Neutron Cross Section and Emission Spectra Calculations of Na Nucleus

Flibe (Li₂BeF₄) and Flinabe (LiFNaFBeF₂) are molten salt which are used as a first wall and blanket in advanced power extraction. Since they have low vapor pressure at high temperature and don’t pollute plasma. Moreover, they are used as a coolant material due to their high thermal cycling capacity. There are lots of benefits of using liquid wall such as reducing cost, increasing the reactor power and extending the life time of first steel wall. Being in Flinabe (LiFNaFBeF₂) molten salt, ²³ Na is also considered as a coolant material in fast reactors. Therefore, the reaction including neutron and ²³ Na is getting important. In this study, the cross section calculations of neutron induced reactions for ²³ Na were performed. Using pre-equilibrium and equilibrium models, excitation functions of ²³ Na(n,p)²³ Ne, ²³ Na(n,d)²² Ne, ²³ Na(n,α)²⁰ F, ²³ Na(n,2n)²² Na reactions and ²³ Na(n,xα), ²³ Na(n,xn) emission spectrums were calculated. We calculated alpha emission spectrum obtained when ²³ Na nuclei projectiled with 14.1 MeV neutrons and also neutron emission spectrum emitted when ²³ Na nuclei was bombardment with 14.6 MeV neutrons.     

Thermosonication of peach juice: investigation of PPO and POD activities,physicochemical and bioactive compounds changes,and development of FT-IR–based chemometric models for the evaluation of quality

In this research, the effect of thermosonication on peach juice was investigated. Enzyme inactivation increased with increasing power, temperature, and time. Enzymes were completely inactivated by thermosonication at 60 °C that was lower than the complete inactivation temperature (70 °C) of thermal treatment. Generally, as pH decreased, titratable acidity and °Brix increased by increasing temperature for each thermosonication treatment. The color of peach juice was preserved, and it became lighter. The bioactive components were protected with thermosonication. Fourier transform infrared (FT-IR) spectroscopy with chemometrics was used to evaluate polyphenol oxidase and peroxidase activity and quality attributes during thermosonication treatment. Moreover, the treatment methods were differentiated using principal component analysis, and models that correlated enzyme activity, quality attributes, and bioactive compounds with infrared spectra were constructed using partial least-squares. FT-IR with chemometrics can be used as a reliable method in peach juice quality determination during thermosonication.     

Determination of optimum welding parameters in connecting high alloyed X53CrMnNiN219 and X45CrSi93 steels by friction welding

In this study, different welding parameters were applied to two different steels with high alloys and mechanical and metallographical investigations are performed. Thus, the optimum welding parameters were determined for these materials and working conditions. 12·30 diameter steel bars made up of 1·4871 (X53CrMnNiN219) and 1·4718 (X45CrSi93) steel were used as experimental material. The material loss increased with increase in friction and rotating pressure. No fracture at the welding region was observed and the highest fracture energy was identified in B5 group. Based on micro hardness investigation; the hardness profile reached its minimum value at the welding region.     

On the permeability of columnar dendritic networks in solidifying metals

Equations in the literature developed to estimate the permeability of columnar dendritic networks have been evaluated by using datasets from solidifying metals with data at low solid fractions. Analysis has shown that these equations provide generally poor fits to the experimental data regardless of the direction of the flow of liquid. New semi-empirical equations that provide much better fits to data in the entire range of solid fractions have been introduced in this study.     

Surface Characterization and Corrosion Resistance of Boron Nitride Coated Titanium Dental Implants

Protection of Metals and Physical Chemistry of Surfaces - Surface modifications of dental implants are of vital importance to enhance osseointegration and improve their corrosion resistance. This...     

Morphologic characterization and fractal analysis of lapped and polished surfaces of quartz single crystals

Lapping and polishing are industrial processes sometimes used alternatively for surface finishing of hard and brittle materials. This article presents advanced image analysis of surfaces of quartz crystal blanks finished by lapping and polishing. Scanning electron micrographs were obtained from workpiece surfaces parallel to Y-, AT-, and Z-cut crystal planes treated with different normal stress and abrasive grit size, and stereometric and fractal/multifractal approaches were used to analyze the respective surfaces. Fractal dimensions and segmentation parameters were able to decode the effect of normal stress increasing on the surface roughness of lapped and polished samples. Moreover, the texture isotropy and the bifractal—hence agglomerated—nature of the surface patterns, suggest that both treatments dismiss the anisotropic signature of hardness and fracture toughness inherent to each crystal plane. This study provides promising results regarding the applicability of fractal analysis in the assessment of surfaces severely worn by the combined effect of brittle microcracking and plastic deformation mechanisms.     

Subcooled Flow Boiling Over Microstructured Plates In Rectangular Minichannels

Microstructures offer enhancements in boiling heat transfer by increasing bubble departure frequency, active nucleation site density, critical cavity size, and surface area. Integration of microstructures to surfaces alters significant surface parameters such as porosity of the microstructured plates, contact angle, and configuration of microstructures on the surface, which all affect boiling heat transfer. The goal of this study is to investigate boiling heat transfer on different microstructured plates and the effect of various microscale surface morphologies on boiling heat transfer. The microstructured surfaces were formed on aluminum alloy 2024 sheets with the use of a simple and environmentally friendly technique of random mechanical sanding (grits of #36, #60, #400, and #1,000). Distilled water was pumped using a micro gear pump to the rectangular minichannel test section at flow rates of 100, 180, and 290 ml/min, which correspond to mass fluxes of 5.46, 10.58, and 16.15 kg/m².s, respectively. It was observed that surfaces with low grit (grit #36) showed no considerable enhancement, whereas the use of higher grit counts considerably enhanced boiling heat transfer up to a critical grit count. The results were supported by the images from the performed visualization of flow boiling.     

Knowledge extraction for water gas shift reaction over noble metal catalysts from publications in the literature between 2002 and 2012

In this work, a database (containing 4360 experimental data points) on water gas shift reaction (WGS) over Pt and Au based catalysts was constructed using the data obtained from the published papers between the years 2002 and 2012. Then, the database was analyzed using three data mining tools to extract knowledge in three areas: Decision trees to determine the empirical rules and conditions that lead to high catalytic performance (high CO conversion); artificial neural networks (ANNs) to determine the relative importance of various catalyst preparation and operational variables and their effects on CO conversion; support vector machines (SVMs) to predict the outcome of unstudied experimental conditions. It was concluded that, all three models were quite successful and they complement each other to extract knowledge from the past published works and to deduce useful trends, rules and correlations, which are not easily comprehensible by the naked eyes.     

Calculation of a phase diagram for the ice II - V - VI transitions

In this study we calculate the P - T phase diagram of ice II - V - VI using a mean field model. Our calculated phase line equations are fitted to the experimental data from the literature. There is a very good agreement between our calculated and experimentally observed P - T phase diagram of ice II - V - VI.