Influence of Bifilm Defects Generated during Mould Filling on the Tensile Properties of Al–Si–Mg Cast Alloys

Entrapped double oxide film defects are known to be the most detrimental defects during the casting of aluminium alloys. In addition, hydrogen dissolved in the aluminium melt was suggested to pass into the defects to expand them and cause hydrogen porosity. In this work, the effect of two important casting parameters (the filtration and hydrogen content) on the properties of Al–7 Si–0.3 Mg alloy castings was studied using a full factorial design of experiments approach. Casting properties such as the Weibull modulus and position parameter of the elongation and the tensile strength were considered as response parameters. The results suggested that adopting 10 PPI filters in the gating system resulted in a considerable boost of the Weibull moduli of the tensile strength and elongation due to the enhanced mould filling conditions that minimised the possibility of oxide film entrainment. In addition, the results showed that reducing the hydrogen content in the castings samples from 0.257 to 0.132 cm3/100 g Al was associated with a noticeable decrease in the size of bifilm defects with a corresponding improvement in the mechanical properties. Such significant effect of the process parameters studied on the casting properties suggests that the more careful and quiescent mould filling practice and the lower the hydrogen level of the casting, the higher the quality and reliability of the castings produced.

Melt Treatment-Porosity Formation Relationship in Al-Si Cast Alloys

The present study focuses on the porosity formation in three Al-Si cast alloys widely used in automotive industries viz. A319.0, A356.0, and A413.0 alloys under various conditions: stirring, degassing. Sr level, amount of grain refining, combined modification and grain refining, as well as hydrogen level. The solidification rate was the same for all alloys in terms of the mold used and its temperature. The microstructural investigations were carried out quantitatively using an optical microscope-image analyzer system scanning systematically over a polished sample area of 25 mm × 25 mm and qualitatively using an electron probe microanalzer equipped with EDS and WDS systems. The results were coupled with hardness measurements.

Hybrid Intelligent Modelling in Renewable Energy Sources-Based Microgrid. A Variable Estimation of the Hydrogen Subsystem Oriented to the Energy Management Strategy

This work deals with the prediction of variables for a hydrogen energy storage system integrated into a microgrid. Due to the fact that this kind of system has a nonlinear behaviour, the use of traditional techniques is not accurate enough to generate good models of the system under study. Then, a hybrid intelligent system, based on clustering and regression techniques, has been developed and implemented to predict the power, the hydrogen level and the hydrogen system degradation. In this research, a hybrid intelligent model was created and validated over a dataset from a lab-size migrogrid. The achieved results show a better performance than other well-known classical regression methods, allowing us to predict the hydrogen consumption/generation with a mean absolute error of 0.63% with the test dataset respect to the maximum power of the system.

Effects of Cooking Processes on Breath Hydrogen and Colonic Fermentation of Soybean

Background: Soybean is rich in dietary fibers; consequently, soybean ingestion considerably increases the breath level of hydrogen molecules via anaerobic colonic fermentation. However, the influence of cooking methods on this effect, which can affect the overall health benefits of soybean, remains unknown. Objectives: The aim is to examine whether different methods of cooking soybean affect the colonic fermentation process. Methods: Nine healthy adult volunteers participated in the study; they ingested either roasted soybean flour (kinako) or well-boiled soybean (BS). Differences in their breath components were compared. Both test meals were cooked using 80 g of soybeans per individual. After a 12 h fast, the participants ate the test meals, and their breath hydrogen level was analyzed every 1 h for 9 h by using a gas chromatograph with a semiconductor detector. In addition, particle size distribution and soluble/ insoluble fibers in the feces were examined. Results: The oro-cecal transit time did not significantly differ between individuals who ingested kinako and BS. However, the area under the curve between 7 and 9 h after the ingestion of BS was significantly increased compared with that after the ingestion of kinako. The nutritional analysis indicated that the content of both soluble and insoluble fibers in BS was higher than that in kinako. In addition, the levels of unfermented fragments and soluble/insoluble fibers in the feces were increased after the ingestion of kinako compared with those after the ingestion of kinako. Conclusion: Cooking methods alter the composition of non-digestible fibers in soybean, and this can result in the lack of fermentative particles in the feces, thereby causing alterations in the breath level of hydrogen via colonic fermentation.

ИССЛЕДОВАНИЕ НИТРИД-ГАЛЛИЕВЫХ МАЛОШУМЯЩИХ УСИЛИТЕЛЕЙ ПРИ КРИОГЕННЫХ ТЕМПЕРАТУРАХ

В статье представлены результаты исследования возможности применения при криогенных температурах водородного уровня дискретных приборов и монолитных схем на основе нитрида галлия в составе малошумящих усилителей сантиметрового и миллиметрового диапазона длин волн для приемных устройств систем дистанционного зондирования Земли из космоса и в составе криогенных комплексов наблюдения космического пространства. The article presents the results of the research on the possibility of using discrete devices and gallium nitride monolithic circuits at the cryogenic temperatures of hydrogen level as part of low-noise amplifiers of centimeter and millimeter-wave bands used in receivers of Earth remote sensing space systems and in cryogenic systems for space observation.

210 Mw Turbo Generator’s Hydrogen Gas Cooling System Online Monitoring and Controlling using Node Red Flow Based IoT

This undertaking is about plan and execution of remote observing and controlling of 210 MW TURBO GENERATOR'S HYDROGEN COOLING SYSTEM utilizing NODE RED BASED IOT PROGRAM. The quicker heat scattering of generators in power plants calls for hydrogen cooling, and water is utilized as coolant to chill off the hot hydrogen which turns out from the hydrogen cooling framework (HCS) at the producing end. Along these lines, in enormous creating plants, the way toward cooling and the coolant become basic pieces of the warmth exchangers. Subsequently, necessity of a dependable HCS is an unquestionable requirement. The primary point of this task is to naturally refill the hydrogen gas in the hydrogen cooling arrangement of turbo generators at whatever point the hydrogen level gets diminished than the ideal hydrogen level. This framework functions admirably in both ordinary necessity conditions and furthermore during basic prerequisite conditions, when there is a surprising spillage in the framework. The whole procedure control and observing, famously known as human–machine interface of HCS, has been created and reproduced on NODE RED BASED IOT PROGRAM. [1],[ 3],[5]