Search results for: surfactant-assisted ball milling

Authors: Slim Amami

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A model is developed to prevent the risks related to climate conditions in the agricultural sector. It will determine the yearly optimum premium to be paid by a farmer in order to reach his required turnover. The model is mainly based on both climatic stability and 'soft' responses of usually grown species to average climate variations at the same place and inside a safety ball which can be determined from past meteorological data. This allows the use of linear regression expression for dependence of production result in terms of driving meteorological parameters, main ones of which are daily average sunlight, rainfall and temperature. By a simple best parameter fit from the expert table drawn with professionals, optimal representation of yearly production is deduced from records of previous years, and yearly payback is evaluated from minimum yearly produced turnover. Optimal premium is then deduced, and gives the producer a useful bound for negotiating an offer by insurance companies to effectively protect their harvest. The application to wheat production in the French Oise department illustrates the reliability of the present model with as low as 6% difference between predicted and real data. The model can be adapted to almost every agricultural field by changing state parameters and calibrating their associated coefficients.

Keywords: agriculture, database, meteorological factors, production model, optimal price

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Authors: Elmira Ghanbari, Jan Van Esch, Stephen J. Picken, Sahil Aggarwal

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Organogels are formed by the assembly of low molecular weight gelators (LMWG) into fibrous structures. The assembly of these molecules into crystalline fibrous structures occurs as a result of reversible interactions such as π-stacking, hydrogen-bonding, and van der Waals interactions. Bisamide organogelators with two amide groups have been used as one of LMWGs which show efficient assembly behavior via hydrogen bonding for network formation, the formation of a crystalline network for solvent entrapment. In this study, different bisamide gelators with different lengths of alkyl chains have been added to the bisamide parent gels. The effect of the addition of bisamide additives on the gelation of bisamide gels is described. Investigation of the thermal properties of the gels by differential scanning calorimetry and dropping ball techniques indicated that the bisamide gels can be formed by the addition of a high concentration of the second bisamide components. The microstructure of the gels with different gelator components has been visualized with scanning electron microscopy (SEM) which has shown systematic woven, platelet-like, and a combination of those morphologies for different gels. Examining the addition of a range of bisamide additives with different structural characteristics than the parent bisamide gels has confirmed the effect of the molecular structure on the morphology of the bisamide gels and their final properties.

Keywords: bisamide organogelator additives, gel morphology, gel properties, self-assembly

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Authors: A. Tarantino, F. Lops, G. Disciglio, E. Tarantino

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Apulia region (southern Italy) is excellent for heavy production of apricot (Prunus armeniaca L.). Fruit quality is a combination of physical, chemical and nutritional characteristics. The present experiment was laid in the commercial orchard in Cerignola (Foggia district, Apulia region, 41°15’49’’N; 15°53’59’’E; 126 a.s.l.) during the 2014-2015 season. The experiment consisted of the use of three biostimulant treatments (Hendophyt®, Ergostim® and Radicon®) compared with untreated control on ‘Farbaly’ apricot cultivar, in order to evaluate the vegeto-productive and fruit qualitative attributes. Foliar spray of biostimulants was applied at different times during the growth season (at red ball, fruit setting and fruit development stages). Experimental data showed some specific differences among the biostimulant treatments, which fruit set, growth and productivity were affected. Moderate influences were found regarding the qualitative attributes of fruits. The soluble solid content was positively affected by Hendophyt® treatment. Antioxidant capacity was significantly higher in Hendophyt® and Radicon® treatments respect to the untreated control.

Keywords: Prunus Armeniaca L., biostimulants, fruit set, fruit quality

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Authors: Mehmet Fahri Sarac, Gokcen Akgun

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Ti–6Al–4V alloys are widely used in biomedical industries because of its attractive mechanical and physicochemical properties. However, they have poor wear resistance. High velocity oxygen fuel (HVOF) coatings were investigated as a way to improve the wear resistance of this alloy. In this paper, different mass ratio of Al₂O₃-TiO₂ powders (60/40, 87/13 and 97/3) was employed to enhance the tribological properties of Ti–6Al–4V. The tribological behavior was investigated by wear tests using ball-on-disc and pin-on-disc tribometer. The microstructures of the contact surfaces were determined by a scanning electron microscopy before and after the test to study the wear mechanism. Uncoated and coated surfaces after wear test are also subjected to micro-hardness tests. The tribological test results showed that the microhardness, friction and wear resistance of coated Ti-6Al-4V alloys increases by increasing TiO₂ content in the powder composite when other experimental conditions were constant. Finally, Al₂O₃-TiO₂ powder composites for the investigated conditions, both coating samples had satisfactory values of friction and wear resistance, and they could be suitable candidates for Ti–6Al–4V material.

