Search results for: relative density

Authors: Yujiang Wu

Abstract:

As electrical machine (e-machine) power density re-querulents become more stringent in vehicle electrification, mounting a temperature sensor for e-machine stator windings becomes increasingly difficult. This can lead to higher manufacturing costs, complicated harnesses, and reduced reliability. In this paper, we propose a deep-learning method for predicting electric machine winding temperature, which can either replace the sensor entirely or serve as a backup to the existing sensor. We compare the performance of our method, the stateful long short-term memory networks (LSTM) with truncated backpropagation through time (TBTT), with that of linear regression, as well as stateless LSTM with/without residual connection. Our results demonstrate the strength of combining stateful LSTM and TBTT in tackling nonlinear time series prediction problems with long sequence lengths. Additionally, in industrial applications, high-temperature region prediction accuracy is more important because winding temperature sensing is typically used for derating machine power when the temperature is high. To evaluate the performance of our algorithm, we developed a temperature-stratified MSE. We propose a simple but effective data preprocessing trick to improve the high-temperature region prediction accuracy. Our experimental results demonstrate the effectiveness of our proposed method in accurately predicting winding temperature, particularly in high-temperature regions, while also reducing manufacturing costs and improving reliability.

Keywords: deep learning, electrical machine, functional safety, long short-term memory networks (LSTM), thermal management, time series prediction

Procedia PDF Downloads 93

Authors: Masoud Ghaemi, Mohammadjafar Hedayati, Faezeh Yousefzadeh, Hoseinali Heydarzadeh

Abstract:

Careful monitoring in the earth dams to measure deformation caused by settlement and movement has always been a concern for engineers in the field. In order to measure settlement and deformation of earth dams, usually, the precision instruments of settlement set and combined Inclinometer that is commonly referred to IS instrument will be used. In some dams, because the thickness of alluvium is high and there is no possibility of alluvium removal (technically and economically and in terms of performance), there is no possibility of placing the end of IS instrument (precision instruments of Inclinometer-settlement set) in the rock foundation. Inevitably, have to accept installing pipes in the weak and deformable alluvial foundation that leads to errors in the calculation of the actual settlement (absolute settlement) in different parts of the dam body. The purpose of this paper is to present new and refine criteria for predicting settlement and deformation in earth dams. The study is based on conditions in three dams with a deformation quite alluvial (Agh Chai, Narmashir and Gilan-e Gharb) to provide settlement criteria affected by the alluvial foundation. To achieve this goal, the settlement of dams was simulated by using the finite difference method with FLAC3D software, and then the modeling results were compared with the reading IS instrument. In the end, the caliber of the model and validate the results, by using regression analysis techniques and scrutinized modeling parameters with real situations and then by using MATLAB software and CURVE FITTING toolbox, new criteria for the settlement based on elasticity modulus, cohesion, friction angle, the density of earth dam and the alluvial foundation was obtained. The results of these studies show that, by using the new criteria measures, the amount of settlement and deformation for the dams with alluvial foundation can be corrected after instrument readings, and the error rate in reading IS instrument can be greatly reduced.

Keywords: earth-fill dam, foundation, settlement, finite difference, MATLAB, curve fitting

Procedia PDF Downloads 188

Authors: Imtiaz Ali, Krishnan Jayaraman, Debes Bhattacharyya

Abstract:

Soybean concentrate is abundant material and renewable product that is recently been explored as an alternative to conventional formaldehyde based resins in wood based products. The main goal of this study is to evaluate the technical feasibility of manufacturing environment friendly MDF panels from renewable resources. The panels are made by using kenaf bast fibers (KB) as wood substitute and soy based adhesive as bonding material. Second order response surface regression models are used to understand the effects and interactions of resin content (RC) and pressing time (PT) on the mechanical and water soaking properties of kenaf panels. The mechanical and water soaking properties are significantly improved as the RC increased and reached at the highest level at maximum resin loading (12%). The effect of pressing time is significant in the first phase when the pressing time increased from 4 to 6 min; however the effect was not as significant when pressing time further increased to 8 min. The second order regression equations further confirm that the variation in process parameters has strong relationship with the physciomechanical properties. The MDF panels the minimum requirements of internal bond strength, modulus of rupture and modulus of elasticity as recommended by US wood MDF standard specifications for G110, G120, G130 and G140 grade MDF panels. However, the thickness swelling results are considerably poorer than the recommended values of general purpose standard requirements. This deficiency can be counterbalanced by the advantage of being formaldehyde free panels made from renewable sources and by making them suitable alternative for less humid environment applications.

Keywords: kenaf, Medium density fibreboard, soy adhesive, mechanical properties, water soaking properties

Procedia PDF Downloads 369

Authors: Christina Williams, Mehari Weldemariam, Ann M. Farese, Thomas J. MacVittie, Maureen A. Kane

Abstract:

Radiation exposure results in dose-dependent and time-dependent multi-organ damage. Drug development of medical countermeasures (MCM) for radiation-induced injury occurs under the FDA Animal Rule because human efficacy studies are not ethical or feasible. The FDA Animal Rule requires the representation of both sexes and describes several uses for biomarkers in MCM drug development studies. Currently, MCMs are limited and there is no FDA-approved biomarker for any radiation injury. Sex as a variable is essential to identifying biomarkers and developing effective MCMs for acute radiation exposure (ARS) and delayed effects of acute radiation exposure (DEARE). These studies aim to address the death of information on sex differences that have not been determined by studies that included only male, single-sex cohorts. Studies have reported differences in radiosensitivity according to sex. As such, biomarker discovery for radiation-induced damage must consider sex as a variable. This study evaluated the plasma proteomic profile of Rhesus macaque non-human primates after different exposures and doses, as well as time points after radiation. Exposures and doses included total body irradiation between 5-7.5 Gy and partial body irradiation with 5% bone marrow sparing at 9, 9.5 and 10 Gy. Timepoints after irradiation included days 1, 3, 60, and 180, which encompassed both acute radiation syndromes and delayed effects of acute radiation exposure. Bottom-up proteomic analyses of plasma included equal numbers of males and females. In the control animals, few proteomic differences are observed between the sexes. In the irradiated animals, there are a few sex differences, with changes mostly consisting of proteins upregulated in the female animals. Multiple canonical pathways were upregulated in irradiated animals relative to the control animals when subjected to pathway analysis, but differential responses between the sexes are limited. These data provide critical baseline differences according to sex and establish sex differences in non-human primate models relevant to drug development of MCM under the FDA Animal Rule.

