Search results for: safety performance functions
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 17247

Search results for: safety performance functions

9087 Carbon Nanofibers as the Favorite Conducting Additive for Mn₃O₄ Catalysts for Oxygen Reactions in Rechargeable Zinc-Air Battery

Authors: Augustus K. Lebechi, Kenneth I. Ozoemena

Abstract:

Rechargeable zinc-air batteries (RZABs) have been described as one of the most viable next-generation ‘beyond-the-lithium-ion’ battery technologies with great potential for renewable energy storage. It is safe, with a high specific energy density (1086 Wh/kg), environmentally benign, and low-cost, especially in resource-limited African countries. For widespread commercialization, the sluggish oxygen reaction kinetics pose a major challenge that impedes the reversibility of the system. Hence, there is a need for low-cost and highly active bifunctional electrocatalysts. Manganese oxide catalysts on carbon conducting additives remain the best couple for the realization of such low-cost RZABs. In this work, hausmannite Mn₃O₄ nanoparticles were synthesized through the annealing method from commercial electrolytic manganese dioxide (EMD), multi-walled carbon nanotubes (MWCNTs) were synthesized via the chemical vapor deposition (CVD) method and carbon nanofibers (CNFs) were synthesized via the electrospinning process with subsequent carbonization. Both Mn₃O₄ catalysts and the carbon conducting additives (MWCNT and CNF) were thoroughly characterized using X-ray powder diffraction spectroscopy (XRD), scanning electron microscopy (SEM), thermogravimetry analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Composite electrocatalysts (Mn₃O₄/CNT and Mn₃O₄/CNF) were investigated for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in an alkaline medium. Using the established electrocatalytic modalities for evaluating the electrocatalytic performance of materials (including double layer, electrochemical active surface area, roughness factor, specific current density, and catalytic stability), CNFs proved to be the most efficient conducting additive material for the Mn₃O₄ catalyst. From the DFT calculations, the higher performance of the CNFs over the MWCNTs is related to the ability of the CNFs to allow for a more favorable distribution of the d-electrons of the manganese (Mn) and enhanced synergistic effect with Mn₃O₄ for weaker adsorption energies of the oxygen intermediates (O*, OH* and OOH*). In a proof-of-concept, Mn₃O₄/CNF was investigated as the air cathode for rechargeable zinc-air battery (RZAB) in a micro-3D-printed cell configuration. The RZAB showed good performance in terms of open circuit voltage (1.77 V), maximum power density (177.5 mW cm-2), areal-discharge energy and cycling stability comparable to Pt/C (20 wt%) + IrO2. The findings here provide fresh physicochemical perspectives on the future design and utility of CNFs for developing manganese-based RZABs.

Keywords: bifunctional electrocatalyst, oxygen evolution reaction, oxygen reduction reactions, rechargeable zinc-air batteries.

Procedia PDF Downloads 50
9086 Residential High-Rises and Meaningful Places: Missing Actions in the Isle of Dogs Regeneration

Authors: Elena Kalcheva, Ahmad Taki, Yuri Hadi

Abstract:

Urban regeneration often includes residential high-rises as a way of optimum use of land. However, high-rises are in many cases connected to placelessness, this is not due to some intrinsic characteristic of the typology, but more to a failure to provide meaningful places in connection to them. The reason to study the Isle of the Dogs regeneration is the successful process that led to vibrant area with strong identity and social sustainability. Therefore, the purpose of this research is to identify the gaps into the sound strategy for the development of the area and in its implementation which will make the place more sustainable. The paper addresses four research questions: are the residential high-rises supporting a proper physical form; is there deployed properly scaled mix of land uses and functions in connection with residential high-rises; are there possible quality activities in quality places near the residential high-rises; and is there a strong sense of place created with the residential high-rise buildings and their surroundings. The methodology relies on observational survey of the researched area together with structured questions, to evaluate the external qualities of the residential high-rises and their surroundings. Visual information can help identify the mistakes and the omissions of the provided project examples. It can provide insight on how can be improved imageability, legibility and human scale. In this connection, the paper argues that although the quality of the architecture of the high-rises is superb, there is a failure to create meaningful, high quality public realm in connection with them. As such, it does not function as well as the designers intended to do: the functional quality of the public realm is quite low. The implications of the study suggest that actions need to take place in order to improve and foster further regeneration of the area.

Keywords: high-rises, isle of the dogs, public realm, regeneration

Procedia PDF Downloads 264
9085 Road Condition Monitoring Using Built-in Vehicle Technology Data, Drones, and Deep Learning

Authors: Judith Mwakalonge, Geophrey Mbatta, Saidi Siuhi, Gurcan Comert, Cuthbert Ruseruka

Abstract:

Transportation agencies worldwide continuously monitor their roads' conditions to minimize road maintenance costs and maintain public safety and rideability quality. Existing methods for carrying out road condition surveys involve manual observations of roads using standard survey forms done by qualified road condition surveyors or engineers either on foot or by vehicle. Automated road condition survey vehicles exist; however, they are very expensive since they require special vehicles equipped with sensors for data collection together with data processing and computing devices. The manual methods are expensive, time-consuming, infrequent, and can hardly provide real-time information for road conditions. This study contributes to this arena by utilizing built-in vehicle technologies, drones, and deep learning to automate road condition surveys while using low-cost technology. A single model is trained to capture flexible pavement distresses (Potholes, Rutting, Cracking, and raveling), thereby providing a more cost-effective and efficient road condition monitoring approach that can also provide real-time road conditions. Additionally, data fusion is employed to enhance the road condition assessment with data from vehicles and drones.

Keywords: road conditions, built-in vehicle technology, deep learning, drones

Procedia PDF Downloads 105
9084 Performance Analysis of Modified Solar Water Heating System for Climatic Condition of Allahabad, India

Authors: Kirti Tewari, Rahul Dev

Abstract:

Solar water heating is a thermodynamic process of heating water using sunlight with the help of solar water heater. Thus, solar water heater is a device used to harness solar energy. In this paper, a modified solar water heating system (MSWHS) has been proposed over flat plate collector (FPC) and Evacuated tube collector (ETC). The modifications include selection of materials other than glass, and glass wool which are conventionally used for fabricating FPC and ETC. Some modifications in design have also been proposed. Its collector is made of double layer of semi-cylindrical acrylic tubes and fibre reinforced plastic (FRP) insulation base. Water tank is made of double layer of acrylic sheet except base and north wall. FRP is used in base and north wall of the water tank. A concept of equivalent thickness has been utilised for calculating the dimensions of collector plate, acrylic tube and tank. A thermal model for the proposed design of MSWHS is developed and simulation is carried out on MATLAB for the capacity of 200L MSWHS having collector area of 1.6 m2, length of acrylic tubes of 2m at an inclination angle 25° which is taken nearly equal to the latitude of the given location. Latitude of Allahabad is 24.45° N. The results show that the maximum temperature of water in tank and tube has been found to be 71.2°C and 73.3°C at 17:00hr and 16:00hr respectively in March for the climatic data of Allahabad. Theoretical performance analysis has been carried out by varying number of tubes of collector, the tank capacity and climatic data for given months of winter and summer.

