Search results for: Amro Issam Hamed Attia Ramadan
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 328

Search results for: Amro Issam Hamed Attia Ramadan

88 The Impact of Macroeconomic Factors on Tehran Stock Exchange Index during Economic and Oil Sanctions between January 2006 and December 2012

Authors: Hamed Movahedizadeh, Annuar Md Nassir, Mehdi Karimimalayer, Navid Samimi Sedeh, Ehsan Bagherpour

Abstract:

The aim of this paper is to evaluate Tehran’s Stock Exchange (TSE) performance regarding with impact of four macroeconomic factors including world crude Oil Price (OP), World Gold Price (GP), Consumer Price Index (CPI) and total Supplied Oil by Iran (SO) from January 2006 to December 2012 that Iran faced with economic and oil sanctions. Iran's exports of crude oil and lease condensate reduced to roughly 1.5 million barrels per day (bbl/d) in 2012, compared to 2.5 million bbl/d in 2011 due to hard sanctions. Monthly data are collected and subjected to a battery of tests through ordinary least square by EViews7. This study found that gold price and oil price are positively correlated with stock returns while total oil supplied and consumer price index have negative relationship with stock index, however, consumer price index tends to become insignificant in stock index. While gold price and consumer price index have short run relationship with TSE index at 10% of significance level this amount for oil price is significant at 5% and there is no significant short run relationship between supplied oil and Tehran stock returns. Moreover, this study found that all macroeconomic factors have long-run relationship with Tehran Stock Exchange Index.

Keywords: consumer price index, gold price, macroeconomic, oil price, sanction, stock market, supplied oil

Procedia PDF Downloads 490
87 Theoretical Model of a Flat Plate Solar Collector Integrated with Phase Change Material

Authors: Mouna Hamed, Ammar B. Brahim

Abstract:

The objective of this work was to develop a theoretical model to study the dynamic thermal behavior of a flat plate solar collector integrated with a phase change material (PCM). The PCM acted as a heat source for the solar system during low intensity solar radiation and night. The energy balance equations for the various components of the collector as well as for the PCM were formulated and numerically solved using MATLAB computational program. The effect of natural convection on heat during the melting process was taken into account by using an effective thermal conductivity. The model was used to investigate the effect of inlet water temperature, water mass flow rate, and PCM thickness on the outlet water temperature and the melt fraction during charging and discharging modes. A comparison with a collector without PCM was made. Results showed that charging and discharging processes of PCM have six stages. The adding of PCM caused a decrease in temperature during charge and an increase during discharge. The rise was most enhanced for higher inlet water temperature, PCM thickness and for lower mass flow rate. Analysis indicated that the complete melting time was shorter than the solidification time due to the high heat transfer coefficient during melting. The increases in PCM height and mass flow rate were not linear with the melting and solidification times.

Keywords: thermal energy storage, phase change material, melting, solidification

Procedia PDF Downloads 347
86 Using Building Information Modeling in Green Building Design and Performance Optimization

Authors: Moataz M. Hamed, Khalid S. M. Al Hagla, Zeyad El Sayad

Abstract:

Thinking in design energy-efficiency and high-performance green buildings require a different design mechanism and design approach than conventional buildings to achieve more sustainable result. By reasoning about specific issues at the correct time in the design process, the design team can minimize negative impacts, maximize building performance and keep both first and operation costs low. This paper attempts to investigate and exploit the sustainable dimension of building information modeling (BIM) in designing high-performance green buildings that require less energy for operation, emit less carbon dioxide and provide a conducive indoor environment for occupants through early phases of the design process. This objective was attained by a critical and extensive literature review that covers the following issues: the value of considering green strategies in the early design stage, green design workflow, and BIM-based performance analysis. Then the research proceeds with a case study that provides an in-depth comparative analysis of building performance evaluation between an office building in Alexandria, Egypt that was designed by the conventional design process with the same building if taking into account sustainability consideration and BIM-based sustainable analysis integration early through the design process. Results prove that using sustainable capabilities of building information modeling (BIM) in early stages of the design process side by side with green design workflow promote buildings performance and sustainability outcome.

Keywords: BIM, building performance analysis, BIM-based sustainable analysis, green building design

Procedia PDF Downloads 343
85 Pricing, Production and Inventory Policies Manufacturing under Stochastic Demand and Continuous Prices

Authors: Masoud Rabbani, Majede Smizadeh, Hamed Farrokhi-Asl

Abstract:

We study jointly determining prices and production in a multiple period horizon under a general non-stationary stochastic demand with continuous prices. In some periods we need to increase capacity of production to satisfy demand. This paper presents a model to aid multi-period production capacity planning by quantifying the trade-off between product quality and production cost. The product quality is estimated as the statistical variation from the target performances obtained from the output tolerances of the production machines that manufacture the components. We consider different tolerance for different machines that use to increase capacity. The production cost is estimated as the total cost of owning and operating a production facility during the planning horizon.so capacity planning has cost that impact on price. Pricing products often turns out to be difficult to measure them because customers have a reservation price to pay that impact on price and demand. We decide to determine prices and production for periods after enhance capacity and consider reservation price to determine price. First we use an algorithm base on fuzzy set of the optimal objective function values to determine capacity planning by determine maximize interval from upper bound in minimum objectives and define weight for objectives. Then we try to determine inventory and pricing policies. We can use a lemma to solve a problem in MATLAB and find exact answer.

Keywords: price policy, inventory policy, capacity planning, product quality, epsilon -constraint

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84 The Effect of Naringenin on the Apoptosis in T47D Cell Line of Breast Cancer

Authors: AliAkbar Hafezi, Jahanbakhsh Asadi, Majid Shahbazi, Alijan Tabarraei, Nader Mansour Samaei, Hamed Sheibak, Roghaye Gharaei

Abstract:

Background: Breast cancer is the most common cancer in women. In most cancer cells, apoptosis is blocked. As for the importance of apoptosis in cancer cell death and the role of different genes in its induction or inhibition, the search for compounds that can begin the process of apoptosis in tumor cells is discussed as a new strategy in anticancer drug discovery. The aim of this study was to investigate the effect of Naringenin (NGEN) on the apoptosis in the T47D cell line of breast cancer. Materials and Methods: In this experimental study in vitro, the T47D cell line of breast cancer was selected as a sample. The cells at 24, 48, and 72 hours were treated with doses of 20, 200, and 1000 µm of Naringenin. Then, the transcription levels of the genes involved in apoptosis, including Bcl-2, Bax, Caspase 3, Caspase 8, Caspase 9, P53, PARP-1, and FAS, were assessed using Real Time-PCR. The collected data were analyzed using IBM SPSS Statistics 24.0. Results: The results showed that Naringenin at doses of 20, 200, and 1000 µm in all three times of 24, 48, and 72 hours increased the expression of Caspase 3, P53, PARP-1 and FAS and reduced the expression of Bcl-2 and increased the Bax/Bcl-2 ratio, nevertheless in none of the studied doses and times, had not a significant effect on the expression of Bax, Caspase 8 and Caspase 9. Conclusion: This study indicates that Naringenin can reduce the growth of some cancer cells and cause their deaths through increased apoptosis and decreased anti-apoptotic Bcl-2 gene expression and, resulting in the induction of apoptosis via both internal and external pathways.

