Search results for: long term effect

Authors: Myoungsoon You, Heejung Son

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During a pandemic, hospital workers should protect not only their vulnerable patients but also themselves from the consequences of rapidly spreading infection. However, the evidence on the psychological impact of an outbreak on hospital workers is limited. In this study, we aim to assess hospital workers’ psychological well-being and function at the workplace after an outbreak, by focusing on ‘psychological resilience’. Specifically, the effects of risk appraisal, emotional experience, and coping ability on resilience indicated by the likelihood of post-traumatic syndrome disorder and willingness to work were investigated. Such role and position of each factor were analyzed using a path model, and the result was compared between the healthcare worker and non-healthcare worker groups. In the investigation, 280 hospital workers who experienced the 2015 Middle East Respiratory Syndrome outbreak in South Korea have participated. The result presented, in both groups, the role of the appraisal of risk and coping ability appeared consistent with a previous research, that was, the former interrupted resilience while the latter facilitated it. In addition, the role of emotional experience was highlighted as, in both groups, emotional disruption not only directly associated with low resilience but mediated the effect of perceived risk on resilience. The differences between the groups were also identified, which were, the role of emotional experience and coping ability was more prominent in the non-HCW group in explaining resilience. From the results, implications on how to support hospital personnel during an outbreak in a way to facilitate their resilience after the outbreak were drawn.

Keywords: hospital workers, emotions, infectious disease outbreak, psychological resilience

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Authors: Ruben Dario Tovar-Valencia, Eshan Ganju, Fei Han, Monica Prezzi, Rodrigo Salgado

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Particle breakage occurs even in strong silica sand particles. There is compelling evidence that suggests that particle breakage causes changes in several properties such as permeability, peak strength, dilatancy and critical state friction angle. Current pile design methods that are based on soil properties do not account for particle breakage that occurs during driving or jacking of displacement piles. This may lead to significant overestimation of pile capacity in sands dominated by particles susceptible to breakage, such as carbonate sands. The objective of this paper is to study the influence of shear displacement on particle breakage and friction angle of carbonate sands, and to furthermore quantify the change in friction angle observed with different levels of particle breakage. To study the phenomenon of particle breakage, multiple ring shear tests have been performed at different levels of vertical confinement on a thoroughly characterized carbonate sand to find i) the shear displacement necessary to reach stable friction angles and ii) the effect of particle breakage on the mobilized friction angle of the tested sand. The findings of this study can potentially be used to update the current pile design methods by developing a friction angle which is a function of shear displacement and breakage characteristics of the sand instead of being a constant value.

Keywords: breakage, carbonate sand, friction angle, pile design, ring shear test

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Authors: Jui-Pui Hung, Yu-Sheng Lai, Tzuo-Liang Luo, Kung-Da Wu, Yun-Ji Zhan

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This study presented the investigation of the influence of the tool holder interface stiffness on the dynamic characteristics of a spindle tool system. The interface stiffness was produced by drawbar force on the tool holder, which tends to affect the spindle dynamics. In order to assess the influence of interface stiffness on the vibration characteristic of spindle unit, we first created a three dimensional finite element model of a high speed spindle system integrated with tool holder. The key point for the creation of FEM model is the modeling of the rolling interface within the angular contact bearings and the tool holder interface. The former can be simulated by a introducing a series of spring elements between inner and outer rings. The contact stiffness was calculated according to Hertz contact theory and the preload applied on the bearings. The interface stiffness of the tool holder was identified through the experimental measurement and finite element modal analysis. Current results show that the dynamic stiffness was greatly influenced by the tool holder system. In addition, variations of modal damping, static stiffness and dynamic stiffness of the spindle tool system were greatly determined by the interface stiffness of the tool holder which was in turn dependent on the draw bar force applied on the tool holder. Overall, this study demonstrates that identification of the interface characteristics of spindle tool holder is of very importance for the refinement of the spindle tooling system to achieve the optimum machining performance.

Keywords: dynamic stiffness, spindle-tool holder, interface stiffness, drawbar force

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Authors: Soham Lalwala, Ronita Singh, Yaman Pattanaik

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In the present scenario of globalization and privatization, it becomes difficult for small scale industries to sustain due to rapidly increasing competition. In a developing country, most of the gross output is generally obtained from small scale industries. Thus, quality plays a vital role in maintaining customer satisfaction. Total quality management (TQM) is an approach which enables employees to focus on quality rather quantity, further improving the competitiveness, effectiveness and flexibility of the whole organization. The objective of the paper is to present the application of TQM and develop a TQM Model in a small scale industry of narrow fabrics in Surat, India named ‘Rajdhani Lace & Borders’. Further, critical success factors relating all the fabric processes involved were identified. The data was collected by conducting a questionnaire survey. After data was collected, critical areas were visualized using different tools of TQM such as cause and effect diagram, control charts and run charts. Overall, responses were analyzed, and factor analysis was used to develop the model. The study presented here will aid the management of the above-mentioned industry in identifying the weaker areas and thus give a plausible solution to improve the total productivity of the firm along with effective utilization of resources and better customer satisfaction.

Keywords: critical success factors, narrow fabrics, quality, small scale industries, total quality management (TQM)

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Authors: Behrooz Ataee, Mohammad Golzar

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The main purpose of using side by side (SBS) hybrid yarn in pultrusion thermoplastic method is reprisal the effect of high viscosity in melted thermoplastic and reduction of distance between reinforced fiber and melted thermoplastic. SBS hybrid fiber yarn composed of thermoplastic fibers and fiber reinforcement should be produced in the preparation of pultruded thermoplastic composites prepreg to reach better impregnation. An experimental set-up was designed and built to pultrude continues polypropylene and glass fiber to get obtain a suitable impregnated round prepregs. In final stage, the round prepregs come together to produce rectangular profile. Higher fiber volume fraction produces higher void volume fraction, however the second stage of the production process of rectangular profile and the cold die decrease 50% of the void volume fraction. Results show that whit increasing void volume fraction, flexural and shear strength decrease. Also, under certain conditions of parameters the pultruded profiles exhibit better flexural and shear strength. The pulling speed seems to have the greatest influence on the profile quality. In addition, adding cold die strongly increases the surface quality of rectangular profile.

