Search results for: extremal dependence index

Authors: Chengfeng Fang, Mohamed Ali Sadakkathulla, Abdul Sheikh

Abstract:

Ultra-high-performance fiber reinforced concrete (UHPFRC) is a specially formulated cement-based composite characterized with an ultra-high compressive strength (f_c^’ = 240 MPa) and a low water-cement ratio (W/B= 0.2). With such material characteristics, UHPFRC is favored for the design and constructions of structures required high structural performance and slender geometries. Unlike conventional concrete, the structural performance of members manufactured with UHPFRC has not yet been fully studied, particularly, for UHPFRC columns with high slenderness. In this study, the behaviors of slender UHPFRC columns under concentric or eccentric load will be investigated both experimentally and numerically. Four slender UHPFRC columns were tested under eccentric loads with eccentricities, of 0 mm, 35 mm, 50 mm, and 85 mm, respectively, and one UHPFRC beam was tested under four-point bending. Finite element (FE) analysis was conducted with concrete damage plasticity (CDP) modulus to simulating the load-middle height or middle span deflection relationships and damage patterns of all UHPFRC members. Simulated results were compared against the experimental results and observation to gain the confidence of FE model, and this model was further extended to conduct parametric studies, which aim to investigate the effects of slenderness regarding failure modes and load-moment interaction relationships. Experimental results showed that the load bearing capacities of the slender columns reduced with an increase in eccentricity. Comparisons between load-middle height and middle span deflection relationships as well as damage patterns of all UHPFRC members obtained both experimentally and numerically demonstrated high accuracy of the FE simulations. Based on the available FE model, the following parametric study indicated that a further increase in the slenderness of column resulted in significant decreases in the load-bearing capacities, ductility index, and flexural bending capacities.

Keywords: eccentric loads, ductility index, RC column, slenderness, UHPFRC

Procedia PDF Downloads 130

Authors: Ahmadi, Iriansyah, Raihana Yahman

Abstract:

The giant freshwater prawn (Macrobrachium rosenbergii de Man, 1879) is a valuable species for fisheries and aquaculture, especially in Southeast Asia, including Indonesia due to their high market demand and potential for export. The growing demand for prawns is straining the sustainability of the Banjar Regency fishery. To ensure the long-term sustainability and economic viability of the prawn fishing in this region, it is imperative to implement evidence-based management practices. This requires comprehensive data on the Catch per Unit Effort (CPUE), Maximum Sustainable Yield (MSY) and the current rate of prawn resource exploitation. it analyzed five years of prawn catch data (2019-2023) obtained from South Kalimantan Marine and Fisheries Services. Fishing gears (e.g. hook & line and cast net) were first standardized with Fishing Power Index, and then calculated effort and MSY. The intercept (a) and the slope (b) values of regression curve were used to estimate the catch-maximum sustainable yield (CMSY) and optimal fishing effort (Fopt) levels within the framework of the Surplus Production Model. The estimated rates of resource utilization were then compared to the criteria of The National Commission of Marine Fish Stock Assessment. The findings showed that the CPUE value peaked in 2019 at 33.48 kg/trip, while the lowest value observed in 2022 at 5.12 kg/trip. The CMSY value was estimated to be 17,396 kg/year, corresponding to the Fopt level of 1,636 trips/year. The highest utilization rate was 56.90% recorded in 2020, while the lowest rate was observed in 2021 at 46.16%. The annual utilization rates were classified as “medium”, suggesting that increasing fishing effort by 45% could potentially maximize prawn catches at an optimum level. These findings provide a baseline for sustainable fisheries management in the region.

Keywords: giant prawns, CPUE, fishing power index, sustainable potential, utilization rate

Procedia PDF Downloads 16

Authors: Zeliha Ustun, Mustafa Ersoz

Abstract:

In the study, a traditional herbal supplement black cumin seed (Nigella sativa) oil properties has been studied to protect the main quality parameters by a new supplement application. Black cumin seed and its oil is used as a dietary supplement and preferred traditional remedy in Africa, Asia and Middle East for centuries. Now it has been consuming by millions of people in America and Europe as natural supplements and/or phytotherapeutic agents to support immune system, asthma, allergic rinnitis etc. by the scientists’ advices. With the study, it is aimed to prove that soft gelatin capsules are a new and more practical way of usage for Nigella sativa oil that has a longer stability. With the study soft gelatin capsules formulation has been developed to protect cold pressed black cumin seed oil physicochemical properties for a longer period. The product design has been developed in laboratory and implemented in pilot scale soft gelatin capsule manufacturing. Physicochemical properties (peroxide value, free fatty acids, fatty acid composition, refractive index, iodine value, saponification value, unsaponifiable matters) of Nigella sativa oil soft gelatin capsules and Nigella sativa oil in liquid form in amber glass bottles have been compared and followed for 8 months. The main parameters for capsules and liquid form found that for free fatty acids 2.29±0.03, 3.92±0.11 % oleic acid, peroxide 23.11±1.18, 27.85±2.50 meqO2/kg, refractive index at 20 0C 1.4738±0.00, 1.4737±0.00, soap 0 ppm, moisture and volatility 0.32±0.01, 0.36±0.01 %, iodine value 123.00±0.00, 122.00±0.00 wijs, saponification value 196.25±0.46, 194.13±0.35 mg KOH/g and unsaponifiable matter 7.72±0.13, 6.88±0.36 g/kg respectively. The main fatty acids are found that linoleic acid 56.17%, oleic acid 24.64%, palmitic acid 11,94 %. As a result, it is found that cold pressed Nigella sativa oil soft gelatin capsules physicochemical properties are more stable than the Nigella sativa oil stored in glass bottles.

