Search results for: high corrosion resistance

Authors: Mohammad R. Irshidat, Mohammed H. Al-Saleh, Mahmoud Al-Shoubaki

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This paper investigates the viability of using carbon fiber reinforced epoxy composites modified with carbon nano tubes to strengthening reinforced concrete (RC) columns. Six RC columns was designed and constructed according to ASCE standards. The columns were wrapped using carbon fiber sheets impregnated with either neat epoxy or CNTs modified epoxy. These columns were then tested under concentric axial loading. Test results show that; compared to the unwrapped specimens; wrapping concrete columns with carbon fiber sheet embedded in CNTs modified epoxy resulted in an increase in its axial load resistance, maximum displacement, and toughness values by 24%, 109% and 232%, respectively. These results reveal that adding CNTs into epoxy resin enhanced the confinement effect, specifically, increased the axial load resistance, maximum displacement, and toughness values by 11%, 6%, and 19%, respectively compared with columns strengthening with carbon fiber sheet embedded in neat epoxy.

Keywords: CNT, epoxy, carbon fiber, RC columns

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Authors: Ammar Maziz, Mostapha Tarfaoui, Said Rechak

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The high mechanical performance of composite pipes can be adversely affected by their low resistance to impact loads. Loads in dynamic origin are dangerous and cause consequences on the operation of pipes because the damage is often not detected and can affect the structural integrity of composite pipes. In this work, an advanced 3-D finite element (FE) model, based on the use of intralaminar damage models was developed and used to predict damage under low-velocity impact. The performance of the numerical model is validated with the confrontation with the results of experimental tests. The results show that at low impact energy, the damage happens mainly by matrix cracking and delamination. The model capabilities to simulate the low-velocity impact events on the full-scale composite structures were proved.

Keywords: composite materials, low velocity impact, FEA, dynamic behavior, progressive damage modeling

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Authors: Oladipo Oluwaseun Peter

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Daily consumption of crude oil is alarming as a result of increasing demand for energy. Waste generation tends to rise with the level of economic advancement of a nation. Hence, this project work researches how wastes which could pose toxic if left unattended to can be processed through biodigestion in order to generate biofuel which could serve as a good substitute for petroleum, a non renewable energy source, so as to reduce over-dependence on petroleum and to prevent environmental pollution. Anaerobic digestion was carried out on organic wastes comprising brewery spent grains, rice husks and poultry droppings in a plastic biodigester of 1000 liters volume using the poultry droppings as a natural inoculums source. The feed composition in ratio 5:3:2, spent grain, rice husks and poultry droppings were mixed with water in the ratio 1:6. Thus, 600 Kg of water was used to prepare the slurry with 100 Kg of feed materials. A plastic biodigester was successfully constructed, and the problem of corrosion and rusting were completely overcome as a result of the use of non-corroding materials of construction. A reasonable quantity of biogas, 33.63m3, was generated over a period of 60 days of biodigestion. The bioslurry was processed through two different process routes; evaporation and filteration. Evaporation process of analysis shows high values of 0.64%, 2.11% and 0.034% for nitrogen, phosphorous and potassium respectively, while filteration process gives 00.61%, 1.93% and 0.026% for nitrogen, phosphorous and potassium respectively.

Keywords: biodigestion, biofuel, digestion, slurry, biogas

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Authors: Fatma M. Benrabha

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The aim of the study was to determine the type and pattern of antibiotic susceptibility of the pathogenic microorganisms causing chronic suppurative otitis media (CSOM), which could lead to better therapeutic decisions and consequently avoidance of appearance of resistance to specific antibiotics. Most frequently isolated agents were Pseudomonas aeruginosa 28.5%; followed by Staphylococcus aureus 18.2%; proteus mirabilis 13.9%; Providencia stuartti 6.7%; Bacteroides melaninogenicus, Aspergillus sp., candida sp., 4.2% each; and other microorganisms were represented in 3-0.2%. Drug sensitivities pattern of Pseudomonas aeruginosa showed that ciprofloxacin was active against the majority of isolates (93.9%) followed by ceftazidime 86.2%, amikacin 76.2% and gentamicin 40.8%. However, Staphylococcus aureus isolates were resistant to penicillin 72.7%, erythromycin 28.6%, cephalothin 18.2%, cloxacillin 8.3% and ciprofloxacin was active against 96.2% of isolates. The resistance pattern of proteus mirabilis were 55.6% to ampicillin, 47.1% to carbencillin, 29.4% to cephalothin, 14.3% to gentamicin and 4.8% to amikacin while 100% were sensitive to ciprofloxacin. We conclude that ciprofloxacin is the best drug of choice in treatment of CSOM caused by the common microorganisms.