Keywords: ionizing radiation, sex differences, plasma proteomics, biomarker discovery

Procedia PDF Downloads 82

Authors: Faizan Ali, Dayu Zhou, Xiaohua Liu, Tony Schenk, Johannes Muller, Uwe Schroeder

Abstract:

Recently, the ferroelectricity (FE) and anti-ferroelectricity (AFE) introduced in so-called 'high-k dielectric' HfO₂ material incorporated with various dopants (Si, Gd, Y, Sr, Gd, Al, and La, etc.), HfO₂-ZrO₂ solid-solution, Al or Si-doped Hf₀.₅Zr₀.₅O₂ and even undoped HfO₂ thin films. The origin of FE property was attributed to the formation of a non-centrosymmetric orthorhombic (o) phase of space group Pbc2₁. To the author’s best knowledge, AFE property was observed only in HfO₂ doped with a certain amount of Si, Al, HfₓZr₁₋ₓO₂ (0 ≤ x < 0.5), and in Si or Al-doped Hf₀.₅Zr₀.₅O₂. The origin of the anti-ferroelectric behavior is an electric field induced phase transition between the non-polar tetragonal (t) and the polar ferroelectric orthorhombic (o) phase. Compared with the significant amount of studies for the FE properties in the context of non-volatile memories, AFE properties of HfO₂-based and HfₓZr₁₋ₓO₂ (HZO) thin films have just received attention recently for energy-related applications such as electrocaloric cooling, pyroelectric energy harvesting, and electrostatic energy storage. In this work, energy storage and solid state cooling properties of Si-doped HfO₂ AFE thin films are investigated. Owing to the high field-induced polarization and slim double hysteresis, an extremely large Energy storage density (ESD) value of 61.2 J cm⁻³ is achieved at 4.5 MV cm⁻¹ with high efficiency of ~65%. In addition, the ESD and efficiency exhibit robust thermal stability in 210-400 K temperature range and excellent endurance up to 10⁹ times of charge/discharge cycling at a very high electric field of 4.0 MV cm⁻¹. Similarly, for solid-state cooling, the maximum adiabatic temperature change (

Keywords: thin films, energy storage, endurance, solid state cooling, anti-ferroelectric

Procedia PDF Downloads 124

Authors: Leon Mortari

Abstract:

The Metropolitan East region of Rio de Janeiro state, Brazil, faces a historic water scarcity. Among the alternatives studied to solve this situation, the possibility of adduction of the available water in the reservoir Lagoa de Juturnaíba to supply the region's municipalities stands out. The allocation of a linear engineering project must occur through an evaluation of different aspects, such as altitude, slope, proximity to roads, distance from watercourses, land use and occupation, and physical and chemical features of the soil. This work aims to apply a multi-criteria model that combines geoprocessing techniques, decision-making, and geometric search algorithm to optimize a hypothetical adductor system in the scenario of expanding the water supply system that serves this region, known as Imunana-Laranjal, using the Lagoa de Juturnaíba as the source. It is proposed in this study, the construction of a spatial database related to the presented evaluation criteria, treatment and rasterization of these data, and standardization and reclassification of this information in a Geographic Information System (GIS) platform. The methodology involves the integrated analysis of these criteria, using their relative importance defined by weighting them based on expert consultations and the Analytic Hierarchy Process (AHP) method. Three approaches are defined for weighting the criteria by AHP: the first treats all criteria as equally important, the second considers weighting based on a pairwise comparison matrix, and the third establishes a hierarchy based on the priority of the criteria. For each approach, a distinct group of weightings is defined. In the next step, map algebra tools are used to overlay the layers and generate cost surfaces, that indicates the resistance to the passage of the adductor route, using the three groups of weightings. The Dijkstra algorithm, a geometric search algorithm, is then applied to these cost surfaces to find an optimized path within the geographical space, aiming to minimize resources, time, investment, maintenance, and environmental and social impacts.

Keywords: geometric search algorithm, GIS, pipeline, route optimization, spatial multi-criteria analysis model

Procedia PDF Downloads 21

Authors: Tanu Khanuja, Harikrishnan N. Unni

Abstract:

Head is the most vulnerable part of human body and may cause severe life threatening injuries. As the in vivo brain response cannot be recorded during injury, computational investigation of the head model could be really helpful to understand the injury mechanism. Majority of the physical damage to living tissues are caused by relative motion within the tissue due to tensile and shearing structural failures. The present Finite Element study focuses on investigating intracranial pressure and stress/strain distributions resulting from impact loads on various sites of human head. This is performed by the development of the 3D model of a human head with major segments like cerebrum, cerebellum, brain stem, CSF (cerebrospinal fluid), and skull from patient specific MRI (magnetic resonance imaging). The semi-automatic segmentation of head is performed using AMIRA software to extract finer grooves of the brain. To maintain the accuracy high number of mesh elements are required followed by high computational time. Therefore, the mesh optimization has also been performed using tetrahedral elements. In addition, model validation with experimental literature is performed as well. Hard tissues like skull is modeled as elastic whereas soft tissues like brain is modeled with viscoelastic prony series material model. This paper intends to obtain insights into the severity of brain injury by analyzing impacts on frontal, top, back, and temporal sites of the head. Yield stress (based on von Mises stress criterion for tissues) and intracranial pressure distribution due to impact on different sites (frontal, parietal, etc.) are compared and the extent of damage to cerebral tissues is discussed in detail. This paper finds that how the back impact is more injurious to overall head than the other. The present work would be helpful to understand the injury mechanism of traumatic brain injury more effectively.

Keywords: dynamic impact analysis, finite element analysis, intracranial pressure, MRI, traumatic brain injury, von Misses stress

Procedia PDF Downloads 156

Authors: Syed Muhammad Basit Ali, Usama Saleem, Irtiza Ali

Abstract:

Internal combustion engines have been pioneers in the aviation industry, use of piston engines for aircraft propulsion, from propeller-driven bi-planes to turbo-prop, commercial, and cargo airliners. To provide an adequate amount of thrust piston engine rotates the propeller at a specific rpm, allowing enough mass airflow. Thrust is the only forward-acting force of an aircraft that helps heavier than air bodies to fly, depending on the mathematical model and variables included in that with the correct measurement. Test-benches have been a bench-mark in the aerospace industry to analyse the results before a flight, having paramount significance in reliability and safety engineering, depending on the mathematical model and variables included in that with the correct measurement. Calculation of thrust from a piston engine also depends on environmental changes, the diameter of the propeller, and the density of air. The project would be centered on piston engines used in the aviation industry for light aircraft and UAVs. A static thrust test bench involves various units, each performing a designed purpose to monitor and display. Static thrust tests are performed on the ground, and safety concerns hold paramount importance. The execution of this study involves research, design, manufacturing, and results based on reverse engineering initiating from virtual design, analytical analysis, and simulations. The final evaluation of results gathered from various methods such as co-relation between conventional mass-spring and digital loadcell. On average, we received 17.5kg of thrust (25+ engine run-ups – around 40 hours of engine run), only 10% deviation from analytically calculated thrust –providing 90% accuracy.