Keywords: black cumin seed (Nigella sativa) oil, cold press, nutritional supplements, soft gelatin capsule

Procedia PDF Downloads 377

Authors: Nabil Abu-Heakal, Ismail Abo-Ghanema, Basma Hamed Merghani

Abstract:

The aim of this investigation is to study the effect of seasonal variations in Egypt on hematological parameters, reproductive and metabolic hormones of Egyptian buffalo-cows. This study lasted one year extending from December 2009 to November 2010 and was conducted on sixty buffalo-cows. Group of 5 buffalo-cows at estrus phase were selected monthly. Then, after blood sampling through tail vein puncture in the 2nd day after natural service, they were divided in two samples: one with anticoagulant for hematological analysis and the other without anticoagulant for serum separation. Results of this investigation revealed that the highest atmospheric temperature was in hot summer 32.61±1.12°C versus 26.18±1.67°C in spring and 19.92±0.70°C in winter season, while the highest relative humidity % was in winter season 43.50±1.60% versus 32.50±2.29% in summer season. The rise in temperature-humidity index from 63.73±1.29 in winter to 78.53±1.58 in summer indicates severe heat stress which is associated with significant reduction in total red blood cell count (3.20±0.15×106), hemoglobin concentration (8.83±0.43 g/dl), packed cell volume (30.73±0.12%), lymphocytes % (40.66±2.33 %), serum progesterone hormone concentration (0.56±0.03 ng/mll), estradiol17-B concentration (16.8±0.64 ng/ml), triiodothyronin (T3) concentration (2.33±0.33 ng/ml) and thyroxin hormone (T4) concentration (21.66±1.66 ng/ml), while hot summer resulted in significant increase in mean cell volume (96.55±2.25 fl), mean cell hemoglobin (30.81±1.33 pg), total white blood cell count (10.63±0.97×103), neutrophils % (49.66±2.33%), serum prolactin hormone (PRL) concentration (23.45±1.72 ng/ml) and cortisol hormone concentration (4.47±0.33 ng/ml) compared to winter season. There was no significant seasonal variation in mean cell hemoglobin concentration (MCHC). It was concluded that in Egypt there was a seasonal variation in atmospheric temperature, relative humidity, temperature humidity index (THI) and the rise in THI above the upper critical level (72 units), which, for lactating buffalo-cows in Egypt is the major constraint on buffalo-cows' hematological parameters and hormonal secretion that affects animal reproduction. Hence, we should improve climatic conditions inside the dairy farm to eliminate or reduce summer infertility.

Keywords: buffalo, climate change, Egypt, physiological parameters

Procedia PDF Downloads 660

Authors: Rachida Ouysse

Abstract:

This paper proposes a constrained principal components (CnPC) estimator for efficient estimation of large-dimensional factor models when errors are cross sectionally correlated and the number of cross-sections (N) may be larger than the number of observations (T). Although principal components (PC) method is consistent for any path of the panel dimensions, it is inefficient as the errors are treated to be homoskedastic and uncorrelated. The new CnPC exploits the assumption of bounded cross-sectional dependence, which defines Chamberlain and Rothschild’s (1983) approximate factor structure, as an explicit constraint and solves a constrained PC problem. The CnPC method is computationally equivalent to the PC method applied to a regularized form of the data covariance matrix. Unlike maximum likelihood type methods, the CnPC method does not require inverting a large covariance matrix and thus is valid for panels with N ≥ T. The paper derives a convergence rate and an asymptotic normality result for the CnPC estimators of the common factors. We provide feasible estimators and show in a simulation study that they are more accurate than the PC estimator, especially for panels with N larger than T, and the generalized PC type estimators, especially for panels with N almost as large as T.

Keywords: high dimensionality, unknown factors, principal components, cross-sectional correlation, shrinkage regression, regularization, pseudo-out-of-sample forecasting

Procedia PDF Downloads 150

Authors: Recep Gundogan, Turgay Dindaroglu, Hikmet Gunal, Mustafa Ulukavak, Ron Bingner

Abstract:

A majority of total soil losses in agricultural areas could be attributed to ephemeral gullies caused by heavy rains in conventionally tilled fields; however, ephemeral gully erosion is often ignored in conventional soil erosion assessments. Ephemeral gullies are often easily filled from normal soil tillage operations, which makes capturing the existing ephemeral gullies in croplands difficult. This study was carried out to determine topographic features, including slope and aspect composite topographic index (CTI) and initiation points of gully channels, using images obtained from unmanned aerial vehicle (UAV) images. The study area was located in Topcu stream watershed in the eastern Mediterranean Region, where intense rainfall events occur over very short time periods. The slope varied between 0.7 and 99.5%, and the average slope was 24.7%. The UAV (multi-propeller hexacopter) was used as the carrier platform, and images were obtained with the RGB camera mounted on the UAV. The digital terrain models (DTM) of Topçu stream micro catchment produced using UAV images and manual field Global Positioning System (GPS) measurements were compared to assess the accuracy of UAV based measurements. Eighty-one gully channels were detected in the study area. The mean slope and CTI values in the micro-catchment obtained from DTMs generated using UAV images were 19.2% and 3.64, respectively, and both slope and CTI values were lower than those obtained using GPS measurements. The total length and volume of the gully channels were 868.2 m and 5.52 m³, respectively. Topographic characteristics and information on ephemeral gully channels (location of initial point, volume, and length) were estimated with high accuracy using the UAV images. The results reveal that UAV-based measuring techniques can be used in lieu of existing GPS and total station techniques by using images obtained with high-resolution UAVs.

