An Analytical Model to Predict and Minimize the Residual Stress of Laser Cladding Process

Laser Cladding is one of the advanced thermal techniques used to repair or modify the surface properties of high value components such as tools, military and aerospace parts. Tensile residual stresses are formed in the thermally treated area of this process. This work focuses on to find out key factors of formation and minimization of tensile residual stresses in dissimilar materials. In order to predict the tensile residual stress, one dimensional analytical model has been adopted. Four cladding materials (Al2O3, TiC, TiO2, ZrO2) on the H13 tool steel substrate and a range of preheating temperature of the substrate, from 300K to 1200K, have been investigated. The thermal strain and Young’s modulus are found as key factors of formation and minimization of residual stresses. Additionally, the investigation of preheating temperature of the substrate showed the reduction of residual stress with increasing the preheating temperature of the substrate

Size-dependent stability of ultra-small α-/β-phase tin nanocrystals synthesized by microplasma

Key features of tin, including electronic band structure and opto-electronic properties, are influenced by the crystal structure. Here the authors report a microplasma process for the synthesis of ultra-small tin nanocrystals in which the crystal structure is dependent on crystallite size

Association of esterase isozymes with morphology in F2 progenies of two growth variants in Poa annua L

International audienc

Sugar composition of apple cultivars and its relationship to sensory evaluation

The increasing consumption of sugars is one of the factors contributing to the obesity epidemic. Our research was carried out on the sugar composition of apples. The purpose of the study was to determine the quantitative and qualitative composition of sugars of different apple varieties from the East Bohemia region. In this study dry matter content and sensory characteristics were also evaluated. Apples contain fructose, glucose and sucrose. Fructose is known to be a highly lipogenic sugar that has profound metabolic effects in the liver, and has been associated with many of the components of the metabolic syndrome (insulin resistance, elevated waist circumference, dyslipidemia, and hypertension). Fructose, glucose and sucrose in different apple cultivars were extracted with ethanol, derivatized, and determined by gas chromatography. 17 cultivars of apple were analysed. The average fructose content was 6.52 ± 1 g/100 g of apple (8.1 – ‘Golden Delicious’, 4.8 – ‘Selena’), glucose content 1.46 ± 0.55 g/100 g of apple (3 – ‘Red Delicious’, 0.9 – ‘Ontario’), and sucrose content 4.75 ± 1.35 g/100 g of apple (7.2 – ‘Opal’, 2.1 – ‘Melrose’). The cultivars suitable for nutrition of patients with metabolic syndrome are ‘Selena’ and ‘Ontario’.Zwiększenie spożycia cukrów jest jednym z czynników mających wpływ na epidemię otyłości. Prezentowane wyniki badań dotyczą składu cukrów w jabłkach. Celem badań był wybór odmian jabłek odpowiednich pod względem zdrowego odżywiania, tj. ilościowego i jakościowego składu cukrów. Jabłka zawierają fruktozę, glukozę i sacharozę. Dla przykładu fruktoza jest cukrem wysoce lipogennym, który ma istotny wpływ na metabolizm w wątrobie i wiąże się z wieloma czynnikami zespołu metabolicznego (oporność na insulinę, otyłość brzuszna, dyslipidemia i nadciśnienie). Fruktoza, glukoza i sacharoza z jabłek różnych odmian zostały wyekstrahowane etanolem, derywatyzowane i oznaczane metodą chromatografii gazowej. Analizie poddano 17 odmian jabłek. Zawartość fruktozy kształtowała się na poziomie 6,52 ± 1 g/100 g jabłek (8,1 – ‘Golden Delicious’, 4,8 – ‘Selena’). Zawartość glukozy wynosiła 1,46 ± 0,55 g/100 g jabłek (3,0 – ‘Red Delicious’, 0,9 – ‘Ontario’), a sacharozy – 4,75 ± 1,35 g/100 g jabłek (7,2 – ‘Opal’, 2,1 – ‘Melrose’). Odmiany jabłek ‘Selena’ i ‘Ontario’ okazały się jako najbardziej odpowiednie do stosowania w żywieniu pacjentów z zespołem metabolicznym

Coping with employment uncertainty: A comparison of employed and unemployed workers

This study examined coping with stress associated with employment uncertainty for comparable samples of laid-off and employed high-technology workers. It was expected that different coping strategies would be associated with perceived stress for employed vs. unemployed people. Although unemployed participants reported higher levels of stress compared with employed participants, employment uncertainty mediated the association between employment status and perceived stress. Emotio