Keywords: aviation, aeronautics, static thrust, test bench, aircraft maintenance

Procedia PDF Downloads 399

Authors: Joao Paulo Matheus, Renan Fangel

Abstract:

Rheumatoid arthritis is a chronic, inflammatory, systemic and progressive disease that affects the synovial joints bilaterally, causing definitive orthopedic damage. It has a higher prevalence in postmenopausal female patients. It is a disabling disease that causes joint deformities that may compromise the functionality of the affected segment. The aim of this study was to evaluate the influence of low-intensity therapeutic laser on the perception of pain and quality of life in patients with rheumatoid arthritis. This is a randomized clinical study involving 6 women with a mean age of 56.8+6.3 years. Exclusion criteria: patients with acute pain, chronic infectious disease, underlying acute or chronic underlying disease. An AsGaAl laser with 808nm wavelength, 100mW power, beam output area of 0.028cm2, power density of 3.57W/cm2 was used. The laser was applied at pre-defined points in the interphalangeal and metacarpophalangeal joints, totaling 24 points, 2 times a week, for 4 weeks, totaling 8 sessions. The Pain Inventory (IBD) and Visual Analogue Scale (VAS) were used for the analysis of pain and for the WHOQOL-bref quality of life assessment. There was no statistical difference between the onset (5.67±2.66) and the final (4.67±3.78) of treatments (p=0.70). There was also no statistical difference between the beginning (5.67±2.66) and the final (4.67±3.78) of the treatments in the VAS analysis (p=0.68). The overall mean quality of life obtained by the questionnaire at the start of treatment was 42.3±7.6, while at the end of treatment it was 58.5±7.6 (p=0.01) and the domains of the questionnaire with significant differences were: psychological domain 42.9±6.8 and 66.7±12.9 (p=0.004), social domain 39.9±5.7 and 68.1±6.3 (p=0,0005) and environmental domain 36.3±7.3 and 56.3±12.5 (p=0.003). It can be concluded that the low-intensity therapeutic laser did not produce significant changes in the painful period of rheumatoid arthritis patients. However, there was an improvement in patients' quality of life in the psychological, social and environmental aspects.

Keywords: laser therapy, pain, quality of life, rheumatoid arthritis

Procedia PDF Downloads 246

Authors: V. Golubeva, O. Vakhnina, I. Konopkina, N. Gerasimova, N. Taturina, K. Zhogova

Abstract:

To improve chemical current sources, the ion-conducting electrolytes based on Li halides (LiCl-KCl, LiCl-LiBr-KBr, LiCl-LiBr-LiF) are developed. It is necessary to have chemical analytical methods for determination of halides to control the electrolytes technology. The methods of classical analytical chemistry are of interest, as they are characterized by high accuracy. Using these methods is a difficult task because halides have similar chemical properties. The objective of this work is to develop a titrimetric method for determining the content of bromides, chlorides, and fluorides in their joint presence in an ion-conducting electrolyte. In accordance with the developed method of analysis to determine fluorides, electrolyte sample is dissolved in diluted HCl acid; fluorides are titrated by La(NO₃)₃ solution with potentiometric indication of equivalence point, fluoride ion-selective electrode is used as sensor. Chlorides and bromides do not form a hardly soluble compound with La and do not interfere in result of analysis. To determine the bromides, the sample is dissolved in a diluted H₂SO₄ acid. The bromides are oxidized with a solution of KIO₃ to Br₂, which is removed from the reaction zone by boiling. Excess of KIO₃ is titrated by iodometric method. The content of bromides is calculated from the amount of KIO₃ spent on Br₂ oxidation. Chlorides and fluorides are not oxidized by KIO₃ and do not interfere in result of analysis. To determine the chlorides, the sample is dissolved in diluted HNO₃ acid and the total content of chlorides and bromides is determined by method of visual mercurometric titration with diphenylcarbazone indicator. Fluorides do not form a hardly soluble compound with mercury and do not interfere with determination. The content of chlorides is calculated taking into account the content of bromides in the sample of electrolyte. The validation of the developed analytical method was evaluated by analyzing internal reference material with known chlorides, bromides and fluorides content. The analytical method allows to determine chlorides, bromides and fluorides in case of their joint presence in ion-conducting electrolyte within the range and with relative total error (δ): for bromides from 60.0 to 65.0 %, δ = ± 2.1 %; for chlorides from 8.0 to 15.0 %, δ = ± 3.6 %; for fluorides from 5.0 to 8.0%, ± 1.5% . The analytical method allows to analyze electrolytes and mixtures that contain chlorides, bromides, fluorides of alkali metals and their mixtures (K, Na, Li).

Keywords: bromides, chlorides, fluorides, ion-conducting electrolyte

Procedia PDF Downloads 122

Authors: Manuela Amorim, Cláudia S. Marques, Maria Conceição Calhau, Hélder J. Pinheiro, Maria Manuela Pintado

Abstract:

Recently it has been recognized peptides from different food sources with biological activities. However, no relevant study has proven the potential of brewer yeast peptides in the modulation of gut microbiota. The importance of human intestinal microbiota in maintaining host health is well known. Probiotics, prebiotics and the combination of these two components, can contribute to support an adequate balance of the bacterial population in the human large intestine. The survival of many bacterial species inhabiting the large bowel depends essentially on the substrates made available to them, most of which come directly from the diet. Some of these substrates can be selectively considered as prebiotics, which are food ingredients that can stimulate beneficial bacteria such as Lactobacilli or Bifidobacteria growth in the colon. Moreover, conventional food can be used as vehicle to intake bioactive compounds that provide those health benefits and increase people well-being. In this way, the main objective of this work was to study the potential prebiotic activity of brewer yeast peptide extract (BYP) obtained via hydrolysis of yeast proteins by cardosins present in Cynara cardunculus extract for possible use as a functional ingredient. To evaluate the effect of BYP on the modulation of gut microbiota in diet-induced obesity model, Wistar rats were fed either with a standard or a high-fat diet. Quantified via 16S ribosomal RNA (rRNA) expression by quantitative PCR (qPCR), genera of beneficial bacteria (Lactobacillus spp. and Bifidobacterium spp.) and three main phyla (Firmicutes, Bacteroidetes and Actinobacteria) were assessed. Results showed relative abundance of Lactobacillus spp., Bifidobacterium spp. and Bacteroidetes was significantly increased (P < 0.05) by BYP. Consequently, the potential health-promoting effects of WPE through modulation of gut microbiota were demonstrated in vivo. Altogether, these findings highlight the possible intervention of BYP as gut microbiota enhancer, promoting healthy life style, and the incorporation in new food products, leads them bringing associated benefits endorsing a new trend in the improvement of new value-added food products.

Keywords: functional ingredients, gut microbiota, prebiotics, brewer yeast peptide extract

Procedia PDF Downloads 491

Authors: Opeyemi Awau Adepoju

Abstract:

The task of nation-building for Nigeria, like other developing nations, has continued to be riddled with audacious challenges that kept threatening to consume the state itself. Among the destabilizing factors that are sometimes mutually reinforcing are poverty and insecurity. Nigeria has been bedeviled with poverty since the onset of the 1980s when the country metamorphosed from an agricultural to an oil-based economy coupled with unbridled political corruption and wasteful management of resources by successive governments. The crippling poverty started manifesting in the scourge of criminalities and a general state of insecurity. Poverty gradually becomes the breeder of insecurity and threats to human life in Nigeria. Interestingly, successive governments tended to recognize the destructive tendencies of poverty and took several interventionist initiatives towards abating or slowing down the spate of poverty so as to reverse the trend of insecurity, but none of those initiatives can be adjudged good or enduring legacies. The emergence of the Buhari administration in 2015 provided a new opportunity to tackle poverty and, in turn, insecurity that had permeated every aspect of national life before that year’s presidential elections. Expectedly, the government took ambitious steps through its innovative ideas of intervention through its National Social Intervention Programmes (NSIP). Therefore, this paper is an assessment of the Buhari administration’s initiatives in poverty eradication in Nigeria as one of its strategies to fight insecurity, and the paper adopted a qualitative approach. The theoretical arguments put up by this paper are with respect to the connection between poverty and insecurity sourced from the theory of Relative Deprivation. The paper found that the Buhari administration has done better than any government since 1999 in inventing a social intervention program and that the poverty of the people has been addressed to a notable extent. However, the problem of politicization of intervention programs has continued to be the practice under the administration, and if this is not abated, the post-Buhari era may as well be like the eras before it. The paper recommends legislation that can make poverty ameliorating programs permanent, at least for some years to come, so as to avoid the usual policy summersault at every instance of political transition, which has limited the sustainability of public policies and indeed hindered nation-building efforts in Nigeria.