Keywords: apoptosis, breast cancer, naringenin, T47D cell line

Procedia PDF Downloads 53
83 Numerical Investigation of the Effect of Geometrical Shape of Plate Heat Exchangers on Heat Transfer Efficiency

Authors: Hamed Sanei, Mohammad Bagher Ayani

Abstract:

Optimizations of Plate Heat Exchangers (PHS) have received great attention in the past decade. In this study, heat transfer and pressure drop coefficients are compared for rectangular and circular PHS employing numerical simulations. Plates are designed to have equivalent areas. Simulations were implemented to investigate the efficiency of PHSs considering heat transfer, friction factor and pressure drop. Amount of heat transfer and pressure drop was obtained for different range of Reynolds numbers. These two parameters were compared with aim of F "weighting factor correlation". In this comparison, the minimum amount of F indicates higher efficiency. Results reveal that the F value for rectangular shape is less than circular plate, and hence using rectangular shape of PHS is more efficient than circular one. It was observed that, the amount of friction factor is correlated to the Reynolds numbers, such that friction factor decreased in both rectangular and circular plates with an increase in Reynolds number. Furthermore, such simulations revealed that the amount of heat transfer in rectangular plate is more than circular plate for different range of Reynolds numbers. The difference is more distinct for higher Reynolds number. However, amount of pressure drop in circular plate is less than rectangular plate for the same range of Reynolds numbers which is considered as a negative point for rectangular plate efficiency. It can be concluded that, while rectangular PHSs occupy more space than circular plate, the efficiency of rectangular plate is higher.

Keywords: Chevron corrugated plate heat exchanger, heat transfer, friction factor, Reynolds numbers

Procedia PDF Downloads 304
82 Chronic Pesticides Exposure and Certain Endocrine Functions Among Farmers in East Almnaif District, Ismailia, Egypt

Authors: Amani Waheed, Mostafa Kofi, Shaymaa Attia, Soha Younis, Basma Abdel Hadi

Abstract:

Background: Exposure to pesticides is one of the most important occupational risks among farmers in developing countries. Along with the wide use of pesticides in the world, the concerns over their health impacts are rapidly growing. Objective: To investigate thyroid and reproductive hormones and fasting blood glucose levels among farmers chronically exposed to pesticide from East Almnaif district, Ismailia governorate. Methods: An analytical cross-sectional study was conducted on 43 farmers with active involvement pesticides handling and 43 participants not occupationally exposed to pesticides as the control group. A structured interview questionnaire measuring the sociodemographic characteristics, pesticides exposure characteristics, and safety measures was used. General examination including measurements of height, weight, and blood pressure was done. Moreover, levels of plasma cholinesterase enzyme (PChE), glucose, as well as reproductive and thyroid hormones (TSH, T4, and testosterone) were determined. Results: There were no statistically significant differences between both groups regarding their age, educational level, smoking status, and body mass index. The mean duration of exposure was 20.60 11.06 years. Majority of farmers (76.7%) did not use any personal protective equipment (PPE) during pesticides handling. The mean systolic blood pressure among exposed farmers was greater (134.88 17.18 mm Hg) compared to control group (125 14.69 mm Hg) with statistically significant difference (p = 0.003). The mean diastolic blood pressure was higher (84.02 8.69 mm Hg) compared to control group (78.79 8.98 mm Hg) with statistically significant difference (p = 0.006). The pesticide exposed farmers had statistically significant lower level of PChE (3969.93 1841U/L) than control group (4879.29 1950.08 U/L). Additionally, TSH level was significantly higher in exposed farmers (median =1.39µIU/ml) compared to controls (median = 0.91 µIU/ml) (p=0.032). While, the exposed group had a lower T4 level (6.91 1.91 µg/dl) compared to the control group (7.79 2.10µg/dl), with the statistically significant difference between the two groups (p = 0.045). The exposed group had significantly lower level of testosterone hormone (median=3.37 ng/ml) compared to the control group (median= 6.22 ng/ml) (p=0.003). While, the exposed farmers had statistically insignificant higher level of fasting blood glucose (median =89 mg/dl) than the controls (median=88 mg/dl). Furthermore, farmers who did not use PPE had statistically significant lower level of T4 (6.57 1.81µg/dl) than farmers who used PPE during handling of pesticides (8.01 1.89 µg/dl). Conclusion: Chronic exposure to pesticides exerts disturbing action on reproductive function and thyroid function of the male farmers.

Keywords: chronic occupational pesticide exposure, Diabetes mellitus, male reproductive hormones, thyroid function

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81 An Integrated Framework for Seismic Risk Mitigation Decision Making

Authors: Mojtaba Sadeghi, Farshid Baniassadi, Hamed Kashani

Abstract:

One of the challenging issues faced by seismic retrofitting consultants and employers is quick decision-making on the demolition or retrofitting of a structure at the current time or in the future. For this reason, the existing models proposed by researchers have only covered one of the aspects of cost, execution method, and structural vulnerability. Given the effect of each factor on the final decision, it is crucial to devise a new comprehensive model capable of simultaneously covering all the factors. This study attempted to provide an integrated framework that can be utilized to select the most appropriate earthquake risk mitigation solution for buildings. This framework can overcome the limitations of current models by taking into account several factors such as cost, execution method, risk-taking and structural failure. In the newly proposed model, the database and essential information about retrofitting projects are developed based on the historical data on a retrofit project. In the next phase, an analysis is conducted in order to assess the vulnerability of the building under study. Then, artificial neural networks technique is employed to calculate the cost of retrofitting. While calculating the current price of the structure, an economic analysis is conducted to compare demolition versus retrofitting costs. At the next stage, the optimal method is identified. Finally, the implementation of the framework was demonstrated by collecting data concerning 155 previous projects.

