Search results for: normalized compression distance

Authors: D. Kumar, S. Kumar, A. G. Memon, R. A. Memon, K. Harijan

Abstract:

A considerable amount of energy is usually lost due to compression of insulation in Heating, ventilation, and air conditioning (HVAC) duct. In this paper, the economic impact of compression of insulation is estimated. Relevant mathematical models were used to estimate the optimal thickness at the points of compression. Furthermore, the payback period is calculated for the optimal thickness at the critical parts of supply air duct (SAD) and return air duct (RAD) considering natural gas (NG) and liquefied petroleum gas (LPG) as fuels for chillier operation. The mathematical model is developed using preliminary data obtained for an HVAC system of a pharmaceutical company. The higher heat gain and cooling loss, due to compression of thermal insulation, is estimated using relevant heat transfer equations. The results reveal that maximum energy savings (ES) in SAD is 34.5 and 40%, while in RAD is 22.9% and 29% for NG and LPG, respectively. Moreover, the minimum payback period (PP) for SAD is 2 and 1.6years, while in RAD is 4.3 and 2.7years for NG and LPG, respectively. The optimum insulation thickness (OIT) corresponding to maximum ES and minimum PP is estimated to be 35 and 42mm for SAD, while 30 and 38mm for RAD in case of NG and LPG, respectively.

Keywords: optimum insulation thickness, life cycle cost analysis, payback period, HVAC system

Procedia PDF Downloads 216

Authors: Daniel Ecler

Abstract:

This paper aims to compare the data obtained using semi-structured questionnaires and find some connections between them, which could help to understand what factors affect the perception of the advantages and disadvantages of distance learning compared to conventional education. The data collected came from respondents from Czech and Chinese university students, and expectations were such that the different cultural environments from which the two groups come would have an impact on different experiences of distance education. With the help of variation-finding comparison, it turned out that Chinese students did not have such difficulties with the transition to distance learning as students from the Czech Republic, as most of them came into contact with some form of distance education in the past. In addition, it has also been shown that Chinese students use modern technology to a much greater extent, which has also made it easier for them to become accustomed to another form of teaching. In conclusion, Chinese students have greater preconditions for easier management of distance learning, while Czech students prefer more personal contact, and thus full-time teaching. It is obvious that both approaches have their pros and cons; now, it is necessary to find out how to use them for maximum efficiency of the educational process.

Keywords: Chinese college students, cultural background, Czech college students, distance learning, full-time teaching

Procedia PDF Downloads 153

Authors: Hammam Aljabri, Hong G. Im

Abstract:

Hydrogen is a promising future fuel to support the transition of the energy sector toward carbon neutrality. The direct utilization of H2 in Internal Combustion Engines (ICEs) is possible, and this technology faces mainly two challenges; high NOx emissions and severe knocking at mid to high loads. In this study, we numerically investigated the potential of H2 combustion in a truck-size engine operated in SI mode. To mitigate the knocking nature of H2 combustion, we have focused on studying the effects of three primary parameters; the compression ratio (CR), the air-fuel ratio, and the spark time. The baseline case was set using a CR of 16.5 and an equivalence ratio of 0.35. In simulations, the auto-ignition tendency was evaluated based on the maximum pressure rise rate and the local pressure fluctuations at the monitoring points set along the wall of the combustion chamber. To mitigate the auto-ignition tendency while enabling a wider range of engine operation, the effect of lowering the compression ratio was assessed. The results indicate that by lowering the compression ratio from 16.5:1 to 12.5:1, an indicated thermal efficiency of 47.5% can be achieved. Aiming to restrain the auto-ignition while maintaining good efficiency, a reduction in the equivalence ratio was examined under different compression ratios. The result indicates that higher compression ratios will require lower equivalence ratios, and due to practical limitations, a lower equivalence ratio of 0.25 was set as the limit. Using a compression ratio of 13.5 combined with an equivalence ratio of 0.3 resulted in an indicated thermal efficiency of 48.6%, that is, at a fixed spark time. It is found that under such lean conditions, the incomplete combustion losses and exhaust losses were high. Thus, advancing the spark time was assessed as a possible solution. The results demonstrated the advantages of advancing the spark time, where an indicated thermal efficiency exceeding 50% was achieved using a compression ratio of 14.5:1 and an equivalence ratio of 0.25.

