Search results for: temperature analyses

Authors: Betina Luiza Koop, Lenilton Santos Soares, Karina Cesca, Germán Ayala Valencia, Alcilene Rodrigues Monteiro

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Active and smart food packaging has been studied to control and extend the food shelf-life. However, active compounds such as anthocyanins (ACNs) are unstable to high temperature, light, and pH changes. Several alternatives to stabilize and protect the anthocyanins have been researched, such as adsorption on nanoclays. Thus, this work aimed to stabilize anthocyanin extracted from jambolan fruit (Syzygium cumini), a noncommercial fruit, to development of food package sensors. The anthocyanin extract from jambolan pulp was concentrated by ultrafiltration and adsorbed on montmorillonite. The final biohybrid material was characterized by pH and color. Anthocyanins were adsorbed on nanoclay at pH 1.5, 2.5, and 3.5 and temperatures of 10 and 20 °C. The highest adsorption values were obtained at low pH at high temperatures. The color and antioxidant activity of the biohybrid was maintained for 60 days. A test of the color stability at pH from 1 to 13, simulating spoiled food using ammonia vapor, was performed. At pH from 1 to 5, the ACNs pink color was maintained, indicating that the flavylium cation form was preserved. At pH 13, the biohybrid presented yellow color due to the ACN oxidation. These results showed that the biohybrid material developed has potential application as a sensor to indicate the freshness of meat products.

Keywords: anthocyanin, biohybrid, food, smart packaging

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Authors: Feng-Tsai Weng, Rick Wang, Yan-Cong Liao

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Passivation is a kind of surface treatment for material to reinforce the corrosion resistance specially the stainless alloy. Passive film, is to getting more potential compared to their status before passivation. An oxidation film can be formed on the surface of stainless steel, which has a strong corrosion resistance ability after passivation treatment. In this research, a new passivation technology is proposed for a special stainless alloy which contains a 12-14% Chromium. This method includes the A-A-A (alkaline-acid-alkaline) process basically, which was developed by Carpenter that can neutralize trapped acid. Besides, a corrosion resistant coating layer was obtained by immersing the parts in a water bath of mineral oil at high temperature. Salt spray test ASTM B368 was conducted to investigated performance of corrosion resistant of the passivated stainless steel alloy parts. Results show much better corrosion resistant that followed a coating process after A-A-A Passivation process, than only using A-A-A process. The passivation time is with more than 380 hours of salt spray test ASTM B368, which is equal to 3000 hours of Salt spray test ASTM B117. Proposed passivation method of stainless steel can be completed in about 3 hours.

Keywords: passivation, alkaline-acid-alkaline, stainless steel, salt spray test

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Authors: Dandi Riswanto, Mahendra Wahyu Eka Pradana, Hutomo Abdurrohman

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The dairy farm has strategic roles in meeting the demand of foods. Sleman Regency is a central dairy production in Daerah Istimewa Yogyakarta. Sleman district has a population of 3954 heads dairy cattle with an environmental temperature of 22 to 35 degrees Celsius and humidity 74 to 87% which makes a good location for a dairy cattle farm. The dairy cattle that are kept by the majority of the Friesian Holstein Crossbreed are predominantly reared by conventional management. Sleman Regency accounts for 7.3% of national milk production. Factors influencing include genetic, environmental, and management. The purpose of this research was to determine the effect of Good Dairy Farming Practices (GDFP) application on milk production in Sleman Regency. The data collection was conducted in January 2017 until May 2017 using survey and interviews methods at 5 locations of dairy farms selected randomly. Data were analyzed with the chi-square test. The result of this research showed that GDFP point was management 1,47 points (less good). The result showed that Good Dairy Farming Practices (GDFP) has a positive effect on milk production.

Keywords: dairy cattle, GDFP, milk production, Sleman regency

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Authors: David Sarpong, Waleed Khursheed, Ernest Danquah, Erin Murphy

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Shigella is a pathogenic bacterium responsible for shigellosis, a severe diarrheal disease that claims the lives of immunocompromised individuals worldwide. To develop therapeutics against this disease, an understanding of the molecular mechanisms underlying the pathogen’s physiology is crucial. Small non-coding RNAs (sRNAs) have emerged as important regulators of bacterial physiology, including as components of toxin-antitoxin systems. In this study, we investigated the role of RyfA in S. flexneri physiology and virulence. RyfA, originally identified as an sRNA in Escherichia coli, is conserved within the Enterobacteriaceae family, including Shigella. Whereas two copies of ryfA are present in S. dysenteriae, all other Shigella species contain only one copy of the gene. Additionally, we identified a putative open reading frame within the RyfA transcript, suggesting that it may be a dual-functioning gene encoding a small protein in addition to its sRNA function. To study ryfA in vitro, we cloned the gene into an inducible plasmid and observed the effect on bacterial growth. Here, we report that RyfA production inhibits the growth of S. flexneri, and this inhibition is dependent on the contained open reading frame. In-silico analyses have revealed the presence of two divergently transcribed sRNAs, RyfB1 and RyfB2, which share nucleotide complementarity with RyfA and thus are predicted to function as anti-toxins. Our data demonstrate that RyfB2 has a stronger antitoxin effect than RyfB1. This regulatory pattern suggests a novel form of a toxin-antitoxin system in which the activity of a single toxin is inhibited to varying degrees by two sRNA antitoxins. Studies are ongoing to investigate the regulatory mechanism(s) of the antitoxin genes, as well as the downstream targets and mechanism of growth inhibition by the RyfA toxin. This study offers distinct insights into the regulatory mechanisms underlying Shigella physiology and may inform the development of new anti-Shigella therapeutics.

