1,416 research outputs found
Parareal in time 3D numerical solver for the LWR Benchmark neutron diffusion transient model
We present a parareal in time algorithm for the simulation of neutron
diffusion transient model. The method is made efficient by means of a coarse
solver defined with large time steps and steady control rods model. Using
finite element for the space discretization, our implementation provides a good
scalability of the algorithm. Numerical results show the efficiency of the
parareal method on large light water reactor transient model corresponding to
the Langenbuch-Maurer-Werner (LMW) benchmark [1]
Agronomic Performance and Nutraceutical Quality of a Tomato Germplasm Line Selected under Organic Production System
Organic tomato production is increasing worldwide, thus making necessary the development of varieties adapted to this farming system. It is now well known that the implementation of local tomato plant breeding programs for organic farming is required to increase the performance of varieties in this typology of cultivation regime. In this research, the agronomic performance, nutraceutical contents, and radical scavenging activity of a tomato germplasm line (OSTGL), selected under organically grown conditions, were evaluated for two consecutive years (2018 and 2019) in comparison with the variety ‘Rio Grande’, frequently grown organically in Tunisia. Carotenoids, phenolics, vitamin C, and radical scavenging capacity were assayed spectrophotometrically, while tocopherols were analyzed by HPLC. All data were not affected by year-to-year variability. The OSTGL line showed significantly higher marketable yield, total phenol, flavonoid, vitamin C, α-tocopherol and γ-tocopherol contents, along with radical scavenging activity. The OSTGL red-ripe berries also showed comparable values for average weight, soluble solids, pH, titratable acidity, firmness and coloration, as well as lycopene and β-carotene contents. This open pollinated tomato germplasm line demonstrated to be an effective sustainable variety for improving fruit yield, agronomic, and nutraceutical characteristics under an organic management system
Synthesis of Single-Phase Anatase TiO2 Nanoparticles by Hydrothermal Treatment
Pure anatase powders of titanium dioxide with a homogeneous nanosized particles distribution were
prepared by a facile hydrothermal route using solution of acetic acid and tetraisopropyl orthotitanate as
the precursors with a molar ratio of 1:1. The modified hydrolyzed alkoxide was treated at various temperatures under different autogenic pressures. Two different reactors were employed as autoclaves for heating
and generation of high pressures during the synthesis and crystallization of TiO2 nanoparticles. The characteristics of TiO2 powders obtained under various synthesis conditions were verified using X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FE-SEM). The results indicated that particles size of the formed TiO2 could be finely tuned by varying the experimental parameters of temperature,
pressure and the amount of nitric acid in the peptization step. TiO2 nanoparticles with good dispersion and
mean size of about 9 nm could be seen in FE-SEM image of sample synthesized under temperature of 160
°C for 12 h using more nitric acid in the peptization step.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3488
Biomass variation in red algae along the tidal areas of Bushehr province
This study was carried out during October 2008 to July 2009 in Bushehr coastal areas at 6 stations to examine biomass variations in red algae. Algal samples were collected by hand from intertidal zone, during low tide. Quadrates 50 ×50cm each were marked randomly in the study area, and all algal samples were collected within the quadrate area. Total biomass was found to be 2598.91g. m belonging to 15 Rhodophyta species. The maximum biomass was 1114.32g. m (43%) observed at the Nirougah station. Summer showed maximum biomass 1076.36g. m (41%) compared to other seasons. Results of this study showed Rhodophyta species are dispersed more in mid littoral and sub-tidal areas. Also, the maximum biomass was observed in the sub-tidal zone. The highest biomass of the species belonged to Gracilaria canaliculata
Investigation of Punching Parameters Effect on Mechanical Properties of Al-1100-O in Incremental Sheet Metal Hammering Process
Процесс штамповки является быстрым и технологичным способом производства изделий из листовых материалов. Его инновационный вариант – последовательная штамповка листовых металлов – обеспечивает штамповку трехмерного изделия путем его последовательного выдавливания пуансоном из исходного листа без применения ответной матрицы. Исследуется влияние диаметра пуансона и частоты его приложения на механические свойства листового сплава Al-1100-O (твердость, прочность при растяжении, размеры и ориентация зерен). Показано, что с уменьшением диаметра пуансона и повышением частоты его приложения увеличиваются твердость и прочность материала после штамповки. Для оценки его механических свойств указанным методом успешно применяются две статистические модели.Процес штампування є швидким і технологічним способом виготовлення виробів із листових матеріалів. Його інноваційний варіант – послідовне штампування листових металів – забезпечує штампування тривимірного виробу шляхом його послідовного видавлювання пуансоном із вихідного листа без застосування відповідної матриці. Досліджується вплив діаметра пуансона і частоти його прикладення на механічні властивості листового сплаву Al-1100-O (твердість, міцність при розтязі, розміри й орієнтація зерен). Показано, що зі зменшенням діаметру пуансона і підвищенням частоти його прикладання збільшуються твердість і міцність матеріалу після штампування. Для оцінки його механічних властивостей зазначеним методом успішно використовуються дві статистичні моделі
