Search results for: high risk sex
1090 A Cross-Cultural Validation of the Simple Measure of Impact of Lupus Erythematosus in Youngsters (Smiley) among Filipino Pediatric Lupus Patients
Authors: Jemely M. Punzalan, Christine B. Bernal, Beatrice B. Canonigo, Maria Rosario F. Cabansag, Dennis S. Flores, Paul Joseph T. Galutira, Remedios D. Chan
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Background: Systemic lupus erythematosus (SLE) is one of the most common autoimmune disorders predominates in women of childbearing age. Simple Measure of Impact of Lupus Erythematosus in Youngsters (SMILEY) is the only health specific quality of life tool for pediatric SLE, which has been translated to different languages except in Filipino. Objective: The primary objective of this study was to develop a Filipino translation of the SMILEY and to examine the validity and reliability of this translation. Methodology: The SMILEY was translated into Filipino by a bilingual individual and back-translated by another bilingual individual blinded from the original English version. The translation was evaluated for content validity by a panel of experts and subjected to pilot testing. The pilot-tested translation was used in the validity and reliability testing proper. The SMILEY, together with the previously validated PEDSQL 4.0 Generic Core Scale was administered to lupus pediatric patients and their parent at two separate occasions: a baseline and a re-test seven to fourteen days apart. Tests for convergent validity, internal consistency, and test-retest reliability were performed. Results: A total of fifty children and their parent were recruited. The mean age was 15.38±2.62 years (range 8-18 years), mean education at high school level. The mean duration of SLE was 28 months (range 1-81 months). Subjects found the questionnaires to be relevant, easy to understand and answer. The validity of the SMILEY was demonstrated in terms of content validity, convergent validity, internal consistency, and test-retest reliability. Age, socioeconomic status and educational attainment did not show a significant effect on the scores. The difference between scores of child and parent report was showed to be significant with SMILEY total (p=0.0214), effect on social life (p=0.0000), and PEDSQL physical function (p=0.0460). Child reports showed higher scores for the following domains compared to their parent. Conclusion: SMILEY is a brief, easy to understand, valid and reliable tool for assessing pediatric SLE specific HRQOL. It will be useful in providing better care, understanding and may offer critical information regarding the effect of SLE in the quality of life of our pediatric lupus patients. It will help physician understands the needs of their patient not only on treatment of the specific disease but as well as the impact of the treatment on their daily lives.Keywords: systemic lupus erythematosus, pediatrics, quality of life, Simple Measure of Impact of Lupus Erythematosus in Youngsters (SMILEY)
Procedia PDF Downloads 4351089 Targeted Delivery of Docetaxel Drug Using Cetuximab Conjugated Vitamin E TPGS Micelles Increases the Anti-Tumor Efficacy and Inhibit Migration of MDA-MB-231 Triple Negative Breast Cancer
Authors: V. K. Rajaletchumy, S. L. Chia, M. I. Setyawati, M. S. Muthu, S. S. Feng, D. T. Leong
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Triple negative breast cancers (TNBC) can be classified as one of the most aggressive with a high rate of local recurrences and systematic metastases. TNBCs are insensitive to existing hormonal therapy or targeted therapies such as the use of monoclonal antibodies, due to the lack of oestrogen receptor (ER) and progesterone receptor (PR) and the absence of overexpression of human epidermal growth factor receptor 2 (HER2) compared with other types of breast cancers. The absence of targeted therapies for selective delivery of therapeutic agents into tumours, led to the search for druggable targets in TNBC. In this study, we developed a targeted micellar system of cetuximab-conjugated micelles of D-α-tocopheryl polyethylene glycol succinate (vitamin E TPGS) for targeted delivery of docetaxel as a model anticancer drug for the treatment of TNBCs. We examined the efficacy of our micellar system in xenograft models of triple negative breast cancers and explored the effect of the micelles on post-treatment tumours in order to elucidate the mechanism underlying the nanomedicine treatment in oncology. The targeting micelles were found preferentially accumulated in tumours immediately after the administration of the micelles compare to normal tissue. The fluorescence signal gradually increased up to 12 h at the tumour site and sustained for up to 24 h, reflecting the increases in targeted micelles (TPFC) micelles in MDA-MB-231/Luc cells. In comparison, for the non-targeting micelles (TPF), the fluorescence signal was evenly distributed all over the body of the mice. Only a slight increase in fluorescence at the chest area was observed after 24 h post-injection, reflecting the moderate uptake of micelles by the tumour. The successful delivery of docetaxel into tumour by the targeted micelles (TPDC) exhibited a greater degree of tumour growth inhibition than Taxotere® after 15 days of treatment. The ex vivo study has demonstrated that tumours treated with targeting micelles exhibit enhanced cell cycle arrest and attenuated proliferation compared with the control and with those treated non-targeting micelles. Furthermore, the ex vivo investigation revealed that both the targeting and non-targeting micellar formulations shows significant inhibition of cell migration with migration indices reduced by 0.098- and 0.28-fold, respectively, relative to the control. Overall, both the in vivo and ex vivo data increased the confidence that our micellar formulations effectively targeted and inhibited EGF-overexpressing MDA-MB-231 tumours.Keywords: biodegradable polymers, cancer nanotechnology, drug targeting, molecular biomaterials, nanomedicine
Procedia PDF Downloads 2761088 The Solid-Phase Sensor Systems for Fluorescent and SERS-Recognition of Neurotransmitters for Their Visualization and Determination in Biomaterials
Authors: Irina Veselova, Maria Makedonskaya, Olga Eremina, Alexandr Sidorov, Eugene Goodilin, Tatyana Shekhovtsova
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Such catecholamines as dopamine, norepinephrine, and epinephrine are the principal neurotransmitters in the sympathetic nervous system. Catecholamines and their metabolites are considered to be important markers of socially significant diseases such as atherosclerosis, diabetes, coronary heart disease, carcinogenesis, Alzheimer's and Parkinson's diseases. Currently, neurotransmitters can be studied via electrochemical and chromatographic techniques that allow their characterizing and quantification, although these techniques can only provide crude spatial information. Besides, the difficulty of catecholamine determination in biological materials is associated with their low normal concentrations (~ 1 nM) in biomaterials, which may become even one more order lower because of some disorders. In addition, in blood they are rapidly oxidized by monoaminooxidases from thrombocytes and, for this reason, the determination of neurotransmitter metabolism indicators in an organism should be very rapid (15—30 min), especially in critical states. Unfortunately, modern instrumental analysis does not offer a complex solution of this problem: despite its high sensitivity and selectivity, HPLC-MS cannot provide sufficiently rapid analysis, while enzymatic biosensors and immunoassays for the determination of the considered analytes lack sufficient sensitivity and reproducibility. Fluorescent and SERS-sensors remain a compelling technology for approaching the general problem of selective neurotransmitter detection. In recent years, a number of catecholamine sensors have been reported including RNA aptamers, fluorescent ribonucleopeptide (RNP) complexes, and boronic acid based synthetic receptors and the sensor operated in a turn-off mode. In this work we present the fluorescent and SERS turn-on sensor systems based on the bio- or chemorecognizing nanostructured films {chitosan/collagen-Tb/Eu/Cu-nanoparticles-indicator reagents} that provide the selective recognition, visualization, and sensing of the above mentioned catecholamines on the level of nanomolar concentrations in biomaterials (cell cultures, tissue etc.). We have (1) developed optically transparent porous films and gels of chitosan/collagen; (2) ensured functionalization of the surface by molecules-'recognizers' (by impregnation and immobilization of components of the indicator systems: biorecognizing and auxiliary reagents); (3) performed computer simulation for theoretical prediction and interpretation of some properties of the developed materials and obtained analytical signals in biomaterials. We are grateful for the financial support of this research from Russian Foundation for Basic Research (grants no. 15-03-05064 a, and 15-29-01330 ofi_m).Keywords: biomaterials, fluorescent and SERS-recognition, neurotransmitters, solid-phase turn-on sensor system
Procedia PDF Downloads 4001087 Solar Electric Propulsion: The Future of Deep Space Exploration
Authors: Abhishek Sharma, Arnab Banerjee
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The research is intended to study the solar electric propulsion (SEP) technology for planetary missions. The main benefits of using solar electric propulsion for such missions are shorter flight times, more frequent target accessibility and the use of a smaller launch vehicle than that required by a comparable chemical propulsion mission. Energized by electric power from on-board solar arrays, the electrically propelled system uses 10 times less propellant than conventional chemical propulsion system, yet the reduced fuel mass can provide vigorous power which is capable of propelling robotic and crewed missions beyond the Lower Earth Orbit (LEO). The various thrusters used in the SEP are gridded ion thrusters and the Hall Effect thrusters. The research is solely aimed to study the ion thrusters and investigate the complications related to it and what can be done to overcome the glitches. The ion thrusters are used because they are found to have a total lower propellant requirement and have substantially longer time. In the ion thrusters, the anode pushes or directs the incoming electrons from the cathode. But the anode is not maintained at a very high potential which leads to divergence. Divergence leads to the charges interacting against the surface of the thruster. Just as the charges ionize the xenon gases, they are capable of ionizing the surfaces and over time destroy the surface and hence contaminate it. Hence the lifetime of thruster gets limited. So a solution to this problem is using substances which are not easy to ionize as the surface material. Another approach can be to increase the potential of anode so that the electrons don’t deviate much or reduce the length of thruster such that the positive anode is more effective. The aim is to work on these aspects as to how constriction of the deviation of charges can be done by keeping the input power constant and hence increase the lifetime of the thruster. Predominantly ring cusp magnets are used in the ion thrusters. However, the study is also intended to observe the effect of using solenoid for producing micro-solenoidal magnetic field apart from using the ring cusp magnetic field which are used in the discharge chamber for prevention of interaction of electrons with the ionization walls. Another foremost area of interest is what are the ways by which power can be provided to the Solar Electric Propulsion Vehicle for lowering and boosting the orbit of the spacecraft and also provide substantial amount of power to the solenoid for producing stronger magnetic fields. This can be successfully achieved by using the concept of Electro-dynamic tether which will serve as a power source for powering both the vehicle and the solenoids in the ion thruster and hence eliminating the need for carrying extra propellant on the spacecraft which will reduce the weight and hence reduce the cost of space propulsion.Keywords: electro-dynamic tether, ion thruster, lifetime of thruster, solar electric propulsion vehicle
