Search results for: clotting time test

Authors: A. C. Kumbharkhane

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Time domain dielectric relaxation microwave spectroscopy (TDRMS) is a term used to describe a technique of observing the time dependant response of a sample after application of time dependant electromagnetic field. A TDRMS probes the interaction of a macroscopic sample with a time dependent electrical field. The resulting complex permittivity spectrum, characterizes amplitude (voltage) and time scale of the charge-density fluctuations within the sample. These fluctuations may arise from the reorientation of the permanent dipole moments of individual molecules or from the rotation of dipolar moieties in flexible molecules, like polymers. The time scale of these fluctuations depends on the sample and its relative relaxation mechanism. Relaxation times range from some picoseconds in low viscosity liquids to hours in glasses, Therefore the TDRS technique covers an extensive dynamical process. The corresponding frequencies range from 10-4 Hz to 1012 Hz. This inherent ability to monitor the cooperative motion of molecular ensemble distinguishes dielectric relaxation from methods like NMR or Raman spectroscopy, which yield information on the motions of individual molecules. Recently, we have developed and established the TDR technique in laboratory that provides information regarding dielectric permittivity in the frequency range 10 MHz to 30 GHz. The TDR method involves the generation of step pulse with rise time of 20 pico-seconds in a coaxial line system and monitoring the change in pulse shape after reflection from the sample placed at the end of the coaxial line. There is a great interest to study the dielectric relaxation behaviour in liquid systems to understand the role of hydrogen bond in liquid system. The intermolecular interaction through hydrogen bonds in molecular liquids results in peculiar dynamical properties. The dynamics of hydrogen-bonded liquids have been studied. The theoretical model to explain the experimental results will be discussed.

Keywords: microwave, time domain reflectometry (TDR), dielectric measurement, relaxation time

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Authors: Mahmood Dehqan, Peyman Peyvasteh

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In recent years there has been a growing interest in issues concerning the impact of sociocultural theory (SCT) of learning on different aspects of second/foreign language learning. This study aimed to find the possible effects of sociocultural teaching techniques on reading strategy of EFL learners. Indeed, the present research compared the impact of peer and teacher scaffolding on EFL learners’ reading strategy use across two proficiency levels. To this end, a pre-test post-test quasi-experimental research design was used and two instruments were utilized to collect the data: Nelson English language test and reading strategy questionnaire. Ninety five university students participated in this study were divided into two groups of teacher and peer scaffolding. Teacher scaffolding group received scaffolded help from the teacher based on three mechanisms of effective help within ZPD: graduated, contingent, dialogic. In contrast, learners of peer scaffolding group were unleashed from the teacher-fronted classroom as they were asked to carry out the reading comprehension tasks with the feedback they provided for each other. Results obtained from ANOVA revealed that teacher scaffolding group outperformed the peer scaffolding group in terms of reading strategy use. It means teacher’s scaffolded help provided within the learners’ ZPD led to better reading strategy improvement compared with the peer scaffolded help. However, the interaction effect between proficiency factor and teaching technique was non-significant, leading to the conclusion that strategy use of the learners was not affected by their proficiency level in either teacher or peer scaffolding groups.

Keywords: peer scaffolding, proficiency level, reading strategy, sociocultural theory, teacher scaffolding

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Authors: Gurjinder Singh, Ankur Gill, Amardeep Singh Kang

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In the present work an effort has been made to study the influence of the welding parameters on tensile strength of friction stir welding of aluminum. Three process parameters tool rotation speed, welding speed, and shoulder diameter were selected for the study. Two level factorial design of eight runs was selected for conducting the experiments. The mathematical model was developed from the data obtained. The significance of coefficients and adequacy of developed models were tested by ‘t’ test and ‘F’ test respectively. The effects of process parameters on mechanical properties have been represented in the form of graphs for better understanding.

Keywords: friction stir welding, aluminium alloy, mathematical model, welding speed

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Authors: Z. Balak, M. Zakeri, M.R.Rahimipur, M. Azizieh

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Spark Plasma Sintering is a new technique which was used for ultra high temperature ceramics such as ZrB2-based composites in recent years. Taguchi design was applied to explore effective parameters for achieving the highest hardness. Nine factors including SiC, Cf, MoSi2, HfB2 and ZrC content, milling time of Cf and SPS parameters such as temperature, time and pressure in four levels were considered through the Taguchi technique. In this study, only the effect of SPS conditions on densification and hardness were investigated. ZrB2-based composites were prepared by SPS in different temperatures (1600°C,1700°C, 1800°C, 1900°C), times (4min, 8 min, 12 min, 16min) and pressures (10MPa, 20MPa, 30MPa and 40MPa). The effect of SPS parameters on the densification and hardness were investigated. It was found, by increasing the temperature and time, from level 1 to 4, densification improved continuously. Also, the results shows hardness increases continuously by increasing temperature and time. Finally, it is concluded that temperature and time have more significant effect on densification and harness rather than pressure.