Keywords: decision making, demolition, construction management, seismic retrofit

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80 Utilizing Artificial Intelligence to Predict Post Operative Atrial Fibrillation in Non-Cardiac Transplant

Authors: Alexander Heckman, Rohan Goswami, Zachi Attia, Paul Friedman, Peter Noseworthy, Demilade Adedinsewo, Pablo Moreno-Franco, Rickey Carter, Tathagat Narula

Abstract:

Background: Postoperative atrial fibrillation (POAF) is associated with adverse health consequences, higher costs, and longer hospital stays. Utilizing existing predictive models that rely on clinical variables and circulating biomarkers, multiple societies have published recommendations on the treatment and prevention of POAF. Although reasonably practical, there is room for improvement and automation to help individualize treatment strategies and reduce associated complications. Methods and Results: In this retrospective cohort study of solid organ transplant recipients, we evaluated the diagnostic utility of a previously developed AI-based ECG prediction for silent AF on the development of POAF within 30 days of transplant. A total of 2261 non-cardiac transplant patients without a preexisting diagnosis of AF were found to have a 5.8% (133/2261) incidence of POAF. While there were no apparent sex differences in POAF incidence (5.8% males vs. 6.0% females, p=.80), there were differences by race and ethnicity (p<0.001 and 0.035, respectively). The incidence in white transplanted patients was 7.2% (117/1628), whereas the incidence in black patients was 1.4% (6/430). Lung transplant recipients had the highest incidence of postoperative AF (17.4%, 37/213), followed by liver (5.6%, 56/1002) and kidney (3.6%, 32/895) recipients. The AUROC in the sample was 0.62 (95% CI: 0.58-0.67). The relatively low discrimination may result from undiagnosed AF in the sample. In particular, 1,177 patients had at least 1 AI-ECG screen for AF pre-transplant above .10, a value slightly higher than the published threshold of 0.08. The incidence of POAF in the 1104 patients without an elevated prediction pre-transplant was lower (3.7% vs. 8.0%; p<0.001). While this supported the hypothesis that potentially undiagnosed AF may have contributed to the diagnosis of POAF, the utility of the existing AI-ECG screening algorithm remained modest. When the prediction for POAF was made using the first postoperative ECG in the sample without an elevated screen pre-transplant (n=1084 on account of n=20 missing postoperative ECG), the AUROC was 0.66 (95% CI: 0.57-0.75). While this discrimination is relatively low, at a threshold of 0.08, the AI-ECG algorithm had a 98% (95% CI: 97 – 99%) negative predictive value at a sensitivity of 66% (95% CI: 49-80%). Conclusions: This study's principal finding is that the incidence of POAF is rare, and a considerable fraction of the POAF cases may be latent and undiagnosed. The high negative predictive value of AI-ECG screening suggests utility for prioritizing monitoring and evaluation on transplant patients with a positive AI-ECG screening. Further development and refinement of a post-transplant-specific algorithm may be warranted further to enhance the diagnostic yield of the ECG-based screening.

Keywords: artificial intelligence, atrial fibrillation, cardiology, transplant, medicine, ECG, machine learning

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79 Anterior Segment Optical Coherence Tomography Study of Cornea and Tear Film Parameters in Juvenile Systemic Lupus Erythematous Patients

Authors: Mohamed Salah El-Din Mahmoud, Ahmed Hamed, Asmaa Anwar Mohamed

Abstract:

Purpose: To study the tear film parameters, total corneal thickness (CT), corneal epithelial thickness and, corneal power in Juvenile systemic lupus erythematosus (JSLE) patients compared to age-matched controls using anterior segment optical coherence tomography (AS-OCT). Methods: This was a cross-sectional study. Study participants were divided into 2 groups: Group A: 75 eyes of JSLE patients, Group B: 75 eyes of healthy controls. Tear meniscus height (TMH), tear meniscus depth (TMD), and tear meniscus area (TMA) were the lower tear meniscus parameters that were measured. The corneal power, CT, and epithelial thickness were all determined automatically. Results: In the JSLE group, the range of age was 10 to 15 years while the control group was 11 to 16 years. TMH, TMA, and TMD were 527.7±46.8, 0.059±0.015 and 343.3±59.9 respectively in JSLE group while 525.4±44.6, 0.058±0.011 and 340.6±58.0 respectively in control group without significant difference (p-value<0.001). The corneal power was 43.3±0.55 in the JSLE while 43.2±0.54 in the control group without significant difference (p-value= 0.407). CT was 551.1±13.5 in JSLE group while 551.2±15.3 in control group without significant difference (p-value= 0.982). Epithelial thickness was 52.66±1.35 in the JSLE group while 52.60±1.36 in the control group without significant difference (p-value= 0.765). Conclusion: We demonstrated no significant difference in tear meniscus dimensions, CT, epithelial thickness, and corneal power in the JSLE patients compared to age-matched controls using AS-OCT.

Keywords: tear film, ASOCT, JSLE, pachymetry, corneal thickness

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78 Scientific and Technical Basis for the Application of Textile Structures in Glass Using Pate De Verre Technique

Authors: Walaa Hamed Mohamed Hamza

Abstract:

Textile structures are the way in which the threading process of both thread and loom is done together to form the woven. Different methods of attaching the clothing and the flesh produce different textile structures, which differ in their surface appearance from each other, including so-called simple textile structures. Textile compositions are the basis of woven fabric, through which aesthetic values can be achieved in the textile industry by weaving threads of yarn with the weft at varying degrees that may reach the total control of one of the two groups on the other. Hence the idea of how art and design can be used using different textile structures under the modern techniques of pate de verre. In the creation of designs suitable for glass products employed in the interior architecture. The problem of research: The textile structures, in general, have a significant impact on the appearance of the fabrics in terms of form and aesthetic. How can we benefit from the characteristics of different textile compositions in different glass designs with different artistic values. The research achieves its goal by the investment of simple textile structures in innovative artistic designs using the pate de verre technique, as well as the use of designs resulting from the textile structures in the external architecture to add various aesthetic values. The importance of research in the revival of heritage using ancient techniques, as well as synergy between different fields of applied arts such as glass and textile, and also study the different and diverse effects resulting from each fabric composition and the possibility of use in various designs in the interior architecture. The research will be achieved that by investing in simple textile compositions, innovative artistic designs produced using pate de verre technology can be used in interior architecture.