Keywords: sRNA, shigella, toxin-antitoxin, Type 1 toxin antitoxin

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Authors: U.N. Emiri, E. Moroyei

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Mycoflora associated with the seed rot disease of Mucuna sloanei and their effects on nutrient and phytochemical composition of the seeds were investigated. The fungal pathogens implicated in the seed rot disease were Rhizopus stolonifer, Aspergillus flavus, Aspergillus niger, and Fusarium oxysporum. The fungal isolates were aseptically inoculated into healthy M. Sloanei seeds and incubated for 7 days at room temperature of 25 ± 30c. The results of the proximate and mineral analysis in mg/100g of fungal infected and non-infected (control) seeds that were carried out revealed that there was an increase in Moisture and Carbohydrate content of the fungal infected seeds relative to the non-infected seeds (control). However, there was a decrease in Ash, Fibre, Lipid, and Protein content of the fungal infected seeds relative to the non-infected (control). It was observed that moisture had increased from 10.50 ± 0.16 in the non-infected seeds to 17.60 ± 0.20 in the infected samples and Carbohydrate content had also increased from 49.6 ± 0.25 in the non-infected to 52.50 ± 0.29 in the infected seeds. The following parameters decreased in the infected than in the non-infected seeds. They include Ash 2.60 ± 0.12, Crude fibre 1.9 ± 0.08, Lipid 6.50 ± 0.16, and Protein content 18.50 ± 0.06. Similarly, Calcium 2.50 ± 0.12, Phosphorus 1.80 + 0.12 and Potassium 1.80 + 0.09 increased in the infected than in the non-infected seed, while iron 0.20 ± 0.05, Sodium 0.02 ± 0.01 and Magnesium 0.06 ± 0.02 decreased in the infected seeds. All phytochemical contents analyzed increased in the infected seeds viz Tannim 0.50 ± 0.12, Oxalate 1.60 ± 0.05, Hydrogen cyanide 1.82 ± 0.06, and Saponin 2.50+0.28. However, the nutrient compositions and Phytochemical between the infected and non-infected seeds are not significantly different (p > 0.05).

Keywords: Mycoflora, mucuna sloanei, seeds, phytochemical, nutrient composition

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Authors: Hana Gebremariam Liliso

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This study investigates the factors contributing to the deterioration of thick asphalt pavements, such as rutting and cracking. We focus on the combined influence of traffic loads and pavement structure. This study uses a three-dimensional finite element model with a Mohr-Coulomb failure criterion to analyze the stress levels near the pavement's surface under realistic conditions. Our model considers various factors, including tire-pavement contact stresses, asphalt properties, moving loads, and dynamic analysis. This research suggests that cracking tends to occur between dual tires. Some key discoveries include the risk of cracking increases as temperatures rise; surface cracking at high temperatures is associated with distortional deformation; using a uniform contact stress distribution underestimates the risk of failure compared to realistic three-dimensional tire contact stress, particularly at high temperatures; the risk of failure is higher near the surface when there is a negative temperature gradient in the asphalt layer; and debonding beneath the surface layer leads to increased shear stress and premature failure around the interface.

Keywords: asphalt pavement, surface failure, 3d finite element model, multiaxial stress states, Mohr-Coulomb failure criterion

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Authors: Aisami A., Z. A. Adamu, Lawan Bulama

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Due to growing issues of crude oil pollution in both marine and terrestrial environments, Billions to Trillions of US Dollars were spent over the years for the treatment of this spill. There is an urgent need for effective bioremediation strategies. This current study focuses on the isolation and characterization of a crude oil-degrading bacterium from hydrocarbon-contaminated soil samples. Soil samples were collected from an oil spill site and subjected to enrichment culture techniques in a mineral salt medium supplemented with crude oil as the singular carbon source. The isolates were screened for their crude oil-degrading capabilities using gravimetric analysis. The most efficient isolation was identified through 16S rRNA gene sequencing. Cultural and physical conditions such pH, temperature salinity and crude oil concentrations were optimized. The isolates showed significant crude oil degradation efficiency, reducing oil concentration (2.5%) by 75% within 15 days of incubation. The strain was identified as Providencia sp. through molecular characterization, the sequence was deposited at the NCBI Genbank with accession number MN880494. The bacterium exhibited optimal growth at 32.5°C, pH 7.0 to 7.5, and in the presence of 1.5% (w/v) NaCl. The isolated Providencia sp. shows encouraging potential for bioremediation of crude oil-contaminated environments. This study successfully isolated and characterized a crude oil-degrading Providencia sp., highlighting its potential in bioremediation.

Keywords: crude oil degradation, providencia sp., bioremediation, hydrocarbon utilization, environmental pollution.

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Authors: Rym Taktak, Achwek Elghazel, Jamel Bouaziz

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In the present work, we explored the potential of tribological behavior of tricalcium phosphate-Fluorapatite (β Tcp-Fap) bioceramic which has attracted considerable attention for orthopedics and dental applications. The approximate representatives Fap-βTcp were respectively [{13.26 wt%, 86.74 wt%} {19.9 wt%, 80.1 wt%},{ 26.52 wt%, 73.48 wt%}, {33.16 wt%, 66.84 wt%} and {40 wt%, 60 wt%}. The effects of Fluorapatite additives on friction and wear behavior were studied and discussed. The wear test was conducted using pion-disk tribometer at room temperature under dry condition using a constant sliding speed of 0,063 m/s, and three loads 3, 5 and 8 N. The wear rate and friction coefficient of β Tcp with different additive amounts were compared. An Alumina ball specimens were used as the pin and flat surface β Tcp-Fap specimens as the antagonist counterface. The results show a huge difference between the wear rate of β TCP samples and the other β TCP-Fap composites for all normal forces applied. This result shows the beneficial effect of fluorapatite on the tribological behavior of the β TCP. Moreover, we note that β Tcp-26% Fap specimens exhibit, under dry condition, the lower friction coefficient and the smaller wear rate than other biocomposites. Thereby, the friction and wear behavior is influenced by the addition of fluorapatite, the applied normal force, and the sliding velocity. To extend the understanding of the wear process, the surface topography of β Tcp-26% Fap specimens and the wear track obtained during the wear tests were studied using a surface profilometer, optical microscopy, and scanning electron microscopy.

