Search results for: sieving particle size

Authors: Antar Bouhank, Youcef Beellal, Samir Adjel, Abdelmadjid Ababsa

Abstract:

This paper investigates the impact of 3D printing parameters using the cold metal transfer (CMT) technique on the morphological, mechanical, and tribological properties of walls and massive parts made from aluminum alloy. The parameters studied include current intensity, torch movement speed, printing increment, and the flow rate of shielding gas. The manufactured parts, using the technique mentioned above, are walls and massive parts with different filling strategies, using grid and zigzag patterns and at different current intensities. The main goal of the article is to find out the welding parameters suitable for having parts with low defects and improved properties from the previously mentioned properties point of view. It has been observed from the results thus obtained that the high current intensity causes rapid solidification, resulting in high porosity and low hardness values. However, the high current intensity can cause very rapid solidification, which increases the melting point, and the part remains in the most stable shape. Furthermore, the results show that there is an evident relationship between hardness, coefficient of friction and wear test where the high intensity is, the low hardness is. The same note is for the coefficient of friction. The micrography of the walls shows a random granular structure with fine grain boundaries with a different grain size. Some interesting results are presented in this paper.

Keywords: aluminum alloy, porosity, microstructures, hardness

Procedia PDF Downloads 46

Authors: Funke Morenike Jiyah, Joshua Jiyah

Abstract:

The occurrence of various health issues have been linked to excessive noise pollution in all works of life as evident in many research efforts. This study provides empirical analysis of the effects of noise pollution on the well-being of the residents of Bida Local Government Area, Niger State, Nigeria. The study adopted a case study research design, involving cross-sectional procedure. Field observations and medical reports were obtained to support the respondents’ perception on the state of their well-being. The sample size for the study was selected using the housing stock in the various wards. One major street in each ward was selected. A total of 1,833 buildings were counted along the sampled streets and 10% of this was selected for the administration of structured questionnaire.The environmental quality of the wards was determined by measuring the noise level using Testo 815 noise meters. The result revealed that Bariki ward which houses the GRA has the lowest noise level of 37.8 dB(A)while the noise pollution levels recorded in the other thirteen wards were all above the recommended levels. The average ambient noise level in sawmills, commercial centres, road junctions and industrial areas were above 90 dB(A). The temporal record from the Federal Medical Centre, Bida revealed that, apart from malaria, hypertension (5,614 outpatients) was the most prevalent health issue in 2013 alone. The paper emphasised the need for compatibility consideration in the choice of residential location, the use of ear muffler and effective enforcement of zoning regulations.

Keywords: bida, decibels, environmental quality, noise, well-being

Procedia PDF Downloads 133

Authors: Amjad Almunyif, Amra Alhassni, Sultan Alhassan, Maryam Al Huwayz, Saud Alotaibi, Abdulaziz Almalki, Mohamed Henini

Abstract:

The effect of rapid thermal annealing (RTA) on the optical properties of InAs quantum dots (QDs) grown at an As overpressure of 2x 10⁻⁶ Torr by molecular beam epitaxy (MBE) on (100) and (311)B GaAs substrates was investigated using photoluminescence (PL) technique. PL results showed that for the as-grown samples, the QDs grown on the high index plane (311)B have lower PL intensity and lower full width at half maximum (FWHM) than those grown on the conventional (100) plane. The latter demonstrates that the (311)B QDs have better size uniformity than (100) QDs. Compared with as-grown samples, a blue-shift was observed for all samples with increasing annealing temperature from 600°C to 700°C. For (100) samples, a narrowing of the FWHM was observed with increasing annealing temperature from 600°C to 700°C. However, in (311)B samples, the FWHM showed a different behaviour; it slightly increased when the samples were annealed at 600°C and then decreased when the annealing temperature increased to 700°C. As expected, the PL peak intensity for all samples increased when the laser excitation power increased. The PL peak energy temperature dependence showed a strong redshift when the temperature was increased from 10 K to 120 K. The PL peak energy exhibited an abnormal S-shape behaviour as a function of temperature for all samples. Most samples exhibited a significant enhancement in their activation energies when annealed at 600°C and 700°C, suggesting that annealing annihilated defects created during sample growth.

Keywords: RTA, QDs, InAs, MBE

Procedia PDF Downloads 176

Authors: N. K. Chougule, G. V. Parishwad

Abstract:

The pin fin heat sink is a novel heat transfer device to transfer large amount of heat through with very small temperature differences and it also possesses large uniform cooling characteristics. Pin fins are widely used as elements that provide increased cooling for electronic devices. Increasing demands regarding the performance of such devices can be observed due to the increasing heat production density of electronic components. For this reason, extensive work is being carried out to select and optimize pin fin elements for increased heat transfer. In this paper, the effects of design parameters and the optimum design parameters for a Pin-Fin heat sink (PFHS) under multi-jet impingement case with thermal performance characteristics have been investigated by using Taguchi methodology based on the L9 orthogonal arrays. Various design parameters, such as pin-fin array size, gap between nozzle exit to impingement target surface (Z/d) and air velocity are explored by numerical experiment. The average convective heat transfer coefficient is considered as the thermal performance characteristics. The analysis of variance (ANOVA) is applied to find the effect of each design parameter on the thermal performance characteristics. Then the results of confirmation test with the optimal level constitution of design parameters have obviously shown that this logic approach can effective in optimizing the PFHS with the thermal performance characteristics. The analysis of the Taguchi method reveals that, all the parameters mentioned above have equal contributions in the performance of heat sink efficiency. Experimental results are provided to validate the suitability of the proposed approach.