Keywords: glass, interior architecture, pate de verre, textile structures

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77 Computational Pipeline for Lynch Syndrome Detection: Integrating Alignment, Variant Calling, and Annotations

Authors: Rofida Gamal, Mostafa Mohammed, Mariam Adel, Marwa Gamal, Marwa kamal, Ayat Saber, Maha Mamdouh, Amira Emad, Mai Ramadan

Abstract:

Lynch Syndrome is an inherited genetic condition associated with an increased risk of colorectal and other cancers. Detecting Lynch Syndrome in individuals is crucial for early intervention and preventive measures. This study proposes a computational pipeline for Lynch Syndrome detection by integrating alignment, variant calling, and annotation. The pipeline leverages popular tools such as FastQC, Trimmomatic, BWA, bcftools, and ANNOVAR to process the input FASTQ file, perform quality trimming, align reads to the reference genome, call variants, and annotate them. It is believed that the computational pipeline was applied to a dataset of Lynch Syndrome cases, and its performance was evaluated. It is believed that the quality check step ensured the integrity of the sequencing data, while the trimming process is thought to have removed low-quality bases and adaptors. In the alignment step, it is believed that the reads were accurately mapped to the reference genome, and the subsequent variant calling step is believed to have identified potential genetic variants. The annotation step is believed to have provided functional insights into the detected variants, including their effects on known Lynch Syndrome-associated genes. The results obtained from the pipeline revealed Lynch Syndrome-related positions in the genome, providing valuable information for further investigation and clinical decision-making. The pipeline's effectiveness was demonstrated through its ability to streamline the analysis workflow and identify potential genetic markers associated with Lynch Syndrome. It is believed that the computational pipeline presents a comprehensive and efficient approach to Lynch Syndrome detection, contributing to early diagnosis and intervention. The modularity and flexibility of the pipeline are believed to enable customization and adaptation to various datasets and research settings. Further optimization and validation are believed to be necessary to enhance performance and applicability across diverse populations.

Keywords: Lynch Syndrome, computational pipeline, alignment, variant calling, annotation, genetic markers

Procedia PDF Downloads 80
76 Effects of Clozapine and Risperidone Antipsychotic Drugs on the Expression of CACNA1C and Behavioral Changes in Rat ‘Ketamine Model of Schizophrenia

Authors: Mehrnoosh Azimi Sanavi, Hamed Ghazvini, Mehryar Zargari, Hossein Ghalehnoei, Zahra Hosseini-khah

Abstract:

Objectives: Calcium Voltage-Gated Channel Subunit Alpha1 C (CACNA1C) is one of the most important genes associated with schizophrenia. Methods: 45 male Wistar rats were divided into 5 groups: saline, control, ketamine, clozapine, and risperidone. Animals in ketamine, risperidone, and clozapine groups received ketamine (30 mg/ kg-i.p.) for 10 days. After the last injection of ketamine, we started injecting clozapine (7.5 mg/kg-i.p.) risperidone (1 mg/kg-i.p.) for up to 28 days. Twenty-four hours after the last injection, open field, social interaction, and elevated plus-maze tests, and gene expression in the hippocampus were performed. Results: The results of the social interaction test revealed a significant decrease in cumulative time with ketamine compared with the saline group and an increase with clozapine and risperidone compared with the ketamine group. Moreover, results from the elevated plus-maze test demonstrated a critical decrease in open-arm time and an increase in close-arm time with ketamine compared with saline, as well as an increase in open-arm time with risperidone compared with ketamine. Further results revealed a significant increase in rearing and grooming with ketamine compared to saline, as well as a decrease with risperidone and clozapine compared to ketamine. There were no significant differences in CACNA1C gene expression between groups in the rat hippocampus. In brief, the results of this study indicated that clozapine and risperidone could partially improve cognitive impairments in the rat. However, our findings demonstrated that this treatment is not related to CACNA1C gene expression.

Keywords: schizophrenia, ketamine, clozapine, risperidone

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75 Corneal Confocal Microscopy As a Surrogate Marker of Neuronal Pathology In Schizophrenia

Authors: Peter W. Woodruff, Georgios Ponirakis, Reem Ibrahim, Amani Ahmed, Hoda Gad, Ioannis N. Petropoulos, Adnan Khan, Ahmed Elsotouhy, Surjith Vattoth, Mahmoud K. M. Alshawwaf, Mohamed Adil Shah Khoodoruth, Marwan Ramadan, Anjushri Bhagat, James Currie, Ziyad Mahfoud, Hanadi Al Hamad, Ahmed Own, Peter Haddad, Majid Alabdulla, Rayaz A. Malik

Abstract:

Introduction:- We aimed to test the hypothesis that, using corneal confocal microscopy (a non-invasive method for assessing corneal nerve fibre integrity), patients with schizophrenia would show neuronal abnormalities compared with healthy participants. Schizophrenia is a neurodevelopmental and progressive neurodegenerative disease, for which there are no validated biomarkers. Corneal confocal microscopy (CCM) is a non-invasive ophthalmic imaging biomarker that can be used to detect neuronal abnormalities in neuropsychiatric syndromes. Methods:- Patients with schizophrenia (DSM-V criteria) without other causes of peripheral neuropathy and healthy controls underwent CCM, vibration perception threshold (VPT) and sudomotor function testing. The diagnostic accuracy of CCM in distinguishing patients from controls was assessed using the area under the curve (AUC) of the Receiver Operating Characterstics (ROC) curve. Findings:- Participants with schizophrenia (n=17) and controls (n=38) with comparable age (35.7±8.5 vs 35.6±12.2, P=0.96) were recruited. Patients with schizophrenia had significantly higher body weight (93.9±25.5 vs 77.1±10.1, P=0.02), lower Low Density Lipoproteins (2.6±1.0 vs 3.4±0.7, P=0.02), but comparable systolic and diastolic blood pressure, HbA1c, total cholesterol, triglycerides and High Density Lipoproteins were comparable with control participants. Patients with schizophrenia had significantly lower corneal nerve fiber density (CNFD, fibers/mm2) (23.5±7.8 vs 35.6±6.5, p<0.0001), branch density (CNBD, branches/mm2) (34.4±26.9 vs 98.1±30.6, p<0.0001), and fiber length (CNFL, mm/mm2) (14.3±4.7 vs 24.2±3.9, p<0.0001) but no difference in VPT (6.1±3.1 vs 4.5±2.8, p=0.12) and electrochemical skin conductance (61.0±24.0 vs 68.9±12.3, p=0.23) compared with controls. The diagnostic accuracy of CNFD, CNBD and CNFL to distinguish patients with schizophrenia from healthy controls were, according to the AUC, (95% CI): 87.0% (76.8-98.2), 93.2% (84.2-102.3), 93.2% (84.4-102.1), respectively. Conclusion:- In conclusion, CCM can be used to help identify neuronal changes and has a high diagnostic accuracy to distinguish subjects with schizophrenia from healthy controls.