Keywords: alumina, bioceramic, friction and wear test, tricalcium phosphate

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Authors: Ryoko Yoshida, Jyunpei Yoshida, Hua Fang Yu, Yasushi Sasaki, Tetsuya Nagasaka

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Phosphorous is an important element for agriculture and industry and is a non-renewable resource. Especially, yellow phosphorus is an essential material in advanced industrial technology, but phosphorus resources were not produced in Japan at all, and all depend on imports. It has been suggested, however, that the remaining accessible reserves of phosphate ore will be depleted within 50 years. Therefore, alternative resources for phosphate ore must be found. In this research, we have developed a process that enables the production of high-purity yellow phosphorus from domestic unused phosphorus resources such as steelmaking slags. The process consists of two parts: (1) the production of crude phosphoric acid from wastes such as steelmaking slag; (2) producing high-purity yellow phosphorus by low-temperature carbothermic reduction of phosphoric acid (H₃PO₄). The details of the carbothermic reduction of phosphoric acid are presented in this paper. Yellow phosphorus is commercially produced by carbothermic reduction of phosphate ore in an electric arc furnace at more than 1673K. In the newly developed system, gaseous P₄O₁₀ evaporated from H₃PO₄ is successfully reduced to yellow phosphorus by using carbon packed bed at less than 1273K. To meet the depletion of phosphate ore, the proposed process in this study to produce yellow phosphorus by carbothermic reduction of H₃PO₄ that are extracted from dephosphorization slags will be one of the effective and economical solutions.

Keywords: carbothermic reduction, phosphoric acid, dephosphorization slags, yellow phosphorus

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Authors: Luxy Grebers Swend Sinaga, Akhmaloka

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The global energy crisis, triggered by declining fossil The global energy crisis, triggered by declining fossil fuel reserves and exacerbated by population growth and increasing energy demand, was driven the development of renewable energy sources. One of the green energy alternatives being developed is biodiesel. Transesterification is at the core of biodiesel production, where fatty acids in oil are converted into methyl esters with the aid of a catalyst. Lipases exhibit high activity and stability during catalysis, especially under harsh conditions. Lipase (Lk1) isolated from organic waste compost at the Bandung Institute of Technology, Bandung, West Java, shows promising potential in this field. The thermostable lipase was purified using Ni-NTA affinity chromatography, followed by SDS-PAGE analysis for purity confirmation. Characterizing the transesterification activity of Lk1 is essential for assessing its effectiveness in converting oil into biodiesel, including methyl esters. The results of this study showed that Lk1 exhibited the highest activity on a methyl palmitate substrate, with an optimum temperature of 60°C, very stable activity in the non-polar solvent n-hexane, and was able to maintain its optimum activity for up to 1 hour. These characters make Lk1 highly suitable for biodiesel production, as it meets the main criteria for the transesterification process in producing renewable energy.

Keywords: biodiesel, lipase Lk1, transesterification, renewable energy, thermostability

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Authors: Roongtiwa Chobchuen, Siriporn Mongkholthawornchai, Boonsong Hatawaikarn, Uriwan Chaichangreet, Kobkaew Thongtid, Pusda Pukdeekumjorn, Panita Limpawattana

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Background: Age-friendly nursing service system in Srinagarind Hospital has been developed continuously based on the value and cultural background of Thailand which corporates with the modified WHO’s Age friendly Primary Care Service System. It consists of 3 issues; 1) development of staff training, 2) age-friendly service and 3) appropriate physical environment. Objective: To evaluate the efficacy of Age-friendly Nursing Service System: KKU (AFNS:KKU) model and to evaluate factors associated with nursing perception with AFN:KKU. Study design: Descriptive study Setting: 31 wards that served older patients in Srinagarind Hospital Populations: Nursing staff from 11 departments (31 wards) Instrument: Age-friendly nursing care scale as perceived by hospitalized older person Procedure and statistical analysis: All participants were asked questions using age-friendly nursing care scale as perceived by hospitalized older person questionnaires. Descriptive statistics and multiple logistic regression analyses were used to analyse the outcomes. Results: There were 337 participants recruited in this study. The majority of them were women (92%) with the mean ages of 29 years and 77.45% were nurse practitioners. They had average nursing experiences of 5 years. The average scores of age-friendly nursing care scale were high and highest in the area of attitude and communication. Age, sex, educational level, duration of work among, and having experience in aging training were not associated with nursing perception where type of department was an independent factor. Nurses from department of Surgery and Orthopedic, Eye and ENT, special ward and Obstetrics and Gynecological had significant greater perception than nurses from Internal Medicine Department (p < 0.05). Conclusion: Nurses had high scores in all dimensions of age-friendly concept. The result indicates that nurses have good attitude to aging care which can lead to improve quality of care. Organization should support other domains of ageing care to achieve greater effectiveness in geriatric care.

Keywords: age-friendly, nursing service system, excellence model, geriatric care

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Authors: Florian Tille, Heide Weishaar, Bernhard Gibis, Susanne Schnitzer

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Introduction: The quality of patient-doctor communication and of written health information is central to organizational health literacy (HL). Whether patients understand their doctors’ explanations and textual material on health, however, is understudied. This study identifies the overall levels of patient understanding of health information and its associations with patients’ social characteristics in outpatient health care in Germany. Materials & Methods: This analysis draws on data collected via a 2017 national health survey with a sample of 6,105 adults. Quality of communication was measured for consultations with general practitioners (GPs) and specialists (SPs) via the Ask Me 3 program questions, and through a question on written health material. Correlations with social characteristics were explored employing bivariate and multivariate logistic regression analyses. Results: Over 90% of all respondents reported that they had understood their doctors’ explanations during the last consultation. Failed understanding was strongly correlated with patients’ very poor health (Odds Ratio [OR]: 5.19; 95% confidence interval [CI]: 2.23–12.10; ref. excellent/very good health), current health problem (OR: 6.54, CI: 1.70–25.12; ref. preventive examination) and age 65 years and above (OR: 2.97, CI: 1.10–8.00; ref. 18 to 34 years). Fewer patients answered they understood written material well (86.7% for las visit at GP, 89.7% at SP). Understanding written material poorly was highly associated with basic education (OR: 4.20, CI: 2.76–6.39; ref. higher education) and 65 years old and above (OR: 2.66, CI: 1.43–4.96). Discussion: Overall ratings of oral patient-doctor communication and written communication of health information are high. Yet, a considerable share of patients reports not-understanding their doctors and poor understanding of the written health-related material. Interventions that can contribute to improving organizational HL in outpatient care in Germany include HL training for doctors, reducing system barriers to easily-accessible health information for patients and combining oral and written health communication means. Conclusion: This work adds to the study of organizational HL in Germany. To increase patient understanding of health-relevant information and thereby possibly reduce health disparities, meeting the communication needs especially of persons in different age groups, with basic education and in very poor health is suggested.