Keywords: hydrogen, combustion, engine knock, SI engine

Procedia PDF Downloads 130

Authors: Abbas Shafiee, Mohammad Taghi Ahmadian, Maryam Hoviattalab

Abstract:

The biomechanical behavior of brain tissue is needed for predicting the traumatic brain injury (TBI). Each year over 1.5 million people sustain a TBI in the USA. The appropriate coefficients for injury prediction can be evaluated using experimental data. In this study, an experimental setup on brain soft tissue was developed to perform unconfined compression tests at quasistatic strain rates ∈0.0004 s-1 and 0.008 s-1 and 0.4 stress relaxation test under unconfined uniaxial compression with ∈ 0.67 s-1 ramp rate. The fitted visco-hyperelastic parameters were utilized by using obtained stress-strain curves. The experimental data was validated using finite element analysis (FEA) and previous findings. Also, influence of friction coefficient on unconfined compression and relaxation test and effect of ramp rate in relaxation test is investigated. Results of the findings are implemented on the analysis of a human brain under high acceleration due to impact.

Keywords: brain soft tissue, visco-hyperelastic, finite element analysis (FEA), friction, quasistatic strain rate

Procedia PDF Downloads 656

Authors: Mahdi Pirmoradian, Olayinka Adigun, Christos Politis

Abstract:

Cooperative spectrum sensing is a crucial challenge in cognitive radio networks. Cooperative sensing can increase the reliability of spectrum hole detection, optimize sensing time and reduce delay in cooperative networks. In this paper, an efficient central capacity optimization algorithm is proposed to minimize cooperative sensing time in a homogenous sensor network using OR decision rule subject to the detection and false alarm probabilities constraints. The evaluation results reveal significant improvement in the sensing time and normalized capacity of the cognitive sensors.

Keywords: cooperative networks, normalized capacity, sensing time

Procedia PDF Downloads 636

Authors: Muhammad Afzal Malik

Abstract:

Traditional Learning & Distance based learning are the two systems prevailing in Pakistan. These systems affect the level of education standard. The purpose of this study was to compare the traditional classroom learning and distance learning in Pakistan: (a) To explore the effectiveness of the traditional to Distance learning in Pakistan; (b) To identify the factors that affect traditional and distance learning. This review found that, on average, students in traditional classroom conditions performed better than those receiving education in and distance learning. The difference between student outcomes for traditional Classroom and distance learning classes —measured as the difference between treatment and control means, divided by the pooled standard deviation— was larger in those studies contrasting conditions that blended elements of online and face-to-face instruction with conditions taught entirely face-to-face. This research was conducted to highlight the impact of distance learning education system on education standard. The education standards were institutional support, course development, learning process, student support, faculty support, evaluation and assessment. A well developed questionnaire was administered and distributed among 26 faculty members of GCET, H-9 and Virtual University of Pakistan from each. Data was analyzed through correlation and regression analysis. Results confirmed that there is a significant relationship and impact of DLE system on education standards. This will also provide baseline for future research. It will add value to the existing body of knowledge.

Keywords: distance learning education, higher education, education standards, student performance

Procedia PDF Downloads 280

Authors: E. Bittar, A. Quiñonez, F. Mencia, E. Aguero, M. Delgado, V. Arriola, R. López

Abstract:

In the western region of Paraguay, the poor condition of the roads has negatively affected the development of this zone, where the absence of petrous material has led engineers to opt for the stabilization of soils with lime or cement as the main structure for bases and subbases of these roads. In several areas of this region, high sulfate contents have been found both in groundwater and in soils, which, when reacted with lime or cement, generate a new problem instead of solving it. On the other hand, the use of industrial waste as granulated slag and fly ash proved to be a sustainable practice widely used in the manufacture of cement, and now also, in the stabilization of soils worldwide. Works related to soils containing sulfates stabilized either with granulated slag or fly ash and lime shown a good performance in their mechanical behaviour. This research seeks to evaluate the mechanical behaviour of soils with high contents of sulfates stabilized with lime by curing them both, at the normalized temperature (23 ± 2 °C) and at 40 ± 2 °C. Moreover, it attempts to asses if the addition of rice husk ash has a positive influence on the new geomaterial. The 40 ± 2 °C curing temperature was selected trying to simulate the average local temperature in summer and part of spring session whereas rice husk ash is an affordable waste produced in the region. An extensive experimental work, which includes unconfined compression, durability and free swell tests were carried out considering different dry unit weights, lime content and the addition of 20% of rice husk ash. The results showed that the addition of rice husk ash increases the resistance and durability of the material and decreases the expansion of this, moreover, the specimens cured at a temperature of 40 ± 2 °C showed higher resistance, better durability and lower expansion compared to those cured at the normalized temperature of 23 ± 2 °C.