Keywords: spark plasma sintering (SPS), ultra high temperature ceramics (UHTCs), densification, hardness

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Authors: Manoj M. Sarode, Sharad P. Jadhav, Mukesh D. Patil, Pushparaj S. Suryawanshi

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Even though the PID controller is widely used in industrial process, tuning of PID parameters are not easy. It is a time consuming and requires expert people. Another drawback of PID controller is that process dynamics might change over time. This can happen due to variation of the process load, normal wear and tear etc. To compensate for process behavior change over time, expert users are required to recalibrate the PID gains. Implementation of model based controllers usually needs a process model. Identification of process model is time consuming job and no guaranty of model accuracy. If the identified model is not accurate, performance of the controller may degrade. Model based controllers are quite expensive and the whole procedure for the implementation is sometimes tedious. To eliminate such issues Autotuning PID controller becomes vital element. Software based Relay Feedback Autotuning Controller proves to be efficient, upgradable and maintenance free controller. In Relay Feedback Autotune controller PID parameters can be achieved with a very short span of time. This paper presents the real time implementation of LabVIEW based Relay Feedback Autotuning PID controller. It is successfully developed and implemented to control level of a laboratory setup. Its performance is analyzed for different setpoints and found satisfactorily.

Keywords: autotuning, PID, liquid level control, recalibrate, labview, controller

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Authors: Reza Ziaie Moayad, Azam Kouhpeyma

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In-situ testing is preferred to evaluate the liquefaction potential in cohesionless soils due to high disturbance during sampling. Although new in-situ methods with high accuracy have been developed, standard penetration test, the simplest and the oldest in-situ test, is still used due to the profusion of the recorded data. This paper reviews the Iranian standard of evaluating liquefaction potential in soils (codes 525) and compares the liquefaction assessment methods based on SPT results on cohesionless soil in this standard with the international standards. To this, methods for assessing liquefaction potential which are presented by Cetin et al. (2004), Boulanger and Idriss (2014) are compared with what is presented in standard 525. It is found that although the procedure used in Iranian standard of evaluating the potential of liquefaction has not been updated according to the new findings, it is a conservative procedure.

Keywords: cohesionless soil, liquefaction, SPT, standard 525

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Authors: M. S. Maglasang, S. O. Palacio, L. P. Ogdoc

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Business Process Outsourcing has been one of the fastest growing and emerging industry in the Philippines today. Unlike most of the contact service centers, more popularly known as "call centers", The BPO Industry’s primary outsourced service is performing audits of the global clients' logistics. As a service industry, manpower is considered as the most important yet the most expensive resource in the company. Because of this, there is a need to maximize the human resources so people are effectively and efficiently utilized. The main purpose of the study is to optimize the current manpower resources through effective distribution and assignment of different types of bills to the different skill-level of data entry operators. The assignment model parameters include the average observed time matrix gathered from through time study, which incorporates the learning curve concept. Subsequently, a simulation model was made to duplicate the arrival rate of demand which includes the different batches and types of bill per day. Next, a mathematical linear programming model was formulated. Its objective is to minimize direct labor cost per bill by allocating the different types of bills to the different skill-levels of operators. Finally, a hypothesis test was done to validate the model, comparing the actual and simulated results. The analysis of results revealed that the there’s low utilization of effective capacity because of its failure to determine the product-mix, skill-mix, and simulated demand as model parameters. Moreover, failure to consider the effects of learning curve leads to overestimation of labor needs. From 107 current number of operators, the proposed model gives a result of 79 operators. This results to an increase of utilization of effective capacity to 14.94%. It is recommended that the excess 28 operators would be reallocated to the other areas of the department. Finally, a manpower capacity planning model is also recommended in support to management’s decisions on what to do when the current capacity would reach its limit with the expected increasing demand.

Keywords: optimization modelling, linear programming, simulation, time and motion study, capacity planning

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Authors: Yanqi Yang, Chongshan Liao, Cheuk Hin Ho, Susan Bridges

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Aim: To investigate student’s perceptions of using e-models in an inquiry-based curriculum. Approach: 52 second-year dental students completed a pre- and post-test questionnaire relating to their perceptions of e-models and their use in inquiry-based learning. The pre-test occurred prior to any learning with e-models. The follow-up survey was conducted after one year's experience of using e-models. Results: There was no significant difference between the two sets of questionnaires regarding student’s perceptions of the usefulness of e-models and their willingness to use e-models in future inquiry-based learning. Most of the students preferred using both plaster models and e-models in tandem. Conclusion: Students did not change their attitude towards e-models and most of them agreed or were neutral that e-models are useful in inquiry-based learning. Whilst recognizing the utility of 3D models for learning, student's preference for combining these with solid models has implications for the development of haptic sensibility in an operative discipline.

