Papers by Keyword: Radiation

Abstract: Combination of high energy radiation and chemical vapour deposition in the grafting process for the synthesis of metal adsorbent was investigated. Radiation-induced grafting of glycidyl methacrylate onto kenaf fiber was performed in vapour phase to develop adsorbent for removal of aluminum from aqueous solution. Morphological changes of cross-section kenaf fiber was observed via scanning electron microscope and the thickness of co-monomer in the final graft co-polymer was determined. The comparison in cross-section morphology between ungrafted kenaf fibers and grafted kenaf fiber shows approximately 3.88 [μm] thick of additional grafted layer. The functionalization of the grafted fiber using imidazole was calculated grametrically and verified by elemental analysis. Imidazole has proven to be effective on the adsorption of aluminum ion. It was found that the adsorbent could remove more than 99% aluminum with the highest adsorption capacity of 4.93 [mg/g] at pH 4 and 60 minutes reaction time.

Abstract: Generally, only a few especially acrylic monomers have photoabsorption characteristics to allow for effective stereolithography (STL) to take place. Biomaterial product from palm oil, Acrylated Palm Olein (APO), is seen as an ideal alternative to petroleum-based polymers due the diminishing petrochemical supply and abundant of the natural polymer in the market. In this study, APO as a biopolymer is introduced to synthetic polymers Polyethylene Glycol Dimethylacrylate (PEGDMA) and Polyethylene Glycol Diacrylate (PEGDA), separately. All three polymers offer photoabsorption characteristics that enable them to be the resins for ultraviolet (UV) 3D printing. The crosslinking of both copolymers is optimized by comparing two different UV radiation techniques; UV cured machine and UV STL 3D printer. The degree of crosslinking for both APO-co-PEGDMA and APO-co-PEGDA through gel fraction analysis are studied and compared with their prepolymer resins. As predicted, the maximum degree of crosslinking of APO-co-PEGDMA and APO-co-PEGDA samples are achieved from the fabrication of samples by 3D printing and recorded at 67.50% and 59.50% respectively, comparing to the samples cured by UV cure machine, which recorded maximum crosslinking percentage at only 21.31%. Further analysis is done using swelling test to study water absorption capacities of copolymers and results shows that APO-co-PEGDMA able to retain water at maximum of 42.47% and APO-co-PEGDA at 52.02% from the 3D printed samples, and recorded lowest readings at 22.82% and 25.56% respectively. UV cured samples are recorded to have lowest readings at 3.89% for APO-co-PEGDMA, and 4.23% for APO-co-PEGDA. Fourier Transform Infrared (FTIR) Spectroscopy confirmed the successful crosslinked of the copolymers. Analysis of FTIR shows that there are presence of new peaks and shifting of peaks, indicating that APO is crosslinked with PEGDMA backbone as well as PEGDA backbone. These also suggest that both polymers are suitable to be incorporated with APO as new photopolymer resins, fabricated using UV radiation crosslinking, with PEGDMA shown a slightly better result. All results are agreeable with FTIR results.

Abstract: The influence of Casson nanofluid's participating parameters over a stretched sheet is explored numerically. The fluid momentum equations are transformed to ODEs with suitable dimensional less parameters. Runge-Kutta method of fourth order method is applied. The impact on fields of velocity, temperature and concentration of magnetic, Casson porosity, radiation, Prandtl, Brownian and thermophoresis parameters and chemical reaction parameters are graphically illustrated and discussed qualitatively.

Abstract: The prospects for beneficial application of integrated circuit (IC) capabilities in ambient environments above 450 °C have been significantly improved by recent long-term demonstrations of SiC chips and packaging by NASA Glenn Research Center. This invited paper reviews and updates development of durable SiC IC technology aspects relevant to engineering infusion into beneficial applications, including the first long-duration low-mass Venus lander missions

Abstract: The integral-differential equation of the cascade process for ions was solved using the Laplace transform and the method of successive approximations, taking into account the energy loss during the formation of primary-knocked-on atoms (PKA) in a one-dimensional model of an elementary atom. It is shown that the solution includes a cascade-probability function (CPF) for these particles. The main properties of CPF are considered and its graphical dependencies on the depth of registration are presented. It is shown that with the specific ionization loss coefficient k = 0, the FQM turns into the simplest cascade-probability function. When λ₀→ 0, λ₀→∞ and n→∞, the KV-function is equal to 0. The sum of the probabilities for all possible collisions from 0 to ∞ is 1. As the detection depth h increases, for all values of n, the CRF increases, reaches a maximum and then decreases . With increasing n, the curves shift to the right.

