Search

The study describes the successful development of a TiO2 ceramic substrate with a protective nano-Al2O3 coating using two different coating techniques: microwave combustion and polymeric methods. The coated ceramics demonstrate enhanced corrosion resistance compared to the uncoated substrate. The optimal TiO2 substrate was prepared by firing it at 1000 °C. This was done to give the desired physical properties of the TiO2 substrate for the coating procedures. Nano-Al2O3 powder was coated onto the surface of the TiO2 substrates. The TiO2 substrates with the Al2O3 coating were then calcined (heat-treated) at 800 and 1000 °C. The structures, morphology, phase composition, apparent porosity, bulk density, and compressive strength of the substrate and coated substrate were characterized. Upon firing at 1000 °C, it was discovered that the two phases of TiO2—rutile and anatase—combine in the substrate. Once the substrate has been coated with nano Al2O3 at 1000 °C, the anatase is transferred into rutile. When compared to the substrate, the coated substrate resulted in a decrease in porosity and an increase in strength. The efficiency of the ceramic metal nanoparticles Al2O3 as a good coating material to protect the TiO2 substrates against the effect of the corrosive medium 0.5 M solution of H2SO4 was measured by two methods: potentio-dynamic polarization (PDP) and the electrochemical impedance spectroscopy (EIS). The results indicated that the corrosion rate was decreased after the substrate coated with alumina from (67.71 to 16.30 C.R. mm/year) and the percentage of the inhibition efficiency recorded a high value reaching (78.56%). The surface morphology and composition after electrochemical measurements are investigated using SEM and EDX analysis. After conducting the corrosion tests and all the characterization, the results indicated that the coated TiO2 substrate prepared by the polymeric method at 800 °C displayed the best physical, mechanical, and corrosion-resistant behavior. [ABSTRACT FROM AUTHOR]

This study focuses on recycling of granite sludge for production of cordierite-spinel composites prepared by direct coagulation method. Furthermore, the effect of transition metal oxides (CuO, NiO, and MnO2) on their in-situ formation, sinterability and properties (mechanical and electrical) was studied. The granite sludge, talc, and calcined alumina were utilized to prepare cordierite-spinel composites. Firstly, talc and alumina were mixed and fired at 1350 °C, then mixed with granite sludge and transition metal oxides to be ready for casting by direct coagulation method after adjusting the appropriate conditions. The casted specimens were firstly dried then sintered at 1200 and 1250 °C. The phase composition and physical properties of sintered composites were investigated by x-ray diffraction technique (XRD) and Archimedes method, respectively. The microstructure was investigated by scanning electron microscope while the hardness was tested by Vickers indentation method. The electrical properties of sintered bodies were also evaluated. All XRD patterns showed formation of cordierite and spinel phases after addition of metal oxides and sintering at 1200 or 1250 °C. Also, the results indicated enhancement of densification parameters for CuO- and MnO2-containing composites after sintering at 1250 °C while for NiO-containing composites, they enhanced after sintering at 1200 °C. Furthermore, the densification parameters were improved with increasing metal oxides contents. The highest hardness value (8.3 GPa) was obtained for 6% NiO-containing composite. The composites that contained 6 wt.% CuO or MnO2 exhibited hardness values of 6.4 and 6.16 GPa, respectively. The trend of electrical conductivity values for sintered composites was as follows: CuO-containing composite > NiO-containing composite > MnO2-containing composites. [ABSTRACT FROM AUTHOR]

The present work focused on recycling the alum sludge which is one of the serious problems during the production of potable water. In this work, the alumina was extracted from alum sludge by using different chemical treatment methods after subjecting to different thermal treatments. XRD, XRF, SEM, TEM, IR and surface area measurements were used to detect the properties of the obtained alumina. Alpha alumina was obtained at 1400°C after treatment by NaOH followed by ammonium acetate as a precipitating agent for Al(OH)3 or by direct addition of NH4OH in one step method at pH 5.5–6. On the contrary, the treatment by NaOH followed by NaHCO3 for precipitation of Al(OH)3 led to the formation of sodium aluminate beside low percentage of alpha alumina after the heat treatment. [ABSTRACT FROM AUTHOR]