Keywords:

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74 A Neurofeedback Learning Model Using Time-Frequency Analysis for Volleyball Performance Enhancement

Authors: Hamed Yousefi, Farnaz Mohammadi, Niloufar Mirian, Navid Amini

Abstract:

Investigating possible capacities of visual functions where adapted mechanisms can enhance the capability of sports trainees is a promising area of research, not only from the cognitive viewpoint but also in terms of unlimited applications in sports training. In this paper, the visual evoked potential (VEP) and event-related potential (ERP) signals of amateur and trained volleyball players in a pilot study were processed. Two groups of amateur and trained subjects are asked to imagine themselves in the state of receiving a ball while they are shown a simulated volleyball field. The proposed method is based on a set of time-frequency features using algorithms such as Gabor filter, continuous wavelet transform, and a multi-stage wavelet decomposition that are extracted from VEP signals that can be indicative of being amateur or trained. The linear discriminant classifier achieves the accuracy, sensitivity, and specificity of 100% when the average of the repetitions of the signal corresponding to the task is used. The main purpose of this study is to investigate the feasibility of a fast, robust, and reliable feature/model determination as a neurofeedback parameter to be utilized for improving the volleyball players’ performance. The proposed measure has potential applications in brain-computer interface technology where a real-time biomarker is needed.

Keywords: visual evoked potential, time-frequency feature extraction, short-time Fourier transform, event-related spectrum potential classification, linear discriminant analysis

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73 Chemical Analysis, Antioxidant Activity and Antimicrobial Activity of Isolated Compounds and Essential Oil from Callistemon citrinus Leaf

Authors: Manal M. Hamed, Mosad A. Ghareeb, Abdel-Aleem H. Abdel-Aleem, Amal M. Saad, Mohamed S. Abdel-Aziz, Asmaa H. Hadad

Abstract:

Natural products derived from medicinal plants provide unlimited opportunities for a new medication leads because of the unmatched accessibility of chemical variation. Six compounds were isolated from the n-butanol extract of Callistemon citrinus (Family Myrtaceae), they were identified as; nepetolide (1), callislignan A (2), 6,8-dimethoxy-4,5-dimethyl-3-methyleneisochroman-1-one (3), 3-methyl-7-O-benzoyl-β-D-glucopyranoside (4), 5, 7, 3', 5'-tetrahydroxy-6, 8-di-C-methyl flavanone (5), and (2R,3R,4S,5S)-2,4-bis(4-hydroxyphenyl)-3,5-dihydroxy-tetrahydropyran (6). The isolated compounds were evaluated as antioxidant and antimicrobial agents. The antioxidant activities of the compounds were determined using DPPH-radical scavenging and total antioxidant capacity (TAC) assays. The results indicated that compound (5) was most active in its capacity to scavenge free radicals in the DPPH assay [SC50 value, 4.65 ± 0.74μg/mL] compared to the standard ascorbic acid and exhibited the highest activity in the TAC assay (610.45 ± 1.67mg AAE/g compound). The pure isolates were tested for their antimicrobial activity against four pathogenic microbial strains including Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Candida albicans. Also, the GC/MS analysis of its leaves essential oil presented nine identified compounds representing 91% of the total oil constituents. The outcomes got from this study give a reasonable justification for the medicinal uses of Callistemon citrinus plant.

Keywords: Callistemon citrinus, flavanone, antioxidant activity, antimicrobial activity, essential oil, Myrtaceae

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72 Investigating the Minimum RVE Size to Simulate Poly (Propylene carbonate) Composites Reinforced with Cellulose Nanocrystals as a Bio-Nanocomposite

Authors: Hamed Nazeri, Pierre Mertiny, Yongsheng Ma, Kajsa Duke

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The background of the present study is the use of environment-friendly biopolymer and biocomposite materials. Among the recently introduced biopolymers, poly (propylene carbonate) (PPC) has been gaining attention. This study focuses on the size of representative volume elements (RVE) in order to simulate PPC composites reinforced by cellulose nanocrystals (CNCs) as a bio-nanocomposite. Before manufacturing nanocomposites, numerical modeling should be implemented to explore and predict mechanical properties, which may be accomplished by creating and studying a suitable RVE. In other studies, modeling of composites with rod shaped fillers has been reported assuming that fillers are unidirectionally aligned. But, modeling of non-aligned filler dispersions is considerably more difficult. This study investigates the minimum RVE size to enable subsequent FEA modeling. The matrix and nano-fillers were modeled using the finite element software ABAQUS, assuming randomly dispersed fillers with a filler mass fraction of 1.5%. To simulate filler dispersion, a Monte Carlo technique was employed. The numerical simulation was implemented to find composite elastic moduli. After commencing the simulation with a single filler particle, the number of particles was increased to assess the minimum number of filler particles that satisfies the requirements for an RVE, providing the composite elastic modulus in a reliable fashion.

Keywords: biocomposite, Monte Carlo method, nanocomposite, representative volume element

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71 Applying (1, T) Ordering Policy in a Multi-Vendor-Single-Buyer Inventory System with Lost Sales and Poisson Demand

Authors: Adel Nikfarjam, Hamed Tayebi, Sadoullah Ebrahimnejad

Abstract:

This paper considers a two-echelon inventory system with a number of warehouses and a single retailer. The retailer replenishes its required items from warehouses, and assembles them into a single final product. We assume that each warehouse supplies only one kind of the raw material for the retailer. The demand process of the final product is assumed to be Poissson, and unsatisfied demand of the final product will be lost. The retailer applies one-for-one-period ordering policy which is also known as (1, T) ordering policy. In this policy the retailer orders to each warehouse a fixed quantity of each item at fixed time intervals, which the fixed quantity is equal to the utilization of the item in the final product. Since, this policy eliminates all demand uncertainties at the upstream echelon, the standard lot sizing model can be applied at all warehouses. In this paper, we calculate the total cost function of the inventory system. Then, based on this function, we present a procedure to obtain the optimal time interval between two consecutive order placements from retailer to the warehouses, and the optimal order quantities of warehouses (assuming that there are positive ordering costs at warehouses). Finally, we present some numerical examples, and conduct numerical sensitivity analysis for cost parameters.

