Search results for: mass transfer coefficient
Commenced in January 2007
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Edition: International
Paper Count: 7792

Search results for: mass transfer coefficient

2722 Open Education Resources a Gateway for Accessing Hospitality and Tourism Learning Materials

Authors: Isiya Shinkafi Salihu

Abstract:

Open education resources (OER) are open learning materials in different formats, course content and context to support learning globally. This study investigated the level of awareness of Hospitality and Tourism OER among students in the Department of Tourism and Hotel Management in a University. Specifically, it investigated students’ awareness, use and accessibility of OER in learning. The research design method used was the quantitative approach, using an online questionnaire. The thesis research shows that respondents frequently use OER but with little knowledge of the content and context of the material. Most of the respondents’ have little knowledge about the concept even though they use it. Information and communication technologies are tools for information gathering, social networking and knowledge sharing and transfer. OER are open education materials accessible online such as curriculum, maps, course materials, and videos that users create, adapt, reuse for learning and research. Few of the respondents that used OER in learning faced some challenges such as high cost of data, poor connectivity and lack of proper guidance. The results suggest a lack of awareness of OER among students in the faculty of tourism and the need for support from the teachers in the utilization of OER. The thesis also reveals that some of the international students are accessing the internet as beginners in their studies which require guidance. The research, however, recommends that further studies should be conducted to other faculties.

Keywords: creative commons, open education resources, open licenses, information and communication technology

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2721 Multi-Criteria Decision-Making in Ranking Drinking Water Supply Options (Case Study: Tehran City)

Authors: Mohsen Akhlaghi, Tahereh Ebrahimi

Abstract:

Considering the increasing demand for water and limited resources, there is a possibility of a water crisis in the not-so-distant future. Therefore, to prevent this crisis, other options for drinking water supply should be examined. In this regard, the application of multi-criteria decision-making methods in various aspects of water resource management and planning has always been of great interest to researchers. In this report, six options for supplying drinking water to Tehran City were considered. Then, experts' opinions were collected through matrices and questionnaires, and using the TOPSIS method, which is one of the types of multi-criteria decision-making methods, they were calculated and analyzed. In the TOPSIS method, the options were ranked by calculating their proximity to the ideal (Ci). The closer the numerical value of Ci is to one, the more desirable the option is. Based on this, the option with the optimization pattern of water consumption, with Ci = 0.9787, is the best option among the proposed options for supplying drinking water to Tehran City. The other options, in order of priority, are rainwater harvesting, wastewater reuse, increasing current water supply sources, desalination and its transfer, and transferring water from freshwater sources between basins. In conclusion, the findings of this study highlight the importance of exploring alternative drinking water supply options and utilizing multi-criteria decision-making approaches to address the potential water crisis.

Keywords: multi-criteria decision, sustainable development, topsis, water supply

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2720 High Power Thermal Energy Storage for Industrial Applications Using Phase Change Material Slurry

Authors: Anastasia Stamatiou, Markus Odermatt, Dominic Leemann, Ludger J. Fischer, Joerg Worlitschek

Abstract:

The successful integration of thermal energy storage in industrial processes is expected to play an important role in the energy turnaround. Latent heat storage technologies can offer more compact thermal storage at a constant temperature level, in comparison to conventional, sensible thermal storage technologies. The focus of this study is the development of latent heat storage solutions based on the Phase Change Slurry (PCS) concept. Such systems promise higher energy densities both as refrigerants and as storage media while presenting better heat transfer characteristics than conventional latent heat storage technologies. This technology is expected to deliver high thermal power and high-temperature stability which makes it ideal for storage of process heat. An evaluation of important batch processes in industrial applications set the focus on materials with a melting point in the range of 55 - 90 °C. Aluminium ammonium sulfate dodecahydrate (NH₄Al(SO₄)₂·12H₂O) was chosen as the first interesting PCM for the next steps of this study. The ability of this material to produce slurries at the relevant temperatures was demonstrated in a continuous mode in a laboratory test-rig. Critical operational and design parameters were identified.

Keywords: esters, latent heat storage, phase change materials, thermal properties

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2719 Bioremediation of Sea Food Waste in Solid State Fermentation along with Production of Bioactive Agents

Authors: Rahul Warmoota, Aditya Bhardwaj, Steffy Angural, Monika Rana, Sunena Jassal, Neena Puri, Naveen Gupta

Abstract:

Seafood processing generates large volumes of waste products such as skin, heads, tails, shells, scales, backbones, etc. Pollution due to conventional methods of seafood waste disposal causes negative implications on the environment, aquatic life, and human health. Moreover, these waste products can be used for the production of high-value products which are still untapped due to inappropriate management. Paenibacillus sp. AD is known to act on chitinolytic and proteinaceous waste and was explored for its potential to degrade various types of seafood waste in solid-state fermentation. Effective degradation of seafood waste generated from a variety of sources such as fish scales, crab shells, prawn shells, and a mixture of such wastes was observed. 30 to 40 percent degradation in terms of decrease in the mass was achieved. Along with the degradation, chitinolytic and proteolytic enzymes were produced, which can have various biotechnological applications. Apart from this, value-added products such as chitin oligosaccharides and peptides of various degrees of polymerization were also produced, which can be used for various therapeutic purposes. Results indicated that Paenibacillus sp. AD can be used for the development of a process for the infield degradation of seafood waste.