Keywords: acrylic, fibre reinforced plastic, solar water heating, thermal model, conventional water heaters

Procedia PDF Downloads 328
9083 Author Profiling: Prediction of Learners’ Gender on a MOOC Platform Based on Learners’ Comments

Authors: Tahani Aljohani, Jialin Yu, Alexandra. I. Cristea

Abstract:

The more an educational system knows about a learner, the more personalised interaction it can provide, which leads to better learning. However, asking a learner directly is potentially disruptive, and often ignored by learners. Especially in the booming realm of MOOC Massive Online Learning platforms, only a very low percentage of users disclose demographic information about themselves. Thus, in this paper, we aim to predict learners’ demographic characteristics, by proposing an approach using linguistically motivated Deep Learning Architectures for Learner Profiling, particularly targeting gender prediction on a FutureLearn MOOC platform. Additionally, we tackle here the difficult problem of predicting the gender of learners based on their comments only – which are often available across MOOCs. The most common current approaches to text classification use the Long Short-Term Memory (LSTM) model, considering sentences as sequences. However, human language also has structures. In this research, rather than considering sentences as plain sequences, we hypothesise that higher semantic - and syntactic level sentence processing based on linguistics will render a richer representation. We thus evaluate, the traditional LSTM versus other bleeding edge models, which take into account syntactic structure, such as tree-structured LSTM, Stack-augmented Parser-Interpreter Neural Network (SPINN) and the Structure-Aware Tag Augmented model (SATA). Additionally, we explore using different word-level encoding functions. We have implemented these methods on Our MOOC dataset, which is the most performant one comparing with a public dataset on sentiment analysis that is further used as a cross-examining for the models' results.

Keywords: deep learning, data mining, gender predication, MOOCs

Procedia PDF Downloads 127
9082 IL-33 Production in Murine Macrophages via PGE2-E Prostanoid Receptor 2/4 Signaling

Authors: Sachin K. Samuchiwal, Barbara Balestrieri, Amanda Paskavitz, Hannah Raff, Joshua A. Boyce

Abstract:

IL-33, a recently discovered member of the IL-1 cytokine family, binds to the TLR/IL1R super family receptor ST2 and induces type 2 immune responses. IL-33 is constitutively expressed in structural cells at barrier sites such as skin, lung, and intestine, and also inducibly expressed by hematopoietic cells including macrophages. Stimulation of macrophages by Lipopolysaccharide (LPS) can induce de novo IL-33 expression, and also causes the production of prostaglandin-E2 (PGE2) via cyclooxygenase (COX)-2 and microsomal PGE2 synthase-1 (mPGES-1). Because PGE2 can regulate macrophage functions through both autocrine and paracrine mechanisms, the potential interplay of endogenous PGE2 on IL-33 production was explored. Bone-marrow derived murine macrophages (bmMF) that lack either mPGES-1 or EP2 receptor expression were stimulated with LPS in the absence or presence of exogenous PGE2 along with pharmacological agonists and antagonists. The study results demonstrate that endogenous PGE2 markedly enhances LPS-induced IL-33 production by bmMFs via EP2 receptors. Moreover, exogenous PGE2 can amplify LPS-induced IL-33 expression dominantly by EP2 and partly by EP4 receptors by a pathway involving cAMP and exchange protein activated by cAMP (EPAC), but not protein kinase A (PKA). Though both IL-33 production and PGE2 generation in response to LPS require activation of both p38 MAPK and NF-κB, PGE2 did not influence this activation. In conclusion, it is demonstrated that endogenous PGE2 signaling through EP2 and EP4 receptors is a prerequisite for LPS-induced IL-33 production in bmMFs and the underlying cAMP mediated pathway involves EPAC. Since IL-33 is a critical pro-inflammatory cytokine in various pathological disorders, this PGE2-EP2/EP4-cAMP mediated pathway can be exploited to intervene in IL-33 driven pathologies.

Keywords: bone marrow macrophages, EPAC, IL-33, PGE2

Procedia PDF Downloads 168
9081 Competition between Verb-Based Implicit Causality and Theme Structure's Influence on Anaphora Bias in Mandarin Chinese Sentences: Evidence from Corpus

Authors: Linnan Zhang

Abstract:

Linguists, as well as psychologists, have shown great interests in implicit causality in reference processing. However, most frequently-used approaches to this issue are psychological experiments (such as eye tracking or self-paced reading, etc.). This research is a corpus-based one and is assisted with statistical tool – software R. The main focus of the present study is about the competition between verb-based implicit causality and theme structure’s influence on anaphora bias in Mandarin Chinese sentences. In Accessibility Theory, it is believed that salience, which is also known as accessibility, and relevance are two important factors in reference processing. Theme structure, which is a special syntactic structure in Chinese, determines the salience of an antecedent on the syntactic level while verb-based implicit causality is a key factor to the relevance between antecedent and anaphora. Therefore, it is a study about anaphora, combining psychology with linguistics. With analysis of the sentences from corpus as well as the statistical analysis of Multinomial Logistic Regression, major findings of the present study are as follows: 1. When the sentence is stated in a ‘cause-effect’ structure, the theme structure will always be the antecedent no matter forward biased verbs or backward biased verbs co-occur; in non-theme structure, the anaphora bias will tend to be the opposite of the verb bias; 2. When the sentence is stated in a ‘effect-cause’ structure, theme structure will not always be the antecedent and the influence of verb-based implicit causality will outweigh that of theme structure; moreover, the anaphora bias will be the same with the bias of verbs. All the results indicate that implicit causality functions conditionally and the noun in theme structure will not be the high-salience antecedent under any circumstances.