Keywords: HVOF (High Velocity Oxygen Fuel), Al₂O₃-TiO₂, Ti-6Al-4V, tribology

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Authors: Asma Salman, Brian Gabbitas, Peng Cao, Deliang Zhang

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The performance of a coating is strongly dependent upon its microstructure, which in turn is dependent on the characteristics of the feedstock powder. This study involves the evaluation and performance of a titanium-based composite coating produced by the HVOF (high-velocity oxygen fuel) spraying method. The feedstock for making the composite coating was produced using high energy mechanical milling of TiO2 and Al powders followed by a combustion reaction. The characteristics of the feedstock powder were improved by treating it with an organic binder. Two types of coatings were produced using treated and untreated feedstock powders. The microstructures and characteristics of both types of coatings were studied, and their thermal shock resistance was accessed by dipping into molten aluminum. The results of this study showed that feedstock treatment did not have a significant effect on the microstructure of the coatings. However, it did affect the uniformity, thickness and surface roughness of the coating on the steel substrate. A coating produced by an untreated feedstock showed better thermal shock resistance in molten aluminum compared with the one produced by PVA (polyvinyl alcohol) treatment.

Keywords: coating, feedstock, powder processing, thermal shock resistance, thermally spraying

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Authors: Wiem Zemzem, Moncef Tagina

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In this work, we are addressing the problem of an autonomous mobile robot navigating in a large, unknown and dynamic environment using reinforcement learning abilities. This problem is principally related to the exploration/exploitation dilemma, especially the need to find a solution letting the robot detect the environmental change and also learn in order to adapt to the new environmental form without ignoring knowledge already acquired. Firstly, a new action selection strategy, called ε-greedy-MPA (the ε-greedy policy favoring the most promising actions) is proposed. Unlike existing exploration/exploitation policies (EEPs) such as ε-greedy and Boltzmann, the new EEP doesn’t only rely on the information of the actual state but also uses those of the eventual next states. Secondly, as the environment is large, an exploration favoring least recently visited states is added to the proposed EEP in order to accelerate learning. Finally, various simulations with ball-catching problem have been conducted to evaluate the ε-greedy-MPA policy. The results of simulated experiments show that combining this policy with the Qlearning method is more effective and efficient compared with the ε-greedy policy in stationary environments and the utility-based reinforcement learning approach in non stationary environments.

Keywords: autonomous mobile robot, exploration/ exploitation policy, large, dynamic environment, reinforcement learning

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Authors: Imen Abid, Rachel Calvet, Michel Baltas

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Flavonoids are secondary metabolites that belong to a polyphenolic class, present in fruits and vegetables, playing a significant role in biological systems. The structural variations of these flavonoids are associated with many biological and pharmacological activities (antioxidant, anti-inflammatory, anticancer, antibacterial, antifungal, antiviral, and antimalarial). Given their importance in plants and health-promoting roles in humans, significant efforts have been devoted towards their isolation of flavonoids and chemical elaboration (organic synthesis). But with the increasing public concern over environmental degradation and future resources, it is of great importance for chemists to come up with different approaches, less hazardous to human health and the environment. Being employed in large amounts, the solvents used in organic synthesis are high on the list of environmental pollutants. To overcome these problems, our approach is to develop unconventional processes involving solvent-free conditions. The application of mechanical forces to solvent-free or solvent-less reaction mixtures through the use of ball mills offers many advantages over traditional solvent-based strategies. It is one of the unconventional activation methods, which makes it possible to overcome the use of solvents, in the context of green chemistry and more respectful of the environment.

Keywords: organic synthesis, green chemistry, mecanochemistry, pharmaceutical molecules

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Authors: Ashbeelah Shafaqat Ali

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Pakistan is a country where the transgender community has not been accepted as a third gender yet, but in recent years Pakistani drama industry has taken an initiative to include Transgender characters in the past few years. This research based on qualitative method i.e. content analysis and in-depth interviews investigates the depiction of transgender community in Pakistani television dramas. This study examined two dramas i.e.' Khuda Mera Bhi Hai' and 'Alif Allah Aur Insaan' to analyze the representation of transgender community whereas, in-depth Interviews from 15 transgender people lived in Lahore to observe their opinion regarding their representation in Pakistani television dramas. Snow-ball sampling technique was used for conducting interviews from the transgender community. The results concluded that transgender community did not get equal coverage in Pakistani television dramas but inclusion as characters were observed. This study is helpful in providing a base for observing role of Pakistani television dramas in the development of transgender identity. The major finding revealed is that the inclusion of representation of transgender community in Pakistani television dramas has indicated a successful development towards positive representation. Although, it was suggested by the interviewers that before producing a television drama, appropriate research must be conducted to depict the real life story, problems and struggles of the transgender community. Furthermore, it was analyzed that only fair and equal representation of transgender community by Pakistani drama industry can be beneficial in promoting the third gender rights in the society.