Keywords: Pin Fin Heat Sink (PFHS), Taguchi method, CFD, thermal performance

Procedia PDF Downloads 248

Authors: RAM PAL SINGH, VIKASH CHAUDHARY, MONIKA VERMA

Abstract:

In this paper, we proposed the implementation of optimization based Extreme Learning Machine (ELM) for watermarking of B-channel of color image in discrete wavelet transform (DWT) domain. ELM, a regularization algorithm, works based on generalized single-hidden-layer feed-forward neural networks (SLFNs). However, hidden layer parameters, generally called feature mapping in context of ELM need not to be tuned every time. This paper shows the embedding and extraction processes of watermark with the help of ELM and results are compared with already used machine learning models for watermarking.Here, a cover image is divide into suitable numbers of non-overlapping blocks of required size and DWT is applied to each block to be transformed in low frequency sub-band domain. Basically, ELM gives a unified leaning platform with a feature mapping, that is, mapping between hidden layer and output layer of SLFNs, is tried for watermark embedding and extraction purpose in a cover image. Although ELM has widespread application right from binary classification, multiclass classification to regression and function estimation etc. Unlike SVM based algorithm which achieve suboptimal solution with high computational complexity, ELM can provide better generalization performance results with very small complexity. Efficacy of optimization method based ELM algorithm is measured by using quantitative and qualitative parameters on a watermarked image even though image is subjected to different types of geometrical and conventional attacks.

Keywords: BER, DWT, extreme leaning machine (ELM), PSNR

Procedia PDF Downloads 311

Authors: Shin Woo Kim, Eui Ju Lee

Abstract:

The recent development of biofuel production technology facilitates the use of bioethanol and biodiesel on automobile. Bioethanol, especially, can be used as a fuel for gasoline vehicles because the addition of ethanol has been known to increase octane number and reduce soot emissions. However, the wide application of biofuel has been still limited because of lack of detailed combustion properties such as auto-ignition temperature and pollutant emissions such as NOx and soot, which has been concerned mainly on the vehicle fire safety and environmental safety. In this study, the combustion characteristics of gasoline/ethanol fuel were investigated both numerically and experimentally. For auto-ignition temperature and NOx emission, the numerical simulation was performed on the well-stirred reactor (WSR) to simulate the homogeneous gasoline engine and to clarify the effect of ethanol addition in the gasoline fuel. Also, the response surface method (RSM) was introduced as a design of experiment (DOE), which enables the various combustion properties to be predicted and optimized systematically with respect to three independent variables, i.e., ethanol mole fraction, equivalence ratio and residence time. The results of stoichiometric gasoline surrogate show that the auto-ignition temperature increases but NOx yields decrease with increasing ethanol mole fraction. This implies that the bioethanol added gasoline is an eco-friendly fuel on engine running condition. However, unburned hydrocarbon is increased dramatically with increasing ethanol content, which results from the incomplete combustion and hence needs to adjust combustion itself rather than an after-treatment system. RSM results analyzed with three independent variables predict the auto-ignition temperature accurately. However, NOx emission had a big difference between the calculated values and the predicted values using conventional RSM because NOx emission varies very steeply and hence the obtained second order polynomial cannot follow the rates. To relax the increasing rate of dependent variable, NOx emission is taken as common logarithms and worked again with RSM. NOx emission predicted through logarithm transformation is in a fairly good agreement with the experimental results. For more tangible understanding of gasoline/ethanol fuel on pollutant emissions, experimental measurements of combustion products were performed in gasoline/ethanol pool fires, which is widely used as a fire source of laboratory scale experiments. Three measurement methods were introduced to clarify the pollutant emissions, i.e., various gas concentrations including NOx, gravimetric soot filter sampling for elements analysis and pyrolysis, thermophoretic soot sampling with transmission electron microscopy (TEM). Soot yield by gravimetric sampling was decreased dramatically as ethanol was added, but NOx emission was almost comparable regardless of ethanol mole fraction. The morphology of the soot particle was investigated to address the degree of soot maturing. The incipient soot such as a liquid like PAHs was observed clearly on the soot of higher ethanol containing gasoline, and the soot might be matured under the undiluted gasoline fuel.

Keywords: gasoline/ethanol fuel, NOx, pool fire, soot, well-stirred reactor (WSR)

Procedia PDF Downloads 212

Authors: Ali Almadan, Anoop Krishnan, Ajita Rattani

Abstract:

Facial recognition is a widely adopted technology in surveillance, border control, healthcare, banking services, and lately, in mobile user authentication with Apple introducing “Face ID” moniker with iPhone X. A lot of research has been conducted in the area of face recognition on datasets captured by surveillance cameras, DSLR, and mobile devices. Recently, face recognition technology has also been deployed on body-worn cameras to keep officers safe, enabling situational awareness and providing evidence for trial. However, limited academic research has been conducted on this topic so far, without the availability of any publicly available datasets with a sufficient sample size. This paper aims to advance research in the area of face recognition using body-worn cameras. To this aim, the contribution of this work is two-fold: (1) collection of a dataset consisting of a total of 136,939 facial images of 102 subjects captured using body-worn cameras in in-door and daylight conditions and (2) evaluation of various deep-learning architectures for face identification on the collected dataset. Experimental results suggest a maximum True Positive Rate(TPR) of 99.86% at False Positive Rate(FPR) of 0.000 obtained by SphereFace based deep learning architecture in daylight condition. The collected dataset and the baseline algorithms will promote further research and development. A downloadable link of the dataset and the algorithms is available by contacting the authors.