Keywords: thermoplastic pultrusion, hybrid pultrusion, side-by-side fibers, impregnation

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Authors: Suparna Roy, P. Anantharaman

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The aim of this work is to estimate some in-vitro antioxidant activities and total phenols of various extracts such as aqueous, acetone, ethanol, methanol extract of seaweeds and pigments content by Spectrophotometric method. The seaweeds were collected during 2016 from Rameshwaram, southeast coast of India. Among four different extracts, aqueous extracts from all seaweeds had minimum activity than acetone, methanol and ethanol. The Rhodophyta and Phaeophyta had high antioxidant activity in comparing to Chlorophyta. The highest total antioxidant activity was found in acetone extract fromTurbinaria decurrens (98.97±0.00%), followed by its methanol extract (98.81±0.60%) and ethanol extract (98.58±0.53%). The highest reducing power and H2O2 scavenging activity were found in acetone extract of Caulerpa racemosa (383.25±1.04%), and methanol extract from Caulerpa racemosa var. macrophysa (24.91±0.49%). The methanol extract from Caulerpa scalpelliformis contained the highest total phenol (85.23±0.12%). The Chloro-a and Chloro-b contents were the highest in Gracilaria foliifera (13.69±0.38% mg/gm dry wt.) and Caulerpa racemosa var. macrophysa (9.12 ±0.12% mg/gm dry wt.) likewise carotenoid was also the highest in Gracilaria foliifera (0.054±0.0003% mg/gm dry wt.) and Caulerpa racemosa var. macrophysa (0.04 ±0.002% mg/gm dry wt.). It can be concluded from this study that some seaweed extract can be used for natural antioxidant production, after further characterization to negotiate the side effect of synthetic, market available antioxidants.

Keywords: seaweeds, antioxidant, total phenol, pigment, Olaikuda, Vadakkadu, Rameshwaram

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Authors: Zhaohan Xie, Yining Yu, Mingliang Chen

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As research has shown a convergent tendency for aversion to AI recommendation, it is imperative to find a way to promote AI usage and better harness the technology. In the context of e-commerce, this study has found evidence that people show less avoidance of algorithms when recommending search products compared to experience products. This is due to people’s different attribution of mind to AI versus humans, as suggested by mind perception theory. While people hold the belief that an algorithm owns sufficient capability to think and calculate, which makes it competent to evaluate search product attributes that can be obtained before actual use, they doubt its capability to sense and feel, which is essential for evaluating experience product attributes that must be assessed after experience in person. The result of the behavioral investigation (Study 1, N=112) validated that consumers show low purchase intention to experience products recommended by AI. Further consumer neuroscience study (Study 2, N=26) using Event-related potential (ERP) showed that consumers have a higher level of cognitive conflict when faced with AI recommended experience product as reflected by larger N2 component, while the effect disappears for search product. This research has implications for the effective employment of AI recommenders, and it extends the literature on e-commerce and marketing communication.

Keywords: algorithm recommendation, consumer behavior, e-commerce, event-related potential, experience product, search product

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Authors: Hilal Köse, Şeyma Dombaycıoğlu, Ali Osman Aydın, Hatem Akbulut

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Rechargeable lithium-ion batteries (LIBs) have become promising power sources for a wide range of applications, such as mobile communication devices, portable electronic devices and electrical/hybrid vehicles due to their long cycle life, high voltage and high energy density. Graphite, as anode material, has been widely used owing to its extraordinary electronic transport properties, large surface area, and high electrocatalytic activities although its limited specific capacity (372 mAh g-1) cannot fulfil the increasing demand for lithium-ion batteries with higher energy density. To settle this problem, many studies have been taken into consideration to investigate new electrode materials and metal oxide/graphene composites are selected as a kind of promising material for lithium ion batteries as their specific capacities are much higher than graphene. Among them, SnO₂, an n-type and wide band gap semiconductor, has attracted much attention as an anode material for the new-generation lithium-ion batteries with its high theoretical capacity (790 mAh g-1). However, it suffers from large volume changes and agglomeration associated with the Li-ion insertion and extraction processes, which brings about failure and loss of electrical contact of the anode. In addition, there is also a huge irreversible capacity during the first cycle due to the formation of amorphous Li₂O matrix. To obtain high capacity anode materials, we studied on the synthesis and characterization of SnO₂-Graphene nanocomposites and investigated the capacity of this free-standing anode material in this work. For this aim, firstly, graphite oxide was obtained from graphite powder using the method described by Hummers method. To prepare the nanocomposites as free-standing anode, graphite oxide particles were ultrasonicated in distilled water with SnO2 nanoparticles (1:1, w/w). After vacuum filtration, the GO-SnO₂ paper was peeled off from the PVDF membrane to obtain a flexible, free-standing GO paper. Then, GO structure was reduced in hydrazine solution. Produced SnO2- graphene nanocomposites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD) analyses. CR2016 cells were assembled in a glove box (MBraun-Labstar). The cells were charged and discharged at 25°C between fixed voltage limits (2.5 V to 0.2 V) at a constant current density on a BST8-MA MTI model battery tester with 0.2C charge-discharge rate. Cyclic voltammetry (CV) was performed at the scan rate of 0.1 mVs-1 and electrochemical impedance spectroscopy (EIS) measurements were carried out using Gamry Instrument applying a sine wave of 10 mV amplitude over a frequency range of 1000 kHz-0.01 Hz.