Keywords: Pakistani dramas, portrayal, stereotypes, transgender

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Authors: Srinivasan Chandrasekaran, R. Nagavinothini

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Offshore platforms for ultra-deep waters are form-dominant by design; hybrid systems with large flexibility in horizontal plane and high rigidity in vertical plane are preferred due to functional complexities. Offshore triceratops is relatively a new-generation offshore platform, whose deck is partially isolated from the supporting buoyant legs by ball joints. They allow transfer of partial displacements of buoyant legs to the deck but restrain transfer of rotational response. Buoyant legs are in turn taut-moored to the sea bed using pre-tension tethers. Present study will discuss detailed dynamic analysis and preliminary design of the chosen geometric, which is necessary as a proof of validation for such design applications. A detailed numeric analysis of triceratops at 2400 m water depth under random waves is presented. Preliminary design confirms member-level design requirements under various modes of failure. Tether configuration, proposed in the study confirms no pull-out of tethers as stress variation is comparatively lesser than the yield value. Presented study shall aid offshore engineers and contractors to understand suitability of triceratops, in terms of design and dynamic response behaviour.

Keywords: offshore structures, triceratops, random waves, buoyant legs, preliminary design, dynamic analysis

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Authors: Emie A. Salamangkit-Mirasol, Rinlee Butch M. Cervera

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Rice hull or rice husk (RH) is an agricultural waste obtained from milling rice grains. Since RH has no commercial value and is difficult to use in agriculture, its volume is often reduced through open field burning which is an environmental hazard. In this study, amorphous nanosilica from Philippine waste RH was prepared via acid precipitation method. The synthesized samples were fully characterized for its microstructural properties. X-ray diffraction pattern reveals that the structure of the prepared sample is amorphous in nature while Fourier transform infrared spectrum showed the different vibration bands of the synthesized sample. Scanning electron microscopy (SEM) and particle size analysis (PSA) confirmed the presence of agglomerated silica particles. On the other hand, transmission electron microscopy (TEM) revealed an amorphous sample with grain sizes of about 5 to 20 nanometer range and has about 95 % purity according to EDS analyses. The elemental mapping also suggests that leaching of rice hull ash effectively removed the metallic impurity such as potassium element in the material. Hence, amorphous nanosilica was successfully prepared via a low-cost acid precipitation method from Philippine waste rice hull. In addition, initial electrode performance of the synthesized samples as an anode material in Lithium Battery have been investigated.

Keywords: agricultural waste, anode material, nanosilica, rice hull

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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: Khiaira S. Hassan, Abbas S. Alwan, Muna K. Abbass

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This research aims to study the effect of the liquid nitriding and shot peening on the hardness, surface roughness, residual stress, microstructure and corrosion behavior of austenite stainless steel 316 L. Chemical surface heat treatment by liquid nitriding process was carried out at 500 °C for 1 h and followed by shot peening with using ball steel diameter of 1.25 mm in different exposure time of 10 and 20 min. Electrochemical corrosion test was applied in sea water (3.5% NaCl solution) by using potentostat instrument. The results showed that the nitride layer consists of a compound layer (white layer) and diffusion zone immediately below the alloy layer. It has been found that the mechanical treatment (shot peening) has led to the formation of compressive residual stresses in layer surface that increased the hardness of stainless steel surface. All surface treatment (nitriding and shot peening) processes have led to the formation of carbide of CrN in hard surface layer. It was shown that both processes caused an increase in surface hardness and roughness which increases with shot peening time. Also, the corrosion results showed that the liquid nitriding and shot peening processes increase the corrosion rate to values more than that of not treated stainless steel.

Keywords: stainless steel 316L, shot peening, nitriding, corrosion, hardness

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Authors: Wasiu Oyeleke Oyediran

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Maize is a common staple food for human consumption and livestock feeds. It provides employment and means of livelihood for women in both rural areas and urban centres in Nigeria. However, the entrepreneurial skills of women engaged in its processing and value addition has not been fully enhanced. This study was therefore carried out to investigate rural women entrepreneurial skills in maize processing and value addition in Ogun State, Nigeria. Snow ball sampling technique was used in the selection of 70 respondents for this study. Data were analyzed with descriptive statistics and chi-square. Results revealed that majority (50.0%) of the respondents were 31 - 40 years of age and 60% of the respondents had spent 6 – 10 years in maize processing. The respondents have great entrepreneurial skills in popcorn (85.7%), corn cake (80.0%), corn balls (64.3%) and kokoro (52.9%) making. The majority of the respondents accessed information and entrepreneurial skills through fellow processors (88.6%) and friends and neighbours (62.9%). Major constraints to maize processing and value addition were scarcity of raw materials during off season periods (95.7%), ineffective preservation methods (88.6%), lack of modern processing equipment (82.9%), and high cost of processing machines (72.9%). Result of chi-square showed that there is significant association between personal characteristics of the respondents and entrepreneurial skills of the women at p < 0.05. It is hereby recommended that subsidized processing equipment should be made available to the maize processors in the study area by the government and NGOs.

