.19 respectively, while the visual fatigue score of the subjects with normal vision in the indoor control group increased by 2.3 ± 2.15, and the diopter decreased by 0.53D ± 0.22, There were significant differences in visual fatigue and diopter among the subjects with normal vision in each group (P<0.001). After the experiment, the visual fatigue index of the myopic subjects in the outdoor exercise group, indoor exercise group and outdoor control group decreased by 1.8 ± 1.95, 0.8 ± 1.81, 1.1 ± 1.85 respectively, and the diopter index decreased by 0.35D ± 0.21, 0.52D ± 0.24, 0.52D ± 0.15 respectively, while the visual fatigue score of the myopic subjects in the indoor control group increased by 1.3 ± 2.66, and the diopter decreased by 0.62D ± 0.29. There were significant differences between groups in visual fatigue and diopter (P<0.001). Conclusion: Both physical exercise and outdoor lighting can have a beneficial effect on children's vision, and the superposition effect of the two is better. It is suggested that outdoor physical exercise should be carried out more in primary school.

Keywords: physical exercise, outdoor lighting, pupil, vision, myopia

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Authors: Nureni A. Yekini, Isaac T. Babalola, Edwin E. Aighokhan, Agnes K. Akinwole, N. Stephen Igwe

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Survey was conducted to gather information on potential adverse health effects of Mobile Phones, and Telecommunication Tower Base Stations in Nigeria. Data was sourced from two sampled populations. Firstly from the people living in close proximity to base stations, and secondly from cell phone users. Questionnaire was used to gathered information from 574 people on thirteen non-specific health symptoms. Data obtained was presented and analyzed. The analysis shows that people living close to the based stations over a long period of time with or without cell phone, and also the heavy phone users with close proximity to the base stations are liable to have some potential health hazards, such as fatigue, sleep disturbances, headaches, feeling of discomfort, difficulty in concentrating, depression, memory loss, visual disruptions, irritability, hearing disruptions, skin problems, cardiovascular disorders, and dizziness.

Keywords: health hazards, wireless base stations, phone users, mobile phones, Nigeria

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Authors: Allouache Nadia

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Solid adsorption cooling machines have been extensively studied recently. They constitute very attractive solutions recover important amount of industrial waste heat medium temperature and to use renewable energy sources such as solar energy. The development of the technology of these machines can be carried out by experimental studies and by mathematical modelisation. This last method allows saving time and money because it is suppler to use to simulate the variation of different parameters. The adsorption cooling machines consist essentially of an evaporator, a condenser and a reactor (object of this work) containing a porous medium, which is in our case the activated carbon reacting by adsorption with ammoniac. The principle can be described as follows: When the adsorbent (at temperature T) is in exclusive contact with vapour of adsorbate (at pressure P), an amount of adsorbate is trapped inside the micro-pores in an almost liquid state. This adsorbed mass m, is a function of T and P according to a divariant equilibrium m=f (T,P). Moreover, at constant pressure, m decreases as T increases, and at constant adsorbed mass P increases with T. This makes it possible to imagine an ideal refrigerating cycle consisting of a period of heating/desorption/condensation followed by a period of cooling/adsorption/evaporation. Effect of key parameters on the machine performances are analysed and discussed.

Keywords: activated carbon-ammoniac pair, effect of key parameters, numerical modeling, solar cooling machine

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Authors: Ron Dick, P. S. D. V. Prasadarao, Glenn Coltman

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Agenesis of the corpus callosum (ACC) is a failure to develop corpus callosum - the large bundle of fibers of the brain that connects the two cerebral hemispheres. It can occur as a partial or complete absence of the corpus callosum. In the general population, its estimated prevalence rate is 1 in 4000 and a wide range of genetic, infectious, vascular, and toxic causes have been attributed to this heterogeneous condition. The diagnosis of ACC is often achieved by neuroimaging procedures. Though persons with ACC can perform normally on intelligence tests they generally present with a range of neuropsychological and social deficits. The deficit profile is characterized by poor coordination of motor movements, slow reaction time, processing speed and, poor memory. Socially, they present with deficits in communication, language processing, the theory of mind, and interpersonal relationships. The present paper illustrates the role of neuropsychological assessment with implications to psychosocial management in a case of agenesis of the corpus callosum. Method: A 27-year old left handed Caucasian male with a history of ACC was self-referred for a neuropsychological assessment to assist him in his employment options. Parents noted significant difficulties with coordination and balance at an early age of 2-3 years and he was diagnosed with dyspraxia at the age of 14 years. History also indicated visual impairment, hypotonia, poor muscle coordination, and delayed development of motor milestones. MRI scan indicated agenesis of the corpus callosum with ventricular morphology, widely spaced parallel lateral ventricles and mild dilatation of the posterior horns; it also showed colpocephaly—a disproportionate enlargement of the occipital horns of the lateral ventricles which might be affecting his motor abilities and visual defects. The MRI scan ruled out other structural abnormalities or neonatal brain injury. At the time of assessment, the subject presented with such problems as poor coordination, slowed processing speed, poor organizational skills and time management, and difficulty with social cues and facial expressions. A comprehensive neuropsychological assessment was planned and conducted to assist in identifying the current neuropsychological profile to facilitate the formulation of a psychosocial and occupational rehabilitation programme. Results: General intellectual functioning was within the average range and his performance on memory-related tasks was adequate. Significant visuospatial and visuoconstructional deficits were evident across tests; constructional difficulties were seen in tasks such as copying a complex figure, building a tower and manipulating blocks. Poor visual scanning ability and visual motor speed were evident. Socially, the subject reported heightened social anxiety, difficulty in responding to cues in the social environment, and difficulty in developing intimate relationships. Conclusion: Persons with ACC are known to present with specific cognitive deficits and problems in social situations. Findings from the current neuropsychological assessment indicated significant visuospatial difficulties, poor visual scanning and problems in social interactions. His general intellectual functioning was within the average range. Based on the findings from the comprehensive neuropsychological assessment, a structured psychosocial rehabilitation programme was developed and recommended.

