Search results for: physical vapor deposition coating method

Authors: Muhammad Wahb

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Physical activity is increasingly recognized as a significant factor in maintaining optimal health and preventing chronic diseases. This research scrutinizes the long-term health benefits of sustained physical activity, employing a systematic review of epidemiological studies and randomized control trials conducted over the past decade. The study illuminates the protective effects of regular physical activity against cardiovascular disease, obesity, diabetes, and mental health disorders, with a special focus on the mechanisms involved. Furthermore, the paper provides insights into how public health initiatives can effectively promote physical activity among diverse populations, contributing to improved community health outcomes.

Keywords: physical activity, long-term health benefits, chronic disease prevention, public health

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Authors: H. Gholami, M. Jalali Azizpour

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Stress Corrosion Crack (SCC) in pipeline is a type of environmentally assisted cracking (EAC), since its discovery in 1965 as a possible cause of failure in pipeline, SCC has caused, on average, one of two failures per year in the U.S, According to the NACE SCC DA a pipe line segment is considered susceptible to SCC if all of the following factors are met: The operating stress exceeds 60% of specified minimum yield strength (SMYS), the operating temperature exceeds 38°C, the segment is less than 32 km downstream from a compressor station, the age of the pipeline is greater than 10 years and the coating type is other than Fusion Bonded Epoxy(FBE). In this paper as a practical experience in NISOC, Direct Assessment (DA) Method is used for identification SCC defect in unpiggable pipeline located downstream of compressor station.

Keywords: stress corrosion crack, direct assessment, disbondment, transgranular SCC, compressor station

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Authors: Salwa M. Elmesallamy, Ahmed A. Farag, Magd M. Badr, Dalia S. Fathy, Ahmed Bakry, Mona A. El-Etre

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The term green environment is an international trend. It is become imperative to treat the corrosion of steel with a green coating to protect the environment. From the potential adverse effects of the traditional materials.A series of polybenzoxazine/henna composites (PBZ/henna), with different weight percent (3,5, and 7 wt % (of henna), were prepared for corrosion protection of carbon steel. The structures of the prepared composites were verified using FTIR analysis. The mechanical properties of the resins, such as adhesion, hardness, binding, and tensile strength, were also measured. It was found that the tensile strength increases by henna loading up to 25% higher than the tidy resin. The thermal stability was investigated by thermogravimetric analysis (TGA) the loading of lawsone (henna) molecules into the PBZ matrix increases the thermal stability of the composite. UV stability was tested by the UV weathering accelerator to examine the possibility that henna can also act as an aging UV stabilizer. The effect of henna content on the corrosion resistance of composite coatings was tested using potentiostatic polarization and electrochemical spectroscopy. The presence of henna in the coating matrix enhances the protection efficiency of polybenzoxazine coats. Increasing henna concentration increases the protection efficiency of composites. The quantum chemical calculations for polybenzoxazine/henna composites have resulted that the highest corrosion inhibition efficiency, has the highest EHOMO and lowest ELUMO; which is in good agreement with results obtained from experiments.

Keywords: polybenzoxazine, corrosion, green chemistry, carbon steel

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Authors: Hamadi Cherif, Christophe Coquelet, Paolo Stringari, Denis Clodic, Laura Pellegrini, Stefania Moioli, Stefano Langè

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Biogas is a promising technology which can be used as a vehicle fuel, for heat and electricity production, or injected in the national gas grid. It is storable, transportable, not intermittent and substitutable for fossil fuels. This gas produced from the wastewater treatment by degradation of organic matter under anaerobic conditions is mainly composed of methane and carbon dioxide. To be used as a renewable fuel, biogas, whose energy comes only from methane, must be purified from carbon dioxide and other impurities such as water vapor, siloxanes and hydrogen sulfide. Purification of biogas for this application particularly requires the removal of hydrogen sulfide, which negatively affects the operation and viability of equipment especially pumps, heat exchangers and pipes, causing their corrosion. Several methods are available to eliminate hydrogen sulfide from biogas. Herein, reactive absorption in structured packed column by means of chemical absorption in aqueous sodium hydroxide solutions is considered. This study is based on simulations using Aspen Plus™ V8.0, and comparisons are done with data from an industrial pilot plant treating 85 Nm3/h of biogas which contains about 30 ppm of hydrogen sulfide. The rate-based model approach has been used for simulations in order to determine the efficiencies of separation for different operating conditions. To describe vapor-liquid equilibrium, a γ/ϕ approach has been considered: the Electrolyte NRTL model has been adopted to represent non-idealities in the liquid phase, while the Redlich-Kwong equation of state has been used for the vapor phase. In order to validate the thermodynamic model, Henry’s law constants of each compound in water have been verified against experimental data. Default values available in Aspen Plus™ V8.0 for the properties of pure components properties as heat capacity, density, viscosity and surface tension have also been verified. The obtained results for physical and chemical properties are in a good agreement with experimental data. Reactions involved in the process have been studied rigorously. Equilibrium constants for equilibrium reactions and the reaction rate constant for the kinetically controlled reaction between carbon dioxide and the hydroxide ion have been checked. Results of simulations of the pilot plant purification section show the influence of low temperatures, concentration of sodium hydroxide and hydrodynamic parameters on the selective absorption of hydrogen sulfide. These results show an acceptable degree of accuracy when compared with the experimental data obtained from the pilot plant. Results show also the great efficiency of sodium hydroxide for the removal of hydrogen sulfide. The content of this compound in the gas leaving the column is under 1 ppm.