Keywords: face recognition, body-worn cameras, deep learning, person identification

Procedia PDF Downloads 163

Authors: Hugo Lefeuvre, Jerôme Donnard, Michael Descostes, Sophie Billon, Samuel Duval, Tugdual Oger, Herve Toubon, Paul Sardini

Abstract:

Spectroscopic autoradiography is a method of interest for geological sample analysis. Indeed, researchers may face different issues such as radioelement identification and quantification in the field of environmental studies. Imaging gaseous ionization detectors find their place in geosciences for conducting specific measurements of radioactivity to improve the monitoring of natural processes using naturally-occurring radioactive tracers, but also for the nuclear industry linked to the mining sector. In geological samples, the location and identification of the radioactive-bearing minerals at the thin-section scale remains a major challenge as the detection limit of the usual elementary microprobe techniques is far higher than the concentration of most of the natural radioactive decay products. The spatial distribution of each decay product in the case of uranium in a geomaterial is interesting for relating radionuclides concentration to the mineralogy. The present study aims to provide spectroscopic autoradiography analysis method for measuring the initial energy of alpha particles with a parallel ionization multiplier gaseous detector. The analysis method has been developed thanks to Geant4 modelling of the detector. The track of alpha particles recorded in the gas detector allow the simultaneous measurement of the initial point of emission and the reconstruction of the initial particle energy by a selection based on the linear energy distribution. This spectroscopic autoradiography method was successfully used to reproduce the alpha spectra from a 238U decay chain on a geological sample at the thin-section scale. The characteristics of this measurement are an energy spectrum resolution of 17.2% (FWHM) at 4647 keV and a spatial resolution of at least 50 µm. Even if the efficiency of energy spectrum reconstruction is low (4.4%) compared to the efficiency of a simple autoradiograph (50%), this novel measurement approach offers the opportunity to select areas on an autoradiograph to perform an energy spectrum analysis within that area. This opens up possibilities for the detailed analysis of heterogeneous geological samples containing natural alpha emitters such as uranium-238 and radium-226. This measurement will allow the study of the spatial distribution of uranium and its descendants in geo-materials by coupling scanning electron microscope characterizations. The direct application of this dual modality (energy-position) of analysis will be the subject of future developments. The measurement of the radioactive equilibrium state of heterogeneous geological structures, and the quantitative mapping of 226Ra radioactivity are now being actively studied.

Keywords: alpha spectroscopy, digital autoradiography, mining activities, natural decay products

Procedia PDF Downloads 151

Authors: G. Torabian, A. Fathi, P. Valtchev, F. Dehghani

Abstract:

The superior polyphenol content of Sambucus nigra berries has high health potentials for the production of nutraceutical products. Numerous factors influence the polyphenol content of the final products including the berries’ source and the subsequent processing production steps. The aim of this study is to compare the polyphenol content of berries from two different sources and also to optimise the polyphenol extraction process from elderberries. Berries from source B obtained more acceptable physical properties than source A; a single berry from source B was double in size and weight (both wet and dry weight) compared with a source A berry. Despite the appropriate physical characteristics of source B berries, their polyphenolic profile was inferior; as source A berries had 2.3 fold higher total anthocyanin content, and nearly two times greater total phenolic content and total flavonoid content compared to source B. Moreover, the result of this study showed that almost 50 percent of the phenolic content of berries are entrapped within their skin and pulp that potentially cannot be extracted by press juicing. To address this challenge and to increase the total polyphenol yield of the extract, we used cold-shock blade grinding method to break the cell walls. The result of this study showed that using cultivars with higher phenolic content as well as using the whole fruit including juice, skin and pulp can increase polyphenol yield significantly; and thus, may boost the potential of using elderberries as therapeutic products.

Keywords: different sources, elderberry, grinding, juicing, polyphenols

Procedia PDF Downloads 294

Authors: Erkan Polat, Barlas Ozden Caglayan

Abstract:

By day-to-day developed techniques, it is possible to pass through larger openings by using smaller beam-column sections. Parallel to this trend, it is aimed to produce not only smaller but also economical and architecturally more attractive beams. This study aims to explain the structural behavior of arch steel beam reinforced by using post-tension cable. Due to the effect of post-stressed cable, the arch beam load carrying capacity increases and an optimized section in a smaller size can be obtained with a better architectural view. It also allows better mechanical and applicational solutions for buildings. For better understanding the behavior of the reinforced beam, steel beam and arch steel beam with post-tensioned cable are all modeled and analyzed by using SAP2000 Finite element computer program and compared with each other. Also, full scale test specimens were prepared to test for figuring out the structural behavior and compare the results with the computer model results. Test results are very promising. The similarity of the results between the test and computer analysis shows us that there are no extra knowledge and effort of engineer is needed to calculate such beams. The predicted (and proved by tests) beam carrying capacity is 35% higher than the unreinforced beam carrying capacity. Even just three full scale tests were completed, it is seen that the ratio (%35) may be increased ahead by adjusting the cable post-tension force of beams in much smaller sizes.

Keywords: arch steel beams, pre-stressed cables, finite element, specimen Test

Procedia PDF Downloads 165

Authors: S. Wiak, L. Szymanski, Z. Kolacinski, G. Raniszewski, L. Pietrzak, Z. Staniszewska

Abstract:

The term ‘cancer’ is given to a collection of related diseases that may affect any part of the human body. It is a pathological behaviour of cells with the potential to undergo abnormal breakdown in the processes that control cell proliferation, differentiation, and death of particular cells. Although cancer is commonly considered as modern disease, there are beliefs that drastically growing number of new cases can be linked to the extensively prolonged life expectancy and enhanced techniques for cancer diagnosis. Magnetic hyperthermia therapy is a novel approach to cancer treatment, which may greatly contribute to higher efficiency of the therapy. Employing carbon nanotubes as nanocarriers for magnetic particles, it is possible to decrease toxicity and invasiveness of the treatment by surface functionalisation. Despite appearing in recent years, magnetic particle hyperthermia has already become of the highest interest in the scientific and medical environment. The reason why hyperthermia therapy brings so much hope for future treatment of cancer lays in the effect that it produces in malignant cells. Subjecting them to thermal shock results in activation of numerous degradation processes inside and outside the cell. The heating process initiates mechanisms of DNA destruction, protein denaturation and induction of cell apoptosis, which may lead to tumour shrinkage, and in some cases, it may even cause complete disappearance of cancer. The factors which have the major impact on the final efficiency of the treatment include temperatures generated inside the tissues, time of exposure to the heating process, and the character of an individual cancer cell type. The vast majority of cancer cells is characterised by lower pH, persistent hypoxia and lack of nutrients, which can be associated to abnormal microvasculature. Since in healthy tissues we cannot observe presence of these conditions, they should not be seriously affected by elevation of the temperature. The aim of this work is to investigate the influence of iron content in iron filled Carbon Nanotubes on the desired nanoparticles for cancer therapy. In the article, the development and demonstration of the method and the model device for hyperthermic selective destruction of cancer cells are presented. This method was based on the synthesis and functionalization of carbon nanotubes serving as ferromagnetic material nanocontainers. The methodology of the production carbon- ferromagnetic nanocontainers (FNCs) includes the synthesis of carbon nanotubes, chemical, and physical characterization, increasing the content of a ferromagnetic material and biochemical functionalization involving the attachment of the key addresses. The ferromagnetic nanocontainers were synthesised in CVD and microwave plasma system. The research work has been financed from the budget of science as a research project No. PBS2/A5/31/2013.

Keywords: hyperthermia, carbon nanotubes, cancer colon cells, radio frequency field

Procedia PDF Downloads 122

Authors: Yoftahe Nigussie

Abstract:

This report presents a final year project pertaining to the design of Fire tube boiler for the purpose of producing saturated steam. The objective of the project is to produce saturated steam for different purpose with a capacity of 2000kg/h at 12bar design pressure by performing a design of a higher performance fire tube boiler that considered the requirements of cost minimization and parameters improvement. This is mostly done in selection of appropriate material for component parts, construction materials and production methods in different steps of analysis. In the analysis process, most of the design parameters are obtained by iterating with related formulas like selection of diameter of tubes with overall heat transfer coefficient optimization, and the other selections are also as like considered. The number of passes is two because of the size and area of the tubes and shell. As the analysis express by using heavy oil fuel no6 with a higher heating value of 44000kJ/kg and lower heating value of 41300kJ/kg and the amount of fuel consumed 140.37kg/hr. and produce 1610kw of heat with efficiency of 85.25%. The flow of the fluid is a cross flow because of its own advantage and the arrangement of the tube in-side the shell is welded with the tube sheet, and the tube sheet is attached with the shell and the end by using a gasket and weld. The design of the shell, using European Standard code section, is as like pressure vessel by considering the weight, including content and the supplementary accessories such as lifting lugs, openings, ends, man hole and supports with detail and assembly drawing.

Keywords: steam generation, external treatment, internal treatment, steam velocity

Procedia PDF Downloads 97

Authors: Asma Poursoroush

Abstract:

Solid-supported lipid bilayers are often used as a simple model for studies of biological membranes. The presence of a solid substrate that interacts attractively with lipid head-groups is expected to affect the phase behavior of the supported bilayer. Molecular dynamics simulations of a coarse-grained model are thus performed to investigate the phase behavior of supported one-component lipid bilayer membranes. Our results show that the attraction of the lipid head groups to the substrate leads to a phase behavior that is different from that of a free standing lipid bilayer. In particular, we found that the phase behaviors of the two leaflets are decoupled in the presence of a substrate. The proximal leaflet undergoes a clear gel-to-fluid phase transition at a temperature lower than that of a free standing bilayer, and that decreases with increasing strength of the substrate-lipid attraction. The distal leaflet, however, undergoes a change from a homogeneous liquid phase at high temperatures to a heterogeneous state consisting of small liquid and gel domains, with the average size of the gel domains that increases with decreasing temperature. While the chain order parameter of the proximal leaflet clearly shows a gel-fluid phase transition, the chain order parameter of the distal leaflet does not exhibit a clear phase transition. The decoupling in the phase behavior of the two leaflets is due to a non-symmteric lipid distribution in the two leaflets resulting from the presence of the substrate.

Keywords: membrane, substrate, molecular dynamics, simulation

Procedia PDF Downloads 195

Authors: Bright C. Opara, Gideon C. Uboegbulam

Abstract:

This study can be appreciated from the significant role culture exert in purchase decision of durable goods the world over. This study is motivated by cultural diversity in Nigeria and socio-economic changes that have taken place in the recent times. These call for the validation of similarly studies in order to formulate informed marketing strategies that will enhance purchase behaviour. This study therefore, is set out to examine the cultural influence in family purchase decision-making for durable goods in the three major ethnic groups in Nigeria (Hausa, Ibo, and Yoruba). The primary data was sourced using structured and semi-structured research questionnaire, while the secondary information was generated from existing / available relevant literature journals / periodicals. A judgmental sampling technique was used to determine the sample size of 300 households. The Analysis of Variance (ANOVA) statistical tool was used to test the hypotheses, with the aid of Statistical Packages for Social Sciences (SPSS) version 17.0. The finding showed that cultural influence on the family Purchase Decision of Durable Goods does not significantly differ in three ethnic groups, and that family Purchase Decision Making for Durable Goods does not significantly differ in the three ethnic groups. We therefore, conclude that culture do not really impact significantly on the purchase behaviour of the three ethnic groups in the Nigeria as it does in some others. However, there is need for marketers and marketing decision makers not to generalise the findings of this study. This is because of the significant role culture play in purchase behaviour which differs from one culture or country to another.