Keywords: otitis media, chronic suppurative otitis media (CSOM), microorganism, drug sensitivity

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Authors: Amr Mohamadien, Ali Imanpour, Sylvester Agbo, Nader Yoosef-Ghodsi, Samer Adeeb

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The fracture toughness resistance curve (e.g., J-R curve and crack tip opening displacement (CTOD) or δ-R curve) is important in facilitating strain-based design and integrity assessment of oil and gas pipelines. This paper aims to present laboratory experimental data to characterize the fracture behavior of pipeline steel. The influential parameters associated with the fracture of API 5L X52 pipeline steel, including different initial crack sizes, were experimentally investigated for a single notch edge bend (SENB). A total of 9 small-scale specimens with different crack length to specimen depth ratios were conducted and tested using single edge notch bending (SENB). ASTM E1820 and BS7448 provide testing procedures to construct the fracture resistance curve (Load-CTOD, CTOD-R, or J-R) from test results. However, these procedures are limited by standard specimens’ dimensions, displacement gauges, and calibration curves. To overcome these limitations, this paper presents the use of small-scale specimens and a 3D-digital image correlation (DIC) system to extract the parameters required for fracture toughness estimation. Fracture resistance curve parameters in terms of crack mouth open displacement (CMOD), crack tip opening displacement (CTOD), and crack growth length (∆a) were carried out from test results by utilizing the DIC system, and an improved regression fitting resistance function (CTOD Vs. crack growth), or (J-integral Vs. crack growth) that is dependent on a variety of initial crack sizes was constructed and presented. The obtained results were compared to the available results of the classical physical measurement techniques, and acceptable matchings were observed. Moreover, a case study was implemented to estimate the maximum strain value that initiates the stable crack growth. This might be of interest to developing more accurate strain-based damage models. The results of laboratory testing in this study offer a valuable database to develop and validate damage models that are able to predict crack propagation of pipeline steel, accounting for the influential parameters associated with fracture toughness.

Keywords: fracture toughness, crack propagation in pipeline steels, CTOD-R, strain-based damage model

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Authors: Raul Chavez Jr.

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Green roof's body of knowledge appears to be in its infancy stage in the Philippines. To contribute to its development, this study intends to answer the question: Does the existing green roof in Metro Manila perform well in providing thermal comfort and satisfaction to users? Relatively, this study focuses on thermal sensation and satisfaction of users, surface temperature comparison, weather data comparison of the site (Sky Garden) and local weather station (PAG-ASA), and its thermal resistance capacity. Initially, the researcher conducted a point-in-time survey in parallel with weather data gathering from PAG-ASA and Sky Garden. In line with these, ambient and surface temperature are conducted through the use of a digital anemometer, with humidity and temperature, and non-contact infrared thermometer respectively. Furthermore, to determine the Sky Garden's overall thermal resistance, materials found on site were identified and tabulated based on specified locations. It revealed that the Sky Garden can be considered comfortable based from PMV-PPD Model of ASHRAE Standard 55 having similar results from thermal comfort and thermal satisfaction survey, which is contrary to the actual condition of the Sky Garden by means of a psychrometric chart which falls beyond the contextualized comfort zone. In addition, ground floor benefited the most in terms of lower average ambient temperature and humidity compared to the Sky Garden. Lastly, surface temperature data indicates that the green roof portion obtained the highest average temperature yet performed well in terms of heat resistance compared to other locations. These results provided the researcher valuable baseline information of the actual performance of a certain green roof in Metro Manila that could be vital in locally enhancing the system even further and for future studies.

Keywords: Green Roof, Thermal Analysis, Thermal Comfort, Thermal Performance

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Authors: Opemiposi Adegbulu

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Conflicts of interest is an elusive, diverse and engaging subject, a cross-cutting problem of governance; all levels of governance, ranging from local to global, public to corporate or financial sectors. In all these areas, its mismanagement could lead to the distortion of decision-making processes, corrosion of trust and the weakening of administration. According to Professor Peters, an expert in the area, conflict of interest, a problem at the root of many scandals has “become a pervasive ethical concern in our professional, organisational, and political life”. Conflicts of interest corrode trust, and like in the public sector, trust is mandatory for the market, consumers/clients, shareholders and other stakeholders in the private sector. However, conflicts of interest in the private sector are distinct and must be treated in like manner when regulatory efforts are made to address them. The research looks at identifying conflicts of interest in the private sector and differentiating them from those in the public sector. The public interest is submitted as a criterion which allows for such differentiation. This is significant because it would for the use of tailor-made or sector-specific approaches to addressing this complex issue. This is conducted through extensive review of literature and theories on the definition of conflicts of interest. This study will employ theoretical, doctrinal and comparative methods. The nature of conflicts of interest in the private sector will be explored, through an analysis of the public sector where the notion of conflicts of interest appears more clearly identified, reasons, why they are of business ethics concern, will be advanced, and then, once again, looking at public sector solutions and other solutions, the study will identify ways of mitigating and managing conflicts in the private sector. An exploration of public sector conflicts of interest and solutions will be carried out because the typologies of conflicts of interest in both sectors appear very similar at the core and thus, lessons can be learnt with regards to the management of these issues in the private sector. Conflicts of interest corrode trust, and like in the public sector, trust is mandatory for the market, consumers/clients, shareholders and other stakeholders in the private sector. This research will then focus on some specific challenges to understanding and identifying conflicts of interest in the private sector; origin, diverging theories, the psychological barrier to the definition, similarities with public sector conflicts of interest due to the notions of corrosion of trust, ‘being in a particular kind of situation,’ etc. The notion of public interest will be submitted as a key element at the heart of the distinction between public sector and private sector conflicts of interests. It will then be proposed that the appreciation of the notion of conflicts of interest differ according to sector, country to country, based on the public interest test, using the United Kingdom (UK), the United States of America (US), France and the Philippines as illustrations.