Keywords: SnO₂-graphene, nanocomposite, anode, Li-ion battery

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Authors: Evelyn Kropfreiter, Roland Bernhard

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There has been an increased interest in school-based whole-child development in the Austrian education system in the last few years. Although there is a consensus among academics that teachers' beliefs are an essential component of their professional competence, there are hardly any studies in the German-speaking world examining teachers' beliefs about school-based character education. To close this gap, we are conducting a mixed methods study combining qualitative interviews and a questionnaire in Austria (doctoral thesis at the University of Salzburg). In this paper, we present preliminary insights into the quantitative strand of the project. In contrast to German-speaking countries, the Anglo-Saxon world has a long tradition of explicit character education in schools. There has been a rising interest in approaches focusing on a neo-Aristotelian form of character education in England. The Jubilee Centre strongly influences the "renaissance" of papers on neo-Aristotelian character education for Character and Virtues, founded in 2012. The quantitative questionnaire study (n = 264) is an online survey of teachers and school principals conducted in four different federal states in spring 2023. Most respondents (n = 264) from lower secondary schools (AHS-Unterstufe and Mittelschule) believe that character education in schools for 10-14-year-olds is more important for society than good exam results. Many teachers state that they consider themselves prepared to promote their students' personal development and life skills through their education and to attend further training courses. However, there are many obstacles in the education system to ensure that a comprehensive education reaches the students. Many teachers state that they consider themselves prepared to promote their students' character strengths and life skills through their education and to attend further training courses. However, there are many obstacles in the education system to ensure that a comprehensive education reaches the students. Among the most cited difficulties, teachers mention the time factor associated with an overcrowded curriculum and a strong focus on performance, which often leaves them needing more time to keep an eye on nurturing the whole person. The fact that character education is not a separate subject, and its implementation needs to be monitored also makes it challenging to implement it in everyday school life. Austrian teachers prioritize moral virtues such as compassion and honesty as character strengths in everyday school life and resilience and commitment in the next place. Our results are like those reported in other studies on teacher's beliefs about character education. They indicate that Austrian teachers want to teach character in their schools but see systemic constraints such as the curriculum, in which personality roles play a subordinate role, and the focus on performance testing in the school system and the associated lack of time as obstacles to fostering more character development in students.

Keywords: character education, life skills, teachers' beliefs, virtues

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Authors: Nathaniel Oladimeji Dixon, Adekemi Dorcas Fadun

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Educational managers have observed a downward trend in the administrative effectiveness of non-teaching staff in federal universities in South-west Nigeria. This is evident in the low-quality service delivery of administrators and unaccomplished institutional goals and missions of higher education. Scholars have thus indicated the need for the deployment and adoption of a practice that encourages information collection and sharing among stakeholders with a view to improving service delivery and outcomes. This study examined the extent to which knowledge management correlated with the administrative effectiveness of non-teaching staff in federal universities in South-west Nigeria. The study adopted the survey design. Three federal universities (the University of Ibadan, Federal University of Agriculture, Abeokuta, and Obafemi Awolowo University) were purposively selected because administrative ineffectiveness was more pronounced among non-teaching staff in government-owned universities, and these federal universities were long established. The proportional and stratified random sampling was adopted to select 1156 non-teaching staff across the three universities along the three existing layers of the non-teaching staff: secretarial (senior=311; junior=224), non-secretarial (senior=147; junior=241) and technicians (senior=130; junior=103). Knowledge Management Practices Questionnaire with four sub-scales: knowledge creation (α=0.72), knowledge utilization (α=0.76), knowledge sharing (α=0.79) and knowledge transfer (α=0.83); and Administrative Effectiveness Questionnaire with four sub-scales: communication (α=0.84), decision implementation (α=0.75), service delivery (α=0.81) and interpersonal relationship (α=0.78) were used for data collection. Data were analyzed using descriptive statistics, Pearson product-moment correlation and multiple regression at 0.05 level of significance, while qualitative data were content analyzed. About 59.8% of the non-teaching staff exhibited a low level of knowledge management. The indices of administrative effectiveness of non-teaching staff were rated as follows: service delivery (82.0%), communication (78.0%), decision implementation (71.0%) and interpersonal relationship (68.0%). Knowledge management had significant relationships with the indices of administrative effectiveness: service delivery (r=0.82), communication (r=0.81), decision implementation (r=0.80) and interpersonal relationship (r=0.47). Knowledge management had a significant joint prediction on administrative effectiveness (F (4;1151)= 0.79, R=0.86), accounting for 73.0% of its variance. Knowledge sharing (β=0.38), knowledge transfer (β=0.26), knowledge utilization (β=0.22), and knowledge creation (β=0.06) had relatively significant contributions to administrative effectiveness. Lack of team spirit and withdrawal syndrome is the major perceived constraints to knowledge management practices among the non-teaching staff. Knowledge management positively influenced the administrative effectiveness of the non-teaching staff in federal universities in South-west Nigeria. There is a need to ensure that the non-teaching staff imbibe team spirit and embrace teamwork with a view to eliminating their withdrawal syndromes. Besides, knowledge management practices should be deployed into the administrative procedures of the university system.

Keywords: knowledge management, administrative effectiveness of non-teaching staff, federal universities in the south-west of nigeria., knowledge creation, knowledge utilization, effective communication, decision implementation

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Authors: M. Sohrabi Narciss

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Urban spaces of Tehran, the capital of Iran, have witnessed many revolts, movements, and protests during the past few decades. After the Iranian Constitutional Revolution, the 1979 Revolution has had a profound impact on Tehran’s urban space. In 1979, the world watched as Iranians demonstrated en masse against the Pahlavi dynastdy which eventually led to its overthrow. Tehran’s public space is replete with images and artwork that depict the overthrow of the Pahlavi regime and the establishment of an Islamic government in Iran. The public artworks related to the 1979 Islamic Revolution reflect the riots, protests, and strikes that the Iranians underwent during the revolution. Many of these artworks try to revitalize the events that occurred in the 1970s by means of collective memory. Almost 4 decades have passed since the revolution and ever since the public artwork has been affected either directly or indirectly by the Iran-Iraq War, the Green Movement, and the rise and fall of various political forces. The present study is an attempt to investigate Tehran’s urban artwork such as urban sculptures and mural paintings organized and supervised by the government and the graffiti drawn by the critics or the opposition groups. To this end, in addition to the available documents, field research and questionnaires were used to qulaitatively analyze the data. This paper tries to address the following questions: 1) what changes have occurred in Tehran’s urban art? 2) Does the public, revolution-related artwork have an effect on people’s vitality? 3) do Iranians find these artworks appealing or not?

