Search results for: secondary circulation
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 3511

Search results for: secondary circulation

2371 A Hydrometallurgical Route for the Recovery of Molybdenum from Mo-Co Spent Catalyst

Authors: Bina Gupta, Rashmi Singh, Harshit Mahandra

Abstract:

Molybdenum is a strategic metal and finds applications in petroleum refining, thermocouples, X-ray tubes and in making of steel alloy owing to its high melting temperature and tensile strength. The growing significance and economic value of molybdenum have increased interest in the development of efficient processes aiming its recovery from secondary sources. Main secondary sources of Mo are molybdenum catalysts which are used for hydrodesulphurisation process in petrochemical refineries. The activity of these catalysts gradually decreases with time during the desulphurisation process as the catalysts get contaminated with toxic material and are dumped as waste which leads to environmental issues. In this scenario, recovery of molybdenum from spent catalyst is significant from both economic and environmental point of view. Recently ionic liquids have gained prominence due to their low vapour pressure, high thermal stability, good extraction efficiency and recycling capacity. Present study reports recovery of molybdenum from Mo-Co spent leach liquor using Cyphos IL 102[trihexyl(tetradecyl)phosphonium bromide] as an extractant. Spent catalyst was leached with 3 mol/L HCl and the leach liquor containing Mo-870 ppm, Co-341 ppm, Al-508 ppm and Fe-42 ppm was subjected to extraction step. The effect of extractant concentration on the leach liquor was investigated and almost 85% extraction of Mo was achieved with 0.05 mol/L Cyphos IL 102. Results of stripping studies revealed that 2 mol/L HNO3 can effectively strip 94% of the extracted Mo from the loaded organic phase. McCabe-Thiele diagrams were constructed to determine the number of stages required for quantitative extraction and stripping of molybdenum and were confirmed by counter current simulation studies. According to McCabe-Thiele extraction and stripping isotherms, two stages are required for quantitative extraction and stripping of molybdenum at A/O= 1:1. Around 95.4% extraction of molybdenum was achieved in two stage counter current at A/O= 1:1 with negligible extraction of Co and Al. However, iron was coextracted and removed from the loaded organic phase by scrubbing with 0.01 mol/L HCl. Quantitative stripping (~99.5 %) of molybdenum was achieved with 2.0 mol/L HNO3 in two stages at O/A=1:1. Overall ~95.0% molybdenum with 99 % purity was recovered from Mo-Co spent catalyst. From the strip solution, MoO3 was obtained by crystallization followed by thermal decomposition. The product obtained after thermal decomposition was characterized by XRD, FE-SEM and EDX techniques. XRD peaks of MoO3correspond to molybdite Syn-MoO3 structure. FE-SEM depicts the rod like morphology of synthesized MoO3. EDX analysis of MoO3 shows 1:3 atomic percentage of molybdenum and oxygen. The synthesised MoO3 can find application in gas sensors, electrodes of batteries, display devices, smart windows, lubricants and as catalyst.

Keywords: cyphos IL 102, extraction, Mo-Co spent catalyst, recovery

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2370 Alteration of Placental Development and Vascular Dysfunction in Gestational Diabetes Mellitus Has Impact on Maternal and Infant Health

Authors: Sadia Munir

Abstract:

The aim of this study is to investigate changes in placental development and vascular dysfunction which subsequently affect feto-maternal health in pregnancies complicated by gestational diabetes mellitus (GDM). Fetal and postnatal adverse health outcomes of GDM are shown to be associated with disturbances in placental structure and function. Children of women with GDM are more likely to be obese and diabetic in childhood and adulthood. GDM also increases the risk of adverse pregnancy outcomes, including preeclampsia, birth injuries, macrosomia and neonatal hypoglycemia, respiratory distress syndrome, neonatal cardiac dysfunction and stillbirth. Incidences of type 2 diabetes in the MENA region are growing at an alarming rate which is estimated to become more than double by 2030. Five of the top 10 countries for diabetes prevalence in 2010 were in the Gulf region. GDM also increases the risk of development of type 2 diabetes. Interestingly, more than half of the women with GDM develop diabetes later in their life. The human placenta is a temporary organ located at the interface between mother and fetal blood circulation. Placenta has a central role as both a producer as well as a target of several molecules that are involved in placental development and function. We have investigated performed a Pubmed search with key words placenta, GDM, placental villi, vascularization, cytokines, growth factors, inflammation, hypoxia, oxidative stress and pathophysiology. We have investigated differences in the development and vascularization of placenta, their underlying causes and impact on feto-maternal health through literature review. We have also identified gaps in the literature and research questions that need to be answered to completely understand the central role of placenta in the GDM. This study is important in understanding the pathophysiology of placenta due to changes in the vascularization of villi, surface area and diameter of villous capillaries in pregnancies complicated by GDM. It is necessary to understand these mechanisms in order to develop treatments to reverse their effects on placental malfunctioning, which in turn, will result in improved mother and child health.

Keywords: gestational diabetes mellitus, placenta, vasculature, villi

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2369 White-Rot Fungi Phellinus as a Source of Antioxidant and Antitumor Agents

