Search results for: allocation effect

Authors: Restituto I. Rodelas

Abstract:

The higher education has adopted the outcomes-based education from K-12. In this approach, the teacher uses any teaching and learning strategies that enable the students to achieve the learning outcomes. The students may be required to exert more effort and figure things out on their own. Hence, outcomes-based students are assumed to be more responsible and more capable of applying the knowledge learned. Another approach that the higher education in the Philippines is starting to adopt from other countries is blended learning. This combination of classroom and fully online instruction and learning is expected to be more effective. Participating in the online sessions, however, is entirely up to the students. Thus, the effect of blended learning on the performance of students in Statistics may be mediated by outcomes-based education. If there is a significant positive mediating effect, then blended learning can be optimized by integrating outcomes-based education. In this study, the sample will consist of four blended learning Statistics classes at Jose Rizal University in the second semester of AY 2015–2016. Two of these classes will be assigned randomly to the experimental group that will be handled using outcomes-based education. The two classes in the control group will be handled using the traditional lecture approach. Prior to the discussion of the first topic, a pre-test will be administered. The same test will be given as posttest after the last topic is covered. In order to establish equality of the groups’ initial knowledge, single factor ANOVA of the pretest scores will be performed. Single factor ANOVA of the posttest-pretest score differences will also be conducted to compare the performance of the experimental and control groups. When a significant difference is obtained in any of these ANOVAs, post hoc analysis will be done using Tukey's honestly significant difference test (HSD). Mediating effect will be evaluated using correlation and regression analyses. The groups’ initial knowledge are equal when the result of pretest scores ANOVA is not significant. If the result of score differences ANOVA is significant and the post hoc test indicates that the classes in the experimental group have significantly different scores from those in the control group, then outcomes-based education has a positive effect. Let blended learning be the independent variable (IV), outcomes-based education be the mediating variable (MV), and score difference be the dependent variable (DV). There is mediating effect when the following requirements are satisfied: significant correlation of IV to DV, significant correlation of IV to MV, significant relationship of MV to DV when both IV and MV are predictors in a regression model, and the absolute value of the coefficient of IV as sole predictor is larger than that when both IV and MV are predictors. With a positive mediating effect of outcomes-base education on the effect of blended learning on student performance, it will be recommended to integrate outcomes-based education into blended learning. This will yield the best learning results.

Keywords: outcome-based teaching, blended learning, face-to-face, student-centered

Procedia PDF Downloads 278

Authors: Staniek Halina

Abstract:

The inappropriate trace elements supply such as iron(III) and chromium(III) may be risk factors of many metabolic disorders (e.g., anemia, diabetes, as well cause toxic effect). However, little is known about their mutual interactions and their impact on these disturbances. The effects of Cr(III) supplementation with a deficit or excess supply of Fe(III) in vivo conditions are not known yet. The objective of the study was to investigate the combined effect of different Fe(III) levels in the diet and simultaneous Cr(III) supplementation on the Ca distribution in organs in healthy rats. The assessment was based on a two-factor (2x3) experiment carried out on 54 female Wistar rats (Rattus norvegicus). The animals were randomly divided into 9 groups and for 6 weeks, they were fed semi-purified diets AIN-93 with three different Fe(III) levels in the diet as a factor A [control (C) 45 mg/kg (100% Recommended Daily Allowance for rodents), deficient (D) 5 mg/kg (10% RDA), and oversupply (H) 180 mg/kg (400% RDA)]. The second factor (B) was the simultaneous dietary supplementation with Cr(III) at doses of 1, 50 and 500 mg/kg of the diet. Iron(III) citrate was the source of Fe(III). The complex of Cr(III) with propionic acid, also called Cr₃ or chromium(III) propionate (CrProp), was used as a source of Cr(III) in the diet. The Ca content of analysed samples (liver, kidneys, spleen, heart, and femur) was determined with the Atomic Absorption Spectrometry (AAS) method. It was found that different dietary Fe(III) supply as well as Cr(III) supplementation independently and in combination influenced Ca metabolism in healthy rats. Regardless of the supplementation of Cr(III), the oversupply of Fe(III) (180 mg/kg) decreased the Ca content in the liver and kidneys, while it increased the Ca saturation of bone tissue. High Cr(III) doses lowered the hepatic Ca content. Moreover, it tended to decrease the Ca content in the kidneys and heart, but this effect was not statistically significant. The combined effect of the experimental factors on the Ca content in the liver and the femur was observed. With the increase in the Fe(III) content in the diet, there was a decrease in the Ca level in the liver and an increase in bone saturation, and the additional Cr(III) supplementation intensified those effects. The study proved that the different Fe(III) content in the diet, independently and in combination with Cr(III) supplementation, affected the Ca distribution in organisms of healthy rats.