Keywords: conflicts of interest, corporate governance, global governance, public interest

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Authors: Alfred Hasanaj , Ardit Gjeta, Miranda Kullolli

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The approach in analyzing defects on different pipe lines is conducted through Failure Assessment Diagram (FAD). These methods of analyses have further extended in recent years. This approach is used to identify and stress out a solution for the defects which randomly occur with gas pipes such are corrosion defects, gauge defects, and combination of defects where gauge and dents are included. Few of the defects are to be analyzed in this paper where our main focus will be the fracture of cast Iron pipes, elastic-plastic failure and plastic collapse of X52 steel pipes for gas transport. We need to conduct a calculation of probability of the defects in order to predict and avoid such costly defects.

Keywords: defects, failure assessment diagrams, steel pipes, safety factor

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Authors: Prasanjit Das, M .M. K. Khan, M. G. Rasul, Jie Wu, I. Youn

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Crystallisation scale occurs when dissolved minerals precipitate from an aqueous solution. To investigate the crystallisation scale growth of normal solubility salt, a lab-scale agitation tank with and without baffles were used as a benchmark using potassium nitrate as the test fluid. Potassium nitrate (KNO3) solution in this test leads to crystallisation scale on heat transfer surfaces. This experimental investigation has focused on the effect of surface crystallisation of potassium nitrate on the low-temperature heat exchange surfaces on the wall of the agitation tank. The impeller agitation rate affects the scaling rate at the low-temperature agitation wall and it shows a decreasing scaling rate with an increasing agitation rate. It was observed that there was a significant variation of heat transfer coefficients and scaling resistance coefficients with different agitation rate as well as with varying impeller size, tank with and without baffles and solution concentration.

Keywords: crystallisation, heat transfer coefficient, scale, resistance

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Authors: Majed Zobairy, Fardin Kalvandi, Kamal Azizbaigi

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This research was carried out for evaluation of elastic, plyometric and resistance training on selected anaerobic factors in men volleyball players. For these reason 30 elite volleyball players of Sanandaj city randomly divided into 3 groups as follow: elastic training, plyometric training and resistance training. Pre-exercise tests which include vertical jumping, 50 yard speed running and scat test were done and data were recorded. Specific exercise protocol regimen was done for each group and then post-exercise tests again were done. Data analysis showed that there were significant increases in exercise test in each group. One way ANOVA analysis showed that increases in speed records in elastic group were significantly higher than the other groups (p<0/05),based on research data it seems that elastic training can be a useful method and new approach in improving functional test and training regimen.

Keywords: elastic training, plyometric training, strength training, anaerobic power

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Authors: Rosa Tsegaye Aga, Xuan Jiang, Pavel Vazquez Faci, Siqing Liu, Simon Rayner, Endalkachew Alemu, Markos Abebe

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Tuberculosis (TB) is a major cause of disease globally. In most cases, TB is treatable and curable, but only with the proper treatment. There is a time when drug-resistant TB occurs when bacteria become resistant to the drugs that are used to treat TB. Current strategies to identify drug-resistant TB bacteria are laboratory-based, and it takes a longer time to identify the drug-resistant bacteria and treat the patient accordingly. But machine learning (ML) and data science approaches can offer new approaches to the problem. In this study, we propose to develop an ML-based model to predict the antibiotic resistance phenotypes of TB isolates in minutes and give the right treatment to the patient immediately. The study has been using the whole genome sequence (WGS) of TB isolates as training data that have been extracted from the NCBI repository and contain different countries’ samples to build the ML models. The reason that different countries’ samples have been included is to generalize the large group of TB isolates from different regions in the world. This supports the model to train different behaviors of the TB bacteria and makes the model robust. The model training has been considering three pieces of information that have been extracted from the WGS data to train the model. These are all variants that have been found within the candidate genes (F1), predetermined resistance-associated variants (F2), and only resistance-associated gene information for the particular drug. Two major datasets have been constructed using these three information. F1 and F2 information have been considered as two independent datasets, and the third information is used as a class to label the two datasets. Five machine learning algorithms have been considered to train the model. These are Support Vector Machine (SVM), Random forest (RF), Logistic regression (LR), Gradient Boosting, and Ada boost algorithms. The models have been trained on the datasets F1, F2, and F1F2 that is the F1 and the F2 dataset merged. Additionally, an ensemble approach has been used to train the model. The ensemble approach has been considered to run F1 and F2 datasets on gradient boosting algorithm and use the output as one dataset that is called F1F2 ensemble dataset and train a model using this dataset on the five algorithms. As the experiment shows, the ensemble approach model that has been trained on the Gradient Boosting algorithm outperformed the rest of the models. In conclusion, this study suggests the ensemble approach, that is, the RF + Gradient boosting model, to predict the antibiotic resistance phenotypes of TB isolates by outperforming the rest of the models.