Authors: Yogesh Dalvi, Ruby Varghese, Nibu Varghese, C. K. Krishnan Nair

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Introduction: The Genus Phellinus, locally known as Phansomba is a well-known traditional folk medicine. Especially, in Western Ghats of India, many tribes use several species of Phellinus for various ailments related to teeth, throat, tongue, stomach and even wound healing. It is one of the few mushrooms which play a pivotal role in Ayurvedic Dravyaguna. Aim: The present study focuses on to investigate phytochemical analysis, antioxidant, and antitumor (in vitro and in vivo) potential of Phellinus robinae from South India, Kerala Material and Methods: The present study explores the following: 1. Phellinus samples were collected from Ranni, Pathanamthitta district of Kerala state, India from Artocarpus heterophyllus Lam. and species were identified using rDNA region. 2. The fruiting body was shadow dried, powdered and extracted with 50% alcohol using water bath at 60°C which was further condensed by rotary evaporator and lyophilized at minus 40°C temperature. 3. Secondary metabolites were analyzed by using various phytochemical screening assay (Hager’s Test, Wagner’s Test, Sodium hydroxide Test, Lead acetate Test, Ferric chloride Test, Folin-ciocalteu Test, Foaming Test, Benedict’s test, Fehling’s Test and Lowry’s Test). 4. Antioxidant and free radical scavenging activity were analyzed by DPPH, FRAP and Iron chelating assay. 5. The antitumor potential of Water alcohol extract of Phellinus (PAWE) is evaluated through In vitro condition by Trypan blue dye exclusion method in DLA cell line and In vivo by murine model. Result and Discussion: Preliminary phytochemical screening by various biochemical tests revealed presence of a variety of active secondary molecules like alkaloids, flavanoids, saponins, carbohydrate, protein and phenol. In DPPH and FRAP assay PAWE showed significantly higher antioxidant activity as compared to standard Ascorbic acid. While, in Iron chelating assay, PAWE exhibits similar antioxidant activity that of Butylated Hydroxytoluene (BHT) as standard. Further, in the in vitro study, PAWE showed significant inhibition on DLA cell proliferation in dose dependent manner and showed no toxicity on mice splenocytes, when compared to standard chemotherapy drug doxorubicin. In vivo study, oral administration of PAWE showed dose dependent tumor regression in mice and also raised the immunogenicity by restoring levels of antioxidant enzymes in liver and kidney tissue. In both in vitro and in vivo gene expression studies PAWE up-regulates pro-apoptotic genes (Bax, Caspases 3, 8 and 9) and down- regulates anti-apoptotic genes (Bcl2). PAWE also down regulates inflammatory gene (Cox-2) and angiogenic gene (VEGF). Conclusion: Preliminary phytochemical screening revealed that PAWE contains various secondary metabolites which contribute to its antioxidant and free radical scavenging property as evaluated by DPPH, FRAP and Iron chelating assay. PAWE exhibits anti-proliferative activity by the induction of apoptosis through a signaling cascade of death receptor-mediated extrinsic (Caspase8 and Tnf-α), as well as mitochondria-mediated intrinsic (caspase9) and caspase pathways (Caspase3, 8 and 9) and also by regressing angiogenic factor (VEGF) without any inflammation or adverse side effects. Hence, PAWE serve as a potential antioxidant and antitumor agent.

Keywords: antioxidant, antitumor, Dalton lymphoma ascites (DLA), fungi, Phellinus robinae

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2368 The Efficiency of the Use of Medical Bilingual Dictionary in English Language Teaching in Vocational College

Authors: Zorana Jurinjak, Christos Alexopoulos

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The aim of this paper is to examine the effectiveness of using a medical bilingual dictionary in teaching English in a vocational college. More precisely, to what extent the use of bilingual medical dictionary in relation to the use of Standard English bilingual dictionaries influences the results on tests, and thus the acquisition of better competence of students mastering the subject terminology. Secondary interest in this paper would be to raise awareness among students and teachers about the advantages of dictionary use. The experiment was conducted at College of Applied Health Sciences in Ćuprija on a sample of 90 students. The respondents translated three medical texts with 42 target terms. Statistical analyses of the data obtained show that the differences in average time and correct answers favor the students who used medical dictionary.

Keywords: bilingual medical dictionary, standard english bilingual dictionary, medical terminology, EOS, ESP

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2367 Mathematics Teachers’ Background Characteristics as a Correlate of Secondary School Students’ Achievement in Mathematics in Gombe State, Nigeria

Authors: Ali Adamu

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Teachers’ background characteristics as a correlate of students’ achievement in Mathematics were studied in Gombe State. Pearson Product Moment Correlation Coefficient was used for the analysis. Five Hundred and Twelve (512) students and 20 teachers from 12 schools in Gombe State of Nigeria were used for the study. Students’ Achievement Tests and Mathematics Teachers’ backgrounds were instruments for the study. The findings indicated that teachers’ qualifications, experience of the teacher, and teachers’ personalities had a positive correlation with students’ achievement. Recommendations are made, which include allowing the teachers to go for training as well as the government should ensure recruiting teachers that have experience in the teaching job.

Keywords: achievement-test, teachers’ personality, teaching mathematics, teacher-background

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2366 Constructing a Two-Tier Test about Source Current to Diagnose Pre-Service Elementary School Teacher’ Misconceptions

Authors: Abdeljalil Metioui

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The purpose of this article is to present the results of two-stage qualitative research. The first involved the identification of the alternative conceptions of 80 elementary pre-service teachers from Quebec in Canada about the operation of simple electrical circuits. To do this, they completed a two-choice questionnaire (true or false) with justification. Data analysis identifies many conceptual difficulties. For example, for their majority, whatever the electrical device that composes an electrical circuit, the current source (power supply), and the generated electrical power is constant. The second step was to develop a double multiple-choice questionnaire based on the identified designs. It allows teachers to quickly diagnose their students' conceptions and take them into account in their teaching.

Keywords: development, electrical circuits, two-tier diagnostic test, secondary and high school

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2365 Thermoelectric Cooler As A Heat Transfer Device For Thermal Conductivity Test

Authors: Abdul Murad Zainal Abidin, Azahar Mohd, Nor Idayu Arifin, Siti Nor Azila Khalid, Mohd Julzaha Zahari Mohamad Yusof

Abstract:

A thermoelectric cooler (TEC) is an electronic component that uses ‘peltier’ effect to create a temperature difference by transferring heat between two electrical junctions of two different types of materials. TEC can also be used for heating by reversing the electric current flow and even power generation. A heat flow meter (HFM) is an equipment for measuring thermal conductivity of building materials. During the test, water is used as heat transfer medium to cool the HFM. The existing re-circulating cooler in the market is very costly, and the alternative is to use piped tap water to extract heat from HFM. However, the tap water temperature is insufficiently low to enable heat transfer to take place. The operating temperature for isothermal plates in the HFM is 40°C with the range of ±0.02°C. When the temperature exceeds the operating range, the HFM stops working, and the test cannot be conducted. The aim of the research is to develop a low-cost but energy-efficient TEC prototype that enables heat transfer without compromising the function of the HFM. The objectives of the research are a) to identify potential of TEC as a cooling device by evaluating its cooling rate and b) to determine the amount of water savings using TEC compared to normal tap water. Four (4) peltier sets were used, with two (2) sets used as pre-cooler. The cooling water is re-circulated from the reservoir into HFM using a water pump. The thermal conductivity readings, the water flow rate, and the power consumption were measured while the HFM was operating. The measured data has shown decrease in average cooling temperature difference (ΔTave) of 2.42°C and average cooling rate of 0.031°C/min. The water savings accrued from using the TEC is projected to be 8,332.8 litres/year with the application of water re-circulation. The results suggest the prototype has achieved required objectives. Further research will include comparing the cooling rate of TEC prototype against conventional tap water and to optimize its design and performance in terms of size and portability. The possible application of the prototype could also be expanded to portable storage for medicine and beverages.