In the present day, water treatment has emerged as a significant global concern, particularly due to the proliferation of pollution sources. The utilization of dyes, such as Evans blue, in several industries is among the most significant contributors to these pollutants. Forsterite nanoparticles were synthesized by the sol-gel technique and calcined at different temperatures to determine the optimum temperature at which pure nanoforsterite was obtained. Then, it was analyzed using X-ray diffraction (XRD), atomic force microscope (AFM), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET) , contact angle, and zero-point charge. The adsorption capability of forsterite nanoparticles (Nps) was evaluated by a batch adsorption experimental method to remove Evans blue dye (EBD). Parameters such as agitation speed, dosage of forsterite Nps, pH, and contact time were considered at ambient temperature. At pH = 3, dose of Nps = 1 g/L, and 600 rpm within 10 min, the results indicated a removal rate of around 100%. Furthermore, it was shown that the material may be employed for 3 cycles with a removal rate of 90%. Multiple kinetic and isotherm models, including Langmuir, Temkin, and Freundlich models, were used to analyze the results and clarify the mechanism of the adsorption phenomena. The findings from the isotherm and kinetic studies indicated that the system conforms to Langmuir and pseudo-second-order, respectively. [ABSTRACT FROM AUTHOR]

The preservation of post-harvest storage products, such as grains and rice, is often plagued by insect pests, with the rice weevil (Sitophilus oryzae L.) standing out as important. This study evaluates the efficacy of spice extracts of Syzygium aromaticum, Trigonella foenum-graecum and Ferula assa-foetida against S. oryzae at varying concentrations. Extracts exhibited toxicity that inhibited egg development and larval progression, with deformations observed at lower concentrations leading to larval death at higher concentrations. Qualitative and quantitative assessment of insect α-amylase activity revealed significant decreased activity with prolonged exposure. The study demonstrated increasing mortality rates with the combined spice extracts displaying the highest efficacy followed by S. aromaticum, T. foenum-graecum, and F. assa-foetida extracts, indicating promising insecticidal activity against S. oryzae. [ABSTRACT FROM AUTHOR]

This study was designed to deduce the effect of parity and calving season on the resumption of ovarian cyclicity in post-partum Murrah buffaloes. For this study, 102 Murrah buffaloes (primparous: 21; pluriparous: 81) calved between August 2015 and February 2016 were examined by transrectal ultrasonography. The first group of buffaloes between 26- days post-partum were taken and thereafter animals calved every next 10 days were grouped and added. Animals thus progressed and adjudged in 26-35, 36-45, 46-55, 56-65, 66-75, 76-85 and 86-95 days post-partum with an average of 30, 40, 50, 60, 70, 80 and 90 days post-partum, respectively. The day of second examination at 10 days interval of first group of animals also had first examination of second group and the same was followed for all study groups till cyclicity was confirmed in all study animals. In this investigation, 40.20, 65.69 and 81.37 % buffaloes resumed cyclicity within 30, 60 and 90 days post-partum, respectively. Significant (p < 0.0001) difference in resumption of cyclicity between primiparous and pluriparous buffaloes was observed. Onset of cyclicity in pluriparous buffaloes (37.24 ± 1.83 days post-partum) differed significantly (p = 0.0001) than primiparous (59.61 ± 6.10 days post-partum). Also, the onset of cyclicity was evident (p < 0.0001) during pre-breeding (n = 60) and resumption of ovarian cyclicity showed a significant trend (p < 0.0001) in relation to days post-partum. In summary, resumption of ovarian cyclicity differs significantly with parity and season of calving in post-partum Murrah buffaloes. [ABSTRACT FROM AUTHOR]

Ceramic materials account for the largest percentage of waste generated in the construction and demolition of concrete structures. Currently, this ceramic waste is disposed of in landfills, due to the lack of alternative disposal options and the lack of awareness of options for the reuse of these materials. This study aims to identify the existing alternatives and establish the potential for the reuse and valorization of ceramic waste. This analysis of alternatives for the reuse and valorization of ceramic waste is carried out through a bibliographic review focused on identifying the existing options for the reuse and valorization of ceramic waste. For each existing alternative, a brief description of the methodology used is made and the main results achieved in each study are highlighted. Based on the bibliographic review, some alternatives for the reuse of ceramic materials are presented. It was established that ceramic waste is currently used mainly in the formulation of concrete, manufacture of electrical insulators, extraction of alumina, and as a geological barrier to contain nuclear waste. In addition, based on the properties of ceramic materials, it was concluded that the potential applications for reuse include obtaining thermal insulators, abrasive materials, coral reef regeneration, and the elaboration of structures using additive manufacturing techniques. It was found that the most economically profitable option for the reuse and valorization of ceramic waste is the manufacture of concrete, while the most viable option is the manufacture of abrasive materials. [ABSTRACT FROM AUTHOR]