Keywords: public space, Tehran, public art, movement, Islamic revolution

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Authors: Kayijuka Idrissa

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This work investigates a mathematical study for traffic flow and traffic density in Kigali city roads and the data collected from the national police of Rwanda in 2012. While working on this topic, some mathematical models were used in order to analyze and compare traffic variables. This work has been carried out on Kigali roads specifically at roundabouts from Kigali Business Center (KBC) to Prince House as our study sites. In this project, we used some mathematical tools to analyze the data collected and to understand the relationship between traffic variables. We applied the Poisson distribution method to analyze and to know the number of accidents occurred in this section of the road which is from KBC to Prince House. The results show that the accidents that occurred in 2012 were at very high rates due to the fact that this section has a very narrow single lane on each side which leads to high congestion of vehicles, and consequently, accidents occur very frequently. Using the data of speeds and densities collected from this section of road, we found that the increment of the density results in a decrement of the speed of the vehicle. At the point where the density is equal to the jam density the speed becomes zero. The approach is promising in capturing sudden changes on flow patterns and is open to be utilized in a series of intelligent management strategies and especially in noncurrent congestion effect detection and control.

Keywords: statistical methods, traffic flow, Poisson distribution, car moving technics

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Authors: Hakeem Ade Omokayode Idowu

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The extent of the role played by human capabilities developments as well as knowledge management on employees’ performance in the nuclear energy sector of Nigeria remains unclear. This is in view of the important role which human resource capabilities could play in the desire to generate energy using nuclear resources. This study appraised the extent of human resource capabilities available in the nuclear energy sector of Nigeria. It further examined the relationship between knowledge management and employees’ performance in the nuclear energy sector. The study adopted a descriptive research design with a population that comprised all the 1736 members of staff of the selected centres, institutes, and the headquarters of the Nigeria Atomic Energy Commission (NAEC), Nigerian Nuclear Regulatory Authority (NNRA), and Energy Commission of Nigeria (ECN) and a sample size of 332 employees was selected using purposive and convenience sampling techniques. Data collected were subjected to analysis using frequency counts and simple regression. The results showed that majority of the employees perceived that they have to a high extent of availability of knowledge (118, 35.5%), credibility (134, 40.4%), alignment (130, 39.2%), performance (126, 38%) and innovation (138, 41.6%) The result of the hypothesis tested indicated that knowledge management has a positive and significant effect on employees’ performance (Beta weight = 0.336, R2 =0.113, F-value = 41.959, p-value = 0.000< 0.05). The study concluded that human resource capabilities and knowledge management could enhance employee performance within the nuclear energy sector of Nigeria.

Keywords: human resource capabilities, knowledge management, employees productivity, national development

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Authors: Mohammad Koushafar, Amir Hossein Khoshgoftarmanesh

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Due to water shortage, application of saline water for irrigation is an urgent requirement in agriculture. Thus, this study, the effect of calcium and potassium application as additive in saline root media for reduce salinity adverse effects was investigated on tomato growth in a hydroponic system with unequal distribution of salts in the root media, which was divided into two equal parts containing full Johnson nutrient solution and 40 mM NaCl solution, alone or in combination with KCl (6 mM), CaCl2 (4 mM), K+Ca (3+2 mM) or half-strength Johnson nutrient solution. The root splits were exchanged every 7 days. Results showed that addition of calcium, calcium-potassium and nutrition elements equivalent to half the concentration of Johnson formula to the saline-half of culture media minimized the reduction in plant growth caused by NaCl, although the addition of potassium to culture media was not effective. The greatest concentration of sodium was observed at the shoot of treatments which had the smallest growth. According to the results of this study, in the case of dynamic and non-uniform distribution of salts in the root media, by the addition of additive to the saline solution, it would be possible to use of saline water with no significant growth reduction.

Keywords: calcium, hydroponic, local salinity, potassium, salin water, tomato

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Authors: Sawale Pravin Digambar, G. R. Patil, Shaik Abdul Hussain

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Terminalia arjuna (TA), an important medicinal plant in Indian System of Medicine, is specifically recognized for its recuperative effect on heart ailments. Alcoholic extract of TA (both free and encapsulated) was incorporated into milk to obtain functional dairy beverages. The respective beverages were appropriately flavored and optimized using response surface methodology to improve the sensory appeal. The beverages were evaluated for their compositional, anti-oxidative and various other physico-chemical aspects. Addition of herb (0.3%) extract to flavoured dairy drink (Drink 1) resulted in significantly lowered (p>0.05) HMF content and increased antioxidant activity, total phenol content as compared with control (Control 1). Subsequently, a significant (p>0.05) increase in acidity and sedimentation was also observed. Encapsulated herb (1.8%) incorporated drink (Drink 2) had significantly (P>0.05) enhanced HMF value and decreased antioxidant activity, phenol content as compared to herb added vanilla chocolate dairy drink (Drink 1). It can be concluded that addition of encapsulated TA extract and non-encapsulated TA extract to chocolate dairy drink at 0.3% concentration altered the functional properties vanilla chocolate dairy drink which could be related to the interaction of herb components such as polyphenol with milk protein or maltodextrin/ gum Arabic matrix.