Keywords: insecurity, poverty alleviation, public policies, social intervention

Procedia PDF Downloads 50

Authors: Nirupama Sam

Abstract:

COVID-19, the greatest pandemic since the turn of the century, presents several issues for urban planners, the most significant of which is determining appropriate mitigation techniques for creating pandemic-friendly and resilient public spaces. The study is conducted in four stages. The first stage consisted of literature reviews to examine the evolution and transformation of public spaces during pandemics throughout history and the role of public spaces during pandemic outbreaks. The second stage is to determine the factors that influence the success of public spaces, which was accomplished by an analysis of current literature and case studies. The influencing factors are categorized under comfort and images, uses and activity, access and linkages, and sociability. The third stage is to establish the priority of identified factors for which a questionnaire survey of stakeholders is conducted and analyzing of certain factors with the help of GIS tools. COVID-19 has been in effect in India for the last two years. Kerala has the highest daily COVID-19 prevalence due to its high population density, making it more susceptible to viral outbreaks. Despite all preventive measures taken against COVID-19, Kerala remains the worst-affected state in the country. Finally, two live case studies of the hardest-hit localities, namely Subhash bose park and Napier Museum park in the Ernakulam and Trivandrum districts of Kerala, respectively, were chosen as study areas for the survey. The responses to the questionnaire were analyzed using SPSS for determining the weights of the influencing factors. The spatial success of the selected case studies was examined using the GIS interpolation model. Following the overall assessment, the fourth stage is to develop strategies and guidelines for planning public spaces to make them more efficient and robust, which further leads to improved quality, safety and resilience to future pandemics.

Keywords: urban design, public space, covid-19, post-pandemic, public spaces

Procedia PDF Downloads 129

Authors: Hongquan Zhang

Abstract:

Inspired by endogenous protein motors, researchers have constructed various synthetic DNA motors based on the specificity and predictability of Watson-Crick base pairing. However, the application of DNA motors to signal amplification and biosensing is limited because of low mobility and difficulty in real-time monitoring of the walking process. The objective of our work was to construct a new type of DNA motor termed target-triggered DNA motors that can walk for hundreds of steps in response to a single target binding event. To improve the mobility and processivity of DNA motors, we used gold nanoparticles (AuNPs) as scaffolds to build high-density, three-dimensional tracks. Hundreds of track strands are conjugated to a single AuNP. To enable DNA motors to respond to specific protein and nucleic acid targets, we adapted the binding-induced DNA assembly into the design of the target-triggered DNA motors. In response to the binding of specific target molecules, DNA motors are activated to autonomously walk along AuNP, which is powered by a nicking endonuclease or DNAzyme-catalyzed cleavage of track strands. Each moving step restores the fluorescence of a dye molecule, enabling monitoring of the operation of DNA motors in real time. The motors can translate a single binding event into the generation of hundreds of oligonucleotides from a single nanoparticle. The motors have been applied to amplify the detection of proteins and nucleic acids in test tubes and live cells. The motors were able to detect low pM concentrations of specific protein and nucleic acid targets in homogeneous solutions without the need for separation. Target-triggered DNA motors are significant for broadening applications of DNA motors to molecular sensing, cell imagining, molecular interaction monitoring, and controlled delivery and release of therapeutics.

Keywords: biosensing, DNA motors, gold nanoparticles, signal amplification

Procedia PDF Downloads 81

Authors: S. Alemayehu, F. A. Abera, K. M. Ayimut, R. Mahroof, J. Harvey, B. Subramanyam

Abstract:

The occurrence of mycotoxins in sesame seeds poses a significant threat to food safety and the economy in Ethiopia. This study aimed to determine the levels and occurrence of mycotoxins in on-farm stored sesame seeds in major-growing districts of Ethiopia. A total of 470 sesame seed samples were collected from randomly selected farmers' storage structures in five major-growing districts using purposive sampling techniques. An enzyme-linked immunosorbent assay (ELISA) was used to analyze the collected samples for the presence of four mycotoxins: total aflatoxins (AFT), ochratoxin A (OTA), total fumonisins (FUM), and deoxynivalenol (DON). The study found that all samples contained varying levels of mycotoxins, with AFT and DON being the most prevalent. AFT concentrations in detected samples ranged from 2.5 to 27.8 parts per billion (ppb), with a mean concentration of 13.8 ppb. OTA levels ranged from 5.0 ppb to 9.7 ppb, with a mean level of 7.1 ppb. Total fumonisin concentrations ranged from 300 to 1300 ppb in all samples, with a mean of 800 ppb. DON concentrations ranged from 560 to 700 ppb in the analyzed samples. The majority (96.8%) of the samples were safe from AFT, FUM, and DON mean levels when compared to the Federal Drug Administration maximum limit. AFT-OTA, DON-OTA, AFT-FUM, FUM-DON, and FUM-OTA, respectively, had co-occurrence rates of 44.0, 38.3, 33.8, 30.2, 29.8 and 26.0% for mycotoxins. On average, 37.2% of the sesame samples had fungal infection, and seed germination rates ranged from 66.8% to 91.1%. The Limmu district had higher levels of total aflatoxins, kernel infection, and lower germination rates than other districts. The Wollega variety of sesame had higher kernel infection, total aflatoxins concentration, and lower germination rates than other varieties. Grain age had a statistically significant (p<0.05) effect on both kernel infection and germination. The storage methods used for sesame in major-growing districts of Ethiopia favor mycotoxin-producing fungi. As the levels of mycotoxins in sesame are of public health significance, stakeholders should come together to identify secure and suitable storage technologies to maintain the quantity and quality of sesame at the level of smallholder farmers. This study suggests the need for suitable storage technologies to maintain the quality of sesame and reduce the risk of mycotoxin contamination.