Keywords: women, entreprenuerial skills, maize prcessing, value addition

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Authors: Qian Qiao, Tongjin Xiao, Hongtu He, Jiaxin Yu

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This study is focused on the synergetic effects of water and sulfur dioxide treatments (SO₂ treatments) on the mechanochemical wear of SLS glass. It is found that the wear behavior of SLS glass in humid air is very sensitive to the water and SO₂ treatment environments based on the wear test using a ball-on-flat reciprocation tribometer. When SLS glass is treated with SO₂-without, the presence of water, the wear resistance of SLS glass in humid air becomes significantly higher compared to the pristine glass. However, when SLS glass is treated with SO₂ with the presence of water, the wear resistance of SLS glass decreases remarkably with increasing in the relative humidity (RH) from 0% to 90%. Further analyses indicate that when sodium ions are leached out of SLS glass surface via the water and SO₂ treatments, the mechanochemical properties of SLS glass surface become different depending on the RH. At lower humidity, the nano hardness of the Na⁺-leached surface is higher, and it can contribute to the enhanced wear resistance of SLS glass. In contrast, at higher humidity conditions, the SLS glass surface is more hydrophilic, and substantial wear debris can be found inside the wear track of SLS glass. Those phenomena suggest that adhesive wear and abrasive wear dominate the wear mechanism of SLS glass in humid air, causing the decreased wear resistance of SLS glass with increasing the RH. These results may not only provide a deep understanding of the wear mechanism of SLS glass but also helpful for operation process of functional and engineering glasses.

Keywords: soda lime silicate glass, wear, water, SO₂

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Authors: M. A. Moghaddas, M. Short, N. Wiley, A. Y. Yi, K. F. Graff

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The application of ultrasonic vibrations to machining processes has a long history, ranging from slurry-based systems able to drill brittle materials, to more recent developments involving low power ultrasonics for high precision machining, with many of these at the research and laboratory stages. The focus of this development is the application of high levels of ultrasonic power (1,000’s of watts) to standard, heavy duty machine tools – drilling being the immediate focus, with developments in milling in progress – with the objective of dramatically increasing system productivity through faster feed rates, this benefit arising from the thrust force reductions obtained by power ultrasonic vibrations. The presentation will describe development of an advanced drilling system based on a special, acoustically designed, rugged drill module capable of functioning under heavy duty production conditions, and making use of standard tool holder means, and able to obtain thrust force reductions while maintaining or improving surface finish and drilling accuracy. The characterization of the system performance will be described, and results obtained in drilling several materials (Aluminum, Stainless steel, Titanium) presented.

Keywords: dimensional accuracy, machine tool, productivity, surface roughness, thrust force, ultrasonic vibrations, ultrasonic-assisted drilling

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Authors: J. M. Hung, J. S. Chan, M. I. Kuo, D. S. Chan, C. P. Lu

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Wheat germ is a by-product obtained from wheat milling and it contains highly concentrated nutrients. Due to highly lipase and lipoxygenase activities, wheat germ products can easily turn into rancid flavor and cause a short life. The objective of this study is to control moisture content and retard lipid hydrolysis by fluidized-bed drying. The raw wheat germ of 2 kg was dried with a vertical batch fluidized bed with the following varying conditions, inlet air temperature of 50, 80 and 120°C, inlet air velocity of 3.62 m/s. The experiment was designed to obtain a final product at around 40°C with water activity of 0.3 ± 0.1. Changes in the moisture content, water activity, enzyme activity of dried wheat germ during storage were measured. Results showed the fluidized-bed drying was found to reduce moisture content, water activity and lipase activity of raw wheat germ. After drying wheat germ, moisture content and water activity were between 5.8% to 7.2% and 0.28 to 0.40 respectively during 12 weeks of storage. The variation range of water activity indicated to retard lipid oxidation. All drying treatments displayed inactivation of lipase, except for drying condition of 50°C which showed relative high enzyme activity. During storage, lipase activity increased slowly during the first 6 weeks of storage and reached a plateau for another 6 weeks. As a result, using a fluidized-bed dryer was found to be effective drying technique in improving storage stability of wheat germ.