Keywords: cultural, durable goods, influence, purchase decision

Procedia PDF Downloads 393

Authors: Niladri Roy, M. Longshithung Patton

Abstract:

This paper is aimed at studying the structural response of circular hollow steel tubular (HST), concrete filled steel tubular (CFST), and reinforced cement concrete (RCC) stub columns when subjected to only axial compressive forces and also examining their comparative nature using finite element (FE) models. These results are further compared with the respective experimental results. FE software package ABAQUS 6.14 has been used for further parametric studies where a total of 108 FE models were modelled. The diameters of the HST, CFST, and RCC stub columns are kept as 100, 140, 180, and 220, with length to diameter ratio fixed at 3 to avoid end effects and flexural failure. To keep the same percentage of steel (by volume), the thicknesses of steel tubes in HST and CFST columns were varied in response to the change in diameter of the main reinforcement bar in RCC columns. M25 grade of concrete was used throughout. The objective is to compare the structural behaviour of HST, CFST, and RCC stub columns on the basis of their axial compressive load carrying capacity and failure modes. The studies show that filling the circular HST columns with concrete increases the Pu of the CCFST columns by 2.97 times. It was also observed that the Pu (HST) is about 0.72 times Pu (RCC) on average, and the Pu (CFST) is about 2.08 times Pu (RCC) on average. After the analysis and comparison, it has been proved that CFST has much more load carrying capacity than HST and RCC and also provides the same strength at a very less sectional size.

Keywords: HST columns, stub columns, CFST columns, RCC columns, finite element modeling, ABAQUS

Procedia PDF Downloads 100

Authors: Wan Azuati Wan Omar, Selva Rani John Jasudass, Siti Rohaiza Md. Saad

Abstract:

Introduction & objective: The objectives of this study were to assess patient’s knowledge of appropriate sublingual glyceryl trinitrate (GTN) use as well as to investigate how patients commonly store and carry their sublingual GTN tablets. Methodology: This was a cross-sectional survey, using a validated researcher-administered questionnaire. The study involved cardiac patients receiving sublingual GTN attending the outpatient and inpatient departments of Taiping Hospital, a non-academic public care hospital. The minimum calculated sample size was 92, but 100 patients were conveniently sampled. Respondents were interviewed on 3 areas, including demographic data, knowledge and use of sublingual GTN. Eight items were used to calculate each subject’s knowledge score and six items were used to calculate use score. Results: Of the 96 patients who consented to participate, majority (96.9%) were well aware of the indication of sublingual GTN. With regards to the mechanism of action of sublingual GTN, 73 (76%) patients did not know how the medication works. Majority of the patients (66.7%) knew about the proper storage of the tablet. In relation to the maximum number of sublingual GTN tablets that can be taken during each angina episode, 36.5% did not know that up to 3 tablets of sublingual GTN can be taken during each episode of angina. Fifty four (56.2%) patients were not aware that they need to replace sublingual GTN every 8 weeks after receiving the tablets. Majority (69.8%) of the patients demonstrated lack of knowledge with regards to the use of sublingual GTN as prevention of chest pain. Conclusion: Overall, patients’ knowledge regarding the self administration of sublingual GTN is still inadequate. The findings support the need for more frequent reinforcement of patient education, especially in the areas of preventive use, storage and drug stability.

Keywords: glyceryl trinitrate, knowledge, adherence, patient education

Procedia PDF Downloads 397

Authors: Laura M. Schwarz

Abstract:

WebQuests are an internet-based interactive teaching/learning tool and utilize a scaffolded methodology. WebQuests employ critical thinking, afford inquiry-based constructivist learning, and readily employ Bloom’s Taxonomy. WebQuests have generally been used as instructional technology tools in primary and secondary education and have more recently grown in popularity in higher education. The study of the efficacy of WebQuests as an instructional approach to learning, however, has been limited, particularly in the nursing education arena. The purpose of this mixed-methods study was to determine nursing students’ perceptions of the effectiveness of the Nursing WebQuest as a teaching/learning strategy for holistic nursing-related content. Quantitative findings (N=42) suggested that learners were active participants, used reflection, thought of new ideas, used analysis skills, discovered something new, and assessed the worth of something while taking part in the WebQuests. Qualitative findings indicated that participants found WebQuest positives as easy to understand and navigate; clear and organized; interactive; good alternative learning format, and used a variety of quality resources. Participants saw drawbacks as requiring additional time and work; and occasional failed link or link causing them to lose their location in the WebQuest. Recommendations include using larger sample size and more diverse populations from various programs and universities. In conclusion, WebQuests were found to be an effective teaching/learning tool as positively assessed by study participants.

Keywords: holistic nursing, nursing education, teaching/learning strategy, WebQuests

Procedia PDF Downloads 126

Authors: Nureni O. Adeboye, Dawud A. Agunbiade

Abstract:

This research attempts to investigate the effects of heteroscedasticity and periodicity in a Panel Data Regression Model (PDRM) by extending previous works on balanced panel data estimation within the context of fitting PDRM for Banks audit fee. The estimation of such model was achieved through the derivation of Joint Lagrange Multiplier (LM) test for homoscedasticity and zero-serial correlation, a conditional LM test for zero serial correlation given heteroscedasticity of varying degrees as well as conditional LM test for homoscedasticity given first order positive serial correlation via a two-way error component model. Monte Carlo simulations were carried out for 81 different variations, of which its design assumed a uniform distribution under a linear heteroscedasticity function. Each of the variation was iterated 1000 times and the assessment of the three estimators considered are based on Variance, Absolute bias (ABIAS), Mean square error (MSE) and the Root Mean Square (RMSE) of parameters estimates. Eighteen different models at different specified conditions were fitted, and the best-fitted model is that of within estimator when heteroscedasticity is severe at either zero or positive serial correlation value. LM test results showed that the tests have good size and power as all the three tests are significant at 5% for the specified linear form of heteroscedasticity function which established the facts that Banks operations are severely heteroscedastic in nature with little or no periodicity effects.