Keywords: e-models, inquiry-based curriculum, education, questionnaire

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Authors: Andrée-Anne Parent, Alain-Steve Comtois

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The Antarctica environment can be a great challenge for human exploration. Explorers need to be focused on the task and require the physical abilities to succeed and survive in complete autonomy in this hostile environment. The aim of this study was to observe cognitive performance and physiological stress with a biomarker (cortisol) and hand grip strength during an expedition in Antarctica. A total of 6 explorers were in complete autonomous exploration on the Forbidden Plateau in Antarctica to reach unknown summits during a 30 day period. The Stroop Test, a simple reaction time, and mood scale (PANAS) tests were performed every week during the expedition. Saliva samples were taken before sailing to Antarctica, the first day on the continent, after the mission on the continent and on the boat return trip. Furthermore, hair samples were taken before and after the expedition. The results were analyzed with SPSS using ANOVA repeated measures. The Stroop and mood scale results are presented in the following order: 1) before sailing to Antarctica, 2) the first day on the continent, 3) after the mission on the continent and 4) on the boat return trip. No significant difference was observed with the Stroop (759±166 ms, 850±114 ms, 772±179 ms and 833±105 ms, respectively) and the PANAS (39.5 ±5.7, 40.5±5, 41.8±6.9, 37.3±5.8 positive emotions, and 17.5±2.3, 18.2±5, 18.3±8.6, 15.8±5.4 negative emotions, respectively) (p>0.05). However, there appears to be an improvement at the end of the second week. Furthermore, the simple reaction time was significantly lower at the end of the second week, a moment where important decisions were taken about the mission, vs the week before (416±39 ms vs 459.8±39 ms respectively; p=0.030). Furthermore, the saliva cortisol was not significantly different (p>0.05) possibly due to important variations and seemed to reach a peak on the first day on the continent. However, the cortisol from the hair pre and post expedition increased significantly (2.4±0.5 pg/mg pre-expedition and 16.7±9.2 pg/mg post-expedition, p=0.013) showing important stress during the expedition. Moreover, no significant difference was observed on the grip strength except between after the mission on the continent and after the boat return trip (91.5±21 kg vs 85±19 kg, p=0.20). In conclusion, the cognitive performance does not seem to be affected during the expedition. Furthermore, it seems to increase for specific important events where the crew seemed to focus on the present task. The physiological stress does not seem to change significantly at specific moments, however, a global pre-post mission measure can be important and for this reason, for long-term missions, a pre-expedition baseline measure is important for crewmembers.

Keywords: Antarctica, cognitive performance, expedition, physiological adaptation, reaction time

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Authors: Mohamad Nizam Asmuni, Ahmad Naszeri Salleh, Yunus Adam, Azhar Yaacob, Mohd Hafiz Rosli, Muhamad Nazrul Hakim Abdullah

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Athletes at the school should have good physical fitness to participate in tournament. Currently, there are no standards for the level of physical fitness for MARA Junior Science Collage (MJSC). Therefore, this research is to determine the level of physical fitness of rugby player at MJSC. A total of 62 samples (age 16.4 ± 0.75) among rugby players at MJSC were randomly selected to participate in this study. Height, weight, body fat percentage, body mass index (BMI) and other physical testing are measured and recorded. The results showed that the average of body mass index (BMI) for rugby players is 23.4 ± 4:51. Body mass index (BMI) of rugby players can be categorized as pre-obese based on World Health Organization (WHO) guidelines. BMI for rugby players was categorized as healthy based on body fat ranges for standard adults at NY Obesity Research Center. Bleep test results show that the average Bleep test is level 7 and shuttle 5; average VO2max was 37.94 L/min. Physical fitness and performance of rugby players at MJSC is lower compared to the rugby junior athletes in University Putra Malaysia (UPM). Therefore, physical fitness of rugby players must be improved to ensure the rugby players at MJSC could be performs better in the tournament.