Keywords: machine learning, MTB, WGS, drug resistant TB

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Authors: Mattia Testuzza

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Public health is a social endeavour, which involves many different actors: from extremely stratified, structured health systems to unofficial networks of people and knowledge. Health and diseases are an intertwined individual and social experiences. Both patients and health workers navigate this public space through relations of trust. Trust in healthcare goes from the personal trust between a patient and her/his doctor to the trust of both the patient and the health worker in the medical knowledge and the healthcare system. Trust it is not a given, but it is continuously negotiated, given and gained. The key to understand these essential relations of trust in health is to recognise them as a social practice, which therefore implies agency and power. In these terms, health is constantly public and made public, as trust emerges as a meaningfully political phenomenon. Trust as a power relation can be observed at play in the implementation of public health policies such as the WHO’s Directly-Observed Theraphy Short-course (DOTS), and with the increasing concern for drug-resistance that tuberculosis pose, looking at the role of trust in the healthcare delivery system and implementation of public health policies becomes significantly relevant. The ethnographic fieldwork was carried out in four months through observation of the daily practices at the National Tuberculosis Center of Nepal, and semi-structured interviews with MultiDrug-Resistant Tuberculosis (MDR-TB) patients at different stages of the treatment, their relatives, MDR-TB specialised nurses, and doctors. Throughout the research, the role which trust plays in tuberculosis treatment emerged as one fundamental ax that cuts through all the different factors intertwined with drug-resistance development, unfolding a tension between the DOTS policy, which undermines trust, and the day-to-day healthcare relations and practices which cannot function without trust. Trust also stands out as a key component of the solutions to unforeseen issues which develop from the overall uncertainty of the context - for example, political instability and extreme poverty - in which tuberculosis treatment is carried out in Nepal.

Keywords: trust, tuberculosis, drug-resistance, politics of health

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Authors: Siavash Soltani Hemmat

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Although 21st-century humanity is at the height of technology and has stepped toward the endless boundaries of knowledge, there are still people in many parts of the world who are deprived of even the most fundamental freedoms. Whereas without freedom, no possible meaning can be imagined for human life, none of the human talents will have the chance to flourish, and that man will be reduced to the level of an animal, removing the obstacles to human freedom, especially from the viewpoint of thoughts, is of utmost importance, in which the liberal ideas of the modern centuries have played an incomparable role. The aim of the present study is to introduce and explain the liberal ideas in the modern centuries and their role in the expansion of human freedoms in order to weaken and discredit the ideological and intellectual barriers to restricting the freedom of individuals and to pave the way for the liberation of humanity. A descriptive method has been employed in order to achieve the objectives of the research. Besides, for data collection, a library method has been conducted. In this study, three ideological teachings of the social contract , resistance against unjust governance and natural law were recognized as the foundations of the realization of fundamental freedoms of the people in the modern centuries and their content was explained and examined.

Keywords: freedom, natural law, social contract, resistance

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Authors: M. Rouhani, F. C. N. Hong, Y. R. Jeng

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The tribological performance of DLC films is limited by graphitization at elevated temperatures. Despite of numerous studies on the thermal stability of DLC films, a comprehensive in-situ characterization at elevated temperature is still lacking. In this study, DLC films were deposited using filtered cathodic arc vacuum method. Thermal stability of the films was characterized in-situally using a synchronized technique integrating Raman spectroscopy and depth-sensing measurements. Tests were performed in a high temperature chamber coupled with feedback control to make it possible to study the temperature effects in the range of 21 – 450 ̊C. Co-located SPM and Raman microscopy maps at different temperature over a specific area on the surface of the film were prepared. The results show that the thermal stability of the DLC films depends on their sp3 content. Films with lower sp3 content endure graphitization during the temperature-course used in this study. The graphitization is accompanied with significant changes in surface roughness and Raman spectrum of the film. Surface roughness of the films start to change even before graphitization transformation could be detected using Raman spectroscopy. Depth-sensing tests (nanoindentation, nano-scratch and wear) endorse the surface roughness change seen before graphitization occurrence. This in-situ study showed that the surface of the films is more sensitive to temperature rise compared to the bulk. We presume the changes observed in films hardness, surface roughness and scratch resistance with temperature rise, before graphitization occurrence, is due to surface relaxation.

Keywords: DLC film, nanoindentation, Raman spectroscopy, thermal stability

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Authors: Gennaro Marino

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This paper concerns a case of a 10.75 inch diameter buried gas transmission line which was exposed to mine subsidence ground movements. The pipeline was buried about 4ft. below the surface with maximum operating pressure of 1440 psi. The mine subsidence movement was the result of long walling ore at a depth of approximately 1600 ft. As ore extraction progressed, the stress in the monitored pipeline worsened and was approaching unacceptable levels. The excessive pipe compression resulted when it was exposed to the compression zone of subsidence basin created by mining. The pipe stress reached a significant compressive level due to the extensive length of the pipe exposed to frictional ground-pipe slip resistance. The backfill ground movement slip resistance depends on normal stress around the pipe, the rate of slip, and the backfill characteristics. Normal stress depends on the burial depth of the backfill density and the lateral subsidence induced stress. The backfill in this site has a soil dry density of approximately 90 PCF. A suite of direct shear tests was conducted a residual friction angle of 36 was determined for the ambient backfill. These tests showed that the residual shearing resistance was reached within a fraction of an inch. The pipe was coated with fusion-bonded epoxy, so friction reduce factory of 0.6 can be considered. To relieve ground movement induced compressive stress, the line was uncovered. As more of the pipeline was exposed, the pipe abruptly bowed in the excavation. An analysis of this pipe formation which was performed is provided in this paper. Also discussed in this paper are ways to mitigate this pipe deformation or upheaval buckling from occurring. Keywords: Pipe Upheaval, Pipe Buckling, Ground subsidence, Buried Pipeline, Pipe Stress Mitigation.

