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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 work represents the shaping of alumina–zinc oxide (AZ) samples with the direct coagulation casting method. The effect of zinc oxide (0, 10, 20, 30, and 40 wt%) and the firing temperatures on the phase composition, microstructure, physical properties, and mechanical properties of the AZ samples were studied. The effect of titanium oxide (2, 5, and 7 wt%) and the firing temperatures on the phase composition, microstructure, physical properties, and mechanical properties of the AZ sample with 40 wt% of zinc oxide were studied. Furthermore, the optical properties, magnetic properties, and antimicrobial activity were measured. The results indicate that the increase in zinc oxide enhances the formation of zinc aluminate, which has a gahnite phase. Moreover, increasing the zinc oxide increases the apparent porosity and decreases the grain size and bulk density at various firing temperatures. On the other hand, the addition of 5 wt% titanium oxide increases the bulk density to 3.5 g/cm3 compared to 1.72 g/cm3 with no titania. The apparent porosity and compressive strength reached 5% and 69.2 MPa after 5 wt% TiO2 addition; respectively, compared to 59% and 27.2 MPa with no titania addition. The prepared samples show promising optical band gap of 2.98–3.97 eV, a mixed magnetic behavior, and favorable antibacterial activity against E. coli, S. aureus, B. cereus strains. [ABSTRACT FROM AUTHOR]

The main goal of this work is to study the effects of some transition metal-oxides, i.e. ZnO, TiO2, and Fe2O3, on inhibition of spinel formation during cordierite fabrication from granite waste, talc, and alumina by direct coagulation casting method. Moreover, the effect of these oxides on sinterability, microstructure, hardness and electrical properties was achieved. The casted specimens were sintered at different temperatures then examined by X-ray diffraction technique to follow the formed phases. The physical properties were determined according to Archimedes rule. The microstructure was also investigated by scanning electron microscope, while the hardness was determined by Vicker's method. The electrical properties were evaluated by an impedance analyzer. The results indicated that sintered cordierite-spinel ceramics were successfully prepared with inhibition of spinel formation after addition of some transition metals and sintering up to 1250 °C. ZnO promoted the formation of spinel while TiO2 and Fe2O3 inhibited the formation of spinel and promoted the formation of cordierite. The ZnO-containing cordierites exhibited their best properties after sintering at 1200 °C, while the samples containing TiO2 and Fe2O3 showed their best properties after sintering at 1250 °C. The physical, mechanical and electrical properties were improved after increasing the amount of added metal oxides. The dielectric constant values were higher for the samples that contain TiO2 than those contain Fe2O3 and ZnO. Moreover, the hardness of all samples was in a narrow range of 6.14–6.61 GPa. [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]

The aim of this work is to synthesize the seeds of CoxMg1-xAl2O4 nano-spinel particles for pigment fabrication using a microwave-assisted method. Also, we report on a novel, less toxic, flexible, and reproducible microwave- assisted method for starch-based synthesis of spinels. Furthermore, substantial efforts were devoted to obtaining a nanopowder while reducing total synthesis time from many hours to a few minutes. The obtained powders were characterized by XRD, FT-1R, TEM, and EDSA techniques. The results show that CoxMg1-xAl2O4 spinel is in an amorphous form after microwave treatment at 1000 W with particle sizes of less than 20 nm and that spinel first began to crystallize at a temperature of 550 °C. [ABSTRACT FROM AUTHOR]

The sinterability of gelcast Fe2O3-doped and MgO-doped alumina ceramics containing 55 vol.-% solid loading was studied at different temperatures and compared with gelcasted sintered pure alumina. Physical properties (bulk density and apparent porosity), phase composition, microstructure and mechanical properties (microhardness and toughness) of the sintered bodies were investigated. The results revealed that the sintered doped bodies exhibited dense and compact microstructure as compared with pure alumina bodies. The hardness of Fe2O3-doped bodies showed the lowest values among the others due to the lower elastic modulus of the secondary phases formed and due to the enhanced grain growth after addition of a higher amount of Fe2O3. On the contrary, the addition of a small amount of MgO reduced the grain growth which enhanced hardness. Fracture toughness results showed a great increase in Fe2O3 doped ceramics due to the presence of large grains, while in MgO-doped ceramics, the facture toughness increase was related to a residual decrease in porosity. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Chinese Society of Rare Earths is the property of Editorial Department of Journal of the Chinese Society of Rare Earths and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Low thermal expansion ceramics are defined as ceramic materials with a thermal expansion coefficient below 2.0x10-6 °C-1. Compared to other conventional ceramics, these materials exhibit exceptional resistance to high temperatures and thermal shock, maintaining stability in complex environments characterized by high temperatures and abrupt temperature changes. They find widespread application in various fields, including refractory materials, catalyst carriers, electronic devices, and aerospace. This article reviews the classification, preparation methods, and application domains of low thermal expansion ceramics, and examines the research advancements of several common types such as cordierite, aluminum titanate, NaZr2(PO4)3, and lithium ceramics. Additionally, the article discusses the development trends in this field. [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]

Copyright of Journal of King Abdulaziz University: Marine Sciences is the property of King Abdulaziz University, Scientific Publishing Centre and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To investigate the efficiency of gemini surfactant based organoclays (OMts) for the stabilization of O/W emulsions, different ammonium gemini surfactants with semi-rigid hydrophobic chains and spacer lengths were used for the modification of sodium montmorillionite (Mt). The composition and morphology of the resulting organoclays were characterized by Fourier transform infraredspectroscopy, X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy and thermogravimetric analysis. The results showed that these surfactants are more efficient than conventional surfactants and hydrocarbon type gemini surfactant analogous in the modification of Mt. An important increase of the d-spacing values was obtained particularly for long hydrocarbon chains and spacers. The OMt's thermal properties and hydrophobicity were also governed by the structure of surfactants. The stabilizing behavior of gemini surfactants, OMt as well as surfactant/OMt mixtures in oil/water (1:1, v/v) emulsions was investigated by macroscopic and microscopic morphological observations. Better stabilization was achieved by G(10-4-10) surfactant bearing decyl chains and OMts with high surfactant concentration. [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]

The present research investigates the sol–gel route using Pechini, citrate and alkoxide methods in order to obtain strontium doped lanthanum manganite perovskite La0.5Sr0.5MnO3 (LSMO) as nanometric materials. The electrocatalytic activity of carbon supported perovskite denoted (LSMO/C) used as an electrocatalyst for oxygen reduction reaction (ORR) in 0.1 M KOH electrolyte has been studied using a rotating disk electrode. The oxide powders were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Brunauer–Emmett–Teller (BET) method and transmission electron microscopy (TEM). X-ray diffraction results showed that the powders were primarily identified to a perovskite structure phase La0.5Sr0.5MnO3 with nanometric sized particles of about 20 nm and homogeneous morphology. Results related to the electrochemical study of ORR showed that the perovskite oxide synthesized by the Pechini method yielded an electrode material with improved electrochemical activity compared to those elaborated through citrate and alkoxide methods. [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]