Keywords: calcium, chromium(III), iron(III), rats, supplementation

Procedia PDF Downloads 180

Authors: Ayman M. Othman, Hassan Y. Ahmed

Abstract:

This paper discusses the effect of using blast furnace iron slag as a part of fine aggregate on the mechanical performance of hot mix asphalt (HMA). The mechanical performance was evaluated based on various mechanical properties that include; Marshall/stiffness, indirect tensile strength and unconfined compressive strength. The effect of iron slag content on the mechanical properties of the mixtures was also investigated. Four HMA with various iron slag contents, namely; 0%, 5%, 10% and 15% by weight of total mixture were studied. Laboratory testing has revealed an enhancement in the compressive strength of HMA when iron slag was used. Within the tested range of iron slag content, a considerable increase in the compressive strength of the mixtures was observed with the increase of slag content. No significant improvement on Marshall/stiffness and indirect tensile strength of the mixtures was observed when slag was used. Even so, blast furnace iron slag can still be used in asphalt paving for environmental advantages.

Keywords: blast furnace iron slag, compressive strength, HMA, indirect tensile strength, marshall/stiffness, mechanical performance, mechanical properties

Procedia PDF Downloads 424

Authors: Madoda Cekiso, Thenjiwe Meyiwa

Abstract:

Successful postgraduate supervision involves possessing research capabilities, being knowledgeable in specific disciplines, understanding interpersonal relations, exercising mentoring/guidance skills and having appropriate knowledge of own institutional regulatory systems for postgraduate studies. On the other hand, postgraduate students are expected to know what the postgraduate journey entails and the elements and requirements of a postgraduate study. This paper sought to explore and analyse the research experiences of supervisors and postgraduate research students at one South African higher education institution. The study was qualitative in nature and a case study design was followed. The sample was purposively selected and comprised 25 postgraduate students and 20 postgraduate supervisors from one Faculty of the said university. The study findings revealed that there was no clear contract or memorandum of understanding between the postgraduate students and their supervisors. As a result, both supervisors and postgraduate students were not aware of their responsibilities. Both supervisors and postgraduate students complained about the non-availability of postgraduate facilities and resources for postgraduate students. The results further revealed that the allocation of students to supervisors who are not experts in a particular field was a challenge for both postgraduate students and supervisors. The results also revealed that the supervisors were not happy about the commitment of the postgraduate students towards their studies. The supervisors also complained about the postgraduate students who cannot work independently. Based on the findings, the authors recommended that a memorandum of understanding between a postgraduate student and a supervisor might solve some of the challenges. We further recommended a match between the supervisor’s expertise and the student’s focus area.

Keywords: feedback, mentoring, postgraduate, supervisors, student, memorandum of understanding

Procedia PDF Downloads 172

Authors: Eden G. Mariquit, Winarto Kurniawan, Masahiro Miyauchi, Hirofumi Hinode

Abstract:

This research studied the effect of adding surfactant to the titanium dioxide (TiO2) sol-gel solution that was used to immobilize TiO2 on glass substrates by dip coating technique using TiO2 sol-gel solution mixed with different types of surfactants. After dipping into the TiO2 sol, the films were calcined and produced pure anatase crystal phase. The thickness of the thin film was varied by repeating the dip and calcine cycle. The prepared films were characterized using FE-SEM, TG-DTA, and XRD, and its photocatalytic performances were tested on degradation of an organic dye, methylene blue. Aside from its phocatalytic performance, the photo-induced hydrophilicity of thin TiO2 films surface was also studied. Characterization results showed that the addition of surfactant gave rise to characteristic patterns on the surface of the TiO2 thin film which also affects the photocatalytic activity. The addition of CTAB to the TiO2 dipping solution had a negative effect because the calcination temperature was not high enough to burn all the surfactants off. As for the surface wettability, the addition of surfactant also affected the induced surface hydrophilicity of the TiO2 films when irradiated under UV light.

Keywords: photocatalysis, surface hydrophilicity, TiO2 thin films, surfactant

Procedia PDF Downloads 400

Authors: Ahmad Abu-Akel, Emilie De Montpellier, Sophie Von Bentivegni, Lyn Luechinger, Alessandro Ishii, Christine Mohr

Abstract:

Convergent and divergent thinking are two main components of creativity that have been viewed as complementary. While divergent thinking refers to the fluency and flexibility of generating new ideas, convergent thinking refers to the ability to systematically apply rules and knowledge to arrive at the optimal solution or idea. These creativity components have been shown to be susceptible to variation in subclinical expressions of autistic and schizotypal traits within the general population. Research, albeit inconclusively, mainly linked positive schizotypal traits with divergent thinking and autistic traits with convergent thinking. However, cumulative evidence suggests that these trait dimensions can co-occur in the same individual more than would be expected by chance and that their concurrent effect can be diametric and even interactive. The current study aimed at investigating the concurrent effect of these trait dimensions on tasks assessing convergent and divergent thinking abilities. We predicted that individuals with high positive schizotypal traits alone would perform particularly well on the divergent thinking task, whilst those with high autistic traits alone would perform particularly well on the convergent thinking task. Crucially, we also predicted that individuals who are high on both autistic and positive schizotypal traits would perform particularly well on both the divergent and convergent thinking tasks. This was investigated in a non-clinical sample of 142 individuals (Males = 45%; Mean age = 21.45, SD = 2.30), sufficient to minimally observe an effect size f² ≥ .10. Divergent thinking was evaluated using the Alternative Uses Task, and convergent thinking with the Anagrams Task. Autistic and schizotypal traits were respectively assessed with the Autism Quotient Questionnaire (AQ) and the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE). Regression analyses revealed that the positive association of autistic traits with convergent thinking scores was qualified with an interaction with positive schizotypal traits. Specifically, positive schizotypal traits were negatively associated with convergent thinking scores when AQ scores were relatively low, but this trend was reversed when AQ scores were high. Conversely, the positive effect of AQ scores on convergent thinking progressively increased with increasing positive schizotypal traits. The results of divergent thinking task are currently being analyzed and will be reported at the conference. The association of elevated autistic and positive schizotypal traits with convergent thinking may represent a unique profile of creative thinkers who are able to simultaneously draw on trait-specific advantages conferred by autistic and positively schizotypal traits such as local and global processing. This suggests that main-effect models can tell an incomplete story regarding the effect of autistic and positive schizotypal traits on creativity-related processes. Future creativity research should consider their interaction and the benefits conferred by their co-presence.