Keywords: health survey, organizational health literacy, patient-doctor communication, social characteristics, outpatient care, Ask Me 3

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Authors: Baljit Soroya

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Transnational communities are as a consequence of greater mobility of people, globalization and digitization have had a major impact on international relations and diasporas in the context of external conflicts. To a significant extent conflicts are becoming deterritorialised and informed by both internal (state politics) and external (foreign policy) players such as in Iraq and Syria leading to forced migration of unprecedented levels within the last two decades. The situation of forced migrants has, it is suggested, worsened as a consequence of the neo-liberal policies and requirements of organizations such as the European Bank. A case example of this being that of Greece, and the exacerbation of insecurity for Greek nationals and the demonization of refugees seeking sanctuary. This has been as a consequence, in part, of the neoliberal dogma of the European Bank. The article analyses the complex intersection of the real and perceived threats of international terrorism and the manner in which UK migration policy and Practice is unfolding. The policy and practice developments are explored in the context of the shift in politics in both the UK and wider Europe to the far right and the drift of main stream political parties to the right. In many cases, the mainstream political groupings, have co-opted the fears as presented by far right organization for political their own political gains, such as in the UK and France In its analysis it will be argued that, whilst international terrorism is an issue of concern, however in the context of the UK it is not of the same scale as the effects of climate change or indeed domestic violence. Given that, the question has to be asked why the threat of international terrorism is having such an impact on UK migration policy and practice and, specifically refugees. Furthermore, it is argued that this policy and practice are being formulated within a narrative that portrays migrants as the problem both in relation to terrorism and the disenfranchisement of ‘ordinary white communities’. The intersectionality of social, economic inequalities, fear of international terrorism, increase in conflicts and the political climate have contributed to a lack of trust of political establishments that have in turn sought to impress the public with their anti-immigrant rhetoric and policy agendas. The article ends by suggesting that whilst politics and political affiliations have become fractured there are nevertheless spaces for collective action, particularly in relation to issues of refugees.

Keywords: international terrorism, migration policy, conflict, media, community, politics

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Authors: Sospeter P. Maganga, Alphonce Wikedzi, Mussa D. Budeba, Samwel V. Manyele

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This study characterizes complex gold ores (elemental and mineralogical composition, gold distribution, ore grindability, and mineral liberation) for preliminary process selection. About 200 kg of ore samples were collected from each location using systematic sampling by mass interval. Ores were dried, crushed, milled, and split into representative sub-samples (about 1 kg) for elemental and mineralogical composition analyses using X-ray fluorescence (XRF), fire assay finished with Atomic Absorption Spectrometer (AAS), and X-ray Diffraction (XRD) methods, respectively. The gold distribution was studied on size-by-size fractions, while ore grindability was determined using the standard Bond test. The mineral liberation analysis was conducted using ThermoFisher Scientific Mineral Liberation Analyzer (MLA) 650, where unsieved polished grain mounts (80% passing 700 µm) were used as MLA feed. Two MLA measurement modes, X-ray modal analysis (XMOD) and sparse phase liberation-grain X-ray mapping analysis (SPL-GXMAP), were employed. At least two cyanide consumers (Cu, Fe, Pb, and Zn) and kinetics impeders (Mn, S, As, and Bi) were present in all locations investigated. Copper content at Kapanda (0.77% Cu) and Ibindi (7.48% Cu) exceeded the recommended threshold of 0.5% Cu for direct cyanidation. The gold ore at Ibindi indicated a higher rate of grinding compared to other locations. This could be explained by the highest grindability (2.119 g/rev.) and lowest Bond work index (10.213 kWh/t) values. The pyrite-marcasite, chalcopyrite, galena, and siderite were identified as major gold, copper, lead, and iron-bearing minerals, respectively, with potential for economic extraction. However, only gold and copper can be recovered under conventional milling because of grain size issues (galena is exposed by 10%) and process complexity (difficult to concentrate and smelt iron from siderite). Therefore, the preliminary process selection is copper flotation followed by gold cyanidation for Kapanda and Ibindi ores, whereas gold cyanidation with additives such as glycine or ammonia is selected for Mawemeru and Itumbi ores because of low concentrations of Cu, Pb, Fe, and Zn minerals.

Keywords: complex gold ores, mineral liberation, ore characterization, ore grindability

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Authors: Fatiha Atmani, Lamia Djellab, Nacera Yeddou Mezenner, Zohra Bensaadi

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Generally, bilge waters can be briefly defined as saline and greasy wastewaters. The oil and grease are mixed with the sea water, which affects many marine species. Bilge water is a complex mixture of various compounds such as solvents, surfactants, fuel, lubricating oils, and hydraulic oils. It is resulted mainly by the leakage from the machinery and fresh water washdowns,which are allowed to drain to the lowest inner part of the ship's hull. There are several physicochemical methods used for bilge water treatment such as biodegradation electrochemical and electro-coagulation/flotation.The research herein presented discusses adsorption as a method to treat bilge water and eggshells were studied as an adsorbent. The influence of operating parameters as contact time, temperature and adsorbent dose (0,2 - 2g/l) on the removal efficiency of Chemical oxygen demand, COD, and turbidity was analyzed. The bilge wastewater used for this study was supplied by Harbour Bouharoune. Chemical oxygen demand removal increased from 26.7% to 68.7% as the adsorbent dose increased from 0.2 to 2 g. The kinetics of adsorption by eggshells were fast, reaching 55 % of the total adsorption capacity in ten minutes (T= 20°C, pH =7.66, m=2g/L). It was found that the turbidity removal efficiency decreased and 95% were achieved at the end of 90 min reaction. The adsorption process was found to be effective for the purification of bilge water and pseudo-second-order kinetic model was fitted for COD removal.