Keywords: biogas, hydrogen sulfide, reactive absorption, sodium hydroxide, structured packed column

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Authors: A. Rinaldi, A. Proietti, C. Aquarelli, F. Marra, A. Tamburrano, M. Ciminello, M. S. Sarto

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A new type of high sensitive piezoresistive sensors based on graphene was developed within the SARISTU project for application on Structural Health Monitoring (SHM). The new sensor consists of a graphene-based film, obtained through the spray deposition of a colloidal suspension of Multi-Layer Graphene (MLGs) nano platelets over a substrate. MLGs are produced by liquid exfoliation of thermally expanded Graphite Intercalation Compound. An array of 8 sensors is produced by spray deposition over an aeronautical CFRC plate of dimensions 550 mm (length) × 550 mm (width) × 3 mm (thickness). Electromechanical tests were performed in order to assess the sensitivity of the new piezoresistive sensors, which are characterized by an isotropic response. In the quasi-static characterizations, the CFRC plate was clamped on one side and loaded on the opposite one. The local strain map of the plate was then obtained from displacement measurements and numerical analysis. The dynamic tests were performed lying the plate over an anti-vibration table and actuating a piezoelectric element located in the middle of the sensing array. The obtained experimental results demonstrated that the sensors possess a good repeatability and a high constant gauge factor (~200) in the applied strain range 0.001%-0.02%. Moreover, they can follow dynamics up to 400 kHz and for this reason they are good candidates for Lamb-wave analysis.

Keywords: graphene, strain sensor, spray deposition, lamb-wave analysis

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Authors: Ubeyd Toçoğlu, Miraç Alaf, Hatem Akbulut

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We present a work which was conducted in order to improve the cycle life of silicon based lithium ion battery anodes by utilizing novel composite structure. In this study, carbon coated nano sized (50-100 nm) silicon particles were embedded into Graphene/MWCNT silicon matrix to produce free standing silicon based electrodes. Also, conventional Si powder anodes were produced from Si powder slurry on copper current collectors in order to make comparison of composite and conventional anode structures. Free –standing composite anodes (binder-free) were produced via vacuum filtration from a well dispersion of Graphene, MWCNT and carbon coated silicon powders. Carbon coating process of silicon powders was carried out via microwave reaction system. The certain amount of silicon powder and glucose was mixed under ultrasonication and then coating was conducted at 200 °C for two hours in Teflon lined autoclave reaction chamber. Graphene which was used in this study was synthesized from well-known Hummers method and hydrazine reduction of graphene oxide. X-Ray diffraction analysis and RAMAN spectroscopy techniques were used for phase characterization of anodes. Scanning electron microscopy analyses were conducted for morphological characterization. The electrochemical performance tests were carried out by means of galvanostatic charge/discharge, cyclic voltammetry and electrochemical impedance spectroscopy.

Keywords: graphene, Li-Ion, MWCNT, silicon

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Authors: A. Nguyen, K. Nguyen, J. Jackson, E. Manlapig

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With the recent advancement in core imaging systems, a large volume of high resolution drill core images can now be collected rapidly. This paper presents a method for rapid prediction of ore-specific breakage parameters from high resolution mineral classified core images. The aim is to allow for a rapid assessment of the variability in ore hardness within a mineral deposit with reduced amount of physical breakage tests. This method sees its application primarily in project evaluation phase, where proper evaluation of the variability in ore hardness of the orebody normally requires prolong and costly metallurgical test work program. Applying this image-based texture analysis method on mineral classified core images, the ores are classified according to their textural characteristics. A small number of physical tests are performed to produce a dataset used for developing the relationship between texture classes and measured ore hardness. The paper also presents a case study in which this method has been applied on core samples from a copper porphyry deposit to predict the ore-specific breakage A*b parameter, obtained from JKRBT tests.

