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Abstract

In this study, the mineralogical content of Abu Rusheid mylonite sample was investigated and revealed that the sample is essentially composed of quartz and feldspar (72.14% mass), muscovite (16.6% mass), and contains heavy economic polymetallic minerals of about 2.65% by mass. By studying the differences in the physical properties of this mineral content, a proposed flow sheet was set up to explain the successive physical upgrading steps for concentrating and separating the valuable minerals content and getting rid of the associated gangue minerals. Industrial, economic and strategic polymetallic minerals were identified at Abu Rusheid mylonite sample, including cassiterite, titanite, brass, kasolite, monazite, and uranothorite. A group of sulfide minerals also existed as pyrite, arsenopyrite, galena, and molybdenite in addition to the presence of fluorite and iron oxides bearing rare earth elements (REEs) and base metals. Using dry high intensity magnetic separation followed by wet gravity separation and flotation, three concentrates were obtained; heavy paramagnetic concentrate (monazite, columbite, brass, and jarosite), heavy diamagnetic concentrate (zircon, kasolite, uranothorite, cassiterite, and sulphide minerals) and muscovite concentrate for industrial uses. Physical processing of Abu Rusheid mylonite sample was carried out to produce high grade mineral concentrate used as a raw material for chemical treatment to extract economic elements that necessary for several industries.

Open access

Abstract

A total of 46 Staphylococcus aureus isolates from fish and ground beef were tested for the agr types, icaABCD genes, and biofilm formation at 12, 25 and 37 °C by the microtiter plate and the MTT assays. All isolates were positive for the icaABD genes, while 97.8% were positive for the icaC. All isolates produced biofilms at 37 and 25 °C, but 93.5% of them were also biofilm producers at 12 °C. There was no significant difference in biofilm formation between 25 and 37 °C using the crystal violet assay (P > 0.05). However, statistically significant differences were detected between 12 and 25 °C as well as 12 and 37 °C (P < 0.05). All isolates were significantly different in biofilm production by the MTT assay at all tested temperatures. Furthermore, a relationship between the presence of the icaABCD genes and biofilm formation was observed. The agr type I was the most prevalent (54.4%) among the isolates, followed by agr type II (41.3%) and agr type III (9.6%). In this study, the S. aureus isolates exhibited biofilm formation ability responsible for persistence of bacteria in foods, which may lead to food spoilage and human health problems.

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Abstract

Previously isolated Pseudomonas lundensis CP-P-5 had antagonistic activity against Salmonella Hartford, Yersinia enterocolitica, and Escherichia coli. In this study, determination of its antagonistic mechanism and potential field of application in food industry was aimed. Using cellophane-test and microcultures of the test strain's cell-free supernatant mixed with the pathogens, our results showed that cells of P. lundensis CP-P-5 and its concentrated cell-free supernatants were effective against the foodborne bacteria, and the supernatants contained more than one compound responsible for inhibitory activity. Searching for the antagonistic compound, NaOH, protease, and heat treatments were done to the supernatants, and proteolytic activity and siderophore production were also tested using the antagonistic strain. Our results support the potential applicability of P. lundensis CP-P-5 as a bioprotective agent against foodborne pathogens in food processing environments.

Open access

Abstract

Most applications in engineering use a data acquisition device hooked up to a personal computer for data processing. Finding less costly, easily accessible and reliable devices will make personal computer (PC) based data acquisition systems less difficult. A soundcard may be used as such a device for it is standard in almost every PC. It can also process any voltage signal within its limits. This paper proposes a way to enable the PC to be used as an oscilloscope. A voltage signal is acquired via the soundcard LINE IN port. The maximum and minimum input signal amplitude requirements for the soundcard are established to be +1 V and –1 V respectively. Based on these findings, hardware circuitry is designed to clip any high amplitude input signals to the range of ±1 V while allowing low amplitude signals to go through to the soundcard unclipped. MATLAB is then employed to acquire, process and display the signal. The final output from MATLAB is compared with the original signal to determine accuracy of the designed oscilloscope. Analysis of the results obtained shows that the final oscilloscope designed enables the soundcard to process input signals with a high level of accuracy. The final design yields a hardware cost at a fraction of an iPod while providing an elegant user interface. This makes it suitable for college students, basement hackers and even professional engineers.