Keywords: chitin, chitin-oligosaccharides, chitinase, protease, biodegradation, crab shells, prawn shells, fish scales

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2718 Psychosocial Determinants of School Violent Behavior and the Efficacy of Covert Sensitization in Combination with Systematic approach Therapy among Male Students in Lagos Metropolis: Implications for Student Counselors

Authors: Fidel O. Okopi, Aminu Kazeem Ibrahim

Abstract:

The study investigated psychosocial determinants ‘attitudes and self-esteem’ of school violent behaviors and the efficacy of covert sensitization therapy in combination with systematic approach therapy among male students in Lagos metropolis. Ex-post facto experimental research design was adopted for the study. The samples consisted of 39 school violent behavior students identified through the School Disciplinary Record Books and another 39 non-school violent behavior students identified through randomization. The two groups were from four randomly selected Public Senior Secondary Schools. School Violent Behavior Attitudes Scale (SVBAS) and School Violent Behavior Self-Esteem Scale (SVBSES) were used to collect data for the study. Face and Content validity with the Reliability coefficient of 0.772 for SVBAS and 0.813 for SVBSES were obtained. The results showed that the attitude of school violent behavior students do not significantly differ from that of school non-violent behavior students; the self-esteem of school violent behavior students differs significantly from that of school non-violent behavior students and that Covert Sensitization therapy in combination with Systematic Approach therapy were effective in modifying the self-esteem and attitude of school violent behavior students as surf iced in the pre-test and post-test analysis of school violent behavior students’ responses. The School counselors can modify male school violent behaviors that are traced to attitude and self-esteem with Covert Sensitization therapy in combination with Systematic Approach therapy in metropolitan areas.

Keywords: psychosocial determinants, violent behavior, covert sensitization therapy, systematic approach therapy

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2717 Optimizing the Readability of Orthopaedic Trauma Patient Education Materials Using ChatGPT-4

Authors: Oscar Covarrubias, Diane Ghanem, Christopher Murdock, Babar Shafiq

Abstract:

Introduction: ChatGPT is an advanced language AI tool designed to understand and generate human-like text. The aim of this study is to assess the ability of ChatGPT-4 to re-write orthopaedic trauma patient education materials at the recommended 6th-grade level. Methods: Two independent reviewers accessed ChatGPT-4 (chat.openai.com) and gave identical instructions to simplify the readability of provided text to a 6th-grade level. All trauma-related articles by the Orthopaedic Trauma Association (OTA) and American Academy of Orthopaedic Surgeons (AAOS) were sequentially provided. The academic grade level was determined using the Flesh-Kincaid Grade Level (FKGL) and Flesch Reading Ease (FRE). Paired t-tests and Wilcox-rank sum tests were used to compare the FKGL and FRE between the ChatGPT-4 revised and original text. Inter-rater correlation coefficient (ICC) was used to assess variability in ChatGPT-4 generated text between the two reviewers. Results: ChatGPT-4 significantly reduced FKGL and increased FRE scores in the OTA (FKGL: 5.7±0.5 compared to the original 8.2±1.1, FRE: 76.4±5.7 compared to the original 65.5±6.6, p < 0.001) and AAOS articles (FKGL: 5.8±0.8 compared to the original 8.9±0.8, FRE: 76±5.5 compared to the original 56.7±5.9, p < 0.001). On average, 14.6% of OTA and 28.6% of AAOS articles required at least two revisions by ChatGPT-4 to achieve a 6th-grade reading level. ICC demonstrated poor reliability for FKGL (OTA 0.24, AAOS 0.45) and moderate reliability for FRE (OTA 0.61, AAOS 0.73). Conclusion: This study provides a novel, simple and efficient method using language AI to optimize the readability of patient education content which may only require the surgeon’s final proofreading. This method would likely be as effective for other medical specialties.

Keywords: artificial intelligence, AI, chatGPT, patient education, readability, trauma education

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2716 Underdiagnosis of Supraclavicular Brachial Plexus Metastasis in the Shadow of Cervical Disc Herniation: Insights from a Lung Cancer Case Study

Authors: Eunhwa Jun

Abstract:

This case report describes the misdiagnosis of a patient who presented with right arm pain as cervical disc herniation. The patient had several underlying conditions, including hypertension, diabetes mellitus, liver cirrhosis, a history of lung cancer with left lower lobe lobectomy, and adjuvant chemoradiotherapy. An external cervical spine MRI revealed central protruding discs at the C4-5-6-7 levels. Despite treatment with medication and epidural blocks, the patient's pain persisted. A C-RACZ procedure was planned, but the patient's pain had worsened before admission. Using ultrasound, a brachial plexus block was attempted, but the brachial plexus eluded clear visualization, hinting at underlying neurological complexities. Chest CT revealed a new, large soft tissue mass in the right supraclavicular region with adjacent right axillary lymphadenopathy, leading to the diagnosis of metastatic squamous cell carcinoma. Palliative radiation therapy and chemotherapy were initiated as part of the treatment plan, and the patient's pain score decreased to 3 out of 10 on the Numeric Rating Scale (NRS), revealing the pain was due to metastatic lung cancer.

Keywords: supraclavicula brachial plexus metastasis, cervical disc herniation, brachial plexus block, metastatic lung cancer

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2715 Analyzing Migration Patterns Using Public Disorder Event Data

Authors: Marie E. Docken

Abstract:

At some point in the lifecycle of a country, patterns of political and social unrest of varying degrees are observed. Events involving public disorder or civil disobedience may produce effects that range a wide spectrum of varying outcomes, depending on the level of unrest. Many previous studies, primarily theoretical in nature, have attempted to measure public disorder in answering why or how it occurs in society by examining causal factors or underlying issues in the social or political position of a population. The main objective in doing so is to understand how these activities evolve or seek some predictive capability for the events. In contrast, this research involves the fusion of analytics and social studies to provide more knowledge of the public disorder and civil disobedience intensity in populations. With a greater understanding of the magnitude of these events, it is believed that we may learn how they relate to extreme actions such as mass migration or violence. Upon establishing a model for measuring civil unrest based upon empirical data, a case study on various Latin American countries is performed. Interpretations of historical events are combined with analytical results to provide insights regarding the magnitude and effect of social and political activism.