Keywords: physical fitness, MARA junior science collage (MJSC), body mass index (BMI), bleep test

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Authors: Siyamak Sarafraz, Reza Esmaeil Pour, Saeed Jamshidi, Asghar Molaei Dehkordi

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Cutting transport is one of the major problems in directional and extended reach oil and gas wells. Lack of sufficient attention to this issue may bring some troubles such as casing running, stuck pipe, excessive torque and drag, hole pack off, bit wear, decreased the rate of penetration (ROP), increased equivalent circulation density (ECD) and logging. Since it is practically impossible to directly observe the behavior of deep wells, a test setup was designed to investigate cutting transport phenomena. This experimental work carried out to scrutiny behavior of the effective variables in cutting transport. The test setup contained a test section with 17 feet long that made of a 3.28 feet long transparent glass pipe with 3 inch diameter, a storage tank with 100 liters capacity, drill pipe rotation which made of stainless steel with 1.25 inches diameter, pump to circulate drilling fluid, valve to adjust flow rate, bit and a camera to record all events which then converted to RGB images via the Image Processing Toolbox. After preparation of test process, each test performed separately, and weights of the output particles were measured and compared with each other. Observation charts were plotted to assess the behavior of viscosity, flow rate and RPM in inclinations of 0°, 30°, 60° and 90°. RPM was explored with other variables such as flow rate and viscosity in different angles. Also, effect of different flow rate was investigated in directional conditions. To access the precise results, captured image were analyzed to find out bed thickening and particles behave in the annulus. The results of this experimental study demonstrate that drill string rotation helps particles to be suspension and reduce the particle deposition cutting movement increased significantly. By raising fluid velocity, laminar flow converted to turbulence flow in the annulus. Increases in flow rate in horizontal section by considering a lower range of viscosity is more effective and improved cuttings transport performance.

Keywords: cutting transport, directional drilling, flow rate, hole cleaning, pipe rotation

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Authors: Shizrah Jamal, Robia Ghafoor, Farhan Raza

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Porcelain fused to metal crown is the most versatile variety of crown that is commonly placed worldwide. Various complications have been reported in the PFM crowns with use over the period of time. These include chipping of the porcelain, recurrent caries, loss of retention, open contacts, and tooth fracture. The objective of the present study was to determine the frequency of these complications in crowns cemented over a period of five years in a tertiary care hospital and also to report the survival of these crowns. A retrospective study was conducted in Dental clinics, Aga Khan University Hospital in which 150 PFM crowns cemented over a period of five years were evaluated. Patient demographics, oral hygiene habits, para-functional habits, crown insertion and follow-up dates were recorded in a specially designed proforma. All PFM crowns fulfilling the inclusion criteria were assessed both clinically and radiographically for the presence of any complication. SPSS version 22.0 was used for statistical analysis. Frequency distribution and proportion of complications were determined. Chi-square test was used to determine the association of complications of PFM crowns with multiple variables including tooth wear, opposing dentition and betel nut chewing. Kaplan- meier survival analysis was used to determine the survival of PFM crowns over the period of five years. Level of significance was kept at 0.05. A total of 107 patients, with a mean age of 43.51 + 12.4 years, having 150 PFM crowns were evaluated. The most common complication observed was open proximal contacts (8.7%) followed by porcelain chipping (6%), decementation (5.3%), and abutment fracture (1.3%). Chi square test showed that there was no statistically significant association of PFM crown complication with tooth wear, betel nut and opposing dentition (p-value <0.05). The overall success and survival rates of PFM crowns turned out to be 78.7 and 84.7% respectively. Within the limitations of the study, it can be concluded that PFM crowns are an effective treatment modality with high success and survival rates. Since it was a single centered study; the results should be generalized with caution.

Keywords: chipping, complication, crown, survival rate

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Authors: Houda Abadlia, Nadia Smairi, Khaled Ghedira

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Multiobjective Particle Swarm Optimization (MOPSO) has shown an effective performance for solving test functions and real-world optimization problems. However, this method has a premature convergence problem, which may lead to lack of diversity. In order to improve its performance, this paper presents a hybrid approach which embedded the MOPSO into the island model and integrated a local search technique, Variable Neighborhood Search, to enhance the diversity into the swarm. Experiments on two series of test functions have shown the effectiveness of the proposed approach. A comparison with other evolutionary algorithms shows that the proposed approach presented a good performance in solving multiobjective optimization problems.

Keywords: particle swarm optimization, migration, variable neighborhood search, multiobjective optimization

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Authors: Leila Karshenas, Hamid Reza Khodaei, Behnaz Mahdavi

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We know that nitric oxide (NO) plays an important role in all sexual activities of animals. It is made in body from NO synthase enzyme and L-arginin molecule. NO can bound with sulfur-iron complexes and because production of steroid sexual hormones is related to enzymes which have this complex, NO can change the activity of these enzymes. NO affects many cells including endothelial cells of veins, macrophages and mast cells. These cells are found in testis leydig cells and therefore are important source of NO in testis tissue. Minimizing damages to sperm at the time of sperm freezing and thawing is really important. The goal of this study was to determine the function of NO before freezing and its effects on quality and viability of sperms after thawing and incubation. 4 Holstein bulls were selected from the age of 4, and artificial insemination was done for 3 weeks (2 times a week). Treatments were 0, 10, 50 and 100 nm of sodium nitroprusside (SNP). Data analysis was performed by SAS98 program. Also, mean comparison was done using Duncan's multiple ranges test (P<0.05). Concentrations used was found to increase motility and viability of spermatozoa at 1, 2 and 3 hours after thawing significantly (P<0.05), but there was no significant difference at zero time. SNP levels reduced the amount of lipid peroxidation in sperm membrane, increased acrosome health and improved sample membranes especially in 50 and 100 nm treatments. According to results, adding SNP to semen diluents increases motility and viability of spermatozoa. Also, it reduces lipid peroxidation in sperm membrane and improves sperm function.