Keywords: durability, expansion, lime stabilization, rice husk ash, sulfate

Procedia PDF Downloads 123

Authors: P. M. Keshtiban, M. Zadshakoyan

Abstract:

One of the important factors that alter different process and geometrical parameters on metal forming processes is friction between contacting surfaces. Some important factors that effected directly by friction are: stress, strain, required load, wear of surfaces and then geometrical parameters. In order to control friction effects permanent lubrication is necessary. In this article, the friction coefficient is elicited by the most effective method, ring compression tests. The tests were done by both finite element method and practical tests. Different friction curves that extracted by finite element simulations and has good conformity with published results, used for obtaining final friction coefficient. In this study Mos2 is used as the lubricant and Al5754 alloy used as the specimens material.

Keywords: experiment, FEM, friction coefficient, ring compression

Procedia PDF Downloads 463

Authors: Jamal Laaouine, Mohammed Elhassani Charkani

Abstract:

Let p be a prime and let b be an integer. MDS b-symbol codes are a direct generalization of MDS codes. The γ-constacyclic codes of length pˢ over the finite commutative chain ring Fₚm [u]/ < u² > had been classified into four distinct types, where is a nonzero element of the field Fₚm. Let C₃ be a code of Type 3. In this paper, we obtain the b-symbol distance db(C₃) of the code C₃. Using this result, necessary and sufficient conditions under which C₃ is an MDS b-symbol code are given.

Keywords: constacyclic code, repeated-root code, maximum distance separable, MDS codes, b-symbol distance, finite chain rings

Procedia PDF Downloads 139

Authors: Hyun Chang Kim, Yong Hun Jung, Kyung Woon Jeung

Abstract:

Background: From the viewpoint of cardiac pump theory, the area of the left ventricle (LV) subjected to compression increases as the LV lies closer to the sternum, possibly resulting in higher blood flow in patients with LV closer to the sternum. However, no study has evaluated LV position during cardiac arrest or its relationship with hemodynamic parameters during cardiopulmonary resuscitation (CPR). The objectives of this study were to determine whether the position of the LV relative to the anterior-posterior axis representing the direction of chest compression shifts during cardiac arrest and to examine the relationship between LV position and hemodynamic parameters during CPR. Methods: Subcostal view echocardiograms were obtained from 15 pigs with the transducer parallel to the long axis of the sternum before inducing ventricular fibrillation (VF) and during cardiac arrest. Computed tomography was performed in three pigs to objectively observe LV position during cardiac arrest. LV position parameters including the shortest distance between the anterior-posterior axis and the mid-point of the LV chamber (DAP-MidLV), the shortest distance between the anterior-posterior axis and the LV apex (DAP-Apex), and the area fraction of the LV located on the right side of the anterior-posterior axis (LVARight/LVATotal) were measured. Results: DAP-MidLV, DAP-Apex, and LVARight/LVATotal decreased progressively during untreated VF and basic life support (BLS), and then increased during advanced cardiovascular life support (ACLS). A repeated measures analysis of variance revealed significant time effects for these parameters. During BLS, the end-tidal carbon dioxide and systolic right atrial pressure were significantly correlated with the LV position parameters. During ACLS, systolic arterial pressure and systolic right atrial pressure were significantly correlated with DAP-MidLV and DAP-Apex. Conclusions: LV position changed significantly during cardiac arrest compared to the pre-arrest baseline. LV position during CPR had significant correlations with hemodynamic parameters.

Keywords: heart arrest, cardiopulmonary resuscitation, heart ventricle, hemodynamics

Procedia PDF Downloads 190

Authors: M. K. Manoj, V. Pancholi, S. K. Nath

Abstract:

Microalloyed dual phase steels have been prepared by intercritical austenitisation (ICA) treatment of normalized steel at different temperature and time. Water quenching wad carried to obtain different martensite volume fraction (MVF) in DP steels. DP steels and normalized steels have been characterized by optical and scanning electron microscopy, Vickers hardness measurements and tensile properties determination. The effect of MVF and martensite morphology on mechanical properties and fracture behavior of microalloyed dual phase steels have been explained in the present work.