Keywords: districts, seed germination, kernel infection, moisture content, relative humidity, temperature

Procedia PDF Downloads 125

Authors: Intisar, Khalifa, Salim, Al Busaidi

Abstract:

Recently, the synergic combination of low salinity water flooding with polymer flooding has been a subject of paramount interest for the oil industry. Numerous studies have investigated the efficiency of enhanced oil recovery using low salinity polymer flooding (LSPF). However, there is no clear conclusion that can explain the incremental oil recovery, determine the main factors controlling the oil recovery process, and define the relative contribution of rock/fluids or fluid/fluid interactions to extra oil recovery. Therefore, this study aims to perform a systematic investigation of the interactions between oil, polymer, low salinity and sandstone rock surface from pore to core scale during LSPF. Partially hydrolyzed polyacrylamide (HPAM) polymer, Boise outcrop, a crude oil sample and reservoir cores from an Omani oil field, and brine at two different salinities were used in the study. Several experimental measurements including static bulk measurements of polymer solutions prepared with brines of high and low salinities, single phase displacement experiments, along with rheological, total organic carbon and ion chromatography measurements to analyze ion exchange reactions, polymer adsorption, and viscosity loss were used. In addition, two-phase experiments were performed to demonstrate the oil recovery efficiency of LSPF. The results revealed that the incremental oil recovery from LSPF was attributed to the combination of the reduction in the water-oil mobility ratio, an increase in the repulsion forces between crude oil/brine/rock interfaces and an increase in pH of the aqueous solution. In addition, lowering the salinity of the make-up brine resulted in a larger conformation (expansion) of the polymer molecules, which in turn resulted in less adsorption and a greater in-situ viscosity without any negative impact on injectivity. This plays a positive role in the oil displacement process. Moreover, the loss of viscosity in the effluent of polymer solutions was lower in low-salinity than in high-salinity brine, indicating that an increase in cations concentration (mainly driven by Ca2+ ions) has stronger effect on the viscosity of high-salinity polymer solution compared with low-salinity polymer.

Keywords: polymer, heavy oil, low salinity, COBR interactions

Procedia PDF Downloads 87

Authors: Sharmin Ferdewsi Rakhi, A. H. M. Mohsinul Reza, Brynley Davies, Jianzhong Wang, Youhong Tang, Jian Qin

Abstract:

Mass production of microalgae has become a focus of research owing to their promising aspects for sustainable food, biofunctional compounds, and biofuel feedstock. However, low lipid content with optimum algal biomass is still a challenge that must be resolved for commercial use. This research aims to determine the effects of light spectral shift and reactive oxygen species (ROS) on growth and lipid biosynthesis in a green microalga, Chlamydomonas reinhardtii. Aggregation Induced Emission (AIE)-based photosensitisers, CN-TPAQ-PF6 ([C₃₂H₂₃N₄]+) with high ROS productivity, was introduced into the algal culture media separately for effective conversion of the green-yellow-light to the red spectra. The intense photon energy and high-photon flux density in the photosystems and ROS supplementation induced photosynthesis and lipid biogenesis. In comparison to the control, maximum algal growth (0.15 g/l) was achieved at 2 µM CN-TPAQ-PF6 exposure. A significant increase in total lipid accumulation (146.87 mg/g dry biomass) with high proportion of 10-Heptadecanoic acid (C17:1) linolenic acid (C18:2), α-linolenic acid (C18:3) was observed. The elevated level of cellular NADP/NADPH triggered the Acetyl-Co-A production in lipid biogenesis cascade. Furthermore, MTT analysis suggested that this nanomaterial is highly biocompatible on HaCat cell lines with 100% cell viability. This study reveals that the AIE-based approach can strongly impact algal biofactory development for sustainable food, healthy lipids and eco-friendly biofuel.

Keywords: microalgae, photosensitiser, lipid, biomass, aggregation-induced-emission, reactive oxygen species

Procedia PDF Downloads 45

Authors: María Teresa Baquero, Ester Higueras

Abstract:

One of the challenges facing 21st century cities, is their adaptation to the phenomenon of an ageing population. International policies have been developed, such as the "Global Network for Age-friendly Cities and Communities". These cities must recognize the diversity of the elderly population, and facilitate an active, healthy, satisfied aging and promote inclusion. In order to promote active and healthy aging, older people should be encouraged to engage in physical activity, sunbathe, socialize and enjoy the public open spaces in the city. Some studies recognize thermal comfort as one of the factors that most influence the use of public open spaces. However, although some studies have shown vulnerability to thermal extremes and environmental conditions in older people, there is little research on thermal comfort for older adults, because it is usually analyzed based on the characteristics of the ¨average young person¨ without considering the physiological, physical and psychological differences that characterize the elderly. This study analyzes the relationship between the microclimate parameters as air temperature, relative humidity, wind speed and sky view factor (SVF) with the personal thermal perception of older adults in three public spaces in Madrid, through a mixed methodology that combines weather measurements with interviews, made during the year 2018. Statistical test like Chi-square, Spearman, and analysis of variance were used to analyze the relationship between preference votes and thermal sensation votes with environmental and personal parameters. The results show that there is a significant correlation between thermal sensation and thermal preference with the measured air temperature, age, level of clothing, the color of clothing, season, time of the day and kind of space while no influence of gender or other environmental variables was detected. These data would contribute to the design of comfortable public spaces that improve the welfare of the elderly contributing to "active and healthy aging" as one of the 21st century challenges cities face.

Keywords: healthy ageing, older adults, outdoor public space, thermal perception

Procedia PDF Downloads 129

Authors: Arun Kumar Yadav

Abstract:

Coal contributes a significant role in India’s developmental mission. But, ironically, on the other side it causes large scale population displacement and significant changes in indigenous people’s livelihood mechanism. Dhanbad which is regarded as one of the oldest and large mining area, as well as a “Coal Capital of India”. Here, mining exploration work started nearly a century ago. But with the passage of time, mining brings a lot of changes in the life of local people. In this context, study tries to do comparative situational analysis of the changes in the living condition of dwellers living in mines affected and non-mines affected villages based on livelihood approach. Since, this place has long history of mining so it is very difficult to conduct before and after comparison between mines and non-mines affected areas. Consequently, the present study is based on relative comparison approach to elucidate the actual scenario. By using primary survey data which was collected by the author during the month of September 2014 to March 2015 at Dhanbad, Jharkhand. The data were collected from eight villages, these were categorised broadly into mines and non-mines affected villages. Further at micro level, mines affected villages has been categorised into open cast and underground mines. This categorization will help us to capture the deeper understanding about the issues of mine affected villages group. Total of 400 household were surveyed. Result depicts that in every sphere mining affected villages are more vulnerable. Regarding financial capital, although mine affected villages are engaged in mining work and get higher mean income. But in contrast, non-mine affected villages are more occupationally diversified. They have an opportunity to earn money from diversified extents like agricultural land, working in mining area, selling coal informally as well as receiving remittances. Non-mines affected villages are in better physical capital which comprises of basic infrastructure to support livelihood. They have an access to secured shelter, adequate water supply & sanitation, and affordable information and transport. Mining affected villages are more prone to health risks. Regarding social capital, it shows that in comparison to last five years, law and order has been improved in mine affected villages.