Keywords: sperm motility, nitric oxide, lipid peroxidation, spermatozoa

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Authors: Keunhong Chae, Seokho Yoon

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This paper proposes a cooperative Alamouti space time transmission scheme with low relay complexity for the cooperative communication systems. In the proposed scheme, the source node combines the data symbols to construct the Alamouti-coded form at the destination node, while the conventional scheme performs the corresponding operations at the relay nodes. In simulation results, it is shown that the proposed scheme achieves the second order cooperative diversity while maintaining the same bit error rate (BER) performance as that of the conventional scheme.

Keywords: Space-time transmission, cooperative communication system, MIMO.

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Authors: Taha Zakaraia Abdel Wahid

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In the present study, a development of the papers is introduced. The behavior of the unsteady non-equilibrium distribution functions for a rarefied gas mixture under the effect of non-linear thermal radiation field is presented. For the best of our knowledge this is done for the first time at all. The distinction and comparisons between the unsteady perturbed and the unsteady equilibrium velocity distribution functions are illustrated. The equilibrium time for the rarefied gas mixture is determined for the first time. The non-equilibrium thermodynamic properties of the system is investigated. The results are applied to the Argon-Neon binary gas mixture, for various values of both of molar fraction parameters and radiation field intensity. 3D-Graphics illustrating the calculated variables are drawn to predict their behavior and the results are discussed.

Keywords: radiation field, binary gas mixture, exact solutions, travelling wave method, unsteady BGK model, irreversible thermodynamics

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Authors: Kübra Yüzüncüyıl, Aytekin İşman, Berkay Buluş

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In the last quarter of the 20th century, Food Studies was emerged as an interdisciplinary program. It seeks to develop a critical perspective on sociocultural meanings of food. The notion of food has been related with certain social and cultural values throughout history. In today’s society, with the rise of new media technologies, cultural structure have been digitized. Food culture in this main, is also endowed with digital codes. In particular, social media has been integrated into foodways. This study attempts to examine the gratifications that individuals obtain from social media use on foodways. In the first part of study, the relationship between food culture and digital culture is examined. Secondly, theoretical framework and research method of the study are explained. In order to achieve the particular aim of study, Uses and Gratifications Theory is adopted as conceptual framework. Conventional gratification categories are redefined in new media terms. After that, the relation between redefined categories and foodways is uncovered. Due to its peculiar context, this study follows a quantitative research method. By conducting pre-interviews and factor analysis, a peculiar survey is developed. The sample of study is chosen among 405 undergraduate communication faculty students of Sakarya University by proportionate stratification sampling method. In the analysis of the collected data, statistical methods One-Way ANOVA, Independent Samples T-test, and Tuckey Honest Significant Difference Test, Post Hoc Test are used.

Keywords: food studies, food communication, new media, communication

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Authors: K. Senthil Kumar, A. Vasumalaikannan

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In this paper, teleoperation of the quadrotor using Internet with Force feedback is addressed. Teleoperation with Force feedback is the ability to remotely control a robot, where contact (obstacle) or environment (wind gust etc) information (force feedback) is communicated from the quadrotor to the master joystick and thus giving the operator a sense of telepresence. The stability and performance of such a teleoperator is highly dependent on the amount of time delay present in the control loop. This problem is further complicated given the fact that for network based communication the time delay is itself time varying and highly non deterministic. In this paper, a novel method using Neural based Smith Predictor at the master side the stability is achieved. The performance of the system even during worst case scenario is within acceptable.