Keywords: accessibility theory, anaphora, theme strcture, verb-based implicit causality

Procedia PDF Downloads 184
9080 The Effects of Garlic (Allium sativum) in the Diet on Some Serum Biochemical Parameters of Oscar Fish (Astronotus ocellatus)

Authors: Ali Saghaei, Negar Ghotbeddin, Ebrahim Rajabzadeh Ghatrami, Milad Maniat

Abstract:

The use of herbs as natural additives in fish diets are used to enhance the efficiency and safety systems. The use of herbs, garlic, due to the structure and composition of it has beneficial role in human nutrition and animal nutrition. This study was conducted evaluate the effect different levels of garlic (Allium sativum) powder on the some serum biochemical parameters of Oscar fish (Astronotus ocellatus). Fish were divided into four groups fed on diets containing garlic in different levels; 5 g kg˗1, 10 g kg-1, 20 g kg-1, 30 g kg-1 diet and the control group diet was without garlic. A total number of 300 fish was used and Triplicate groups of Oscar fish with initial weight of 12.43±0.24 g were hand-fed to visual satiation at three meals per day. The experiment extended for two months. Total Protein (TP), Albumin (ALB), Globulin (GLB) and Albumin/Globulin (A/G) ratio, were determined. Based on the results, no significant differences were seen among treatments and control groups during the experimental period for TP, ALB, GLB, and A/G ratio (p > 0.05). Although, the highest amount of serum total protein and globulin levels were observed in diet containing 10 g kg-1 of garlic. Also, the highest value of albumin and A/G were observed in diet containing 20 g kg-1 of garlic, but there were no significant difference with other treatments. The results of this study show that addition of garlic Allium sativum to fish diet can improve fish health.

Keywords: garlic (Allium sativum), serum, Oscar fish (Astronotus ocellatus), iran

Procedia PDF Downloads 470
9079 Comparison of Deep Learning and Machine Learning Algorithms to Diagnose and Predict Breast Cancer

Authors: F. Ghazalnaz Sharifonnasabi, Iman Makhdoom

Abstract:

Breast cancer is a serious health concern that affects many people around the world. According to a study published in the Breast journal, the global burden of breast cancer is expected to increase significantly over the next few decades. The number of deaths from breast cancer has been increasing over the years, but the age-standardized mortality rate has decreased in some countries. It’s important to be aware of the risk factors for breast cancer and to get regular check- ups to catch it early if it does occur. Machin learning techniques have been used to aid in the early detection and diagnosis of breast cancer. These techniques, that have been shown to be effective in predicting and diagnosing the disease, have become a research hotspot. In this study, we consider two deep learning approaches including: Multi-Layer Perceptron (MLP), and Convolutional Neural Network (CNN). We also considered the five-machine learning algorithm titled: Decision Tree (C4.5), Naïve Bayesian (NB), Support Vector Machine (SVM), K-Nearest Neighbors (KNN) Algorithm and XGBoost (eXtreme Gradient Boosting) on the Breast Cancer Wisconsin Diagnostic dataset. We have carried out the process of evaluating and comparing classifiers involving selecting appropriate metrics to evaluate classifier performance and selecting an appropriate tool to quantify this performance. The main purpose of the study is predicting and diagnosis breast cancer, applying the mentioned algorithms and also discovering of the most effective with respect to confusion matrix, accuracy and precision. It is realized that CNN outperformed all other classifiers and achieved the highest accuracy (0.982456). The work is implemented in the Anaconda environment based on Python programing language.

Keywords: breast cancer, multi-layer perceptron, Naïve Bayesian, SVM, decision tree, convolutional neural network, XGBoost, KNN

Procedia PDF Downloads 61
9078 A Simple Model for Solar Panel Efficiency

Authors: Stefano M. Spagocci

Abstract:

The efficiency of photovoltaic panels can be calculated with such software packages as RETScreen that allow design engineers to take financial as well as technical considerations into account. RETScreen is interfaced with meteorological databases, so that efficiency calculations can be realistically carried out. The author has recently contributed to the development of solar modules with accumulation capability and an embedded water purifier, aimed at off-grid users such as users in developing countries. The software packages examined do not allow to take ancillary equipment into account, hence the decision to implement a technical and financial model of the system. The author realized that, rather than re-implementing the quite sophisticated model of RETScreen - a mathematical description of which is anyway not publicly available - it was possible to drastically simplify it, including the meteorological factors which, in RETScreen, are presented in a numerical form. The day-by-day efficiency of a photovoltaic solar panel was parametrized by the product of factors expressing, respectively, daytime duration, solar right ascension motion, solar declination motion, cloudiness, temperature. For the sun-motion-dependent factors, positional astronomy formulae, simplified by the author, were employed. Meteorology-dependent factors were fitted by simple trigonometric functions, employing numerical data supplied by RETScreen. The accuracy of our model was tested by comparing it to the predictions of RETScreen; the accuracy obtained was 11%. In conclusion, our study resulted in a model that can be easily implemented in a spreadsheet - thus being easily manageable by non-specialist personnel - or in more sophisticated software packages. The model was used in a number of design exercises, concerning photovoltaic solar panels and ancillary equipment like the above-mentioned water purifier.

Keywords: clean energy, energy engineering, mathematical modelling, photovoltaic panels, solar energy

Procedia PDF Downloads 38
9077 Ecofriendly Multi-Layer Polymer Treatment for Hydrophobic and Water Repellent Porous Cotton Fabrics

Authors: Muhammad Zahid, Ilker S. Bayer, Athanassia Athanassiou

Abstract:

Fluorinated polymers having C8 chemistry (chemicals with 8 fluorinated carbon atoms) are well renowned for their excellent low surface tension and water repelling properties. However, these polymers degrade into highly toxic heavy perfluoro acids in the environment. When the C8 chemistry is reduced to C6 chemistry, this environmental concern is eliminated at the expense of reduced liquid repellent performance. In order to circumvent this, in this study, we demonstrate pre-treatment of woven cotton fabrics with a fluorinated acrylic copolymer with C6 chemistry and subsequently with a silicone polymer to render them hydrophobic. A commercial fluorinated acrylic copolymer was blended with silica nanoparticles to form hydrophobic nano-roughness on cotton fibers and a second coating layer of polydimethylsiloxane (PDMS) was applied on the fabric. A static water contact angle (for 5µl) and rolling angle (for 12.5µl) of 147°±2° and 31° were observed, respectively. Hydrostatic head measurements were also performed to better understand the performance with 26±1 cm and 2.56kPa column height and static pressure respectively. Fabrication methods (with rod coater etc.) were kept simple, reproducible, and scalable and cost efficient. Moreover, the robustness of applied coatings was also evaluated by sonication cleaning and abrasion methods. Water contact angle (WCA), water shedding angle (WSA), hydrostatic head, droplet bouncing-rolling off and prolonged staining tests were used to characterize hydrophobicity of materials. For chemical and morphological analysis, various characterization methods were used such as attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM) and scanning electron microscopy (SEM).