Procedia PDF Downloads 2061086 Characterization of Phenolic Compounds from Carménère Wines during Aging with Oak Wood (Staves, Chips and Barrels)
Authors: E. Obreque-Slier, J. Laqui-Estaña, A. Peña-Neira, M. Medel-Marabolí
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Wine is an important source of polyphenols. Red wines show important concentrations of nonflavonoid (gallic acid, ellagic acid, caffeic acid and coumaric acid) and flavonoid compounds [(+)-catechin, (-)-epicatechin, (+)-gallocatechin and (-)-epigallocatechin]. However, a significant variability in the quantitative and qualitative distribution of chemical constituents in wine has to be expected depending on an array of important factors, such as the varietal differences of Vitis vinifera and cultural practices. It has observed that Carménère grapes present a differential composition and evolution of phenolic compounds when compared to other varieties and specifically with Cabernet Sauvignon grapes. Likewise, among the cultural practices, the aging in contact with oak wood is a high relevance factor. Then, the extraction of different polyphenolic compounds from oak wood into wine during its ageing process produces both qualitative and quantitative changes. Recently, many new techniques have been introduced in winemaking. One of these involves putting new pieces of wood (oak chips or inner staves) into inert containers. It offers some distinct and previously unavailable flavour advantages, as well as new options in wine handling. To our best knowledge, there is not information about the behaviour of Carménère wines (Chilean emblematic cultivar) in contact with oak wood. In addition, the effect of aging time and wood product (barrels, chips or staves) on the phenolic composition in Carménère wines has not been studied. This study aims at characterizing the condensed and hydrolyzable tannins from Carménère wines during the aging with staves, chips and barrels from French oak wood. The experimental design was completely randomized with two independent assays: aging time (0-12 month) and different formats of wood (barrel, chips and staves). The wines were characterized by spectrophotometric (total tannins and fractionation of proanthocyanidins into monomers, oligomers and polymers) and HPLC-DAD (ellagitannins) analysis. The wines in contact with different products of oak wood showed a similar content of total tannins during the study, while the control wine (without oak wood) presented a lower content of these compounds. In addition, it was observed that the polymeric proanthocyanidin fraction was the most abundant, while the monomeric fraction was the less abundant fraction in all treatments in two sample. However, significative differences in each fractions were observed between wines in contact from barrel, chips, and staves in two sample dates. Finally, the wine from barrels presented the highest content of the ellagitannins from the fourth to the last sample date. In conclusion, the use of alternative formats of oak wood affects the chemical composition of wines during aging, and these enological products are an interesting alternative to contribute with tannins to wine.Keywords: enological inputs, oak wood aging, polyphenols, red wine
Procedia PDF Downloads 1541085 Preparation of Papers - Developing a Leukemia Diagnostic System Based on Hybrid Deep Learning Architectures in Actual Clinical Environments
Authors: Skyler Kim
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An early diagnosis of leukemia has always been a challenge to doctors and hematologists. On a worldwide basis, it was reported that there were approximately 350,000 new cases in 2012, and diagnosing leukemia was time-consuming and inefficient because of an endemic shortage of flow cytometry equipment in current clinical practice. As the number of medical diagnosis tools increased and a large volume of high-quality data was produced, there was an urgent need for more advanced data analysis methods. One of these methods was the AI approach. This approach has become a major trend in recent years, and several research groups have been working on developing these diagnostic models. However, designing and implementing a leukemia diagnostic system in real clinical environments based on a deep learning approach with larger sets remains complex. Leukemia is a major hematological malignancy that results in mortality and morbidity throughout different ages. We decided to select acute lymphocytic leukemia to develop our diagnostic system since acute lymphocytic leukemia is the most common type of leukemia, accounting for 74% of all children diagnosed with leukemia. The results from this development work can be applied to all other types of leukemia. To develop our model, the Kaggle dataset was used, which consists of 15135 total images, 8491 of these are images of abnormal cells, and 5398 images are normal. In this paper, we design and implement a leukemia diagnostic system in a real clinical environment based on deep learning approaches with larger sets. The proposed diagnostic system has the function of detecting and classifying leukemia. Different from other AI approaches, we explore hybrid architectures to improve the current performance. First, we developed two independent convolutional neural network models: VGG19 and ResNet50. Then, using both VGG19 and ResNet50, we developed a hybrid deep learning architecture employing transfer learning techniques to extract features from each input image. In our approach, fusing the features from specific abstraction layers can be deemed as auxiliary features and lead to further improvement of the classification accuracy. In this approach, features extracted from the lower levels are combined into higher dimension feature maps to help improve the discriminative capability of intermediate features and also overcome the problem of network gradient vanishing or exploding. By comparing VGG19 and ResNet50 and the proposed hybrid model, we concluded that the hybrid model had a significant advantage in accuracy. The detailed results of each model’s performance and their pros and cons will be presented in the conference.Keywords: acute lymphoblastic leukemia, hybrid model, leukemia diagnostic system, machine learning
Procedia PDF Downloads 1811084 Pregnancy Outcomes in Women With History of COVID-19 in Alexandria, Egypt
Authors: Nermeen Elbeltagy, Helmy abd Elsatar, Sara Hassan, Mohamed Darwish
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Introduction: with the inial appearance in Wuhan, China, in December 2019, the coronavirus disease-related respiratory infection (COVID-19) has rapidly spread among people all over the world. The WHO considered it a pandemic in March 2020. The severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV) outbreaks have proved that pregnant females as well as their fetuses are exposed to adverse outcomes, including high rates of intensive care unit (ICU) admission and case fatality. Physiological changes occurring during pregnancy such as the increased transverse diameter of the thoracic cage as well as the elevation of the diaphragm can expose the mother to severe infections because of her decreased tolerance for hypoxia. Furthermore, vasodilation and changes in lung capacity can cause mucosal edema and an increase in upper respiratory tract secretions. In addition, the increased susceptibility to infection is enhanced by changes in cellmediated immunity. Aim of the work: to study the effect of COVID-19 on pregnant females admitted to El-Shatby Maternity University Hospital regarding maternal antepartum, intrapartum and postpartum adverse effects on the mothers and their neonates. Method: A retrospective cohort study was done between October 2020 and October 2022. Maternal characteristics and associated health conditions of COVID-19 positive parents were investigated. Also, the severity of their conditions and me of infection (first or second or third trimester)were explored. Cases were diagnosed based on presence of symptoms suggestive of COVID-19, laboratory tests (other than PCR) and radiological findings.all cases were confirmed by positive PCR test results. Results: The most common adverse maternal outcomes were pre-term labor (11.6%) followed by premature rupture of membranes (5.7%), post-partum hemorrhage (5.4%), preeclampsia (5.0%) and placental abrupon (4.3%). One sixth of the neonates of the studied paents were admied to NICUs and 6.5% of them had respiratory distress with no neonatal deaths. The majority of neonates (85.4%) had a birth weight of 2500- 4000g (normal range). Most of the neonates (77.9%) had an APGAR score of equal or more than 7 in 5 minutes. Conclusion: the most common comorbidity that might increase the incidence of COVID-19 before pregnancy were diabetes, cardiac disorders/ chronic hypertension and chronic obstructive lung diseases (non-asthma). During pregnancy, anemia followed by gestational diabetes and pre-eclampsia/gestational hypertension were the most prevalent comorbidity. So, severity of infection can be reduced by good antenatal care.Keywords: COVID-19, pregnancy outcome, complicated pregnancy., COVID in Egypt
Procedia PDF Downloads 721083 Assumption of Cognitive Goals in Science Learning
Authors: Mihail Calalb
