Investigation of tungsten heavy alloys using powder metallurgy technique

Recently, developing new alloys of Tungsten heavy (WHA) is the most important issue that researchers considered due to their wide applications of radiation protectors, vibration absorber, kinetic energy penetrators and heavy-duty electrical contacts. The present work shows 9 different Tungsten alloys with a variety of weight percent’s from "Graphene" as a Nano- particle additive. The proposed alloys produced by minimizing manufacturing parameters by applying the Taguchi technique. In addition, this work used to relate the Powder-Metallurgy (PM) parameters such as Sintering Temperature (ST) level, the weight % of the added Nano-particle of Graphene (Gw) and the type of Process Control Agent (PCA) with the mechanical characteristics such as Young’s modulus, modulus of Bulk, modulus of Shear, Poisson's number, Vickers hardness, Grain size , Relative Density. The results showed that specimen number 8 is given higher values of modulus of elasticity, reached 326.2 GPa, bulk value of 255.64 GPa, and shear value of 126.7 GPa with PM preparation condition at 15000C sintering temperature, stearic acid as a process control agent (PCA) and 0.0 %Wt. of Graphene.

Evaluation of various preparation methods of oil palm fiber (OPF) biochar for ammonia-nitrogen (NH3-N) removal

The aim of this study is to develop a oil palm based biochar for the selective removal of NH3-N in low concentration from aquaculture wastewater. In this study, three different preparation methods of biochar were evaluated for the adsorption of NH3-N from synthetic aquaculture wastewater. The three methods are pyrolysis, activation with acid before pyrolysis and activation after pyrolysis with numerous oxidizing agents. In the 1st method, various biochars have been prepared at different pyrolysis temperatures (300 – 500 °C) and holding time (0.5 – 2 hr). The maximum removal efficiency of 50 % was achieved at preparation condition of 300 °C and 2 hr. In the 2nd method, the acid activated raw OPF was pyrolyze at 300 °C, 1 hr. The maximum removal was lower compared to the 1st method without acid treatment. In the 3rd Method, the optimized biochar from the 1st method was activated with different activating agents such as, HNO3, HCl, H3PO4, H2SO4, CH3COOH and H2O2 at 100 °C for 2 hr. It was noticed that activation after pyrolysis did not show any improvement in the removal of NH3-N from synthetic aquaculture wastewater. Characterization of optimized samples were carried out to investigate the adsorption mechanism process of NH3-N. The 1st method (pyrolysis) was the best which reported the highest (50 %) removal of NH3-N. Pyrolyzed OPF is a potential adsorbent for NH3-N.

Optimized preparation of quassinoids rich Eurycoma longifolia Jack, TAF2-phospholipid complex and its effects on oral bioavailability

Eurycoma longifolia Jack is a plant of the genus Eurycoma in Simaroubaceae. Eurycomanone is one of the main quassinoids of E. longifolia. Unfortunately, these quassinoids exhibit low bioavailability . In the present study, a phospholipid complex (TAF2-PC) was prepared to improve the oral bioavailability of TAF2 (Tongkat Ali Fraction 2). The complexation rate of eurycomanone and phospholipid was used as the index of success in the phospholipid complexes. The effects of reaction solvent, reaction temperature, drug concentration, drug-lipid ratio and reaction time on thecomplexation rate were investigated. Response Surface-Box-Behnken Design Method was performed to optimize the preparation technology and the pharmacokinetics of phospholipid complex of TAF2 were studied in rats. Our results showed that the optimum preparation condition of TAF2-phospholipid complex were as follows: reaction solvent, anhydrous ethanol; reaction time, 1 h; the ratio of TAF2 to phospholipid, 2.28; reaction temperature, 40.85 ℃; TAF2 concentration, 32.66 mg/ml; and complexation rate, 95.04 ± 0.4% (n=3).The results of pharmacokinetic study showed that the relative bioavailability was increased to 209.20% in the TAF2-phospholipid complex-treated rats.Thus,this phospholipid-complex-technique shows potential for enhancing oral bioavailability of poorly absorbed quassinoid-rich E. longifolia extract, TAF2.