Keywords: dual phase steel, martensite morphology, hardness, tensile strength

Procedia PDF Downloads 329

Authors: Anja Kurz, Marc Flynn, Tobias Good, Marco Caversaccio, Martin Kompis

Abstract:

Bone Anchored Hearing Implants (BAHI) are routinely used in patients with conductive or mixed hearing loss, e.g. if conventional air conduction hearing aids cannot be used. New sound processors and new fitting software now allow the adjustment of parameters such as loudness compression ratios or maximum power output separately. Today it is unclear, how the choice of these parameters influences aided speech understanding in BAHI users. In this prospective experimental study, the effect of varying the compression ratio and lowering the maximum power output in a BAHI were investigated. Twelve experienced adult subjects with a mixed hearing loss participated in this study. Four different compression ratios (1.0; 1.3; 1.6; 2.0) were tested along with two different maximum power output settings, resulting in a total of eight different programs. Each participant tested each program during two weeks. A blinded Latin square design was used to minimize bias. For each of the eight programs, speech understanding in quiet and in noise was assessed. For speech in quiet, the Freiburg number test and the Freiburg monosyllabic word test at 50, 65, and 80 dB SPL were used. For speech in noise, the Oldenburg sentence test was administered. Speech understanding in quiet and in noise was improved significantly in the aided condition in any program, when compared to the unaided condition. However, no significant differences were found between any of the eight programs. In contrast, on a subjective level there was a significant preference for medium compression ratios of 1.3 to 1.6 and higher maximum power output.

Keywords: Bone Anchored Hearing Implant, baha, compression, maximum power output, speech understanding

Procedia PDF Downloads 387

Authors: A. Abdul-Ameer

Abstract:

The equations governing the distance, pressure- volume flow relationships for the pipeline transportation of gaseous mixtures, are considered. A derivation based on differential calculus, for an element of this system model, is addressed. Solutions, yielding the input- output response following pressure changes, are reviewed. The technical problems associated with these analytical results are identified. Procedures resolving these difficulties providing thereby an attractive, simple, analysis route are outlined. Computed responses, validating thereby calculated predictions, are presented.

Keywords: pressure, distance, flow, dissipation, models

Procedia PDF Downloads 475

Authors: Chen Chan Wei

Abstract:

The purpose of this study was to investigate the impact of swim 1500m, 10000m run, VO2 max, and body fat on Olympic distance triathlon competition performance. The subjects were thirteen college triathletes with endurance training, with an average age, height and weight of 20.61±1.04 years (mean ± SD), 171.76±8.54 cm and 65.32±8.14 kg respectively. All subjects were required to take the tests of swim 1500m, run 10000m, VO2 max, body fat, and participate in the Olympic distance triathlon competition. First, the swim 1500m test was taken in the standardized 50m pool, with a depth of 2m, and the 10000m run test on the standardized 400m track. After three days, VO2 max was tested with the MetaMax 3B and body fat was measured with the DEXA machine. After two weeks, all 13 subjects joined the Olympic distance triathlon competition at the 2016 New Taipei City Asian Cup. The relationships between swim 1500m, 10000m run, VO2 max, body fat test, and Olympic distance triathlon competition performance were evaluated using Pearson's product-moment correlation. The results show that 10000m run and body fat had a significant positive correlation with Olympic distance triathlon performance (r=.830, .768), but VO2 max has a significant negative correlation with Olympic distance triathlon performance (r=-.735). In conclusion, for improved non-draft Olympic distance triathlon performance, triathletes should focus on running than swimming training and can be measure VO2 max to prediction triathlon performance. Also, managing body fat can improve Olympic distance triathlon performance. In addition, swimming performance was not significantly correlated to Olympic distance triathlon performance, possibly because the 2016 New Taipei City Asian Cup age group was not a drafting competition. The swimming race is the shortest component of Olympic distance triathlons. Therefore, in a non-draft competition, swimming ability is not significantly correlated with overall performance.

Keywords: triathletes, olympic, non-drafting, correlation

Procedia PDF Downloads 250

Authors: Bogdan Walek, Vladimir Bradac, Radim Farana

Abstract:

Distance learning systems offer useful methods of learning and usually contain final course test or another form of test. The paper proposes web application for evaluating tests using expert system in distance learning systems. Proposed web application is appropriate for didactic tests or tests with results for subsequent studying follow-up courses. Web application works with test questions and uses expert system and LFLC tool for test evaluation. After test evaluation the results are visualized and shown to student.