Keywords: pipe upheaval, pipe buckling, ground subsidence, buried pipeline, pipe stress mitigation

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Authors: Kanika Arora, Madhu Bala

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The small intestine epithelium is highly sensitive and major targets of ionizing radiation. Radiation causes gastrointestinal toxicity either by direct deposition of energy or indirectly (inflammation or bystander effects) generating free radicals and reactive oxygen species. Oxidative stress generated as a result of radiation causes active inflammation within the intestinal mucosa leading to structural and functional impairment of gut epithelial barrier. As a result, there is a loss of tolerance to normal dietary antigens and commensal flora together with exaggerated response to pathogens. Dysbiosis may therefore thought to play a role in radiation enteropathy and can contribute towards radiation induced bowel toxicity. Lactobacilli residing in the gut shares a long conjoined evolutionary history with their hosts and by doing so these organisms have developed an intimate and complex symbiotic relationships. The objective behind this study was to look for the strains with varying resistance to ionizing radiation and to see whether the niche of the bacteria is playing any role in radiation resistance property of bacteria. In this study, we have isolated the Lactobacillus spp. from probiotic preparation and murine gastrointestinal tract, both of which were supposed to be the important source for its isolation. Biochemical characterization did not show a significant difference in the properties, while a significant preference was observed in carbohydrate utilization capacity by the isolates. Effect of ionizing radiations induced by Co60 gamma radiation (10 Gy) on lactobacilli cells was investigated. A cellular survival curve versus absorbed doses was determined. Radiation resistance studies showed that the response of isolates towards cobalt-60 gamma radiation differs from each other and significant decrease in survival was observed in a dose-dependent manner. Thus the present study revealed that the property of radioresistance in Lactobacillus depends upon the source from where they have been isolated.

Keywords: dysbiosis, lactobacillus, mitigation, radiation

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Authors: Viriyavudh Sim, Jung Kyu Choi, Yong Ju Kwak, Oh Hyeon Jeon, Woo Young Jung

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In this study, we investigated the buckling performance of basalt fiber reinforced polymer (BFRP) sandwich infill panels. Fiber Reinforced Polymer (FRP) is a major evolution for energy dissipation when used as infill material of frame structure, a basic Polymer Matrix Composite (PMC) infill wall system consists of two FRP laminates surrounding an infill of foam core. Furthermore, this type of component is for retrofitting and strengthening frame structure to withstand the seismic disaster. In-plane compression was considered in the numerical analysis with ABAQUS platform to determine the buckling failure load of BFRP infill panel system. The present result shows that the sandwich BFRP infill panel system has higher resistance to buckling failure than those of glass fiber reinforced polymer (GFRP) infill panel system, i.e. 16% increase in buckling resistance capacity.

Keywords: Basalt Fiber Reinforced Polymer (BFRP), buckling performance, FEM analysis, sandwich infill panel

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Authors: A. M. Pashayev, A. S. Samedov, T. B. Usubaliyev, N. Sh. Yusifov

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Different types of coating technologies are widely used for gas turbine blades. Thermal barrier coatings, consisting of ceramic top coat, thermally grown oxide and a metallic bond coat are used in applications for thermal protection of hot section components in gas turbine engines. Operational characteristics and longevity of high-temperature turbine blades substantially depend on a right choice of composition of the protective thermal barrier coatings. At a choice of composition of a coating and content of the basic elements it is necessary to consider following factors, as minimum distinctions of coefficients of thermal expansions of elements, level of working temperatures and composition of the oxidizing environment, defining the conditions for the formation of protective layers, intensity of diffusive processes and degradation speed of protective properties of elements, extent of influence on the fatigue durability of details during operation, using of elements with high characteristics of thermal stability and satisfactory resilience of gas corrosion, density, hardness, thermal conduction and other physical characteristics. Forecasting and a choice of a thermal barrier coating composition, all above factors at the same time cannot be considered, as some of these characteristics are defined by experimental studies. The implemented studies and investigations show that one of the main failures of coatings used on gas turbine blades is related to not fully taking the physical-chemical features of elements into consideration during the determination of the composition of alloys. It leads to the formation of more difficult spatial structure, composition which also changes chaotically in some interval of concentration that doesn't promote thermal and structural firmness of a coating. For the purpose of increasing the thermal and structural resistant of gas turbine blade coatings is offered a new approach to forecasting of composition on the basis of analysis of physical-chemical characteristics of alloys taking into account the size factor, electron configuration, type of crystal lattices and Darken-Gurry method. As a result, of calculations and experimental investigations is offered the new four-component metallic bond coat on the basis of chrome for the gas turbine blades.

Keywords: gas turbine blades, thermal barrier coating, metallic bond coat, strategic metals, physical-chemical features

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Authors: Sarika Gupta, Harshika Khanna, Ajay K Verma, Surya Kant