The Physicochemical Characteristic of Activated Carbon Based on Sludge and Preparation Method

To understand the features and best preparation of sludge activated carbon (SAC), and the pore structure, component, adsorption characteristics, and the yield rate of SAC, many tests have been carried out. The study illustrated that the pore structure was mostly mesopore and amorphous pore such as the ink bottle hole. In terms of different preparations to obtain SAC, the yield of SAC in sample No.1 achieved 88.09%. Using the preparation of ZnCl2 as an activator, the iodine adsorption value was significantly higher than other preparations. However, the content of quartz in sample No.1 achieved a maximum of 52.51%. Charcoal was detected in all samples except sample nos 9-12. The adsorption capacity of Cu(II) and Cd(II) reached a maximum of 600.02 mg.kg-1 and 383.2 mg.kg-1. The results showed an optimum preparation condition, which was by using the ZnCl2 as an activator, 2:1 as the impregnated ratio, 40% concentration in activator and at 400ºC reaction temperature could create rich pore structure and charcoal inside.

Applications of the Water-Dispersible L-Cysteine-Capped ZnS:Mn Nanocrystals as a Selective Photosensor and an Efficient Photocatalyst

In this study, the ZnS:Mn nanocrystals (NCs) were prepared by capping the NC surface with a conventional amino acid, L-cysteine (Cys) molecules, at an acidic (pH 5) aqueous solution. The optical and physical characterizations of the ZnS:Mn-Cys-pH5 NCs were performed using various spectroscopic methods. For instance, the UV-visible and PL spectra of the ZnS:Mn-Cys-pH5 NCs showed broad peaks at 296 and 586 nm, respectively. The obtained HR-TEM image of the ZnS:Mn- Cys-pH5 NCs product showed spherical particle images with an average size of 6.15 nm in the solid state. In addition, measured surface charge of the colloidal ZnS:Mn-Cys-pH5 NCs using a zeta-PSA spectroscopy was −57.9 mV even at the acidic preparation condition. Therefore, the ZnS:Mn-Cys-pH5 NCs were applied as a photosensor to detect specific transition metal cations. As a result, the ZnS:Mn-Cys-pH5 NCs showed exclusive luminescence quenching effect for Fe(II) ions, which suggested that the ZnS:Mn-Cys-pH5 NCs can be applied as a photo-chemical sensor for Fe2+ ion detection in a practical water sample. The sensing ion selectivity of the ZnS:Mn-Cys-pH5 NCs was completely different comparing to ZnS:Mn NCs surface capped with other amino acids at the same condition. In addition, the catalytic activity of the ZnS:Mn-Cys-pH5 NCs was studied in the degradation reaction of an organic dye (methylene blue) molecule under UV light irradiation.

Thermal Preparation and Application of a Novel Silicon Fertilizer Using Talc and Calcium Carbonate as Starting Materials

The deficiency of available silicon (Si) incurred by year-round agricultural and horticultural practices highlights the significance of Si fertilization for soil replenishment. This study focuses on a novel and economical route for the synthesis of Si fertilizer via the calcination method using talc and calcium carbonate (CaCO3) as starting materials. The molar ratio of talc to CaCO3 of 1:2.0, calcination temperature of 1150 °C and calcination time of 120 min were identified as the optimal conditions to maximize the available Si content of the prepared Si fertilizer. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) characterizations elucidate the principles of the calcination temperature-dependent microstructure evolution of Si fertilizers, and the akermanite Ca2Mg(Si2O7) and merwinite Ca3Mg(SiO4)2 were identified as the primary silicates products. The results of release and solubility experiments suggest the content of available metallic element and slow-release property of the Si fertilizer obtained at the optimum preparation condition (Si-OPC). The surface morphology and properties of Si-OPC were illuminated by the results of scanning electron microscope (SEM), surface area and nitrogen adsorption analysis. The acceleration action of CaCO3 in the decomposition process of talc was demonstrated by the thermogravimetry-differential scanning calorimetry (TG-DSC) test. The pot experiment corroborates that 5 g kg−1 soil Si-OPC application sufficed to facilitate the pakchoi growth by providing nutrient elements. This evidence indicates the prepared Si fertilizer as a promising candidate for Si-deficient soil replenishment.