Keywords: autism, schizotypy, convergent thinking, divergent thinking, comorbidity

Procedia PDF Downloads 168

Authors: Desta Brhanu Gebrehiwot

Abstract:

The purpose of this review was to analyze the overall or combined effect of scholarly studies conducted on the impacts of Food for work (FFW) and Productive Safety Net Program (PSNP) on farm households’ livelihood (agricultural investment on the adoption of fertilizer, food security, livestock holding, nutrition and its’ disincentive effect) in Ethiopia. In addition, to make a critical assessment of the internal and external validity of the existing studies, the review also indicates the possibility to redesign the program. The method of selecting eligible studies for review was PICOS (Participants, Intervention, Comparison, Outcomes, and Settings) framework. The method of analysis was the fixed effects model under Meta-Analysis. The findings of this systematic review confirm the overall or combined positive significant impact of PSNP on fertilizer adoption (combined point estimate=0.015, standard error=0.005, variance=0.000, lower limit 0.004 up to the upper limit=0.026, z-value=2.726, and p-value=0.006). And the program had a significant positive impact on the child nutrition of rural households and had no significant disincentive effect. However, the program had no significant impact on livestock holdings. Thus, PSNP is important for households whose livelihood depends on rain-fed agriculture and are exposed to rainfall shocks. Thus, better to integrate the program into the national agricultural policy. In addition, most of the studies suggested that PSNP needs more attention to the design and targeting issued in order to be effective and efficient in social protection.

Keywords: meta-analysis, fixed effect model, PSNP, rural-livelihood, Ethiopia

Procedia PDF Downloads 50

Authors: Ehsan Abshirini

Abstract:

Rivers as one of the most important topographic factors have played a strategic role not only on the appearance of cities but they also affect the structure and morphology of cities. In this paper author intends to find out how a city in its physical network interacts with a river flowing inside. The pilot study is Angers, a city in western France, in which it is influenced by the Maine River. To this purpose space syntax method integrating with GIS is used to extract the properties of physical form of cities in terms of global and local integration value, accessibility and choice value. Simulating the state of absence of river in this city and comparing the result to the current state of city according to the effect of river on the morphology of areas located in different banks of river is also part of interest in this paper. The results show that although a river is not comparable to the city based on size and the area occupied by, it has a significant effect on the form of the city in both global and local properties. In addition, this study endorses that tracking the effect of river-cities and their interaction to rivers in a hybrid of space syntax and GIS may lead researchers to improve their interpretation of physical form of these types of cities.

Keywords: river-cities, Physical form, space syntax properties, GIS, topographic factor

Procedia PDF Downloads 415

Authors: Sri Harimurti, Diah Reni Asih

Abstract:

This study was designated to investigate the effect of intermittent and continuous blue lighting on the feeding behaviour, growth and corticosterone hormone concentration of broiler. Two thousands and seven hundreds unsexed day-old broiler were divided into three groups of lighting treatment. Each treatment consisted of three replicates of 300 birds. The treatments were ordinary lighting (C), intermittent blue lighting (IBL) and continuous blue lighting (CBL). The data were collected in the study were feeding behaviour such as feeding duration and frequency of feeding, growth rate of birds and corticosterone hormone concentration. Results showed that the CBL have significant effect (P<0,05) on duration and frequency of feeding and growth rate of birds. The CBL have the highest feeding duration, the lowest frequency of feeding that those 290.33±1.52 minutes/day, 35.58±0.50 times/day at 15 to 28 days of age.The concentration of corticosterone hormone of IBL and CBL were a significant (P<0.05) decrease. The conclusion of this study indicated that continuous blue lighting may be a good tool for improving welfare management of broiler.