The unsustainable use of resources and the rising demand for traditional concrete have disrupted ecological equilibrium, necessitating the adoption of a more appropriate and long-lasting alternative. One such substitute for cement in concrete production is geopolymer concrete, although this material is prone to cracking and fracturing due to its low tensile strength, leading to costly repairs or even structural collapse. Fiber-reinforced concrete has recently been widely adopted as a construction material to counteract these issues. This research examined the crack proliferation and fracture toughness of geopolymer concrete comprising different fibers using a cracked Brazilian disc. Four different fibers were used, such as polypropylene and steel fiber (short and long), at a dosage of 1.5% by volume. Fracture toughness was computed for various modes (I, II, and I/II) of fractures, and crack propagation from cracked specimens was studied. A different angle of inclination (0, 15, 28, 83, 60, 75, and 90 degrees) was used to conduct the Brazilian disc test on the specimens with respect to the preexisting crack direction. The findings indicate that the increasing loading angle increased the load-carrying capacity. The fracture toughness values of specimens under all three modes ranged from 0.26 to 1.75 MPa.m1/2. Additionally, long polypropylene and steel fibers exhibit higher fracture toughness than short fibers. [ABSTRACT FROM AUTHOR]

To avoid the potential risks associated with all hazardous wastes, it is important that containment methods are intended to prevent the migration of liquid hazardous wastes or leaks containing hazardous components. Therefore, impermeable barriers were used to prevent contamination. In this study, geotechnical tests were performed on samples by mixing rubber and bentonite with silica fume at certain percentages. The aim of the experimental studies is to evaluate the applicability of certain proportions of silica fume, rubber, and bentonite mixtures as impermeable liner material. Possible cracks in bentonite during drying are reduced by the use of silica fume. Absorption of dynamic effects that may occur on the impermeable barrier layer is achieved by adding waste rubber in a uniform size. Several geotechnical tests were performed to examine the mixed rubber and bentonite with silica fumes. Looking at the results of the whole that mixed rubber and bentonite with silica fume yielded usable results and a blend for construction of a liner. [ABSTRACT FROM AUTHOR]

Clay stability in water is essential in chemical and manufacturing processes. In water based drilling fluids, montmorillonite dispersed in water is commonly used to maintain fluid density that counter-balances pressure effects from formation layers. However, due to gravity, clay particles settlement at the bottom of holes is inevitable especially if operations in holes are suspended for technical reasons such as during fishing operations and dislodging of stuck pipes. This necessitates the introduction of additives that can enhance dispersion of clay particles in water columns. It has been reported that some nanoparticles can enhance clay stability in water; hence the primary objective in this work is to identify nanoparticles that have potentials to enhance clay stability and nanoparticles that promote clay instability in distilled water and brine of 30 g/l. In the experimental work, clays and different kinds of nanoparticles were dispersed in columns of water and the volumes of settled particles were plotted against time. Experimental results show that nanoparticles of silicon, zirconium, iron, tin, nickel and magnesium oxides all have the capacity to improve clay stability in water, while the presence of Al2O3 and ZnO nanoparticles promote clays instability in water. It is therefore recommended that further research on desirable drilling fluid properties be conducted with nanoparticle oxides that promote clay stability in water to investigate their suitability as additives in water based drilling muds. [ABSTRACT FROM AUTHOR]

Buffaloes are raised by small farm holders primarily as source of draft power owing to its resistance to hot climate, disease, and stress conditions. Over the years, transformation of these animals from draft to dairy was deliberately carried out through genetic improvement program leading to the development of buffalo-based enterprises. Buffalo production is now getting more attention and interest from buffalo raisers due to its socioeconomic impact as well as its contribution to propelling the livestock industry in many developing countries. Reproduction of buffaloes, however, is confronted with huge challenge and concern as being generally less efficient to reproduce compared with cattle due to both intrinsic and extrinsic factors such as poor estrus manifestation, silent heat, marked seasonal infertility, postpartum anestrus, long calving interval, delayed puberty, inherently low number of primordial follicles in their ovaries, high incidence of atresia, and apoptosis. Assisted reproductive technologies (ARTs) are major interventions for the efficient utilization of follicle reserve in buffaloes. The present review focuses on estrus and ovulation synchronization for fixed time artificial insemination, in vitro embryo production, intracytoplasmic sperm injection, cryopreservation of oocytes and embryos, somatic cell nuclear transfer, the factors affecting utilization in various ARTs, and future perspectives in buffaloes. [ABSTRACT FROM AUTHOR]