Keywords: geometallurgy, hyperspectral drill core imaging, process simulation, texture analysis

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Authors: Andrew Terhemen Tyowua, Zhibing Zhang, Michael J. Adams

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Water vapor sorption data at a range of temperatures (25–70 °C) have been obtained for starch (corn and wheat) and non-starch (carrageenan and xanthan gum) hydrocolloid particles in the form of a thin slab. The results reveal that the data may be more accurately described by an existing sigmoidal rather than a Fickian model. The sigmoidal model accounts for the initial surface sorption before the onset of bulk diffusion. At relatively small water activities (≤ 0.3), the absorption of the moisture caused the particles to be plasticized, but at greater activity values (> 0.3), anti-plasticization was induced. However, it was found that for the whole range of water activities and temperatures studied, the data could be characterized by a single non-dimensional number, which was termed the non-Fickian diffusion number where τ is the characteristic time of surface sorption, D is the bulk diffusion coefficient and L is the thickness of the layer of particles. The activation energy suggested that the anti-plasticization mechanism was the result of a reduction in the molecular free volume or an increase in crystallinity.

Keywords: anti-plasticization, arrhenius behavior, diffusion coefficient, hygroscopic polymers, moisture migration, non-fickian sigmoidal model

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Authors: C. Paglia, C. Mosca

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Synthetic resin floorsare often used in sport infrastructure. These organic materials are often in contact with a bituminous substrate, which in turn is placed on the ground. In this work, the damage of a basket resin field surface was characterized by means of visual inspection, optical microscopy, resin thickness measurements, adhesion strength, water vapor transmission capacity, capillary water adsorption, granulometry of the bituminous conglomerate, the surface properties, and the water ground infiltration speed. The infiltration speed indicates water pemeability. This was due to its composition: clean sand mixed with gravel. Relatively good adhesion was present between the synthetic resin and the bituminous layer. The adhesion resistance of the bituminous layer was relatively low. According to the required bitumoniousasphalt-concrete mixes AC 11 S, the placed material was more porous. Insufficient constipation was present. The spaces values were above the standard limits, while the apparent densities were lower compared to the conventional AC 11 mixtures. The microstructure outlines the high permeability and porosity of the bituminous layer. The synthetic resin wasvapourproof and did not exhibit capillary adsorption. It exhibited a lower thickness as required, and no multiple placing steps were observed. Multiple cavities were detected along with the interface between the bituminous layer and the resin coating with no intermediate layers. The layer for the pore filling in the bituminous surface was not properly applied. The swelling bubbles on the synthetic pavement were caused by the humidity in the bituminous layer. Water or humidity were present prior to the application of the resin, and the effect was worsened by the upward movement of the water from the ground.

Keywords: resin, floor, damage, durability

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Authors: Kazem Sabet-Bokati, Ilia Rodionov, Marciel Gaier, Kevin Plucknett

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Protective coatings play a pivotal role in mitigating corrosion and preserving the integrity of metallic structures exposed to harsh environmental conditions. The diversity of corrosive environments necessitates the development of protective coatings suitable for various conditions. Accurately selecting and interpreting analysis methods is crucial in identifying the most suitable protective coatings for the various corrosive environments. This study conducted a comprehensive comparative analysis of traditional and advanced methods to assess the anti-corrosion performance of sacrificial and barrier coatings. The protective performance of pure epoxy, zinc-rich epoxy, and cold galvanizing coatings was evaluated using salt spray tests, together with electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. The performance of each coating was thoroughly differentiated under both atmospheric and immersion conditions. The distinct protective performance of each coating against atmospheric corrosion was assessed using traditional standard methods. Additionally, the electrochemical responses of these coatings in immersion conditions were systematically studied, and a detailed discussion on interpreting the electrochemical responses is provided. Zinc-rich epoxy and cold galvanizing coatings offer superior anti-corrosion performance against atmospheric corrosion, while the pure epoxy coating excels in immersion conditions.

Keywords: corrosion, barrier coatings, sacrificial coatings, salt-spray, EIS, polarization

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Authors: Seyedebrahim Afkhami, Meisam Abdi, Reza Baserinia

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Additive manufacturing is revolutionising production in different industries, including pharmaceuticals. This case study explores the influence of surface area on the dissolution of additively manufactured polyvinyl alcohol parts as a polymer candidate. Specimens of different geometries and constant mass were fabricated using a Fused Deposition Modelling 3D printer. The dissolution behaviour of these samples was compared with respect to their surface area. Improved and accelerated dissolution was observed for samples with a larger surface area. This study highlights the capabilities of additive manufacturing to produce samples of complex geometries that cannot be manufactured otherwise to control the dissolution behaviour for pharmaceutical and biopharmaceutical applications.

Keywords: additive manufacturing, polymer dissolution, fused deposition modelling, geometry optimization

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Authors: M. Chiliza, H. P. Mbukwane, P Masita, H. Rutto

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Acid mine drainage (AMD) one of the main pollutants of water in many countries that have mining activities. AMD results from the oxidation of pyrite and other metal sulfides. When these metals gets exposed to moisture and oxygen, leaching takes place releasing sulphate and Iron. Acid drainage is often noted by 'yellow boy,' an orange-yellow substance that occurs when the pH of acidic mine-influenced water raises above pH 3, so that the previously dissolved iron precipitates out. The possibility of using environmentally friendly silane and phosphate based coatings on pyrite to remediate acid mine drainage and prevention at source was investigated. The results showed that both coatings reduced chemical oxidation of pyrite based on Fe and sulphate release. Furthermore, it was found that silane based coating performs better when coating synthesis take place in a basic hydrolysis than in an acidic state.