Keywords: energy efficiency, thermoelectric cooling, pre-cooling device, heat flow meter, sustainable technology, thermal conductivity

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2364 Effects of Temperature and the Use of Bacteriocins on Cross-Contamination from Animal Source Food Processing: A Mathematical Model

Authors: Benjamin Castillo, Luis Pastenes, Fernando Cerdova

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The contamination of food by microbial agents is a common problem in the industry, especially regarding the elaboration of animal source products. Incorrect manipulation of the machinery or on the raw materials can cause a decrease in production or an epidemiological outbreak due to intoxication. In order to improve food product quality, different methods have been used to reduce or, at least, to slow down the growth of the pathogens, especially deteriorated, infectious or toxigenic bacteria. These methods are usually carried out under low temperatures and short processing time (abiotic agents), along with the application of antibacterial substances, such as bacteriocins (biotic agents). This, in a controlled and efficient way that fulfills the purpose of bacterial control without damaging the final product. Therefore, the objective of the present study is to design a secondary mathematical model that allows the prediction of both the biotic and abiotic factor impact associated with animal source food processing. In order to accomplish this objective, the authors propose a three-dimensional differential equation model, whose components are: bacterial growth, release, production and artificial incorporation of bacteriocins and changes in pH levels of the medium. These three dimensions are constantly being influenced by the temperature of the medium. Secondly, this model adapts to an idealized situation of cross-contamination animal source food processing, with the study agents being both the animal product and the contact surface. Thirdly, the stochastic simulations and the parametric sensibility analysis are compared with referential data. The main results obtained from the analysis and simulations of the mathematical model were to discover that, although bacterial growth can be stopped in lower temperatures, even lower ones are needed to eradicate it. However, this can be not only expensive, but counterproductive as well in terms of the quality of the raw materials and, on the other hand, higher temperatures accelerate bacterial growth. In other aspects, the use and efficiency of bacteriocins are an effective alternative in the short and medium terms. Moreover, an indicator of bacterial growth is a low-level pH, since lots of deteriorating bacteria are lactic acids. Lastly, the processing times are a secondary agent of concern when the rest of the aforementioned agents are under control. Our main conclusion is that when acclimating a mathematical model within the context of the industrial process, it can generate new tools that predict bacterial contamination, the impact of bacterial inhibition, and processing method times. In addition, the mathematical modeling proposed logistic input of broad application, which can be replicated on non-meat food products, other pathogens or even on contamination by crossed contact of allergen foods.

Keywords: bacteriocins, cross-contamination, mathematical model, temperature

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2363 One Plus One is More than Two: Why Nurse Recruiters Need to Use Various Multivariate Techniques to Understand the Limitations of the Concept of Emotional Intelligence

Authors: Austyn Snowden

Abstract:

Aim: To examine the construct validity of the Trait Emotional Intelligence Questionnaire Short form. Background: Emotional intelligence involves the identification and regulation of our own emotions and the emotions of others. It is therefore a potentially useful construct in the investigation of recruitment and retention in nursing and many questionnaires have been constructed to measure it. Design: Secondary analysis of existing dataset of responses to TEIQue-SF using concurrent application of Rasch analysis and confirmatory factor analysis. Method: First year undergraduate nursing and computing students completed Trait Emotional Intelligence Questionnaire-Short Form. Responses were analysed by synthesising results of Rasch analysis and confirmatory factor analysis.

Keywords: emotional intelligence, rasch analysis, factor analysis, nurse recruiters

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2362 Impact of Youth Corners and Knowledge about Human Sexuality among Young Adults and Adolescents of Nigerian Population in the Prevention of Sexually Transmitted Diseases

Authors: Gabriel I. Oke, Faremi O. Ayodeji

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Background: Access to youth Friendly Health Corners is vital for ensuring sexual reproductive health and total well being of young Adults since human sexuality has been widely misunderstood. Meanwhile, behavior of young people towards it remains at variance with the alarm. This study attempt to access the impact of youth corners also called Adolescent Friendly Health Corners on manifestation of human sexual behavior among Nigerian adolescent and young adults. Description: Hundred young adults and adolescents of both sex between the Age range of 12-25years were randomly selected from 5 secondary schools and 3 prominent universities in Southwestern Nigeria and focal group discussions (FGD) were conducted among them. Fifty secondary and primary health facilities were visited between February and June 2017 to conduct interviews for health workers and to ascertain the presence or absence of youth corners. Results: 95% of the health facilities visited lack Youth Corners section neither are they willing to make provision for it due to lack of workmanship and sponsorship. However, 5% with Youth corners does not have well-trained Counselors or a Health Educator but health professionals from nursing profession. 90% of the respondents of which 16-17 years of Age is the mean age had their first sexual exposure with no use of protection even before been introduced to what Sexuality is all about. Virtually, none of the respondents had ever visited a Youth Corner before or heard the term before. 86% have heard about the term STI before of which 60% are using protection, 10% care less about any information attached to the term STI, 4% have not heard of the term STI before even when translated to their local dialect. 20% are abstaining as at the time the study was conducted and they attribute their sexual decision to religion and parental influence. Of the age group 20-25, 45% claimed they have had symptoms of one STI or the other and 40% claimed they have been tested positive for an STI before of which 12% have positive HIV status. Promiscuous behaviors were found among them before they reach the age 16years with pornography ranking the highest, followed by masturbation. Respondents blame this on peer pressure, the lack of Youth Friendly Centers in their locality and lack of proper Sexual Orientation on time. About half of the respondents make use of contraceptives while others have varying views. We found out that inability to access Youth Friendly Centers amongst the respondents might be one of the singular reasons of their early experimentation of their sex life and lack of healthy sexual lifestyle. (95% CI, P=0.922) Conclusion: The study reveals that a connection between youth Friendly Centers and Prevention of Sexually Transmitted Diseases, therefore more sustainable Friendly Youth Corners with well-trained educators are needed in various Health facilities to checkmate the numerous risks of Young People along the path of adulthood.

Keywords: adolescents, sexually transmitted infections, reproductive health, youth corners

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2361 Analysis of Adolescents Birth Rate in Zimbabwe: The Case of High Widening Gap between Rural and Urban Areas, Secondary Analysis from the 2022 National Population and Housing Census

Authors: Mercy Marimirofa, Farai Machinga, Alfred Zvoushe, Tsitsidzaishe Musvosvi