Keywords: aspect, compound topographic index, digital terrain model, initial gully point, slope, unmanned aerial vehicle

Procedia PDF Downloads 114

Authors: Mohamed Salaheldien Mohamed Alayat, Ahmed Mohamed Elsoudany, Roaa Abdulghani Sroge, Bayan Muteb Aldhahwani

Abstract:

Background: Neck pain is a common illness that could affect individual’s daily activities. Class IV laser with longer wavelength can stimulate tissues and penetrate more than the classic low-level laser therapy. Objectives: The aim of the study was to investigate the efficacy of class IV diode laser in the treatment of patients with chronic neck pain (CNP). Methods: Fifty-two patients participated and completed the study. Their mean age (SD) was 50.7 (6.2). Patients were randomized into two groups and treated with laser plus exercise (laser + EX) group and placebo laser plus exercise (PL+EX) group. Treatment was performed by Class IV laser in two phases; scanning and trigger point phases. Scanning to the posterior neck and shoulder girdle region with 4 J/cm2 with a total energy of 300 J applied to 75 cm2 in 4 minutes and 16 seconds. Eight trigger points on the posterior neck area were treated by 4 J/cm2 and the time of application was in 30 seconds. Both groups received exercise two times per week for 4 weeks. Exercises included range of motion, isometric, stretching, isotonic resisted exercises to the cervical extensors, lateral bending and rotators muscles with postural correction exercises. The measured variables were pain level using visual analogue scale (VAS), and neck functional activity using neck disability index (NDI) score. Measurements were taken at baseline and after 4 weeks of treatment. The level of statistical significance was set as p < 0.05. Results: There were significant decreases in post-treatment VAS and NDI in both groups as compared to baseline values. Laser + EX effectively decreased VAS (mean difference -6.5, p = 0.01) and NDI scores after (mean difference -41.3, p = 0.01) 4 weeks of treatment compared to PL + EX. Conclusion: Class IV laser combined with exercise is effective treatment for patients with CNP as compared to PL + EX therapy. The combination of laser + EX effectively increased functional activity and reduced pain after 4 weeks of treatment.

Keywords: chronic neck pain, class IV laser, exercises, neck disability index, visual analogue scale

Procedia PDF Downloads 314

Authors: Alena Zemanová, Jan Zeman, Michal Šejnoha

Abstract:

The polymer foil used for manufacturing of laminated glass members behaves in a viscoelastic manner with temperature dependence. This contribution aims at incorporating the time/temperature-dependent behavior of interlayer to our earlier elastic finite element model for laminated glass beams. The model is based on a refined beam theory: each layer behaves according to the finite-strain shear deformable formulation by Reissner and the adjacent layers are connected via the Lagrange multipliers ensuring the inter-layer compatibility of a laminated unit. The time/temperature-dependent behavior of the interlayer is accounted for by the generalized Maxwell model and by the time-temperature superposition principle due to the Williams, Landel, and Ferry. The resulting system is solved by the Newton method with consistent linearization and the viscoelastic response is determined incrementally by the exponential algorithm. By comparing the model predictions against available experimental data, we demonstrate that the proposed formulation is reliable and accurately reproduces the behavior of the laminated glass units.

Keywords: finite element method, finite-strain Reissner model, Lagrange multipliers, generalized Maxwell model, laminated glass, Newton method, Williams-Landel-Ferry equation

Procedia PDF Downloads 431

Authors: Poonam Sharma, Ankur Srivastav

Abstract:

Cities are complex and dynamic systems that constitute a significant challenge to urban planning. The increasing size of the built-up area owing to growing population pressure and economic growth have lead to massive Landuse/Landcover change resulted in the loss of natural habitat and thus reducing the green covers in urban areas. Urban environmental quality is influenced by several aspects, including its geographical configuration, the scale, and nature of human activities occurring and environmental impacts generated. Cities have transformed into complex and dynamic systems that constitute a significant challenge to urban planning. Cities and their sustainability are often discussed together as the cities stand confronted with numerous environmental concerns as the world becoming increasingly urbanized, and the cities are situated in the mesh of global networks in multiple senses. A rapid transformed urban setting plays a crucial role to change the green area of natural habitats. To examine the pattern of urban growth and to measure the Landuse/Landcover change in Gurgoan in Haryana, India through the integration of Geospatial technique is attempted in the research paper. Satellite images are used to measure the spatiotemporal changes that have occurred in the land use and land cover resulting into a new cityscape. It has been observed from the analysis that drastically evident changes in land use has occurred with the massive rise in built up areas and the decrease in green cover and therefore causing the sustainability of the city an important area of concern. The massive increase in built-up area has influenced the localised temperatures and heat concentration. To enhance the decision-making process in urban planning, a detailed and real world depiction of these urban spaces is the need of the hour. Monitoring indicators of key processes in land use and economic development are essential for evaluating policy measures.

Keywords: cityscape, geospatial techniques, green cover index, urban environmental quality, urban planning

Procedia PDF Downloads 277

Authors: Lukas Vierus, Thomas Schuster

Abstract:

A general framework is examined for dynamic tensor field tomography within an inhomogeneous medium characterized by refraction and absorption, treated as an inverse source problem concerning the associated transport equation. Guided by Fermat’s principle, the Riemannian metric within the specified domain is determined by the medium's refractive index. While considerable literature exists on the inverse problem of reconstructing a tensor field from its longitudinal ray transform within a static Euclidean environment, limited inversion formulas and algorithms are available for general Riemannian metrics and time-varying tensor fields. It is established that tensor field tomography, akin to an inverse source problem for a transport equation, persists in dynamic scenarios. Framing dynamic tensor tomography as an inverse source problem embodies a comprehensive perspective within this domain. Ensuring well-defined forward mappings necessitates establishing existence and uniqueness for the underlying transport equations. However, the bilinear forms of the associated weak formulations fail to meet the coercivity condition. Consequently, recourse to viscosity solutions is taken, demonstrating their unique existence within suitable Sobolev spaces (in the static case) and Sobolev-Bochner spaces (in the dynamic case), under a specific assumption restricting variations in the refractive index. Notably, the adjoint problem can also be reformulated as a transport equation, with analogous results regarding uniqueness. Analytical solutions are expressed as integrals over geodesics, facilitating more efficient evaluation of forward and adjoint operators compared to solving partial differential equations. Certainly, here's the revised sentence in English: Numerical experiments are conducted using a Nesterov-accelerated Landweber method, encompassing various fields, absorption coefficients, and refractive indices, thereby illustrating the enhanced reconstruction achieved through this holistic modeling approach.