Keywords: Terminalia arjuna, encapsulate, antioxidant activity, physicochemical study

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Authors: Javeria Ahmad, Ayesha Maryam, Zahid Rizwan, Nadeem Nasir, Yasir Nawab, Hafiz Shehbaz Ahmad

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Mitigation of electromagnetic interference (EMI) through thin, lightweight, and cost-effective materials is critical for electronic appliances as well as human health. The present research work discusses the design of composites that are suitable to minimize EMI through various stacking sequences. The carbon fibers reinforced composite structures impregnated with dielectric (MWCNTs) and magnetic nanofillers (Fe₂O₃) were developed to investigate their microwave absorption properties. The composite structure comprising a single type of nanofillers, each of MWCNTs & Fe₂O₃, was developed, and then their layers were stacked over each other with various stacking sequences to investigate the best stacking sequence, which presents good microwave absorption characteristics. A vector network analyzer (VNA) was used to analyze the microwave absorption properties of these developed composite structures. The composite structures impregnated with the layers of a dielectric nanofiller and sandwiched between the layers of a magnetic nanofiller show the highest EMI shielding value of 59 dB and a dielectric conductivity of 35 S/cm in the frequency range of 0.1 to 13.6 GHz. The results also demonstrate that the microwave absorption properties of the developed composite structures were dominant over reflection properties. The absence of an external peak in X-ray diffraction (XRD), marked the purity of the added nanofillers.

Keywords: nanocomposites, microwave absorption, EMI shielding, skin depth, reflection loss

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Authors: Muna A. Eissawi, Safaa Abed Elfataah, Haytham Hago, Fatima E Abukunna, Ibtisam Amin Goreish, Nahid Gornas

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The study examined and analyzed the genetic diversity of DRB1locus of exon 2 of major histocompatibility complex of Sudanese desert sheep using PCR-RFLP and DNA sequencing. Five hundred samples belonging to five ecotypes of Desert Sudanese sheep (Abrag (Ab), Ashgar (Ash), Hamari (H), Kabashi (K) and Watish (W) were included. Amplification of exon 2 of the DRB1 gene yielded (300bp) amplified product in different ecotypes. Nine different digestion patterns corresponding to Five distinct alleles were observed with Rsa1 digestion. Genotype (ag) was the most common among all ecotypes, with a percentage comprised (40.4 %). The Hardy-Weinberg equilibrium (HWE) test showed that the studied ecotypes have significantly deviated from the theoretical proportions of Rsa1 patterns; probability values of the Chi-square test for HWE for MHC-DRB1 gene in SDS were 0.00 in all ecotypes. The constructed phylogenetic tree revealed the relation of 22 Sudanese isolates with each other and showed the shared sequences with 47 published foreign sequences randomly selected from different geographic regions. The results of this study highlight the effect of heterozygosity of MHC genes of the Desert sheep of Sudan which may clarify some of genetic back ground of their disease resistance and adaptation to environment.

Keywords: desert sheep, MHC, Ovar-DRB1, polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP)

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Authors: Yanxue Shang, Jingbin Zeng

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Chlorobenzene homologues (CBHs) are a category of environmental pollutants that can not be ignored. They can stay in the environment for a long period and are potentially carcinogenic. The traditional degradation method of CBHs is dechlorination followed by sample preparation and analysis. This is not only time-consuming and laborious, but the detection and analysis processes are used in conjunction with large-scale instruments. Therefore, this can not achieve rapid and low-cost detection. Compared with traditional sensing methods, colorimetric sensing is simpler and more convenient. In recent years, chromaticity sensors based on fluorescence have attracted more and more attention. Compared with sensing methods based on changes in fluorescence intensity, changes in color gradients are easier to recognize by the naked eye. Accordingly, this work proposes to use single drop microextraction (SDME) technology to solve the above problems. After the dechlorination reaction was completed, the organic droplet extracts Cl⁻ and realizes fluorescence colorimetric sensing at the same time. This method was integrated sample processing and visual in-situ detection, simplifying the detection process. As a fluorescence colorimetric sensor material, CsPbBr₃ was encapsulated in MOF-5 to construct CsPbBr₃@MOF-5 fluorescence colorimetric composite. Then the fluorescence colorimetric sensor was constructed by dispersing the composite in SDME organic droplets. When the Br⁻ in CsPbBr₃ exchanges with Cl⁻ produced by the dechlorination reactions, it is converted into CsPbCl₃. The fluorescence color of the single droplet of SDME will change from green to blue emission, thereby realizing visual observation. Therein, SDME can enhance the concentration and enrichment of Cl⁻ and instead of sample pretreatment. The fluorescence color change of CsPbBr₃@MOF-5 can replace the detection process of large-scale instruments to achieve real-time rapid detection. Due to the absorption ability of MOF-5, it can not only improve the stability of CsPbBr₃, but induce the adsorption of Cl⁻. Simultaneously, accelerate the exchange of Br- and Cl⁻ in CsPbBr₃ and the detection process of Cl⁻. The absorption process was verified by density functional theory (DFT) calculations. This method exhibits exceptional linearity for Cl⁻ in the range of 10⁻² - 10⁻⁶ M (10000 μM - 1 μM) with a limit of detection of 10⁻⁷ M. Whereafter, the dechlorination reactions of different kinds of CBHs were also carried out with this method, and all had satisfactory detection ability. Also verified the accuracy by gas chromatography (GC), and it was found that the SDME we developed in this work had high credibility. In summary, the in-situ visualization method of dechlorination reaction detection was a combination of sample processing and fluorescence colorimetric sensing. Thus, the strategy researched herein represents a promising method for the visual detection of dechlorination reactions and can be extended for applications in environments, chemical industries, and foods.