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The aim of this research is to identify ways for achieving sustainable conceptual understanding within science lessons. For this purpose, a set of teaching and learning strategies, parts of the theory of visible teaching and learning (VTL), is studied. As a result, a new didactic approach named "learning by being" is proposed and its correlation with educational paradigms existing nowadays in science teaching domain is analysed. In the context of VTL the author describes the main strategies of "learning by being" such as guided self-scaffolding, structuring of information, and recurrent use of previous knowledge or help seeking. Due to the synergy effect of these learning strategies applied simultaneously in class, the impact factor of learning by being on cognitive achievement of students is up to 93 % (the benchmark level is equal to 40% when an experienced teacher applies permanently the same conventional strategy during two academic years). The key idea in "learning by being" is the assumption by the student of cognitive goals. From this perspective, the article discusses the role of student’s personal learning effort within several teaching strategies employed in VTL. The research results emphasize that three mandatory student – related moments are present in each constructivist teaching approach: a) students’ personal learning effort, b) student – teacher mutual feedback and c) metacognition. Thus, a successful educational strategy will target to achieve an involvement degree of students into the class process as high as possible in order to make them not only know the learning objectives but also to assume them. In this way, we come to the ownership of cognitive goals or students’ deep intrinsic motivation. A series of approaches are inherent to the students’ ownership of cognitive goals: independent research (with an impact factor on cognitive achievement equal to 83% according to the results of VTL); knowledge of success criteria (impact factor – 113%); ability to reveal similarities and patterns (impact factor – 132%). Although it is generally accepted that the school is a public service, nonetheless it does not belong to entertainment industry and in most of cases the education declared as student – centered actually hides the central role of the teacher. Even if there is a proliferation of constructivist concepts, mainly at the level of science education research, we have to underline that conventional or frontal teaching, would never disappear. Research results show that no modern method can replace an experienced teacher with strong pedagogical content knowledge. Such a teacher will inspire and motivate his/her students to love and learn physics. The teacher is precisely the condensation point for an efficient didactic strategy – be it constructivist or conventional. In this way, we could speak about "hybridized teaching" where both the student and the teacher have their share of responsibility. In conclusion, the core of "learning by being" approach is guided learning effort that corresponds to the notion of teacher–student harmonic oscillator, when both things – guidance from teacher and student’s effort – are equally important.Keywords: conceptual understanding, learning by being, ownership of cognitive goals, science learning
Procedia PDF Downloads 1651082 Students’ Speech Anxiety in Blended Learning
Authors: Mary Jane B. Suarez
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Public speaking anxiety (PSA), also known as speech anxiety, is innumerably persistent in any traditional communication classes, especially for students who learn English as a second language. The speech anxiety intensifies when communication skills assessments have taken their toll in an online or a remote mode of learning due to the perils of the COVID-19 virus. Both teachers and students have experienced vast ambiguity on how to realize a still effective way to teach and learn speaking skills amidst the pandemic. Communication skills assessments like public speaking, oral presentations, and student reporting have defined their new meaning using Google Meet, Zoom, and other online platforms. Though using such technologies has paved for more creative ways for students to acquire and develop communication skills, the effectiveness of using such assessment tools stands in question. This mixed method study aimed to determine the factors that affected the public speaking skills of students in a communication class, to probe on the assessment gaps in assessing speaking skills of students attending online classes vis-à-vis the implementation of remote and blended modalities of learning, and to recommend ways on how to address the public speaking anxieties of students in performing a speaking task online and to bridge the assessment gaps based on the outcome of the study in order to achieve a smooth segue from online to on-ground instructions maneuvering towards a much better post-pandemic academic milieu. Using a convergent parallel design, both quantitative and qualitative data were reconciled by probing on the public speaking anxiety of students and the potential assessment gaps encountered in an online English communication class under remote and blended learning. There were four phases in applying the convergent parallel design. The first phase was the data collection, where both quantitative and qualitative data were collected using document reviews and focus group discussions. The second phase was data analysis, where quantitative data was treated using statistical testing, particularly frequency, percentage, and mean by using Microsoft Excel application and IBM Statistical Package for Social Sciences (SPSS) version 19, and qualitative data was examined using thematic analysis. The third phase was the merging of data analysis results to amalgamate varying comparisons between desired learning competencies versus the actual learning competencies of students. Finally, the fourth phase was the interpretation of merged data that led to the findings that there was a significantly high percentage of students' public speaking anxiety whenever students would deliver speaking tasks online. There were also assessment gaps identified by comparing the desired learning competencies of the formative and alternative assessments implemented and the actual speaking performances of students that showed evidence that public speaking anxiety of students was not properly identified and processed.Keywords: blended learning, communication skills assessment, public speaking anxiety, speech anxiety
Procedia PDF Downloads 971081 Processing, Nutritional Assessment and Sensory Evaluation of Bakery Products Prepared from Orange Fleshed Sweet Potatoes (OFSP) and Wheat Composite Flours
Authors: Hategekimana Jean Paul, Irakoze Josiane, Ishimweyizerwe Valentin, Iradukunda Dieudonne, Uwanyirigira Jeannette
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Orange fleshed sweet potatoes (OFSP) are highly grown and are available plenty in rural and urban local markets and its contribution in reduction of food insecurity in Rwanda is considerable. But the postharvest loss of this commodity is a critical challenge due to its high perishability. Several research activities have been conducted on how fresh food commodities can be transformed into extended shelf life food products for prevention of post-harvest losses. However, such activity was not yet well studied in Rwanda. The aim of the present study was the processing of backed products from (OFSP)combined with wheat composite flour and assess the nutritional content and consumer acceptability of new developed products. The perishability of OFSP and their related lack during off season can be eradicated by producing cake, doughnut and bread with OFSP puree or flour. The processing for doughnut and bread were made by making OFSP puree and other ingredients then a dough was made followed by frying and baking while for cake OFSP was dried through solar dryer to have a flour together with wheat flour and other ingredients to make dough cake and baking. For each product, one control and three experimental samples, (three products in three different ratios (30,40 and50%) of OFSP and the remaining percentage of wheat flour) were prepared. All samples including the control were analyzed for the consumer acceptability (sensory attributes). Most preferred samples (One sample for each product with its control sample and for each OFSP variety) were analyzed for nutritional composition along with control sample. The Cake from Terimbere variety and Bread from Gihingumukungu supplemented with 50% OFSP flour or Puree respectively were most acceptable except Doughnut from Vita variety which was highly accepted at 50% of OFSP supplementation. The moisture, ash, protein, fat, fiber, Total carbohydrate, Vitamin C, reducing sugar and minerals (Sodium, Potassium and Phosphorus.) content was different among products. Cake was rich in fibers (14.71%), protein (6.590%), and vitamin c(19.988mg/100g) compared to other samples while bread found to be rich in reducing sugar with 12.71mg/100g compared to cake and doughnut. Also doughnut was found to be rich in fat content with 6.89% compared to other samples. For sensory analysis, doughnut was highly accepted in ratio of 60:40 compared to other products while cake was least accepted at ratio of 50:50. The Proximate composition and minerals content of all the OFSP products were significantly higher as compared to the control samples.Keywords: post-harvest loss, OFSP products, wheat flour, sensory evaluation, proximate composition
Procedia PDF Downloads 581080 Finite Element Modeling and Analysis of Reinforced Concrete Coupled Shear Walls Strengthened with Externally Bonded Carbon Fiber Reinforced Polymer Composites
Authors: Sara Honarparast, Omar Chaallal
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Reinforced concrete (RC) coupled shear walls (CSWs) are very effective structural systems in resisting lateral loads due to winds and earthquakes and are particularly used in medium- to high-rise RC buildings. However, most of existing old RC structures were designed for gravity loads or lateral loads well below the loads specified in the current modern seismic international codes. These structures may behave in non-ductile manner due to poorly designed joints, insufficient shear reinforcement and inadequate anchorage length of the reinforcing bars. This has been the main impetus to investigate an appropriate strengthening method to address or attenuate the deficiencies of these structures. The objective of this paper is to twofold: (i) evaluate the seismic performance of existing reinforced concrete coupled shear walls under reversed cyclic loading; and (ii) investigate the seismic performance of RC CSWs strengthened with externally bonded (EB) carbon fiber reinforced polymer (CFRP) sheets. To this end, two CSWs were considered as follows: (a) the first one is representative of old CSWs and therefore was designed according to the 1941 National Building Code of Canada (NBCC, 1941) with conventionally reinforced coupling beams; and (b) the second one, representative of new CSWs, was designed according to modern NBCC 2015 and CSA/A23.3 2014 requirements with diagonally reinforced coupling beam. Both CSWs were simulated using ANSYS software. Nonlinear behavior of concrete is modeled using multilinear isotropic hardening through a multilinear stress strain curve. The elastic-perfectly plastic stress-strain curve is used to simulate the steel material. Bond stress–slip is modeled between concrete and steel reinforcement in conventional coupling beam rather than considering perfect bond to better represent the slip of the steel bars observed in the coupling beams of these CSWs. The old-designed CSW was strengthened using CFRP sheets bonded to the concrete substrate and the interface was modeled using an adhesive layer. The behavior of CFRP material is considered linear elastic up to failure. After simulating the loading and boundary conditions, the specimens are analyzed under reversed cyclic loading. The comparison of results obtained for the two unstrengthened CSWs and the one retrofitted with EB CFRP sheets reveals that the strengthening method improves the seismic performance in terms of strength, ductility, and energy dissipation capacity.Keywords: carbon fiber reinforced polymer, coupled shear wall, coupling beam, finite element analysis, modern code, old code, strengthening
Procedia PDF Downloads 1931079 The Lack of Female Representation in Senior Positions: An Exploratory Study between South Africa and India
Authors: Dina Maria Smit