Keywords: two-echelon supply chain, multi-vendor-single-buyer inventory system, lost sales, Poisson demand, one-for-one-period policy, lot sizing model

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70 Fatty Acids and Inflammatory Protein Biomarkers in Freshly Frozen Plasma Samples from Patients with and without COVID-19

Authors: Alaa Hamed Habib

Abstract:

The Coronavirus disease 2019 (COVID-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and associated with systemic inflammation. Inflammation is an important process that follows infection and facilitates the repair of damaged tissue. Polyunsaturated fatty acids play an important role in the inflammatory process. These lipids can target transcription factors to modulate gene expression and protein function. Here, we evaluated whether differences in basal levels of different types of biomarkers can be detected in freshly frozen plasma samples from patients with and without COVID19. Fatty acid methyl ester (FAME) analysis showed a decrease in arachidic acid and myristic acid, but an increase in caprylic acid, palmitic acid, and eicosenoic acid in the plasma of COVID-19 patients compared to non-COVID19 patients. Multiple chemokines, including IP-10, MCP-1, and MIP-1 beta, were increased in the COVID-19 group compared to the non-COVID-19 group. Similarly, cytokines including IL-1 alpha and IL-8, and cell adhesion and inflammatory response markers including ICAM-1 and E-selectin were greater in the plasma of COVID-19 patients compared to non-COVID-19 patients. A baseline signature of specific polyunsaturated fatty acids, cytokines, and chemokines present in the plasma after COVID-19 viral infection may serve as biomarkers that can be useful in various applications, including determination of the severity of infection, an indication of disease prognosis and consideration for therapeutic options.

Keywords: MARKS, COVID 19, UEVS NON COVIDS, kidneys, nanoparticles

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69 Vibration Analysis of Magnetostrictive Nano-Plate by Using Modified Couple Stress and Nonlocal Elasticity Theories

Authors: Hamed Khani Arani, Mohammad Shariyat, Armaghan Mohammadian

Abstract:

In the present study, the free vibration of magnetostrictive nano-plate (MsNP) resting on the Pasternak foundation is investigated. Firstly, the modified couple stress (MCS) and nonlocal elasticity theories are compared together and taken into account to consider the small scale effects; in this paper not only two theories are analyzed but also it improves the MCS theory is more accurate than nonlocal elasticity theory in such problems. A feedback control system is utilized to investigate the effects of a magnetic field. First-order shear deformation theory (FSDT), Hamilton’s principle and energy method are utilized in order to drive the equations of motion and these equations are solved by differential quadrature method (DQM) for simply supported boundary conditions. The MsNP undergoes in-plane forces in x and y directions. In this regard, the dimensionless frequency is plotted to study the effects of small scale parameter, magnetic field, aspect ratio, thickness ratio and compression and tension loads. Results indicate that these parameters play a key role on the natural frequency. According to the above results, MsNP can be used in the communications equipment, smart control vibration of nanostructure especially in sensor and actuators such as wireless linear micro motor and smart nano valves in injectors.

Keywords: feedback control system, magnetostrictive nano-plate, modified couple stress theory, nonlocal elasticity theory, vibration analysis

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68 Induction of Cytotoxicity and Apoptosis in Ovarian Cancer Cell Line (CAOV-3) by an Isoquinoline Alkaloid Isolated from Enicosanthellum pulchrum (King) Heusden

Authors: Noraziah Nordin, Najihah Mohd Hashim, Nazia Abdul Majid, Mashitoh Abdul Rahman, Hamed Karimian, Hapipah Mohd Ali

Abstract:

Enicosanthellum pulchrum belongs to family Annonaceae is also known as family of 'mempisang' in Malaysia. Liriodenine was isolated by prep-HPLC method. This method was first technique used for the isolation of this compound. The structure of the liriodenine was elucidated by 1D and 2D spectroscopy techniques. Liriodenine was tested on ovarian cancer cells line (CAOV-3) for MTT, AO/PI and cytotoxicity 3 assays. The MTT assay was performed to determine the cytotoxicity effect of lirodenine on CAOV-3 cells. The morphological changes on CAOV-3 cells were observed by AO/PI assay for the early and late stage of apoptosis, as well as necrosis. Meanwhile, the measurement of cell loss, nuclear morphology, DNA content, cell membrane permeability, mitochondrial membrane potential changes and cytochrome c release from mitochondria were detected through cytotoxicity 3 assay. The IC50 results showed liriodenine inhibits the growth of CAOV-3 cells after 24 h of treatment at 10.25 ± 1.06 µg/mL. After 48 and 72 h of treatments, the IC50 values were decreased to 7.65 ± 0:07 and 6.35 ± 1.62 µg/mL, respectively. The morphology changes can be seen on CAOV-3 with a production of cell membrane blebbing, cromatin condensation and apoptotic bodies with increasing time of treatment from 24 to 72 h. Evaluation of cytotoxicity 3 on CAOV-3 cells after treated with liriodenine, resulting loss of mitochondrial membrane potential and release of cytochrome c from mitochondria. The results demonstrated the capability of liriodenine as a promising anticancer agent, particularly on human ovarian cancer.

Keywords: Enicosanthellum pulchrum, ovarian cancer, apoptosis, cytotoxicity

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67 Contemporary World Values: The Effects of Quality of Brand-Generated Visual Contents on Customer Engagement Behaviours in Social Commerce

Authors: Hamed Azad, Azadeh M. Ardakani

Abstract:

Visual content, as an integral part of social media marketing, is growing dramatically. They are, in different technological usage categories (i.e., photos, graphics, animation IGTV, Stories, Livestreams, and Reels), associated with improving customer engagement behaviours (CEBs) in social commerce (SC). However, few researchers have explored the impact of specific and occasional contents that respect green products, gender equality, religious freedom, and LGBTs' rights. This study aims to compare and analyse how the ten best global brands (Interbrand's) in different categories communicate with customers on Instagram. Netnography approach and method used to conduct the data collection and data analysis of 1072 Instagram posts and 10494 comments. The results show that brands in fashion, sport, and homeware categories (H&M, Nike, and Ikea) emerge to use more effective content with the above global values elements than other brand categories. Findings also indicate that some different themes such as celebrities, models, pets, kids, aged and disabled people are part of visual management strategies on Instagram brands' pages. This research aims to inform researchers to consider all aspects of visual elements in content quality and marketing managers to increase brand optimisation, awareness, and authenticity by promoting contemporary world values on Instagram.

Keywords: green products, gender equality, religious freedom, LGBTs, Instagram, netnography

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66 Impacts of Opium Addiction on Patterns of Angiographic Findings in Patients with Coronary Artery Syndrome

Authors: Alireza Abdiardekani, Maryam Salimi, Shirin Sarejloo, Mehdi Bazrafshan, Amir Askarinejad, Amirhossein Salimi, Hanieh Bazrafshan, Salar Javanshir, Armin Attar, Shokoufeh Khanzadeh, Mohsen Esmaeili, Hamed Bazrafshan Drissi

Abstract:

Background: Opium, after tobacco, is the most abused substance in the Middle East. The effects of opium use on coronary artery disease are indeed unclear. This study aimed to assess the association between opium use and angiographic findings in patients with acute coronary syndrome (ACS) diagnosis at Al-Zahra Heart Hospital, Shiraz, Iran. Methods: In this case-control study, 170 patients admitted for coronary angiography were enrolled from 2019 to 2020. They were categorized into two groups based on their history: "non-opium" and "opium." SPSS (Version 26) was used to investigate the correlation between opioid addiction and the severity of coronary artery disease. Results: The results of our study reveal that the mean age of the participants was 61.63±9.07. This study indicated that 49 (28.82%) patients were female, and 121 (71.17%) were male. Our findings revealed that three-vessel disease was more frequent in non-opium (40; 47.05%) and opium (45; 52.94%) groups. There was a significant correlation between the severity of the second diagonal artery(D2) and right coronary artery(RCA) involvement and opium consumption. There was a strong positive correlation between the location of the vascular lesion in the left circumflex artery and opium consumption. Conclusion: Opium, as an independent risk factor for cardiovascular diseases, can have specific effects on angiographic findings in patients with coronary artery disease. Public health officials and politicians should arrange several programs to increase the general population’s consciousness about opioid use and its consequences.