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Background: Drug-resistant tuberculosis (DR-TB) is a growing health challenge to global TB control efforts. Pediatric DR-TB is one of the neglected infectious diseases. In our previously published report, we have notified an increased prevalence of DR-TB in the pediatric population at a tertiary health care centre in North India which was estimated as 17.4%, 15.1%, 18.4%, and 20.3% in (%) in the year 2018, 2019, 2020, and 2021. Limited evidence exists about a pattern of drug resistance, side effect profile and programmatic outcomes of Paediatric DR-TB treatment. Therefore, this study was done to find out the pattern of resistance, side effect profile and treatment outcome. Methodology: This was a prospective cohort study conducted at the nodal drug-resistant tuberculosis centre of a tertiary care hospital in North India from January 2021 to December 2022. Subjects included children aged between 0-18 years of age with a diagnosis of DR-TB, on the basis of GeneXpert (rifampicin [RIF] resistance detected), line probe assay and drug sensitivity testing (DST) of M. tuberculosis (MTB) grown on a culture of body fluids. Children were classified as monoresistant TB, polyresistant TB (resistance to more than 1 first-line anti-TB drug, other than both INH and RIF), MDR-TB, pre-XDR-TB and XDR-TB, as per the WHO classification. All the patients were prescribed DR TB treatment as per the standard guidelines, either shorter oral DR-TB regimen or a longer all-oral MDR/XDR-TB regimen (age below five years needed modification). All the patients were followed up for side effects of treatment once per month. The patient outcomes were categorized as good outcomes if they had completed treatment and cured or were improving during the course of treatment, while bad outcomes included death or not improving during the course of treatment. Results: Of the 50 pediatric patients included in the study, 34 were females (66.7%) and 16 were male (31.4%). Around 33 patients (64.7%) were suffering from pulmonary TB, while 17 (33.3%) were suffering from extrapulmonary TB. The proportions of monoresistant TB, polyresistant TB, MDR-TB, pre-XDR-TB and XDR-TB were 2.0%, 0%, 50.0%, 30.0% and 18.0%, respectively. Good outcome was reported in 40 patients (80.0%). The 10 bad outcomes were 7 deaths (14%) and 3 (6.0%) children who were not improving. Adverse events (single or multiple) were reported in all the patients, most of which were mild in nature. The most common adverse events were metallic taste 16(31.4%), rash and allergic reaction 15(29.4%), nausea and vomiting 13(26.0%), arthralgia 11 (21.6%) and alopecia 11 (21.6%). Serious adverse event of QTc prolongation was reported in 4 cases (7.8%), but neither arrhythmias nor symptomatic cardiac side effects occurred. Vestibular toxicity was reported in 2(3.9%), and psychotic symptoms in 4(7.8%). Hepatotoxicity, hypothyroidism, peripheral neuropathy, gynaecomastia, and amenorrhea were reported in 2 (4.0%), 4 (7.8%), 2 (3.9%), 1(2.0%), and 2 (3.9%) respectively. None of the drugs needed to be withdrawn due to uncontrolled adverse events. Conclusion: Paediatric DR TB treatment achieved favorable outcomes in a large proportion of children. DR TB treatment regimen drugs were overall well tolerated in this cohort.

Keywords: pediatric, drug-resistant, tuberculosis, adverse events, treatment

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Authors: Musaab Salman Sultan

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The surface and bulk magnetization behavior of template released isolated ferromagnetic Ni₆₀Fe₄₀ nanowires of relatively thick diameters (~200 nm), deposited from a dilute suspension onto pre-patterned insulating chips have been investigated experimentally, using a highly sensitive Magneto-Optical Ker Effect (MOKE) magnetometry and Magneto-Resistance (MR) measurements, respectively. The MR data were consistent with the theoretical predictions of the anisotropic magneto-resistance (AMR) effect. The MR measurements, in all the angles of investigations, showed large features and a series of nonmonotonic "continuous small features" in the resistance profiles. The extracted switching fields from these features and from MOKE loops were compared with each other and with the switching fields reported in the literature that adopted the same analytical techniques on the similar compositions and dimensions of nanowires. A large difference between MOKE and MR measurments was noticed. The disparate between MOKE and MR results is attributed to the variance in the micro-magnetic structure of the surface and the bulk of such ferromagnetic nanowires. This result was ascertained using micro-magnetic simulations on an individual: cylindrical and rectangular cross sections NiFe nanowires, with the same diameter/thickness of the experimental wires, using the Object Oriented Micro-magnetic Framework (OOMMF) package where the simulated loops showed different switching events, indicating that such wires have different magnetic states in the reversal process and the micro-magnetic spin structures during switching behavior was complicated. These results further supported the difference between surface and bulk magnetization behavior in these nanowires. This work suggests that a combination of MOKE and MR measurements is required to fully understand the magnetization behavior of such relatively thick isolated cylindrical ferromagnetic nanowires.

Keywords: MOKE magnetometry, MR measurements, OOMMF package, micromagnetic simulations, ferromagnetic nanowires, surface magnetic properties

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Authors: Soam Prakash, Namita Soni

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The synthesis of metallic nanoparticles is an active area of academic and more significantly, applied research in nanotechnology. Currently, nanoparticle research is an area of intense scientific interest. Silver (Ag) and Gold (Au) nanoparticles (NPs) have been the focus of fungi and plant based syntheses. Silver and gold nanoparticles are nanoparticles of silver and gold. These particles are of between 1 nm and 100 nm in size. Silver and gold have been use in the wide variety of potential applications in biomedical, optical, electronic field, treatment of burns, wounds, and several bacterial infections. There is a crucial need to produce new insecticides due to resistance and high-cost of organic insecticides which are more environmentally-friendly, safe, and target-specific. Synthesizing nanoparticles using plants and microorganisms can eliminate this problem by making the nanoparticles more biocompatible. Here we reviewed the mosquitocidal and antimicrobials activity of silver and gold nanoparticles using fungi, plants as well as bacteria.