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Worldwide, it seems as if women are adequately represented in government and parliament but are almost absent from governing boards of private enterprises. The reasons for this seem to be embedded in perceptions of inadequacy, remnants of patriarchy, glass ceilings and even female choice. Direct or indirect discrimination against females have been found to be one of the reasons that female employees are found in traditionally “softer” roles, whilst the old “Boy’s Club” is still operational to keep women out of senior managerial positions, especially in the private sector. The cultural construct of Indian society, focusing on male preference, patriarchy, divorce laws and low educational levels of females as opposed to men, is indicative of a society wherein high gender inequality still exists. The position in South Africa is similar in that substantive gender equality has not been reached despite a progressive constitution and anti-discrimination laws. There is a strong push to propel women to senior positions in South Africa, but these efforts have not yet translated into females taking up senior positions in private companies. In South Africa, females still earn less than their male counterparts whilst performing doing the same jobs, are overrepresented in parliament, but do not captain the ships in the private sector. The lack of female parity in employment leads to a lack of autonomy and authority in both South Africa and India. The divide between formal and informal work, unpaid work, mainly being done by women, need to be investigated to ensure substantive gender parity. The findings will show that females are still not equal to men in employment, especially in senior private positions; mainly due to the remnants of patriarchy and glass ceilings that still need to be shattered. This article aims to set out the reasons why gender disparity still exists in India and South Africa, seen through a legal lense. Both countries are signatories to the CEDAW Convention and have constitutions that advocate for the right of equality. Although equal rights have been implemented in both countries, equality may not be well implemented. This investigation is comparative in nature and aims to contribute to the growing body of evidence on how to ensure gender parity in all occupational levels and categories. The study is in quantitative in nature. If substantive gender equality, as opposed to formative gender equality, is a key motivator to ensure gender equality, an investigation into the reasons for this disparity is warranted before suggestions can be tendered to effect lasting change. The aim of this comparative study is not to plug the legal system of one country into the other, but to take into account of the autonomy of choice, set against cultural differences and similarities in an effort to shatter the glass ceilings for women who aspire to climb the corporate ladders.Keywords: gender inequality, glass ceilings, patriarchy, female disparity
Procedia PDF Downloads 611078 CsPbBr₃@MOF-5-Based Single Drop Microextraction for in-situ Fluorescence Colorimetric Detection of Dechlorination Reaction
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
Procedia PDF Downloads 1381077 The Direct Deconvolution Model for the Large Eddy Simulation of Turbulence
Authors: Ning Chang, Zelong Yuan, Yunpeng Wang, Jianchun Wang
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Large eddy simulation (LES) has been extensively used in the investigation of turbulence. LES calculates the grid-resolved large-scale motions and leaves small scales modeled by sublfilterscale (SFS) models. Among the existing SFS models, the deconvolution model has been used successfully in the LES of the engineering flows and geophysical flows. Despite the wide application of deconvolution models, the effects of subfilter scale dynamics and filter anisotropy on the accuracy of SFS modeling have not been investigated in depth. The results of LES are highly sensitive to the selection of filters and the anisotropy of the grid, which has been overlooked in previous research. In the current study, two critical aspects of LES are investigated. Firstly, we analyze the influence of sub-filter scale (SFS) dynamics on the accuracy of direct deconvolution models (DDM) at varying filter-to-grid ratios (FGR) in isotropic turbulence. An array of invertible filters are employed, encompassing Gaussian, Helmholtz I and II, Butterworth, Chebyshev I and II, Cauchy, Pao, and rapidly decaying filters. The significance of FGR becomes evident, as it acts as a pivotal factor in error control for precise SFS stress prediction. When FGR is set to 1, the DDM models cannot accurately reconstruct the SFS stress due to the insufficient resolution of SFS dynamics. Notably, prediction capabilities are enhanced at an FGR of 2, resulting in accurate SFS stress reconstruction, except for cases involving Helmholtz I and II filters. A remarkable precision close to 100% is achieved at an FGR of 4 for all DDM models. Additionally, the further exploration extends to the filter anisotropy to address its impact on the SFS dynamics and LES accuracy. By employing dynamic Smagorinsky model (DSM), dynamic mixed model (DMM), and direct deconvolution model (DDM) with the anisotropic filter, aspect ratios (AR) ranging from 1 to 16 in LES filters are evaluated. The findings highlight the DDM's proficiency in accurately predicting SFS stresses under highly anisotropic filtering conditions. High correlation coefficients exceeding 90% are observed in the a priori study for the DDM's reconstructed SFS stresses, surpassing those of the DSM and DMM models. However, these correlations tend to decrease as lter anisotropy increases. In the a posteriori studies, the DDM model consistently outperforms the DSM and DMM models across various turbulence statistics, encompassing velocity spectra, probability density functions related to vorticity, SFS energy flux, velocity increments, strain-rate tensors, and SFS stress. It is observed that as filter anisotropy intensify, the results of DSM and DMM become worse, while the DDM continues to deliver satisfactory results across all filter-anisotropy scenarios. The findings emphasize the DDM framework's potential as a valuable tool for advancing the development of sophisticated SFS models for LES of turbulence.Keywords: deconvolution model, large eddy simulation, subfilter scale modeling, turbulence
Procedia PDF Downloads 681076 Characterization of Thin Woven Composites Used in Printed Circuit Boards by Combining Numerical and Experimental Approaches
Authors: Gautier Girard, Marion Martiny, Sebastien Mercier, Mohamad Jrad, Mohamed-Slim Bahi, Laurent Bodin, Francois Lechleiter, David Nevo, Sophie Dareys
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Reliability of electronic devices has always been of highest interest for Aero-MIL and space applications. In any electronic device, Printed Circuit Board (PCB), providing interconnection between components, is a key for reliability. During the last decades, PCB technologies evolved to sustain and/or fulfill increased original equipment manufacturers requirements and specifications, higher densities and better performances, faster time to market and longer lifetime, newer material and mixed buildups. From the very beginning of the PCB industry up to recently, qualification, experiments and trials, and errors were the most popular methods to assess system (PCB) reliability. Nowadays OEM, PCB manufacturers and scientists are working together in a close relationship in order to develop predictive models for PCB reliability and lifetime. To achieve that goal, it is fundamental to characterize precisely base materials (laminates, electrolytic copper, …), in order to understand failure mechanisms and simulate PCB aging under environmental constraints by means of finite element method for example. The laminates are woven composites and have thus an orthotropic behaviour. The in-plane properties can be measured by combining classical uniaxial testing and digital image correlation. Nevertheless, the out-of-plane properties cannot be evaluated due to the thickness of the laminate (a few hundred of microns). It has to be noted that the knowledge of the out-of-plane properties is fundamental to investigate the lifetime of high density printed circuit boards. A homogenization method combining analytical and numerical approaches has been developed in order to obtain the complete elastic orthotropic behaviour of a woven composite from its precise 3D internal structure and its experimentally measured in-plane elastic properties. Since the mechanical properties of the resin surrounding the fibres are unknown, an inverse method is proposed to estimate it. The methodology has been applied to one laminate used in hyperfrequency spatial applications in order to get its elastic orthotropic behaviour at different temperatures in the range [-55°C; +125°C]. Next; numerical simulations of a plated through hole in a double sided PCB are performed. Results show the major importance of the out-of-plane properties and the temperature dependency of these properties on the lifetime of a printed circuit board. Acknowledgements—The support of the French ANR agency through the Labcom program ANR-14-LAB7-0003-01, support of CNES, Thales Alenia Space and Cimulec is acknowledged.Keywords: homogenization, orthotropic behaviour, printed circuit board, woven composites
Procedia PDF Downloads 1961075 Acoustic Energy Harvesting Using Polyvinylidene Fluoride (PVDF) and PVDF-ZnO Piezoelectric Polymer
Authors: S. M. Giripunje, Mohit Kumar
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Acoustic energy that exists in our everyday life and environment have been overlooked as a green energy that can be extracted, generated, and consumed without any significant negative impact to the environment. The harvested energy can be used to enable new technology like wireless sensor networks. Technological developments in the realization of truly autonomous MEMS devices and energy storage systems have made acoustic energy harvesting (AEH) an increasingly viable technology. AEH is the process of converting high and continuous acoustic waves from the environment into electrical energy by using an acoustic transducer or resonator. AEH is not popular as other types of energy harvesting methods since sound waves have lower energy density and such energy can only be harvested in very noisy environment. However, the energy requirements for certain applications are also correspondingly low and also there is a necessity to observe the noise to reduce noise pollution. So the ability to reclaim acoustic energy and store it in a usable electrical form enables a novel means of supplying power to relatively low power devices. A quarter-wavelength straight-tube acoustic resonator as an acoustic energy harvester is introduced with polyvinylidene fluoride (PVDF) and PVDF doped with ZnO nanoparticles, piezoelectric cantilever beams placed inside the resonator. When the resonator is excited by an incident acoustic wave at its first acoustic eigen frequency, an amplified acoustic resonant standing wave is developed inside the resonator. The acoustic pressure gradient of the amplified standing wave then drives the vibration motion of the PVDF piezoelectric beams, generating electricity due to the direct piezoelectric effect. In order to maximize the amount of the harvested energy, each PVDF and PVDF-ZnO piezoelectric beam has been designed to have the same structural eigen frequency as the acoustic eigen frequency of the resonator. With a single PVDF beam placed inside the resonator, the harvested voltage and power become the maximum near the resonator tube open inlet where the largest acoustic pressure gradient vibrates the PVDF beam. As the beam is moved to the resonator tube closed end, the voltage and power gradually decrease due to the decreased acoustic pressure gradient. Multiple piezoelectric beams PVDF and PVDF-ZnO have been placed inside the resonator with two different configurations: the aligned and zigzag configurations. With the zigzag configuration which has the more open path for acoustic air particle motions, the significant increases in the harvested voltage and power have been observed. Due to the interruption of acoustic air particle motion caused by the beams, it is found that placing PVDF beams near the closed tube end is not beneficial. The total output voltage of the piezoelectric beams increases linearly as the incident sound pressure increases. This study therefore reveals that the proposed technique used to harvest sound wave energy has great potential of converting free energy into useful energy.Keywords: acoustic energy, acoustic resonator, energy harvester, eigenfrequency, polyvinylidene fluoride (PVDF)