The Preparation, Antioxidant Activity Evaluation, and Iron-Deficient Anemic Improvement of Oat (Avena sativa L.) Peptides–Ferrous Chelate

Iron-chelating peptides have been widely considered as one of the best iron supplements to alleviate the iron deficiency. In this study, a novel oat peptides–ferrous (OP-Fe2+) chelate was prepared from antioxidant oat peptides obtained in the laboratory of the authors. The optimal preparation condition was obtained through the single-factor and response surface methodology, and the chelating rate could reach up to 62.6%. After chelation, the OP-Fe2+ chelate exhibited a significantly higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity than oat peptides. It was discovered that the hemoglobin concentration and the number of red blood cell levels in OP-Fe2+-treated iron-deficient anemic (IDA) rats were significantly higher than untreated IDA rats. The OP-Fe2+ chelate could also improve the hypertrophy of the spleen, serum iron (SI), total iron and binding capacity, and serum ferritin levels in the IDA rats. In addition, the OP-Fe2+ treatment significantly increased the antioxidant activities of super oxidase and glutathione in the liver homogenate of the IDA rats. Therefore, the OP-Fe2+ chelate is an effective type of iron supplement for IDA rats, which could be a promising source with anti-anemia and antioxidant activity.

Investigation on the La Replacement and Little Additive Modification of High-Performance Permanent Magnetic Strontium-Ferrite

In this work, an experiment was carried out to investigate the preparation condition of anisotropic, Fe-deficient, M-type Sr ferrite with optimum magnetic and physical properties by changing experimental parameters, such as the La substitution amount and little additive modification during fine milling process. The compositions of the calcined ferrites were chosen according to the stoichiometry LaxSr1-xFe12-2xO19, where M-type single-phase calcined powder was synthesized with a composition of x = 0.30. The effect of CaCO3, SiO2, and Co3O4 inter-additives on the Sr ferrite was also discussed in order to obtain low-temperature sintered magnets. The magnetic properties of Br = 4608 Gauss, bHc = 3650 Oe, iHc = 3765 Oe, and (BH)max = 5.23 MGOe were obtained for Sr ferrite hard magnets with low cobalt content at 1.7 wt%, which will eventually be used as high-end permanent magnets for the high-efficiency motor application in automobiles with Br > 4600 ± 50 G and iHc > 3600 ± 50 Oe.

Preparation of Red Phosphor Sr2Si5N8: Eu2+ by Pellet Method and Its Optical Characteristics

Red Sr2Si5N8: Eu2+ phosphor with excellent properties was successfully synthesized by pellet method, an effective synthesis technology presented in this work. The influence of reactive conditions such as pellet pressure, position of samples in carbon powder, and Eu2+ ion concentration on the properties of crystallinity, particle size, and the photoluminescence properties of Sr2Si5N8: Eu2+ phosphor were studied in detail. Our results show that the optimum preparation condition is 1500, 5 MPa pellet pressure, and the middle position in carbon powder. The phosphor has improved its efficiency under excitation of near UV and blue LEDs, and it emits red light at around 620 nm. In addition, red LEDs were successfully prepared by using Sr2Si5N8: Eu2+ phosphor combined with UV-chips with maximum luminous efficiency at 9.443 lm/W, when the molar concentration of Eu2+ ion reached 0.001.