Keywords: fluorinated polymer, hydrophobic, polydimethylsiloxane, water contact angle

Procedia PDF Downloads 312
9076 Evaluation and Association of Thyroid Function Tests with Liver Function Parameters LDL and LDH Level Before and after I131 Therapy

Authors: Sabika Rafiq, Rubaida Mehmood, Sajid Hussain, Atia Iqbal

Abstract:

Background and objectives: The pathogenesis of liver function abnormalities and cardiac dysfunction in hyperthyroid patients after I131 treatment is still unclear. This study aimed to determine the effects of radioiodine I131 on liver function parameters, lactate dehydrogenase (LDH) and low-density lipoproteins (LDL) before and after I131 therapy hyperthyroidism patients. Material & Methods: A total of 52 patients of hyperthyroidism recommended for I131were involved in this study with ages ranging from 12–65 years (mean age=38.6±14.8 & BMI=11.5±3.7). The significance of the differences between the results of 1st, 2nd and 3rd-time serum analysis was assessed by unpaired student’s t-test. Associations between the parameters were assessed by Spearman correlation analysis. Results: Significant variations were observed for thyroid profile free FT3 (p=0.04), FT4 (p=0.01), TSH (p=0.005) during the follow-up treatment. Before taking I131 (serum analyzed at 1st time), negative correlation of FT3 with AST (r=-0.458, p=0.032) and LDL (r=-0.454, p=0.039) were observed. During 2nd time (after stopping carbimazole), no correlation was assessed. Two months after the administration of I131 drops, a significant negative association of FT3 (r=-0.62, p=0.04) and FT4(r=-0.61, p=0.02) with ALB were observed. FT3(r=-0.82, p=0.00) & FT4 (r=-0.71, p=0.00) also showed negative correlation with LDL after I131 therapy. Whereas TSH showed significant positive association with ALB (r=0.61, p=0.01) and LDL (r=0.70, p=0.00) respectively. Conclusion: Current findings suggested that the association of TFTs with biochemical parameters in patients with goiter recommended for iodine therapy is an important diagnostic and therapeutic tool. The significant changes increased in transaminases and low-density lipoprotein levels after taking I131drops are alarming signs for heart and liver function abnormalities and warrant physicians' attention on an urgent basis.

Keywords: hyperthyroidism, carbimazole, radioiodine I131, liver functions, low-density lipoprotein

Procedia PDF Downloads 145
9075 Transcriptomic Response of Calmodulin Encoding Gene (CaM) in Pesticide Utilizing Talaromyces Fungal Strains

Authors: M. D. Asemoloye, S. G. Jonathan, A. Rafiq, O. J. Olawuyi, D. O. Adejoye

Abstract:

Calmodulin is one of the intracellular calcium proteins that regulates large spectrum of enzymes and cellular functions including metabolism of cyclic nucleotides and glycogen. The potentials of calmodulin gene in fungi necessitates their genetic response and their strong cassette of enzyme secretions for pesticide degradation. Therefore, this study was carried out to investigate the ‘Transcriptomic’ response of calmodulin encoding genes in Talaromyces fungi in response to 2, 2-dichlorovinyl dimethyl phosphate (DDVP or Dichlorvos) an organophosphate pesticide and γ-Hexachlorocyclohexane (Lindane) an organochlorine pesticide. Fungi strains isolated from rhizosphere from grasses rhizosphere in pesticide polluted sites were subjected to percentage incidence test. Two most frequent fungi were further characterized using ITS gene amplification (ITS1 and ITS4 combinations), they were thereafter subjected to In-vitro DDVP and lindane tolerance tests at different concentrations. They were also screened for presence and expression of calmodulin gene (caM) using RT-PCR technique. The two Talaromyces strains had the highest incidence of 50-72% in pesticide polluted site, they were both identified as Talaromyces astroroseus asemoG and Talaromyces purpurogenum asemoN submitted in NCBI gene-bank with accession numbers KY488464 and KY488468 respectively. T. astroroseus KY488464 tolerated DDVP (1.23±0.023 cm) and lindane (1.11±0.018 cm) at 25 % concentration while T. purpurogenum KY488468 tolerated DDVP (1.33±0.061 cm) and lindane (1.54±0.077 cm) at this concentration. Calmodulin gene was detected in both strains, but RT-PCR expression of caM gene revealed at 900-1000 bp showed an under-expression of caM in T. astrorosues KY488464 but overexpressed in T. purpurogenum KY488464. Thus, the calmodulin gene response of these fungal strains to both pesticides could be considered in monitoring the potentials of fungal strains to pesticide tolerance and bioremediation of pesticide in polluted soil.

Keywords: Calmodulin gene, pesticide, RT-PCR, talaromyces, tolerance

Procedia PDF Downloads 213
9074 Temperature Dependent Current-Voltage (I-V) Characteristics of CuO-ZnO Nanorods Based Heterojunction Solar Cells

Authors: Venkatesan Annadurai, Kannan Ethirajalu, Anu Roshini Ramakrishnan

Abstract:

Copper oxide (CuO) and zinc oxide (ZnO) based coaxial (CuO-ZnO nanorods) heterojunction has been the interest of various research communities for solar cells, light emitting diodes (LEDs) and photodetectors applications. Copper oxide (CuO) is a p-type material with the band gap of 1.5 eV and it is considered to be an attractive absorber material in solar cells applications due to its high absorption coefficient and long minority carrier diffusion length. Similarly, n-type ZnO nanorods possess many attractive advantages over thin films such as, the light trapping ability and photosensitivity owing to the presence of oxygen related hole-traps at the surface. Moreover, the abundant availability, non-toxicity, and inexpensiveness of these materials make them suitable for potentially cheap, large area, and stable photovoltaic applications. However, the efficiency of the CuO-ZnO nanorods heterojunction based devices is greatly affected by interface defects which generally lead to the poor performance. In spite of having much potential, not much work has been carried out to understand the interface quality and transport mechanism involved across the CuO-ZnO nanorods heterojunction. Therefore, a detailed investigation of CuO-ZnO heterojunction is needed to understand the interface which affects its photovoltaic performance. Herein, we have fabricated the CuO-ZnO nanorods based heterojunction by simple hydrothermal and electrodeposition technique and investigated its interface quality by carrying out temperature (300 –10 K) dependent current-voltage (I-V) measurements under dark and illumination of visible light. Activation energies extracted from the temperature dependent I-V characteristics reveals that recombination and tunneling mechanism across the interfacial barrier plays a significant role in the current flow.