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Adolescent Birth rate (ABR) is an important indicator of both gender equality and equity in the country. This is the number of births to women aged between 15 and 19 years per 1000 live births. There has been a decreasing trend in ABR in Zimbabwe since 2014. However, the difference between rural areas and urban areas has continued to widen. A secondary analysis was conducted to assess the differences in ABR between the rural areas of Zimbabwe and the urban areas. This was also done to determine the root causes of high ABR in rural areas compared to urban areas and the impact this may cause to the economic development of the nation. The analysis was done according to geographical characteristics (provinces). A total of 69,335 females aged 10 to 19 years had live births among a total population of 791,914 females aged 15 to 19 years. The total Adolescent Birth rate in Zimbabwe is 87/1000 live births, while in rural areas, it is 114.4/1000 live births compared to urban areas, which is 49.7/1000 live births. A decrease in the ABR trends has been recorded since 2014 from 143/1000 live births among adolescents in rural areas to 97/1000 live births in urban areas. This shows that rural areas still have high rates of ABR compared to their urban counterparts, and the gap is still wide. High ABR is a result of early child marriages, teenage pregnancies as well as poverty. Most of these marriages (46%) are intergenerational relationships and have resulted in an increase in gender-based violence cases among adolescents, poor health outcomes, including pregnancy complications such as eclampsia, Cephalous Pelvic Disproportion (CPD), and obstructed labour. Maternal deaths among adolescence is also high compared to adults. Furthermore, the increase of school dropouts among adolescent girls is on the rise due to teen pregnancies. These challenges are being faced mostly by rural adolescent girls as compared to their urban counterparts. The widening gap in ABR between urban areas and rural areas is a matter of concern and needs to be addressed. There is a need to inform policy, programming, and interventions targeting rural areas to address the challenges and gaps in reducing ABR. This abstract is to inform policymakers on the strategies and resources required to address the challenges currently distressing adolescents. There is a need to improve access to Sexual and Reproductive Health (SRH) Services by adolescents and reduce the age of consent to access SRH services should be reduced from 18 years for ease access to young people to reduce teenage pregnancies. Comprehensive sexuality education, both in-school and out of school, should be strengthened to increase knowledge among young people on sexuality.

Keywords: adolescence birth rate, live birth, teenage pregnancies, SRH services

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2360 Value Adding of Waste Biomass of Capsicum and Chilli Crops for Medical and Health Supplement Industries

Authors: Mursleen Yasin, Sunil Panchal, Michelle Mak, Zhonghua Chen

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“The use of agricultural and horticultural waste to obtain beneficial products. Thus reduce its environmental impact and help the general population.” Every year 20 billion dollars of food is wasted in the world. All the energy, resources, nutrients and metabolites are lost to the landfills as well. On farm production losses are a main issue in agriculture. Almost 25% vegetables never leave the farm because they are not considered perfect for supermarkets and treated as waste material along with the rest of the plant parts. For capsicums, this waste is 56% of the total crop. Capsicum genus is enriched with a group of compounds called capsaicinoids which are a source of spiciness of these fruits. Capsaicin and dihydrocapsaicin are the major members comprising almost 90% of this group. The major production and accumulation site is the non-edible part of fruit i.e., placenta. Other parts of the plant, like stem, leaves, pericarp and seeds, also contain these pungent compounds. Capsaicinoids are enriched with properties like analgesic, antioxidants, anti-inflammatory, antibacterial, anti-virulence anti-carcinogenic, chemo preventive, chemotherapeutic, antidiabetic etc. They are also effective in treating problems related to gastrointestinal tract, lowering cholesterol and triglycerides in obesity. The aim of the study is to develop a standardised technique for capsaicinoids extraction and to identify better nutrient treatment for fruit and capsaicinoids yield. For research 3 capsicum and 2 chilli varieties were grown in a high-tech glass house facility in Sydney, Australia. Plants were treated with three levels of nutrient treatments i.e., EC 1.8, EC 2.8 and EC 3.8 in order to check its effect on fruit yield and capsaicinoids concentration. Solvent extraction procedure is used with 75% ethanol to extract these secondary metabolites. Physiological, post-harvest and waste biomass measurement and metabolomic analysis are also performed. The results showed that EC 2.8 gave the better fruit yield of capsicums, and those fruits have the higher capsaicinoids concentration. For chillies, higher EC levels had better results than lower treatment. The UHPLC analysis is done to quantify the compounds, and a decrease in capsaicin concentration is observed with the crop maturation. The outcome of this project is a sustainable technique for extraction of capsaicinoids which can easily be adopted by farmers. In this way, farmers can help in value adding of waste by extracting and selling capsaicinoids to nutraceutical and pharmaceutical industries and also earn some secondary income from the 56% waste of capsicum crop.

Keywords: capsaicinoids, plant waste, capsicum, solvent extraction, waste biomass

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2359 Algorithm and Software Based on Multilayer Perceptron Neural Networks for Estimating Channel Use in the Spectral Decision Stage in Cognitive Radio Networks

Authors: Danilo López, Johana Hernández, Edwin Rivas

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The use of the Multilayer Perceptron Neural Networks (MLPNN) technique is presented to estimate the future state of use of a licensed channel by primary users (PUs); this will be useful at the spectral decision stage in cognitive radio networks (CRN) to determine approximately in which time instants of future may secondary users (SUs) opportunistically use the spectral bandwidth to send data through the primary wireless network. To validate the results, sequences of occupancy data of channel were generated by simulation. The results show that the prediction percentage is greater than 60% in some of the tests carried out.

Keywords: cognitive radio, neural network, prediction, primary user

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2358 The Value of Computerized Corpora in EFL Textbook Design: The Case of Modal Verbs

Authors: Lexi Li

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This study aims to contribute to the field of how computer technology can be exploited to enhance EFL textbook design. Specifically, the study demonstrates how computerized native and learner corpora can be used to enhance modal verb treatment in EFL textbooks. The linguistic focus is will, would, can, could, may, might, shall, should, must. The native corpus is the spoken component of BNC2014 (hereafter BNCS2014). The spoken part is chosen because the pedagogical purpose of the textbooks is communication-oriented. Using the standard query option of CQPweb, 5% of each of the nine modals was sampled from BNCS2014. The learner corpus is the POS-tagged Ten-thousand English Compositions of Chinese Learners (TECCL). All the essays under the “secondary school” section were selected. A series of five secondary coursebooks comprise the textbook corpus. All the data in both the learner and the textbook corpora are retrieved through the concordance functions of WordSmith Tools (version, 5.0). Data analysis was divided into two parts. The first part compared the patterns of modal verbs in the textbook corpus and BNC2014 with respect to distributional features, semantic functions, and co-occurring constructions to examine whether the textbooks reflect the authentic use of English. Secondly, the learner corpus was compared with the textbook corpus in terms of the use (distributional features, semantic functions, and co-occurring constructions) in order to examine the degree of influence of the textbook on learners’ use of modal verbs. Moreover, the learner corpus was analyzed for the misuse (syntactic errors, e.g., she can sings*.) of the nine modal verbs to uncover potential difficulties that confront learners. The results indicate discrepancies between the textbook presentation of modal verbs and authentic modal use in natural discourse in terms of distributions of frequencies, semantic functions, and co-occurring structures. Furthermore, there are consistent patterns of use between the learner corpus and the textbook corpus with respect to the three above-mentioned aspects, except could, will and must, partially confirming the correlation between the frequency effects and L2 grammar acquisition. Further analysis reveals that the exceptions are caused by both positive and negative L1 transfer, indicating that the frequency effects can be intercepted by L1 interference. Besides, error analysis revealed that could, would, should and must are the most difficult for Chinese learners due to both inter-linguistic and intra-linguistic interference. The discrepancies between the textbook corpus and the native corpus point to a need to adjust the presentation of modal verbs in the textbooks in terms of frequencies, different meanings, and verb-phrase structures. Along with the adjustment of modal verb treatment based on authentic use, it is important for textbook writers to take into consideration the L1 interference as well as learners’ difficulties in their use of modal verbs. The present study is a methodological showcase of the combination both native and learner corpora in the enhancement of EFL textbook language authenticity and appropriateness for learners.