Ceramic composites based on alumina and zirconia have found a wide field of application in the present century in orthopedic joint replacements, and their use in dentistry is spreading. The development of this class of bioceramic composites was started in the 1980s, but the first clinical applications of the total hip replacement joint were introduced in the market only in the early 2000s. Since then, several composite systems were introduced in joint replacements. These materials are classified as Zirconia-Toughened Alumina if alumina is the main component or as Alumina-Toughened Zirconia when zirconia is the main component. In addition, some of them may contain a third phase based on strontium exa-aluminate. The flexibility in device design due to the excellent mechanical behavior of this class of bioceramics results in a number of innovative devices for joint replacements in the hip, the knee, and the shoulder, as well in dental implants. This paper gives an overview of the different materials available and on orthopedic and dental devices made out of oxide bioceramic composites today on the market or under development. [ABSTRACT FROM AUTHOR]

The quality of water is of the utmost importance and vital concern for the human beings since it has a direct link with the human health and welfare. If the drinking water or tap water gets contaminated, it can result in severe health problems. For example, if the drinking water contains over the limit amount of fluoride then it can lead to bone deterioration and other bone related problems. The purpose of the present study is to carry out quality analysis of drinking and tap water in Nawabshah City. The analyzed parameters are pH, TDS, Total Alkalinity, Total Hardness, Calcium Hardness and Electrical Conductivity. World Health Organization (WHO) standards are followed in the present study. Total 18 drinking water and tap water samples were collected from 6 different locations in Nawabshah City. The parameters that appeared to be within the limits are PH and total alkalinity whereas TDS, total hardness, calcium hardness and electrical conductivity crossed WHO standard limits at some locations. [ABSTRACT FROM AUTHOR]

To improve the performance and increase the lifetime of oil‐filled transformers, the thermal and dielectric properties of the transformer oil should be enhanced. Recently, nanotechnology was used as an effective science in the field of transformer oil development. In this study, barium titanate (BT) nanoparticles were inserted into the base transformer oil by a concentration of 0.005 g/L as an individual nanofluid sample (INFS). This insertion enhances the heat transfer coefficient by 33% but the breakdown voltage (BDV) was decreased by >10%. To overcome this problem of dielectric properties degradation, other three hybrid nanofluid samples (HNFS) were prepared using three different types of metal oxide (MO) nanoparticles; titania, alumina, and silica. These samples were prepared by adding a concentration 0.01 g/L of MO nanoparticles together with 0.005 g/L of BT nanoparticles into the oil. The thermal and dielectric properties of HNFS were measured to study the behaviour of nanoparticles hybridisation on transformer oil properties. HNFS using titania nanoparticles provided the best composition regarding either BDV or heat transfer coefficient. Dynamic light scattering (DLS) technique was used to evaluate the particle size distribution of hybrid nanoparticles and to clarify the corresponding physical mechanisms behind the obtained enhancement. [ABSTRACT FROM AUTHOR]

In this research, the rheological behavior and stability of suspensions containing Si3N4, Al2O3, Y2O3 and starch were investigated in order to use them in the starch consolidation casting of porous silicon nitride. Dolapix CE64 was used as the dispersant. Then, the effect of some parameters such as Si3N4 surface oxidation, dispersant content, solid loading and starch content on the viscosity and rheological behavior of Si3N4-starch slurry was determined. Surface oxidation of Si3N4 powder at 800C for 2 hours reduced the viscosity of the slurry, effectively. The best dispersant content was 0.4 wt. %, relative to ceramic powders. Slurries containing 30 to 40 vol. % and 7.5 to 25 vol. % starch, relative to total solid loading, had the suitable viscosity and the sufficient stability for casting by the starch consolidation method. [ABSTRACT FROM AUTHOR]