Procedia PDF Downloads 3761074 Study of the Impact of Quality Management System on Chinese Baby Dairy Product Industries
Authors: Qingxin Chen, Liben Jiang, Andrew Smith, Karim Hadjri
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Since 2007, the Chinese food industry has undergone serious food contamination in the baby dairy industry, especially milk powder contamination. One of the milk powder products was found to contain melamine and a significant number (294,000) of babies were affected by kidney stones. Due to growing concerns among consumers about food safety and protection, and high pressure from central government, companies must take radical action to ensure food quality protection through the use of an appropriate quality management system. Previously, though researchers have investigated the health and safety aspects of food industries and products, quality issues concerning food products in China have been largely over-looked. Issues associated with baby dairy products and their quality issues have not been discussed in depth. This paper investigates the impact of quality management systems on the Chinese baby dairy product industry. A literature review was carried out to analyse the use of quality management systems within the Chinese milk power market. Moreover, quality concepts, relevant standards, laws, regulations and special issues (such as Melamine, Flavacin M1 contamination) have been analysed in detail. A qualitative research approach is employed, whereby preliminary analysis was conducted by interview, and data analysis based on interview responses from four selected Chinese baby dairy product companies was carried out. Through the analysis of literature review and data findings, it has been revealed that for quality management system that has been designed by many practitioners, many theories, models, conceptualisation, and systems are present. These standards and procedures should be followed in order to provide quality products to consumers, but the implementation is lacking in the Chinese baby dairy industry. Quality management systems have been applied by the selected companies but the implementation still needs improvement. For instance, the companies have to take measures to improve their processes and procedures with relevant standards. The government need to make more interventions and take a greater supervisory role in the production process. In general, this research presents implications for the regulatory bodies, Chinese Government and dairy food companies. There are food safety laws prevalent in China but they have not been widely practiced by companies. Regulatory bodies must take a greater role in ensuring compliance with laws and regulations. The Chinese government must also play a special role in urging companies to implement relevant quality control processes. The baby dairy companies not only have to accept the interventions from the regulatory bodies and government, they also need to ensure that production, storage, distribution and other processes will follow the relevant rules and standards.Keywords: baby dairy product, food quality, milk powder contamination, quality management system
Procedia PDF Downloads 4661073 Exploring Identity of Female British Pakistani Student with Shifting and Re-shifting of Cultures
Authors: Haleema Sadia
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The study is aimed at exploring the identity construction of female British born Pakistani postgraduate student who shifted to Pakistan at the age of 12, stayed there for 8 years and re-shifted to UK for Higher Education. Research questions are: 1. What is the academic and socio-cultural background of the participant prior to joining the UoM as a postgrad student? 2. How the participant talk, see herself and act in relation to cultural and social norms and practices? Participant’ identity is explored through positioning theory of Holland et al. (1998), referring to the ways people understand and enact their social positions in the figured world. The research is a case study based on narrative interview of Shabana, a British-born Pakistani female postgraduate student, who has recently joined the university of Manchester. Shabana received her primary education in UK during the first twelve years of her life. She is the youngest among the three sisters, with only one brother younger to her. Her father, although not well educated is a successful entrepreneur, maintaining offices in UK and Pakistan. Her mother is a housewife with no formal education. Shabana’s elder sister got involved in a relationship with a Pakistani boy against cultural norms of arranged marriage. Resultantly the three sisters were shifted to Pakistan to be equated with socio-religious norms. Shabana termed her first year in Pakistan as disgusting and she hated her father for the decision. However after a year’s time and shifting from an orthodox city to the provincial capital Lahore, she developed liking for the Pakistani culture. She gradually developed a new socio-religious identity during her stay, which she expressed as a turning point in her life. After completing O level Shabana returned back to UK and joined the University of Hull as undergraduate Student. At Hull she remained isolated, missed the religious environment and relished the memories of Lahore. She would visit Pakistan almost three times a year. After obtaining her BSc degree from Hull she went back to Pakistan. Soon after she decided to improve her academic qualification. She came to UK to join her parents and got admission in the MSc chemistry program at UoM. Presently Shabana talks about the dominant role of male members in the family culture in decision-making. She strongly feels to struggle hard and attain equal status with males in education, employment, earning, authority and freedom. She sees herself in a position to share the authority with her (would be) husband in important family and other matters. Shabana has developed a new identity of a mix of both Pakistani and UK culture. She is appreciative of the socio-cultural values of UK while still regarding the cultural and religious values of Pakistan in high esteem.Keywords: postgraduate students, identity construction, cultural shifts, female british pakistani student
Procedia PDF Downloads 6171072 Persistent Ribosomal In-Frame Mis-Translation of Stop Codons as Amino Acids in Multiple Open Reading Frames of a Human Long Non-Coding RNA
Authors: Leonard Lipovich, Pattaraporn Thepsuwan, Anton-Scott Goustin, Juan Cai, Donghong Ju, James B. Brown
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Two-thirds of human genes do not encode any known proteins. Aside from long non-coding RNA (lncRNA) genes with recently-discovered functions, the ~40,000 non-protein-coding human genes remain poorly understood, and a role for their transcripts as de-facto unconventional messenger RNAs has not been formally excluded. Ribosome profiling (Riboseq) predicts translational potential, but without independent evidence of proteins from lncRNA open reading frames (ORFs), ribosome binding of lncRNAs does not prove translation. Previously, we mass-spectrometrically documented translation of specific lncRNAs in human K562 and GM12878 cells. We now examined lncRNA translation in human MCF7 cells, integrating strand-specific Illumina RNAseq, Riboseq, and deep mass spectrometry in biological quadruplicates performed at two core facilities (BGI, China; City of Hope, USA). We excluded known-protein matches. UCSC Genome Browser-assisted manual annotation of imperfect (tryptic-digest-peptides)-to-(lncRNA-three-frame-translations) alignments revealed three peptides hypothetically explicable by 'stop-to-nonstop' in-frame replacement of stop codons by amino acids in two ORFs of the lncRNA MMP24-AS1. To search for this phenomenon genomewide, we designed and implemented a novel pipeline, matching tryptic-digest spectra to wildcard-instead-of-stop versions of repeat-masked, six-frame, whole-genome translations. Along with singleton putative stop-to-nonstop events affecting four other lncRNAs, we identified 24 additional peptides with stop-to-nonstop in-frame substitutions from multiple positive-strand MMP24-AS1 ORFs. Only UAG and UGA, never UAA, stop codons were impacted. All MMP24-AS1-matching spectra met the same significance thresholds as high-confidence known-protein signatures. Targeted resequencing of MMP24-AS1 genomic DNA and cDNA from the same samples did not reveal any mutations, polymorphisms, or sequencing-detectable RNA editing. This unprecedented apparent gene-specific violation of the genetic code highlights the importance of matching peptides to whole-genome, not known-genes-only, ORFs in mass-spectrometry workflows, and suggests a new mechanism enhancing the combinatorial complexity of the proteome. Funding: NIH Director’s New Innovator Award 1DP2-CA196375 to LL.Keywords: genetic code, lncRNA, long non-coding RNA, mass spectrometry, proteogenomics, ribo-seq, ribosome, RNAseq
Procedia PDF Downloads 2241071 Health Literacy: Collaboration between Clinician and Patient
Authors: Cathy Basterfield
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Issue: To engage in one’s own health care, health professionals need to be aware of an individual’s specific skills and abilities for best communication. One of the most discussed is health literacy. One of the assumed skills and abilities for adults is an individuals’ health literacy. Background: A review of publicly available health content appears to assume all adult readers will have a broad and full capacity to read at a high level of literacy, often at a post-school education level. Health information writers and clinicians need to recognise one critical area for why there may be little or no change in a person’s behaviour, or no-shows to appointments. Perhaps unintentionally, they are miscommunicating with the majority of the adult population. Health information contains many literacy domains. It usually includes technical medical terms or jargon. Many fact sheets and other information require scientific literacy with or without specific numerical literacy. It may include graphs, percentages, timing, distance, or weights. Each additional word or concept in these domains decreases the readers' ability to meaningfully read, understand and know what to do with the information. An attempt to begin to read the heading where long or unfamiliar words are used will reduce the readers' motivation to attempt to read. Critically people who have low literacy are overwhelmed when pages are covered with lots of words. People attending a health environment may be unwell or anxious about a diagnosis. These make it harder to read, understand and know what to do with the information. But access to health information must consider an even wider range of adults, including those with poor school attainment, migrants, and refugees. It is also homeless people, people with mental health illnesses, or people who are ageing. People with low literacy also may include people with lifelong disabilities, people with acquired disabilities, people who read English as a second (or third) language, people who are Deaf, or people who are vision impaired. Outcome: This paper will discuss Easy English, which is developed for adults. It uses the audiences’ everyday words, short sentences, short words, and no jargon. It uses concrete language and concrete, specific images to support the text. It has been developed in Australia since the mid-2000s. This paper will showcase various projects in the health domain which use Easy English to improve the understanding and functional use of written information for the large numbers of adults in our communities who do not have the health literacy to manage a range of day to day reading tasks. See examples from consent forms, fact sheets and choice options, instructions, and other functional documents, where Easy English has been developed. This paper will ask individuals to reflect on their own work practice and consider what written information must be available in Easy English. It does not matter how cutting-edge a new treatment is; when adults can not read or understand what it is about and the positive and negative outcomes, they are less likely to be engaged in their own health journey.Keywords: health literacy, inclusion, Easy English, communication