Keywords: EFL textbooks, learner corpus, modal verbs, native corpus

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2357 Numerical and Experimental Investigation of Impeller Trimming on Fluid Flow inside a Centrifugal Pump

Authors: Rouhollah Torabi, Ashkan Chavoshi, Sheyda Almasi, Shima Almasi

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In this paper the effect of impeller trim on centrifugal pump performance is studied and the most important effect which is decreasing the flow rate, differential head and efficiency is analyzed. For this case a low specific speed centrifugal pump is simulated with CFD. Total flow inside the pump including the secondary flow in sidewall gap which form internal leakage is modeled simultaneously in CFX software. The flow field in different area of pumps such as inside impeller, volute, balance holes and leakage through wear rings are studied. To validate the results experimental tests are done for various impeller diameters. Results also compared with analytic equations which predict pump performance with trimmed impeller.

Keywords: centrifugal pump, CFD, impeller, trim

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2356 Combined Localization, Beamforming, and Interference Threshold Estimation in Underlay Cognitive System

Authors: Omar Nasr, Yasser Naguib, Mohamed Hafez

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This paper aims at providing an innovative solution for blind interference threshold estimation in an underlay cognitive network to be used in adaptive beamforming by secondary user Transmitter and Receiver. For the task of threshold estimation, blind detection of modulation and SNR are used. For the sake of beamforming several localization algorithms are compared to settle on best one for cognitive environment. Beamforming algorithms as LCMV (Linear Constraint Minimum Variance) and MVDR (Minimum Variance Distortion less) are also proposed and compared. The idea of just nulling the primary user after knowledge of its location is discussed against the idea of working under interference threshold.

Keywords: cognitive radio, underlay, beamforming, MUSIC, MVDR, LCMV, threshold estimation

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2355 Cross Carpeting in Nigerian Politics: Some Legal and Moral Issues Generated

Authors: Agbana Olaseinde Julius, Opadere Olaolu Stephen

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The concept of cross carpeting is as old as politics itself. Basically, it entails an individual leaving a political party/group, to join another. The reasons for which cross carpeting is embarked upon are diverse: ideological differences; ethnic and/or religious differences; access to actual or perceived better political opportunities; liberty of association; rancor; etc. The current democratic dispensation in Nigeria has experienced renewed and rather alarming rate of cross carpeting, for reasons including those enumerated above and others. Right to cross carpet is inherent in a democratic setting as well as the political stakeholder; so does it also comprise of the constitutional right of ‘freedom of association’. However, the current species of cross carpeting in Nigeria requires scrutiny, in view of some potential legal and moral challenges it poses for both the present and the future. Cross carpeting is considered both legal and constitutional, but the current spate raises the question of expediency, particularly in a nascent democracy. It is considered to have a propensity of negatively impacting political stability in a polity with fragile nerves. Importantly too, cross carpeting is considered a potential damage to the psyche of posterity with regards to a warped disposition to promises, honour and integrity. The perceived peculiar dimension of cross carpeting in Nigeria raises questions on the quality of leadership presently obtainable in the country, vis-à-vis greed, self-centeredness, disregard for the concern and interest of avowed followers/fans, entrenchment of distrust, etc. Thus, the study made use of primary and secondary sources of information. The primary sources included the Constitutions of the Federal Republic of Nigeria 1999 (as amended); judicial decisions; and the Electoral Act, 2010 (as Amended). The secondary sources comprised of information from books, journals, newspapers, magazines and Internet documents. Data obtained from these sources were subjected to content analysis. Findings of this study show that though the act of cross carpeting may not be in breach of any Statute or Law, it however, in most cases, breaches the morals of expediency. The morality thereof is far from justifiable, and should be condemned in the interest of the present and posterity. There is a great and urgent need to embark on a re-entrenchment of the culture of political ideology in the Nigerian polity, as obtainable in developed democracies. In conclusion, the need to exercise the right of cross carpeting with caution cannot be overemphasized. Membership of a political group/party should be backed by commitment to well defined ideologies and values. Commitment to them should be regarded akin to that found in the family, which is not easily or flippantly jettisoned.

Keywords: cross-carpeting, Nigeria, legal, moral issues, politics

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2354 Complicity of Religion in Legalizing Corruption: Perspective from an Emerging Economy

Authors: S. Opadere Olaolu

Abstract:

Religion, as a belief-system, has been with humanity for a long time. It has been recognised to impact the lives of individuals, groups, and communities that hold it dear. Whether the impact is regarded as positive or not depends on the assessor. Thus, for reasons of likely subjectiveness, possible irrationality, and even outright deliberate abuse, most emerging economies seek to follow the pattern of separating the State from religion; yet it is certain that the influence of religion on the State is incontrovertible. Corruption, on the other hand, though difficult to define in precise terms, is clearly perceptible. It could manifest in very diverse ways, including the abuse of a position of trust for the gain of an individual, or of a group with shared ulterior motive. Religion has been perceived, among others, as a means to societal stability, marital stability, infusion of moral rectitude, and conscience with regards to right and wrong. In time past, credible and dependable characters reposed largely and almost exclusively with those bearing deep religious conviction. Even in the political circle, it was thought that the involvement of those committed to religion would bring about positive changes, for the benefit of the society at large. On the contrary, in recent times, religion has failed in these lofty expectations. The level of corruption in most developing economies, and the increase of religion seem to be advancing pari passu. For instance, religion has encroached into political space, and vice versa, without any differentiable posture to the issue of corruption. Worse still, religion appears to be aiding and abetting corruption, overtly and/or covertly. Therefore, this discourse examined from the Nigerian perspective—as a developing economy—, and from a multidisciplinary stand-point of Law and Religion, the issue of religion; secularism; corruption; romance of religion and politics; inability of religion to exemplify moral rectitude; indulgence of corruption by religion; and the need to keep religion in private sphere, with proper checks. The study employed primary and secondary sources of information. The primary sources included the Constitutions of the Federal Republic of Nigeria 1999, as amended; judicial decisions; and the Bible. The secondary sources comprised of information from books, journals, newspapers, magazines and Internet documents. Data obtained from these sources were subjected to content analysis. Findings of this study include the breach of constitutional provisions to keep religion out of State affairs; failure of religion to curb corruption; outright indulgence of corruption by religion; and religion having become a political tool. In conclusion, it is considered apposite still to keep the State out of religion, and to seek enforcement of the constitutional provisions in this respect. The stamp of legality placed on overt and covert corruption by religion should be removed by all means.