Keywords: chlorobenzene homologues, colorimetric sensor, metal halide perovskite, metal-organic frameworks, single drop microextraction

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Authors: Rafal Michalski, Jakub Zygadlo

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We present the concept and scientific methods and algorithms of our computation system called ATOMIC MATTERS. This is the first presentation of the new computer package, that allows its user to describe physical properties of atomic localized electron systems subject to electromagnetic interactions. Our solution applies to situations where an unclosed electron 2p/3p/3d/4d/5d/4f/5f subshell interacts with an electrostatic potential of definable symmetry and external magnetic field. Our methods are based on Crystal Electric Field (CEF) approach, which takes into consideration the electrostatic ligands field as well as the magnetic Zeeman effect. The application allowed us to predict macroscopic properties of materials such as: Magnetic, spectral and calorimetric as a result of physical properties of their fine electronic structure. We emphasize the importance of symmetry of charge surroundings of atom/ion, spin-orbit interactions (spin-orbit coupling) and the use of complex number matrices in the definition of the Hamiltonian. Calculation methods, algorithms and convention recalculation tools collected in ATOMIC MATTERS were chosen to permit the prediction of magnetic and spectral properties of materials in isostructural series.

Keywords: atomic matters, crystal electric field (CEF) spin-orbit coupling, localized states, electron subshell, fine electronic structure

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Authors: Andrey V. Malyshev, Anna B. Petrova, Anatoly P. Surzhikov

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The article presents the results of the influence of diamagnetic additives on the defects level of ferrite ceramics. For this purpose, we use a previously developed method based on the mathematical analysis of experimental temperature dependences of the initial permeability. A phenomenological expression for the description of such dependence was suggested and an interpretation of its main parameters was given. It was shown, that the main criterion of the integral defects level of ferrite ceramics is the relation of two parameters correlating with elastic stress value in a material. Model samples containing a controlled number of intergranular phase inclusions served to prove the validity of the proposed method, as well as to assess its sensitivity in comparison with the traditional XRD (X-ray diffraction) analysis. The broadening data of diffraction reflexes of model samples have served for such comparison. The defects level data obtained by the proposed method are in good agreement with the X-ray data. The method showed high sensitivity. Therefore, the legitimacy of the selection relationship β/α parameters of phenomenological expression as a characteristic of the elastic state of the ferrite ceramics confirmed. In addition, the obtained data can be used in the detection of non-magnetic phases and testing the optimal sintering production technology of soft magnetic ferrites.

Keywords: cure point, initial permeability, integral defects level, homogeneity

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Authors: Mei-Ying Huang, Huei-Jen Ju, Liang-Wei Tseng, Chin-Jung Hsu

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The aim of this study was to investigate a probiotic, Leuconostoc mesenteroides B4, and its products, isomaltooligosaccharide and dextran, on growth performance, digestive enzymes, immune responses, and pathogen resistance of spotted grouper Epinephelus coioides. The grouper were fed control and diets supplemented with L. mesenteroides B4 (107 CFU/g), isomaltooligosaccharide (0.15%), isomaltooligosaccharide (0.15%) + L. mesenteroides B4 (107 CFU/g) (I + B4), and dextran (0.15%) + L. mesenteroides B4 (107 CFU/g) (D + B4) for 8 weeks. The result showed that final weights and percent weight gains of the grouper fed diets supplemented with L. mesenteroides B4 and I + B4 were significantly higher than that of the control group (p < 0.05). The activities of digestive enzymes in the grouper fed with I + B4 were significantly higher than the control group (p < 0.05), too. After challenge with Vibrio harveyi, the enzyme activities of antiprotease and lysozyme as well as of respiratory burst of the fish fed with I + B4 and D + B4 were significantly higher than that of the control group (p < 0.05). The grouper fed with the both diets also had higher survival rates than that of the control group after the challenge. Overall, the study indicated that feeding diets supplemented with L. mesenteroides B4, and its products, isomaltooligosaccharide, and dextran could be an effective method for enhancing the growth performance and disease resistance in orange-spotted grouper.

Keywords: orange-spotted grouper, probiotic Leuconostoc mesenteroides B4, isomaltooligosaccharide, dextran, growth performance, pathogen resistance

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Authors: Ritika Chaturvedi

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Introduction: Sexual objectification, characterized by the reduction of an individual to a mere object of sexual desire, remains a pervasive societal issue with profound repercussions on individual well-being. Such experiences, often rooted in systemic and cultural norms, have long-lasting implications for mental and emotional health. This study aims to explore the intricate relationship between experiences of sexual objectification and insidious trauma, further investigating the potential moderating effects of overexcitability as proposed by Dabrowski's theory of positive disintegration. Methodology: The research involved a comprehensive cohort of 204 women, spanning ages from 18 to 65 years. Participants were tasked with completing self-administered questionnaires designed to capture their experiences with sexual objectification. Additionally, the questionnaire assessed symptoms indicative of insidious trauma and explored overexcitability across five distinct domains: emotional, intellectual, psychomotor, sensory, and imaginational. Employing advanced statistical techniques, including multiple regression and moderation analysis, the study sought to decipher the intricate interplay among these variables. Findings: The study's results revealed a compelling positive correlation between experiences of sexual objectification and the onset of symptoms indicative of insidious trauma. This correlation underscores the profound and detrimental effects of sexual objectification on an individual's psychological well-being. Interestingly, the moderation analyses introduced a nuanced understanding, highlighting the differential roles of various overexcitability. Specifically, emotional, intellectual, and sensual overexcitability were found to exacerbate trauma symptomatology. In contrast, psychomotor overexcitability emerged as a protective factor, demonstrating a mitigating influence on the relationship between sexual objectification and trauma. Implications: The study's findings hold significant implications for a diverse array of stakeholders, encompassing mental health practitioners, educators, policymakers, and advocacy groups. The identified moderating effects of overexcitability emphasize the need for tailored interventions that consider individual differences in coping and resilience mechanisms. By recognizing the pivotal role of overexcitability in modulating the traumatic consequences of sexual objectification, this research advocates for the development of more nuanced and targeted support frameworks. Moreover, the study underscores the importance of continued research endeavors to unravel the intricate mechanisms and dynamics underpinning these relationships. Such endeavors are crucial for fostering the evolution of informed, evidence-based interventions and strategies aimed at mitigating the adverse effects of sexual objectification and promoting holistic well-being.