Keywords: heterojunction, electrical transport, nanorods, solar cells

Procedia PDF Downloads 215
9073 Pragmatic Language Characteristics of Individuals with Asperger Syndrome: Systematic Literature Review and Meta-analysis

Authors: Sadeq Alyaari, Muhammad Alkhunayn, Montaha Al Yaari, Ayman Al Yaari, Ayah Al Yaari, Adham Al Yaari, Sajedah Al Yaari, Fatehi Eissa

Abstract:

Introduction. The purpose of this Systematic Literature Review and Meta-analysis ((SLR & Meta-analysis) was to examine the differences between Asperger syndrome (AS) individuals and typically developing and achieving individuals (TD) regarding language competence and how these differences related to AS individuals’ age and the significance such differences add to our knowledge of understanding their language performance as issues that are still underdiagnosed and ill-treated entities. Methods. The study followed SLR & Meta-analysis protocol and was armed with data of 456 AS subjects and controls (231 and 225, respectively) abstracted from 14 studies that have been collected from different electronic bibliographic databases including web of science, Scopus, EMBASE, Cochrane library, PubMed, PsycInfo and google scholar along with unpublished literature. Results. Outlined results show deterioration in language competence of AS subjects in comparison to TD controls. Such deterioration impairs conversational implicature more than it does conventional maxims of AS individuals’ pragmatic language and has no relationship with their age. Results also show that the difference in intelligence features of the mental reality in the language competence becomes smaller with increasing age and that the difference in representational content features becomes larger. Conclusions. These findings help experts in the field not only predict pragmatic language impairments in AS individuals but also enable AS individuals themselves to decode and/or interpret speech inputs; therefore, perceive the world around them and interact with their community members. Outcomes should be considered to lay out a path for further exploration of genetics, etiology, and response to treatment of all these premises that are currently unsearched in AS individuals.

Keywords: pragmatic language characteristics, language competence, mental faculty, mental reality, features, language performance, pragmatics, conventional maxims

Procedia PDF Downloads 22
9072 Excited State Structural Dynamics of Retinal Isomerization Revealed by a Femtosecond X-Ray Laser

Authors: Przemyslaw Nogly, Tobias Weinert, Daniel James, Sergio Carbajo, Dmitry Ozerov, Antonia Furrer, Dardan Gashi, Veniamin Borin, Petr Skopintsev, Kathrin Jaeger, Karol Nass, Petra Bath, Robert Bosman, Jason Koglin, Matthew Seaberg, Thomas Lane, Demet Kekilli, Steffen Brünle, Tomoyuki Tanaka, Wenting Wu, Christopher Milne, Thomas A. White, Anton Barty, Uwe Weierstall, Valerie Panneels, Eriko Nango, So Iwata, Mark Hunter, Igor Schapiro, Gebhard Schertler, Richard Neutze, Jörg Standfuss

Abstract:

Ultrafast isomerization of retinal is the primary step in a range of photoresponsive biological functions including vision in humans and ion-transport across bacterial membranes. We studied the sub-picosecond structural dynamics of retinal isomerization in the light-driven proton pump bacteriorhodopsin using an X-ray laser. Twenty snapshots with near-atomic spatial and temporal resolution in the femtosecond regime show how the excited all-trans retinal samples conformational states within the protein binding pocket prior to passing through a highly-twisted geometry and emerging in the 13-cis conformation. The aspartic acid residues and functional water molecules in proximity of the retinal Schiff base respond collectively to formation and decay of the initial excited state and retinal isomerization. These observations reveal how the protein scaffold guides this remarkably efficient photochemical reaction.

Keywords: bacteriorhodopsin, free-electron laser, retinal isomerization mechanism, time-resolved crystallography

Procedia PDF Downloads 230
9071 Knowledge of Operation Rooms’ Staff toward Sources, Prevention and Control of Fires at Governmental Hospitals in Sana’a, Yemen

Authors: Abdulnasser Ahmed Haza’a, Marzoq Ali Odhah, Saddam Ahmed Al-Ahdal, Abdulfatah Saleh Al-Jaradi, Gamil Ghaleb Alrubaiee

Abstract:

Patient safety in hospitals is an essential professional indicator that should be noticed. The threat of fires is potentially the most dangerous risk that could harm patients and personnel. The aim of the study is to assess the knowledge of operating room (OR) staff toward prevention and control sources of fires. Between March 1 and March 30, 2022, data collection was done. A descriptive cross-sectional study was conducted. The sample of the study consisted of 89 OR staff from different governmental hospitals. Convenient sampling was applied to select the sample size. Official approvals were obtained from selected settings for start collection data. Data were collected using a close-ended questionnaire and tested for knowledge. This study was conducted in four governmental hospitals in Sana'a, Yemen. Most of the OR staff were male. Of these, 50.6% of them were operation technician professionals. More than two-thirds of OR staff have less than ten years of experience; 93% of OR staff had inadequate knowledge of sources of fires, and inadequate knowledge of them toward controls and prevention of fires (73%, 79.8%), respectively; 77.5% of OR staff had inadequate knowledge of prevention and control sources of fires. The study concluded that most of OR staff had inadequate knowledge of sources, controls, and prevention of fires, while 22.5% of them had adequate knowledge of prevention and control sources of fires. We recommended the implementation of training programs toward sources, controls, and prevention of fires or related workshops in their educational planning for OR staff of hospitals.

Keywords: knowledge, operation rooms staff, fires, prevention

Procedia PDF Downloads 83
9070 Russian Spatial Impersonal Sentence Models in Translation Perspective

Authors: Marina Fomina

Abstract:

The paper focuses on the category of semantic subject within the framework of a functional approach to linguistics. The semantic subject is related to similar notions such as the grammatical subject and the bearer of predicative feature. It is the multifaceted nature of the category of subject that 1) triggers a number of issues that, syntax-wise, remain to be dealt with (cf. semantic vs. syntactic functions / sentence parts vs. parts of speech issues, etc.); 2) results in a variety of approaches to the category of subject, such as formal grammatical, semantic/syntactic (functional), communicative approaches, etc. Many linguists consider the prototypical approach to the category of subject to be the most instrumental as it reveals the integrity of denotative and linguistic components of the conceptual category. This approach relates to subject as a source of non-passive predicative feature, an element of subject-predicate-object situation that can take on a variety of semantic roles, cf.: 1) an agent (He carefully surveyed the valley stretching before him), 2) an experiencer (I feel very bitter about this), 3) a recipient (I received this book as a gift), 4) a causee (The plane broke into three pieces), 5) a patient (This stove cleans easily), etc. It is believed that the variety of roles stems from the radial (prototypical) structure of the category with some members more central than others. Translation-wise, the most “treacherous” subject types are the peripheral ones. The paper 1) features a peripheral status of spatial impersonal sentence models such as U menia v ukhe zvenit (lit. I-Gen. in ear buzzes) within the category of semantic subject, 2) makes a structural and semantic analysis of the models, 3) focuses on their Russian-English translation patterns, 4) reveals non-prototypical features of subjects in the English equivalents.