Keywords: corruption, complicity, legalizing, religion

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2353 Inequality of Opportunities and Dropping Out of High School: Perspectives for Students from a Public School and a Private School in Brazil

Authors: Joyce Mary Adam

Abstract:

The subject of youth and education has been on the agenda of both public policies and specific education policies. In this sense, this work aims to discuss, based on the conceptions of social capital and cultural capital, the possibilities of elaborating and putting into practice the life projects they build during secondary school. The critical view brought by the concepts of social capital and cultural capital considers that in the school environment, those who have social capital and cultural capital have more tools to continue their projects, while those who do not have such capital will consequently have fewer opportunities, a fact that directly contributes to the perpetuation of social and educational inequality. When the "Life Project" is discussed under the sole responsibility of the students, it is clear that it is the students who must "take their responsibilities and decisions", their success or failure. From this point of view, the success of the implementation of the Life Project is determined by how well the students have developed their "skills and competences" and their capacity for entrepreneurship, without promoting a critical reflection on the real economic difficulties of the majority of students at this level of education. This situation gives rise to feelings of self-blame and self-responsibility among young people, who are compelled to confront the reality that their expectations have not been fulfilled, that they have been unable to gain employment, and, in some instances, that they have been marginalized. In this regard, the research project aimed to gather data on the living conditions of students at a public school and a private school in Brazil through interviews. The research methodology were interviews with students from a public school and an elite private school. The main objective of the research was to analyze the students' cultural and social capital as a key element in their social and professional integration after completing this stage of education. The study showed that social and cultural capital has a significant influence on opportunities to continue studying or to find a satisfactory job. For young people from public schools, from lower economic classes, the need to enter the job market as soon as they finish or even before they finish high school is due to economic and survival issues. The hours of dedication to studies and the diversity of cultural activities such as trips, visits to museums or the cultivation of artistic activities available to poorer students in state schools has proved to be rarer. In conclusion, we found that the difference in social and cultural capital between the young people taking part in the research has been shown to play an important role in the social and professional integration of the students and contributes to the maintenance of school and social inequality. This highlights the importance of public policies and support networks for young people leaving secondary school.

Keywords: social capital, cultural capital, high school, life project, social insertion, professional insertion, youth

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2352 Oligoalkylamine Modified Poly(Amidoamine) Generation 4.5 Dendrimer for the Delivery of Small Interfering RNA

Authors: Endris Yibru Hanurry, Wei-Hsin Hsu, Hsieh-Chih Tsai

Abstract:

In recent years, the discovery of small interfering RNAs (siRNAs) has got great attention for the treatment of cancer and other diseases. However, the therapeutic efficacy of siRNAs has been faced with many drawbacks because of short half-life in blood circulation, poor membrane penetration, weak endosomal escape and inadequate release into the cytosol. To overcome these drawbacks, we designed a non-viral vector by conjugating polyamidoamine generation 4.5 dendrimer (PDG4.5) with diethylenetriamine (DETA)- and tetraethylenepentamine (TEPA) followed by binding with siRNA to form polyplexes through electrostatic interaction. The result of 1H nuclear magnetic resonance (NMR), 13C NMR, correlation spectroscopy, heteronuclear single–quantum correlation spectroscopy, and Fourier transform infrared spectroscopy confirmed the successful conjugation of DETA and TEPA with PDG4.5. Then, the size, surface charge, morphology, binding ability, stability, release assay, toxicity and cellular internalization were analyzed to explore the physicochemical and biological properties of PDG4.5-DETA and PDG4.5-TEPA polyplexes at specific N/P ratios. The polyplexes (N/P = 8) exhibited spherical nanosized (125 and 85 nm) particles with optimum surface charge (13 and 26 mV), showed strong siRNA binding ability, protected the siRNA against enzyme digestion and accepted biocompatibility to the HeLa cells. Qualitatively, the fluorescence microscopy image revealed the delocalization (Manders’ coefficient 0.63 and 0.53 for PDG4.5-DETA and PDG4.5-TEPA, respectively) of polyplexes and the translocation of the siRNA throughout the cytosol to show a decent cellular internalization and intracellular biodistribution of polyplexes in HeLa cells. Quantitatively, the flow cytometry result indicated that a significant (P < 0.05) amount of siRNA was internalized by cells treated with PDG4.5-DETA (68.5%) and PDG4.5-TEPA (73%) polyplexes. Generally, PDG4.5-DETA and PDG4.5-TEPA were ideal nanocarriers of siRNA in vitro and might be used as promising candidates for in vivo study and future pharmaceutical applications.

Keywords: non-viral carrier, oligoalkylamine, poly(amidoamine) dendrimer, polyplexes, siRNA

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2351 Vagal Nerve Stimulator as a Treatment Approach in CHARGE Syndrome: A Case Report

Authors: Roya Vakili, Lekaa Elhajjmoussa, Barzin Omidi-Shal, Kim Blake

Abstract:

Objective: The purpose of this case report is to highlight the successful treatment of a patient with Coloboma, Heart defect, Atresia choanae, Retarded growth and development, Genital hypoplasia, Ear anomalies/deafness, (CHARGE syndrome) using a vagal nerve stimulator (VNS). Background: This is the first documented case report, to the authors' best knowledge, for a patient with CHARGE syndrome, epilepsy, autism, and postural orthostatic tachycardia syndrome (POTS) that was successfully treated with an implanted VNS therapeutic device. Methodology: The study is a case report. Results: This is the case of a 24-year-old female patient with CHARGE syndrome (non-random association of anomalies Coloboma, Heart defect, Atresia choanae, Retarded growth and development, Genital hypoplasia, Ear anomalies/deafness) and several other comorbidities including refractory epilepsy, Patent Ductus Arteriosus (PDA) and POTS who had significant improvement of her symptoms after VNS implantation. She was a VNS candidate given her longstanding history of drug-resistant epilepsy and current disposition secondary to CHARGE syndrome. Prior to VNS implantation, she experienced three generalized seizures a year and daily POTS-related symptoms. She was having frequent lightheadedness and syncope spells due to a rapid heart rate and low blood pressure. The VNS device was set to detect a rapid heart rate and send appropriate stimulation anytime the heart rate exceeded 20% of the patient’s normal baseline. The VNS device demonstrated frequent elevated heart rates and concurrent VNS release every 8 minutes in addition to the programmed events. Following VNS installation, the patient became more active, alert, and communicative and was able to verbally communicate with words she was unable to say prior. Her GI symptoms also improved, as she was able to tolerate food better orally in addition to her G and J tube, likely another result of the vagal nerve stimulation. Additionally, the patient’s seizures and POTS-related cardiac events appeared to be well controlled. She had prolonged electroencephalogram (EEG) testing, showing no significant change in epileptiform activity. Improvements in the patient’s disposition are believed to be secondary to parasympathetic stimulation, adequate heart rate control, and GI stimulation, in addition to behavioral changes and other benefits via her implanted VNS. Conclusion: VNS showed promising results in improving the patient's quality of life and managing her diverse symptoms, including dysautonomia, POTs, gastrointestinal mobility, cognitive functioning as well seizure control.