Keywords: adsorption, bilge water, eggshells and kinetics, equilibrium and kinetics

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Authors: Kaustuvmani Patowary, Suresh Deka

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Oil pollution accidents, nowadays, have become a common phenomenon and have caused ecological and social disasters. Microorganisms with high oil-degrading performance are essential for bioremediation of petroleum hydrocarbon. In this investigation, an effective biosurfactant producer and hydrocarbon degrading bacterial strain, Pseudomonas sp.PG1 (identified by 16s rDNA sequencing) was isolated from hydrocarbon contaminated garage soil of Pathsala, Assam, India, using crude oil enrichment technique. The growth parameters such as pH and temperature were optimized for the strain and upto 81.8% degradation of total petroleum hydrocarbon (TPH) has been achieved after 5 weeks when grown in mineral salt media (MSM) containing 2% (w/v) crude oil as the carbon source. The biosurfactant production during the course of hydrocarbon degradation was monitored by surface tension measurement and emulsification activity. The produced biosurfactant had the ability to decrease the surface tension of MSM from 72 mN/m to 29.6 mN/m, with the critical micelle concentration (CMC)of 56 mg/L. The biosurfactant exhibited 100% emulsification activity on crude oil. FTIR spectroscopy and LCMS-MS analysis of the purified biosurfactant revealed that the biosurfactant is Rhamnolipidic in nature with several rhamnolipid congeners. Gas Chromatography-Mass spectroscopy (GC-MS) analysis clearly demonstrated that the strain PG1 efficiently degrade different hydrocarbon fractions of the crude oil. The study suggeststhat application of the biosurfactant producing strain PG1 as an appropriate candidate for bioremediation of crude oil contaminants.

Keywords: petroleum hydrocarbon, hydrocarbon contamination, bioremediation, biosurfactant, rhamnolipid

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Authors: Freddy Munzhelele

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Setting: the empirical research has shown that the life cycle theory has an impact on the firms’ financing decisions, particularly the dividend pay-outs. Accordingly, the life cycle theory posits that as a firm matures, it gets to a level and capacity where it distributes more cash as dividends. On the other hand, the young firms prioritise investment opportunities sets and their financing; thus, they pay little or no dividends. The research on firms’ financing decisions also demonstrated, among others, the adoption of trade-off and pecking order theories on the dynamics of firms capital structure. The trade-off theory talks to firms holding a favourable position regarding debt structures particularly as to the cost and benefits thereof; and pecking order is concerned with firms preferring a hierarchical order as to choosing financing sources. The case of life cycle hypothesis explaining the financial managers’ decisions as regards the firms’ capital structure dynamics appears to be an interesting link, yet this link has been neglected in corporate finance research. If this link is to be explored as an empirical research, the financial decision-making alternatives will be enhanced immensely, since no conclusive evidence has been found yet as to the dynamics of capital structure. Aim: the aim of this study is to examine the impact of life cycle theory on the capital structure dynamics trade-off and pecking order theories of firms listed in retail, industrial and mining sectors of the JSE. These sectors are among the key contributors to the GDP in the South African economy. Design and methodology: following the postpositivist research paradigm, the study is quantitative in nature and utilises secondary data obtainable from the financial statements of sampled firm for the period 2010 – 2022. The firms’ financial statements will be extracted from the IRESS database. Since the data will be in panel form, a combination of the static and dynamic panel data estimators will used to analyse data. The overall data analyses will be done using STATA program. Value add: this study directly investigates the link between the life cycle theory and the dynamics of capital structure decisions, particularly the trade-off and pecking order theories.

Keywords: life cycle theory, trade-off theory, pecking order theory, capital structure, JSE listed firms

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Authors: Bobuchi Ken-Opurum

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The impacts of climate change on urban settlements is growing. In the global south, communities are even more vulnerable and suffer there is an increased vulnerability from due to climate change disasters such as flooding and high temperatures. This is primarily due to high intensity rainfall, low-lying coasts, inadequate infrastructure, and limited resources. According to the Emergency Events Database, floods were the leading cause of disaster -based deaths in the global south between 2006 and 2015. This includes deaths from heat stress related health outcomes. Adapting to climate vulnerabilities is paramount in reducing the significant redevelopment costs from climate disasters. Governments and urban planners provide top-down approaches such as evacuation, and disaster and emergency communication. While they address infrastructure and public services, they are not always able to address the immediate and critical day to day needs of poor and vulnerable populations. There is growing evidence that some bottom-up strategies and grassroots initiatives of self-build housing such as in urban informal settlements are successful in coping and adapting to hydroclimatic impacts. However, these research findings are not consolidated and the evaluation of the resilience outcomes of the bottom-up strategies are limited. Using self-build housing as a model for sustainable and resilient urban planning, this research aimed to consolidate the flood and heat stress resilient design solutions, analyze the effectiveness of these solutions, and develop guidelines and methods for adopting these design solutions into mainstream housing in megathermal climates. The methodological approach comprised of analyses of over 40 ethnographic based peer reviewed literature, white papers, and reports between the years 2000 and 2019 to identify coping strategies and grassroots initiatives that have been applied by occupants and communities of the global south. The results of the research provide a consolidated source and prioritized list of the best bottom-up strategies for communities in megathermal climates to improve the lives of people in some of the most vulnerable places in the world.

Keywords: resilient, design, megathermal, climate change

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Authors: Barbora Valockova

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Scholars recommend the establishment of a multilateral coordination mechanism by ASEAN, such as an infrastructure forum, to contain the China-Japan infrastructure financing competition in the region. However, they do not systematically investigate the reasons for its absence. This paper aims to fill the gap by addressing the following question: Why has ASEAN been unable to set up any multilateral coordination mechanism to soften the China-Japan infrastructure financing competition? This paper argues that ASEAN has not been able to set up such a mechanism due to its limited centrality in connectivity. This limited centrality decreases ASEAN’s ability to manage the China-Japan competition in a more comprehensive and coordinated way. Rather, ASEAN acts as a scope setter in connectivity, although this is not completely ineffective. This paper is divided into four sections. The first section explores the key tenets of the concept of ASEAN centrality in connectivity, which is under-examined in the current literature. The second section examines the extent to which ASEAN limited centrality in connectivity is being respected by China and Japan. The third section analyses how various stakeholders, such as ASEAN member states, their leaders and bureaucracy, and foreign private companies prevent ASEAN from attaining stronger centrality. The last section concludes and offers recommendations. Data is gathered using primary sources (official ASEAN, Chinese, and Japanese documents, interviews, etc.) and secondary material. By providing a nuanced analysis of ASEAN centrality in connectivity and developing a new operationalization of the concept, this paper aims to contribute to the international relations literature on ASEAN centrality. Initial findings suggest that while ASEAN limited centrality in connectivity has some effectiveness, it is not sufficient for setting up a multilateral coordination mechanism. While it represents a solid departure point, any potential possessed by ASEAN to evolve beyond a scope setter in connectivity is hampered by stakeholders involved in infrastructure development. While these players and their interactions can have both positive and negative effects on the scope set by ASEAN, it is unlikely that they would allow ASEAN to become the real central player. There can be no stronger ASEAN centrality in connectivity without ASEAN unity and neutrality. However, the last two factors are difficult to attain in the context of infrastructure development since ASEAN member states and stakeholders all have their styles and preferences. All other things being equal, these circumstances favor a loose, vague, and quasi-prescriptive arrangement among the relevant stakeholders.