Keywords: attenuated refractive dynamic ray transform of tensor fields, geodesics, transport equation, viscosity solutions

Procedia PDF Downloads 51

Authors: Awais Ahmad, Mostafa Muhammad Selim, Ali Abdullah Alderfasi

Abstract:

Water limitation is undoubtedly a critical environmental constraint limiting the crop production under arid and semiarid areas. Mung bean is susceptible to both drought and water logging stresses. Therefore, present study was conducted to assess the water deficit stress consequences of yield components and water use efficiency in Mung bean. A field experiment was conducted at Educational Farm, Crop Production Department, College of Food and Agricultural Sciences, Kind Saud University, Saudi Arabia. Trail comprised of four irrigation levels — total amount of irrigation divided into irrigation intervals — (3, 5, 7 and 9 days interval) and three Mung bean genotypes; Kawmay-1, VC-2010 and King from Egypt, Thailand and China respectively. Experiment was arranged under split plot design having irrigation as main while genotype as subplot treatment, and replicated thrice. Plant height, 100 seed weight, biological yield, seed yield, harvest index and water use efficiency were recorded at harvesting. Results revealed that decrease in irrigation have significantly hampered all the studied parameters. Mung bean genotypes have also shown significant differences for all parameters, whereas irrigation genotype interaction was highly significant for seed yield, harvest index and water use efficiency (WUE) while it was significant for biological yield. Plant height and 100 seed weight were recorded non-significant for irrigation genotype interaction. A statistically highly significant correlation among recorded parameters was observed. Minimum irrigation interval (3 days) significantly produced maximum values while VC-2010 comparatively performed better under low irrigation levels. It was concluded that Mung bean may be successfully adopted under Saudi Arabian climate but it needs high water or frequent irrigation, however, genotypic differences are a hope to develop some improved varieties with high water use efficiency.

Keywords: mung bean, irrigation intervals, water use efficiency, genotypes, yield

Procedia PDF Downloads 274

Authors: Lorryn Williams

Abstract:

This study will explore how the introduction of the for-profit social enterprise model affects the real lives of the individuals and communities that this model aims to help in South Africa. The congruence between organisational need construction and the real needs of beneficiaries, and whether the adoption of a profit driven model, such as social entrepreneurship, supports or discards these needs is key to answering the former question. By making use of qualitative methods, the study aims to collect empirical evidence that either supports the social entrepreneurship approach when compared to other programs such as vocational training programs or rejects it as less beneficial. It is the objective of this research to provide an answer to the question of whether the social enterprise model of conducting charity leaves the beneficiaries of non-profit organisations in a generally better or worse off position. The study will specifically explore the underlying assumptions the social entrepreneurship model makes, since the assumptions made concerning the uplifting effects it has on its beneficiaries may produce either real or assumed change for beneficiaries. The meaning of social cohesion and social capital for these organisations, the construction of beneficiary dependence and independence, the consideration of formal and informal economies beneficiaries engage in, and the extent to which sustainability is used as a brand, will be investigated. Through engaging the relevant literature, experts in the field of non-profit donorship and need implementation, organisations who have both adopted social enterprise programs and not, and most importantly, the beneficiaries themselves, it will be possible to provide answers to questions this study aims to answer.

Keywords: social enterprise, beneficiaries, profit driven model, non-profit organizations

Procedia PDF Downloads 140

Authors: Christopher S. Perez, Kendal C. Boyd

Abstract:

global suicide rates have decreased in recent decades, rates in the United States have increased by 35.2 percent since 1999.American Indians and Alaska Natives (AI/AN) have the highest rates of suicide in the U.S., with approximately 22 suicides per 100,000 people as of 2019. AI/AN have experienced significant historical trauma resulting in disproportionate rates of substance abuse and mental disorders. This literature review aimed to identify the demographic and clinical risk and protective factors for American Indians and Alaska Natives and provide an overview of suicidality in this population. The literature reflected varying definitions of suicidality depending on region, with some AI/AN tribesconceptualizing suicide through a spiritual framework, while others defined suicide in the biomedical sense. Furthermore, AI/AN adults and adolescents experienced higher rates of suicidal ideation when compared to other racial groups. Religious preference, sexual orientation, prior suicidal behavior, psychiatric admission, history of abuse, substance abuse, family history of mental illness, family history of substance abuse, family history of suicidal behaviors, domestic violence, and trauma were discussed as factors related to suicidality. Recommendations included increasing access to and utilization of mental health and medical services, culturally adapting suicide prevention programs to AI/AN communities, increasing support for LGBTQ+ AI/AN, providing opportunities that reinforce ethnic identity, and post-hospitalization follow-up care. The following databases were utilized to obtain peer-reviewed articles for this literature review: Complementary Index, Academic Search Premier, Science Direct, PsycInfo, Social Sciences Citation Index, PsycArticles, PubMed, EbscoHost, and PsycBooks. Articles that examined Native populations outside of the United States did not cite a primary source and/or were published before 1990 were excluded.