Keywords: autism, POTs, CHARGE, VNS

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2350 Hydro-Meteorological Vulnerability and Planning in Urban Area: The Case of Yaoundé City in Cameroon

Authors: Ouabo Emmanuel Romaric, Amougou Armathe

Abstract:

Background and aim: The study of impacts of floods and landslides at a small scale, specifically in the urban areas of developing countries is done to provide tools and actors for a better management of risks in such areas, which are now being affected by climate change. The main objective of this study is to assess the hydrometeorological vulnerabilities associated with flooding and urban landslides to propose adaptation measures. Methods: Climatic data analyses were done by calculation of indices of climate change within 50 years (1960-2012). Analyses of field data to determine causes, the level of risk and its consequences on the area of study was carried out using SPSS 18 software. The cartographic analysis and GIS were used to refine the work in space. Then, spatial and terrain analyses were carried out to determine the morphology of field in relation with floods and landslide, and the diffusion on the field. Results: The interannual changes in precipitation has highlighted the surplus years (21), the deficit years (24) and normal years (7). Barakat method bring out evolution of precipitation by jerks and jumps. Floods and landslides are correlated to high precipitation during surplus and normal years. Data field analyses show that populations are conscious (78%) of the risks with 74% of them exposed, but their capacities of adaptation is very low (51%). Floods are the main risk. The soils are classed as feralitic (80%), hydromorphic (15%) and raw mineral (5%). Slope variation (5% to 15%) of small hills and deep valley with anarchic construction favor flood and landslide during heavy precipitation. Mismanagement of waste produce blocks free circulation of river and accentuate floods. Conclusion: Vulnerability of population to hydrometeorological risks in Yaoundé VI is the combination of variation of parameters like precipitation, temperature due to climate change, and the bad planning of construction in urban areas. Because of lack of channels for water to circulate due to saturation of soils, the increase of heavy precipitation and mismanagement of waste, the result are floods and landslides which causes many damages on goods and people.

Keywords: climate change, floods, hydrometeorological, vulnerability

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2349 Comparison of Chemical Coagulation and Electrocoagulation for Boron Removal from Synthetic Wastewater Using Aluminium

Authors: Kartikaningsih Danis, Yao-Hui Huang

Abstract:

Various techniques including conventional and advanced have been employed for the boron treatment from water and wastewater. The electrocoagulation involves an electrolytic reactor for coagulation/flotation with aluminium as anode and cathode. There is aluminium as coagulant to be used for removal which may induce secondary pollution in chemical coagulation. The purpose of this study is to investigate and compare the performance between electrocoagulation and chemical coagulation on boron removal from synthetic wastewater. The effect of different parameters, such as pH reaction, coagulant dosage, and initial boron concentration were examined. The results show that the boron removal using chemical coagulation was lower. At the optimum condition (e.g. pH 8 and 0.8 mol coagulant dosage), boron removal efficiencies for chemical coagulation and electrocoagulation were 61% and 91%, respectively. In addition, the electrocoagulation needs no chemical reagents and makes the boron treatment easy for application.

Keywords: boron removal, chemical coagulation, aluminum, electro-coagulation

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2348 Fluorescence Sensing as a Tool to Estimate Palm Oil Quality and Yield

Authors: Norul Husna A. Kasim, Siva K. Balasundram

Abstract:

The gap between ‘actual yield’ and ‘potential yield’ has remained a problem in the Malaysian oil palm industry. Ineffective maturity assessment and untimely harvesting have compounded this problem. Typically, the traditional method of palm oil quality and yield assessment is destructive, costly and laborious. Fluorescence-sensing offers a new means of assessing palm oil quality and yield non-destructively. This work describes the estimation of palm oil quality and yield using a multi-parametric fluorescence sensor (Multiplex®) to quantify the concentration of secondary metabolites, such as anthocyanin and flavonoid, in fresh fruit bunches across three different palm ages (6, 9, and 12 years-old). Results show that fluorescence sensing is an effective means of assessing FFB maturity, in terms of palm oil quality and yield quantifications.

Keywords: anthocyanin, flavonoid fluorescence sensor, palm oil yield and quality

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2347 COVID-19 Case: A Definition of Infodemia through Online Italian Journalism

Authors: Concetta Papapicco

Abstract:

The spreading of new Coronavirus (COVID-19) in addition to becoming a global phenomenon, following the declaration of a pandemic state, has generated excessive access to information, sometimes not thoroughly screened, which makes it difficult to navigate a given topic because of the difficulty of finding reliable sources. As a result, there is a high level of contagion, understood as the spread of the virus, but also as the spread of information in a viral and harmful way, which prompted the World Health Organization to coin the term Infodemia to give 'a name' the phenomenon of excessive information. With neologism 'Infodemia', the World Health Organization (OMS) wanted, in these days when fear of the coronavirus is raging, point out that perhaps the greatest danger of global society in the age of social media. This phenomenon is the distortion of reality in the rumble of echoes and comments of the global community on real or often invented facts. The general purpose of the exploratory study is to investigate how the coronavirus situation is described from journalistic communication. Starting from La Repubblica online, as a reference journalistic magazine, as a specific objective, the research aims to understand the way in which journalistic communication describes the phenomenon of the COVID-19 virus spread, the spread of contagion and restrictive measures of social distancing in the Italian context. The study starts from the hypothesis that if the circulation of information helps to create a social representation of the phenomenon, the excessive accessibility to sources of information (Infodemia) can be modulated by the 'how' the phenomenon is described by the journalists. The methodology proposed, in fact, in the exploratory study is a quanti-qualitative (mixed) method. A Content Analysis with the SketchEngine software is carried out first. In support of the Content Analysis, a Diatextual Analysis was carried out. The Diatextual Analysis is a qualitative analysis useful to detect in the analyzed texts, that is the online articles of La Repubblica on the topic of coronavirus, Subjectivity, Argomentativity, and Mode. The research focuses mainly on 'Mode' or 'How' are the events related to coronavirus in the online articles of La Repubblica about COVID-19 phenomenon. The results show the presence of the contrast vision about COVID-19 situation in Italy.