Keywords: acid mine drainage, pyrite, silane, phosphate

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Authors: Swapnil A. Padvi, Dipak S. Dalal

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The chemistry of tetrazoles has been grown tremendously in the past few years because tetrazoles are important and useful class of heterocyclic compounds which have a widespread application such as anticancer, antimicrobial, analgesics, antibacterial, antifungal, antihypertensive, and anti-allergic drugs in medicinal chemistry. Furthermore, tetrazoles have application in material sciences as explosives, rocket propellants, and in information recording systems. In addition to this, they have a wide range of application in coordination chemistry as a ligand. Deep eutectic solvents (DES) have emerged over the current decade as a novel class of green reaction media and applied in various fields of sciences because of their unique physical and chemical properties similar to the ionic liquids such as low vapor pressure, non-volatility, high thermal stability and recyclability. In addition, the reactants of DES are cheaply available, low-toxic, and biodegradable, which makes them predominantly required for large-scale applications effectively in industrial production. Herein we report the [2+3] cycloaddition reaction of organic nitriles with sodium azide affords the corresponding 5-substituted 1H-tetrazoles in six different types of choline chloride based deep eutectic solvents under mild reaction condition. Choline chloride: ZnCl2 (1:2) showed the best results for the synthesis of 5-substituted 1 H-tetrazoles. This method reduces the disadvantages such as: the use of toxic metals and expensive reagents, drastic reaction conditions and the presence of dangerous hydrazoic acid. The approach provides environment-friendly, short reaction times, good to excellent yields; safe process and simple workup make this method an attractive and useful contribution to present green organic synthesis of 5-substituted-1H-tetrazoles. All synthesized compounds were characterized by IR, 1H NMR, 13C NMR and Mass spectroscopy. DES can be recovered and reused three times with very little loss in activity.

Keywords: click chemistry, choline chloride, green chemistry, deep eutectic solvent, tetrazoles

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Authors: S. Chikh, S. Boulifa

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The present study addresses the problem of ammonia evaporation during filling of a vertical cylindrical tank and the influence of various external factors on the stability of storage by determining the conditions for minimum evaporation. Numerical simulation is carried out by solving the governing equations namely, continuity, momentum, energy, and diffusion of species. The effect of temperature of surrounding air, the filling speed of the reservoir and the temperature of the filling liquid ammonia on the evaporation rate is investigated. Results show that the temperature of the filling liquid has little effect on the liquid ammonia for a short period, which, in fact, is function of the filling speed. The evaporation rate along the free surface of the liquid is non-uniform. The inlet temperature affects the vapor ammonia temperature because of pressure increase. The temperature of the surrounding air affects the temperature of the vapor phase rather than the liquid phase. The maximum of evaporation is reached at the final step of filling. In order to minimize loss of ammonia vapors automatically causing losses in quantity of the liquid stored, it is suggested to ensure the proper insulation for the walls and roof of the reservoir and to increase the filling speed.

Keywords: evaporation, liquid ammonia, storage tank, numerical simulation

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Authors: Manjinder Bajwa, Mahipal Singh, Ashish Tulli

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In the research, the effect of varying cutting parameters, design parameters and heat treatment processes were studied on the cutting performance (Tool life) of a PVD coated tool. Thus, in a quest for these phenomenon comparison, a single coated tool and a multicoated tool were analyzed after suitable heat treatment process. TNMG shaped insert with single coating of TiCN and multi-coating of TiAlN/TiN were developed on tungsten carbide substrate. These coated inserts were then successfully annealed and normalized for a temperature of 350°C for 30 minutes and their cutting performance was evaluated as per the flank wear obtained after turning of mild steel. The results showed that heat treatment had a suitable impact on the tool life of the coated insert and also led to increase in the micro-hardness of the tool coatings and decrease in the wear rate.

Keywords: PVD coatings, flank wear, micro-hardness, annealing, normalizing

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Authors: Zuzana Sedláková, Magda Kárászová, Jiří Vejražka, Lenka Morávková, Pavel Izák

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Membrane separations are mentioned frequently as a possibility for CO2 capture. Selectivity of ionic liquid membranes is strongly determined by different solubility of separated gases in ionic liquids. The solubility of separated gases usually varies over an order of magnitude, differently from diffusivity of gases in ionic liquids, which is usually of the same order of magnitude for different gases. The present work evaluates the selection of an appropriate ionic liquid for the selective membrane preparation based on the gas solubility in an ionic liquid. The current state of the art of CO2 capture patents and technologies based on the membrane separations was considered. An overview is given of the discussed transport mechanisms. Ionic liquids seem to be promising candidates thanks to their tunable properties, wide liquid range, reasonable thermal stability, and negligible vapor pressure. However, the uses of supported liquid membranes are limited by their relatively short lifetime from the industrial point of view. On the other hand, ionic liquids could overcome these problems due to their negligible vapor pressure and their tunable properties by adequate selection of the cation and anion.