Keywords: bearer of predicative feature, grammatical subject, impersonal sentence model, semantic subject

Procedia PDF Downloads 358
9069 Combining the Deep Neural Network with the K-Means for Traffic Accident Prediction

Authors: Celso L. Fernando, Toshio Yoshii, Takahiro Tsubota

Abstract:

Understanding the causes of a road accident and predicting their occurrence is key to preventing deaths and serious injuries from road accident events. Traditional statistical methods such as the Poisson and the Logistics regressions have been used to find the association of the traffic environmental factors with the accident occurred; recently, an artificial neural network, ANN, a computational technique that learns from historical data to make a more accurate prediction, has emerged. Although the ability to make accurate predictions, the ANN has difficulty dealing with highly unbalanced attribute patterns distribution in the training dataset; in such circumstances, the ANN treats the minority group as noise. However, in the real world data, the minority group is often the group of interest; e.g., in the road traffic accident data, the events of the accident are the group of interest. This study proposes a combination of the k-means with the ANN to improve the predictive ability of the neural network model by alleviating the effect of the unbalanced distribution of the attribute patterns in the training dataset. The results show that the proposed method improves the ability of the neural network to make a prediction on a highly unbalanced distributed attribute patterns dataset; however, on an even distributed attribute patterns dataset, the proposed method performs almost like a standard neural network.

Keywords: accident risks estimation, artificial neural network, deep learning, k-mean, road safety

Procedia PDF Downloads 141
9068 ZnO Nanoparticles as Photocatalysts: Synthesis, Characterization and Application

Authors: Pachari Chuenta, Suwat Nanan

Abstract:

ZnO nanostructures have been synthesized successfully in high yield via catalyst-free chemical precipitation technique by varying zinc source (either zinc nitrate or zinc acetate) and oxygen source (either oxalic acid or urea) without using any surfactant, organic solvent or capping agent. The ZnO nanostructures were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), UV-vis diffuse reflection spectroscopy (UV-vis DRS), and photoluminescence spectroscopy (PL). The FTIR peak in the range of 450-470 cm-1 corresponded to Zn-O stretching in ZnO structure. The synthesized ZnO samples showed well crystalized hexagonal wurtzite structure. SEM micrographs displayed spherical droplet of about 50-100 nm. The band gap of prepared ZnO was found to be 3.4-3.5 eV. The presence of PL peak at 468 nm was attributed to surface defect state. The photocatalytic activity of ZnO was studied by monitoring the photodegradation of reactive red (RR141) azo dye under ultraviolet (UV) light irradiation. Blank experiment was also separately carried out by irradiating the aqueous solution of the dye in absence of the photocatalyst. The initial concentration of the dye was fixed at 10 mgL-1. About 50 mg of ZnO photocatalyst was dispersed in 200 mL dye solution. The sample was collected at a regular time interval during the irradiation and then was analyzed after centrifugation. The concentration of the dye was determined by monitoring the absorbance at its maximum wavelength (λₘₐₓ) of 544 nm using UV-vis spectroscopic analysis technique. The sources of Zn and O played an important role on photocatalytic performance of the ZnO photocatalyst. ZnO nanoparticles which prepared by zinc acetate and oxalic acid at molar ratio of 1:1 showed high photocatalytic performance of about 97% toward photodegradation of reactive red azo dye (RR141) under UV light irradiation for only 60 min. This work demonstrates the promising potential of ZnO nanomaterials as photocatalysts for environmental remediation.

Keywords: azo dye, chemical precipitation, photocatalytic, ZnO

Procedia PDF Downloads 137
9067 Anti-Nutritional Factors, In-Vitro Trypsin, Chymotrypsin and Peptidase Multi Enzyme Protein Digestibility of Some Melon (Egusi) Seeds and Their Protein Isolates

Authors: Joan O. Ogundele, Aladesanmi A. Oshodi, Adekunle I. Amoo

Abstract:

Abstract In-vitro multi-enzyme protein digestibility (IVMPD) and some anti-nutritional factors (ANF) of five melon (egusi) seed flours (MSF) and their protein isolates (PI) were carried out. Their PI have potentials comparable to that of soya beans. It is important to know the IVMPD and ANF of these protein sources as to ensure their safety when adapted for use as alternate protein sources to substitute for cow milk, which is relatively expensive in Nigeria. Standard methods were used to produce PI of Citrullus colocynthis, Citrullus vulgaris, African Wine Kettle gourd (Lageneria siceraria I), Basket Ball gourd (Lagenaria siceraria II) and Bushel Giant Gourd (Lageneria siceraria III) seeds and to determine the ANF and IVMPD of the MSF and PI unheated and at 37oC. Multi-enzymes used were trypsin, chymotrypsin and peptidase. IVMPD of MSF ranged from (70.67±0.70) % (C. vulgaris) to (72.07± 1.79) % (L.siceraria I) while for their PI ranged from 74.33% (C.vulgaris) to 77.55% (L.siceraria III). IVMPD of the PI were higher than those of MSF. Heating increased IVMPD of MSF with average value of 79.40% and those of PI with average of 84.14%. ANF average in MSF are tannin (0.11mg/g), phytate (0.23%). Differences in IVMPD of MSF and their PI at different temperatures may arise from processing conditions that alter the release of amino acids from proteins by enzymatic processes. ANF in MSF were relatively low, but were found to be lower in the PI, therefor making the PI safer for human consumption as an alternate source of protein.

Keywords: Anti-nutrients, Enzymatic protein digestibility, Melon (egusi)., Protein Isolates.

Procedia PDF Downloads 102
9066 Effect of Different Level of Pomegranate Molasses on Performance, Egg Quality Trait, Serological and Hematological Parameters in Older Laying Hens

Authors: Ismail Bayram, Aamir Iqbal, E. Eren Gultepe, Cangir Uyarlar, Umit Ozcınar, I. Sadi Cetingul

Abstract:

The current study was planned with the objective to explore the potential of pomegranate molasses (PM) on performance, egg quality and blood parameters in older laying hens. A total of 240 Babcock white laying hens (52 weeks old) were divided into 5 groups (n=48) with 8 subgroups having 6 hens in each. Pomegranate molasses was added in the drinking water to experimental groups with 0 %, 0.1%, 0.25 %, 0.5%, and 1%, respectively during one month. In our results, egg weight values were remained the same in all pomegranate molasses supplemented groups except 1% group over control. However, feed consumption, egg production, feed conversion ratio (FCR), egg mass, egg yolk cholesterol, body weights, and water consumption remained unaffected (P > 0.05). During mid-study (15 Days) analyses, egg quality parameters such as Haugh unit, eggshell thickness, albumin index, yolk index, and egg yolk color were remained non-significant (P > 0.05) while after final (30 Days) egg analyses, only egg yolk color had positively (P < 0.05) increased in 0.5% group. Moreover, Haugh unit, eggshell thickness, and albumin index were not significantly (P > 0.05) affected by the supplementation of pomegranate molasses. Regarding serological parameters, pomegranate molasses did not show any positive effect on cholesterol, total protein, LDL, HDL, GGT, AST, ALT, and glucose level. Similarly, pomegranate molasses also showed non-significant (P > 0.05) results on different blood parameters such as HCT, RBC, MCV, MCH, MCHC, PLT, RDWC, MPV except hemoglobin level. Only hemoglobin level was increased in all experimental groups over control showing that pomegranate molasses can be used as an enhancer in animals with low hemoglobin level.