Keywords: wheat germ, fluidized-bed dryer, storage, lipase, stability

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Authors: Areej Almalkawi, Sameer Hamadna, Parviz Soroushian, Nalin Darsana

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The work on indigenous binders in this paper focused on the following indigenous raw materials: red clay, red lava and pumice (as primary aluminosilicate precursors), wood ash and gypsum (as supplementary minerals), and sodium sulfate and lime (as alkali activators). The experimental methods used for evaluation of these indigenous raw materials included laser granulometry, x-ray fluorescence (XRF) spectroscopy, and chemical reactivity. Formulations were devised for transforming these raw materials into alkali aluminosilicate-based hydraulic cements. These formulations were processed into hydraulic cements via simple heating and milling actions to render thermal activation, mechanochemical and size reduction effects. The resulting hydraulic cements were subjected to laser granulometry, heat of hydration and reactivity tests. These cements were also used to prepare mortar mixtures, which were evaluated via performance of compressive strength tests. The measured values of strength were correlated with the reactivity, size distribution and microstructural features of raw materials. Some of the indigenous hydraulic cements produced in this reporting period yielded viable levels of compressive strength. The correlation trends established in this work are being evaluated for development of simple and thorough methods of qualifying indigenous raw materials for use in production of indigenous hydraulic cements.

Keywords: one-part geopolymer cement, aluminosilicate precursors, thermal activation, mechanochemical

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Authors: Gheimati Salar

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The objective of conducting this research was to study the influence of plyometric exercises on the biomechanical selected factor of elite teen swimmers and compare the influence of plyometric exercises on the speed of front crawl and back crawl in empirical and control groups of teens. In order to conduct these study 30 swimmers with minimum of 3 years' experience who were 11 or 12 were randomly chosen and divided into 2 groups of 15. The first group was empirical and the second was control group. The speed of the swimmer was analyzed after 25 meters of swimming and their speed were recorded in the last. The researcher was standing stable at the beginning and then started the chronometer and stopped it at the end of the swimming. He repeated the record taking two times and then the average was taken. Before conducting plyometric exercises, a speed test was taken from both groups in both types of swimming. The duration of plyometric exercises was 8 weeks, every week 3 sessions and 24 sessions in total. The exercises in this study were focused on 3 parts of the body. Upper limb part, the lower part of the body and trunk area. Upper limb exercises consisted of four parts. The lower limb exercises consisted of 5 parts, and the trunk exercises consisted of four sections. A Medicine ball, cone and different weights were used in these exercises.

Keywords: plyometric, exercises, front crawl and back crawl, speed

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Authors: Hina Gul Rajpoot, Wazeer Hussain Solangi

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Experimental Design (DOE) economically maximizes information; we deliberately change one or more process variables (looms) in order to observe the effect the changes have on one or more response fabric properties. In DOE obtained data can be analyzed to yield valid and objective conclusions. An Experimental Design is lying out of a detailed experimental plan in advance and maximizes the amount of "information" that can be obtained for a given amount of experimental. Fabric of 36 inches having following weaves was used. 3/1 twill, warp cotton (10.5 den), weft Lycra (16 spandex * 70 den) Ends per inch86, Picks per inch 52 and washes process includes Stone wash, Rinse wash, Bleaching and Enzyme wash. Once the samples were ready, they were subjected to tensile and tear strength tests, for these two kinds of samples were considered. One washed fabric samples of warp direction type and other type of the samples was weft direction. Then five samples from each were considered for tensile and teat strength tests separately then takes the mean value. The results found that the lowest strength damaged in the weft direction observed by tensile strength test & Enzyme wash. Maximum breaking load of the enzyme washed fabric sample was 42 kg.

Keywords: twill, indigo dye, tear strength, loom, ball warp, denier or den, seam, waist band, pilling, selvage

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Authors: Asiful H. Seikh, Jabair A. Mohammed, Ubair A. Samad, Mohammad A. Alam, Saeed M. Al-Zahrani, El-Sayed M. Sherif

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Three coating formulations were fabricated by incorporating different percentages of MIO (micaceous iron oxide ) (1, 2, and wt%) with ball-milled nanocrystalline Al (2 wt%) particles, which was optimized earlier. These coatings were characterized by means of different methods, namely, SEM, TGA, pendulum hardness, scratch test, and nano-indentation. The EIS measurements were carried out to report the effect of adding MIO powder in fabricated coatings on their corrosion behavior in 3.5 wt% NaCl solutions. In order to report the effect of immersion time on the corrosion and degradation of the prepared coatings, the EIS data were also acquired after various exposure periods of time, i.e., 1 h, 7 d, 14 d, 21 d, and 30 d in the test chloride solution. It has been found that the obtained EIS data for the fabricated coatings proved that the presence of 2% MIO provided the highest corrosion resistance amongst all coatings and that effect was recorded after all immersion periods of time. But, the MIO-incorporated coatings have less corrosion resistance than Al based epoxy coatings. It was also shown that with prolonged immersion, the resistance to corrosion declined after 7d, then with a longer period of immersion, i.e. 14 d, 21 d, and 30 d increases the resistance to corrosion by forming oxide products on the coatings surface. The results obtained from both mechanical and electrochemical testing confirmed that the fabricated coating with 2 wt% Al exhibited better hardness and higher resistance to corrosion as compared to coatings with 1 wt% Al and 3 wt% Al.