Keywords: ASEAN centrality, China-Japan infrastructure competition, connectivity, scope setter

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Authors: A. N. Fouda

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A novel well identified hexagonal graphene oxide (GO) nano-sheets were synthesized using modified Hummer method. Low temperature thermal reduction at 350°C in air ambient was performed. After thermal reduction, typical few layers of thermal reduced GO (TRGO) with dimension of few hundreds nanometers were observed using high resolution transmission electron microscopy (HRTEM). GO has a lot of structure models due to variation of the preparation process. Determining the atomic structure of GO is essential for a better understanding of its fundamental properties and for realization of the future technological applications. Structural characterization was identified by x-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR) measurements. A comparison between exper- imental and theoretical IR spectrum were done to confirm the match between experimentally and theoretically proposed GO structure. Partial overlap of the experimental IR spectrum with the theoretical IR was confirmed. The electrochemical properties of TRGO nano-sheets as electrode materials for supercapacitors were investigated by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements. An enhancement in supercapacitance after reduction was confirmed and the area of the CV curve for the TRGO electrode is larger than those for the GO electrode indicating higher specific capacitance which is promising in super-capacitor applications

Keywords: hexagonal graphene oxide, thermal reduction, cyclic voltammetry

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Authors: Clarinda V. Nhangumbe, Ercília Sousa

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Weather Derivatives are financial instruments used to cover non-catastrophic weather events and can be expressed in the form of standard or plain vanilla products, structured or exotics products. The underlying asset, in this case, is the weather index, such as temperature, rainfall, humidity, wind, and snowfall. The complexity of the Weather Derivatives structure shows the weakness of the Black Scholes framework. Therefore, under the risk-neutral probability measure, the option price of a weather contract can be given as a unique solution of a two-dimensional partial differential equation (parabolic in one direction and hyperbolic in other directions), with an initial condition and subjected to adequate boundary conditions. To calculate the price of the option, one can use numerical methods such as the Monte Carlo simulations and implicit finite difference schemes conjugated with Semi-Lagrangian methods. This paper is proposed two explicit methods, namely, first-order upwind in the hyperbolic direction combined with Lax-Wendroff in the parabolic direction and first-order upwind in the hyperbolic direction combined with second-order upwind in the parabolic direction. One of the advantages of these methods is the fact that they take into consideration the boundary conditions obtained from the financial interpretation and deal efficiently with the different choices of the convection coefficients.

Keywords: incomplete markets, numerical methods, partial differential equations, stochastic process, weather derivatives

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Authors: Sandra C. L. Dorea, Joann K. Whalen, Yixin Shao, Oumarou Savadogo

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The major challenge for industries that rely on fossil fuels in manufacturing processes or to provide goods and services is to lower their CO2 emissions, as the case for the manufacture of Portland cement. Feasible materials for this purpose can include agro-industrial or agricultural wastes, which are termed 'biosilica' since the silica was contained in a biological matrix (biomass). Corn cob (CC) has some characteristics that make it a good candidate as biosilica source: 1) it is an abundant grain crop produced around the world; 2) more production means more available residues is left in the field to be used. This work aims to evaluate the CC collected from different farms in Canada during the corn harvest in order to see if they can be used together as a biosilica source. The characterization of the raw CC was made in the physical, chemical, and thermal way. The moisture content, the granulometry, and the morphology were also analyzed. The ash content measured was 2,1%. The Thermogravimetric Analysis (TGA) and its Derivative (DTG) evaluated of CC as a function of weight loss with temperature variation ranging between 30°C and 800°C in an atmosphere of N2. The chemical composition and the presence of silica revealed that the different sources of the CC do not interfere in its basic chemical composition, which means that this kind of waste can be used together as a source of biosilica no matter where they come from. Then, this biosilica can partially replace the cement Portland making sustainable cementitious mixtures and contributing to reduce the CO2 emissions.

Keywords: biosilica, characterization, corn cob, sustainable cementitious materials

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Authors: U. Gunal, H. I. Turgut, H. Gurler, S. Kaya

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There are many ever-increasing and newly emerging problems with rapid population growth in the world. With the increase in people's quality of life in our daily life, acoustic comfort has become an important feature in the textile industry. In order to meet all these expectations in people's comfort areas and survive in challenging competitive conditions in the market without compromising the customer product quality expectations of textile manufacturers, it has become a necessity to bring functionality to the products. It is inevitable to research and develop materials and processes that will bring these functionalities to textile products. The noise we encounter almost everywhere in our daily life, in the street, at home and work, is one of the problems which textile industry is working on. It brings with it many health problems, both mentally and physically. Therefore, noise control studies become more of an issue. Besides, materials used in noise control are not sufficient to reduce the effect of the noise level. The fabrics used in acoustic studies in the textile industry do not show sufficient performance according to their weight and high cost. Thus, acoustic textile products can not be used in daily life. In the thesis study, the attributions used in the noise control and building acoustics studies in the literature were analyzed, and the product with the highest damping value that a textile material will have was designed, manufactured, and tested. Optimum values were obtained by using different material samples that may affect the performance of the acoustic material. Acoustic measurement methods should be applied to verify the acoustic performances shown by the parameters and the designed three-dimensional structure at different values. In the measurements made in the study, the device designed for determining the acoustic performance of the material for both the impedance tube according to the relevant standards and the different noise types in the study was used. In addition, sound records of noise types encountered in daily life are taken and applied to the acoustic absorbent fabric with the aid of the device, and the feasibility of the results and the commercial ability of the product are examined. MATLAB numerical computing programming language and libraries were used in the frequency and sound power analyses made in the study.