Keywords: teleoperation, quadrotor, neural smith predictor, time delay

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Authors: Chuchai Sujivorakul

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This research focused on the study of various parameters of fiber itself affecting on the flexure of hooked steel fiber reinforced concrete (HSFRC). The size of HSFRC beams was 150x150 mm in cross section and 550 mm in length, and the flexural test was carried out in accordance with EN-14651 standard. The test result was the relationship between centre-point load and crack-mount opening displacement (CMOD) at the centre notch. Controlled concrete had a compressive strength of 42 MPa. The investigated variables related to the hooked fiber itself were: (a) 3 levels of aspect ratio of fibers (65, 80 and 100); (b) 2 different fiber lengths (35 mm and 60 mm); (c) 2 different tensile strength of fibers (1100 MPa and 1500 MPa); and (d) 3 different fiber-end geometries (3D 4D and 5D fibers). The 3D hooked fibers have two plastic hinges at both ends, while the 4D and 5D hooked fibers are the newly developed steel fibers by Bekaert, and they have three and four plastic hinges at both ends, respectively. The hooked steel fibers were used in concrete with three different fiber contents, i.e., 20 30 and 40 kg/m³. From the study, it was found that all variables did not seem to affect the flexural strength at limit of proportionality (LOP) of HSFRC. However, they affected the residual flexural tensile strength (fR,j). It was observed that an increase in fiber lengths and the tensile strength the fibers would significantly increase in the fR,j of HSFRC, while the aspect ratio of the fiber would slightly effect the fR,j of HSFRC. Moreover, it was found that using 5D fibers would better enhance the fR,j and flexural behavior of HSFRC than 3D and 4D fibers, because they gave highest mechanical anchorage effect created by their hooked-end geometry.

Keywords: hooked steel fibers, fiber reinforced concrete, EN-14651, flexural test

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Authors: Amin Zabihinejad, Philippe Viarouge

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In this paper, a direct power control (DPC) strategies have been investigated in order to control a high power AC/DC converter with time variable load. This converter is composed of a three level three phase neutral point clamped (NPC) converter as rectifier and an H-bridge four quadrant current control converter. In the high power application, controller not only must adjust the desired outputs but also decrease the level of distortions which are injected to the network from the converter. Regarding this reason and nonlinearity of the power electronic converter, the conventional controllers cannot achieve appropriate responses. In this research, the precise mathematical analysis has been employed to design the appropriate controller in order to control the time variable load. A DPC controller has been proposed and simulated using Matlab/Simulink. In order to verify the simulation result, a real-time simulator- OPAL-RT- has been employed. In this paper, the dynamic response and stability of the high power NPC with variable load has been investigated and compared with conventional types using a real-time simulator. The results proved that the DPC controller is more stable and has more precise outputs in comparison with the conventional controller.

Keywords: direct power control, three level rectifier, real time simulator, high power application

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Authors: Hafiz Usama Imad, Muhammad Akram Akhund, Tauha Hussain Ali, Ali Raza Khoso, Fida Hussain Siddiqui

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Construction industry plays a significant role in fulfilling the major requirements of the human being. It is one of the major constituents of every developed country. Although the construction industry of both the developing and developed countries encompasses a major part of the economy, and millions of rupees are utilized every year on various kinds of construction projects. But, this industry is facing numerous hurdles in terms of its budget and timely completion. Construction projects generally consist of several phases like planning, designing, execution, and finishing. This research study aims to determine the significant factors of time overrun in pre-construction planning (PCP) phase of construction projects in Pakistan. Questionnaires were distributed by various means and responses of respondents were compiled and collected data were then analyzed through a statistical technique using SPSS version 24. Major causes of time overrun in pre-construction planning phase; which is an extremely important phase of construction projects, were revealed. The research conclusion will provide a pathway for stakeholders to pay attention to the mentioned causes to overcome the major issue of time overrun.

Keywords: construction industry, Pakistan, pre-construction planning phase, time overrun

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Authors: Michael Graz, Natasha Hurril, Andrew Shearer

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Research on feed supplementation with natural compounds is currently being intensively pursued with a view to improving energy utilisation in ruminants and mitigating the production of methane by these animals. Towards this end, a novel combination of extracts from garlic and bitter orange was therefore selected for trials on the basis of their previously published in vitro anti-methanogenic potential. Three separate in vitro experiments were conducted to determine energy utilisation and greenhouse gas production. These included use of rumen fluid from fistulated cows and sheep in batch culture, the Hohenheim gas test, and the Rusitec technique. Experimental and control arms were utilised, with 5g extracts per kilogram of total dietary dry matter (0.05g/kg active compounds) being used to supplement or not supplement the in vitro systems. Respiratory measurements were conducted on experimental day 1 for the batch culture and Hohenheim gas test and on day 14-21 for the Rusitec Technique (in a 21-day trial). Measurements included methane (CH4) production, total volatile fatty acid (VFA) concentration, molar proportions of acetate, propionate and butyrate and degradation of organic matter (Rusitec). CH4 production was reduced by 82% (±16%), 68% (±11%) and 37% (±4%) in the batch culture, Hohenheim gas test and Rusitec, respectively. Total VFA production was reduced by 13% (±2%) and 2% (±0.1%) in the batch culture and Hohenheim gas test whilst it was increased by 8% (±2%) in the Rusitec. Total VFA production was reduced in all tests between 2 and 10%, whilst acetate production was reduced between 10% and 29%. Propionate production which is an indicator of weight gain was increased in all cases between 16% and 30%. Butyrate production which is considered an indicator of potential milk yield was increased by between 6 and 11%. Degradation of organic matter in the Rusitec experiments was improved by 10% (±0.1%). In conclusion, the study demonstrated the potential of the combination of garlic and citrus extracts to improve digestion, enhance body energy retention and limit CH4 formation in relation to feed intake.