Keywords: displacement, indigenous, livelihood, mining

Procedia PDF Downloads 305

Authors: Pouneh Soleimaninejadian, Chengyu Yang

Abstract:

In this paper, we use data on Household Income and Expenditure survey of Statistics Centre of Iran, conducted from 2005-2014, to calculate several inequality measures and to estimate the effects of Iran’s targeted subsidy reform act on consumption and income inequality. We first calculate Gini coefficients for income and consumption in order to study the relation between the two and also the effects of subsidy reform. Results show that consumption inequality has not been always mirroring changes in income inequality. However, both Gini coefficients indicate that subsidy reform caused improvement in inequality. Then we calculate Generalized Entropy Index based on consumption and income for years before and after the Subsidy Reform Act of 2010 in order to have a closer look into the changes in internal structure of inequality after subsidy reforms. We find that the improvement in income inequality is mostly caused by the decrease in inequality of lower income individuals. At the same time consumption inequality has been decreased as a result of more equal consumption in both lower and higher income groups. Moreover, the increase in Engle coefficient after the subsidy reform shows that a bigger portion of income is allocated to consumption on food which is a sign of lower living standard in general. This increase in Engle coefficient is due to rise in inflation rate and relative increase in price of food which partially is another consequence of subsidy reform. We have conducted some experiments on effect of subsidy payments and possible effects of change on distribution pattern and amount of cash subsidy payments on income inequality. Result of the effect of cash payments on income inequality shows that it leads to a definite decrease in income inequality and had a bigger share in improvement of rural areas compared to those of urban households. We also examine the possible effect of constant payments on the increasing income inequality for years after 2011. We conclude that reduction in value of payments as a result of inflation plays an important role regardless of the fact that there may be other reasons. We finally experiment with alternative allocations of transfers while keeping the total amount of cash transfers constant or make it smaller through eliminating three higher deciles from the cash payment program, the result shows that income equality would be improved significantly.

Keywords: consumption inequality, generalized entropy index, income inequality, Irans subsidy reform

Procedia PDF Downloads 229

Authors: I. Diamant, R. Srouji

Abstract:

Applicant perceptions are attitudes, feelings, and cognitions which individuals have about selection procedures and have been mostly studied in the context of personnel selection. The main aim of the present study is to expand the understanding of applicant perceptions, using the framework of Organizational Justice Theory, in the domain of selection for higher education. The secondary aim is to explore the relationships between individual differences in social anxiety and applicants’ perceptions. The selection process is an accept/reject situation; it was hypothesized that applicants with higher social anxiety would experience negative perceptions and a lower success estimation, especially when subjected to social interaction elements in the process (interview and group simulation). Also, the effects of prior preparation and post-process explanations offered at the end of the selection process were explored. One hundred sixty psychology M.A. program applicants participated in this research, and following the selection process completed questionnaires measuring social anxiety, social exclusion, ratings on several justice dimensions for each of the methods in the selection process, feelings of success, and self-estimation of compatibility. About half of the applicants also received explanations regarding the significance and the aims of the selection process. Results provided support for most of our hypotheses: applicants with higher social anxiety experienced an increased level of social exclusion in the selection process, perceived the selection as less fair and ended with a lower feeling of success relative to those applicants without social anxiety. These relationships were especially salient in the selection procedures which included social interaction. Additionally, preparation for the selection process was positively related to the favorable perception of fairness in the selection process. Finally, contrary to our hypothesis, it was found that explanations did not affect the applicant’s perceptions. The results enhance our understanding of which factors affect applicant perceptions in applicants to higher education studies and contribute uniquely to the understanding of the effect of social anxiety on different aspects of selection experienced by applicants. The findings clearly show that some individuals may be predisposed to react unfavorably to certain selection situations. In an age of increasing awareness towards fairness in evaluation and selection and hiring procedures, these findings may be of relevance and may contribute to the design of future personnel selection methods in general and of higher education selection in particular.

Keywords: applicant perceptions, selection and assessment, organizational justice theory, social anxiety

Procedia PDF Downloads 145

Authors: Henry Navarro, Martin Sirena, Nestor Haberkorn

Abstract:

We report the electrical transport through voltage-current curves (I-V) in tunnels junction GdBa₂Cu₃O₇-d/ insulator/ GdBa₂Cu₃O₇-d, and Nb/insulator/ GdBa₂Cu₃O₇-d is analyzed using a conducting atomic force microscope (CAFM) at room temperature. The measurements were obtained on tunnel junctions with different areas (900 μm², 400 μm² and 100 μm²). Trilayers with GdBa₂Cu₃O₇-d (GBCO) as the bottom electrode, SrTiO₃ (STO) or BaTiO₃ (BTO) as the insulator barrier (thicknesses between 1.6 nm and 4 nm), and GBCO or Nb as the top electrode were grown by DC sputtering on (100) SrTiO₃ substrates. For STO and BTO barriers, asymmetric IV curves at positive and negative polarization can be obtained using electrodes with different work function. The main difference is that the BTO is a ferroelectric material, while in the STO the ferroelectricity can be produced by stress or deformation at the interfaces. In addition, hysteretic IV curves are obtained for BTO barriers, which can be ascribed to a combined effect of the FE reversal switching polarization and an oxygen vacancy migration. For GBCO/ BTO/ GBCO heterostructures, the IV curves correspond to that expected for asymmetric interfaces, which indicates that the disorder affects differently the properties at the bottom and top interfaces. Our results show the role of the interface disorder on the electrical transport of conducting/ insulator/ conduction heterostructures, which is relevant for different applications, going from resistive switching memories (at room temperature) to Josephson junctions (at low temperatures). The superconducting transition of the GBCO electrode was characterized by electrical transport using the 4-prong configuration with low density of topological defects and with Tc over liquid N₂ can be obtained for thicknesses of 16 nm, our results demonstrate that GBCO films with an average root-mean-square (RMS) smaller than 1 nm and areas (up 100 um²) free of 3-D topological defects can be obtained.

Keywords: thin film, sputtering, conductive atomic force microscopy, tunnel junctions

Procedia PDF Downloads 150

Authors: Chahrazed Zouaoui

Abstract:

In recent years, the volume of geospatial information is increasing due to the evolution of communication technologies and information, this information is presented often by geographic information systems (GIS) and stored on of spatial databases (BDS). The classical data mining revealed a weakness in knowledge extraction at these enormous amounts of data due to the particularity of these spatial entities, which are characterized by the interdependence between them (1st law of geography). This gave rise to spatial data mining. Spatial data mining is a process of analyzing geographic data, which allows the extraction of knowledge and spatial relationships from geospatial data, including methods of this process we distinguish the monothematic and thematic, geo- Clustering is one of the main tasks of spatial data mining, which is registered in the part of the monothematic method. It includes geo-spatial entities similar in the same class and it affects more dissimilar to the different classes. In other words, maximize intra-class similarity and minimize inter similarity classes. Taking account of the particularity of geo-spatial data. Two approaches to geo-clustering exist, the dynamic processing of data involves applying algorithms designed for the direct treatment of spatial data, and the approach based on the spatial data pre-processing, which consists of applying clustering algorithms classic pre-processed data (by integration of spatial relationships). This approach (based on pre-treatment) is quite complex in different cases, so the search for approximate solutions involves the use of approximation algorithms, including the algorithms we are interested in dedicated approaches (clustering methods for partitioning and methods for density) and approaching bees (biomimetic approach), our study is proposed to design very significant to this problem, using different algorithms for automatically detecting geo-spatial neighborhood in order to implement the method of geo- clustering by pre-treatment, and the application of the bees algorithm to this problem for the first time in the field of geo-spatial.