Keywords: acoustic, egg crate, fabric, textile

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Authors: Raj Banerjee, Aniruddha Sengupta

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An earthquake event, associated with a typical fault rupture, initiates at the source, propagates through a rock or soil medium and finally daylights at a surface which might be a populous city. The detrimental effects of an earthquake are often quantified in terms of the responses of superstructures resting on the soil. Hence, there is a need for the estimation of amplification of the bedrock motions due to the influence of local site conditions. In the present study, field borehole log data of Mangalwadi and Walkeswar sites in Mumbai city are considered. The data consists of variation of SPT N-value with the depth of soil. A correlation between shear wave velocity (Vₛ) and SPT N value for various soil profiles of Mumbai city has been developed using various existing correlations which is used further for site response analysis. MATLAB program is developed for studying the ground response analysis by performing two dimensional linear and equivalent linear analysis for some of the typical Mumbai soil sites using pure shear (Multi Point Constraint) boundary condition. The model is validated in linear elastic and equivalent linear domain using the popular commercial program, DEEPSOIL. Three actual earthquake motions are selected based on their frequency contents and durations and scaled to a PGA of 0.16g for the present ground response analyses. The results are presented in terms of peak acceleration time history with depth, peak shear strain time history with depth, Fourier amplitude versus frequency, response spectrum at the surface etc. The peak ground acceleration amplification factors are found to be about 2.374, 3.239 and 2.4245 for Mangalwadi site and 3.42, 3.39, 3.83 for Walkeswar site using 1979 Imperial Valley Earthquake, 1989 Loma Gilroy Earthquake and 1987 Whitter Narrows Earthquake, respectively. In the absence of any site-specific response spectrum for the chosen sites in Mumbai, the generated spectrum at the surface may be utilized for the design of any superstructure at these locations.

Keywords: deepsoil, ground response analysis, multi point constraint, response spectrum

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Authors: Catia S. A. Sima, K. Bousson

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Congestion in the Terminal Maneuvering Areas (TMAs) of larger airports impacts all aspects of air traffic flow, not only at national level but may also induce arrival delays at international level. Hence, there is a need to monitor appropriately the air traffic flow in TMAs so that efficient decisions may be taken to manage their occupancy rates. It would be desirable to physically increase the existing airspace to accommodate all existing demands, but this question is entirely utopian and, given this possibility, several studies and analyses have been developed over the past decades to meet the challenges that have arisen due to the dizzying expansion of the aeronautical industry. The main objective of the present paper is to propose concepts to manage and reduce the degree of uncertainty in the air traffic operations, maximizing the interest of all involved, ensuring a balance between demand and supply, and developing and/or adapting resources that enable a rapid and effective adaptation of measures to the current context and the consequent changes perceived in the aeronautical industry. A central task is to emphasize the increase in air traffic flow management capacity to the present day, taking into account not only a wide range of methodologies but also equipment and/or tools already available in the aeronautical industry. The efficient use of these resources is crucial as the human capacity for work is limited and the actors involved in all processes related to air traffic flow management are increasingly overloaded and, as a result, operational safety could be compromised. The methodology used to answer and/or develop the issues listed above is based on the advantages promoted by the application of Markov Chain principles that enable the construction of a simplified model of a dynamic network that describes the air traffic flow behavior anticipating their changes and eventual measures that could better address the impact of increased demand. Through this model, the proposed concepts are shown to have potentials to optimize the air traffic flow management combined with the operation of the existing resources at each moment and the circumstances found in each TMA, using historical data from the air traffic operations and specificities found in the aeronautical industry, namely in the Portuguese context.

Keywords: air traffic flow, terminal maneuvering area, TMA, air traffic management, ATM, Markov chains

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Authors: Esmaeil Abbaszadeh Molaei, Zongyan Zhou, Aibing Yu

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The applications of liquid fluidizations have been increased in many parts of industries such as particle classification, backwashing of granular filters, crystal growth, leaching and washing, and bioreactors due to high-efficient liquid–solid contact, favorable mass and heat transfer, high operation flexibilities, and reduced back mixing of phases. In most of these multiphase operations the particles properties, i.e. size, density, and shape, may change during the process because of attrition, coalescence or chemical reactions. Previous studies, either experimentally or numerically, mainly have focused on studies of liquid-solid fluidized beds containing spherical particles; however, the role of particle shape on the hydrodynamics of liquid fluidized beds is still not well-known. A three-dimensional Discrete Element Model (DEM) and Computational Fluid Dynamics (CFD) are coupled to study the influence of particles shape on particles and liquid flow patterns in liquid-solid fluidized beds. In the simulations, ellipsoid particles are used to study the shape factor since they can represent a wide range of particles shape from oblate and sphere to prolate shape particles. Different particle shapes from oblate (disk shape) to elongated particles (rod shape) are selected to investigate the effect of aspect ratio on different flow characteristics such as general particles and liquid flow pattern, pressure drop, and particles orientation. First, the model is verified based on experimental observations, then further detail analyses are made. It was found that spherical particles showed a uniform particle distribution in the bed, which resulted in uniform pressure drop along the bed height. However for particles with aspect ratios less than one (disk-shape), some particles were carried into the freeboard region, and the interface between the bed and freeboard was not easy to be determined. A few particle also intended to leave the bed. On the other hand, prolate particles showed different behaviour in the bed. They caused unstable interface and some flow channeling was observed for low liquid velocities. Because of the non-uniform particles flow pattern for particles with aspect ratios lower (oblate) and more (prolate) than one, the pressure drop distribution in the bed was not observed as uniform as what was found for spherical particles.