Keywords: agenesis, callosum, corpus, neuropsychology, psychosocial, rehabilitation

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Authors: K. P. Shinde, M. V. Tien, H. Lin, H.-R. Park, S.-C.Yu, K. C. Chung, D.-H. Kim

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Magnetic refrigeration provides an attractive alternative cooling technology due to its potential advantages such as high cooling efficiency, environmental friendliness, low noise, and compactness over the conventional cooling techniques based on gas compression. Magnetocaloric effect (MCE) occurs by changes in entropy (ΔS) and temperature (ΔT) under external magnetic fields. We have been focused on identifying materials with large MCE in two temperature regimes, not only room temperature but also at cryogenic temperature for specific technological applications, such as space science and liquefaction of hydrogen in fuel industry. To date, the commonly used materials for cryogenic refrigeration are based on hydrated salts. In the present work, we report giant MCE in rare earth Ho2O3 nanopowder at cryogenic temperature. HoN nanoparticles with average size of 30 nm were prepared by using plasma arc discharge method with gas composition of N2/H2 (80%/20%). The prepared HoN was sintered in air atmosphere at 1200 oC for 24 hrs to convert it into oxide. Structural and morphological properties were studied by XRD and SEM. XRD confirms the pure phase and cubic crystal structure of Ho2O3 without any impurity within error range. It has been discovered that Holmium oxide exhibits giant MCE at low temperature without magnetic hysteresis loss with the second-order antiferromagnetic phase transition with Néels temperature around 2 K. The maximum entropy change was found to be 25.2 J/kgK at an applied field of 6 T.

Keywords: magnetocaloric effect, Ho₂O₃, magnetic entropy change, nanopowder

Procedia PDF Downloads 134

Authors: V. Veena, Suguna Yesodharan, E. P. Yesodharan

Abstract:

Two Advanced Oxidation Processes (AOP) i.e., sono- and photo-catalysis mediated by semiconductor oxide catalyst, ZnO has been found effective for the removal of trace amounts of the toxic dye pollutant Indigocarmine (IC) from water. The effect of various reaction parameters such as concentration of the dye, catalyst dosage, temperature, pH, dissolved oxygen etc. as well as the addition of oxidisers and presence of salts in water on the rate of degradation has been evaluated and optimised. The degradation follows variable kinetics depending on the concentration of the substrate, the order of reaction varying from 1 to 0 with increase in concentration. The reaction proceeds through a number of intermediates and many of them have been identified using GCMS technique. The intermediates do not affect the rate of degradation significantly. The influence of anions such as chloride, sulphate, fluoride, carbonate, bicarbonate, phosphate etc. on the degradation of IC is not consistent and does not follow any predictable pattern. Phosphates and fluorides inhibit the degradation while chloride, sulphate, carbonate and bicarbonate enhance. Adsorption studies of the dye in the absence as well as presence of these anions show that there may not be any direct correlation between the adsorption of the dye on the catalyst and the degradation. Oxidants such as hydrogen peroxide and persulphate enhance the degradation though the combined effect and it is less than the cumulative effect of individual components. COD measurements show that the degradation proceeds to complete mineralisation. The results will be presented and probable mechanism for the degradation will be discussed.