Keywords: nano gold, nano silver, Malaria, Chikengunia, dengue control

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Authors: Kazunori Nomura, Hiromichi Ogi, Masaumi Nakahara, Sou Watanabe, Atsuhiro Shibata

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Chemical Processing Facility of Japan Atomic Energy Agency is a basic research field for advanced back-end technology developments with using actual high-level radioactive materials such as irradiated fuels from the fast reactor, high-level liquid waste from reprocessing plant. In the nature of a research facility, various kinds of chemical reagents have been offered for fundamental tests. Most of them were treated properly and stored in the liquid waste vessel equipped in the facility, but some were not treated and remained at the experimental space as a kind of legacy waste. It is required to treat the waste in safety. On the other hand, we formulated the Medium- and Long-Term Management Plan of Japan Atomic Energy Agency Facilities. This comprehensive plan considers Chemical Processing Facility as one of the facilities to be decommissioned. Even if the plan is executed, treatment of the “legacy” waste beforehand must be a necessary step for decommissioning operation. Under this circumstance, we launched a collaborative research project called the STRAD project, which stands for Systematic Treatment of Radioactive liquid waste for Decommissioning, in order to develop the treatment processes for wastes of the nuclear research facility. In this project, decomposition methods of chemicals causing a troublesome phenomenon such as corrosion and explosion have been developed and there is a prospect of their decomposition in the facility by simple method. And solidification of aqueous or organic liquid wastes after the decomposition has been studied by adding cement or coagulants. Furthermore, we treated experimental tools of various materials with making an effort to stabilize and to compact them before the package into the waste container. It is expected to decrease the number of transportation of the solid waste and widen the operation space. Some achievements of these studies will be shown in this paper. The project is expected to contribute beneficial waste management outcome that can be shared world widely.

Keywords: chemical processing facility, medium- and long-term management plan of JAEA facilities, STRAD project, treatment of radioactive waste

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Authors: Siddhant Srivastav, Shilpa Singh, Sumanta Kumar Meher

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Innovative renewable energy sources for energy storage/conversion is the demand of the current scenario in electrochemical machinery. In this context, choosing suitable organic precipitants for tuning the crystal characteristics and microstructures is a challenge. On the same note, herein we report broccoli flower-like porous Mn3O4/NiSe2−MnSe2 composite synthesized using a simple two step hydrothermal synthesis procedure assisted by sluggish precipitating agent and an effective cappant followed by intermediated anion exchange. The as-synthesized material was exposed to physical and chemical measurements depicting poly-crystallinity, stronger bonding and broccoli flower-like porous arrangement. The material was assessed electrochemically by cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS) measurements. The Electrochemical studies reveal redox behavior, supercapacitive charge-discharge shape and extremely low charge transfer resistance. Further, the fabricated Mn3O4/NiSe2−MnSe2 composite based solid-state hybrid supercapacitor (Mn3O4/NiSe2−MnSe2 ||N-rGO) delivers excellent rate specific capacity, very low internal resistance, with energy density (~34 W h kg–1) of a typical rechargeable battery and power density (11995 W kg–1) of an ultra-supercapacitor. Consequently, it can be a favorable contender for supercapacitor applications for high performance energy storage utilizations. A definitive exhibition of the supercapacitor device is credited to electrolyte-ion buffering reservior alike behavior of broccoli flower like Mn3O4/NiSe2−MnSe2, enhanced by upgraded electronic and ionic conductivities of N- doped rGO (negative electrode) and PVA/KOH gel (electrolyte separator), respectively

Keywords: electrolyte-ion buffering reservoir, intermediated-anion exchange, solid-state hybrid supercapacitor, supercapacitive charge-dischargesupercapacitive charge-discharge

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Authors: Vaishnavi Patil, K. M. Kurundkar

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Electrical Drives play a vital role in industry development and applications. Drives have an inevitable part in the needs of various fields such as industry, commercial, and domestic applications. The development of material technology, Power Electronics devices, and accompanying applications led to the focus of industry and researchers on high-speed electrical drives. Numerous articles charted the applications of electrical machines and various converters for high-speed applications. The choice depends on the application under study. This paper goals to highlight high-speed applications, main challenges, and some applications of electrical drives in the field.

Keywords: high-speed, electrical machines, drives, applications

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Authors: Noha Al Majid, Said Mazer, Moulhime El Bekkali, Catherine Algani, Mahmoud Mehdi

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A low noise figure (NF) and high linearity V-band Low Noise Amplifier (LNA) is reported in this article. The LNA compromises a three-stage cascode configuration. This LNA will be used as a part of a WPAN (Wireless Personal Area Network) receiver in the millimeter-wave band at 60 GHz. It is designed according to the MMIC technology (Monolithic Microwave Integrated Circuit) in PH 15 process from UMS foundry and uses a 0.15 μm GaAs PHEMT (Pseudomorphic High Electron Mobility Transistor). The particularity of this LNA compared to other LNAs in literature is its very low noise figure which is equal to 1 dB and its high linearity (IIP3 is about 22 dB). The LNA consumes 0.24 Watts, achieving a high gain which is about 23 dB, an input return loss better than -10 dB and an output return loss better than -8 dB.