Keywords: CFD, DEM, ellipsoid, fluidization, multiphase flow, non-spherical, simulation

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Authors: M. Khaledi Pour, P. Akbartehrani, M. Amini, M. Khani, M. Mohajeri Tehrani, R. Radi, B. Shokri

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Diabetic Foot Ulcer (DFU) is one of the costly severe complications of diabetes. Neuropathy and Peripheral Arterial Disease (PAD) due to diabetes are significant causes of this complication. In 10 years the patients with DFUs are twice as likely to die as patients without DFUs. Cold Atmospheric Plasma (CAP) is a promising tool for medical purposes. CAP generate reactive species at room temperature and are effective in killing bacteria and fibroblast proliferation. These CAP-based tools produce NO, which has bactericidal and angiogenesis properties. It also showed promising effects in the DFUs surface reduction and the time to wound closure. In this paper, we evaluated the effect of the Argon Plasma Jet (APJ) on the healing process of the Wagner Grade 2 DFUs in a randomized clinical trial. The 20 kHz sinusoidal voltage frequency derives the APJ. Patients (n=20) were randomly double-blinded assigned into two groups. These groups receive the standard care (SC, n=10) and the standard care with APJ treatment (SC+APJ, n=10) for five sessions in four weeks. The results showed that the APJ treatment along standard care could reduce the wound surface by 20 percent more than the standard care. Also, It showed a more influential role in controlling wound infection.

Keywords: argon plasma jet, cold atmospheric plasma, diabetes, diabetic foot ulcer

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Authors: Hye Jin Kim, Hwa Sung Shin

Abstract:

Ischemic stroke means the caused brain damage due to neurological defects, occurring occlusion of cerebral vascular resulting in thrombus or embolism. t-PA (tissue Plasminogen Activator) is the only thrombolytic agent passed the FDA (Food and Drug Administration). However, t-PA directly dissolves the thrombus (direct activity) through fibrinolysis, showing side effects such as re-occlusion. In this study, we evaluated the thrombolytic activities of the serine protease extracted from lugworms inhabiting tidal flats. The new serine protease identified as 38 kDa by SDS-PAGE was not toxic to brain endothelial cells line (hCMEC/D3). Also, the plasmin synthesis inhibition activity (indirect activity) of the new serine protease was confirmed through fibrin zymography assay and fibrin plate assay. It was higher than direct activity as compared to u-PA (urokinase Plasminogen Activator). The activities were found to be maintained at a wide range of temperature (4-70 ℃) and pH 7-10 compared to previous thrombolytic agents from the azocasein assay. In addition, the new serine protease has shown anticoagulant activity from fibrinogenolytic activity assay. In conclusion, the serine protease in lug worms inhabiting the tidal flats could be considered a promising thrombolytic candidate for the treatment of ischemic stroke.

Keywords: alkaline serine protease, bifunctional thrombolytic activity, fibrinolytic activity, ischemic stroke, lug worms

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Authors: Muhammad Asim

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Background: Less than half of women in South Asia (SA) use any modern contraceptive method which leads to a huge burden of unintended pregnancies, unsafe abortions, maternal deaths, and socioeconomic loss. Women empowerment plays a pivotal role in improving various health seeking behaviours, including contraceptive use. The objective of this study to explore the association between women's empowerment and modern contraceptive, among rich and poor segment of population in SA. Methods: We used the most recent, large-scale, demographic health survey data of five South Asian countries, namely Afghanistan, Pakistan, Bangladesh, India, and Nepal. The outcome variable was the current use of modern contraceptive methods. The main exposure variable was a combination (interaction) of socio-economic status (SES) and women’s level of empowerment (low, medium, and high), where SES was bifurcated into poor and rich; and women empowerment was divided into three categories: decision making, attitude to violence and social independence. Moreover, overall women empowerment indicator was also created by using three dimensions of women empowerment. We applied both descriptive statistics and multivariable logistic regression techniques for data analyses. Results: Most of the women possessed ‘medium’ level of empowerment across South Asian Countries. The lowest attitude to violence empowerment was found in Afghanistan, and the lowest social independence empowerment was observed in Bangladesh across SA. However, Pakistani women have the lowest decision-making empowerment in the region. The lowest modern contraceptive use (22.1%) was found in Afghanistan and the highest (53.2%) in Bangladesh. The multivariate results depict that the overall measure of women empowerment does not affect modern contraceptive use among poor and rich women in most of South Asian countries. However, the decision-making empowerment plays a significant role among both poor and rich women to use modern contraceptive methods across South Asian countries. Conclusions: The effect of women’s empowerment on modern contraceptive use is not consistent across countries, and among poor and rich segment of population. Of the three dimensions of women’s empowerment, the autonomy of decision making in household affairs emerged as a stronger determinant of mCPR as compared with social independence and attitude towards violence against women.

Keywords: women empowerment, contraceptive use, South Asia, women autonomy

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Authors: Ishith Seth, Lyndel Hewitt, Takako Yabe, James Wykes, Jonathan Clark, Bruce Ashford

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Background: Vastus lateralis (VL) can be used to reconstruct defects of the head and neck. Whilst the advantages are documented, donor-site morbidity is not well described. This study aimed to assess donor-site morbidity after VL flap harvest. The results will determine future directions for preventative and post-operative care to improve patient health outcomes. Methods: Ten participants (mean age 55 years) were assessed for the presence of donor-site morbidity after VL harvest. Musculoskeletal (pain, muscle strength, muscle length, tactile sensation), quality of life (SF-12), and lower limb function (lower extremity function, gait (function and speed), sit to stand were assessed using validated and standardized procedures. Outcomes were compared to age-matched healthy reference values or the non-operative side. Analyses were conducted using descriptive statistics and non-parametric tests. Results: There was no difference in muscle strength (knee extension), muscle length, ability to sit-to-stand, or gait function (all P > 0.05). Knee flexor muscle strength was significantly less on the operated leg compared to the non-operated leg (P=0.02) and walking speed was slower than age-matched healthy values (P<0.001). Thigh tactile sensation was impaired in 89% of participants. Quality of life was significantly less for the physical health component of the SF-12 (P<0.001). The mental health component of the SF-12 was similar to healthy controls (P=0.26). Conclusion: There was no effect on donor site morbidity with regards to knee extensor strength, pain, walking function, ability to sit-to-stand, and muscle length. VL harvest affected donor-site knee flexion strength, walking speed, tactile sensation, and physical health-related quality of life.

Keywords: vastus lateralis, morbidity, head and neck, surgery, donor-site morbidity

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