What do near-term observations tell us about long-term developments in greenhouse gas emissions? A letter
Long-term scenarios developed by integrated assessment models are used in climate research to provide an indication of plausible long-term emissions of greenhouse gases and other radiatively active substances based on developments in the global energy system, land-use and the emissions associated with these systems The phenomena that determine these long-term developments (several decades or even centuries) are very different than those that operate on a shorter time-scales (a few years) Nevertheless, in the literature, we still often find direct comparisons between short-term observations and long-term developments that do not take into account the differing dynamics over these time scales In this letter, we discuss some of the differences between the factors that operate in the short term and those that operate in the long term We use long-term historical emissions trends to show that short-term observations are very poor indicators of long-term future emissions developments Based on this, we conclude that the performance of long-term scenarios should be evaluated against the appropriate, corresponding long-term variables and trends The research community may facilitate this by developing appropriate data sets and protocols that can be used to test the performance of long-term scenarios and the models that produce the
Aviram-Ratner rectifying mechanism for DNA base pair sequencing through graphene nanogaps
We demonstrate that biological molecules such as Watson-Crick DNA base pairs
can behave as biological Aviram-Ratner electrical rectifiers because of the
spatial separation and weak hydrogen bonding between the nucleobases. We have
performed a parallel computational implementation of the ab-initio
non-equilibrium Green's function (NEGF) theory to determine the electrical
response of graphene---base-pair---graphene junctions. The results show an
asymmetric (rectifying) current-voltage response for the Cytosine-Guanine base
pair adsorbed on a graphene nanogap. In sharp contrast we find a symmetric
response for the Thymine-Adenine case. We propose applying the asymmetry of the
current-voltage response as a sensing criterion to the technological challenge
of rapid DNA sequencing via graphene nanogaps
Body composition, blood pressure and dietary habits among young qatari male adults
Introduction: Due to a rapidly changing lifestyle in Qatar, determinants of non-communicable diseases and linked levels of risk factors have risen. These facts pose a national challenge (1). Information about Qatari adults` (19-30yr.) dietary habits is essential because of the increase in the incidence and prevalence of obesity in Qataris. In 2006, the percentage of Qatari boys who are overweight and obese is 28.6%, and 7.9%, respectively (3). Aim of this study was to determine body composition, blood pressure and dietary habits of the next cohort, those 18-29 yrs old.
Methods: 80 Qatari male students, 18-29 yrs of age, from Qatar University (QU) participated. Blood pressure (BP) was measured by Omron HEM-780, body composition (body weight and percent of body fat (BF), were measured by OMRON BF-400. Dietary habits were evaluated using the NHANES Food Frequency Questionnaire. For data analysis, Chi-square test and univariate analyses of variance were conducted using SPSS version 20.
Results: The mean systolic and diastolic BP was 128.6±1.42 mmHg, 73.32±1.1 mmHg, respectively. The mean arterial pressure (MAP) was 91.74±1.06 mmHg. The mean BF is 23.79±1.19%. 30.77% of the subjects were classified as overweight, 38.46% as obese. The crosstab statistical analyses yielded a difference between fast food (FF) vs. seafood (SF) consumptions (p=.007). No statistical difference between vegetables consumption vs. pasta intake occur. However, the subjects` soda consumption was greater than fruit juices (p=.05). The BF is expressed by an interaction between salad and SF consumption, p=.047, ηp2=.409, but these main effects are not qualified by a separate interaction on BF (p=.234, ηp2=.181 vs. p=.34, ηp2=.149, respectively). No interaction was found between FF, SF or sweets and blood pressure values.
Conclusion: Obesity is uniformly considered to be the most important factor in developing non-communicable diseases in Qatar (2). Our study supports the results. In our sample, the prevalence of overweight and obesity was higher compared to previously published studies. No correlation between dietary habits and MAP occurred though, due to the wide range of nutrients consumed. High caloric diets are prevalent among QU students
Maladie de castleman multicentrique: A propos d’un cas
La maladie de Castleman est une affection rare, d’étiologie inconnue, caractérisée sur le plan histologique par une hyperplasie lymphoïde angiofolliculaire. Elle se présente sous deux formes différentes, localisée et multicentrique. Nous rapportons une observation de maladie de Castleman chez un homme de 69 ans qui avait consulté pour des adénopathies cervicales chroniques. Il s’agissait d’une forme multicentrique d’évolution rapidement fatale malgré un traitement agressif associant corticothérapie et chimiothérapie.Mots clès : Hyperplasie lymphoïde angio-folliculaire, adénopathie cervicale, maladie de Castleman, lymphome
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