Keywords: citrus, garlic, methane, ruminants

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Authors: Dadang Gunawan, I. Dewa Ketut Kertawidana, Lufthi Noorfitriyani

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For the last 5 years, there is the never-ending violent act and increased cases regarding aggressive behavior among high school students in Bogor, Indonesia. Those cases caused harm to many people, even death, and lead to the continuation circle of violence. This research was conducted to evaluate the effect of using peace education and media literacy in enhancing student’s understanding about aggression, as an effort to prevent aggressive behavior. In terms of methodology, this research was done by quasi-experiment with one group pretest and post-test design. A number of 38 students who were at risk of aggressive behavior from 3 vocational high school were involved to receive a 10 learning session about peace and media literacy. The aggression questionnaire was used to identify participants, supported by student’s record in school. To collect data, the questionnaire for measuring understanding about aggression has been developed and was used after the validity and reliability of this questionnaire tested. Post-test was carried out after the session ended. Data were analyzed using t-test. The finding result showed that the mean score of student’s understanding of aggression was increased, therefore learning session of peace education and media literacy is significantly effective to enhance student’s understanding of aggression. It also showed a meaningful difference of understanding between male and female student’s whereas female students have a better understanding of aggression.

Keywords: aggressive behavior prevention, aggression, media literacy, peace education, peacebuilding

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Authors: Magdi M. E. Zumrawi, Nehla Mansour

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This paper aims to assess the efficiency of using geogrid reinforcement for subgrade stabilization. The literature of applying geogrid reinforcement technique for pavements built on soft subgrades and the previous experiences were reviewed. Laboratory tests were conducted on soil reinforced with geogrids in one or several layers. The soil specimens were compacted in four layers with or without geogrid sheets. The California Bearing Ratio (CBR) test, in soaking condition, was performed on natural soil and soil-geogrid specimens. The test results revealed that the CBR value is much affected by the geogrid sheet location and the number of sheets used in the soil specimen. When a geogrid sheet was placed at the 1^st layer of the soil, there was an increment of 26% in the CBR value. Moreover, the CBR value was significantly increased by 62% when geogrid sheets were placed at all four layers. The high CBR value is attributed to interface friction and interlock involved in the geogrid/ soil interactions. It could be concluded that geogrid reinforcement is successful and more economical technique.

Keywords: geogrid, reinforcement, stabilization, subgrade

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Authors: Wajahat Munir, Muhammad Haseeb, Adeel Anjum, Basit Raza, Ahmad Kamran Malik

Abstract:

Databases are the key components of the software systems. Due to the exponential growth of data, it is the concern that the data should be accurate and available. The data in databases is vulnerable to internal and external threats, especially when it contains sensitive data like medical or military applications. Whenever the data is changed by malicious intent, data analysis result may lead to disastrous decisions. Autonomic self-healing is molded toward computer system after inspiring from the autonomic system of human body. In order to guarantee the accuracy and availability of data, we propose a technique which on a priority basis, tries to avoid any malicious transaction from execution and in case a malicious transaction affects the system, it heals the system in an isolated mode in such a way that the availability of system would not be compromised. Using this autonomic system, the management cost and time of DBAs can be minimized. In the end, we test our model and present the findings.

Keywords: autonomic computing, self-healing, threat avoidance, security

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Authors: D. H. Park, Y. H. Tak, H. H. Kwon, G. J. Kwon, H. G. Kim

Abstract:

This study focused on developing forging technology of a large-diameter cam ring gear from the small bar. The analyses of temperature variation and deformation behavior of the material are important to obtain the optimal forging products. The hot compression test was carried out to know formability at high temperature. In order to define the optimum forging conditions including material temperature, strain and forging load, the finite element method was used to simulate the forging process of cam ring gear parts. Test results were in good agreement with the simulations. An existing cam ring gear is presented the chips generated by cutting the rod material and the durability issues, but this would be to develop a large-diameter cam ring gear forging parts for truck in order to solve the durability problem and the material waste.