Keywords: public disorder, civil disobedience, Latin America, metrics, data analysis

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2714 Prediction of California Bearing Ratio of a Black Cotton Soil Stabilized with Waste Glass and Eggshell Powder using Artificial Neural Network

Authors: Biruhi Tesfaye, Avinash M. Potdar

Abstract:

The laboratory test process to determine the California bearing ratio (CBR) of black cotton soils is not only overpriced but also time-consuming as well. Hence advanced prediction of CBR plays a significant role as it is applicable In pavement design. The prediction of CBR of treated soil was executed by Artificial Neural Networks (ANNs) which is a Computational tool based on the properties of the biological neural system. To observe CBR values, combined eggshell and waste glass was added to soil as 4, 8, 12, and 16 % of the weights of the soil samples. Accordingly, the laboratory related tests were conducted to get the required best model. The maximum CBR value found at 5.8 at 8 % of eggshell waste glass powder addition. The model was developed using CBR as an output layer variable. CBR was considered as a function of the joint effect of liquid limit, plastic limit, and plastic index, optimum moisture content and maximum dry density. The best model that has been found was ANN with 5, 6 and 1 neurons in the input, hidden and output layer correspondingly. The performance of selected ANN has been 0.99996, 4.44E-05, 0.00353 and 0.0067 which are correlation coefficient (R), mean square error (MSE), mean absolute error (MAE) and root mean square error (RMSE) respectively. The research presented or summarized above throws light on future scope on stabilization with waste glass combined with different percentages of eggshell that leads to the economical design of CBR acceptable to pavement sub-base or base, as desired.

Keywords: CBR, artificial neural network, liquid limit, plastic limit, maximum dry density, OMC

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2713 Classification of Traffic Complex Acoustic Space

Authors: Bin Wang, Jian Kang

Abstract:

After years of development, the study of soundscape has been refined to the types of urban space and building. Traffic complex takes traffic function as the core, with obvious design features of architectural space combination and traffic streamline. The acoustic environment is strongly characterized by function, space, material, user and other factors. Traffic complex integrates various functions of business, accommodation, entertainment and so on. It has various forms, complex and varied experiences, and its acoustic environment is turned rich and interesting with distribution and coordination of various functions, division and unification of the mass, separation and organization of different space and the cross and the integration of multiple traffic flow. In this study, it made field recordings of each space of various traffic complex, and extracted and analyzed different acoustic elements, including changes in sound pressure, frequency distribution, steady sound source, sound source information and other aspects, to make cluster analysis of each independent traffic complex buildings. It divided complicated traffic complex building space into several typical sound space from acoustic environment perspective, mainly including stable sound space, high-pressure sound space, rhythm sound space and upheaval sound space. This classification can further deepen the study of subjective evaluation and control of the acoustic environment of traffic complex.

Keywords: soundscape, traffic complex, cluster analysis, classification

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2712 Metastatic Ovarian Tumor Discovered Accidentally during Cesarean Section in a 34 Year Old Woman: A Case Report

Authors: Ghada E. Esheba, Ghufran Kheshaifaty, Kholoud Al-Harbi, Wafa'a Al-Harbi, Ala'a Al-Orabi, Moayad Turkistani

Abstract:

Krukenberg tumor is a rare metastatic ovarian carcinoma that usually occurs in female between 30 - 40 year old and rarely seen after menopause. Stomach is the most common primary site. Histopathological features of krukenberg tumors appear as diffuse stromal proliferation, mucus-production, and numerous signet-cells and these tumors spread mostly by lymphatic route. Treatment and prognostic factors are not well established. This study describes a 34 year old female with a unilateral ovarian mass discovered accidentally during cesarean section delivery and it was misdiagnosed as luteoma of pregnancy, but histopathological examination showed a diffuse infiltration of the ovary and omentum by signet ring cells. These findings were not correlated with luteoma of pregnancy or any other types of primary ovarian tumors like surface epithelial tumor, sex cord stromal tumor or germ cell tumor. However, after the analysis of immunohistochemical results (negative CK7, positive CK20 and CDX-2), the finding was the diagnostic of metastatic krukenberg tumor. Two weeks later, the patient was evaluated and a large gastric tumor was found in her stomach and she underwent gastrectomy.

Keywords: CK7, CK20, CDX-2, Krukenburg tumor, metastatic ovarian tumor

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2711 The Distribution of Prevalent Supplemental Nutrition Assistance Program-Authorized Food Store Formats Differ by U.S. Region and Rurality: Implications for Food Access and Obesity Linkages

Authors: Bailey Houghtaling, Elena Serrano, Vivica Kraak, Samantha Harden, George Davis, Sarah Misyak

Abstract:

United States (U.S.) Department of Agriculture Supplemental Nutrition Assistance Program (SNAP) participants are low-income Americans receiving federal dollars for supplemental food and beverage purchases. Participants use a variety of (traditional/non-traditional) SNAP-authorized stores for household dietary purchases - also representing food access points for all Americans. Importantly consumers' food and beverage purchases from non-traditional store formats tend to be higher in saturated fats, added sugars, and sodium when compared to purchases from traditional (e.g., grocery/supermarket) formats. Overconsumption of energy-dense and low-nutrient food and beverage products contribute to high obesity rates and adverse health outcomes that differ in severity among urban/rural U.S. locations and high/low-income populations. Little is known about the SNAP-authorized food store format landscape nationally, regionally, or by urban-rural status, as traditional formats are currently used as the gold standard in food access research. This research utilized publicly available U.S. databases to fill this large literature gap and to provide insight into modes of food access for vulnerable U.S. populations: (1) SNAP Retailer Locator which provides a list of all authorized food stores in the U.S., and; (2) Rural-Urban Continuum Codes (RUCC) that categorize U.S. counties as urban (RUCC 1-3) or rural (RUCC 4-9). Frequencies were determined for the highest occurring food store formats nationally and within two regionally diverse U.S. states – Virginia in the east and California in the west. Store format codes were assigned (e.g., grocery, drug, convenience, mass merchandiser, supercenter, dollar, club, or other). RUCC was applied to investigate state-level differences in urbanity-rurality regarding prevalent food store formats and Chi Square test of independence was used to determine if food store format distributions significantly (p < 0.05) differed by region or rurality. The resulting research sample that represented highly prevalent SNAP-authorized food stores nationally included 41.25% of all SNAP stores in the U.S. (N=257,839), comprised primarily of convenience formats (31.94%) followed by dollar (25.58%), drug (19.24%), traditional (10.87%), supercenter (6.85%), mass merchandiser (1.62%), non-food store or restaurant (1.81%), and club formats (1.09%). Results also indicated that the distribution of prevalent SNAP-authorized formats significantly differed by state. California had a lower proportion of traditional (9.96%) and a higher proportion of drug (28.92%) formats than Virginia- 11.55% and 19.97%, respectively (p < 0.001). Virginia also had a higher proportion of dollar formats (26.11%) when compared to California (10.64%) (p < 0.001). Significant differences were also observed for rurality variables (p < 0.001). Prominently, rural Virginia had a significantly higher proportion of dollar formats (41.71%) when compared to urban Virginia (21.78%) and rural California (21.21%). Non-traditional SNAP-authorized formats are highly prevalent and significantly differ in distribution by U.S. region and rurality. The largest proportional difference was observed for dollar formats where the least nutritious consumer purchases are documented in the literature. Researchers/practitioners should investigate non-traditional food stores at the local level using these research findings and similar applied methodologies to determine how access to various store formats impact obesity prevalence. For example, dollar stores may be prime targets for interventions to enhance nutritious consumer purchases in rural Virginia while targeting drug formats in California may be more appropriate.

Keywords: food access, food store format, nutrition interventions, SNAP consumers

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2710 Effectiveness of Public Speaking Extracurricular in Gontor in Raising Leaders of the Advanced Global World's Needs

Authors: Ummi Sholihah Pertiwi Abidin, Khusnul Hajar Nuansari

Abstract:

Human resource is one of the most important components that can not be separated from communication fields, either in a large community like a mass or narrow ones such as an institution, office, group and even family. Human resource is an asset which is often used as a tool to achieve certain goals. Therefore, development of human resources is essential for improving skills and character of a person especially at the time that has entered globalization era. People are required to be able to compete both in the local and international arena, no matter what. This paper raised topic related to human resource development solution by a unique educational leadership and communication skill improvement through a linguistic approach. Here the authors want to go by form of public speaking method applied in Modern Islamic Boarding School Darussalam Gontor as the extracurricular activity that is using three languages, they are: Indonesian as the mother language or the nation language of the students, Arabic and English as the second language and Gontor’s mean to supply its students to be able to conquer the globalization needs. This implementation produced the establishment of great leaders through confidence growing to speak in public by adjusting the listener context. In linguistic term, it will help enhancing verbal and nonverbal communication skills and so forth in owning a lot of vocabulary.

Keywords: public speaking, Gontor, language, leadership

Procedia PDF Downloads 255
2709 Prediction of Boundary Shear Stress with Flood Plains Enlargements

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

Abstract:

The river is our main source of water which is a form of open channel flow and the flow in the open channel provides with many complex phenomena of sciences that need to be tackled such as the critical flow conditions, boundary shear stress, and depth-averaged velocity. The development of society, more or less solely depends upon the flow of rivers. The rivers are major sources of many sediments and specific ingredients which are much essential for human beings. During floods, part of a river is carried by the simple main channel and rest is carried by flood plains. For such compound asymmetric channels, the flow structure becomes complicated due to momentum exchange between the main channel and adjoining flood plains. Distribution of boundary shear in subsections provides us with the concept of momentum transfer between the interface of the main channel and the flood plains. Experimentally, to get better data with accurate results are very complex because of the complexity of the problem. Hence, CES software has been used to tackle the complex processes to determine the shear stresses at different sections of an open channel having asymmetric flood plains on both sides of the main channel, and the results are compared with the symmetric flood plains for various geometrical shapes and flow conditions. Error analysis is also performed to know the degree of accuracy of the model implemented.

Keywords: depth average velocity, non prismatic compound channel, relative flow depth, velocity distribution

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2708 Numerical Study of Bubbling Fluidized Beds Operating at Sub-atmospheric Conditions

Authors: Lanka Dinushke Weerasiri, Subrat Das, Daniel Fabijanic, William Yang

Abstract:

Fluidization at vacuum pressure has been a topic that is of growing research interest. Several industrial applications (such as drying, extractive metallurgy, and chemical vapor deposition (CVD)) can potentially take advantage of vacuum pressure fluidization. Particularly, the fine chemical industry requires processing under safe conditions for thermolabile substances, and reduced pressure fluidized beds offer an alternative. Fluidized beds under vacuum conditions provide optimal conditions for treatment of granular materials where the reduced gas pressure maintains an operational environment outside of flammability conditions. The fluidization at low-pressure is markedly different from the usual gas flow patterns of atmospheric fluidization. The different flow regimes can be characterized by the dimensionless Knudsen number. Nevertheless, hydrodynamics of bubbling vacuum fluidized beds has not been investigated to author’s best knowledge. In this work, the two-fluid numerical method was used to determine the impact of reduced pressure on the fundamental properties of a fluidized bed. The slip flow model implemented by Ansys Fluent User Defined Functions (UDF) was used to determine the interphase momentum exchange coefficient. A wide range of operating pressures was investigated (1.01, 0.5, 0.25, 0.1 and 0.03 Bar). The gas was supplied by a uniform inlet at 1.5Umf and 2Umf. The predicted minimum fluidization velocity (Umf) shows excellent agreement with the experimental data. The results show that the operating pressure has a notable impact on the bed properties and its hydrodynamics. Furthermore, it also shows that the existing Gorosko correlation that predicts bed expansion is not applicable under reduced pressure conditions.