Keywords: low noise amplifier, V-band, MMIC technology, LNA, amplifier, cascode, pseudomorphic high electron mobility transistor (PHEMT), high linearity

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Authors: Sophio Kobauri, Tengiz Kantaria, Temur Kantaria, David Tugushi, Nina Kulikova, Ramaz Katsarava

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Nanosized environmentally responsive materials are of special interest for various applications, including targeted drug to a considerable potential for treatment of many human diseases. The important technological advantages of nanoparticles (NPs) usage as drug carriers (nanocontainers) are their high stability, high carrier capacity, feasibility of encapsulation of both hydrophilic or hydrophobic substances, as well as a high variety of possible administration routes, including oral application and inhalation. NPs can also be designed to allow controlled (sustained) drug release from the matrix. These properties of NPs enable improvement of drug bioavailability and might allow drug dosage decrease. The targeted and controlled administration of drugs using NPs might also help to overcome drug resistance, which is one of the major obstacles in the control of epidemics. Various degradable and non-degradable polymers of both natural and synthetic origin have been used for NPs construction. One of the most promising for the design of NPs are amino acid-based biodegradable polymers (AABBPs) which can clear from the body after the fulfillment of their function. The AABBPs are composed of naturally occurring and non-toxic building blocks such as α-amino acids, fatty diols and dicarboxylic acids. The particles designed from these polymers are expected to have an improved bioavailability along with a high biocompatibility. The present work deals with a systematic study of the preparation of NPs by cost-effective polymer deposition/solvent displacement method using AABBPs. The influence of the nature and concentration of surfactants, concentration of organic phase (polymer solution), and the ratio organic phase/inorganic (water) phase, as well as of some other factors on the size of the fabricated NPs have been studied. It was established that depending on the used conditions the NPs size could be tuned within 40-330 nm. As the next step of this research an evaluation of biocompatibility and bioavailability of the synthesized NPs has been performed, using two stable human cell culture lines – HeLa and A549. This part of study is still in progress now.

Keywords: amino acids, biodegradable polymers, nanoparticles (NPs), non-toxic building blocks

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Authors: A. T. Nakysh, A. S. Idrisov, S. A. Baidurin

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This work presents the results of a study the incidence of metabolic syndrome (MetS) in women with impaired reproductive function (IRF) according to the data of Astana, Kazakhstan. The anthropometric, biochemical and instrumental studies were conducted among 515 women, of which 53 patients with MetS according to IDF criteria, 2006, were selected. The frequency of occurrence of the IRF, due to MetS – 10.3% of cases according to the data of Astana. In women of childbearing age with IRF and the MetS, blood pressure (BP), indicators of carbohydrate and lipid metabolism were significantly higher and the level of high density lipoprotein (HDL) significantly lower compared to the same in women with the IRF without MetS. The hyperandrogenism, the hyperestrogenemia, the hyperprolactinemia and the hypoprogesteronemia were found in the patients with MetS and IRF, indicating the impact of MetS on the development of the polycystic ovary syndrome in 28% of cases and hyperplastic processes of the myometrium in 20% of cases.

Keywords: dyslipidemia, insulin resistance, metabolic syndrome, reproductive disorders, obesity

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Authors: Cassi Henderson, Lucia Corsini, Shiv Kapila, Egle Augustaityte, Tsemaye Uwejamomere Zinzan Gurney, Aleyna Yildirim

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Plastic pollution is a major threat to human and planetary health. In Low- and Middle-Income Countries, plastic waste poses a major problem for marginalized populations who lack access to formal waste management systems. This study explores the potential for converting waste plastic into construction blocks. It is the first study to analyze the use of polyethylene terephthalate (PET) as a binder in plastic-sand bricks. Unlike previous studies of plastic sand-bricks, this research tests the properties of bricks that were made using a low-cost kiln technology that was co-designed with a rural, coastal community in Kenya.  The mechanical strength, resistance to fire and water absorption properties of the bricks are tested in this study. The findings show that the bricks meet structural standards for mechanical performance, fire resistance and water absorption. It was found that 30:70 PET to sand demonstrated the best overall performance.

Keywords: recycling, PET, plastic, sustainable construction, sustainable development

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Authors: Gilbert Makanda, Roelf Sypkens

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In this study we investigated the relevance of high school mathematics in university education. The paper particularly focused on whether the concepts taught in high school are enough for engineering courses at diploma level. The study identified particular concepts that are required in engineering courses whether they were adequately covered in high school. A questionnaire was used to investigate whether relevant topics were covered in high school. The respondents were 228 first year students at the Central University of Technology in the Faculty of Engineering and Information Technology. The study indicates that there are some topics such as integration, complex numbers and matrices that are not done at high schools and are required in engineering courses at university. It is further observed that some students did not cover the topics that are in the current syllabus. Female students enter the university less prepared than their male counterparts. More than 30% of the respondents in this study felt that high school mathematics was not useful for them to be able to do engineering courses.

Keywords: high school mathematics, university education, SPSS package, students' perceptions

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Authors: V. Pérez-Herranz, M. Pinel, E. M. Ortega, M. García-Gabaldón

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In the present work, Electrochemical Impedance Spectrocopy (EIS) is applied to study the transport of different metal cations through a cation-exchange membrane. This technique enables the identification of the ionic-transport characteristics and to distinguish between different transport mechanisms occurring at different current density ranges. The impedance spectra are dependent on the applied dc current density, on the type of cation and on the concentration. When the applied dc current density increases, the diameter of the impedance spectra loops increases because all the components of membrane system resistance increase. The diameter of the impedance plots decreases in the order of Na(I), Ni(II) and Cr(III) due to the increased interactions between the negatively charged sulfonic groups of the membrane and the cations with greater charge. Nyquist plots are shifted towards lower values of the real impedance, and its diameter decreases with the increase of concentration due to the decrease of the solution resistance.

Keywords: ion-exchange membranes, Electrochemical Impedance Spectrocopy, multivalent metal cations, membrane system

Procedia PDF Downloads 524