Keywords: forging technology, cam ring, gear, truck, small bar

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Authors: Collins Nkapnwo Formella

Abstract:

The democratic wave of the 1980s and 1990s brought a lot of hopes to the politics of African states as many nation-states adopted ‘democracy.’ The end of the Cold War ushered in, with a lot of rush, pro-democracy movements, which led to multi-party politics, following constitutional reviews. For the very first time since independence, Africans revolted against personalized dictatorship and adopted the idea of limited office terms for the presidents. This paper dives deep into the history of Africa post-independence with the aim of allowing the readers to understand the nature of the differences in the political setups that currently govern the continent and the central region in particular. Time has proven the euphoria that characterized post-Cold War African politics at least for many countries short-lived, as their leaders were unable to re-design the institutions of governance from the compromise and interest-oriented structures handed down after independence. The result has been that politics in many of the countries have been tailored down along the lines of winner takes all approach, with the accumulation of state power being the sole objective of the leaders. The paper contends that 21ˢᵗ Century African politics is exactly the politics of inclusion/exclusion based on ethnic and interest groups, leading to the flourishing of patrimonial authoritarian regimes. It also puts to the test, whether authoritarian responses to delivering growth (economic, political, social) and peace as has been the model adopted by many leaders is superior compared to democracy. This paper then concludes by adding that the practice of democracy in the Central African region in its current form is inherently flawed from its foundations, thus incapable of rooting out the crises faced in the region.

Keywords: authoritarianism, democracy, development, power, institutions

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Authors: Alireza Monzavi Chaleshtari, Mahnaz Aliakbari Dehkordi, Amin Asadi Hieh, Majid Kazemnezhad

Abstract:

This research was conducted with the aim of determining the effectiveness of sexual cognitive behavioral therapy on psychological performance and openness to experience in women. The type of research was experimental in the form of pre-test-post-test. The statistical population of this research was made up of all working and married women with membership in the researcher's Instagram social network who had problems in marital-sexual relationships (N=900). From the statistical community, which includes working and married women who are members of the researcher's Instagram social network who have problems in marital-sexual relationships, there are 30 people including two groups (15 people in the experimental group and 15 people in the control group) as available sampling and selected randomly. They were placed in two experimental and control groups. The anxiety, stress, and depression scale (DASS) and the Costa and McCree personality questionnaire were used to collect data, and the cognitive behavioral therapy protocol of Dr. Mehrnaz Ali Akbari was used for the treatment sessions. To analyze the data, the covariance test was used in the SPSS22 software environment. The results showed that sexual cognitive behavioral therapy has a positive and significant effect on psychological performance and openness to experience in women. Conclusion: It can be concluded that interventions such as cognitive-behavioral sex can be used to treat marital problems.

Keywords: sexual cognitive behavioral therapy, psychological function, openness to experience, women

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Authors: F. S. Irwansyah, I. Farida, Y. Maulana

Abstract:

Studying chemistry requires the ability to understand three levels of understanding in the form of macroscopic, submicroscopic and symbolic, but the lack of emphasis on the submicroscopic level leads to the understanding of chemical concepts becoming incomplete, due to the limitations of the tools capable of providing visualization of submicroscopic concepts. The purpose of this study describes the stages of making augmented reality learning media on the concept of molecular geometry and analyze the feasibility test result of augmented reality learning media on the concept of molecular geometry. This research uses Research and Development (R & D) method which produces a product of AR learning media on molecular geometry concept and test the effectiveness of the product. Research stages include concept analysis and learning indicators, design development, validation, feasibility, and limited testing. The stages of validation and limited trial are aimed to get feedback in the form of assessment, suggestion and improvement on learning aspect, material substance aspect, visual communication aspect and software engineering aspects and media feasibility in terms of media creation purpose to be used in learning. The results of the overall feasibility test obtained r-calculation 0,7-0,9 with the interpretation of high feasibility value, whereas the result of limited trial got the percentage of eligibility with the average value equal to 70,83-92,5%. This percentage indicates that AR's learning media product on the concept of molecular geometry, deserves to be used as a learning resource.

Keywords: android, augmented reality, chemical learning, geometry

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Authors: B. Makhlouf, O. Bouchhida, M. Nibouche, K. Laidi

Abstract:

A variety of methods for selective harmonics elimination pulse width modulation have been developed, the most frequently used for real-time implementation based on look-up tables method. To address real-time requirements based in modified carrier signal is proposed in the presented work, with a general formulation to real-time harmonics control/elimination in switched inverters. Firstly, the proposed method has been demonstrated for a single value of the modulation index. However, in reality, this parameter is variable as a consequence of the voltage (amplitude) variability. In this context, a simple interpolation method for calculating the modified sine carrier signal is proposed. The method allows a continuous adjustment in both amplitude and frequency of the fundamental. To assess the performance of the proposed method, software simulations and hardware experiments have been carried out in the case of a single-phase inverter. Obtained results are very satisfactory.

Keywords: harmonic elimination, Particle Swarm Optimisation (PSO), polynomial interpolation, pulse width modulation, real-time harmonics control, voltage inverter

Procedia PDF Downloads 503