Keywords: distance learning, test, uncertainty, fuzzy, expert system, student

Procedia PDF Downloads 489

Authors: Efren Lopez Jimenez, Maria Isabel Cajero, J. Irving-Vasqueza

Abstract:

The use and processing of digital images have opened up new opportunities for the resolution of problems of various kinds, such as the calculation of different vegetation indexes, among other things, differentiating healthy vegetation from humid vegetation. However, obtaining images from which these indexes are calculated is still the exclusive subject of active research. In the present work, we propose to obtain these images using a low cost embedded system (Raspberry Pi) and its processing, using a set of libraries of open code called OpenCV, in order to obtain the Normalized Red-Green Difference Index (NGRDI).

Keywords: Raspberry Pi, vegetation index, Normalized Red-Green Difference Index (NGRDI), OpenCV

Procedia PDF Downloads 292

Authors: Guo Wenyu, Qu Youli

Abstract:

A practical and simple self-indexing data structure, Partitioned Elias-Fano (PEF) - Compressed Suffix Arrays (CSA), is built in linear time for the CSA based on PEF indexes. Moreover, the PEF-CSA is compared with two classical compressed indexing methods, Ferragina and Manzini implementation (FMI) and Sad-CSA on different type and size files in Pizza & Chili. The PEF-CSA performs better on the existing data in terms of the compression ratio, count, and locates time except for the evenly distributed data such as proteins data. The observations of the experiments are that the distribution of the φ is more important than the alphabet size on the compression ratio. Unevenly distributed data φ makes better compression effect, and the larger the size of the hit counts, the longer the count and locate time.

Keywords: compressed suffix array, self-indexing, partitioned Elias-Fano, PEF-CSA

Procedia PDF Downloads 253

Authors: Jesus Salmeron, Carmen De Vega, Maria Soledad Vicente, Mireia Olabarria, Olaia Martinez

Abstract:

Dysphagia or difficulty in swallowing affects mostly elder people: 56-78% of the institutionalized and 44% of the hospitalized. Liquid food thickening is a necessary measure in this situation because it reduces the risk of penetration-aspiration. Until now, and as proposed by the American Dietetic Association in 2002, possible consistencies have been categorized in three groups attending to their viscosity: nectar (50-350 mPa•s), honey (350-1750 mPa•s) and pudding (>1750 mPa•s). The adequate viscosity level should be identified for every patient, according to her/his impairment. Nevertheless, a systematic review on dysphagia diet performed recently indicated that there is no evidence to suggest that there is any transition of clinical relevance between the three levels proposed. It was also stated that other physical properties of the bolus (slipperiness, density or cohesiveness, among others) could influence swallowing in affected patients and could contribute to the amount of remaining residue. Texture parameters need to be evaluated as possible alternative to viscosity. The aim of this study was to evaluate the instrumental extrusion-compression test as a possible tool to characterize changes along time in water thickened with various products and in the three theoretical consistencies. Six commercial thickeners were used: NM® (NM), Multi-thick® (M), Nutilis Powder® (Nut), Resource® (R), Thick&Easy® (TE) and Vegenat® (V). All of them with a modified starch base. Only one of them, Nut, also had a 6,4% of gum (guar, tara and xanthan). They were prepared as indicated in the instructions of each product and dispensing the correspondent amount for nectar, honey and pudding consistencies in 300 mL of tap water at 18ºC-20ºC. The mixture was stirred for about 30 s. Once it was homogeneously spread, it was dispensed in 30 mL plastic glasses; always to the same height. Each of these glasses was used as a measuring point. Viscosity was measured using a rotational viscometer (ST-2001, Selecta, Barcelona). Extrusion-compression test was performed using a TA.XT2i texture analyzer (Stable Micro Systems, UK) with a 25 mm diameter cylindrical probe (SMSP/25). Penetration distance was set at 10 mm and a speed of 3 mm/s. Measurements were made at 1, 5, 10, 20, 30, 40, 50 and 60 minutes from the moment samples were mixed. From the force (g)–time (s) curves obtained in the instrumental assays, maximum force peak (F) was chosen a reference parameter. Viscosity (mPa•s) and F (g) showed to be highly correlated and had similar development along time, following time-dependent quadratic models. It was possible to predict viscosity using F as an independent variable, as they were linearly correlated. In conclusion, compression-extrusion test could be an alternative and a useful tool to assess physical characteristics of thickened liquids.