Open access

Abstract

The study aims to examine the effects of palm biodiesel blended with additives in the compression ignition (CI) engine. Biodiesel as fuel was limited by challenges such as lower calorific value (CV) and higher viscosity while increasing brake specific fuel consumption (BSFC) and nitrogen oxides (NOx) emissions. Nanoparticles and antioxidant additives added to biodiesel play an essential role in avoiding the hindrances of biodiesel. The antioxidants combined with biodiesel reduced NOx emissions by eliminating decomposing peroxides, free radicals, and preventing free radicals' chain reaction. The Significant characteristics of nanoparticles are high CV, high thermal conductivity, and higher surface to volume ratio. These characteristics are used to improve the CI engine's performance and emissions by using nanoparticles blended with biodiesel. Five different test blends of Diesel, B20, B20TO, B20AO, and B20AOTO were prepared. The result showed high brake thermal efficiency (BTHE) and decreased BSFC, exhaust gas temperature (EGT), hydrocarbons (HC), NOx, and HC emissions by using the B20AOTO fuel blend contrasted with other biodiesel blends.

Open access

Abstract

The present study emphasised the efficiency of chitosan anchored titanium dioxide nano-adsorbent on dairy industry effluent treatment. Chitosan titanium dioxide nano-adsorbent was synthesised by using chemical precipitation method and characterised for its particle size, surface morphology and texture. A four-factor-three-level Box–Behnken design along with response surface methodology was used to optimise the adsorption process parameters. Linear, two factor interaction, quadratic and cubic model techniques were used to demonstrate the influence of each parameter and their interaction effects on the responses. The quadratic models derived from the experimental data were used to predict the maximum per cent reduction of biological oxygen demand (BOD) and chemical oxygen demand (COD). The optimised treatment combination for maximum per cent reduction in BOD (90.48%) and COD (82.10%) was found to be initial concentration of 100 mg L−1, pH of 7, dosage of 1.25 mg L−1 and contact time of 100 min.

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Pollack Periodica
Authors: Ali Kareem Abdulrazzaq, György Bognár, and Balázs Plesz

Abstract

This paper presents a combined electro-thermal model to serve the aim of accurate output power prediction of photovoltaic systems, based on the concept of the thermal energy balance. The electrical sub-model is built based on fitting a surface to the current-voltage curves collected under wide range temperatures and irradiances. For this purpose, the current-voltage characteristic curves are reproduced using two different methods. The thermal sub-model considers all the effective heat transfer mechanisms to estimate the photovoltaic module junction temperature. The Newton-Raphson iterative method is used as a solving algorithm to calculate the photovoltaic junction temperature. The collected results prove the applicability of the model under a wide range of environmental conditions.

Open access

Abstract

In embedded systems that necessarily require a steady source of power and (or) attaches to a sensor(s), there are opportunities to mix small batteries to supply such power. The aim of this research is to optimize the geometry and shape of piezoelectric cantilevers to harvest more power. Several piezoelectric cantilever geometries with various shapes (rectangular, triangular, circular, and trapezoidal cross section) are tested in COMSOL multiphysics simulator to find the best geometry that provides the highest accomplishable power. The most efficient geometry was found to be conferred by the trapezoidal, cross section cantilever. Next, another improvement method was applied to maximize the harvested power of the cantilever by modifying the shape of the trapezoidal cantilever structure through increasing the number of its faces. The results demonstrated that the highest output power (36 mW) was produced by the four faces, trapezoidal cross section design of cantilever.

Open access

Abstract

In this paper the generalized model of contact of two plan bodies that roll and slide or just roll is presented. The analytical solution of the correct distribution of pressure in the contact is realized in the presence of the normal compressive force, which realizes the contact, as well as of the force pair or of a tangential force. This model can be used on sprocket teeth due to sliding rolling or rolling itself on the gear pole. The results obtained have been experimentally confirmed by many researchers as well as by the damage that the wheels actually suffer from the teeth.

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Abstract

The behavior of box-shaped columns under heating is investigated. For this purpose, the various sections of thin-wall box-shaped columns were modeled and verified in different temperature ranges by ABAQUS software. The results of this research showed that increasing the thickness leads to increase the buckling stability of column under temperature change. Since the behavior of column will be better than thinner columns under climate change because of the increase in the modulus of elasticity. The solid columns have better buckling stability than hollow columns in normal conditions.

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