Keywords: audit fee lagrange multiplier test, heteroscedasticity, lagrange multiplier test, Monte-Carlo scheme, periodicity

Procedia PDF Downloads 141

Authors: Zahid Ahmad, Samia Yousaf

Abstract:

The main purpose of this study is to evaluate and assess the financial position, operating performance, and recent outlook of the companies. This study investigates the impact of capital structure, dividend policy and sustainability on the value of firms of textile spinning sector of Pakistan which is listed on Pakistan stock exchange. The panel data technique has been applied to this group of textile sector which is textile spinning. This study covers the last ten years of time period. All the data related to the variables have been collected from the annual reports and financial statements of the textile sector firms. There are differently related determinants to measure the capital structure which are fixed assets turnover ratio, debt ratio, equity ratio, debt to equity ratio, assets tangibility, and shareholder’s equity. Dividend policy is being measured by two determinants which are earning per share (EPS) and dividend payout ratio. Sustainability is being measured by three suitable factors which are sales growth, gross profit margin ratio and firm size. These are three independent variables and their determinants of this study. Value of firm is measured through the return on asset (ROA). Capital structure is at the top of the list among all the three variables. According to the results of this research work, somewhere all the three variables generates positive and significant effect on the firm’s performance and its growth.

Keywords: capital structure, dividend policy, panel data, sustainability

Procedia PDF Downloads 231

Authors: Wang Jianguo, Ding Xiao, Liu Dong, Wang Haiping, Yang Yanhui, Hu Yang

Abstract:

The hot deformation behavior of Inconel 718 alloy was studied by uniaxial compression tests under the deformation temperature of 940~1040℃ and strain rate of 0.001-10s⁻¹. The double cone compression (DCC) tests develop strains range from 30% to the 79% strain including all intermediate values of stains at different temperature (960~1040℃). DCC tests were simulated by finite element software which shown the strain and strain rates distribution. The result shows that the peak stress level of the alloy decreased with increasing deformation temperature and decreasing strain rate, which could be characterized by a Zener-Hollomon parameter in the hyperbolic-sine equation. The characterization method of hot processing window containing recrystallization volume fraction and average grain size was proposed for double cone compression test of uniform coarse grain, mixed crystal and uniform fine grain double conical specimen in hydraulic press and screw press. The results show that uniform microstructures can be obtained by low temperature with high deformation followed by high temperature with small deformation on the hydraulic press and low temperature, medium deformation, multi-pass on the screw press. The two methods were applied in industrial forgings process, and the forgings with uniform microstructure were obtained successfully.

Keywords: inconel 718 superalloy, hot processing windows, double cone compression, uniform microstructure

Procedia PDF Downloads 219

Authors: Jack R. McKenzie, Peter A. Appleby, Thomas House, Neil Walton

Abstract:

Cold-start is a notoriously difficult problem which can occur in recommendation systems, and arises when there is insufficient information to draw inferences for users or items. To address this challenge, a contextual bandit algorithm – the Fast Approximate Bayesian Contextual Cold Start Learning algorithm (FAB-COST) – is proposed, which is designed to provide improved accuracy compared to the traditionally used Laplace approximation in the logistic contextual bandit, while controlling both algorithmic complexity and computational cost. To this end, FAB-COST uses a combination of two moment projection variational methods: Expectation Propagation (EP), which performs well at the cold start, but becomes slow as the amount of data increases; and Assumed Density Filtering (ADF), which has slower growth of computational cost with data size but requires more data to obtain an acceptable level of accuracy. By switching from EP to ADF when the dataset becomes large, it is able to exploit their complementary strengths. The empirical justification for FAB-COST is presented, and systematically compared to other approaches on simulated data. In a benchmark against the Laplace approximation on real data consisting of over 670, 000 impressions from autotrader.co.uk, FAB-COST demonstrates at one point increase of over 16% in user clicks. On the basis of these results, it is argued that FAB-COST is likely to be an attractive approach to cold-start recommendation systems in a variety of contexts.

Keywords: cold-start learning, expectation propagation, multi-armed bandits, Thompson Sampling, variational inference

Procedia PDF Downloads 108

Authors: Samart Porncharoen, Nisa Pakvilai

Abstract:

The elevated levels of air pollutants in regional atmospheric environments is a significant problem that affects human health in Thailand, particularly in the Chao Phraya River Basin. Of concern are issues surrounding ambient air pollution such as particulate matter, gaseous pollutants and more specifically concerning air pollution along the river. Therefore, the spatio-temporal study of air pollution in this real environment can gain more accurate air quality data for making formalized environmental policy in river basins. In order to inform such a policy, a study was conducted over a period of January –December, 2015 to continually collect measurements of various pollutants in both urban and regional locations in the Chao Phraya River Basin. This study investigated the air pollutants in many diverse environments along the Chao Phraya River Basin, Thailand in 2015. Multivariate Analysis Techniques such as Principle Component Analysis (PCA) and Path analysis were utilised to classify air pollution in the surveyed location. Measurements were collected in both urban and rural areas to see if significant differences existed between the two locations in terms of air pollution levels. The meteorological parameters of various particulates were collected continually from a Thai pollution control department monitoring station over a period of January –December, 2015. Of interest to this study were the readings of SO2, CO, NOx, O3, and PM10. Results showed a daily arithmetic mean concentration of SO2, CO, NOx, O3, PM10 reading at 3±1 ppb, 0.5± 0.5 ppm, 30±21 ppb, 19±16 ppb, and 40±20 ug/m3 in urban locations (Bangkok). During the same time period, the readings for the same measurements in rural areas, Ayutthaya (were 1±0.5 ppb, 0.1± 0.05 ppm, 25±17 ppb, 30±21 ppb, and 35±10 ug/m3respectively. This show that Bangkok were located in highly polluted environments that are dominated source emitted from vehicles. Further, results were analysed to ascertain if significant seasonal variation existed in the measurements. It was found that levels of both gaseous pollutants and particle matter in dry season were higher than the wet season. More broadly, the results show that levels of pollutants were measured highest in locations along the Chao Phraya. River Basin known to have a large number of vehicles and biomass burning. This correlation suggests that the principle pollutants were from these anthropogenic sources. This study contributes to the body of knowledge surrounding ambient air pollution such as particulate matter, gaseous pollutants and more specifically concerning air pollution along the Chao Phraya River Basin. Further, this study is one of the first to utilise continuous mobile monitoring along a river in order to gain accurate measurements during a data collection period. Overall, the results of this study can be used for making formalized environmental policy in river basins in order to reduce the physical effects on human health.