Keywords: mining, GIS, geo-clustering, neighborhood

Procedia PDF Downloads 370

Authors: Kamil Dydek, Anna Boczkowska, Paulina Latko-Duralek, Rafal Kozera, Michal Salacinski

Abstract:

In recent years there has been increasing interest in many industries, such as the aviation, automotive, and military industries, in Carbon Fibre Reinforced Polymers (CFRP). This is because of the excellent properties of CFRP, which are characterized by very high strength and stiffness in relation to their mass, low density (almost twice as low as aluminum and more than five times as low as steel), and corrosion resistance. However, they do not have sufficient electrical conductivity, which is required in some applications. Therefore, work is underway to improve their electrical conductivity, for example, by incorporating carbon nanotubes (CNTs) into the CFRP structure. CNTs possess excellent properties, such as high electrical conductivity, high aspect ratio, high Young’s modulus, and high tensile strength. An idea developed by our team is a modification of CFRP by the use of thermoplastic nonwovens containing CNTs. Nanocomposite fibers were made from three different masterbatches differing in the content of multi-wall carbon nanotubes, and then nonwovens that differed in areal weight were produced using a thermo-press. The out of autoclave method was used to fabricate the laminates from commercial carbon-epoxy prepreg dedicated to aviation applications - one without the nonwovens (reference) and five containing nonwovens placed between each prepreg layer. The volume of electrical conductivity of the manufactured laminates was measured in three directions. In order to investigate the adhesion between carbon fibers and nonwovens, the microstructure of the produced laminates was observed. The mechanical properties of the CFRP composites were measured in a short-beam shear test. In addition, the influence of thermoplastic nonwovens on the thermos-mechanical properties of laminates was analyzed by Dynamic Mechanical Analysis. The studies were carried out within grant no. DOB-1-3/1/PS/2014 financed by the National Centre for Research and Development in Poland.

Keywords: CFRP, thermoplastic nonwovens, carbon nanotubes, electrical conductivity

Procedia PDF Downloads 129

Authors: Adedolapo Ayoade, John the Beloved Dada

Abstract:

This study identified the phytoplankton assemblage of the Dandaru Lake (that received effluents from a zoological garden and hospital) as bioindicators of water quality. Physicochemical parameters including Dissolved Oxygen (DO), biochemical oxygen demand, nitrate, phosphate and heavy metals were also determined. Samples of water and plankton were collected once monthly from April to September, 2015 at five stations (I – V). The mean physicochemical parameters were within the limits of National Environmental Standards and Regulations Enforcement Agency (NESREA) and USEPA except Lead, 0.02 ± 0.08 mg/ L; Manganese, 0.46 ± 1.00 mg/ L and Zinc, 0.05 ± 0.17 mg/ L. Means of DO, alkalinity, and phosphate were significantly different between the stations at p < 0.05. While highest mean DO (6.88 ± 1.34 mg/L) was recorded in station I with less anthropogenic activities, highest phosphate concentration (0.28 ± 0.28 mg/L) occurred in station II, the entry point of wastewater from hospital and zoological garden. The 147 phytoplankton species found in the lake belonged to six classes: Chlorophyceae (50), Euglenophyceae (40), Bacillariophyceae (37), Cyanophyceae (17), Xanthophyceae and Chrysophyceae (3). The order of abundance for phytoplankton was Euglenophyceae (49.77%) > Bacillariophyceae (18.00%) > Cyanophyceae (17.39%) > Chlorophyceae (13.7%) > Xanthophyceae (1.06%) > Chrysophyceae (0.02%). The stations impacted with effluents were dominated by members of Euglenophyceae (Station III, 77.09%; IV, 50.55%) and Cyanophyceae (Station II, 27.7%; V, 32.57%). While station I was dominated by diatoms (57.98%). The species richness recorded was 0.32 – 4.49. Evenness index was highest in station I and least in station III. Generally, pollution tolerant species (Microcystis, Oscillatoria, Scenedesmus, Anabaena, and Euglena) showed greater density in areas impacted by human activities. The phytoplankton assemblage and comparatively low biotic diversity in Dandaru Lake could be attributed to perturbations in the water column that exerted selective effects on the biological assemblage.

Keywords: manmade lake, Nigeria, phytoplankton, water quality

Procedia PDF Downloads 253

Authors: Olatunde Sunday Eludoyin, Charles Obiechina Olisa

Abstract:

The study examined the spatial interactions between earthworm abundance (EA) and tree growth characteristics in ecological belts of Western Niger Delta, Nigeria. Eight 20m x 20m quadrat were delimited in the natural vegetation in each of the rainforest (RF), mangrove (M), fresh water swamp (FWS), and guinea savanna (GS) ecological belts to gather data about the tree species (TS) characteristics which included individual number of tree species (IN), diversity (Di), density (De) and richness (Ri). Three quadrats of 1m x 1m were delineated in each of the 20m x 20m quadrats to collect earthworm species the topsoil (0-15cm), and subsoil (15-30cm) and were taken to laboratory for further analysis. Descriptive statistics and inferential statistics were used for data analysis. Findings showed that a total of 19 earthworm species was found, with 58.5% individual species recorded in the topsoil and 41.5% recorded in the subsoil. The total population ofEudriliuseugeniae was predominantly highest in both topsoil (38.4%) and subsoil (27.1%). The total population of individual species of earthworm was least in GS in the topsoil (11.9%) and subsoil (8.4%). A total of 40 different species of TS was recorded, of which 55.5% were recorded in FWS, while RF was significantly highest in the species diversity(0.5971). Regression analysis revealed that Ri, IN, DBH, Di, and De of trees explained 65.9% of the variability of EA in the topsoil, while 46.9 % of the variability of earthworm abundance was explained by the floristic parameters in the subsoil.Similarly, correlation statistics revealed that in the topsoil, EA is positively and significantly correlated with Ri (r=0.35; p<0.05), IN (r=0.523; p<0.05) and De (r=0.469; p<0.05) while DBH was negatively and significantly correlated with earthworm abundance (r=-0.437; p<0.05). In the subsoil, only Ri and DBH correlated significantly with EA. The study concluded that EA in the study locations was highly influenced by tree growth species especially Ri, IN, DBH, Di, and De. The study recommended that the TSabundance should be improved in the study locations to ensure the survival of earthworms for ecosystem functions.

Keywords: interactions, earthworm abundance, tree growth, ecological zones, western niger delta

Procedia PDF Downloads 95

Authors: Arun Kumar Singh, Rupesh M. Das, Shailendra Saini

Abstract:

The present work is an attempt to evaluate the sub-auroral ionospheric behavior under changing space weather conditions especially during high solar activity year 2014. In view of this, the GPS TEC along with Ionosonde data over Indian permanent scientific base 'Maitri', Antarctica (70°46′00″ S, 11°43′56″ E) has been utilized. The results suggested that the nature of ionospheric responses to the geomagnetic disturbances mainly depended upon the status of high latitudinal electro-dynamic processes along with the season of occurrence. Fortunately, in this study, both negative and positive ionospheric impact to the geomagnetic disturbances has been observed in a single year but in different seasons. The study reveals that the combination of equator-ward plasma transportation along with ionospheric compositional changes causes a negative ionospheric impact during summer and equinox seasons. However, the combination of pole-ward contraction of the oval region along with particle precipitation may lead to exhibiting positive ionospheric response during the winter season. Other than this, some Ionosonde based new experimental evidence also provided clear evidence of particle precipitation deep up to the low altitudinal ionospheric heights, i.e., up to E-layer by the sudden and strong appearance of E-layer at 100 km altitudes. The sudden appearance of E-layer along with a decrease in F-layer electron density suggested the dominance of NO⁺ over O⁺ at a considered region under geomagnetic disturbed condition. The strengthening of E-layer is responsible for modification of auroral electrojet and field-aligned current system. The present study provided a good scientific insight on sub-auroral ionospheric to the changing space weather condition.