Procedia PDF Downloads 1171070 Exploring the Success of Live Streaming Commerce in China: A Literature Analysis
Authors: Ming Gao, Matthew Tingchi Liu, Hoi Ngan Loi
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Live streaming refers to the video contents generated by broadcasters and shared with viewers in real-time by uploading them to short-video platforms. In recent years, individual KOL broadcasters have successfully made use of live streams to sell a large amount of goods to the consumers. For example, Wei Ya, the Number 1 broadcaster in Taobao Live, sold products worth RMB 2.7 billion (USD 0.38 billion) in 2018. Regarding the success of live streaming commerce (LSC) in China, this study explores the elements of the booming LSC industry and attempts to explain the reasons behind its prosperity. A systematic review of industry reports and academic papers was conducted to summarize the latest findings in this field. And the results of this investigation showed that a live streaming eco-system has been established by the LSC players, namely, the platform, the broadcaster, the product supplier, and the viewer. In this eco-system, all players have complementary advantages and needs, and their close cooperation leads to a win-win situation. For instance, platforms and broadcasters have abundant internet traffic, which needs to be monetized, while product suppliers have mature supply chains and the need of promoting the products. In addition, viewers are attached to the LSC platforms to get product information, bargains, and entertainment. This study highlights the importance of the mass-personal hybrid communication nature of live streaming because its interpersonal communication feature increases consumers’ positive experiences, while its mass media broadcasting feature facilitates product promotion. Another innovative point of this study lies in its inclusion of the special characteristic of Chinese Internet culture - entertainment. The entertaining genres of the live streams created by broadcasters serve as down-to-earth approaches to reach their audiences easily. Further, the nature of video, i.e., the dynamic and salient stimulus, is emphasized in this study. Since video is more engaging, it can attract viewers in a quick and easy way. Meanwhile, the abundant, interesting, high-quality, and free short videos have added “stickiness” to platforms by retaining users and prolonging their staying time on the platforms. In addition, broadcasters’ important characters, such as physical attractiveness, humor, sex appeal, kindness, communication skills, and interactivity, are also identified as important factors that influence consumers’ engagement and purchase intention. In conclusion, all players have their own proper places in this live streaming eco-system, in which they work seamlessly to give full play to their respective advantages, with each player taking what it needs and offering what it has. This has contributed to the success of live streaming commerce in China.Keywords: broadcasters, communication, entertainment, live streaming commerce, viewers
Procedia PDF Downloads 1161069 Study of Chemical State Analysis of Rubidium Compounds in Lα, Lβ₁, Lβ₃,₄ and Lγ₂,₃ X-Ray Emission Lines with Wavelength Dispersive X-Ray Fluorescence Spectrometer
Authors: Harpreet Singh Kainth
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Rubidium salts have been commonly used as an electrolyte to improve the efficiency cycle of Li-ion batteries. In recent years, it has been implemented into the large scale for further technological advances to improve the performance rate and better cyclability in the batteries. X-ray absorption spectroscopy (XAS) is a powerful tool for obtaining the information in the electronic structure which involves the chemical state analysis in the active materials used in the batteries. However, this technique is not well suited for the industrial applications because it needs a synchrotron X-ray source and special sample file for in-situ measurements. In contrast to this, conventional wavelength dispersive X-ray fluorescence (WDXRF) spectrometer is nondestructive technique used to study the chemical shift in all transitions (K, L, M, …) and does not require any special pre-preparation planning. In the present work, the fluorescent Lα, Lβ₁ , Lβ₃,₄ and Lγ₂,₃ X-ray spectra of rubidium in different chemical forms (Rb₂CO₃ , RbCl, RbBr, and RbI) have been measured first time with high resolution wavelength dispersive X-ray fluorescence (WDXRF) spectrometer (Model: S8 TIGER, Bruker, Germany), equipped with an Rh anode X-ray tube (4-kW, 60 kV and 170 mA). In ₃₇Rb compounds, the measured energy shifts are in the range (-0.45 to - 1.71) eV for Lα X-ray peak, (0.02 to 0.21) eV for Lβ₁ , (0.04 to 0.21) eV for Lβ₃ , (0.15 to 0.43) eV for Lβ₄ and (0.22 to 0.75) eV for Lγ₂,₃ X-ray emission lines. The chemical shifts in rubidium compounds have been measured by considering Rb₂CO₃ compounds taking as a standard reference. A Voigt function is used to determine the central peak position of all compounds. Both positive and negative shifts have been observed in L shell emission lines. In Lα X-ray emission lines, all compounds show negative shift while in Lβ₁, Lβ₃,₄, and Lγ₂,₃ X-ray emission lines, all compounds show a positive shift. These positive and negative shifts result increase or decrease in X-ray energy shifts. It looks like that ligands attached with central metal atom attract or repel the electrons towards or away from the parent nucleus. This pulling and pushing character of rubidium affects the central peak position of the compounds which causes a chemical shift. To understand the chemical effect more briefly, factors like electro-negativity, line intensity ratio, effective charge and bond length are responsible for the chemical state analysis in rubidium compounds. The effective charge has been calculated from Suchet and Pauling method while the line intensity ratio has been calculated by calculating the area under the relevant emission peak. In the present work, it has been observed that electro-negativity, effective charge and intensity ratio (Lβ₁/Lα, Lβ₃,₄/Lα and Lγ₂,₃/Lα) are inversely proportional to the chemical shift (RbCl > RbBr > RbI), while bond length has been found directly proportional to the chemical shift (RbI > RbBr > RbCl).Keywords: chemical shift in L emission lines, bond length, electro-negativity, effective charge, intensity ratio, Rubidium compounds, WDXRF spectrometer
Procedia PDF Downloads 5001068 Density Functional Theory Study of the Surface Interactions between Sodium Carbonate Aerosols and Fission Products
Authors: Ankita Jadon, Sidi Souvi, Nathalie Girault, Denis Petitprez
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The interaction of fission products (FP) with sodium carbonate (Na₂CO₃) aerosols is of a high safety concern because of their potential role in the radiological source term mitigation by FP trapping. In a sodium-cooled fast nuclear reactor (SFR) experiencing a severe accident, sodium (Na) aerosols can be formed after the ejection of the liquid Na coolant inside the containment. The surface interactions between these aerosols and different FP species have been investigated using ab-initio, density functional theory (DFT) calculations using Vienna ab-initio simulation package (VASP). In addition, an improved thermodynamic model has been proposed to treat DFT-VASP calculated energies to extrapolate them to temperatures and pressures of interest in our study. A combined experimental and theoretical chemistry study has been carried out to have both atomistic and macroscopic understanding of the chemical processes; the theoretical chemistry part of this approach is presented in this paper. The Perdew, Burke, and Ernzerhof functional were applied in combination with Grimme’s van der Waals correction to compute exchange-correlational energy at 0 K. Seven different surface cleavages were studied of Ƴ-Na₂CO₃ phase (stable at 603.15 K), it was found that for defect-free surfaces, the (001) facet is the most stable. Furthermore, calculations were performed to study surface defects and reconstructions on the ideal surface. All the studied surface defects were found to be less stable than the ideal surface. More than one adsorbate-ligand configurations were found to be stable confirming that FP vapors could be trapped on various adsorption sites. The calculated adsorption energies (Eads, eV) for the three most stable adsorption sites for I₂ are -1.33, -1.088, and -1.085. Moreover, the adsorption of the first molecule of I₂ changes the surface in a way which would favor stronger adsorption of a second molecule of I2 (Eads, eV = -1.261). For HI adsorption, the most favored reactions have the following Eads (eV) -1.982, -1.790, -1.683 implying that HI would be more reactive than I₂. In addition to FP species, adsorption of H₂O was also studied as the hydrated surface can have different reactivity than the bare surface. One thermodynamically favored site for H₂O adsorption was found with an Eads, eV of -0.754. Finally, the calculations of hydrated surfaces of Na₂CO₃ show that a layer of water adsorbed on the surface significantly reduces its affinity for iodine (Eads, eV = -1.066). According to the thermodynamic model built, the required partial pressure at 373 K to have adsorption of the first layer of iodine is 4.57×10⁻⁴ bar. The second layer will be adsorbed at partial pressures higher than 8.56×10⁻⁶ bar; a layer of water on the surface will increase these pressure almost ten folds to 3.71×10⁻³ bar. The surface interacts with elemental Cs with an Eads (eV) of -1.60, while interacts even strongly with CsI with an Eads (eV) of -2.39. More results on the interactions between Na₂CO₃ (001) and cesium-based FP will also be presented in this paper.Keywords: iodine uptake, sodium carbonate surface, sodium-cooled fast nuclear reactor, DFT calculations, fission products
Procedia PDF Downloads 1461067 Evaluation of the Effectiveness of Crisis Management Support Bases in Tehran
Authors: Sima Hajiazizi