Keywords: blue light, broiler chickens, corticosterone hormone, feeding behaviour, growth rate

Procedia PDF Downloads 322

Authors: Nosheen Fatima Warraich

Abstract:

One of the most often used models in information system (IS) research is the technology acceptance model (TAM). This meta-analysis aims to measure the relationship between TAM variables, Perceived Ease of Use (PEOU), and Perceived Usefulness (PU) with users’ attitudes and behavioral intention (BI) in mobile and digital libraries context. It also examines the relationship of external variables (information quality and system quality) with TAM variables (PEOU and PU) in digital libraries settings. This meta-analysis was performed through PRISMA-P guidelines. Four databases (Google Scholar, Web of Science, Scopus, and LISTA) were utilized for searching, and the search was conducted according to defined criteria. The findings of this study revealed a large effect size of PU and PEOU with BI. There was also a large effect size of PU and PEOU with attitude. A medium effect size was found between SysQ -> PU, InfoQ-> PU, and SysQ -> PEOU. However, there was a small effect size between InfoQ and PEOU. It fills the literature gap and also confirms that TAM is a valid model for the acceptance and use of technology in mobile and digital libraries context. Thus, its findings would be helpful for developers and designers in designing and developing mobile library apps. It will also be beneficial for library authorities and system librarians in designing and developing digital libraries in academic settings.

Keywords: technology acceptance model (tam), perceived ease of use, perceived usefulness, information quality, system quality, meta-analysis, systematic review, digital libraries, and mobile library apps.

Procedia PDF Downloads 54

Authors: Hend Almaseb

Abstract:

Child aggression is a serious social problem that affects children’s lives. This study examines the relationship between three types of aggressive behaviors–physical, verbal, and indirect aggression–from sociocultural and social work perspectives. Also, it investigates the effect of gender on the three types of aggressive behaviors and the most frequently used aggressive behaviors among a sample of 329 Kuwaiti children. The results show that there is a positive correlation between the three types of aggression and gender.

Keywords: child aggression, indirect aggression, physical aggression, verbal aggression

Procedia PDF Downloads 358

Authors: Michele Sinico

Abstract:

The present research investigates the effect of symmetry on the perception of happiness and boredom in design products. Three experiments were carried out in order to verify the degree of the visual expressive value on different models of bookcases, wall clocks, and chairs. 60 participants directly indicated the degree of happiness and boredom using 7-point rating scales. The findings show that the participants acknowledged a different value of expressive quality in the different product models. Results show also that symmetry is not a significant constraint for an emotional design project.

Keywords: product experience, emotional design, symmetry, expressive qualities

Procedia PDF Downloads 135

Authors: A. Chellil, A. Nour, S. Lecheb, H. Mechakra, A. Bouderba, H. Kebir

Abstract:

In this paper, the dynamic response for the instability of a composite rotor is presented, under dynamic loading response in the harmonic analysis condition. The analysis of the stress which operates the rotor is done. Calculations of different energies and the virtual work of the aerodynamic loads from the rotor blade is developed. The use of the composite material for the rotor, offers a good stability. Numerical calculations on the model develop of three dimensions prove that the damage effect has a negative effect on the stability of the rotor. The study of the composite rotor in transient system allowed to determine the vibratory responses due to various excitations.

Keywords: rotor, composite, damage, finite element, numerical

Procedia PDF Downloads 515

Authors: G. Lei, P. C. Dong, X. Q. Cen, S. Y. Mo

Abstract:

One of the most significant parameters, describing the effect of water flooding in porous media, is flood-response time, and it is an important index in oilfield development. The responding time in low permeability reservoir is usually calculated by the method of stable state successive substitution neglecting the effect of medium deformation. Numerous studies show that the media deformation has an important impact on the development for low permeability reservoirs and can not be neglected. On the base of streamline tube model, we developed a method to interpret responding time with medium deformation factor. The results show that: the media deformation factor, threshold pressure gradient and well spacing have a significant effect on the flood response time. The greater the media deformation factor, threshold pressure gradient or well spacing is, the lower the flood response time is. The responding time of different streamlines varies. As the angle with the main streamline increases, the water flooding response time delays as a "parabola" shape.

Keywords: low permeability, flood-response time, threshold pressure gradient, medium deformation

Procedia PDF Downloads 483

Authors: U. P. Rathnakar, Sejpal Jaykumar, Shenoy K. Ashok

Abstract:

The effect of Shilajit was investigated for lipid lowering activity and its effect on weight gain in Wistar albino rats. Shilajit, semi-hard brownish black resin formed through long-term humidification of several plant types, mainly bryophytes, can be obtained from steep rocks of the Himalayas at altitudes between 1000 to 5000 meters. Hyperlipidemia was produced by feeding the rats with the cholesterol-rich high-fat diet (HFD) for 2 months. This diet contained deoxycholic acid, cholesterol and warm coconut oil in powdered rat chow diet. At the end of study, Shilajit treated rats showed significant decrease in serum LDL, triglyceride and total cholesterol level as well as increase in serum HDL level, in comparison to rats fed on high-fat diet with no treatment. Also during study period, increase in weight in Shilajit treated group was significantly less than in the other group of rats fed on high-fat diet with no treatment. Thus, Shilajit has significantly controlled the development of hyperlipidemia and weight gain in high-fat diet fed rats in the present study.