Keywords: high latitude ionosphere, space weather, geomagnetic storms, sub-storm

Procedia PDF Downloads 161

Authors: Ola Elfmark, Lars M. Bardal, Luca Oggiano, H˚avard Myklebust

Abstract:

Team pursuit is a relatively new event in international long track speed skating. For a single speed skater the aerodynamic drag will account for up to 80% of the braking force, thus reducing the drag can greatly improve the performance. In a team pursuit the interactions between athletes in near proximity will also be essential, but is not well studied. In this study, systematic measurements of the aerodynamic drag, body posture and relative positioning of speed skaters have been performed in the low speed wind tunnel at the Norwegian University of Science and Technology, in order to investigate the aerodynamic interaction between two speed skaters. Drag measurements of static speed skaters drafting, leading, side-by-side, and dynamic drag measurements in a synchronized and unsynchronized movement at different distances, were performed. The projected frontal area was measured for all postures and movements and a blockage correction was performed, as the blockage ratio ranged from 5-15% in the different setups. The static drag measurements where performed on two test subjects in two different postures, a low posture and a high posture, and two different distances between the test subjects 1.5T and 3T where T being the length of the torso (T=0.63m). A drag reduction was observed for all distances and configurations, from 39% to 11.4%, for the drafting test subject. The drag of the leading test subject was only influenced at -1.5T, with the biggest drag reduction of 5.6%. An increase in drag was seen for all side-by-side measurements, the biggest increase was observed to be 25.7%, at the closest distance between the test subjects, and the lowest at 2.7% with ∼ 0.7 m between the test subjects. A clear aerodynamic interaction between the test subjects and their postures was observed for most measurements during static measurements, with results corresponding well to recent studies. For the dynamic measurements, the leading test subject had a drag reduction of 3% even at -3T. The drafting showed a drag reduction of 15% when being in a synchronized (sync) motion with the leading test subject at 4.5T. The maximal drag reduction for both the leading and the drafting test subject were observed when being as close as possible in sync, with a drag reduction of 8.5% and 25.7% respectively. This study emphasize the importance of keeping a synchronized movement by showing that the maximal gain for the leading and drafting dropped to 3.2% and 3.3% respectively when the skaters are in opposite phase. Individual differences in technique also appear to influence the drag of the other test subject.

Keywords: aerodynamic interaction, drag force, frontal area, speed skating

Procedia PDF Downloads 126

Authors: Joshua Chima Chizoba, Wisdom Izuchukwu Uzoma, Elizabeth Ifeyiwa Okoyeh

Abstract:

Water cannot be optimally used and sustained unless the quality is periodically assessed. The study area Umunneochi and environs are located in south eastern part of Nigeria. It stretches geographically from latitudes 50501N to 60000N and longitudes 70201E to 70301. The major geologic formations in the area include the Asu River group, Nkporo Shale, and Ajali Sandstone. The aim of this study is to evaluate the hydrochemical characteristics of surface and ground water sources in parts of Umunneochi and environs in order to establish portability of the water sources for drinking, domestic and irrigation purposes. A total of 15 samples were collected randomly from streams, springs and wells. The samples were analyzed for physicochemical parameters and heavy metals using handheld digital kits, photometer, titration method and Atomic Absorption Spectrophotometer (AAS) following acceptable standards. The obtained analytical data were interpreted, and results were compared with World Health Organization (WHO) standard. The concentration of pH, SO42-and Cl- range from 5.81 mg/l – 6.07 mg/l, 41.93 mg/l – 142.95 mg/l and 20.00 mg/l – 111 mg/l respectively, while Pb and Zn revealed a relative low mean concentration of 0.14 mg/l and 0.40 mg/l, which are all within (WHO) permissible limits except pH. About 27% of the samples are moderately hard. This is attributed to the mining activities in the areas. The abundance of cations and anions in the area are in the order of K+>Na+>Mg2+>Ca2+ and SO4->Cl->HCO3->NO3-, respectively. Chloride, bicarbonate, and nitrate are all within the permissible limits. 13.33% of the total samples contain Sulphate above the standard permissible limits. The values of calculated Water Quality Index (WQI) are less than 50 indicating excellent water. The predominant water-type in the study area is Na-Cl water type and mixed Ca-Mg-Cl water type based on the sample plots on the Piper diagram. The Sodium Absorption Ratio (SAR) calculations showed excellent water for consumption and also good water for irrigation purpose with low sodium and alkalinity ratio respectively. Government water projects are recommended in the area for sustainable domestic and agricultural water supply to ease the stress of water supply problems.

Keywords: groundwater, hydrochemical, physichochemical, water-type, sodium adsorption ratio

Procedia PDF Downloads 129

Authors: Amiya Kumar Pati, Spandan Sahu, Kishanjit Kumar Khatua

Abstract:

River is our main source of water which is a form of open channel flow and the flow in the open channel provides with many complex phenomena of sciences that needs to be tackled such as the critical flow conditions, boundary shear stress, and depth-averaged velocity. The development of society, more or less solely depends upon the flow of rivers. The rivers are major sources of many sediments and specific ingredients which are much essential for human beings. A river flow consisting of small and shallow channels sometimes divide and recombine numerous times because of the slow water flow or the built up sediments. The pattern formed during this process resembles the strands of a braid. Braided streams form where the sediment load is so heavy that some of the sediments are deposited as shifting islands. Braided rivers often exist near the mountainous regions and typically carry coarse-grained and heterogeneous sediments down a fairly steep gradient. In this paper, the apparent shear stress formulae were suitably modified, and the Energy Concept Method (ECM) was applied for the prediction of discharges at the junction of a two-flow braided compound channel. The Energy Concept Method has not been applied for estimating the discharges in the braided channels. The energy loss in the channels is analyzed based on mechanical analysis. The cross-section of channel is divided into two sub-areas, namely the main-channel below the bank-full level and region above the bank-full level for estimating the total discharge. The experimental data are compared with a wide range of theoretical data available in the published literature to verify this model. The accuracy of this approach is also compared with Divided Channel Method (DCM). From error analysis of this method, it is observed that the relative error is less for the data-sets having smooth floodplains when compared to rough floodplains. Comparisons with other models indicate that the present method has reasonable accuracy for engineering purposes.

Keywords: critical flow, energy concept, open channel flow, sediment, two-flow braided compound channel

Procedia PDF Downloads 123