Keywords: biogas upgrading, carbon dioxide separation, ionic liquid membrane, transport properties

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Authors: Isam A. H. Al Zubaidy

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A quick process may be needed to get the benefit the big generated quantity of waste oil sludge (WOS). The process includes the mixing process of WOS with commercial diesel fuel. Different ratios of WOS to diesel fuel were prepared ranging 1:1 to 20:1 by mass. The mixture was continuously mixing for 10 minutes using bench type overhead stirrer and followed by filtration process to separate the soil waste from filtrate oil product. The quantity and the physical properties of the oil filtrate were measured. It was found that the addition of up to 15% WOS to diesel fuel was accepted without dramatic changes to the properties of diesel fuel. The amount of waste oil sludge was decreased by about 60% by mass. This means that about 60 % of the mass of sludge was recovered as light fuel oil. The physical properties of the resulting fuel from 10% sludge mixing ratio showed that the specific gravity, ash content, carbon residue, asphaltene content, viscosity, diesel index, cetane number, and calorific value were affected slightly. The color was changed to light black color. The sulfur content was increased also. This requires other processes to reduce the sulfur content of the resulting light fuel. A new desulfurization process was achieved using adsorption techniques with activated biomaterial to reduce the sulfur content to acceptable limits. Adsorption process by ZnCl₂ activated date palm kernel powder was effective for improvement of the physical properties of diesel like fuel. The final sulfur content was increased to 0.185 wt%. This diesel like fuel can be used in all tractors, buses, tracks inside and outside the refineries. The solid remaining seems to be smooth and can be mixed with asphalt mixture for asphalting the roads or can be used with other materials as an asphalt coating material for constructed buildings. Through this process, valuable fuel has been recovered, and the amount of waste material had decreased.

Keywords: oil sludge, diesel fuel, blending process, filtration process

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Authors: Muhammad Rafiullah Khan, Vanee Chonhenchob

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The effect of sodium alginate (1%) based edible coating incorporated natural essential oils; thymol, carvone and carvacrol as antimicrobial agents at different concentrations (0.1, 0.5 and 1.0 %) on the quality changes of fresh-cut pineapple were investigated. Pineapple dipped in distilled water was served as control. After coating, fruit were sealed in a modified atmosphere package (MAP) using high permeable film; and stored at 5 °C. Gas composition in package headspace, color values (L*, a*, b*, C*), TSS, pH, ethanol, browning, and microbial decay were monitored during storage. Oxygen concentration continuously decreased while carbon dioxide concentration inside all packages continuously increased over time. Color parameters (L*, b*, c*) decreased and a* values increased during storage. All essential oils significantly (p ≤ 0.05) prevented microbial growth than control. A significantly higher (p ≤ 0.05) ethanol content was found in the control than in all other treatments. Visible microbial growth, high ethanol, and low color values limited the shelf life to 6 days in control as compared to 9 days in all other treatments. Among all essential oils, thymol at all concentrations maintained the overall quality of the pineapple and could potentially be used commercially in fresh fruit industries for longer storage.

Keywords: essential oils, antibrowning agents, antimicrobial agents, modified atmosphere packaging, pineapple, microbial decay

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Authors: Muhammad Rafiullah Khan, Vanee Chonhenchob

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The effect of sodium alginate (1%) based edible coating incorporated natural essential oils, thymol, carvone, and carvacrol as antimicrobial agents at different concentrations (0.1, 0.5, and 1.0%) on the quality changes of fresh-cut pineapple was investigated. Pineapple dipped in distilled water was served as control. After coating, the fruit was sealed in a modified atmosphere package (MAP) using high permeable film and stored at 5°C. Gas composition in package headspace, color values (L*, a*, b*, C*), TSS, pH, ethanol, browning, and microbial decay were monitored during storage. Oxygen concentration continuously decreased while carbon dioxide concentration inside all packages continuously increased over time. Color parameters (L*, b*, c*) decreased, and a* values increased during storage. All essential oils significantly (p ≤ 0.05) prevented microbial growth than control. A significantly higher (p ≤ 0.05) ethanol content was found in the control than in all other treatments. Visible microbial growth, high ethanol, and low color values limited the shelf life to 6 days in control as compared to 9 days in all other treatments. Among all essential oils, thymol at all concentrations maintained the overall quality of the pineapple and could potentially be used commercially in fresh fruit industries for longer storage.