Keywords: coronavirus, Italian infodemia, La Republica online, mix method

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2346 Logic of the Prospect Theory: The Decision Making Process of the First Gulf War and the Crimean Annexation

Authors: Zhengyang Ma, Zhiyao Li, Jiayi Zhang

Abstract:

This article examines the prospect theory’s arguments about decision-making through two case studies, the First Gulf War and Russia’s annexation of Crimea. The article uses the methods of comparative case analysis and process tracing to investigate the prospect theory’s fundamental arguments. Through evidence derived from existing primary and secondary sources, this paper argues that both former U.S. President Bush and Russian President Putin viewed their situations as a domain of loss and made risky decisions to prevent further deterioration, which attests the arguments of the prospect theory. After the two case studies, this article also discusses how the prospect theory could be used in analyzing the decision-making process that led to the current Russia-Ukraine War.

Keywords: the prospect theory, international relations, the first gulf war, the crimea crisis

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2345 The Names of the Traditional Motif of Batik Solo

Authors: Annisa D. Febryandini

Abstract:

Batik is a unique cultural heritage that strongly linked with its community. As a product of current culture in Solo, Batik Solo not only has a specific design and color to represent the cultural identity, cultural values, and spirituality of the community, but also has some specific names given by its community which are not arbitrary. This qualitative research paper uses the primary data by interview method as well as the secondary data to support it. Based on the data, this paper concludes that the names consist of a word or words taken from a current name of things in Javanese language. They indicate the cultural meaning such as a specific event, a hope, and the social status of the people who use the motif. Different from the other research, this paper takes a look at the names of traditional motif of Batik Solo which analyzed linguistically to reveal the cultural meaning.

Keywords: traditional motif, Batik, solo, anthropological linguistics

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2344 The Water-Way Route Management for Cultural Tourism Promotion at Angsila District: Challenge and Opportunity

Authors: Teera Intararuang

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The purpose of this research is to study on the challenge and opportunity for waterway route management for promoting cultural tourism in Angsila District, Chonburi Province. To accomplish the goals and objectives, qualitative research will be applied. The research instruments used are observation, basic interviews, in-depth interviews, and interview key local performance. The study also uses both primary data and secondary data. From research result, it is revealed that all respondents had appreciated and strongly agree to promote their waterway route tourism as an intend for further increase for their income. However, it has some challenges to success this project due to natural obstacles such as water level, seasons and high temperature. Moreover, they lack financial support from government sectors also.

Keywords: Angsila community, waterway tourism route, cultural tourism, way of life

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2343 The Effect of Lead(II) Lone Electron Pair and Non-Covalent Interactions on the Supramolecular Assembly and Fluorescence Properties of Pb(II)-Pyrrole-2-Carboxylato Polymer

Authors: M. Kowalik, J. Masternak, K. Kazimierczuk, O. V. Khavryuchenko, B. Kupcewicz, B. Barszcz

Abstract:

Recently, the growing interest of chemists in metal-organic coordination polymers (MOCPs) is primarily derived from their intriguing structures and potential applications in catalysis, gas storage, molecular sensing, ion exchanges, nonlinear optics, luminescence, etc. Currently, we are devoting considerable effort to finding the proper method of synthesizing new coordination polymers containing S- or N-heteroaromatic carboxylates as linkers and characterizing the obtained Pb(II) compounds according to their structural diversity, luminescence, and thermal properties. The choice of Pb(II) as the central ion of MOCPs was motivated by several reasons mentioned in the literature: i) a large ionic radius allowing for a wide range of coordination numbers, ii) the stereoactivity of the 6s2 lone electron pair leading to a hemidirected or holodirected geometry, iii) a flexible coordination environment, and iv) the possibility to form secondary bonds and unusual non-covalent interactions, such as classic hydrogen bonds and π···π stacking interactions, as well as nonconventional hydrogen bonds and rarely reported tetrel bonds, Pb(lone pair)···π interactions, C–H···Pb agostic-type interactions or hydrogen bonds, and chelate ring stacking interactions. Moreover, the construction of coordination polymers requires the selection of proper ligands acting as linkers, because we are looking for materials exhibiting different network topologies and fluorescence properties, which point to potential applications. The reaction of Pb(NO₃)₂ with 1H-pyrrole-2-carboxylic acid (2prCOOH) leads to the formation of a new four-nuclear Pb(II) polymer, [Pb4(2prCOO)₈(H₂O)]ₙ, which has been characterized by CHN, FT-IR, TG, PL and single-crystal X-ray diffraction methods. In view of the primary Pb–O bonds, Pb1 and Pb2 show hemidirected pentagonal pyramidal geometries, while Pb2 and Pb4 display hemidirected octahedral geometries. The topology of the strongest Pb–O bonds was determined as the (4·8²) fes topology. Taking the secondary Pb–O bonds into account, the coordination number of Pb centres increased, Pb1 exhibited a hemidirected monocapped pentagonal pyramidal geometry, Pb2 and Pb4 exhibited a holodirected tricapped trigonal prismatic geometry, and Pb3 exhibited a holodirected bicapped trigonal prismatic geometry. Moreover, the Pb(II) lone pair stereoactivity was confirmed by DFT calculations. The 2D structure was expanded into 3D by the existence of non-covalent O/C–H···π and Pb···π interactions, which was confirmed by the Hirshfeld surface analysis. The above mentioned interactions improve the rigidity of the structure and facilitate the charge and energy transfer between metal centres, making the polymer a promising luminescent compound.

Keywords: coordination polymers, fluorescence properties, lead(II), lone electron pair stereoactivity, non-covalent interactions

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2342 The Leaching Kinetics of Zinc from Industrial Zinc Slag Waste

Authors: Hilary Rutto

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The investigation was aimed at determining the extent at which the zinc will be extracted from secondary sources generated from galvanising process using dilute sulphuric acid under controlled laboratory conditions of temperature, solid-liquid ratio, and agitation rate. The leaching experiment was conducted for a period of 2 hours and to total zinc extracted calculated in relation to the amount of zinc dissolved at a unit time in comparison to the initial zinc content of the zinc ash. Sulphuric acid was found to be an effective leaching agent with an overall extraction of 91.1% when concentration is at 2M, and solid/liquid ratio kept at 1g/200mL leaching solution and temperature set at 65ᵒC while slurry agitation is at 450rpm. The leaching mechanism of zinc ash with sulphuric acid was conformed well to the shrinking core model.

Keywords: leaching, kinetics, shrinking core model, zinc slag

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