Keywords: alaska native, american indian, protective factors, risk factors, suicidality, suicide

Procedia PDF Downloads 100

Authors: Felipe Azocar Simonet, Luis Acosta Espejo

Abstract:

In this article, we will try to find an efficient boundary approximation for the bi-objective location problem with coherent coverage for two levels of hierarchy (CCLP). We present the mathematical formulation of the model used. Supported efficient solutions and unsupported efficient solutions are obtained by solving the bi-objective combinatorial problem through the weights method using a Lagrangean heuristic. Subsequently, the results are validated through the DEA analysis with the GEM index (Global efficiency measurement).

Keywords: coherent covering location problem, efficient frontier, lagragian relaxation, data envelopment analysis

Procedia PDF Downloads 334

Authors: Jiaqi Dong, Qing-Hua Qin, Yi Xiao

Abstract:

Some of the most fundamental challenges of elastic metamaterials (EMMs) optimization can be attributed to the high consumption of computational power resulted from finite element analysis (FEA) simulations that render the optimization process inefficient. Furthermore, due to the inherent mesh dependence of FEA, minuscule geometry features, which often emerge during the later stages of optimization, induce very fine elements, resulting in enormously high time consumption, particularly when repetitive solutions are needed for computing the objective function. In this study, a surrogate modelling algorithm is developed to reduce computational time in structural optimization of EMMs. The surrogate model is constructed based on a multilayer feedforward artificial neural network (ANN) architecture, trained with prepopulated eigenfrequency data prepopulated from FEA simulation and optimized through regime selection with genetic algorithm (GA) to improve its accuracy in predicting the location and width of the primary elastic band gap. With the optimized ANN surrogate at the core, a Nelder-Mead (NM) algorithm is established and its performance inspected in comparison to the FEA solution. The ANNNM model shows remarkable accuracy in predicting the band gap width and a reduction of time consumption by 47%.

Keywords: artificial neural network, machine learning, mechanical metamaterials, Nelder-Mead optimization

Procedia PDF Downloads 128

Authors: Xize Dai, Jian Hao, Claus Leth Bak, Gian Carlo Montanari, Huai Wang

Abstract:

Printed Circuit Board (PCB) is a critical component applicable to power electronics systems, especially for high-voltage applications involving several high-voltage and high-frequency SiC/GaN devices. The insulation system of PCB is facing more challenges from high-voltage and high-frequency stress that can alter the dielectric properties. Dielectric properties of the PCB insulation system also determine the electrical field distribution that correlates with intrinsic and extrinsic aging mechanisms. Hence, investigating the dielectric properties in the frequency domain of the PCB insulation system is a must. The paper presents the frequency-dependent, temperature-dependent, and voltage-dependent dielectric properties, permittivity, conductivity, and dielectric loss tangents of PCB insulation systems. The dielectric properties mechanisms associated with frequency, temperature, and voltage are revealed from the design perspective. It can be concluded that the dielectric properties of PCB in the frequency domain show a strong dependence on voltage, frequency, and temperature. The voltage-, frequency-, and temperature-dependent dielectric properties are associated with intrinsic conduction behavior and polarization patterns from the perspective of dielectric theory. The results may provide some reference for the PCB insulation system design in high voltage, high frequency, and high-temperature power electronics applications.

Keywords: electrical insulation system, dielectric properties, high voltage and frequency, printed circuit board

Procedia PDF Downloads 94

Authors: Siva Kumar Reddy, Anwesha Mukherjee, Abha Misra

Abstract:

Excellent energy absorption capability in carbon nanotubes (CNT) is shown in their bulk structure that behaves like super compressible foam. Furthermore, a tunable mechanical behavior of CNT foam is achieved using several methods like changing the concentration of precursors, polymer impregnation, non covalent functionalization of CNT microstructure etc. Influence of magnetic field on compressive behavior of magnetic CNT demonstrated an enhanced peak stress and energy absorption capability, which does not require any surface and structural modification of the foam. This presentation discusses the mechanical behavior of micro porous CNT foam that is impregnated in magnetic field responsive fluid. Magnetic particles are dispersed in a nonmagnetic fluid so that alignment of both particles and CNT could play a crucial role in controlling the stiffness of the overall structure. It is revealed that the compressive behavior of CNT foam critically depends on the fluid viscosity as well as magnetic field intensity. Both peak Stress and energy absorption in CNT foam followed a power law behavior with the increase in the magnetic field intensity. However, in the absence of magnetic field, both peak stress and energy absorption capability of CNT foam presented a linear dependence on the fluid viscosity. Hence, this work demonstrates the role magnetic filed in controlling the mechanical behavior of the foams prepared at nanoscale.

Keywords: carbon nanotubes, magnetic field, energy absorption capability and viscosity

Procedia PDF Downloads 304

Authors: R. Kishan, R. M. Sumant, S. Suhas, Arun Mahalingam

Abstract:

This paper mainly researched on influence of vortex generator on lift coefficient and drag coefficient, when vortex generator is mounted on a flat plate. Vented cylinders were used as vortex generators which intensify vortex shedding in the wake of the vented cylinder as compared to base line circular cylinder which ensures more attached flow and increases lift force of the system. Firstly vented cylinders were analyzed in commercial CFD software which is compared with baseline cylinders for different angles of attack and further variation of lift and drag forces were studied by varying Reynolds number to account for influence of turbulence and boundary layer in the flow. Later vented cylinders were mounted on a flat plate and variation of lift and drag coefficients was studied by varying angles of attack and studying the dependence of Reynolds number and dimensions of vortex generator on the coefficients. Mesh grid sensitivity is studied to check the convergence of the results obtained It was found that usage of vented cylinders as vortex generators increased lift forces with small variation in drag forces by varying angle of attack.