Keywords: essential oils, antibrowning agents, antimicrobial agents, modified atmosphere packaging, microbial decay, pineapple

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Authors: K. M. Kheiralla, M. A. Ali, M. Y. Abdelgalil, N. E. Mohamed, G. Boutsis

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The present study focus on integrated geophysical surveys carried out in the mineralization zone in Erkowit region, Eastern Sudan to determine the extensions of the potential ore deposits on the topographically high hilly area and under the cover of alluvium along the nearby wadi and to locate other occurrences if any. The magnetic method (MAG) and the electrical resistivity tomography (ERT) were employed for the survey. Eleven traverses were aligned approximately at right angles to the general strike of the rock formations. The disseminated sulfides are located on the alteration shear zone which is composed of granitic and dioritic highly ferruginated rock occupying the southwestern and central parts of the area, this was confirmed using thin and polished sections mineralogical analysis. The magnetic data indicates low magnetic values for wadi sedimentary deposits in its southern part of the area, and high anomalies which are suspected as gossans due to magnetite formed during wall rock alteration consequent to mineralization. The significant ERT images define low resistivity zone as traced as sheared zones which may associated with the main loci of ore deposition. The study designates that correlation of magnetic and ERT anomalies with lithology are extremely useful in mineral exploration due to variations in some specific physical properties of rocks.

Keywords: ERT, magnetic, mineralization, Red Sea, Sudan

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Authors: Annika Skansberg

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Electronic cigarettes (e-cigarettes) use vapor to deliver nicotine, have recently become popular, especially amongst adolescents. Because of this, the FDA has decided to regulate e-cigarettes, and therefore would like to determine the abuse liability of the products compared to traditional nicotine products. This will allow them to determine the impact of regulating them on public health and shape the decisions they make when creating new laws. This study assessed the abuse liability of Aroma E-juice Dark Honey Tobacco compared to nicotine using an animal model. This e-liquid contains minor alkaloids that may increase abuse liability compared to nicotine alone. The abuse liability of nicotine alone and e-juice liquid were compared in rats using intracranial self-stimulation (ICSS) thresholds. E-liquid had less aversive effects at high nicotine doses in the ICSS model, suggesting that the minor alkaloids in the e-liquid allow users to use higher doses without experiencing the negative effects felt when using high doses of nicotine alone. This finding could mean that e-cigarettes have a higher abuse liability than nicotine alone, but more research is needed before this can be concluded. These findings are useful in observing the abuse liability of e-cigarettes and will help inform the FDA while regulating these products.

Keywords: electronic cigarettes, intra-cranial self stimulation, abuse liability, anhedonia

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Authors: Mahta Eskandarnejad

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The aim of this paper was to compare physical activity and mental toughness in the staff and students of the University of Tabriz. 615 people participated in this study and filled demographic questionnaire, mental thoughness48 (MTQ48) questionnaire and habitual physical activity questionnaire (Baecke physical activity questionnaire). The research sample included 355 students and 260 staff (615 questionnaires). For analyzing hypotheses MANOVA, correlation and independent t-test were used. Based on the result; some subscales of mental toughness and physical activity were significantly related. The result showed the significant correlation between mental toughness and physical activity in student and no significant correlation in staff. Students were significantly physically more active than staff, and mental toughness was higher in staff. There was no difference in mental toughness variable between active participants (active staff and student). The results of this study showed that mental toughness could influence the way a person cope with living conditions. It is expected that mental toughness changes can lead to changing in levels of physical activity. It should be noted that the other variables should not be ignored.

Keywords: Baecke physical activity questionnaire, mental toughness, physical activity, university staff, university student

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Authors: Xue Ma, Yang Fu, Dangyuan Lei

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Passive daytime radiative cooling is an emerging technology which has attracted worldwide attention in recent years due to its huge potential in cooling buildings without the use of electricity. Various coating materials with different optical properties have been developed to improve the daytime radiative cooling performance. However, commercial cooling coatings comprising functional fillers with optical bandgaps within the solar spectral range suffers from severe intrinsic absorption, limiting their cooling performance. Fortunately, it has recently been demonstrated that introducing fluorescent materials into polymeric coatings can covert the absorbed sunlight to fluorescent emissions and hence increase the effective solar reflectance and cooling performance. In this paper, we experimentally investigate the key factors for fluorescence-assisted radiative cooling with TiO2-based white coatings. The surrounding TiO2 nanoparticles, which enable spatial and temporal light confinement through multiple Mie scattering, lead to Purcell enhancement of phosphors in the coating. Photoluminescence lifetimes of two phosphors (BaMgAl10O17:Eu2+ and (Sr, Ba)SiO4:Eu2+) exhibit significant reduction of ~61% and ~23%, indicating Purcell factors of 2.6 and 1.3, respectively. Moreover, smaller Stokes shifts of the phosphors are preferred to further diminish solar absorption. Field test of fluorescent cooling coatings demonstrate an improvement of ~4% solar reflectance for the BaMgAl10O17:Eu2+-based fluorescent cooling coating. However, to maximize solar reflectance, a white appearance is introduced based on multiple Mie scattering by the broad size distribution of fillers, which is visually pressurized and aesthetically bored. Besides, most colored pigments absorb visible light significantly and convert it to non-radiative thermal energy, offsetting the cooling effect. Therefore, current colored cooling coatings are facing the compromise between color saturation and cooling effect. To solve this problem, we introduced colored fluorescent materials into white coating based on SiO2 microspheres as a top layer, covering a white cooling coating based on TiO2. Compared with the colored pigments, fluorescent materials could re-emit the absorbed light, reducing the solar absorption introduced by coloration. Our work investigated the scattering properties of SiO2 dielectric spheres with different diameters and detailly discussed their impact on the PL properties of phosphors, paving the way for colored fluorescent-assisted cooling coting to application and industrialization.