Keywords: Shilajit, hyperlipidemia, weight control, cholesterol-rich high-fat diet

Procedia PDF Downloads 173

Authors: Zair Firdaous, Fourka Mohamed, Elfelsoufi Zoubir

Abstract:

The arrival of e-commerce has changed the supply chain management on the operational level as well as on the organization and strategic and even tactical decisions of the companies. The optimization of resources is an issue that is needed on the tactical and operational strategic plan. This work considers the allocation of resources in the case of pure players that have launched online sales. The aim is to improve the level of customer satisfaction and maintaining the benefits of e-retailer and of its cooperators and reducing costs and risks. We first modeled the B2C chain with all operations that integrates and possible scenarios since online retailers offer a wide selection of personalized service. The personalized services that online shopping companies offer to the clients can be embodied in many aspects, such as the customizations of payment, the distribution methods, and after-sales service choices. Every aspect of customized service has several modes. At that time, we analyzed the optimization problems of supply chain resource in customized online shopping service mode. Then, we realized an optimization model and algorithm for the development based on the analysis of the of the B2C supply chain resources. It is a multi-objective optimization that considers the collaboration of resources in operations, time and costs but also the risks and the quality of services as well as dynamic and uncertain characters related to the request.

Keywords: supply chain resource, e-commerce, pure-players, optimization

Procedia PDF Downloads 237

Authors: S. Neelima, P. S. Subramanyam

Abstract:

A distribution system is an interface between the bulk power system and the consumers. Among these systems, radial distributions system is popular because of low cost and simple design. In distribution systems, the voltages at buses reduces when moved away from the substation, also the losses are high. The reason for a decrease in voltage and high losses is the insufficient amount of reactive power, which can be provided by the shunt capacitors. But the placement of the capacitor with an appropriate size is always a challenge. Thus, the optimal capacitor placement problem is to determine the location and size of capacitors to be placed in distribution networks in an efficient way to reduce the power losses and improve the voltage profile of the system. For this purpose, in this paper, two stage methodologies are used. In the first stage, the load flow of pre-compensated distribution system is carried out using ‘dimension reducing distribution load flow algorithm (DRDLFA)’. On the basis of this load flow the potential locations of compensation are computed. In the second stage, Genetic Algorithm (GA) technique is used to determine the optimal location and size of the capacitors such that the cost of the energy loss and capacitor cost to be a minimum. The above method is tested on IEEE 9 and 34 bus system and compared with other methods in the literature.

Keywords: dimension reducing distribution load flow algorithm, DRDLFA, genetic algorithm, electrical distribution network, optimal capacitors placement, voltage profile improvement, loss reduction

Procedia PDF Downloads 373

Authors: Sabrina Sebbane, Alina Elena Parvu

Abstract:

Introduction: Santolina rosmarinifolia is a plant of the Santolina genus, a family made of medicinal plants widely used. Some of the Santolina species have been proven to have potent anti-inflammatory and anti-oxidant effects. However, no in vivo study has been made to demonstrate this in Santolina rosmarinifolia. The aim of our study is to experimentally evaluate the potential anti-inflammatory and anti-oxidant effects of Santolina rosmarinifolia plant extracts on acute inflammation in rats. These effects are defined by measuring the modifications on nitric oxide, reactive oxygen species and anti-oxidant response in serum. Materials and Methods: Rats were divided into 5 groups (n=6). Three groups were given Santolina rosmarinifolia extract by gavage in different concentrations(100%, 50%, 25%) for a week. Inflammation was induced by i.m injection of turpentine oil on the 8th day. One group was only given turpentine oil and the fifth group acted as control and was given only saline solution. Blood was collected and serum separated. Global tests were used to measure the oxidative stress, total oxidative status (TOS), total antioxidant reactivity (TAR) and the modified method of Griess assay to measure NO synthesis. Malondilaldehyde (MDA) and thiols levels were also assessed. Results: Santolina rosmarinifolia did not significantly change the TOS levels (p > 0.05). Santolina rosmarinifolia 25% and 50% decreased significantly the TAR levels (p < 0.001). Santolina 100% didn't have a significant effect on TAR (p > 0.05). All concentrations of Santolina rosmarinifolia increased the oxidative stress index (OSI) significantly(p < 0.05). Santolina rosmarinifolia 100% significantly decreased NO synthesis (p value < 0.05). In the diluted Santolina groups, no significant effect on NO synthesis was observed. In the groups treated with Santolina 100% and Santolina rosmarinifolia 50%, thiols concentration were significantly higher compared to the inflammation group (p < 0.02). A higher stimulatory effect was found in the Santolina 25% group (p value < 0.05). MDA levels were not significantly modified by the administration of Santolina rosmarinifolia (p > 0.05). Conclusion: All three solutions of Santolina rosmarinifolia had no important effect on oxidant production. However, Santolina rosmarinifolia solutions had a positive effect by increasing the thiols concentration in the serum of the models. The sum of all the effects produced by the administration of Santolina did not show a significant decrease of nitro-oxidative stress. Further experiments including smaller concentrations of Santolina rosmarinifolia will be made. Santolina rosmarinifolia should also be tested as a curative treatment.

