The impact of azimuthally asymmetric carbon deposition upon pellet-clad mechanical interaction in advanced gas reactor fuel

Cracked nuclear fuel pellets were modelled in the r-θ plane with an azimuthally varying clad surface temperature boundary condition using the PELICAN set of fuel performance models for the commercial finite element software, Abaqus. The temperature boundary condition was assumed to represent heat transfer impairment due to an azimuthally asymmetric carbon deposit on advanced gas-cooled reactor pins. The model predicts the radial and azimuthal displacement of the idealised fuel fragments, together with the resulting elastic, creep and plastic strains in the cladding. These were compared to simulations assuming a uniformly hot or cold boundary condition. Apart from a short period during the return to power from reduced power (70%) operation and outages, the hoop stress in the simulation with an azimuthally varying clad surface temperature was bounded by that of models with a uniform hot or cold surface temperature. The reduced stress was proposed to be due to the greater ability of the fuel fragments to relocate in order to accommodate changes to the power level. As a result, the creep strains in the model with an azimuthally varying clad surface temperature were lower than assuming either a uniform hot or cold boundary condition

Влияние масла виноградных косточек на некоторые показатели окислительного стресса у больных язвенной болезнью двенадцатиперстной кишки

Catedra Farmacologie şi farmacologie clinică, Catedra Boli interne nr. 6, Centrul Ştiinţific în Domeniul Medicamentului, USMF „Nicolae Testemiţanu”, Conferinţa Ştiinţifico-Practică „Medicina modernă, actualităţi şi perspective”, consacrată aniversării de 40 de ani ai Spitalului Clinic al Ministerului Sănătăţii, 27-28 mai, 2010, Chişinău, Republica MoldovaThe study analyzed 50 duodenal ulcer patients regarding the influence of grape seed oil in association with the standard triple therapy Omeprazole-Metronidazole-Clarithromycin on the dynamics of clinical manifestations, morpho-functional changes of the gastroduodenal zone mucosa. The patients were divided into 2 groups according to the treatment schemes: group I patients (n = 25) were given Omeprazole, Clarithromycin and Metronidazole, while those in group II (n = 25) supplemented the same treatment with grapes seeds oil for 14 days. Grape seed oil, used in complex treatment of duodenal ulcer, contributed to a more rapid reduction of the lipid peroxidation and increased the total antioxidant activity in gastric mucosa compared with the standard triple treatment.Изучено влияние масла виноградных косточек на динамику клинических проявлений и морфо-функциональных изменений слизистой оболочки гастродуоденальной зоны у 50 больных язвенной болезнью двенадцатиперстной кишки на фоне стандартной тройной терапии. В зависимости от схемы терапии пациенты были разделены на 2 группы: больные I группы (n = 25) получали омепразол, кларитромицин и метронидазол, больные II группы (n = 25) –дополнительно к той же схеме получали масло виноградных косточек в течение 14 дней. Масло виноградных косточек, используемое в комплексном лечении пациентов язвенной болезнью с локализацией язвы в двенадцатиперстной кишке, способствовало более быстрому снижению липопероксидации и повышению антиоксидантной активности слизистой оболочки желудка по сравнению со стандартной тройной схемой лечения

Минеральные воды и их рациональное использование в гастроэнтерологии и гепатологии

Department of Pharmacology and Clinical Pharmacology, Nicolae Testemitanu State Medical and Pharmaceutical University, Congresul III al Medicilor de Familie din Republica Moldova, 17–18 mai, 2012, Chişinău, Republica Moldova, Conferinţa Naţională „Maladii bronhoobstructive la copii”, consacrată profesorului universitar, doctor habilitat Victor Gheţeul, 27 aprilie, Chişinău, Republica MoldovaThe rational utilization of mineral water in gastroenterology and hepatology is based on the study of the medicinal and prophylactic properties depending on the composition, mineral degree, and the effects of its components. Type, volume, and temperature of the mineral water determine the dosage regime in the stomach, gut, liver, and biliary duct’s pathologies.Рациональное применение минеральных вод в гастроэнтерологии и гепатологии основано на изучении лечебных и профилактических эффектов в зависимости от состава, степени минерализации и эффектов компонентов. Тип, объём, и температура минеральной воды определяют режим дозирования при соответствующей патологии желудка, кишечника, печени и желчевыводящих путей