Keywords: solar reflection, infrared emissivity, mie scattering, photoluminescent emission, radiative cooling

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Authors: Isaac Yeboah

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Physical activity (PA) is considered the best preventative tool for maintaining physical health and extending lifespan because it offers a range of benefits. However, for people to benefit from physical activity, it must be done at a level that can enhance fitness, health, and overall well-being. Therefore, this study aimed to determine the link between physical activity participation levels and cardiorespiratory fitness (CRF). The study employed the descriptive correlational design. The census sampling technique included all 190 teaching staff from the two senior high schools in the Dormaa East District. An adapted International Physical Activity Questionnaire (IPAQ) and standardized physical fitness tests were used for data collection. Descriptive statistics of frequency counts and percentages were used to answer the research questions, while inferential statistics of Pearson Product Moment Correlation and the independent sample t-test were used to test hypotheses one and two, respectively. A moderately negative (r = -.156) relationship existed between physical activity participation levels and CRF. Female teachers demonstrated a statistically significant value (p = .045) than males. The study concluded that the reported physical activity levels of the teachers did not reflect their CRF. The implication is that either the participants overestimated their physical activity participation levels or the intensity of the activities was not high enough to affect physiological changes. For the teachers' CRF to improve, it was suggested, among other things, that regular physical activity sessions of the appropriate mixes of FITT be organized.

Keywords: physical activity, participation levels, cardiorespiratory fitness, sedentary lifestyle, teachers

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Authors: Laurenn Borges de Macedo, Fabiane Salles Ferro, Tiago Hendrigo de Almeida, Gérson Moreira de Lima, André Luiz Christoforo, Francisco Antonio Rocco Lahr

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The growth of the furniture manufacturing industry is one of the fundamental factors contributing to the growth of the particleboard industry. The use of recycled products into particleboards can contribute to the forest conservation, in addition to achieve a high quality sustainable product with low-cost production. This work investigates the effect of bi-oriented polypropylene (BOPP) waste particles and sealing product on the physical and mechanical properties of Eucalyptus sp. particleboards fabricated with a castor oil based polyurethane resin. Among the factors, only the seal coating was statistically significant. The wood panels of Treatment 2 were classified as H1, based on the internal bond strength and elastic modulus results data required by ANSI A208.1:1999. The bending strength data did not reach the minimum values recommended by NBR 14810:2006 and ANSI A208.1:1999. The thickness swelling data for 2h immersed in water achieved the standard requirement levels. High-density panels were achieved revealing their potential use in variety of particleboard applications.

Keywords: BOPP, mechanical properties, particleboards, physical properties

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Authors: K. Akhil, J. Jayakumar, S. Sudheer Khan

Abstract:

Zinc oxide nanoparticles (ZnO NPs) are extensively used in a wide variety of commercial products including sunscreen, textile and paints. The present study evaluated the effect of surface capping agents including polyethylene glycol (EG), gelatin, polyvinyl alcohol(PVA) and poly vinyl pyrrolidone(PVP) on photocatalytic activity of ZnO NPs. The particles were also tested for its antibacterial and antibiofilm activity against Staphylococcus aureus (MTCC 3160) and Pseudomonas aeruginosa (MTCC 1688). Preliminary characterization was done by UV-Visible spectroscopy. Electron microscopic analysis showed that the particles were hexagonal in shape. The hydrodynamic size distribution was analyzed by using dynamic light scattering method and crystalline nature was determined by X-Ray diffraction method.