Keywords: AOP, COD, indigocarmine, photocatalysis, sonocatalysis

Procedia PDF Downloads 318

Authors: Mohammed Mahmood, Walid Tizani, Carlo Sansour

Abstract:

In this paper, experimental testing and numerical analysis were used to investigate the effect of tube thickness on the face bending for concrete filled hollow sections connected to other structural members using Extended Hollobolts. Six samples were tested experimentally by applying pull-out load on the bolts. These samples were designed to fail by column face bending. The main variable in all tests is the column face thickness. Finite element analyses were also performed using ABAQUS 6.11 to extend the experimental results and to quantify the effect of column face thickness. Results show that, the column face thickness has a clear impact on the connection strength and stiffness. However, the amount of improvement in the connection stiffness by changing the column face thickness from 5 mm to 6.3 mm seems to be higher than that when increasing it from 6.3 mm to 8 mm. The displacement at which the bolts start pulling-out from their holes increased with the use of thinner column face due to the high flexibility of the section. At the ultimate strength, the yielding of the column face propagated to the column corner and there was no yielding in its walls. After the ultimate resistance is reached, the propagation of the yielding was mainly in the column face with a miner yielding in the walls.

Keywords: anchored bolted connection, Extended Hollobolt, column faces bending, concrete filled hollow sections

Procedia PDF Downloads 408

Authors: Amin Chegenizadeh, Mahdi Keramatikerman, Hamid Nikraz

Abstract:

Pavement engineering plays a significant role to develop cost effective and efficient highway and road networks. In general, pavement regarding structure is categorized in two core group namely flexible and rigid pavements. There are various benefits in application of rigid pavement. For instance, they have a longer life and lower maintenance costs in compare with the flexible pavement. In rigid pavement designs, temperature and thickness are two effective parameters that could widely affect the total cost of the project. In this study, a numerical modeling using Kenpave-Kenslab was performed to investigate the effect of these two important parameters in the rigid pavement.   

Keywords: rigid pavement, Kenpave, Kenslab, thickness, temperature

Procedia PDF Downloads 350

Authors: Wasim Orfali, Hesham Tolba

Abstract:

This research investigates the acoustical characteristics of Al-Madinah Holy Mosque. Extensive field measurements were conducted in different locations of Al-Madinah Holy Mosque to characterize its acoustic characteristics. The acoustical characteristics are usually evaluated by the use of objective parameters in unoccupied rooms due to practical considerations. However, under normal conditions, the room occupancy can vary such characteristics due to the effect of the additional sound absorption present in the room or by the change in signal-to-noise ratio. Based on the acoustic measurements carried out in Al-Madinah Holy Mosque with and without occupancy, and the analysis of such measurements, the existence of acoustical deficiencies has been confirmed.

Keywords: Al-Madinah Holy Mosque, mosque acoustics, speech intelligibility, worship sound

Procedia PDF Downloads 158

Authors: Ararat Khachatryan, Davit Mirzoyan

Abstract:

In sub micrometer technology, the aging phenomenon starts to have a significant impact on the reliability of integrated circuits by bringing performance degradation. For that reason, it is important to have a capability to evaluate the aging effects accurately. This paper presents an accurate aging measurement approach based on phase-locked loop (PLL) and voltage-controlled oscillator (VCO) circuit. The architecture is rejecting the circuit self-aging effect from the characteristics of PLL, which is generating the frequency without any aging phenomena affects. The aging monitor is implemented in low power 32 nm CMOS technology, and occupies a pretty small area. Aging simulation results show that the proposed aging measurement circuit improves accuracy by about 2.8% at high temperature and 19.6% at high voltage.

Keywords: aging effect, HCI, NBTI, nanoscale

Procedia PDF Downloads 345

Authors: Nurlaili Syafar Wulan, Almurdi, Suprianto Kosno

Abstract:

Introduction: Periodontitis defined as an inflammatory disease of teeth supporting tissue with irritation of specific pathogens as the main aetiology. Periodontitis can be cured by giving medical action accompanied by administration of an antibiotic, but the use of antibiotic has a side effect that can cause bacterial resistance. This side effect can be corrected by probiotic, which has antibiotic-like substance but do not have bacterial resistance effect; it makes probiotic became a promising future periodontitis medication. West Sumatran people has their own typical traditional food product made from fermented buffalo’s milk called dadih, and it contained probiotics. Objectives: The aim of this study was to determine the ability of probiotic Pediococcus pentosaceus isolated from dadih in inhibiting the growth of bacteria Aggregatibacter actinomycetemcomitans. Material and Method: This was a true experimental study with post-test and control group design. This study was conducted on 36 samples of 2 treatment groups, the test group with probiotic Pediococcus pentosacesus isolated from dadih and the negative control group with sterile aquadest. The antibacterial effect was tested using the Kirby-Bauer disk diffusion method and calculated by measuring the zone of inhibition on MHA around paper disk using a sliding caliper with 0.5 mm accuracy. Result: The result of bivariate analysis using Independent t-test was p=0.00 where p < 0.05 means that there is a significant difference between the tested group and negative control group. Conclusion: Probiotic Pediococcus pentosaceus isolated from dadih are able to inhibit the growth of Aggregatibacter actinomycetemcomitans.

Keywords: aggregatibacter actinomycetemcomitans, antibacterial activities, periodontitis, probiotic Pediococcus pentosaceus

Procedia PDF Downloads 119