In this research paper, the solar irradiance of flat plate solar collector was evaluated using experimental and numerical analysis. In the experiment, an automatic solar simulator was designed and built to simulate the solar irradiance. The simulator was controlled by an Arduino board. The light source and fabrication of the simulator were used for a wide range of testing and the comparison was made between different cases. The test was performed on a flat plate double glazing solar collector with different base fluids; ethylene glycol (EG), glycerine, and water. To enhance the heat transfer, Al2O3 nanoparticles having a diameter of 20 nm were added. In order to investigate the effect of volume fraction on the heat absorption, three-volume fractions, 0.2%, 0.45, and 0.6%, were used in this study. Laminar flow was considered with a flow rate of 1 L/min. Solar irradiance was measured from 11:00 to 13:00 on September 25th, 2016. COMSOL 5.2a was used in a numerical analysis of flat plate solar collector. A good agreement between numerical and experimental for all cases was observed. The maximum temperature difference between inlet and outlet was found when the (water/ Al2O3) was used as a working fluid at a volume fraction of 0.6%. [ABSTRACT FROM AUTHOR]

Rapeseed (RS) is an abundant and inexpensive source of energy and AA in diets for monogastrics and a sustainable alternative to soybean meal. It also contains diverse bioactive phytochemicals that could have antinutritional effects at high dose. When the RS-derived feed ingredients (RSF) are used in swine diets, the uptake of these nutrients and phytochemicals is expected to affect the metabolic system. In this study, 2 groups of young pigs (17.8 ± 2.7 kg initial BW) were equally fed a soybean meal-based control diet and an RSF-based diet, respectively, for 3 wk. Digesta, liver, and serum samples from these pigs were examined by liquid chromatography-mass spectrometry-based metabolomic analysis to determine the metabolic effects of the 2 diets. Analyses of digesta samples revealed that sinapine, sinapic acid, and gluconapin were robust exposure markers of RS. The distribution of free AA along the intestine of RSF pigs was consistent with the reduced apparent ileal digestibility of AA observed in these pigs. Despite its higher fiber content, the RSF diet did not affect microbial metabolites in the digesta, including short-chain fatty acids and secondary bile acids. Analyses of the liver and serum samples revealed that RSF altered the levels of AA metabolites involved in the urea cycle and 1-carbon metabolism. More importantly, RSF increased the levels of multiple oxidized metabolites and aldehydes while decreased the levels of ascorbic acid and docosahexaenoic acid-containing lipids in the liver and serum, suggesting that RSF could disrupt redox balance in young pigs. Overall, the results indicated that RSF elicited diverse metabolic events in young pigs through its influences on nutrient and antioxidant metabolism, which might affect the performance and health in long-term feeding and also provide the venues for nutritional and processing interventions to improve the utilization of RSF in pigs. [ABSTRACT FROM AUTHOR]

Brassica napus and Brassica juncea canola meal (CM) may replace soybean meal (SBM) in pig diets, but differ in fiber, glucosinolates content and profile. Preference of weaned pigs provided double-choice selections to diets containing 20% SBM, B. napus CM, or B. juncea CM was evaluated in two studies. In experiment 1, 216 pigs (9.4 ± 1.6 kg initial BW) were housed in 27 pens of 8 pigs (four gilts and four barrows). In experiment 2, 144 pigs (8.9 ± 1.1 kg) were housed in 36 pens of 4 pigs (two gilts and two barrows). Pigs were offered three dietary choices: B. napus CM with SBM as reference (B. napus CM [SBM]), B. juncea CM with SBM as reference (B. juncea CM [SBM]), and B. juncea CM with B. napus CM as reference (B. juncea CM [B. napus CM]) in a replicated 3 × 3 Latin square. Diets were formulated to provide 2.4 Mcal NE/kg and 4.5 g standardized ileal digestible Lys/Mcal NE and were balanced using canola oil and crystalline AA. Each pair of diets was offered in two self-feeders per pen as mash (experiment 1) or pellets (experiment 2) during three test-periods of 4-d, followed by a 3-d non-test period when a common diet was offered in both feeders. Feeders with different diets were rotated daily among pens during preference periods for both experiments, and feeder positions (right or left) were switched daily in experiment 2. Prior to the study and between periods, pigs were fed non-test diets containing SBM (experiment 1) or without test feedstuffs (experiment 2). Overall in both experiments, pigs preferred (P < 0.001) SBM over B. napus and B. juncea CM diets, and preferred (P < 0.001) B. napus over B. juncea CM diet. Dietary choice did not affect (P > 0.05) growth performance in both experiments, except for greater G:F (P < 0.05) for pigs fed the B. juncea CM [B. napus CM] diets than pigs fed the B. napus CM [SBM] or B. juncea CM [SBM] diets in experiment 1. In conclusion, weaned pigs preferred SBM over CM diets when given a choice, and preferred B. napus over the B. juncea diet that contained more total glucosinolates especially gluconapin. Weaned pigs fed the B. juncea CM [B. napus CM] diets in the double-choice selection did not reduce feed intake, weight gain, and G:F compared to pigs fed the B. napus CM [SBM] or B. juncea CM [SBM] diets. [ABSTRACT FROM AUTHOR]