Keywords: CFD analysis, drag coefficient, FVM, lift coefficient, modeling, Reynolds number, simulation, vortex generators, vortex shedding

Procedia PDF Downloads 432

Authors: P. Lestinsky, D. Jecha, V. Brummer, P. Stehlik

Abstract:

Scrubbing by a liquid spraying is one of the most effective processes used for removal of fine particles and soluble gas pollutants (such as SO2, HCl, HF) from the flue gas. There are many configurations of scrubbers designed to provide contact between the liquid and gas stream for effectively capturing particles or soluble gas pollutants, such as spray plates, packed bed towers, jet scrubbers, cyclones, vortex and venturi scrubbers. The primary function of venturi scrubber is the capture of fine particles as well as HCl, HF or SO2 removal with effect of the flue gas temperature decrease before input to the absorption column. In this paper, sulfur dioxide (SO2) from flue gas was captured using new design replacing venturi scrubber (1st degree of wet scrubbing). The flue gas was prepared by the combustion of the carbon disulfide solution in toluene (1:1 vol.) in the flame in the reactor. Such prepared flue gas with temperature around 150 °C was processed in designed laboratory O-element scrubber. Water was used as absorbent liquid. The efficiency of SO2 removal, pressure drop and temperature drop were measured on our experimental device. The dependence of these variables on liquid-gas ratio was observed. The average temperature drop was in the range from 150 °C to 40 °C. The pressure drop was increased with increasing of a liquid-gas ratio, but not as much as for the common venturi scrubber designs. The efficiency of SO2 removal was up to 70 %. The pressure drop of our new designed wet scrubber is similar to commonly used venturi scrubbers; nevertheless the influence of amount of the liquid on pressure drop is not so significant.

Keywords: desulphurization, absorption, flue gas, modeling

Procedia PDF Downloads 399

Authors: Mohamad Reza Khodabakhsh

Abstract:

The present study investigated the effectiveness of attachment-based family therapy on maladaptive schemas and depressive symptoms of adolescence. This study was a quasi-experimental study, and a pre-test and post-test design with a control group were used. In this study, the study population included all adolescence. The sample consisted of 30 adolescents who were selected by the available sampling method. Then they were randomly divided into experimental (n = 15) and control (n = 15) groups. Data were collected in this study using the Beck Depression Inventory (1974) and the short form of Young's early maladaptive schema questionnaire (1988). After taking the pre-test, group implementation of family therapy based on attachment style was presented for 11 sessions of two and a half hours for two months in the experimental group. At the end of the sessions, both groups were retested, and the data were analyzed using analysis of covariance in SPSS-22 software. The results showed that attachment-based family therapy led to a significant reduction in maladaptive schemas, including emotional deprivation, rejection/abandonment, mistrust/abuse, social isolation, disability/shame, dependence/inadequacy, vulnerability/trauma, and depressive symptoms were compared to the control group. It can be concluded that this treatment has an effect on maladaptive schemas and symptoms of depression.

Keywords: attachment-based family therapy, maladaptive schemas, depressive symptoms, adolescence

Procedia PDF Downloads 106

Authors: Cláudia Alcoforado, Anabela Ribeiro

Abstract:

This paper is part of an ongoing PhD thesis. It seeks to develop a model to identify the spatial failures of the public transportation supply. In the construction of the model, it also seeks to detect the social needs arising from the disadvantage in transport. The case study is carried out for the Brazilian city of Recife. Currently, Recife has a population density of 7,039.64 inhabitants per km². Unfortunately, only 46.9% of urban households on public roads have adequate urbanization. Allied to this reality, the trend of the occupation of the poorest population is that of the peripheries, a fact that has been consolidated in Brazil and Latin America, thus burdening the families' income, since the greater the distances covered for the basic activities and consequently also the transport costs. In this way, there have been great impacts caused by the supply of public transportation to locations with low demand or lack of urban infrastructure. The model under construction uses methods such as Currie’s Gap Assessment associated with the London’s Public Transport Access Level, and the Public Transport Accessibility Index developed by Saghapour. It is intended to present the stage of the thesis with the spatial/need gaps of the neighborhoods of Recife already detected. The benefits of the geographic information system are used in this paper. It should be noted that gaps are determined from the transport supply indices. In this case, considering the presence of walking catchment areas. Still in relation to the detection of gaps, the relevant demand index is also determined. This, in turn, is calculated through indicators that reflect social needs. With the use of the smaller Brazilian geographical unit, the census sector, the model with the inclusion of population density in the study areas should present more consolidated results. Based on the results achieved, an analysis of transportation disadvantage will be carried out as a factor of social exclusion in the study area. It is anticipated that the results obtained up to the present moment, already indicate a strong trend of public transportation in areas of higher income classes, leading to the understanding that the most disadvantaged population migrates to those neighborhoods in search of employment.

Keywords: gap assessment, public transport supply, social exclusion, spatial gaps

Procedia PDF Downloads 182

Authors: Naridchaya Aberdour, Joanna Kao, Anne Miller, Timothy Shore, Richard Maher, Zhixin Liu

Abstract:

Background: COVID-19 has and continues to be a strain on healthcare globally, with the number of patients requiring hospitalization exceeding the level of medical support available in many countries. As chest x-rays are the primary respiratory radiological investigation, the Radiological Assessment of Lung Edema (RALE) score was used to quantify the extent of pulmonary infection on baseline imaging. Assessment of RALE score's reproducibility and associations with clinical outcome parameters were then evaluated to determine implications for patient management and prognosis. Methods: A retrospective study was performed with the inclusion of patients testing positive for COVID-19 on nasopharyngeal swab within a single Local Health District in Sydney, Australia and baseline x-ray imaging acquired between January to June 2020. Two independent Radiologists viewed the studies and calculated the RALE scores. Clinical outcome parameters were collected and statistical analysis was performed to assess RALE score reproducibility and possible associations with clinical outcomes. Results: A total of 78 patients met inclusion criteria with the age range of 4 to 91 years old. RALE score concordance between the two independent Radiologists was excellent (interclass correlation coefficient = 0.93, 95% CI = 0.88-0.95, p<0.005). Binomial logistics regression identified a positive correlation with hospital admission (1.87 OR, 95% CI= 1.3-2.6, p<0.005), oxygen requirement (1.48 OR, 95% CI= 1.2-1.8, p<0.005) and invasive ventilation (1.2 OR, 95% CI= 1.0-1.3, p<0.005) for each 1-point increase in RALE score. For each one year increased in age, there was a negative correlation with recovery (0.05 OR, 95% CI= 0.92-1.0, p<0.01). RALE scores above three were positively associated with hospitalization (Youden Index 0.61, sensitivity 0.73, specificity 0.89) and above six were positively associated with ICU admission (Youden Index 0.67, sensitivity 0.91, specificity 0.78). Conclusion: The RALE score can be used as a surrogate to quantify the extent of COVID-19 infection and has an excellent inter-observer agreement. The RALE score could be used to prognosticate and identify patients at high risk of deterioration. Threshold values may also be applied to predict the likelihood of hospital and ICU admission.

Keywords: chest radiography, coronavirus, COVID-19, RALE score

Procedia PDF Downloads 178

Authors: Kathryn H. Yull, Lina T. Al Kury, Frank Christopher Howarth

Abstract:

Cardiovascular diseases are frequently reported in patients with Type-1 Diabetes mellitus (DM). In addition to changes in cardiac muscle inotropy, electrical abnormalities are also commonly observed in these patients. In the present study, using streptozotocin (STZ) rat model of Type-1 DM, we have characterized the changes in L-type calcium channel activity in single atrioventricular nodal (AVN) myocytes. Ionic currents were recorded from AVN myocytes isolated from the hearts of control rats and from those with STZ-induced diabetes. Patch-clamp recordings were used to assess changes in cellular electrical activity in individual myocytes. Type-1 DM significantly altered the cellular characteristics of L-type calcium current (ICaL). A reduction in peak ICaL density was observed, with no corresponding changes in the activation parameters of the current. ICaL also exhibited faster time-dependent inactivation in AVN myocytes from diabetic rats. A negative shift in the voltage dependence of inactivation was also evident. These findings demonstrate that experimentally–induced type-1 DM significantly alters AVN L-type calcium channel cellular electrophysiology. The changes in ion channel activity may underlie the abnormalities in the cardiac electrical function that contribute to the high mortality levels in patients with DM.

Keywords: cardiac, ion-channel, diabetes, atrioventricular node, calcium channel

Procedia PDF Downloads 346

Authors: Abdelali Laid, Abid Hamza, Zeroukhi Houari, Sayah Naimi

Abstract:

This work relates to the study of the energy levels and the optimization of the Parameter intrinsic (a number of wells and their widths, width of barrier of potential, index of refraction etc.) and extrinsic (temperature, pressure) in the Structure laser diode containing the structure GaInP. The methods of calculation used; - method of the empirical pseudo potential to determine the electronic structures of bands, - graphic method for optimization. The found results are in concord with those of the experiment and the theory.

Keywords: semi-conductor, GaInP/AlGaInP, pseudopotential, energy, alliages

Procedia PDF Downloads 492

Authors: Moatlhodi Wise Letshwenyo, Lesedi Lebogang

Abstract:

Botswana is an arid country that needs to start reusing wastewater as part of its water security plan. Pilot scale slow sand filtration in combination with roughing filter was investigated for the treatment of effluent from Botswana International University of Science and Technology to meet Botswana irrigation standards. The system was operated at hydraulic loading rates of 0.04 m/hr and 0.12 m/hr. The results show that the system was able to reduce turbidity from 262 Nephelometric Turbidity Units to a range between 18 and 0 Nephelometric Turbidity Units which was below 30 Nephelometric Turbidity Units threshold limit. The overall efficacy ranged between 61% and 100%. Suspended solids, Biochemical Oxygen Demand, and Chemical Oxygen Demand removal efficiency averaged 42.6%, 45.5%, and 77% respectively and all within irrigation standards. Other physio-chemical parameters were within irrigation standards except for bicarbonate ion which averaged 297.7±44 mg L^-1 in the influent and 196.22±50 mg L^-1 in the effluent which was above the limit of 92 mg L^-1, therefore averaging a reduction of 34.1% by the system. Total coliforms, fecal coliforms, and Escherichia coli in the effluent were initially averaging 1.1 log counts, 0.5 log counts, and 1.3 log counts respectively compared to corresponding influent log counts of 3.4, 2.7 and 4.1, respectively. As time passed, it was observed that only roughing filter was able to reach reductions of 97.5%, 86% and 100% respectively for faecal coliforms, Escherichia coli, and total coliforms. These organism numbers were observed to have increased in slow sand filter effluent suggesting multiplication in the tank. Water quality index value of 22.79 for the physio-chemical parameters suggests that the effluent is of excellent quality and can be used for irrigation purposes. However, the water quality index value for the microbial parameters (1820) renders the quality unsuitable for irrigation. It is concluded that slow sand filtration in combination with roughing filter is a viable option for the treatment of secondary effluent for reuse purposes. However, further studies should be conducted especially for the removal of microbial parameters using the system.