Keywords: computational fluid dynamics, fluidized bed, gas-solid flow, vacuum pressure, slip flow, minimum fluidization velocity

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2707 The Effect of Eight-Week Medium Intensity Interval Training and Curcumin Intake on ICMA-1 and VCAM-1 Levels in Menopausal Fat Rats

Authors: Abdolrasoul Daneshjoo, Fatemeh Akbari Ghara

Abstract:

Background and Purpose: Obesity is an increasing factor in cardiovascular disease and serum levels of cellular adhesion molecule. It plays an important role in predicting risk for coronary artery disease. The purpose of this research was to study the effect of eight weeks moderate intensity interval training and curcumin intake on ICAM-1 & VCAM-1 levels of menopausal fat rats. Materials and methods: in this study, 28 Wistar Menopausal fat rats aged 6-8 weeks with an average weight of 250-300 (gr) were randomly divided into four groups: control, curcumin supplement, moderate intensity interval training and moderate intensity interval training + curcumin supplement. (7 rats each group). The training program was planned as 8 weeks and 3 sessions per week. Each session consisted of 10 one-min sets with 50 percent intensity and the 2-minutes interval between sets in the first week. Subjects started with 14 meters per minute, and 2 (m/min) was added to increase their speed weekly until the speed of 28 (m/min) in the 8th week. Blood samples were taken 48 hours after the last training session, and ICAM-1 A and VCAM-1 levels were measured. SPSS software, one-way analysis of variance (ANOVA) and Pearson correlation coefficient were used to assess the results. Results: The results showed that eight weeks of training and taking curcumin had significant effects on ICAM-1 levels of the rats (p ≤ 0.05). However, it had no significant effect on VCAM-1 levels in menopausal obese rates (p ≥ 0.05). There was no significant correlation between the levels of ICAM-1 and VCAM-1 in eight weeks training and taking curcumin. Conclusion: Implementation of moderate intensity interval training and the use of curcumin decreased ICAM-1 significantly.

Keywords: curcumin, interval training , ICMA, VCAM

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2706 Electrophoretic Deposition of p-Type Bi2Te3 for Thermoelectric Applications

Authors: Tahereh Talebi, Reza Ghomashchi, Pejman Talemi, Sima Aminorroaya

Abstract:

Electrophoretic deposition (EPD) of p-type Bi2Te3 material has been accomplished, and a high quality crack-free thick film has been achieved for thermoelectric (TE) applications. TE generators (TEG) can convert waste heat into electricity, which can potentially solve global warming problems. However, TEG is expensive due to the high cost of materials, as well as the complex and expensive manufacturing process. EPD is a simple and cost-effective method which has been used recently for advanced applications. In EPD, when a DC electric field is applied to the charged powder particles suspended in a suspension, they are attracted and deposited on the substrate with the opposite charge. In this study, it has been shown that it is possible to prepare a TE film using the EPD method and potentially achieve high TE properties at low cost. The relationship between the deposition weight and the EPD-related process parameters, such as applied voltage and time, has been investigated and a linear dependence has been observed, which is in good agreement with the theoretical principles of EPD. A stable EPD suspension of p-type Bi2Te3 was prepared in a mixture of acetone-ethanol with triethanolamine as a stabilizer. To achieve a high quality homogenous film on a copper substrate, the optimum voltage and time of the EPD process was investigated. The morphology and microstructures of the green deposited films have been investigated using a scanning electron microscope (SEM). The green Bi2Te3 films have shown good adhesion to the substrate. In summary, this study has shown that not only EPD of p-type Bi2Te3 material is possible, but its thick film is of high quality for TE applications.

Keywords: electrical conductivity, electrophoretic deposition, mechanical property, p-type Bi2Te3, Seebeck coefficient, thermoelectric materials, thick films

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2705 Computational Fluid Dynamics Analysis of a Biomass Burner Gas Chamber in OpenFOAM

Authors: Óscar Alfonso Gómez Sepúlveda, Julián Ernesto Jaramillo, Diego Camilo Durán

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The global climate crisis has affected different aspects of human life, and in an effort to reverse the effects generated, we seek to optimize and improve the equipment and plants that produce high emissions of CO₂, being possible to achieve this through numerical simulations. These equipments include biomass combustion chambers. The objective of this research is to visualize the thermal behavior of a gas chamber that is used in the process of obtaining vegetable extracts. The simulation is carried out with OpenFOAM taking into account the conservation of energy, turbulence, and radiation; for the purposes of the simulation, combustion is omitted and replaced by heat generation. Within the results, the streamlines generated by the primary and secondary flows are analyzed in order to visualize whether they generate the expected effect, and the energy is used to the maximum. The inclusion of radiation seeks to compare its influence and also simplify the computational times to perform mesh analysis. An analysis is carried out with simplified geometries and with experimental data to corroborate the selection of the models to be used, and it is obtained that for turbulence, the appropriate one is the standard k - w. As a means of verification, a general energy balance is made and compared with the results of the numerical analysis, where the error is 1.67%, which is considered acceptable. From the approach to improvement options, it was found that with the implementation of fins, heat can be increased by up to 7.3%.

Keywords: CFD analysis, biomass, heat transfer, radiation, OpenFOAM

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2704 Study of the Adhesive Bond Effect on Electro-Mechanical Behaviour of Coupled Piezo Structural System

Authors: Rahul S. Raj

Abstract:

Electro-mechanical impedance technique is a recently developed non-destructive method for structural health monitoring. This system comprises of piezo electric patch, bonded to the structure using an adhesive/epoxy and electrically excited to determine the health of the component. The subjected electric field actuates the PZT patch harmonically and imparts a force on the host structure. The structural response thus produced by the host component is in the form of peaks and valleys which further shows the admittance signatures of the structure for the given excitation frequency. Adhesives have the capability to change the structural signatures, in EMI technique, by transforming conductance and susceptance signatures. The static approximation provide a justifiable result where adhesive bond lines are thin and stiff. The epoxy adhesive bonds limits design flexibility due to poor bond strengths, hence to enhance the performance of the joints, a new technique is developed for joining PZT, i.e. the alloy bonding technique. It is a metallic joining compound which contains many active elements including Titanium, that reacts with the tenacious surface films of the ceramic and composites to create excellent bonds. This alloy-based bonding technique will be used for better strain interaction and rigorous stress transfer between PZT patch and the host structure.