Abstract: Single pellet heating was considered at natural gas combustion product movement with oxidant flow coefficient of α=1.0 with air and oxygen in unconstrained volume. Physical parameters (density, dynamic and kinematic viscosity) and heat transfer properties (temperature, heat capacity, thermal conductivity, thermal diffusivity) of combustion products correspond to the average composition of gas delivered to the Ural region. Iron-ore pellet average properties were evaluated, based on major pellet plant data. Convection and radiant heat transfer coefficients were determined at pellet heating in natural gas combustion products in a mixture with air and oxygen. It was noted that, at switching to gas burning with oxygen radiant heat transfer to the pellet surface increases significantly, as compared to the convection one.

Abstract: Radiation leaving the solid surface provides an important reference for detection in both military and civilian areas. In this paper, total radiation leaving a solid plate is calculated with different emissivities considering the environment radiation. The results prove that a lower emissivity of the surface material has a stronger reflection of irradiance from the Sun, and therefore may enhance the total radiation leaving the plate. This is different from most cases where a lower emissivity always leads to a smaller radiation effects. The emissivity of material coated to the solid surface should be properly chosen according to the detailed surrounding environment as well as the radiative properties of the solid parts in order to achieve a minimum radiation effects.

Abstract: Currently, the world has a lot of research and practical application of intelligent building systems integrated with intelligent power systems. Because Vietnam is a country with potential for solar energy, the integrator of solar energy is being strongly developed. However, the research result of the optimization of electrical energy used by the intelligent type solar integration is rare. This paper presents the design and structure of the module of intelligent control and monitoring via wireless network integrated with the automatic solar concentration system. The system allows easy connection and operation of all electrical power sources including the dispersal solar power to ensure the efficient and lower power consumption. In addition, the solar cell system is applied the Maximum Power Point Tracking technique (MPPT), which helps to stabilize and improve the power generation efficiency of the PV panels. The test results on the module showed absorption performance of automatic solar-cell flat plate systems is raised by 20-30% and power consumption in small households reduced approximately 30%.

Abstract: The most difficult problem of the modern high-tech world is the protection of a living organism from the effects of radiation in the existence of nuclear technology in all areas of daily life. The article considers the problem of finding new effective building materials to protect people and the environment from the threat of the neutron and γ-radiation. Modern radiation-protective materials must have high strength and environmental characteristics of the performances and have a low cost. The authors carried out experimental studies on the development of a new radiation-shielding concrete using natural dunite aggregates from the Urals region. The research included selecting the original components of rational composition and technological characteristics of the concrete mixtures. The results showed its effectiveness compared to traditional granite aggregate used in concrete. On the experimental base of Ural Federal University named after. B.N. Yeltsin the research has shown an increase in efficiency of 1.35-3.0 times the effectiveness of the newly developed protection of electromagnetic radiation to protect against non-ionic and γ-excretions, depending on the energy field.

Abstract: No radiation protection agents have been found to date which would not have toxic side effects while having radioprotective action of unlimited duration. Based on the screening of organo-element chemical compounds, a novel radioprotector sulfotozifan was selected to prevent the acute radiation syndrome in animals. Sulfotozifan belongs to compounds of hazard class 3 (National Standard of the Russian Federation (GOST) 12.1:007.76). A single subcutaneous administration of sulfotozifan at a dose of 38.0 mg / kg of body weight 2-4 days prior to the radiation exposure of animals to an absolute lethal dose, protects 80-100% of the animals from the radiation death. The pretreatment of animals with sulfotozifan 2-4 days prior to the irradiation has a positive effect on the animals’ clinical condition, normalizes their hematological parameters, increases the levels of T and B lymphocytes, inhibits peroxidation of lipids (POL), reduces the concentration of malondialdehyde (MDA), the final product of POL, in the erythrocyte hemolysate and blood plasma, and also promotes a reduction in the formation of radiotoxins. By its organoleptic, physicochemical, and bacterioscopic characteristics, the meat from irradiated animals pretreated with sulfotozifan does not differ significantly from those of the meat from the control animals and thus meets GOST requirements.