Keywords: compression-extrusion test, dysphagia, texture analyzer, thickener

Procedia PDF Downloads 369

Authors: Fatemeh Abbasi, Arne Hofemeier, Timo Betz

Abstract:

Muscle growth and regeneration critically depend on satellite cells (SCs) which are muscle stem cells located between the basal lamina and myofibres. Upon damage, SCs become activated, enter the cell cycle, and give rise to myoblasts that form new myofibres, while a sub-population self-renew and re-populate the muscle stem cell niche. In aged muscle as well as in certain muscle diseases such as muscular dystrophy, some of the SCs lose their regenerative ability. Although it is demonstrated that the chemical composition of SCs quiescent niche is different from the activated niche, the mechanism initially activated in the SCs remains unknown. While extensive research efforts focused on potential chemical activation, no such factor has been identified to the author’s best knowledge. However, it is substantiated that niche mechanics affects SCs behaviors, such as stemness and engraftment. We hypothesize that mechanical stress in the healthy niche (homeostasis) is different from the regenerative niche and that this difference could serve as an early signal activating SCs upon fiber damage. To investigate this hypothesis, we develop a biomimetic system to reconstitute both, the mechanical and the chemical environment of the SC niche. Cells will be confined between two elastic polyacrylamide (PAA) hydrogels with controlled elastic moduli and functionalized surface chemistry. By controlling the distance between the PAA hydrogel surfaces, we vary the compression forces exerted by the substrates on the cells, while the lateral displacement of the upper hydrogel will create controlled shear forces. To establish such a system, a simplified system is presented. We engineered a sandwich-like configuration of two elastic PAA layer with stiffnesses between 1 and 10 kPa and confined a precursor myoblast cell line (C2C12) in between these layers. Our initial observations in this sandwich model indicate that C2C12 cells show different behaviors under mechanical compression if compared to a control one-layer gel without compression. Interestingly, this behavior is stiffness-dependent. While the shape of C2C12 cells in the sandwich consisting of two stiff (10 kPa) layers was much more elongated, showing almost a neuronal phenotype, the cell shape in a sandwich situation consisting of one stiff and one soft (1 kPa) layer was more spherical. Surprisingly, even in proliferation medium and at very low cell density, the sandwich situation stimulated cell differentiation with increased striation and myofibre formation. Such behavior is commonly found for confluent cells in differentiation medium. These results suggest that mechanical changes in stiffness and applied pressure might be a relevant stimulation for changes in muscle cell behavior.

Keywords: C2C12 cells, compression, force, satellite cells, skeletal muscle

Procedia PDF Downloads 124

Authors: Nikolaos Vassilas, Theocharis Tsenoglou, Djamchid Ghazanfarpour

Abstract:

In this work we explore the capability of the mean shift algorithm as a powerful preprocessing tool for improving the quality of spatial data, acquired from airborne scanners, from densely built urban areas. On one hand, high resolution image data corrupted by noise caused by lossy compression techniques are appropriately smoothed while at the same time preserving the optical edges and, on the other, low resolution LiDAR data in the form of normalized Digital Surface Map (nDSM) is upsampled through the joint mean shift algorithm. Experiments on both the edge-preserving smoothing and upsampling capabilities using synthetic RGB-z data show that the mean shift algorithm is superior to bilateral filtering as well as to other classical smoothing and upsampling algorithms. Application of the proposed methodology for 3D reconstruction of buildings of a pilot region of Athens, Greece results in a significant visual improvement of the 3D building block model.

Keywords: 3D buildings reconstruction, data fusion, data upsampling, mean shift

Procedia PDF Downloads 316

Authors: Eleni Giouli

Abstract:

Distance learning provides a flexible approach to education, enabling busy learners to complete their coursework at their own pace, on their own schedule, and from a convenient location. This flexibility combined with a series of other issues; make the benefits of lifelong distance learning numerous. The purpose of the paper is to investigate whether distance education can contribute to the improvement of adult skills in Greece, highlighting in this way the necessity of the lifelong distance learning. To investigate this goal, a questionnaire is constructed and analyzed based on responses from 3,016 attendees of lifelong distance learning programs in the e-learning of the National and Kapodistrian University of Athens in Greece. In order to do so, a series of relationships is examined including the effects of a) the gender, b) the previous educational level, c) the current employment status, and d) the method used in the distance learning program, on the development of new general, technical, administrative, social, cultural, entrepreneurial and green skills. The basic conclusions that emerge after using a binary logistic framework are that the following factors are critical in order to develop new skills: the gender, the education level and the educational method used in the lifelong distance learning program. The skills more significantly affected by those factors are the acquiring new skills in general, as well as acquiring general, language and cultural, entrepreneurial and green skills, while for technical and social skills only gender and educational method play a crucial role. Moreover, routine skills and social skills are not affected by the four factors included in the analysis.