Отечественный препарат Биозар – эффективное средство в лечении стеатогепатита

Department of Internal Medicine, Medical Clinic of Occupational Diseases Nicolae Testemitanu State Medical and Pharmaceutical UniversityThe local drug Biozar – an efficient remedy in the treatment of steatohepatitis 60 patients with non-alcoholic steatohepatitis associated with acalculous cholecystitis were randomly grouped according to the type of treatment. The study group consisted of 35 patients who received local standard therapy and Biozar and the control group, 25 patients who received only standard therapy. In the 8-week program the complex treatment coupled with Biozar showed a positive influence on the dyspeptic and pain syndromes, each showing a severity status 1,2 times lower than the control group, clearly improved liver function and normalized the lipid components helping to reduce the aterogenity index. В исследование были включены 60 пациентов с неалкогольным стеатогепатитом ассоциированным с калькулезным холециститом. В зависимости от применяемого лечения методом случайного отбора, больные были разделены на две группы: основная – 35 пациентов, которые получали базисную терапию и Biozar; контрольная группа – 25 пациентов, которые получали только базисную терапию. Лечение продолжалось в течение 8 недель. Комплексное лечение с включением Biozar повлияло более значимо на болезненный и диспепсический синдромы (средняя степень тяжести обоих синдромов было в 1,2 раза ниже по сравнению с контрольной группой), что способствовало улучшению функционального состояния печени и коррекции липидных компонентов сыворотки, что способствовало достоверному уменьшению индекса атерогенности

Atomic scale simulation of the strain rate and temperature dependence of crack growth and stacking faults in zirconium

Molecular dynamics simulations of single crystal zirconium fracture were performed to study the deformation mechanisms active on the basal and prismatic planes. The effects of temperature (0 to 300 K) and strain rate (108–1010 s −1 ) were investigated. Crack tip orientation was found to strongly affect the fracture behaviour. On the basal plane twinning ({11¯21}) and emission of type dislocations that then dissociated into partial dislocations around pyramidal I2 stacking faults were seen to occur during fracture. At higher strain rates (109 and 1010 s −1 ), twinning occurred. The emission of edge dislocations ( 1 3 type) was prevalent on the prismatic plane and were found to be strongly affected by temperature. At higher temperature (150 and 300 K), the dislocation density increased. The crack grew further at 150–300 K than at 0 K and the shielding effect of dislocations was limited due to their movement away from the crack tip. The addition of iodine at basal I2, pyramidal I1 and I2 stacking faults was seen to decrease the energy of its formation whereas for the prismatic stacking fault it was found to increase it. The iodine also changed the order of favourability of the stacking faults with basal I2 and pyramidal I1 stacking faults becoming much more favourable and prismatic going from most to least favourable

Atomistic modelling of iodine-oxygen interactions in strained sub-oxides of zirconium

In water reactors, iodine stress corrosion cracking is considered the cause of pellet-cladding interaction failures, but the mechanism and chemistry are debated and the protective effect of oxygen is not understood. Density functional theory calculations were used to investigate the interaction of iodine and oxygen with bulk and surface Zr under applied hydrostatic strain (2% to +3%) to simulate crack tip conditions in Zr to ZrO, using a variety of intermediate suboxides (ZrO, ZrO, ZrO and ZrO). The formation energy of an iodine octahedral interstitial in Zr was found to decrease with increasing hydrostatic strain, whilst the energy of an iodine substitutional defect was found to be relatively insensitive to strain. As the oxygen content increased, the formation energy of an iodine interstitial increased from 1.03 eV to 8.61 eV supporting the idea that oxygen has a protective effect. At the same time, a +3% tensile hydrostatic strain caused the iodine interstitial formation energy to decrease more in structures with higher oxygen content: 4.56 eV decrease in ZrO compared to 1.47 eV decrease for pure Zr. Comparison of the substitutional and interstitial energies of iodine, to the adsorption energy of iodine, in the presence of oxygen, shows the substitutional energy of iodine onto a Zr site is more favourable for all strains and even interstitial iodine is favourable between strains of +1-5%. Although substitutional defects are preferred to octahedral interstitial defects, in the ordered suboxides, a 3% tensile strain significantly narrows the energy gap and higher strains could cause interstitial defects to form

Atomistic modelling of iodine-oxygen interactions in strained sub-oxides of zirconium

In water reactors, iodine stress corrosion cracking is considered the cause of pellet-cladding interaction failures, but the mechanism and chemistry are debated and the protective effect of oxygen is not understood. Density functional theory calculations were used to investigate the interaction of iodine and oxygen with bulk and surface Zr under applied hydrostatic strain (-2 % to +3 %) to simulate crack tip conditions in Zr to ZrO, using a variety of intermediate suboxides (ZrO, ZrO, ZrO and ZrO). The formation energy of an iodine octahedral interstitial in Zr was found to decrease with increasing hydrostatic strain, whilst the energy of an iodine substitutional defect was found to be relatively insensitive to strain. As the oxygen content increased, the formation energy of an iodine interstitial increased from 1.03 eV to 8.61 eV supporting the idea that oxygen has a protective effect. At the same time, a +3 % tensile hydrostatic strain caused the iodine interstitial formation energy to decrease more in structures with higher oxygen content: 4.56 eV decrease in ZrO compared to 1.47 eV decrease for pure Zr. Comparison of the substitutional and interstitial energies of iodine, to the adsorption energy of iodine, in the presence of oxygen, shows the substitutional energy of iodine onto a Zr site is more favourable for all strains and even interstitial iodine is favourable between strains of +1-5%. Although substitutional defects are preferred to octahedral interstitial defects, in the ordered suboxides, a 3 % tensile strain significantly narrows the energy gap and higher strains could cause interstitial defects to form