Keywords: epoxy coatings, nanomaterials, corrosion resistance, EIS, nanoindentation

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Authors: Natcha Laethongkham, Gayan Ramanayake, Philip Charlesworth, Leshan Uggalla

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The throttling process in hybrid rocket engines (HREs) poses challenges due to inherent instability, impacting the engine’s reliability and robustness. Identifying and advancing existing technology is crucial to meet the demands of complex mission profiles required for next-generation launch vehicles. This paper reviews the current literature, focusing on oxidiser flow control for throttling purposes in HREs. Covered areas include oxidiser choices, commonly used throttle valves, and literature trends. Common oxidisers for throttling are hydrogen peroxide, nitrous oxide, and liquid oxygen. Two frequently chosen valves for throttling are the ball and variation pintle valves. The review identifies two primary research focuses: flow control valve studies and control system design. The current research stage is highlighted, and suggestions for future directions are proposed to advance thrust control systems in HREs. This includes further studies in existing research focuses and exploring new approaches such as system scheme design, numerical modelling, and applications.

Keywords: hybrid rocket engines, oxidiser flow control, thrust control, throttle valve, review

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Authors: Hemad Zareiforoush, Saeed Minaei, Ahmad Banakar, Mohammad Reza Alizadeh

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The quality inspection of rice (Oryza sativa L.) during its various processing stages is very important. In this research, an artificial intelligence-based model coupled with computer vision techniques was developed as a decision support system for qualitative grading of rice grains. For conducting the experiments, first, 25 samples of rice grains with different levels of percentage of broken kernels (PBK) and degree of milling (DOM) were prepared and their qualitative grade was assessed by experienced experts. Then, the quality parameters of the same samples examined by experts were determined using a machine vision system. A grading model was developed based on fuzzy logic theory in MATLAB software for making a relationship between the qualitative characteristics of the product and its quality. Totally, 25 rules were used for qualitative grading based on AND operator and Mamdani inference system. The fuzzy inference system was consisted of two input linguistic variables namely, DOM and PBK, which were obtained by the machine vision system, and one output variable (quality of the product). The model output was finally defuzzified using Center of Maximum (COM) method. In order to evaluate the developed model, the output of the fuzzy system was compared with experts’ assessments. It was revealed that the developed model can estimate the qualitative grade of the product with an accuracy of 95.74%.

Keywords: machine vision, fuzzy logic, rice, quality

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Authors: Eze Catherine Chinwe, J. D. Njoku

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Background: Palm oil mill effluent is the voluminous liquid waste that comes from the sterilization and clarification sections of the oil palm milling process. The raw effluent contains 90-95% water and includes residual oil, soil particles, and suspended solids. Palm oil mill effluent is a highly polluting material and much research has been dedicated to means of alleviating its threat to the environment. Objectives: 1. To compare Physico-chemical and microbiological analysis of soil samples from POME and non-POME sites. 2. To make recommendations on how best to handle POME in the study area. Methods: Quadrant approach was adopted for sampling POME (A) and Non POME (B) locations. Qualities were determined using standard analytical procedures. Conclusions: Results of the analysis were obtained in the following range; pH (3.940 –7.435), dissolved oxygen (DO) (1.582–6.234mg/l), biological oxygen demand (BOD) (50–5463mg/l etc. For the various locations, the population of total heterotrophic bacteria (THB) ranged from 1.36x106–2.42x106 cfu/ml, the total heterotrophic fungi (THF) ranged from 1.22–3.05 x 104 cfu/ml. The frequency of occurrence revealed the microbial isolates Pseudomonas sp., Bacillus sp., Staphylococcus, as the most frequently occurring isolates. Analysis of variance showed that there were significant differences (P<0.05) in microbial populations among locations. The discharge of industrial effluents into the soil in Nigeria invariably results in the presence of high concentrations of pollutant in the soil environment.