Keywords: adult skills, distance learning, education, lifelong learning

Procedia PDF Downloads 139

Authors: M. Budakoglu, M. Karaman, A. Abdelnasser, D. Kiran, M. Kumral

Abstract:

About 50 mg lake sediment was digested in two steps. While first stage was completed with 6 ml 37% HCl, 2 ml 65% HNO3 and 1 ml 38-40% HF in an pressure and temperature controlled Teflon beaker using Berghoff Microwave™ at average 135°C, digestion procedure was completed with the addition of 6 ml 5% boric acid solution. REE contents of sediment samples were determined by Perkin Elmer DRC II ICP-MS in Geochemistry Research Laboratories (JAL/GRL) of Faculty of Mines, Istanbul Technical University. Chondrite-normalized REE patterns of Lake Acıgöl sediments show generally high abundance of REE compared to chondritic concentrations, with particular enrichment in LREE [(La/Lu)N = 4.85-19.90], [(La/Lu)N = 7.09-15.14], [(La/Lu)N = 9.42-15.52] and [(La/Lu)N = 7.69-15.63] for the surface sediment and 0-10 cm-, 10-20 cm- and 20-30 cm-subsurface sediments respectively. Also these samples showed flat HREE normalized to chondrite as (La/Sm)N ranging from 2.98 to 4.8 for surface sediments and for subsurface sediments from 3.28 to 3.97 (0-10 cm), 3.57 to 3.94 (10-20 cm) and 3.36 to 3.94 (20-30 cm) while (Gd/Yb)N ranging from 2.14 to 2.93, from 2.03 to 2.76, from 2.26 to 2.79 and from 2.05 to 2.76 from the surface and subsurface sediments respectively. Moreover, their REE profiles are similar to profiles of the continental collision basin (CCB) with negative Eu anomalies. In addition, their REE patterns illustrate generally low abundance of REE compared to concentrations of NASC, PAAS and UCC with very slight enrichment of LREE and positive Eu* anomalies. Therefore there is no comparable between our samples of surface and subsurface sediments and these types of international sediments.

Keywords: chondrite-normalized REE patterns, hypersaline lake, surface sediments, subsurface sediments, Lake Acıgöl, Turkey

Procedia PDF Downloads 521

Authors: Gayani K. Nandasiri, Tilak Dias, William Hurley

Abstract:

Venous disease of human lower limb could range from minor asymptomatic incompetence of venous valves to chronic venous ulceration. The sheer prevalence of varicose veins and its associated significant costs of treating late complications such as chronic ulcers contribute to a higher burden on health care resources. In most of western countries with developed health care systems, treatment costs associated with Venous disease accounts for a considerable portion of their total health care budget, and it has become a high-cost burden to National Health Service (NHS), UK. The established gold standard of treatment for the venous disease is the graduated compression, where the pressure at the ankle being highest and decreasing towards the knee and thigh. Currently, medical practitioners use two main methods to treat venous disease; i.e. compression bandaging and compression stockings. Both these systems have their own disadvantages which lead to the current programme of research. The aim of the present study is to revolutionize the compression therapy by using a novel active compression system to deliver a controllable and more accurate pressure profiles using a series of inflatable mini bladders. Two types of commercially available silicones were tested for the application. The mini bladders were designed with a special fabrication procedure to provide required pressure profiles, and a series of experiments were conducted to characterise the mini bladders. The inflation/deflation heights of these mini bladders were investigated experimentally and using a finite element model (FEM), and the experimental data were compared to the results obtained from FEM simulations, which showed 70-80% agreement. Finally, the mini bladders were tested for its pressure transmittance characteristics, and the results showed a 70-80% of inlet air pressure transmitted onto the treated surface.