Keywords: inflammation, MDA, nitric oxide, santolina rosmarinifolia, thiols, TAR, TOS

Procedia PDF Downloads 247

Authors: Benalia Kouini, Aicha Serier

Abstract:

Nanocomposites based on polypropylene/polyamide 66 (PP/PA66) nanoblends containing organophilic montmorillonite (OMMT) and maleic anhydride grafted polypropylene (PP-g-MAH) were prepared by melt compounding method followed by injection molding. Two different types of nanoclays were used in this work. DELLITE LVF is the untreated nanoclay and DELLITE 67G is the treated one. The morphology of the nanocomposites was studied using the XR diffraction (XRD). The results indicate that the incorporation of treated nanoclay has a significant effect on the impact strength of PP/PA66 nanocomposites. Furthermore, it was found that XRD results revealed the intercalation, exfoliation of nanaclays of nanocomposites.

Keywords: nNanoclay, Nanocomposites, Polypropylene, Polyamide, melt processing, mechanical properties.

Procedia PDF Downloads 335

Authors: Smita Jauhari, Bhupendra Mistry

Abstract:

Schiff base (E)-2-methyl-N-(tetrazolo[1,5-a]quinolin-4-ylmethylene)aniline (QMA) was synthesized, and its inhibitive effect for mild steel in 1M HCl solution was investigated by weight loss measurement and electrochemical tests.From the weight loss measurements and electrochemical tests, it was observed that the inhibition efficiency increases with the increase in the Schiff base concentration and reaches a maximum at the optimum concentration. This is further confirmed by the decrease in corrosion rate. It is found that the system follows Langmuir adsorption isotherm.

Keywords: Schiff base, acid corrosion, electrochemical impedance spectroscopy, polarization

Procedia PDF Downloads 347

Authors: Hamid Hamli Benzahar

Abstract:

The main goal of this research is to study the deflection of a composite beam CB taking into account the effect of shear deformation. The structure is made up of two beams of different sections, joined together by thin adhesive, subjected to end moments and a distributed load. The fundamental differential equation of CB can be obtained from the total energy equation while considering the shear deformation. The differential equation found will be compared with those found in CB, where the shear deformation is zero. The CB system is numerically modeled by the finite element method, where the numerical results of deflection will be compared with those found theoretically.

Keywords: composite beam, shear deformation, moments, finites elements

Procedia PDF Downloads 54

Authors: Anurag Sharma, Rahul Malhotra, Love Kumar, Harjit Pal Singh

Abstract:

This paper demonstrates OCDM-ROF based hybrid architecture where data/voice communication is enabled via a permutation of Optical Code Division Multiplexing (OCDM) and Radio-over-Fiber (RoF) techniques under various diverse conditions. OCDM-RoF hybrid network of 16 users with DPSK modulation format has been designed and performance of proposed network is analyzed for 100, 150, and 200 km fiber span length under the influence of linear and nonlinear effect. It has been reported that Polarization Mode Dispersion (PMD) has the least effect while other nonlinearity affects the performance of proposed network.

Keywords: OCDM, RoF, DPSK, PMD, eye diagram, BER, Q factor

Procedia PDF Downloads 620

Authors: Erkan Koç, Mehmet Ünal, Ercan Candan

Abstract:

In this study, the effect of zinc content (0.5-3.0 wt.%) in as-cast Mg-3Al alloy which were fabricated with high-purity raw materials towards the microstructure and mechanical properties was studied. Microstructure results showed that increase in zinc content changed the secondary phase distribution of the alloys. Mechanical test results demonstrate that with the increasing Zn addition the enhancement of the hardness value by 29%, ultimate tensile strength by 16% and yield strength by 15% can be achieved as well as decreasing of elongation by 33%. The improvement in mechanical properties for Mg-Al–Zn alloys with increasing Zn content up to 3% of weight may be ascribed to second phase strengthening.

Keywords: magnesium, zinc, mechanical properties, Mg17Al12

Procedia PDF Downloads 403

Authors: B. Fazekas, I. Korolov, K. Kutasi

Abstract:

Plasma medicine, which involves the use of gas discharge plasmas for medical applications is a rapidly growing research field. The use of non-thermal atmospheric pressure plasmas in dermatology to assist tissue regeneration by improving the healing of infected and/or chronic wounds is a promising application. It is believed that plasma can activate cells, which are involved in the wound closure. Non-thermal atmospheric plasmas are rich in chemically active species (such as O and N-atoms, O2(a) molecules) and radiative species such as the NO, N2+ and N2 excited molecules, which dominantly radiate in the 200-500 nm spectral range. In order to understand the effect of plasma species, both of chemically active and radiative species on wound healing process, the interaction of physical plasma with the human skin cells is necessary. In order to clarify the effect of plasma radiation on the wound healing process we treated keratinocyte cells – that are one of the main cell types in human skin epidermis – covered with a layer of phosphate-buffered saline (PBS) with a low power atmospheric pressure plasma. For the generation of such plasma we have applied a plasma needle. Here, the plasma is ignited at the tip of the needle in flowing helium gas in contact with the ambient air. To study the effect of plasma radiation we used a plasma needle configuration, where the plasma species – chemically active radicals and charged species – could not reach the treated cells, but only the radiation. For the comparison purposes, we also irradiated the cells using a UV-B light source (FS20 lamp) with a 20 and 40 mJ cm-2 dose of 312 nm. After treatment the viability and the proliferation of the cells have been examined. The proliferation of cells has been studied with a real time monitoring system called Xcelligence. The results have indicated, that the 20 mJ cm-2 dose did not affect cell viability, whereas the 40 mJ cm-2 dose resulted a decrease in cell viability. The results have shown that the plasma radiation have no quantifiable effect on the cell proliferation as compared to the non-treated cells.