Keywords: antibacterial, antibiofilm, capping agents, photodegradation, surface coating, zinc oxide nanoparticles

Procedia PDF Downloads 267

Authors: C. S Lee, W. C. Hsu, H. Y. Liu, C. J. Lin, S. C. Yao, Y. T. Shen, Y. C. Lin

Abstract:

In₀.₁₈Al₀.₈₂N/AlN/GaN metal-oxide-semiconductor heterostructure field-effect transistors (MOS-HFETs) having Al₂O₃ gate-dielectric and backside metal-trench structure are investigated. The Al₂O₃ gate oxide was formed by using a cost-effective non-vacuum ultrasonic spray pyrolysis deposition (USPD) method. In order to enhance the heat dissipation efficiency, metal trenches were etched 3-µm deep and evaporated with a 150-nm thick Ni film on the backside of the Si substrate. The present In₀.₁₈Al₀.₈₂N/AlN/GaN MOS-HFET (Schottky-gate HFET) has demonstrated improved maximum drain-source current density (IDS, max) of 1.08 (0.86) A/mm at VDS = 8 V, gate-voltage swing (GVS) of 4 (2) V, on/off-current ratio (Ion/Ioff) of 8.9 × 10⁸ (7.4 × 10⁴), subthreshold swing (SS) of 140 (244) mV/dec, two-terminal off-state gate-drain breakdown voltage (BVGD) of -191.1 (-173.8) V, turn-on voltage (Von) of 4.2 (1.2) V, and three-terminal on-state drain-source breakdown voltage (BVDS) of 155.9 (98.5) V. Enhanced power performances, including saturated output power (Pout) of 27.9 (21.5) dBm, power gain (Gₐ) of 20.3 (15.5) dB, and power-added efficiency (PAE) of 44.3% (34.8%), are obtained. Superior breakdown and RF power performances are achieved. The present In₀.₁₈Al₀.₈₂N/AlN/GaN MOS-HFET design with backside metal-trench is advantageous for high-power circuit applications.

Keywords: backside metal-trench, InAlN/AlN/GaN, MOS-HFET, non-vacuum ultrasonic spray pyrolysis deposition

Procedia PDF Downloads 252

Authors: Nasir Mustafa

Abstract:

One of the prerequisites required for an efficient diagnosis in a medical practice is to have a strong command of both functional and clinical anatomy. In this study, we introduce a new collaborative approach to the effective teaching of the knee and hip joints. In the present teaching model, anatomists, orthopedists and physical therapists present the anatomy of the hip and knee joints in small groups. Courses for the hip and knee joints were scheduled during the early stages of the medical curriculum. Students of nursing and physical therapy were grouped together to sensitize to the importance of a collaborative effort. The study results clearly demonstrate that nursing students and physical therapy students appreciated this teaching approach. The collaborative approach further proved to be a suitable method to teach both functional and clinical anatomy of the hip and knee joints. Aside from this training, a collaborative approach between medical students and physical therapy students was also successful for a healthcare organization.

Keywords: hip and knee joint anatomy, collaborative, Anatomy teaching, Nursing students, Physiotherapy students

Procedia PDF Downloads 87

Authors: S. Mohammadzadehmoghadam, Y. Dong

Abstract:

In this study, Bombyx mori silk fibroin/gelatin (SF/GT) nanocomposite with different GT ratio (SF/GT 100/0, 90/10 and 70/30) were prepared by electrospinning process and crosslinked with glutaraldehyde (GA) vapor. Properties of crosslinked SF/GT nanocomposites were investigated by scanning electron microscopy (SEM), mechanical test, water uptake capacity (WUC) and porosity. From SEM images, it was found that fiber diameter increased as GT content increased. The results of mechanical test indicated that the SF/GT 70/30 nanocomposites had both the highest Young’s modulus of 342 MPa and the highest tensile strength of about 14 MPa. However, porosity and WUC decreased from 62% and 405% for pristine SF to 47% and 232% for SF/GT 70/30, respectively. This behavior can be related to higher degree of crosslinking as GT ratio increased which altered the structure and physical properties of scaffolds. This study showed that incorporation of GT into SF nanofibers can enhance mechanical properties of resultant nanocomposite, but the GA treatment should be optimized to control and fine-tune other properties to warrant their biomedical application.

Keywords: electrospinning, gelatin, silk fibroin, mechanical properties, nanocomposites

Procedia PDF Downloads 148

Authors: Osama Terra, Hatem Hussein

Abstract:

Calibration of Optical Time Domain Reflectometer (OTDR) is crucial for the accurate determination of loss budget for long optical fiber links. In this paper, the calibration of the attenuation scale of an OTDR using two different techniques is discussed and implemented. The first technique is the external modulation method (EM). A setup is proposed to calibrate an OTDR over a dynamic range of around 15 dB based on the EM method. Afterwards, the OTDR is calibrated using two standard reference fibers (SRF). Both SRF are calibrated using cut-back technique; one of them is calibrated at our home institute (the National Institute of Standards – NIS) while the other at the National Physical Laboratory (NPL) of the United Kingdom to confirm our results. In addition, the parameters contributing the calibration uncertainty are thoroughly investigated. Although the EM method has several advantages over the SRF method, the uncertainties in the SRF method is found to surpass that of the EM method.

Keywords: optical time domain reflectometer, fiber attenuation measurement, OTDR calibration, external source method

Procedia PDF Downloads 461