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Tehran is a capital of Iran, with the capitals of the world to natural disasters such as earthquake and flood vulnerable has known. City has stated on three faults, Ray, Mosha, and north according to report of JICA in 2000, the most casualties and destruction was the result of active fault Ray. In 2003, the prevention and management of crisis in Tehran to conduct prevention and rehabilitation of the city, under the Ministry has active. Given the breadth and lack of appropriate access in the city, was considered decentralized management for crisis management support, in each region, in order to position the crisis management headquarters at the time of crises and implementation of programs for prevention and education of the citizens and also to position the bases given in some areas of the neighboring provinces at the time of the accident for help and a number of databases to store food and equipment needed at the time of the disaster. In this study, the bases for one, six, nine and eleven regions of Tehran in the field of management and training are evaluated. Selected areas had local accident and experience of practice for disaster management and local training has been experiencing challenges. The research approach was used qualitative research methods underlying Ground theory. At first, the information obtained through the study of documents and Semi-structured interviews by administrators, officials of training and participant observation in the classroom, line by line, and then it was coded in two stages, by comparing and questioning concepts, categories and extract according to the indicators is obtained from literature studies, subjects were been central. Main articles according to the frequency and importance of the phenomenon were called and they were drawn diagram paradigm and at the end with the intersections phenomena and their causes with indicators extracted from the texts, approach each phenomenon and the effectiveness of the bases was measured. There are two phenomenons in management; 1. The inability to manage the vast and complex crisis events and to resolve minor incidents due to the mismatch between managers. 2. Weaknesses in the implementation of preventive measures and preparedness to manage crisis is causal of situations, fields and intervening. There are five phenomenons in the field of education; 1. In the six-region participation and interest is high. 2. In eleven-region training partnerships for crisis management were to low that next by maneuver in schools and local initiatives such as advertising and use of aid groups have increased. 3. In nine-region, contributions to education in the area of crisis management at the beginning were low that initiatives like maneuver in schools and communities to stimulate and increase participation have increased sensitivity. 4. Managers have been disagreement with the same training in all areas. Finally for the issues that are causing the main issues, with the help of concepts extracted from the literature, recommendations are provided.Keywords: crises management, crisis management support bases, vulnerability, crisis management headquarters, prevention
Procedia PDF Downloads 1681066 Early Childhood Education for Bilingual Children: A Cross-Cultural Examination
Authors: Dina C. Castro, Rossana Boyd, Eugenia Papadaki
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Immigration within and across continents is currently a global reality. The number of people leaving their communities in search for a better life for them and their families has increased dramatically during the last twenty years. Therefore, young children of the 21st century around the World are growing up in diverse communities, exposed to many languages and cultures. One consequence of these migration movements is the increased linguistic diversity in school settings. Depending on the linguistic history and the status of languages in the communities (i.e., minority-majority; majority-majority) the instructional approaches will differ. This session will discuss how bilingualism is addressed in early education programs in both minority-majority and majority-majority language communities, analyzing experiences in three countries with very distinct societal and demographic characteristics: Peru (South America), the United States (North America), and Italy (European Union). The ultimate goal is to identify commonalities and differences across the three experiences that could lead to a discussion of bilingualism in early education from a global perspective. From Peru, we will discuss current national language and educational policies that have lead to the design and implementation of bilingual and intercultural education for children in indigenous communities. We will also discuss how those practices are being implemented in preschool programs, the progress made and challenges encountered. From the United States, we will discuss the early education of Spanish-English bilingual preschoolers, including the national policy environment, as well as variations in language of instruction approaches currently being used with these children. From Italy, we will describe early education practices in the Bilingual School of Monza, in northern Italy, a school that has 20 years promoting bilingualism and multilingualism in education. While the presentations from Peru and the United States will discuss bilingualism in a majority-minority language environment, this presentation will lead to a discussion on the opportunities and challenges of promoting bilingualism in a majority-majority language environment. It is evident that innovative models and policies are necessary to prevent inequality of opportunities for bilingual children beginning in their earliest years. The cross-cultural examination of bilingual education experiences for young children in three part of the World will allow us to learn from our success and challenges. The session will end with a discussion of the following question: To what extent are early care and education programs being effective in promoting positive development and learning among all children, including those from diverse language, ethnic and cultural backgrounds? We expect to identify, with participants to our session, a set of recommendations for policy and program development that could ensure access to high quality early education for all bilingual children.Keywords: early education for bilingual children, global perspectives in early education, cross-cultural, language policies
Procedia PDF Downloads 2941065 Robotics Education Continuity from Diaper Age to Doctorate
Authors: Vesa Salminen, Esa Santakallio, Heikki Ruohomaa
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Introduction: The city of Riihimäki has decided robotics on well-being, service and industry as the main focus area on their ecosystem strategy. Robotics is going to be an important part of the everyday life of citizens and present in the working day of the average citizen and employee in the future. For that reason, also education system and education programs on all levels of education from diaper age to doctorate have been directed to fulfill this ecosystem strategy. Goal: The objective of this activity has been to develop education continuity from diaper age to doctorate. The main target of the development activity is to create a unique robotics study entity that enables ongoing robotics studies from preprimary education to university. The aim is also to attract students internationally and supply a skilled workforce to the private sector, capable of the challenges of the future. Methodology: Education instances (high school, second grade, Universities on all levels) in a large area of Tavastia Province have gradually directed their education programs to support this goal. On the other hand, applied research projects have been created to make proof of concept- phases on areal real environment field labs to test technology opportunities and digitalization to change business processes by applying robotic solutions. Customer-oriented applied research projects offer for students in robotics education learning environments to learn new knowledge and content. That is also a learning environment for education programs to adapt and co-evolution. New content and problem-based learning are used in future education modules. Major findings: Joint robotics education entity is being developed in cooperation with the city of Riihimäki (primary education), Syria Education (secondary education) and HAMK (bachelor and master education). The education modules have been developed to enable smooth transitioning from one institute to another. This article is introduced a case study of the change of education of wellbeing education because of digitalization and robotics. Riihimäki's Elderly citizen's service house, Riihikoti, has been working as a field lab for proof-of-concept phases on testing technology opportunities. According to successful case studies also education programs on various levels of education have been changing. Riihikoti has been developed as a physical learning environment for home care and robotics, investigating and developing a variety of digital devices and service opportunities and experimenting and learn the use of equipment. The environment enables the co-development of digital service capabilities in the authentic environment for all interested groups in transdisciplinary cooperation.Keywords: ecosystem strategy, digitalization and robotics, education continuity, learning environment, transdisciplinary co-operation
Procedia PDF Downloads 1711064 Freshwater Pinch Analysis for Optimal Design of the Photovoltaic Powered-Pumping System
Authors: Iman Janghorban Esfahani
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Due to the increased use of irrigation in agriculture, the importance and need for highly reliable water pumping systems have significantly increased. The pumping of the groundwater is essential to provide water for both drip and furrow irrigation to increase the agricultural yield, especially in arid regions that suffer from scarcities of surface water. The most common irrigation pumping systems (IPS) consume conventional energies through the use of electric motors and generators or connecting to the electricity grid. Due to the shortage and transportation difficulties of fossil fuels, and unreliable access to the electricity grid, especially in the rural areas, and the adverse environmental impacts of fossil fuel usage, such as greenhouse gas (GHG) emissions, the need for renewable energy sources such as photovoltaic systems (PVS) as an alternative way of powering irrigation pumping systems is urgent. Integration of the photovoltaic systems with irrigation pumping systems as the Photovoltaic Powered-Irrigation Pumping System (PVP-IPS) can avoid fossil fuel dependency and the subsequent greenhouse gas emissions, as well as ultimately lower energy costs and improve efficiency, which made PVP-IPS systems as an environmentally and economically efficient solution for agriculture irrigation in every region. The greatest problem faced by integration of PVP with IPS systems is matching the intermittence of the energy supply with the dynamic water demand. The best solution to overcome the intermittence is to incorporate a storage system into the PVP-IPS to provide water-on-demand as a highly reliable stand-alone irrigation pumping system. The water storage tank (WST) is the most common storage device for PVP-IPS systems. In the integrated PVP-IPS with a water storage tank (PVP-IPS-WST), a water storage tank stores the water pumped by the IPS in excess of the water demand and then delivers it when demands are high. The Freshwater pinch analysis (FWaPA) as an alternative to mathematical modeling was used by other researchers for retrofitting the off-grid battery less photovoltaic-powered reverse osmosis system. However, the Freshwater pinch analysis has not been used to integrate the photovoltaic systems with irrigation pumping system with water storage tanks. In this study, FWaPA graphical and numerical tools were used for retrofitting an existing PVP-IPS system located in Salahadin, Republic of Iraq. The plant includes a 5 kW submersible water pump and 7.5 kW solar PV system. The Freshwater Composite Curve as the graphical tool and Freashwater Storage Cascade Table as the numerical tool were constructed to determine the minimum required outsourced water during operation, optimal amount of delivered electricity to the water pump, and optimal size of the water storage tank for one-year operation data. The results of implementing the FWaPA on the case study show that the PVP-IPS system with a WST as the reliable system can reduce outsourced water by 95.41% compare to the PVP-IPS system without storage tank.Keywords: irrigation, photovoltaic, pinch analysis, pumping, solar energy