Keywords: acute coronary syndrome, opium, coronary artery disease, angiography

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65 Time-Domain Analysis Approaches of Soil-Structure Interaction: A Comparative Study

Authors: Abdelrahman Taha, Niloofar Malekghaini, Hamed Ebrahimian, Ramin Motamed

Abstract:

This paper compares the substructure and direct methods for soil-structure interaction (SSI) analysis in the time domain. In the substructure SSI method, the soil domain is replaced by a set of springs and dashpots, also referred to as the impedance function, derived through the study of the behavior of a massless rigid foundation. The impedance function is inherently frequency dependent, i.e., it varies as a function of the frequency content of the structural response. To use the frequency-dependent impedance function for time-domain SSI analysis, the impedance function is approximated at the fundamental frequency of the structure-soil system. To explore the potential limitations of the substructure modeling process, a two-dimensional reinforced concrete frame structure is modeled using substructure and direct methods in this study. The results show discrepancies between the simulated responses of the substructure and the direct approaches. To isolate the effects of higher modal responses, the same study is repeated using a harmonic input motion, in which a similar discrepancy is still observed between the substructure and direct approaches. It is concluded that the main source of discrepancy between the substructure and direct SSI approaches is likely attributed to the way the impedance functions are calculated, i.e., assuming a massless rigid foundation without considering the presence of the superstructure. Hence, a refined impedance function, considering the presence of the superstructure, shall be developed. This refined impedance function is expected to significantly improve the simulation accuracy of the substructure approach for structural systems whose behavior is dominated by the fundamental mode response.

Keywords: direct approach, impedance function, soil-structure interaction, substructure approach

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64 Orthogonal Metal Cutting Simulation of Steel AISI 1045 via Smoothed Particle Hydrodynamic Method

Authors: Seyed Hamed Hashemi Sohi, Gerald Jo Denoga

Abstract:

Machining or metal cutting is one of the most widely used production processes in industry. The quality of the process and the resulting machined product depends on parameters like tool geometry, material, and cutting conditions. However, the relationships of these parameters to the cutting process are often based mostly on empirical knowledge. In this study, computer modeling and simulation using LS-DYNA software and a Smoothed Particle Hydrodynamic (SPH) methodology, was performed on the orthogonal metal cutting process to analyze three-dimensional deformation of AISI 1045 medium carbon steel during machining. The simulation was performed using the following constitutive models: the Power Law model, the Johnson-Cook model, and the Zerilli-Armstrong models (Z-A). The outcomes were compared against the simulated results obtained by Cenk Kiliçaslan using the Finite Element Method (FEM) and the empirical results of Jaspers and Filice. The analysis shows that the SPH method combined with the Zerilli-Armstrong constitutive model is a viable alternative to simulating the metal cutting process. The tangential force was overestimated by 7%, and the normal force was underestimated by 16% when compared with empirical values. The simulation values for flow stress versus strain at various temperatures were also validated against empirical values. The SPH method using the Z-A model has also proven to be robust against issues of time-scaling. Experimental work was also done to investigate the effects of friction, rake angle and tool tip radius on the simulation.

Keywords: metal cutting, smoothed particle hydrodynamics, constitutive models, experimental, cutting forces analyses

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63 Eggshell Waste Bioprocessing for Sustainable Acid Phosphatase Production and Minimizing Environmental Hazards

Authors: Soad Abubakr Abdelgalil, Gaber Attia Abo-Zaid, Mohamed Mohamed Yousri Kaddah

Abstract:

Background: The Environmental Protection Agency has listed eggshell waste as the 15th most significant food industry pollution hazard. The utilization of eggshell waste as a source of renewable energy has been a hot topic in recent years. Therefore, finding a sustainable solution for the recycling and valorization of eggshell waste by investigating its potential to produce acid phosphatase (ACP) and organic acids by the newly-discovered B. sonorensis was the target of the current investigation. Results: The most potent ACP-producing B. sonorensis strain ACP2 was identified as a local bacterial strain obtained from the effluent of paper and pulp industries on basis of molecular and morphological characterization. The use of consecutive statistical experimental approaches of Plackett-Burman Design (PBD), and Orthogonal Central Composite Design (OCCD), followed by pH-uncontrolled cultivation conditions in a 7 L bench-top bioreactor, revealed an innovative medium formulation that substantially improved ACP production, reaching 216 U L⁻¹ with ACP yield coefficient Yp/x of 18.2 and a specific growth rate (µ) of 0.1 h⁻¹. The metals Ag+, Sn+, and Cr+ were the most efficiently released from eggshells during the solubilization process by B. sonorensis. The uncontrolled pH culture condition is the most suited and favored setting for improving the ACP and organic acids production simultaneously. Quantitative and qualitative analyses of produced organic acids were carried out using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Lactic acid, citric acid, and hydroxybenzoic acid isomer were the most common organic acids produced throughout the cultivation process. The findings of thermogravimetric analysis (TGA), differential scan calorimeter (DSC), scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), and X-Ray Diffraction (XRD) analysis emphasize the significant influence of organic acids and ACP activity on the solubilization of eggshells particles. Conclusions: This study emphasized robust microbial engineering approaches for the large-scale production of a newly discovered acid phosphatase accompanied by organic acids production from B. sonorensis. The biovalorization of the eggshell waste and the production of cost-effective ACP and organic acids were integrated into the current study, and this was done through the implementation of a unique and innovative medium formulation design for eggshell waste management, as well as scaling up ACP production on a bench-top scale.