Keywords: pomegranate molasses, laying hen, egg yield, blood parameters

Procedia PDF Downloads 154
9065 Renal Transplant, Pregnancy, and Complications: A Literature Review

Authors: Sara Iqbal

Abstract:

Introduction:Renal transplant is increasingly one of the most popular transplants within the UK; with an aging population along with obesity epidemic we are witnessing increasing rates of diabetes – one of the commonest indications for renal transplant. However, the demand is far greater than supply. Many donors are provided by women of child-bearing age; however the long-term effects are still uncertain. Aim:Determine pregnancy outcomes and complications of women of child-bearing age following renal donation. Methods: A review of the current available literature was preformed using MEDLINE and EMBASE up to 2014. Search criteria included key terms such as pregnancy outcome post-renal donor, pregnancy outcomes and complications. Relevant articles were selected based on pure methodological medical research, after careful analysis, they were recorded within this review. Results: Out of 1141 women involved in transplant studies, 574 pregnancies reported having donated a single-renal donor prior to pregnancy. Of which a staggering miscarriage rate 32.4% (n=186) was reported, amongst this other complications included gestational hypertension of 10% (n=59) and gestational diabetes 2.3% (n=13). Other significantly noted complications included chronic hypertension, low-birth weights, and pregnancy-related death. Conclusions: After unilateral renal donor transplant, haemodynamics change along with pregnancy, predisposing women to developing several complications compared to pregnancies with no history any renal-donor transplant. Despite this, further investigation is required in order to accurately determine the safety of renal-donors in women of child-bearing age.

Keywords: renal transplant, pregnancy, complications, medical and health sciences

Procedia PDF Downloads 263
9064 Hierarchical Optimization of Composite Deployable Bridge Treadway Using Particle Swarm Optimization

Authors: Ashraf Osman

Abstract:

Effective deployable bridges that are characterized by an increased capacity to weight ratio are recently needed for post-disaster rapid mobility and military operations. In deployable bridging, replacing metals as the fabricating material with advanced composite laminates as lighter alternatives with higher strength is highly advantageous. This article presents a hierarchical optimization strategy of a composite bridge treadway considering maximum strength design and bridge weight minimization. Shape optimization of a generic deployable bridge beam cross-section is performed to achieve better stress distribution over the bridge treadway hull. The developed cross-section weight is minimized up to reserving the margins of safety of the deployable bridging code provisions. Hence, the strength of composite bridge plates is maximized through varying the plies orientation. Different loading cases are considered of a tracked vehicle patch load. The orthotropic plate properties of a composite sandwich core are used to simulate the bridge deck structural behavior. Whereas, the failure analysis is conducted using Tsai-Wu failure criterion. The naturally inspired particle swarm optimization technique is used in this study. The proposed technique efficiently reduced the weight to capacity ratio of the developed bridge beam.

Keywords: CFRP deployable bridges, disaster relief, military bridging, optimization of composites, particle swarm optimization

Procedia PDF Downloads 124
9063 Eco-Friendly Textiles: The Power of Natural Dyes

Authors: Bushra

Abstract:

This paper explores the historical significance, ecological benefits, and contemporary applications of natural dyes in textile dyeing, aiming to provide a comprehensive overview of their potential to contribute to a sustainable fashion industry while minimizing ecological footprints. This research explores the potential of natural dyes as a sustainable alternative to synthetic dyes in the textile industry, examining their historical context, sources, and environmental benefits. Natural dyes come from plants, animals, and minerals, including roots, leaves, bark, fruits, flowers, insects, and metal salts, used as mordants to fix dyes to fabrics. Natural dyeing involves extraction, mordanting, and dyeing techniques. Optimizing these processes can enhance the performance of natural dyes, making them viable for contemporary textile applications based on experimental research. Natural dyes offer eco-friendly benefits like biodegradability, non-toxicity, and resource renewables, reducing pollution, promoting biodiversity, and reducing reliance on petrochemicals. Natural dyes offer benefits but face challenges in color consistency, scalability, and performance, requiring industrial production to meet modern consumer standards for durability and colorfastness. Contemporary initiatives in the textile industry include fashion brands like Eileen Fisher and Patagonia incorporating natural dyes, artisans like India Flint's Botanical Alchemy promoting traditional dyeing techniques, and research projects like the European Union's Horizon 2020 program. Natural dyes offer a sustainable textile industry solution, reducing environmental impact and promoting harmony with nature. Research and innovation are paving the way for widespread adoption, transforming textile dyeing.

Keywords: historical significance, textile industry, natural dyes, sustainability

Procedia PDF Downloads 28
9062 Navigating Urban Childcare Challenges: Perspectives of Dhaka City Parents

Authors: Md. Shafiullah

Abstract:

This study delves into the evolving landscape of urban childcare in Bangladesh, focusing on the experiences and challenges faced by parents in Dhaka city. This paper argues that the traditional childcare arrangement of city families is inadequate to meet the development needs of children. The study aims to explore the childcare challenges faced by urban parents as they transition from traditional family-based childcare networks to alternative caregiving arrangements amidst urbanization, economic shifts, and social transformations. Utilizing a mixed-method research approach, combining quantitative surveys (n = 200) and four qualitative interviews, the research examines the parental viewpoints on childcare practices and the role of societal norms and values. The study finds childcare crises in both the family and daycare settings. In family care, caregiving suffers from the less availability of grandparents, a lack of skills of caregivers, and a lack of child interaction. As for the daycare, it is affected by the absence of appropriate policies, a lack of quality, health and safety concerns, affordability issues, and cultural concerns. Additionally, the study highlights inadequacies in childcare policies and regulatory frameworks, calling for comprehensive reforms to address the childcare vacuum in urban areas. By shifting the focus from developed to developing countries, this study contributes to the literature and suggests policy implications for Bangladesh and beyond.