Keywords: UV radiation, non-equilibrium gas discharges (non-thermal plasmas), plasma emission, keratinocyte cells

Procedia PDF Downloads 589

Authors: Hani Baek, Gwang Min Sun, Chansun Shin, Sung Ho Ahn

Abstract:

Fast neutron irradiation using nuclear reactors is an effective method to improve switching loss and short circuit durability of power semiconductor (insulated gate bipolar transistors (IGBT) and insulated gate transistors (IGT), etc.). However, not only fast neutrons but also thermal neutrons, epithermal neutrons and gamma exist in the nuclear reactor. And the electrical properties of the IGBT may be deteriorated by the irradiation of gamma. Gamma irradiation damages are known to be caused by Total Ionizing Dose (TID) effect and Single Event Effect (SEE), Displacement Damage. Especially, the TID effect deteriorated the electrical properties such as leakage current and threshold voltage of a power semiconductor. This work can confirm the effect of the gamma irradiation on the electrical properties of 600 V NPT-IGBT. Irradiation of gamma forms lattice defects in the gate oxide and Si-SiO₂ interface of the IGBT. It was confirmed that this lattice defect acts on the center of the trap and affects the threshold voltage, thereby negatively shifted the threshold voltage according to TID. In addition to the change in the carrier mobility, the conductivity modulation decreases in the n-drift region, indicating a negative influence that the forward voltage drop decreases. The turn-off delay time of the device before irradiation was 212 ns. Those of 2.5, 10, 30, 70 and 100 kRad(Si) were 225, 258, 311, 328, and 350 ns, respectively. The gamma irradiation increased the turn-off delay time of the IGBT by approximately 65%, and the switching characteristics deteriorated.

Keywords: NPT-IGBT, gamma irradiation, switching, turn-off delay time, recombination, trap center

Procedia PDF Downloads 142

Authors: M. C. Yu, Z. L. Niu, L. G. Zhang, W. W. Cui, Y. L. Zhang

Abstract:

According to the theory of the vibration isolation for linear systems, linear damping can reduce the transmissibility at the resonant frequency, but inescapably increase the transmissibility of the isolation frequency region. To resolve this problem, nonlinear vibration isolation technology has recently received increasing attentions. Shear thickening fluid (STF) is a special colloidal material. When STF is subject to high shear rate, it rheological property changes from a flowable behavior into a rigid behavior, i.e., it presents shear thickening effect. STF isolator is a vibration isolator using STF as working material. Because of shear thickening effect, STF isolator is a variable-damped isolator. It exhibits small damping under high vibration frequency and strong damping at resonance frequency due to shearing rate increasing. So its special inherent character is very favorable for vibration isolation, especially for restraining resonance. In this paper, firstly, STF was prepared by dispersing nano-particles of silica into polyethylene glycol 200 fluid, followed by rheological properties test. After that, an STF isolator was designed. The vibration isolation system supported by STF isolator was modeled, and the numerical simulation was conducted to study the vibration isolation properties of STF. And finally, the effect factors on vibrations isolation performance was also researched quantitatively. The research suggests that owing to its variable damping, STF vibration isolator can effetely restrain resonance without bringing unfavorable effect at high frequency, which meets the need of ideal damping properties and resolves the problem of traditional isolators.

Keywords: shear thickening fluid, variable-damped isolator, vibration isolation, restrain resonance

Procedia PDF Downloads 163

Authors: Ch. Sridevi, S. P. Shailender Kumar, B. Gurudayal, A. Chalapathi Rao, K. Koteswara Rao, P. Srinivasulu

Abstract:

System reliability and system availability evaluation plays a crucial role in ensuring the seamless operation of complex satellite data reception system with consistent performance for longer periods. This paper presents a novel approach for the same using a case study on one of the antenna systems at satellite data reception ground station in India. The methodology involves analyzing system's components, their failure rates, system's architecture, generation of logical reliability block diagram model and estimating the reliability of the system using the component level mean time between failures considering exponential distribution to derive a baseline estimate of the system's reliability. The model is then validated with collected system level field failure data from the operational satellite data reception systems that includes failure occurred, failure time, criticality of the failure and repair times by using statistical techniques like median rank, regression and Weibull analysis to extract meaningful insights regarding failure patterns and practical reliability of the system and to assess the accuracy of the developed reliability model. The study mainly focused on identification of critical units within the system, which are prone to failures and have a significant impact on overall performance and brought out a reliability model of the identified critical unit. This model takes into account the interdependencies among system components and their impact on overall system reliability and provides valuable insights into the performance of the system to understand the Improvement or degradation of the system over a period of time and will be the vital input to arrive at the optimized design for future development. It also provides a plug and play framework to understand the effect on performance of the system in case of any up gradations or new designs of the unit. It helps in effective planning and formulating contingency plans to address potential system failures, ensuring the continuity of operations. Furthermore, to instill confidence in system users, the duration for which the system can operate continuously with the desired level of 3 sigma reliability was estimated that turned out to be a vital input to maintenance plan. System availability and station availability was also assessed by considering scenarios of clash and non-clash to determine the overall system performance and potential bottlenecks. Overall, this paper establishes a comprehensive methodology for reliability and availability analysis of complex satellite data reception systems. The results derived from this approach facilitate effective planning contingency measures, and provide users with confidence in system performance and enables decision-makers to make informed choices about system maintenance, upgrades and replacements. It also aids in identifying critical units and assessing system availability in various scenarios and helps in minimizing downtime and optimizing resource allocation.

Keywords: exponential distribution, reliability modeling, reliability block diagram, satellite data reception system, system availability, weibull analysis

Procedia PDF Downloads 69

Authors: P. Gayathri, G. P. Jeyanthi

Abstract:

The bark of Polyalthia longifolia is used in ayurvedic system of medicine for the manangement of various ailments including diabetes mellitus. The bark of P. longifolia extracts was extracted using various polar and non-polar solvents and tested for inhibition of alpha-amylase and alpha-glucosidase among which the ethanolic extracts were found to be more potent. The ethanolic extracts of the bark were tested for the in vitro inhibition of alpha-amylase using starch as substrate and alpha-glucosidase using p-nitro phenyl alpha-D-gluco pyranoside as substrate to establish its in vitro antidiabetic effect. The mechanism of inhibition was determined by Dixon plot and Cornish-Bowden plot. The cytotoxic effect of the extract was tested on L6 and Vero cell-lines. The extract was partially purified by TLC. The individual effect of the ethanolic extract, TLC fractions and its combinatorial effect with insulin and glibenclamide on glucose uptake by rat hemi-diaphragm were studied.Results revealed that the ethanolic extracts of Polyalthia longifolia bark exhibited competitive inhibition of alpha-amylase and alpha-glucosidase. The extracts were also found not to be cytotoxic at the highest dose of 1 mg/mL. Glucose uptake study revealed that the extract alone and when combined with insulin, decreased the glucose uptake when compared to insulin control, however the purified TLC fractions exhibited significantly higher (p<0.05) glucose uptake by the rat hemi-diaphragm when compared to insulin. The study shows various possible mechanism of in vitro antidiabetic effect of the P. longifolia bark.

Keywords: alpha-amylase, alpha-glucosidase, dixon, cornish-bowden, L6 , Vero cell-lines, glucose uptake, polyalthia longifolia bark, ethanolic extract, TLC fractions

Procedia PDF Downloads 458

Authors: Jehad Al Dallal

Abstract:

Class cohesion is a key object-oriented software quality attribute that is used to evaluate the degree of relatedness of class attributes and methods. Researchers have proposed several class cohesion measures. However, the effect of considering the special methods (i.e., constructors, destructors, and access and delegation methods) in cohesion calculation is not thoroughly theoretically studied for most of them. In this paper, we address this issue for three popular connectivity-based class cohesion measures. For each of the considered measures we theoretically study the impact of including or excluding special methods on the values that are obtained by applying the measure. This study is based on analyzing the definitions and formulas that are proposed for the measures. The results show that including/excluding special methods has a considerable effect on the obtained cohesion values and that this effect varies from one measure to another. For each of the three connectivity-based measures, the proposed theoretical study recommended excluding the special methods in cohesion measurement.

Keywords: object-oriented class, software quality, class cohesion measure, class cohesion, special methods

Procedia PDF Downloads 279

Authors: Hamid Ghasemzadeh- Nava, Maziar Kaveh Baghbadorani, Amin Tamadon

Abstract:

Considering response of uterus to ecbolic effect of oxytocin near the time of parturition, this study was done for investigating the effect of prophylactic administration of this hormone on duration of fetal membrane retention, time interval to first detectable estrus, time interval to first service, and conception rate at first service in cases of both normal parturition and dystocia. For this reason cows with (n=18) and without (n=18) dystocia assigned randomly to treatment (n=12) or control (n=6) groups and received intramuscular injection of 100 IU of oxytocin or 10 mL of normal saline respectively. Further observations and investigations indicate that duration of fetal retention is significantly shorter in treatment group cows compared to control groups, regardless of having dystocia (P=0.002) or normal spontaneous calving (P=0.001). The same trend exists for conception rate at first service in which cows in treatment groups had significantly higher conception rate (CR) in comparison to cows in control groups with (P=0.0003) or without dystocia (P=0.017). The time interval to first detected heat and first service didn’t show any difference between groups.

Keywords: conception rate, oxytocin, RFM, time to first service

Procedia PDF Downloads 423