Keywords: effluents, mirobial composition, soil samples, isiala mbano

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Authors: Stanely Nsubuga

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Background In Uganda, injection drug use is a growing but less studied problem. Preventing the transition to injection drug use may help prevent blood-borne viral transmission, but little is known about when and how people transition to injection drug use. A greater understanding of this transition process may aid in the country’s efforts to prevent the continued growth of injection drug use, HIV, and hepatitis C Virus (HCV) infection among people who inject drugs (PWID). Methods Using a rapid situation assessment framework, we conducted semi-structured interviews among 125 PWID (102 males and 23 females)—recruited through outreach and snow-ball sampling. Participants were interviewed about their experiences on when and how they transitioned into injection drug use and these issues were also discussed in 12 focus groups held with the participants. Results All the study participants started their drug use career with non-injecting forms including chewing, smoking, and sniffing before transitioning to injecting. Transitioning was generally described as a peer-driven and socially learnt behavior. The participants’ social networks and accessibility to injectable drugs on the market and among close friends influenced the time lag between first regular drug use and first injecting—which took an average of 4.5 years. By the age of 24, at least 81.6% (95.7% for females and 78.4% for males) had transitioned into injecting. Over 84.8% shared injecting equipment during their first injection, 47.2% started injecting because a close friend was already injecting, 26.4% desired to achieve a greater “high” (26.4%) which could reflect drug-tolerance, and 12% out of curiosity.

Keywords: People who Use Drugs, transition, injection drug use, Uganda

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Authors: Soroush Momeni

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Excellent damping capacity and superelasticity of the bulk NiTi shape memory alloy (SMA) makes it a suitable material of choice for tools in machining process as well as tribological systems. Although thin film of NiTi SMA has a same damping capacity as NiTi bulk alloys, it has a poor mechanical properties and undesirable tribological performance. This study aims at eliminating these application limitations for NiTi SMA thin films. In order to achieve this goal, NiTi thin films were magnetron sputtered as an interlayer between reactively sputtered hard TiCN coatings and hard work tool steel substrates. The microstructure, composition, crystallographic phases, mechanical and tribological properties of the deposited thin films were analyzed by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), nanoindentation, ball–on-disc, scratch test, and three dimensional (3D) optical microscopy. It was found that under a specific coating architecture, the superelasticity of NiTi inter-layer can be combined with high hardness and wear resistance of TiCN protective layers. The obtained results revealed that the thickness of NiTi interlayers is an important factor controlling mechanical and tribological performance of bi-layer composite coating systems.

Keywords: PVD coatings, sliding wear, hardness, tool steel

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Authors: John Battersby, Rhys Ball

Abstract:

After the 15 March 2019 Mosque attacks in Christchurch, the New Zealand security sector has had to address its training and preparedness levels for dealing with contemporary terrorist threats as well as potential future manifestations of terrorism. From time to time, members of the academic community from Australia and New Zealand have been asked to assist agencies in this endeavour. In the course of 2018, New Zealand security sector professionals working in the counter-terrorism area were interviewed about how they regarded academic contributions to understanding terrorism and counter-terrorism. Responses were mixed, ranging from anti-intellectualism, a belief that the inability to access classified material rendered academic work practically useless - to some genuine interest and desire for broad based academic studies on issues practitioners did not have the time to look at. Twelve months later, researchers have revisited those spoken to prior to the Brenton Tarrant 15 March shooting to establish if there has been a change in the way academic research is perceived, viewed and valued, and what key factors have contributed to this shift in thinking. This paper takes this data, combined with a consideration of the literature on higher education within professional police and intelligence forces, and on the general perception of academics by practitioners, to present a series of findings that will contribute to a more proactive and effective set of engagements, between two distinct but important security sectors, that reflect more closely with international practice.

Keywords: academic, counter terrorism, intelligence, practitioner, research, security

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Authors: Arth Bohra, Marwa Mahmoud

Abstract:

In this paper, we utilize computer vision to develop a tool for youth coaches to formulate set-piece tactics for their players. We used the Soccernet database to extract the ResNet features and camera calibration data for over 3000 corner kick across 500 professional matches in the top 6 European leagues (English Premier League, UEFA Champions League, Ligue 1, La Liga, Serie A, Bundesliga). Leveraging the provided homography matrix, we construct a feature vector representing the formation of players on these corner kicks. Additionally, labeling the videos manually, we obtained the pass-trajectory of each of the 3000+ corner kicks by segmenting the field into four zones. Next, after determining the localization of the players and ball, we used event data to give the corner kicks a rating on a 1-4 scale. By employing a Convolutional Neural Network, our model managed to predict the success of a corner kick given the formations of players. This suggests that with the right formations, teams can optimize the way they approach corner kicks. By understanding this, we can help coaches formulate set-piece tactics for their own teams in order to maximize the success of their play. The proposed model can be easily extended; our method could be applied to even more game situations, from free kicks to counterattacks. This research project also gives insight into the myriad of possibilities that artificial intelligence possesses in transforming the domain of sports.