Keywords: childcare, child development, childcare policy, daycare, Bangladesh

Procedia PDF Downloads 42
9061 Design Development and Qualification of a Magnetically Levitated Blower for C0₂ Scrubbing in Manned Space Missions

Authors: Larry Hawkins, Scott K. Sakakura, Michael J. Salopek

Abstract:

The Marshall Space Flight Center is designing and building a next-generation CO₂ removal system, the Four Bed Carbon Dioxide Scrubber (4BCO₂), which will use the International Space Station (ISS) as a testbed. The current ISS CO2 removal system has faced many challenges in both performance and reliability. Given that CO2 removal is an integral Environmental Control and Life Support System (ECLSS) subsystem, the 4BCO2 Scrubber has been designed to eliminate the shortfalls identified in the current ISS system. One of the key required upgrades was to improve the performance and reliability of the blower that provides the airflow through the CO₂ sorbent beds. A magnetically levitated blower, capable of higher airflow and pressure than the previous system, was developed to meet this need. The design and qualification testing of this next-generation blower are described here. The new blower features a high-efficiency permanent magnet motor, a five-axis, active magnetic bearing system, and a compact controller containing both a variable speed drive and a magnetic bearing controller. The blower uses a centrifugal impeller to pull air from the inlet port and drive it through an annular space around the motor and magnetic bearing components to the exhaust port. Technical challenges of the blower and controller development include survival of the blower system under launch random vibration loads, operation in microgravity, packaging under strict size and weight requirements, and successful operation during 4BCO₂ operational changeovers. An ANSYS structural dynamic model of the controller was used to predict response to the NASA defined random vibration spectrum and drive minor design changes. The simulation results are compared to measurements from qualification testing the controller on a vibration table. Predicted blower performance is compared to flow loop testing measurements. Dynamic response of the system to valve changeovers is presented and discussed using high bandwidth measurements from dynamic pressure probes, magnetic bearing position sensors, and actuator coil currents. The results presented in the paper show that the blower controller will survive launch vibration levels, the blower flow meets the requirements, and the magnetic bearings have adequate load capacity and control bandwidth to maintain the desired rotor position during the valve changeover transients.

Keywords: blower, carbon dioxide removal, environmental control and life support system, magnetic bearing, permanent magnet motor, validation testing, vibration

Procedia PDF Downloads 125
9060 The Acute Effects of a Warm-Up Including Different Dynamic Stretching on Hamstring Stiffness, Flexibility, and Strength

Authors: Che Hsiu Chen, Kuo Wei Tseng, Zih Jian Huang, Hon Wen Cheng

Abstract:

A typical warm-up contains both stretching exercises and jogging. The static stretching prior to training or competition may cause detrimental effects to athletic performance. However, it is unclear whether different types of dynamic stretching exercises had different acute effects on knee flexors stiffness, flexibility, and strength. The purpose of this study was to analyze the knee flexors stiffness, flexibility, and strength gains after dynamic straight leg raise (DSLR) and dynamic modified toe-touch (MTT) stretching. Sixteen healthy university active men (height 176.27 ± 4.03 cm; weight 72.27 ± 8.90 kg; age 22.09 ± 2.31 years). After 5 minutes (8km/h) of running subjects performed 2 randomly ordered stretching protocols: DSLR and MTT stretching protocols. There were a total of six, 30 seconds bouts of dynamic stretching (15 repetitions) with 30seconds rest between bouts. The outcome measures were maximal voluntary isokinetic concentric hamstring strength (60°/s), muscle flexibility test by passive straight leg raise (PSLR), active straight leg raise (ASLR), and muscle stiffness using ultrasound Acoustic Radiation Forced Impulse (ARFI) elastography before and immediately after stretching. The muscle stiffness and concentric strength decreased significantly (p < .05), the flexibility no significant change after DSLR protocol (p > .05). The concentric strength decreased significantly (p < .05), the flexibility and muscle stiffness no significant change after MTT protocol (p > .05), whereas no significant differences were found for the DSLR and MTT. Our findings suggest that dynamic stretching (30s x 6 bouts) resulted in change in muscle stiffness or may be induced slack in the musculotendinous unit thereby, reducing force production. Therefore, 30s x 6 bouts of dynamic stretching adversely affects efforts of hamstring muscle maximal concentric strength.

Keywords: sport injury, ultrasound, eccentric exercise, performance

Procedia PDF Downloads 271
9059 Design and Analysis of Semi-Active Isolation System in Low Frequency Excitation Region for Vehicle Seat to Reduce Discomfort

Authors: Andrea Tonoli, Nicola Amati, Maria Cavatorta, Reza Mirsanei, Behzad Mozaffari, Hamed Ahani, Akbar Karamihafshejani, Mohammad Ghazivakili, Mohammad Abuabiah

Abstract:

The vibrations transmitted to the drivers and passengers through vehicle seat seriously effect on the level of their attention, fatigue and physical health and reduce the comfort and efficiency of the occupants. Recently, some researchers have focused on vibrations at low excitation frequency(0.5-5 Hz) which are considered to be the main risk factors for lumbar part of the backbone but they were not applicable to A and B-segment cars regarding to the size and weight. A semi-active system with two symmetric negative stiffness structures (NSS) in parallel to a positive stiffness structure and actuators has been proposed to attenuate low frequency excitation and makes system flexible regarding to different weight of passengers which is applicable for A and B-Segment cars. Here, the 3 degree of freedom system is considered, dynamic equation clearly is presented, then simulated in MATLAB in order to analysis of performance of the system. The design procedure is derived so that the resonance peak of frequency–response curve shift to the left, the isolating range is increased and especially, the peak of the frequency–response curve is minimized. According to ISO standard different class of road profile as an input is applied to the system to evaluate the performance of the system. To evaluate comfort issues, we extract the RMS value of the vertical acceleration acting on the passenger's body. Then apply the band-pass filter, which takes into account the human sensitivity to acceleration. According to ISO, this weighted acceleration is lower than 0.315 m/s^2, so the ride is considered as comfortable.

Keywords: low frequency excitation, negative stiffness, seat vehicle, vibration isolation

Procedia PDF Downloads 420
9058 Noise Measurement and Awareness at Construction Site: A Case Study

Authors: Feiruz Ab'lah, Zarini Ismail, Mohamad Zaki Hassan, Siti Nadia Mohd Bakhori, Mohamad Azlan Suhot, Mohd Yusof Md. Daud, Shamsul Sarip

Abstract:

The construction industry is one of the major sectors in Malaysia. Apart from providing facilities, services, and goods it also offers employment opportunities to local and foreign workers. In fact, the construction workers are exposed to a hazardous level of noises that generated from various sources including excavators, bulldozers, concrete mixer, and piling machines. Previous studies indicated that the piling and concrete work was recorded as the main source that contributed to the highest level of noise among the others. Therefore, the aim of this study is to obtain the noise exposure during piling process and to determine the awareness of workers against noise pollution at the construction site. Initially, the reading of noise was obtained at construction site by using a digital sound level meter (SLM), and noise exposure to the workers was mapped. Readings were taken from four different distances; 5, 10, 15 and 20 meters from the piling machine. Furthermore, a set of questionnaire was also distributed to assess the knowledge regarding noise pollution at the construction site. The result showed that the mean noise level at 5m distance was more than 90 dB which exceeded the recommended level. Although the level of awareness regarding the effect of noise pollution is satisfactory, majority of workers (90%) still did not wear ear protecting device during work period. Therefore, the safety module guidelines related to noise pollution controls should be implemented to provide a safe working environment and prevent initial occupational hearing loss.

Keywords: construction, noise awareness, noise pollution, piling machine

Procedia PDF Downloads 365