The main goal of the present investigation was to the synthesis of bioactive TiO2 nanoparticle-incorporated poly(methylmethacrylate)/polyetheretherketone nanocomposite for enhanced antibacterial and biocompatibility characteristics with suitable properties for manufacturing 3D printed stereolitographic dental prosthesis. The carboxylic acid-functionalized TiO2 nanoparticles have been dispersed into the copolymer matrixes through emulsion polymerization method, and the structural and morphological properties were investigated by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy, and energy dispersive X-ray (EDX) analytical techniques. The FTIR spectrum of synthesized nanocomposites that shows high intense peaks at 2,970-2,850 cm−1 is related to the symmetric and asymmetric stretching C-H vibration of methyl and methylene groups of the polymer matrix. The microscopic results of nanocomposite exhibited that functionalized nanoparticles were effectively and uniformly dispersed into the polymer matrix in the absence of particle agglomerations, and it has been given excellent killing efficiency of 99% under dark conditions against bacterial pathogens Escherichia coli and Staphylococcus aureus and also exhibited favorable cell compatibility with dental pulp cells. This facile synthesized nanocomposite was efficaciously employed for denture manufacturing with stereolitographic technique. [ABSTRACT FROM AUTHOR]

Studying the effect of adding nanosized ZrO2 to mineral transformer oil on the AC breakdown voltage is presented. The study is carried out considering different concentration levels of nanosized ZrO2. These concentrations are 0, 0.001, 0.002, 0.003 and 0.006%w. The AC breakdown voltage of both nanofilled and base oil is measured according ASTM D1816 standard at room temperature. The evaluation is carried out based on AC breakdown voltage for the nanofilled and base oil considering average and Weibull statistical techniques. Both 50 and 10% breakdown voltage probabilities are obtained and analysed for all samples. Also, the effect of temperature (to take the effect of real operating conditions) on breakdown voltage of base and nanofilled oil is experimentally evaluated. The studied temperatures are 50, 80 and 130°C. The obtained results show that the performance of nanoparticles is significantly affected by increasing the temperature of nanofilled transformer oil. Finally, a proposed mechanism for the effect of temperature on the nanofluids breakdown strength is introduced. [ABSTRACT FROM AUTHOR]

This study presents theoretical as well as experimental studies in order to obtain interpretations about the role of nanoparticles in the breakdown mechanism of transformer oil. The published breakdown mechanisms for nanofilled transformer oil are briefly discussed in order to highlight the points of agreement and disagreement with these mechanisms. Moreover, a proposed breakdown mechanism for nanofilled oil is presented depending on a proposed particle charging mechanism that is theoretically discussed and experimentally validated. Finally, the obtained experimental results prove the efficacy of the proposed theoretical mechanisms. [ABSTRACT FROM AUTHOR]

Presents the 2015 author/subject index for this publication. [ABSTRACT FROM AUTHOR]

The Red Sea possesses a unique geography, and its shores are rich in mangrove, macro-algal and coral reef ecosystems. Various sources of pollution affect Red Sea biota, including microbial life. We assessed the effects of industrialization on microbes along the Egyptian Red Sea coast at eight coastal sites and two lakes. The bacterial communities of sediment samples were analyzed using bacterial 16S rDNA pyrosequencing of V6-V4 hypervariable regions. The taxonomic assignment of 131,402 significant reads to major bacterial taxa revealed five main bacterial phyla dominating the sampled sites: Proteobacteria (68%), Firmicutes (13%), Fusobacteria (12%), Bacteriodetes (6%), and Spirochetes (0.03%). Further analysis revealed distinct bacterial consortia that primarily included (1) marine Vibrio spp.--suggesting a "marine Vibrio phenomenon"; (2) potential human pathogens; and (3) oil-degrading bacteria. We discuss two divergent microbial consortia that were sampled from Solar Lake West near Taba/Eilat and Saline Lake in Ras Muhammad; these consortia contained the highest abundance of human pathogens and no pathogens, respectively. Our results draw attention to the effects of industrialization on the Red Sea and suggest the need for further analysis to overcome the hazardous effects observed at the impacted sites. [ABSTRACT FROM AUTHOR]