Keywords: soccer, corner kicks, AI, computer vision

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Authors: Dicky Eka Putra, S. P. Nadia Chairunissa, Lidia Paramita, Roza Hartati, Ice Yolanda Puri

Abstract:

Background: Soy bean and the products such as tofu, tempeh and soy milk are famous in the community. Moreover, another product is tofu flour which is not familiar in Indonesia yet and it is well known as Okara. There are massive differences of energy, protein and carbohydrate between them which is know as good for protein sources as well. Unfortunately, it is seldom used as food variety. Basically, it can be benefit in order to create many products for example cakes, snacks and some desserts. Aim: the study was in order to promote the benefit of tofu flour as school feeding of elementary school and baby porridge and also to compare the nutrient. Method: Soy pulp was filtered and steamed approximately 30 minutes. Then, it was put at a plate under sunrise or barked on the oven for 10 hours at 800C. When it have dried and milling and tofu flour is ready to be used. Result: Tofu flour could be used as substitute of flour and rice flour when people want to cook some foods. In addition, some references said that soy bean is good for a specific remedy for the proper functioning of the heart, liver, kidneys, stomach, and bowels, constipation, as a stimulant for the lungs, for eradication of poison from the system, improving the complexion by cleaning the skin of impurities, and stimulating the growth and appearance of the hair. Discussion: Comparing between soy bean, tofu and tofu flour which has difference amount of nutrients. For example energy 382 kcal, 79 kcal and 393 kcal respectively and also protein 30.2 kcal, 7.8 kcal, and 17.4 kcal. In addition, carbohydrate of soy pulp was high than soy bean and tofu (30.1 kcal). Finally, local should replace flour, rice and gelatin rice flour with tofu flour.

Keywords: tofu flour, protein, soy bean, school feeding

Procedia PDF Downloads 378

Authors: Saliha Gachi, Mouloud Aissani, Fouad Boubenider

Abstract:

Friction Stir Welding (FSW) is a solid-state welding technique that can join material without melting the plates to be welded. In this work, we are interested to demonstrate the potentiality of FSW for joining the heat-treatable aluminum alloy 2024-T3 which is reputed as difficult to be welded by fusion techniques. Thereafter, the FSW joint is compared with another one obtained from a conventional fusion process Tungsten Inert Gas (TIG). FSW welds are made up using an FSW tool mounted on a milling machine. Single pass welding was applied to fabricated TIG joint. The comparison between the two processes has been made on the temperature evolution, mechanical and microstructure behavior. The microstructural examination revealed that FSW weld is composed of four zones: Base metal (BM), Heat affected zone (HAZ), Thermo-mechanical affected zone (THAZ) and the nugget zone (NZ). The NZ exhibits a recrystallized equiaxed refined grains that induce better mechanical properties and good ductility compared to TIG joint where the grains have a larger size in the welded region compared with the BM due to the elevated heat input. The microhardness results show that, in FSW weld, the THAZ contains the lowest microhardness values and increase in the NZ; however, in TIG process, the lowest values are localized on the NZ.

Keywords: friction stir welding, tungsten inert gaz, aluminum, microstructure

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Authors: Barry Hojjatie

Abstract:

Uniaxial (e.g., three-point bending) and biaxial flexure tests are used frequently for determining the strength of ceramics. It is generally believed that the biaxial test has an advantage as compared to uniaxial test because it produces a state of pure tension on the lower surface of the specimen and the maximum tensile stress, which is usually responsible for crack initiation and failure is unaffected by the edge condition. However, inconsistent strength values have been reported for the same material and testing conditions. The objective of this study was to analyze the strength of dental porcelain materials using the two different test methods and evaluate the main contributions to variability in biaxial testing and to analyze the relative influence of variables such as specimen geometric conditions and loading conditions on calculated strength of porcelain subjected to biaxial testing. Porcelain disks (16 mm dia x 2 mm thick) were subjected to biaxial flexure (pin-on-three-ball), and flexure strength values were calculated. A 3-D finite element model was developed to simulate various biaxial flexure test conditions. Stresses were analyzed for ceramic thickness in the range of 1.0-3.0 mm. For a 2-mm-thick disk subjected to a point load of 200 N, the maximum tensile stress at the lower surface was 180 MPa. This stress decreased to 95, 77, 68, and 59 MPa for the radius of the load values of 0.15, 0.3, 0.6, and 1.0 mm, respectively. Tensile stresses which developed at the top surface near the site of loading were small for the radius of the load ≥ 0.6 mm.

Keywords: ceramis, biaxial, flexure test, uniaxial

Procedia PDF Downloads 155