Keywords: air pollution, Chao Phraya river basin, meteorology, seasonal variation, principal component analysis

Procedia PDF Downloads 285

Authors: P. Bhavya, P. R. Jayasree

Abstract:

This paper presents a low cost transformer isolated boost half bridge micro-inverter for single phase grid connected PV system. Since the output voltage of a single PV panel is as low as 20~50V, a high voltage gain inverter is required for the PV panel to connect to the single-phase grid. The micro-inverter has two stages, an isolated dc-dc converter stage and an inverter stage with a dc link. To achieve MPPT and to step up the PV voltage to the dc link voltage, a transformer isolated boost half bridge dc-dc converter is used. To output the synchronised sinusoidal current with unity power factor to the grid, a pulse width modulated full bridge inverter with LCL filter is used. Variable step size Maximum Power Point Tracking (MPPT) method is adopted such that fast tracking and high MPPT efficiency are both obtained. AC voltage as per grid requirement is obtained at the output of the inverter. High power factor (>0.99) is obtained at both heavy and light loads. This paper gives the results of computer simulation program of a grid connected solar PV system using MATLAB/Simulink and SIM Power System tool.

Keywords: boost-half-bridge, micro-inverter, maximum power point tracking, grid connection, MATLAB/Simulink

Procedia PDF Downloads 341

Authors: Masoumeh Kazemi

Abstract:

Depression is one of the most common mental disorders that damage mental health. In addition to mental distress, mental health damage affects other dimensions of human health, including physical and social health. According to the national study of diseases and injuries in Iran, the third health problem of the country is depression. The purpose of this study was to measure the level of depression in people referred to Karaj psychiatric treatment centers, and to investigate the relationship between depression and drug and alcohol consumption. The statistical population included 5000 people. Morgan table was used to determine the sample size. The research questions sought to identify the relationship between depression and factors such as drug and alcohol use, employment and marital status, and gender. Beck standard questionnaire was used to collect complete information. Cronbach's alpha coefficient was used to confirm the reliability of the questionnaire. To test research hypotheses, non-parametric methods of correlation coefficient, Spearman's rank, Mann-Whitney and Kruskal-Wallis tests were used. The results of using SPSS statistical software showed that there is a direct relationship between depression and drug and alcohol use. Also, the rate of depression was higher in women, widows and unemployed people. Finally, by conducting the present study, it is suggested that people use the following treatments in combination for effective recovery: 1. Cognitive Behavioral Therapy (CBT) 2. Interpersonal Therapy (IPT) 3. Treatment with appropriate medication 4. Special light therapy 5. Electric shock treatment (in acute and exceptional cases) 6. Self-help

Keywords: alcohol, depression, drug, Iran

Procedia PDF Downloads 57

Authors: Jummai Sekinat Seriki-Mosadolorun, Oyebamiji John Okesoto

Abstract:

School-aged children in Eti-Osa Local Government Area, Lagos State, were surveyed to determine their food habits, environmental exposures and nutritional status. The method used in this study was a descriptive survey. A systematic questionnaire and anthropometric measurement scales were utilized to compile the data. Information about the children's environment, diets, and demographics were collected using a questionnaire. The children's Body Mass Index (BMI) was calculated using anthropometric measuring scales. The sample size of 400 people was determined by a multi-stage sampling procedure. Chi-square test mean, and Analysis of Variance were used to examine the data. The study's findings suggested that the quality of the children’s natural environments was fairly satisfactory. The youngsters had an unhealthy diet consisting mostly of high-calorie items, including fufu/yam/Eba/pounded yam, biscuits, bread, vegetables, soups, meat, and sweetened drinks. The incidence of malnutrition among school-aged children varied dramatically. The children's environmental quality, eating pattern, and nutritional status were also significantly related to one another (p <0.005). The research came to the conclusion that historic structures should be updated with current technology to promote healthy growth in children, and it suggests that this be done as a matter of strategy.

Keywords: environmental quality, dietary pattern, nutritional status, school-aged children., dietary pattern, school-aged children, nutritional status

Procedia PDF Downloads 84

Authors: Tom O'Mahony

Abstract:

This article considers the design of a student-centered learning environment in engineering education. The learning environment integrates a number of components, including project-based learning, collaborative learning, two-stage assignments, active learning lectures, and a flipped-classroom. Together these elements place the individual learner and their learning at the center of the environment by focusing on understanding, enhancing relevance, applying learning, obtaining rich feedback, making choices, and taking responsibility. The evolution of this environment from 2014 to the present day is outlined. The impact of this environment on learners and their learning is evaluated via student questionnaires that consist of both open and closed-ended questions. The closed questions indicate that students found the learning environment to be really interesting and enjoyable (rated as 4.7 on a 5 point scale) and encouraged students to adopt a deep approach towards studying the course materials (rated as 4.0 on a 5 point scale). A content analysis of the open-ended questions provides evidence that the project, active learning lectures, and flipped classroom all contribute to the success of this environment. Furthermore, this analysis indicates that the two-stage assessment process, in which feedback is provided between a draft and final assignment, is the key component and the dominant theme. A limitation of the study is the small class size (less than 20 learners per year), but, to some degree, this is compensated for by the longitudinal nature of the study.