Keywords: irrigation, slow sand filter, turbidity, wastewater reuse

Procedia PDF Downloads 153

Authors: Faiz N. K. Yusufi, Aquil Ahmed, Jamal Ahmad

Abstract:

Diabetes in India is growing at an alarming rate and the complications caused by it need to be controlled. Coronary heart disease (CHD) is one of the complications that will be discussed for prediction in this study. India has the second most number of diabetes patients in the world. To the best of our knowledge, there is no CHD risk score for Indian type 2 diabetes patients. Any form of CHD has been taken as the event of interest. A sample of 750 was determined and randomly collected from the Rajiv Gandhi Centre for Diabetes and Endocrinology, J.N.M.C., A.M.U., Aligarh, India. Collected variables include patients data such as sex, age, height, weight, body mass index (BMI), blood sugar fasting (BSF), post prandial sugar (PP), glycosylated haemoglobin (HbA1c), diastolic blood pressure (DBP), systolic blood pressure (SBP), smoking, alcohol habits, total cholesterol (TC), triglycerides (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), physical activity, duration of diabetes, diet control, history of antihypertensive drug treatment, family history of diabetes, waist circumference, hip circumference, medications, central obesity and history of CHD. Predictive risk scores of CHD events are designed by cox proportional hazard regression. Model calibration and discrimination is assessed from Hosmer Lemeshow and area under receiver operating characteristic (ROC) curve. Overfitting and underfitting of the model is checked by applying regularization techniques and best method is selected between ridge, lasso and elastic net regression. Youden’s index is used to choose the optimal cut off point from the scores. Five year probability of CHD is predicted by both survival function and Markov chain two state model and the better technique is concluded. The risk scores for CHD developed can be calculated by doctors and patients for self-control of diabetes. Furthermore, the five-year probabilities can be implemented as well to forecast and maintain the condition of patients.

Keywords: coronary heart disease, cox proportional hazard regression, ROC curve, type 2 diabetes Mellitus

Procedia PDF Downloads 219

Authors: Vikram Kalekar

Abstract:

Modern Internet Protocol (IP) networks deploy traditional and modern Quality of Service (QoS) management methods to ensure the smooth flow of network packets during regular operations. SDN (Software-defined networking) networks have also made headway into better service delivery by means of novel QoS methodologies. While many of these techniques are experimental, some of them have been tested extensively in controlled environments, and few of them have the potential to be deployed widely in the industry. With this survey, we plan to analyze the approaches to QoS and resource allocation in SDN, and we will try to comment on the possible improvements to QoS management in the context of SDN.

Keywords: QoS, policy, congestion, flow management, latency, delay index terms-SDN, delay

Procedia PDF Downloads 193

Authors: Balgaisha G. Mukanova, Yelbek B. Utepov, Aida G. Nazarova, Alisher Z. Imanov

Abstract:

The problem of identifying local noise sources on a construction site using a sensor system is considered. Mathematical modeling of detected signals on sensors was carried out, considering signal decay and signal delay time between the source and detector. Recordings of noises produced by construction tools were used as a dependence of noise on time. Synthetic sensor data was constructed based on these data, and a model of the propagation of acoustic waves from a point source in the three-dimensional space was applied. All sensors and sources are assumed to be located in the same plane. A source localization method is checked based on the signal time delay between two adjacent detectors and plotting the direction of the source. Based on the two direct lines' crossline, the noise source's position is determined. Cases of one dominant source and the case of two sources in the presence of several other sources of lower intensity are considered. The number of detectors varies from three to eight detectors. The intensity of the noise field in the assessed area is plotted. The signal of a two-second duration is considered. The source is located for subsequent parts of the signal with a duration above 0.04 sec; the final result is obtained by computing the average value.

Keywords: acoustic model, direction of arrival, inverse source problem, sound localization, urban noises

Procedia PDF Downloads 62

Authors: Musa Momoh, A. U. Moreh, A. M. Bayawa, Sanusi Abdullahi, I. Atiku

Abstract:

In this study, thin films of ZnO were synthesized by two techniques namely RF sputtering and spray pyrolysis. The films were deposited on corning glass. The primary materials used are 99.99% pure. The optical and structural properties of the samples were studied. It has been noted that the samples deposited by Spray pyrolysis have and average transmittance, refractive index and extinction coefficient as 80-90%, 1.33-1.44 and 13.11-27.52 respectively. Those deposited by sputtering method are 34-80%, 1.51-1.52 and 3.15-3.28. The XRD patterns of the samples show that they are polycrystalline.

Keywords: zinc oxide, spray pyrolysis, rf sputtering, optical properties, electrical properties

Procedia PDF Downloads 266

Authors: Kemal Çomakli, Uğur Çakir, Ayşegül Çokgez Kuş, Erol Şahin

Abstract:

Kind of energy that buildings need changes in various types, like heating energy, cooling energy, electrical energy and thermal energy for hot top water. Usually the processes or systems produce thermal energy causes emitting pollutant emissions while they produce heat because of fossil fuels they use. A lower consumption of thermal energy will contribute not only to a reduction in the running costs, but also in the reduction of pollutant emissions that contribute to the greenhouse effect and a lesser dependence of the hospital on the external power supply. Cogeneration or CHP (Combined heat and Power) is the system that produces power and usable heat simultaneously. Combined production of mechanical or electrical and thermal energy using a simple energy source, such as oil, coal, natural or liquefied gas, biomass or the sun; affords remarkable energy savings and frequently makes it possible to operate with greater efficiency when compared to a system producing heat and power separately. Because of the life standard of humanity in new age, energy sources must be continually and best qualified. For this reason the installation of a system for the simultaneous generation of electrical, heating and cooling energy would be one of the best solutions if we want to have qualified energy and reduce investment and operating costs and meet ecological requirements. This study aims to bring out the contributions of cogeneration systems to the environment and sustainability by saving the energy and reducing the emissions.

Keywords: sustainability, cogeneration systems, energy economy, energy saving

Procedia PDF Downloads 517