Calcium hexaluminate (CA6) was incorporated into the matrix of magnesio aluminate spinel-alumina (MA-A) via infiltration of a porous preform fabricated from α-Al2O3 and MgO powders with a saturated calcium acetate solution and subsequent firing, forming CA6/(MA-A) functionally composites with graded fracture toughness. Actually, the porous preform was partially and perpendicularly immersed (1/4 of its length) in the solution. Owing to the capillary action, the calcium acetate solution was absorbed into the porous preform, and the different absorption distance led to the graded solution concentration in the height direction of the porous preform. The in-situ formation of CA6 conferred graded microstructures, as well as improved mechanical properties on the resultant composites. The CA6 content decreased gradually along the solution absorption direction, i.e., from one end [CA6/(MA-A) region] immersed in solution to the other end [MA-A region], reducing evidently the formation of layered structure along the direction, while increasing gradually the formation of spherical alumina particles. The CA6/(MA-A) region had a better toughness that could prevent the crack propagation and improve the spalling resistance. Meanwhile, the MA-A region could provide structural support, because of the higher Vickers hardness and density. [ABSTRACT FROM AUTHOR]

Calcium hexaluminate (CA6) was incorporated into the matrix of magnesio aluminate spinel-alumina (MA-A) via infiltration of a porous preform fabricated from a-Al2O3 and MgO powders with a saturated calcium acetate solution and subsequent firing, forming CA6/(MA-A) functionally composites with graded fracture toughness. Actually, the porous preform was partially and perpendicularly immersed (1/4 of its length) in the solution. Owing to the capillary action, the calcium acetate solution was absorbed into the porous preform, and the different absorption distance led to the graded solution concentration in the height direction of the porous preform. The in-situ formation of CA6 conferred graded microstructures, as well as improved mechanical properties on the resultant composites. The CA6 content decreased gradually along the solution absorption direction, i.e., from one end [CA6/(MA-A) region] immersed in solution to the other end [MA-A region], reducing evidently the formation of layered structure along the direction, while increasing gradually the formation of spherical alumina particles. The CA6/(MA-A) region had a better toughness that could prevent the crack propagation and improve the spalling resistance. Meanwhile, the MA-A region could provide structural support, because of the higher Vickers hardness and density. [ABSTRACT FROM AUTHOR]

For solar thermal harvesting, an experimental study was performed on the thermal absorption performance of water-based carbon nanotubes (CNTs), Cu, and Al2O3 nanofluids using a halogen lamp-based thermal radiation system. The effect of nanoparticle concentrations (0.01 wt.%, 0.1 wt.%, and 1 wt.%) on the nanofluid dispersion, stability, and thermal absorption characteristics was investigated, and a comparative analysis was performed for each type of nanofluid. All types of nanofluids increased the absorbance and electrical conductivity with increasing nanoparticle concentration, which contributed to improving the thermal absorption performance of nanofluids. The results showed that the thermal absorption performance was high in the order of carbon-based nanofluids (CNTs), metal-based nanofluids (Cu), and oxide-based nanofluids (Al2O3). In CNTs nanofluids, the thermal absorption performance expressed the time reduction rate, which was 12.8%, 16.3%, and 16.4% at 0.01 wt.%, 0.1 wt.%, and 1 wt.% test cases, respectively. Therefore, the 0.1 wt.%-CNTs nanofluid is more economical and appropriate. However, in Al2O3 nanofluids, the time reduction rate of the 1 wt.% nanofluid was significantly higher than that of the 0.01 wt.% and 0.1 wt.% nanofluids. In Cu nanofluids, unlike CNTs and Al2O3 nanofluids, the time reduction rate constantly increased as the nanoparticle concentration increased. [ABSTRACT FROM AUTHOR]