Keywords: deep approaches, formative assessment, project-based learning, student-centered learning

Procedia PDF Downloads 112

Authors: A. Dionísio, L. Roseiro, J. Fonseca, P. Nicolau

Abstract:

Thermography is a non-radiating and contact-free technology which can be used to monitor skin temperature. The efficiency and safety of thermography technology make it a useful tool for detecting and locating thermal changes in skin surface, characterized by increases or decreases in temperature. This work intends to be a contribution for the use of thermography as a methodology for evaluation of skin temperature in the context of orofacial biomechanics. The study aims to identify the oscillations of skin temperature in the left and right hemiface regions of the masseter muscle, during and after thermal stimulus, and estimate the time required to restore the initial temperature after the application of the stimulus. Using a FLIR T430sc camera, a data acquisition protocol was followed with a group of eight volunteers, aged between 22 and 27 years. The tests were performed in a controlled environment with the volunteers in a comfortably static position. The thermal stimulus involves the use of an ice volume with controlled size and contact surface. The skin surface temperature was recorded in two distinct situations, namely without further stimulus and with the additions of a stimulus obtained by a chewing gum. The data obtained were treated using FLIR Research IR Max software. The time required to recover the initial temperature ranged from 20 to 52 minutes when no stimulus was added and varied between 8 and 26 minutes with the chewing gum stimulus. These results show that recovery is faster with the addition of the stimulus and may guide clinicians regarding the pre and post-operative times with ice therapy, in the presence or absence of mechanical stimulus that increases muscle functions (e.g. phonetics or mastication).

Keywords: thermography, orofacial biomechanics, skin temperature, ice therapy

Procedia PDF Downloads 255

Authors: T. Yu, L. Audibert, J. F. Chaix, D. Komatitsch, V. Garnier, J. M. Henault

Abstract:

Linear Ultrasonic Techniques play a major role in Non-Destructive Evaluation (NDE) for civil engineering structures in concrete since they can meet operational requirements. Interpretation of ultrasonic measurements could be improved by a better understanding of ultrasonic wave propagation in a multiple scattering medium. This work aims to develop a 2D numerical model of ultrasonic wave propagation in a heterogeneous medium, like concrete, integrating the multiple scattering phenomena in SPECFEM software. The coherent field of multiple scattering is obtained by averaging numerical wave fields, and it is used to determine the effective phase velocity and attenuation corresponding to an equivalent homogeneous medium. First, this model is applied to one scattering element (a cylinder) in a homogenous medium in a linear-elastic system, and its validation is completed thanks to the comparison with analytical solution. Then, some cases of multiple scattering by a set of randomly located cylinders or polygons are simulated to perform parametric studies on the influence of frequency and scatterer size, concentration, and shape. Also, the effective properties are compared with the predictions of Waterman-Truell model to verify its validity. Finally, the mortar viscoelastic behavior is introduced in the simulation in order to considerer the dispersion and the attenuation due to porosity included in the cement paste. In the future, different steps will be developed: The comparisons with experimental results, the interpretation of NDE measurements, and the optimization of NDE parameters before an auscultation.

Keywords: attenuation, multiple-scattering medium, numerical modeling, phase velocity, ultrasonic measurements

Procedia PDF Downloads 275

Authors: Thi Thao Ninh, Yuri Trusov, José Ramón Botella

Abstract:

Heterotrimeric G proteins, comprised of three subunits, α, β and γ, are involved in signal transduction pathways that mediate a vast number of processes across the eukaryotic kingdom. 23 Gα subunits are present in humans whereas most plant genomes encode for only one canonical Gα. The disparity observed between Arabidopsis, rice, and maize Gα-deficient mutant phenotypes suggest that Gα functions have diversified between eudicots and monocots during evolution. Alternatively, since the only Gα mutations available in dicots have been produced in Arabidopsis, the possibility exists that this species might be an exception to the rule. In order to test this hypothesis, we studied the G protein α subunit (TGA1) in tomato. Four tga1 knockout lines were generated in tomato cultivar Moneymaker using CRISPR/Cas9. The tga1 mutants exhibit a number of auxin-related phenotypes including changes in leaf shape, reduced plant height, fruit size and number of seeds per fruit. In addition, tga1 mutants have increased sensitivity to abscisic acid during seed germination, reduced sensitivity to exogenous auxin during adventitious root formation from cotyledons and excised hypocotyl explants. Our results suggest that Gα mutant phenotypes in tomato are very similar to those observed in monocots, i.e. rice and maize, and cast doubts about the validity of using Arabidopsis as a model system for plant G protein studies.

Keywords: auxin-related phenotypes, CRISPR/Cas9, G protein α subunit, heterotrimeric G proteins, tomato

Procedia PDF Downloads 136

Authors: Gulnara Moldasheva

Abstract:

The research explores the relationship between management responsibility and corporate governance of listed companies in Kazakhstan. This research employs firm level data of randomly selected listed non-financial firms and firm level data “operational” financial sector, consisted from banking sector, insurance companies and accumulated pension funds using multivariate regression analysis under fixed effect model approach. Ownership structure includes institutional ownership, managerial ownership and private investor’s ownership. Management responsibility of the firm is expressed by the decision of the firm on amount of leverage. Results of the cross sectional panel study for non-financial firms showed that only institutional shareholding is significantly negatively correlated with debt to equity ratio. Findings from “operational” financial sector show that leverage is significantly affected only by the CEO/Chair duality and the size of financial institutions, and insignificantly affected by ownership structure. Also, the findings show, that there is a significant negative relationship between profitability and the debt to equity ratio for non-financial firms, which is consistent with pecking order theory. Generally, the found results suggest that corporate governance and a management responsibility play important role in corporate performance of listed firms in Kazakhstan.

Keywords: ownership, corporate governance, debt to equity ratio, corporate performance

Procedia PDF Downloads 343