Procedia PDF Downloads 1341063 Inhibition of the Activity of Polyphenol Oxidase Enzyme Present in Annona muricata and Musa acuminata by the Experimentally Identified Natural Anti-Browning Agents
Authors: Michelle Belinda S. Weerawardana, Gobika Thiripuranathar, Priyani A. Paranagama
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Most of fresh vegetables and fruits available in the retail markets undergo a physiological disorder in its appearance and coloration, which indeed discourages consumer purchase. A loss of millions of dollars yearly to the food industry had been due to this pronounced color reaction called Enzymatic Browning which is driven due to the catalytic activity by an oxidoreductase enzyme, polyphenol oxidase (PPO). The enzyme oxidizes the phenolic compounds which are abundantly available in fruits and vegetables as substrates into quinones, which could react with proteins in its surrounding to generate black pigments, called melanins, which are highly UV-active compounds. Annona muricata (Katu anoda) and Musa acuminata (Ash plantains) is a fruit and a vegetable consumed by Sri Lankans widely due to their high nutritional values, medicinal properties and economical importance. The objective of the present study was to evaluate and determine the effective natural anti-browning inhibitors that could prevent PPO activity in the selected fruit and vegetable. Enzyme extracts from Annona muricata (Katu anoda) and Musa acuminata (Ash plantains), were prepared by homogenizing with analytical grade acetone, and pH of each enzyme extract was maintained at 7.0 using a phosphate buffer. The extracts of inhibitors were prepared using powdered ginger rhizomes and essential oil from the bark of Cinnamomum zeylanicum. Water extracts of ginger were prepared and the essential oil from Ceylon cinnamon bark was extracted using steam distillation method. Since the essential oil is not soluble in water, 0.1µl of cinnamon bark oil was mixed with 0.1µl of Triton X-100 emulsifier and 5.00 ml of water. The effect of each inhibitor on the PPO activity was investigated using catechol (0.1 mol dm-3) as the substrate and two samples of enzyme extracts prepared. The dosages of the prepared Cinnamon bark oil, and ginger (2 samples) which were used to measure the activity were 0.0035 g/ml, 0.091 g/ml and 0.087 g/ml respectively. The measurements of the inhibitory activity were obtained at a wavelength of 525 nm using the UV-visible spectrophotometer. The results evaluated thus revealed that % inhibition observed with cinnamon bark oil, and ginger for Annona muricata was 51.97%, and 60.90% respectively. The effects of cinnamon bark oil, and ginger extract on PPO activity of Musa acuminata were 49.51%, and 48.10%. The experimental findings thus revealed that Cinnamomum zeylanicum bark oil was a more effective inhibitor for PPO enzyme present in Musa acuminata and ginger was effective for PPO enzyme present in Annona muricata. Overall both the inhibitors were proven to be more effective towards the activities of PPO enzyme present in both samples. These inhibitors can thus be corroborated as effective, natural, non-toxic, anti-browning extracts, which when added to the above fruit and vegetable will increase the shelf life and also the acceptance of the product by the consumers.Keywords: anti-browning agent, enzymatic browning, inhibitory activity, polyphenol oxidase
Procedia PDF Downloads 2691062 Application of Acoustic Emissions Related to Drought Can Elicit Antioxidant Responses and Capsaicinoids Content in Chili Pepper Plants
Authors: Laura Helena Caicedo Lopez, Luis Miguel Contreras Medina, Ramon Gerardo Guevara Gonzales, Juan E. Andrade
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In this study, we evaluated the effect of three different hydric stress conditions: Low (LHS), medium (MHS), and high (HHS) on capsaicinoid content and enzyme regulation of C. annuum plants. Five main peaks were detected using a 2 Hz resolution vibrometer laser (Polytec-B&K). These peaks or “characteristic frequencies” were used as acoustic emissions (AEs) treatment, transforming these signals into audible sound with the frequency (Hz) content of each hydric stress. Capsaicinoids (CAPs) are the main, secondary metabolites of chili pepper plants and are known to increase during hydric stress conditions or short drought-periods. The AEs treatments were applied in two plant stages: the first one was in the pre-anthesis stage to evaluate the genes that encode the transcription of enzymes responsible for diverse metabolic activities of C. annuum plants. For example, the antioxidant responses such as peroxidase (POD), superoxide dismutase (Mn-SOD). Also, phenyl-alanine ammonia-lyase (PAL) involved in the biosynthesis of the phenylpropanoid compounds. The chalcone synthase (CHS) related to the natural defense mechanisms and species-specific aquaporin (CAPIP-1) that regulate the flow of water into and out of cells. The second stage was at 40 days after flowering (DAF) to evaluate the biochemical effect of AEs related to hydric stress on capsaicinoids production. These two experiments were conducted to identify the molecular responses of C. annuum plants to AE. Moreover, to define AEs could elicit any increase in the capsaicinoids content after a one-week exposition to AEs treatments. The results show that all AEs treatment signals (LHS, MHS, and HHS) were significantly different compared to the non-acoustic emission control (NAE). Also, the AEs induced the up-regulation of POD (~2.8, 2.9, and 3.6, respectively). The gene expression of another antioxidant response was particularly treatment-dependent. The HHS induced and overexpression of Mn-SOD (~0.23) and PAL (~0.33). As well, the MHS only induced an up-regulation of the CHs gene (~0.63). On the other hand, CAPIP-1 gene gas down-regulated by all AEs treatments LHS, MHS, and HHS ~ (-2.4, -0.43 and -6.4, respectively). Likewise, the down-regulation showed particularities depending on the treatment. LHS and MHS induced downregulation of the SOD gene ~ (-1.26 and -1.20 respectively) and PAL (-4.36 and 2.05, respectively). Correspondingly, the LHS and HHS showed the same tendency in the CHs gene, respectively ~ (-1.12 and -1.02, respectively). Regarding the elicitation effect of AE on the capsaicinoids content, additional treatment controls were included. A white noise treatment (WN) to prove the frequency-selectiveness of signals and a hydric stressed group (HS) to compare the CAPs content. Our findings suggest that WN and NAE did not present differences statically. Conversely, HS and all AEs treatments induced a significant increase of capsaicin (Cap) and dihydrocapsaicin (Dcap) after one-week of a treatment. Specifically, the HS plants showed an increase of 8.33 times compared to the NAE and WN treatments and 1.4 times higher than the MHS, which was the AEs treatment with a larger induction of Capsaicinoids among treatments (5.88) and compared to the controls.Keywords: acoustic emission, capsaicinoids, elicitors, hydric stress, plant signaling
Procedia PDF Downloads 1631061 Pre-Cooling Strategies for the Refueling of Hydrogen Cylinders in Vehicular Transport
Authors: C. Hall, J. Ramos, V. Ramasamy
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Hydrocarbon-based fuel vehicles are a major contributor to air pollution due to harmful emissions produced, leading to a demand for cleaner fuel types. A leader in this pursuit is hydrogen, with its application in vehicles producing zero harmful emissions and the only by-product being water. To compete with the performance of conventional vehicles, hydrogen gas must be stored on-board of vehicles in cylinders at high pressures (35–70 MPa) and have a short refueling duration (approximately 3 mins). However, the fast-filling of hydrogen cylinders causes a significant rise in temperature due to the combination of the negative Joule-Thompson effect and the compression of the gas. This can lead to structural failure and therefore, a maximum allowable internal temperature of 85°C has been imposed by the International Standards Organization. The technological solution to tackle the issue of rapid temperature rise during the refueling process is to decrease the temperature of the gas entering the cylinder. Pre-cooling of the gas uses a heat exchanger and requires energy for its operation. Thus, it is imperative to determine the least amount of energy input that is required to lower the gas temperature for cost savings. A validated universal thermodynamic model is used to identify an energy-efficient pre-cooling strategy. The model requires negligible computational time and is applied to previously validated experimental cases to optimize pre-cooling requirements. The pre-cooling characteristics include the location within the refueling timeline and its duration. A constant pressure-ramp rate is imposed to eliminate the effects of rapid changes in mass flow rate. A pre-cooled gas temperature of -40°C is applied, which is the lowest allowable temperature. The heat exchanger is assumed to be ideal with no energy losses. The refueling of the cylinders is modeled with the pre-cooling split in ten percent time intervals. Furthermore, varying burst durations are applied in both the early and late stages of the refueling procedure. The model shows that pre-cooling in the later stages of the refuelling process is more energy-efficient than early pre-cooling. In addition, the efficiency of pre-cooling towards the end of the refueling process is independent of the pressure profile at the inlet. This leads to the hypothesis that pre-cooled gas should be applied as late as possible in the refueling timeline and at very low temperatures. The model had shown a 31% reduction in energy demand whilst achieving the same final gas temperature for a refueling scenario when pre-cooling was applied towards the end of the process. The identification of the most energy-efficient refueling approaches whilst adhering to the safety guidelines is imperative to reducing the operating cost of hydrogen refueling stations. Heat exchangers are energy-intensive and thus, reducing the energy requirement would lead to cost reduction. This investigation shows that pre-cooling should be applied as late as possible and for short durations.Keywords: cylinder, hydrogen, pre-cooling, refueling, thermodynamic model
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