Jan Długosz University

About: Jan Długosz University is a education organization based out in Częstochowa, Poland. It is known for research contribution in the topics: Crystal structure & Luminescence. The organization has 749 authors who have published 2311 publications receiving 19395 citations. The organization is also known as: Higher Teacher Education School.

Vibrational and structural properties of unmodified and radiation-modified chalcogenide glasses for advanced optical applications

Abstract: Vibrational and structu ral properties of Ge x Sb 40  x S 60 (x = 25, 27, 35) chalcogeide glasse s are studied in unmodified and J-radiation-modified states by using infr ared spectroscopy, high-energy synchrotr on x-ray diffraction and extended x-ray absorption fine structure spectroscopy. An agreement between radiation-induced structural changes and vibrational properties measured is established. It is suggested that the atomic pairs with wrong coordination created in the framework of coordination topological def ect formation concept play a key role in the formation of radiation-modified state of the investigated glasses. Advantages and disadvantages of post-technological radiation-modification of chalcogenide glasses are considered within configuration co ordinate model for description of unmodified and radiation-modified states. Keywords: Chalcogenide glasses, infrared spectroscopy, high-energy synchrotron x-ray diffraction, extended x-ray absorption fine structure spect roscopy, radiation modification

Modeling of thermal cycle ci engine with multi-stage fuel injection

Abstract: This work presents a complete thermal cycle modeling of a four-stroke diesel engine with a three-dimensional simulation program CFD AVL Fire. The object of the simulation was the S320 Andoria engine. The purpose of the study was to determine the effect of fuel dose distribution on selected parameters of the combustion process. As a result of the modeling, time spatial pressure distributions, rate of pressure increase, heat release rate and NO and soot emission were obtained for 3 injection strategies: no division, one pilot dose and one main dose and two pilot doses and one main dose. It has been found that the use of pilot doses on the one hand reduces engine hardness and lowers NO emissions and on the other hand, increases soot emissions.

Numerical simulations of fluidization dynamics in a hot model of a CLC process

Abstract: Chemical Looping Combustion (CLC) is one of the most promising alternatives for solid fuel combustion. CO 2 concentration in the exhaust gas is high in CLC technology which enables high efficiency of CO 2 capture from flue gas. The use of solid oxygen carriers is a characteristic feature of a CLC process. Oxygen carriers are mainly metal oxides which are characterized by high oxygen transfer capacity and high mechanical resistance.Since the CLC technology is not sufficiently recognized due to its complexity the development of models with real conditions of the CLC equipment is of practical significance.The paper presents numerical simulations of the dynamic fluidized bed for Chemical Looping Combustion using CeSFaMB software. The model was validated on the basis of the results obtained from experiments, which were carried out on the Fluidized-Bed Chemical-Looping-Combustion of Solid-Fuels (FB-CLC-SF) unit. The studies were conducted in air atmosphere at temperature of 850°C. The validation of the 1.5D model showed that the maximum relative error between experiment and simulations results does not exceed 12%.

Fibroblast growth factor-21 and omentin-1 hepatic mRNA expression and serum levels in morbidly obese women with non-alcoholic fatty liver disease.

Abstract: Fibroblast growth factor-21 (FGF21) and omentin-1 have been recognized as potent antidiabetic agents with potential hepatoprotective activity. The aim of this study was to evaluate hepatic FGF21 and omentin-1 mRNA expression as well as their serum levels as predictive markers of liver injury and insulin resistance in morbidly obese women with non-alcoholic fatty liver disease (NAFLD). This study included 56 severely obese women who underwent intraoperative wedge liver biopsy during the bariatric surgery. Hepatic FGF21 and omentin-1 mRNA were assessed by quantitative real-time PCR, while their serum concentrations were measured with commercially available enzyme-linked immunosorbent assays. The FGF21 serum level was significantly higher in patients with a greater extent of steatosis (grade 2 and 3) compared to those without or with mild steatosis (grade 0 and 1) (P = 0.049). Receiver Operating Characteristic analysis, however, showed poor discriminant power for the FGF21 serum levels in differentiating between more and less extensive steatosis with an AUC = 0.666. There was a tendency towards higher levels of hepatic FGF21 mRNA in patients with lobular inflammation and fibrosis and towards lower levels in the case of hepatocyte ballooning and steatosis. There was a positive mutual correlation between hepatic FGF21 and omentin-1 mRNA levels (r = 0.78; P < 0.001). Fibrosis stage was associated with serum glucose and homeostatic model assessment for insulin resistance (HOMA-IR) (P = 0.03 and P = 0.02, respectively). Serum omentin-1 was not associated with histopathological features. The hepatic omentin-1 mRNA levels showed a tendency to be lower in patients with advanced steatosis and hepatocyte ballooning. In conclusion, our study, which focused on hepatic FGF21 and omentin-1 mRNA expression, confirmed marked expression of both molecules in the liver of morbidly obese patients with NAFLD. More extensive steatosis was associated with evident changes in the serum FGF21 concentration in morbidly obese women with NAFLD, but the difference did not reach statistical significance. The vast amount of fat, both visceral and subcutaneous, in severely obese patients may be the additional source and influence the FGF21 and omentin-1 serum levels.