Keywords: finite element analysis, graduated compression, inflatable bladders, venous disease

Procedia PDF Downloads 185

Authors: M. J. Kang, Y. N. Jo, H. H. Yoo

Abstract:

Pendulum tests were used to identify a stretch reflex and diagnose spasticity. Some researches tried to make a mathematical model to simulate the motions. Thighs are subject to compressive forces due to gravity during a pendulum test. Therefore, it affects knee trajectories. However, the most studies on the pendulum tests did not consider that conditions. We used Kelvin-Voight model as compression model of skin and muscles. In this study, we investigated viscoelastic behaviors of skin and muscles using gelatin blocks from experiments of the vibration of the compliantly supported beam. Then we calculated a dynamic stiffness and loss factors from the experiment and estimated a damping coefficient of the model. We also did pendulum tests of human lower limbs to validate the stiffness and damping coefficient of a skin model. To simulate the pendulum motion, we derive equations of motion. We used stretch reflex activation model to estimate muscle forces induced by the stretch reflex. To validate the results, we compared the activation with electromyography signals during experiments. The compression behavior of skin and muscles in this study can be applied to analyze sitting posture as wee as developing surgical techniques.

Keywords: Kelvin-Voight model, pendulum test, skin and muscles under compression, stretch reflex

Procedia PDF Downloads 447

Authors: Sahar Mobeen, Anam Rafique, Irum Baig

Abstract:

Acoustic echo cancellation in multichannel is a system identification application. In real time environment, signal changes very rapidly which required adaptive algorithms such as Least Mean Square (LMS), Leaky Least Mean Square (LLMS), Normalized Least Mean square (NLMS) and average (AFA) having high convergence rate and stable. LMS and NLMS are widely used adaptive algorithm due to less computational complexity and AFA used of its high convergence rate. This research is based on comparison of acoustic echo (generated in a room) cancellation thorough LMS, LLMS, NLMS, AFA and newly proposed average normalized leaky least mean square (ANLLMS) adaptive filters.

Keywords: LMS, LLMS, NLMS, AFA, ANLLMS

Procedia PDF Downloads 566

Authors: Samira Abbaspour

Abstract:

Soil contamination by oil industry is unavoidable issue; irrespective of environmental impact, which occurs during the process of soil contaminating and remediating. Effect of this phenomenon on the geotechnical properties of the soil has not been investigated thoroughly. Some researchers studied the environmental aspects of these phenomena more than geotechnical point of view. In this research, compaction and unconfined compression tests were conducted on samples of natural, contaminated and treated soil after 50 days of bio-treatment. The results manifest that increasing the amount of crude oil, leads to decreased values of maximum dry density and optimum water content and increased values of unconfined compression strength (UCS). However, almost 65% of this contamination terminated by using a Bioremer as a bioremediation agent. Foremost, as bioremediation takes place, values of maximum dry density, unconfined compression strength and failure strain increase.

Keywords: contamination, shear strength, compaction, oil contamination

Procedia PDF Downloads 185

Authors: Dongheon Shin, Kyungnam Ko, Jongchul Huh

Abstract:

The investigation on wind turbine degradation was carried out using the nacelle wind data. The three Vestas V80-2MW wind turbines of Sungsan wind farm in Jeju Island, South Korea were selected for this work. The SCADA data of the wind farm for five years were analyzed to draw power curve of the turbines. It is assumed that the wind distribution is the Rayleigh distribution to calculate the normalized capacity factor based on the drawn power curve of the three wind turbines for each year. The result showed that the reduction of power output from the three wind turbines occurred every year and the normalized capacity factor decreased to 0.12%/year on average.

Keywords: wind energy, power curve, capacity factor, annual energy production

Procedia PDF Downloads 433

Authors: Sunil Verma

Abstract:

This report is concerned with study of autoignition delay characterstics of n-pentane. Experiments are done for different equivalents ratio on Rapid compression machine. Dependence of autoignition delay period is clearly explained from lean to rich mixtures. Equivalence ratio is varied from 0.33 to 0.6.

Keywords: combustion, autoignition, ignition delay, rapid compression machine

Procedia PDF Downloads 351

Authors: Saida Dorbani, M'hammed Badaoui, Djilali Benouar

Abstract:

This paper deals with the effect of the building design and epicentral distance on the storey lateral displacement, for several reinforced concrete buildings (6, 9 and 12 stories), with three floor plans: symmetric, mono symmetric, and unsymmetrical. These structures are subjected to seismic accelerations from the Boumerdes earthquake (Algeria, May 21st, Mw=6.5). The objective of this study is to highlight the impact of the fundamental period and epicentral distance on storey displacements for a given earthquake. The seismic lateral displacement is carried out in both longitudinal and transverse direction by the response spectrum method.

Keywords: natural period, epicenter distance, reinforced concrete buildings, storey displacement

Procedia PDF Downloads 263

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

Abstract:

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

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

Procedia PDF Downloads 220