Keywords: sexual objectification, insidious trauma, emotional overexcitability, intellectual overexcitability, sensual overexcitability, psychomotor overexcitability, imaginational overexcitability

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Authors: Rashid S. Mohammad, Shicheng Zhang, Sun Lu, Syed Jamal-Ud-Din, Xinzhe Zhao

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A compositional reservoir simulation model (CMG-GEM) was used for cyclic CO₂ injection process in unconventional tight reservoir. Cyclic CO₂ injection is an enhanced oil recovery process consisting of injection, shut-in, and production. The study of cyclic CO₂ injection and hydrocarbon recovery in ultra-low permeability reservoirs is mainly a function of rock, fluid, and operational parameters. CMG-GEM was used to study several design parameters of cyclic CO₂ injection process to distinguish the parameters with maximum effect on the oil recovery and to comprehend the behavior of cyclic CO₂ injection in tight reservoir. On the other hand, permeability reduction induced by asphaltene precipitation is one of the major issues in the oil industry due to its plugging onto the porous media which reduces the oil productivity. In addition to asphaltene deposition, solubility of CO₂ in the aquifer is one of the safest and permanent trapping techniques when considering CO₂ storage mechanisms in geological formations. However, the effects of the above uncertain parameters on the process of CO₂ enhanced oil recovery have not been understood systematically. Hence, it is absolutely necessary to study the most significant parameters which dominate the process. The main objective of this study is to improve techniques for designing cyclic CO₂ injection process while considering the effects of asphaltene deposition and solubility of CO₂ in the brine in order to prevent asphaltene precipitation, minimize CO₂ emission, optimize cyclic CO₂ injection, and maximize oil production.

Keywords: tight reservoirs, cyclic O₂ injection, asphaltene, solubility, reservoir simulation

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Authors: Ali N. Suri, Ahmad A. Al-Makhlufi

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In this paper the problem of buckling of plates on foundation of finite length and with different side support is studied. The Finite Strip Method is used as tool for the analysis. This method uses finite strip elastic, foundation, and geometric matrices to build the assembly matrices for the whole structure, then after introducing boundary conditions at supports, the resulting reduced matrices is transformed into a standard Eigenvalue-Eigenvector problem. The solution of this problem will enable the determination of the buckling load, the associated buckling modes and the buckling wave length. To carry out the buckling analysis starting from the elastic, foundation, and geometric stiffness matrices for each strip a computer program FORTRAN list is developed. Since stiffness matrices are function of wave length of buckling, the computer program used an iteration procedure to find the critical buckling stress for each value of foundation modulus and for each boundary condition. The results showed the use of elastic medium to support plates subject to axial load increase a great deal the buckling load, the results found are very close with those obtained by other analytical methods and experimental work. The results also showed that foundation compensates the effect of the weakness of some types of constraint of side support and maximum benefit found for plate with one side simply supported the other free.

Keywords: buckling, finite strip, different sides support, plates on foundation

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Authors: Parul Sahu

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In recent years, seawater desalination has been emerged as a potential resource to circumvent water scarcity, especially in coastal regions. Among the various methods, thermal evaporation or distillation and membrane operations like Reverse Osmosis (RO) has been exploited at commercial scale. However, the energy cost and maintenance expenses associated with these processes remain high. In this context Freeze Desalination (FD), subjected to the availability of low cost refrigeration, offers an exciting alternative. Liquefied Natural Gas (LNG) regasification terminals provide an opportunity to utilize the refrigeration available with regasification of LNG. This work presents the conceptualization and development of a process scheme integrating the ice and hydrate based FD to the LNG regasification process. This integration overcomes the high energy demand associated with FD processes by utilizing the refrigeration associated with LNG regasification. An optimal process scheme was obtained by performing process simulation using ASPEN PLUS simulator. The results indicated the new proposed process requires only 1 kWh/m³ of energy with the utilization of maximum refrigeration. In addition, a sensitivity analysis was also performed to study the effect of various process parameters on water recovery and energy consumption for the proposed process. The results show that the energy consumption decreases by 30% with an increase in water recovery from 30% to 60%. However, due to operational limitations associated with ice and hydrate handling in seawater, the water recovery cannot be maximized but optimized. The proposed process can be potentially used to desalinate seawater in integration with LNG regasification terminal.

Keywords: freeze desalination, liquefied natural gas regasification, process simulation, refrigeration

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Authors: Ahmed Hammad, Yehia Abdel-Nasser, Mohamed Shamma

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The main configuration of ship construction consists of standard and fabricated stiffening members which are commonly used in shipbuilding such as fabricated T-sections. During the welding process, the non-uniform heating and rapid cooling lead to the inevitable presence of out-of-plane distortion and welding induced residual stresses. Because of these imperfections, the fabricated structural members may not attain their design load to be carried. The removal of these imperfections will require extra man-hours. In the present work, controlling these imperfections has been investigated at both design and fabrication stages. A typical fabricated T-girder is selected to investigate the problem of these imperfections using double-side welding. A numerical simulation based on finite element (FE) modeling has been used to investigate the effect of different parameters of the selected fabricated T-girder such as geometrical properties and welding sequences on the magnitude of welding imperfections. FE results were compared with the results of experimental model of a double-side fillet weld. The present work concludes that: Firstly, in the design stage, the optimum geometry of the fabricated T- girder is determined based on minimum steel weight and out- of- plane distortion. Secondly, in the fabrication stage, the best welding sequence is determined on the basis of minimum welding out- of- plane distortion.