Keywords: EMI technique, conductance, susceptance, admittance, alloy bonding

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2703 Effect of the Concrete Cover on the Bond Strength of the FRP Wrapped and Non-Wrapped Reinforced Concrete Beam with Lap Splice under Uni-Direction Cyclic Loading

Authors: Rayed Alyousef, Tim Topper, Adil Al-Mayah

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Many of the reinforced concrete structures subject to cyclic load constructed before the modern bond and fatigue design code. One of the main issue face on exists structure is the bond strength of the longitudinal steel bar and the surrounding concrete. A lap splice is a common connection method to transfer the force between the steel rebar in a reinforced concrete member. Usually, the lap splice is the weak connection on the bond strength. Fatigue flexural loading imposes severe demands on the strength and ductility of the lap splice region in reinforced concrete structures and can lead to a brittle and sudden failure of the member. This paper investigates the effect of different concrete covers on the fatigue bond strength of reinforcing concrete beams containing a lap splice under a fatigue loads. It includes tests of thirty-seven beams divided into three groups. Each group has beams with 30 mm and 50 mm clear side and bottom concrete covers. The variables that were addressed where the concrete cover, the presence or absence of CFRP or GFRP sheet wrapping, the type of loading (monotonic or fatigue) and the fatigue load ranges. The test results showed that an increase in the concrete cover led to an increase in the bond strength under both monotonic and fatigue loading for both the unwrapped and wrapped beams. Also, the FRP sheets increased both the fatigue strength and the ductility for both the 30 mm and the 50 mm concrete covers.

Keywords: bond strength, fatigue, Lap splice, FRp wrapping

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2702 Particle and Photon Trajectories near the Black Hole Immersed in the Nonstatic Cosmological Background

Authors: Elena M. Kopteva, Pavlina Jaluvkova, Zdenek Stuchlik

Abstract:

The question of constructing a consistent model of the cosmological black hole remains to be unsolved and still attracts the interest of cosmologists as far as it is important in a wide set of research problems including the problem of the black hole horizon dynamics, the problem of interplay between cosmological expansion and local gravity, the problem of structure formation in the early universe etc. In this work, the model of the cosmological black hole is built on the basis of the exact solution of the Einstein equations for the spherically symmetric inhomogeneous dust distribution in the approach of the mass function use. Possible trajectories for massive particles and photons near the black hole immersed in the nonstatic dust cosmological background are investigated in frame of the obtained model. The reference system of distant galaxy comoving to cosmological expansion combined with curvature coordinates is used, so that the resulting metric becomes nondiagonal and involves both proper ‘cosmological’ time and curvature spatial coordinates. For this metric the geodesic equations are analyzed for the test particles and photons, and the respective trajectories are built.

Keywords: exact solutions for Einstein equations, Lemaitre-Tolman-Bondi solution, cosmological black holes, particle and photon trajectories

Procedia PDF Downloads 341
2701 Permanent Deformation Resistance of Asphalt Mixtures with Red Mud as a Filler

Authors: Liseane Padilha Thives, Mayara S. S. Lima, João Victor Staub De Melo, Glicério Trichês

Abstract:

Red mud is a waste resulting from the processing of bauxite to alumina, the raw material of the production of aluminum. The large quantity of red mud generated and inadequately disposed in the environment has motivated researchers to develop methods for reinsertion of this waste into the productive cycle. This work aims to evaluate the resistance to permanent deformation of dense asphalt mixtures with red mud filler. The red mud was characterized by tests of X-ray diffraction, fluorescence, specific mass, laser granulometry, pH and scanning electron microscopy. For the analysis of the influence of the quantity of red mud in the mechanical performance of asphalt mixtures, a total filler content of 7% was established. Asphalt mixtures with 3%, 5% and 7% red mud were produced. A conventional mixture with 7% stone powder filler was used as reference. The asphalt mixtures were evaluated for performance to permanent deformation in the French Rutting Tester (FRT) traffic simulator. The mixture with 5% red mud presented greater resistance to permanent deformation with rutting depth at 30,000 cycles of 3.50%. The asphalt mixtures with red mud presented better performance, with reduction of the rutting of 12.63 to 42.62% in relation to the reference mixture. This study confirmed the viability of reinserting the red mud in the production chain and possible usage in the construction industry. The red mud as filler in asphalt mixtures is a reuse option of this waste and mitigation of the disposal problems, as well as being an environmentally friendly alternative.

Keywords: asphalt mixtures, permanent deformation, red mud, pavements

Procedia PDF Downloads 292
2700 Translation and Validation of the Pediatric Quality of Life Inventory for Children in Pakistani Context

Authors: Nazia Mustafa, Aneela Maqsood

Abstract:

Pediatric Quality of Life Inventory is the most widely used instrument for assessing children and adolescent health-related quality of life and has shown excellent markers of reliability and validity. The current study was carried out with the objectives of translation and cross-language validation along with the determination of factor Structure and psychometric properties of the Urdu version. It was administered on 154 Primary School Children with age range 10 to12 years (M= 10.86, S.D = 0.62); including boys (n=92) and girls (n = 62). The sample was recruited from two randomly selected schools from the Rawalpindi district of Pakistan. Results of the pilot phase revealed that the instrument had good reliability (Urdu Version α = 0.798; English Version α = 0.795) as well as test-retest correlation coefficients over a period of 15 days (r = 0.85). Exploratory factor analysis (EFA) resulted in three factorial structures; Social/School Functioning (k = 8), Psychological Functioning (k = 7) and Physical Functioning (k = 6) considered suitable for our sample instead of four factors. Bartlett's test of sphericity showed inter-correlation between variables. However, factor loadings for items 22 and 23 of the School Functioning subscale were problematic. The model was fit to the data after their removal with Cronbach’s Alpha Reliability coefficient of the scale (k = 21) as 0.87 and for subscales as 0.75, 0.77 and 0.73 for Social/School Scale, Psychological subscale and Physical subscale, respectively. These results supported the feasibility and reliability of the Urdu version of the Pediatric Quality of Life Inventory as a reliable and effective tool for the measurement of quality of life among Pediatrics Pakistani population.