Keywords: chicken eggshells waste, bioremediation, statistical experimental design, batch fermentation

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62 Protection of Steel Bars in Reinforce Concrete with Zinc Based Coverings

Authors: Hamed Rajabzadeh Gatabi, Soroush Dastgheibifard, Mahsa Asnafi

Abstract:

There is no doubt that reinforced concrete is known as one of the most significant materials which is used in construction industry for many years. Although, some natural elements in dealing with environment can contribute to its corrosion or failure. One of which is bar or so-called reinforcement failure. So as to combat this problem, one of the oxidization prevention methods investigated was the barrier protection method implemented over the application of an organic coating, specifically fusion-bonded epoxy. In this study comparative method is prepared on two different kinds of covered bars (zinc-riches epoxy and polyamide epoxy coated bars) and also uncoated bar. With the aim of evaluate these reinforced concretes, the stickiness, toughness, thickness and corrosion performance of coatings were compared by some tools like Cu/CuSo4 electrodes, EIS and etc. Different types of concretes were exposed to the salty environment (NaCl 3.5%) and their durability was measured. As stated by the experiments in research and investigations, thick coatings (named epoxies) have acceptable stickiness and strength. Polyamide epoxy coatings stickiness to the bars was a bit better than that of zinc-rich epoxy coatings; nonetheless it was stiffer than the zinc rich epoxy coatings. Conversely, coated bars with zinc-rich epoxy showed more negative oxidization potentials, which take revenge protection of bars by zinc particles. On the whole, zinc-rich epoxy coverings is more corrosion-proof than polyamide epoxy coatings due to consuming zinc elements and some other parameters, additionally if the epoxy coatings without surface defects are applied on the rebar surface carefully, it can be said that the life of steel structures is subjected to increase dramatically.

Keywords: surface coating, epoxy polyamide, reinforce concrete bars, salty environment

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61 Association between Eating Behavior in Children Aged 7-10 Years Old and Their Mother’s Feeding Practice: A Study among the Families in Isfahan, Iran

Authors: Behnaz Farahani, Razieh Sotoudeh, Ali Vahdani, Hamed Abdi

Abstract:

Individual differences in eating behavior can cause underweight or overweight and obesity. Thus influencing factors on children’s eating behavior such as mothers’ feeding practices are needed to be more investigated. The goals of this survey are to evaluate the association of (i) parental pressure and children’s food avoidant tendency, (ii) parental restriction and children’s food approach tendency, (iii) modeling of healthy eating in front of children and their children’s eating behavior. 760 mothers of children aged 7-10 from schools in Isfahan were asked to complete questionnaires including Child Feeding Questionnaire, Children’s Eating Behavior Questionnaire, Modeling Questionnaire, and self-administered demographic questionnaire in which mothers reported their children’s height and weight as well. Of those mothers, 745 completed the questionnaires for the children’s index (mean age: 8.513±1.112) during the 2011-2012 school year. The results of this quantitative, descriptive, cross-sectional analysis indicated that “parental restriction” was positively associated with child food responsiveness (P,0.000) and food enjoyment (P,0.000) and surprisingly, it was positively associated with Food Fussiness(0.000) .Parental pressure to eat was positively associated with child satiety responsiveness (P,0.000), slowness (P,0.000), and fussiness (P,0.00) and negatively associated with Food responsiveness(p,0.000)and Enjoyment of food (p,0.002), modeling of healthy eating were positively associated with Enjoyment of food / q (p,0.000) and negatively with food fussiness (P,0.000). The results of this survey will improve interventions and maternal guidance on their feeding practices and their association with children’s eating behavior and weight.

Keywords: feeding practices, eating behavior, pressure to eat, restriction, modeling, satiety responsiveness, slowness in eating, food fussiness, food responsiveness, enjoyment of food

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60 Experimental and Numerical Performance Analysis for Steam Jet Ejectors

Authors: Abdellah Hanafi, G. M. Mostafa, Mohamed Mortada, Ahmed Hamed

Abstract:

The steam ejectors are the heart of most of the desalination systems that employ vacuum. The systems that employ low grade thermal energy sources like solar energy and geothermal energy use the ejector to drive the system instead of high grade electric energy. The jet-ejector is used to create vacuum employing the flow of steam or air and using the severe pressure drop at the outlet of the main nozzle. The present work involves developing a one dimensional mathematical model for designing jet-ejectors and transform it into computer code using Engineering Equation solver (EES) software. The model receives the required operating conditions at the inlets and outlet of the ejector as inputs and produces the corresponding dimensions required to reach these conditions. The one-dimensional model has been validated using an existed model working on Abu-Qir power station. A prototype has been designed according to the one-dimensional model and attached to a special test bench to be tested before using it in the solar desalination pilot plant. The tested ejector will be responsible for the startup evacuation of the system and adjusting the vacuum of the evaporating effects. The tested prototype has shown a good agreement with the results of the code. In addition a numerical analysis has been applied on one of the designed geometry to give an image of the pressure and velocity distribution inside the ejector from a side, and from other side, to show the difference in results between the two-dimensional ideal gas model and real prototype. The commercial edition of ANSYS Fluent v.14 software is used to solve the two-dimensional axisymmetric case.

Keywords: solar energy, jet ejector, vacuum, evaporating effects

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59 Enhancement of Critical Temperature and Improvement of Mechanical Properties of Yttrium Barium Copper Oxide Superconductor

Authors: Hamed Rahmati

Abstract:

Nowadays, increasing demand for electric energy makes applying high-temperature superconductors inevitable. However, the most important problem of the superconductors is their critical temperature, which necessitates using a cryogenic system for keeping these substances’ temperatures lower than the critical level. Cryogenic systems used for this reason are not efficient enough, and keeping these large systems maintained is costly. Moreover, the low critical temperature of superconductors has delayed using them in electrical equipment. In this article, at first, characteristics of three superconductors, magnesium diboride (MgB2), yttrium barium copper oxide (YBCO), and iron-based superconductors (FeSC), have been analyzed and a new structure of YBCO superconductors is presented. Generally, YBCO (YBa2Cu7O2) has a weak mechanical structure. By introducing some changes in its configuration and adding one silver atom (Ag) to it, its mechanical characteristics improved significantly. Moreover, for each added atom, a star-form structure was introduced in which changing the location of Ag atom led to considerable changes in temperature. In this study, Ag has been added by applying two accurate methods named random and substitute ones. The results of both methods have been examined. It has been shown that adding Ag by applying the substitute method can improve the mechanical properties of the superconductor in addition to increasing its critical temperature. In the mentioned strategy (using the substitute method), the critical temperature of the superconductor was measured up to 99 Kelvin. This new structure is usable in designing superconductors’ rings to be applied in superconducting magnetic energy storage (SMES). It can also lead to a reduction in the cryogenic system size, a decline in conductor wastes, and a decrease in costs of the whole system.

Keywords: critical temperature, cryogenic system, high-temperature superconductors, YBCO

Procedia PDF Downloads 150