Keywords: fabricated T-girder, FEM, out-of-plane distortion, section modulus, welding residual stresses

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Authors: Tzu-Wen Liu, Yi-Feng Lin, Yu-Shao Chen

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CO_2 is believed to be partly responsible for changes to the global climates. Carbon capture and storage (CCS) is one way to reduce carbon dioxide emissions in the past. Recently, how to convert the captured CO_2 into fine chemicals gets lots of attention owing to reducing carbon dioxide emissions and providing greener feedstock for the chemicals industry. A variety of products can be manufactured from carbon dioxide and the most attractive products are cyclic carbonates. Therefore, the kind of catalyst plays an important role in cycloaddition of carbon dioxide to epoxides. Magnesium oxide can be an efficiency heterogeneous catalyst for the cycloaddition of carbon dioxide to epoxides because magnesium oxide has both acid and base active sites and can provide the adsorption of carbon dioxide, promoting ring-opening reaction. Spinning disk reactor (SDR) is one of the device of high-gravity technique and has successfully used for synthesis of nanoparticles by precipitation methods because of the high mass transfer rate. Synthesis of nanoparticles in SDR has advantages of low energy consumption and easy to scale up. The aim of this research is to synthesize magnesium hydroxide nanoparticles in SDR as precursors for magnesium oxide. Experimental results showed that the calcination temperature of magnesium hydroxide to magnesium oxide, and the pressure and temperature of cycloaddition reaction had significantly effect on the conversion and selectivity of the reaction.

Keywords: magnesium oxide, catalyst, cycloaddition, spinning disk reactor, carbon dioxide

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Authors: Andreia Cucuruz, Cristina Daniela Ghitulica, Georgeta Voicu, Cristina Busuioc

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Ceramics based on calcium phosphates have lately increased attention for tissue engineering because they can be used as substitute bones or for bone regeneration since they mimic very well the nanostructure of tough bone tissue, but also because of other advantages such as a very good biocompatibility and osseointegration. This study aims the preparation and characterization of ceramic materials on the basis of TCP (Ca₃(PO₄)₂), within which calcium ions are substituted by magnesium ions (Mg²⁺) in order to improve the regenerative properties of these materials. TCP-Mg material was synthesized by chemical precipitation method using calcium oxide (CaO) and phosphoric acid (H₃PO₄) as precursors. The objective was to obtain powders with different concentrations of Mg in order to analyze the effect of magnesium ions on the physicochemical properties of phosphate ceramics and in vitro degradation in simulated biological fluid (SBF). Ceramic powders were characterized in vitro but also from the compositional and microstructural point of view. TCP_Mg powders were prepared through wet chemical method from calcium oxide (CaO), magnesium oxide nanopowder (MgO < 50 nm particle size (BET) Sigma Aldrich), phosphoric acid (H₃PO₄ - 85 wt.% in H₂O, 99.99% trace metals basis - Sigma Aldrich). In order to determine the quantities of raw materials, calculations were performed to obtain HAp with Ca/P ratio of 1.5.

Keywords: bone regeneration, magnesium substitution, tricalcium phosphate, tissue engineering

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Authors: Jakub Bartus, Jaroslav Odrobinak

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In general, composite steel and concrete structures present an effective structural solution utilizing the full potential of both materials. As they have numerous advantages on the construction side, they can greatly reduce the overall cost of construction, which has been the main objective of the last decade, highlighted by the current economic and social crisis. The study represents not only an analysis of composite beams’ behavior having web openings but emphasizes the influence of these openings on the total strain distribution at the level of the steel bottom flange as well. The major investigation was focused on a change in structural performance with respect to various layouts of openings. Examining this structural modification, an improvement of load carrying capacity of composite beams was a prime objective. The study is divided into analytical and numerical parts. The analytical part served as an initial step into the design process of composite beam samples, in which optimal dimensions and specific levels of utilization in individual stress states were taken into account. The numerical part covered the discretization of the preset structural issue in the form of a finite element (FE) model using beam and shell elements accounting for material non–linearities. As an outcome, several conclusions were drawn describing and explaining the effect of web opening presence on the structural performance of composite beams.

Keywords: beam, steel flange, total strain, web opening

Procedia PDF Downloads 60

Authors: Seung-Hwa Baek, In-Jung Nam, Sang-Han Lee

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The development of anti-melanogenic agents is important for the prevention of serious esthetic problem like a melasma, freckle, age spots, and chloasma. The aim of this study was to investigate the anti-melanogenic effect of sesamol, an active lignan isolated from sesame seed, by mushroom and cellular tyrosinase assay, melanin content and the analysis of melanogensis-related mRNA expressions in melana cells. Sesamol showed strong inhibitory activity against the mushroom tyrosinase in a dose-dependent manner. Intracellular tyrosinase inhibition activity was also confirmed by zymography. At a concentration of 50 μM, sesamol inhibited melanin production in melan-a cells with no cytoxicity while those of phenylthiourea (PTU) as a positive control were the same condition. Sesamol significantly inhibited the expression of melanogensis-related genes, such as tyrosinase, tyrosinase-related protein-1 (TRP-1), dopachrome tautomerase (Dct), microphthalmia-associated transcription factor (MITF) and melanocortin 1 receptor (MC1R). These findings indicate that sesamol could reduce melanin biosynthesis via the downregulation of tyrosinase activity and melanin production via subsequent gene expression of melanogenesis-related proteins. Together, these results suggest that the sesamol have strong potential in inhibiting melanin biosynthesis, in that the substance may be used as a new skin-whitening agent of cosmetic materials.

Keywords: sesamol, sesame seed, melanin biosynthesis, melanogenesis-related gene, skin-whitening agent

Procedia PDF Downloads 375