Keywords: primary school children, paediatric quality of life, exploratory factor analysis, Pakistan

Procedia PDF Downloads 137
2699 Spectroscopic Studies on Solubilization of Polycyclic Aromatic Hydrocarbons in Structurally Different Gemini Surfactants

Authors: Toshikee Yadav, Deepti Tikariha, Jyotsna Lakra, Kallol K. Ghosh

Abstract:

Polycyclic aromatic hydrocarbons (PAHs) are potent atmospheric pollutants that consist of two or more benzene rings. PAHs have low solubility in water. Their slow dissolution can contaminate large amounts of ground water for long period. They are hydrophobic, non-polar and neutral in nature and are known to have potential mutagenic or carcinogenic activity. In current scenario their removal from the environment, water and soil is still a great challenge and scientists worldwide are engaged to invent and design novel separation technology and decontaminating systems. Various physical, chemical, biological and their combined technologies have been applied to remediate organic-contaminated soils and groundwater. Surfactants play a vital role in the solubilization of these hydrophobic organic compounds. In the present investigation Solubilization capabilities of structurally different gemini surfactants i.e. butanediyl-1,4-bis(dimethyldodecylammonium bromide) (C12-4-C12,2Br−), 2-butanol-1,4-bis (dimethyldodecylammonium bromide) (C12-4(OH)-C12,2Br−), 2,3-butanediol-1,4-bis (dimethyldodecylammonium bromide) (C12-4(OH)2-C12,2Br−) for three polycyclic aromatic hydrocarbons (PAHs); phenanthrene (Phe),fluorene (Fluo) and acenaphthene (Ace) have been studied spectrophotometrically at 300 K. The result showed that the solubility of PAHs increases linearly with increasing surfactant concentration, as an implication of association between the PAHs and micelles. Molar solubilization ratio (MSR), micelle–water partition coefficient (Km) and Gibb's free energy of solubilization (ΔG°s) for PAHs have been determined in aqueous medium. (C12-4(OH)2-C12,2Br−) shows the higher solubilization for all PAHs. Findings of the present investigation may be useful to understand the role of appropriate surfactant system for the solubilization of toxic hydrophobic organic compounds.

Keywords: gemini surfactant, molar solubilization ratio, polycyclic aromatic hydrocarbon, solubilization

Procedia PDF Downloads 447
2698 Purification, Biochemical Characterization and Application of an Extracellular Alkaline Keratinase Produced by Aspergillus sp. DHE7

Authors: Dina Helmy El-Ghonemy, Thanaa Hamed Ali

Abstract:

The aim of this study was to purify and characterize a keratinolytic enzyme produced by Aspergillus sp. DHE7 cultured in basal medium containing chicken feather as substrate. The enzyme was purified through ammonium sulfate saturation of 60%, followed by gel filtration chromatography in Sephadex G-100, with a 16.4-purification fold and recovery yield of 52.2%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the purified enzyme is a monomeric enzyme with an apparent molecular mass of 30 kDa — the purified keratinase of Aspergillus sp. DHE7 exhibited activity in a broad range of pH (7- 9) and temperature (40℃-60℃) profiles with an optimal activity at pH eight and 50℃. The keratinolytic activity was inhibited by protease inhibitors such as phenylmethylsulfonyl fluoride and ethylenediaminetetraacetate, while no reduction of activity was detected by the addition of dimethyl sulfoxide (DMSO). Bivalent cations, Ca²⁺ and Mn²⁺, were able to greatly enhance the activity of keratinase by 125.7% and 194.8%, respectively, when used at one mM final concentration. On the other hand, Cu²⁺ and Hg²⁺ inhibited the enzyme activity, which might be indicative of essential vicinal sulfhydryl groups of the enzyme for productive catalysis. Furthermore, the purified keratinase showed significant stability and compatibility against the tested commercial detergents at 37ºC. Therefore, these results suggested that the purified keratinase from Aspergillus sp. DHE7 may have potential use in the detergent industry and should be of interest in the processing of poultry feather waste.

Keywords: Aspergillus sp. DHE7, biochemical characterization, keratinase, purification, waste management

Procedia PDF Downloads 131
2697 Baseline Study for Performance Evaluation of New Generation Solar Insulation Films for Windows: A Test Bed in Singapore

Authors: Priya Pawar, Rithika Susan Thomas, Emmanuel Blonkowski

Abstract:

Due to the solar geometry of Singapore, which lay within the geographical classification of equatorial tropics, there is a great deal of thermal energy transfer to the inside of the buildings. With changing face of economic development of cities like Singapore, more and more buildings are designed to be lightweight using transparent construction materials such as glass. Increased demand for energy efficiency and reduced cooling load demands make it important for building designer and operators to adopt new and non-invasive technologies to achieve building energy efficiency targets. A real time performance evaluation study was undertaken at School of Art Design and Media (SADM), Singapore, to determine the efficiency potential of a new generation solar insulation film. The building has a window to wall ratio (WWR) of 100% and is fitted with high performance (low emissivity) double glazed units. The empirical data collected was then used to calibrate a computerized simulation model to understand the annual energy consumption based on existing conditions (baseline performance). It was found that the correlations of various parameters such as solar irradiance, solar heat flux, and outdoor air-temperatures quantification are significantly important to determine the cooling load during a particular period of testing.

Keywords: solar insulation film, building energy efficiency, tropics, cooling load

Procedia PDF Downloads 197
2696 Synthesis, Density Functional Theory (DFT) and Antibacterial Studies of Highly Functionalized Novel Spiropyrrolidine 4-Quinolone-3-Carboxylic Acids Derived from 6-Acetyl Quinolone

Authors: Thangaraj Arasakumar, Athar Ata, Palathurai Subramaniam Mohan

Abstract:

A series of novel 4-quinolone-3-carboxylic acid grafted spiropyrrolidines as new type of antibacterial agents were synthesized via multicomponent 1,3-dipolar cycloaddition reaction of an azomethine ylides with a newly prepared (E)-4-oxo-6-(3-phenyl-acryloyl)-1,4-dihydro-quinoline-3-carboxylic acids in high regioselectivity with good yields. The structure of cycloadduct characterized by FT IR, mass, 1H, 13C, 2D NMR techniques and elemental analysis. Structure and spectrometry of compound 8a has been investigated theoretically by using HF and DFT approach at B3LYP, M05-2x/6-31G* levels of theories. The optimized geometries and calculated vibrational frequencies are evaluated via comparison with experimental values. A good agreement is found between the measured and calculated values. The DFT studies support the molecular mechanism of this cycloaddition reaction and determine the molecular electrostatic potential and thermodynamic properties. Furthermore, the antibacterial activities of synthesized compounds were evaluated against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria strains (Escherichia coli, Klebsiella pneumoniae). Among 21 compounds screened, 8f and 8p were found to be more active against tested bacteria.

Keywords: antibacterial activity, azomethine ylide, DFT calculation, spirooxindole

Procedia PDF Downloads 219
2695 Temperature-Stable High-Speed Vertical-Cavity Surface-Emitting Lasers with Strong Carrier Confinement

Authors: Yun Sun, Meng Xun, Jingtao Zhou, Ming Li, Qiang Kan, Zhi Jin, Xinyu Liu, Dexin Wu

Abstract:

Higher speed short-wavelength vertical-cavity surface-emitting lasers (VCSELs) working at high temperature are required for future optical interconnects. In this work, the high-speed 850 nm VCSELs are designed, fabricated and characterized. The temperature dependent static and dynamic performance of devices are investigated by using current-power-voltage and small signal modulation measurements. Temperature-stable high-speed properties are obtained by employing highly strained multiple quantum wells and short cavity length of half wavelength. The temperature dependent photon lifetimes and carrier radiative times are determined from damping factor and resonance frequency obtained by fitting the intrinsic optical bandwidth with the two-pole transfer function. In addition, an analytical theoretical model including the strain effect is development based on model-solid theory. The calculation results indicate that the better high temperature performance of VCSELs can be attributed to the strong confinement of holes in the quantum wells leading to enhancement of the carrier transit time.

Keywords: vertical cavity surface emitting lasers, high speed modulation, optical interconnects, semiconductor lasers

Procedia PDF Downloads 129
2694 Mathematical Modeling of Eggplant Slices Drying Using Microwave-Oven

Authors: M.H. Keshek, M.N. Omar, A.H. Amer

Abstract:

Eggplant (Solanum melongena L.) is considered one of the most important crops in summer season, and it is grown in most cultivated area in Egypt. Eggplant has a very limited shelf life for freshness and physiological changes occur after harvest. Nowadays, microwave drying offers an alternative way to drying agricultural products. microwave drying is not only faster but also requiring less energy consumption than conventional drying. The main objective of this research was to evaluate using the microwave oven in Eggplant drying, to determine the optimum drying time of higher drying efficiency and lower energy consumption. The eggplants slices, having a thickness of about 5, 10, 15, and 20 mm, with diameter 50±2 mm was dried using microwave oven (KOR-9G2B) using three different levels were 450, 630, and 810 Watt (50%, 70%, and 90% of 900 Watt). The results show that, the initial moisture content of the eggplant slices was around 93 % wet basis (13.28 g water/g dry matter). The results indicated that, the moisture transfer within the sample was more rapidly during higher microwave power heating (810 watt) and lower thickness (5 mm) of the eggplant slices. In addition, the results show that, the drying efficiency increases by increasing slices thickness at power levels 450, 630 and 810 Watt. The higher drying efficiency was 83.13% occurred when drying the eggplant slices 20 mm thickness in microwave oven at power 630 Watt. the higher total energy consumption per dry kilogram was 1.275 (kWh/ dry kg) occurred at used microwave 810 Watt for drying eggplant slices 5 mm thickness, and the lower total energy consumption per dry kilogram was 0.55 (kWh/ dry kg) occurred at used microwave 810 Watt for drying eggplant slices 20 mm thickness.

Keywords: microwave drying, eggplant, drying rate, drying efficiency, energy consumption

Procedia PDF Downloads 162
2693 Tracing the Direction of Media Activism: Public Perspective

Authors: G. Arockiasamy, B. Sujeevan Kumar, Surendheran

Abstract:

Human progress and development are highly influenced by the power of information access and technology. A global and multi-national transformation all over the word is possible due to digitalization. In the process of exchanging information, experience, and resources, there is a radical shift in who controls them. Mass media has turned the world into a global village by strengthening communication network. As a result, a new digital culture has emerged as a social network commonly known as new media. Today the advancement of technology is at the doorstep of everyone linking to anywhere. The traditional social restrictions are broken down by the new type of virtual communication modality that transcends people beyond boundaries At the same time media empire has invaded every nook and corner of the world through great expansion. Media activism is growing stronger and stronger but the truth and true meaning lost in the process. This paper explores the peoples’ attitude to media activism and tracing its direction. The methodology employed is random sampling survey and content analysis method. Both qualitatively and quantitatively measured. The findings tend to show 60 percent indicate media activism as positive and others indicate as negative. As a conclusion, media activism has danger within but depends on nature of the development of human orientation.

Keywords: media activism, media industry, program, truth information, orientation and nature

Procedia PDF Downloads 212