357 research outputs found
Wastewater reuse in agriculture in the outskirts of the city Batna (Algeria)
The study is based on a survey of farmers. The data collected allow us to understand the reasons for the reuse of wastewater. This resource can be an important element in irrigation water management strategy. The possibilities of wastewater reuse in agriculture are significant, as is the case in the Batna region. In this context, the presence of texts establishing the modality of wastewater reuse, are a prerequisite for promotion of wastewater reuse projects. Policymakers are faced with the need to exploit the increase in volumes to meet greater demand. To do this, the integrated management should be considered now as a public / private partnership model and as the best approach for development and efficient and sustainable management.Keywords: Farmers, Irrigation, Management, Public Policy, Text
Numerical simulation of brittle damage in concrete specimens
A framework for damage mechanics of concrete
is applied to simulate the non-linear elastic
deformation behavior of concrete using
finite element method (FEM). A rather simple
isotropic damage model containing essentially
no adjustable parameters is shown to produce
results in remarkably good agreement with sample
experimental data: the damage law requires
only the fracture energy to be defined completely.
The model is achieved by introducing a
damage surface that is similar to the yield function
in the conventional theory of plasticity. A
special form of damage surfaces is constructed
to illustrate the application of the model. A new
damage criterion, defined as an equivalent
strain norm, is proposed, in order to take into
consideration the asymmetric behavior of concrete.
For verifying the FEM program including
the model, deformations predicted by this
model are compared with both the experimental
ones for the concrete structural model and
the ones calculated without application of the
continuum damage mechanics.Запропоновано критерій руйнування конструкцій з бетону, що отримав назву
норми еквівалентних деформацій. Критерій дозволяє враховувати асиметричну
механічну поведінку бетону при розтязі та стиску. Розроблено ізотропну
модель, що базується на використанні поверхні пошкодження, яка аналогічна
функції плинності теорії пластичності. За допомогою запропонованої
моделі виконано скінченноелементний розрахунок нелінійно-пружної деформації
зразків із бетону. Проведено порівняння отриманих результатів з експериментальними.
Установлено, що точність розрахунків більш висока, аніж
прогнози без використання підходів механіки пошкодження твердого тіла.Предложен критерий повреждения конструкций из бетона, получивший название нормы
эквивалентных деформаций, который позволяет учитывать асимметричное механическое
поведение бетона при растяжении и сжатии. Разработана изотропная модель, базирующаяся
на использовании поверхности повреждения, аналогичной функции течения теории
пластичности. С помощью предложенной модели выполнен конечноэлементный расчет
нелинейно-упругой деформации образцов из бетона. Проведено сравнение полученных результатов
с экспериментальными. Показана хорошая корреляция между расчетными и экспериментальными
результатами. Установлено, что точность расчетов более высокая по
сравнению с прогнозами, выполненными без применения подходов механики повреждения
твердого тела
Evaluation of the Radiation-Protective Properties of Bi (Pb)–Sr–Ca–Cu–O Ceramic Prepared at Different Temperatures with Silver Inclusion
The influences of the sintering process and AgNO3 addition on the phase formation and radiation shielding characteristics of Bi1.6Pb0.4Sr2Ca2Cu3O10 were studied. Three ceramics (code: C0, C1, and C2) were prepared as follows: C0 was obtained after calcination and only one sintering step, C1 was obtained after calcination and two sintering cycles, and C2 was prepared after the addition of AgNO3 at the beginning of the final sintering stage. C2 displayed the maximum volume fraction of the Bi-2223 phase (76.4 vol%), the greatest crystallite size, and high density. The linear mass attenuation coefficient (µ) has been simulated using the Monte Carlo simulation. The µ values are high at 15 keV (257.2 cm−1 for C0, 417.57 cm−1 for C1, and 421.16 cm−1 for C2), and these values dropped and became 72.58, 117.83 and 133.19 cm−1 at 30 keV. The µ value for the ceramics after sintering is much higher than the ceramic before sintering. In addition, the µ value for C2 is higher than that of C1, suggesting that the AgNO3 improves the radiation attenuation performance for the fabricated ceramics. It was demonstrated that the sintering and AgNO3 addition have a considerable influence on the ceramic thickness required to attenuate the radiation. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project (PNURSP2022R2), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
Superdeformed rotational bands in the Mercury region; A Cranked Skyrme-Hartree-Fock-Bogoliubov study
A study of rotational properties of the ground superdeformed bands in \Hg{0},
\Hg{2}, \Hg{4}, and \Pb{4} is presented. We use the cranked
Hartree-Fock-Bogoliubov method with the {\skm} parametrization of the Skyrme
force in the particle-hole channel and a seniority interaction in the pairing
channel. An approximate particle number projection is performed by means of the
Lipkin-Nogami prescription. We analyze the proton and neutron quasiparticle
routhians in connection with the present information on about thirty presently
observed superdeformed bands in nuclei close neighbours of \Hg{2}.Comment: 26 LaTeX pages, 14 uuencoded postscript figures included, Preprint
IPN-TH 93-6
Multi-decadal modulations in the Aleutian-Icelandic Low seesaw and the axial symmetry of the Arctic Oscillation signature, as revealed in the 20th century reanalysis
Seesaw relationship in intensity between the surface Aleutian and Icelandic Lows (AIS) is a manifestation of atmospheric teleconnection that bridges the interannual variability over the Pacific and Atlantic in particular winter months. Analysis of the 20th Century Reanalysis data reveals that the strength and timing of AIS have undergone multi-decadal modulations in conjunction with those in structure of the Arctic Oscillation (AO) signature, extracted in the leading mode of interannual sea-level pressure (SLP) variability over the extratropical Northern Hemisphere. Specifically, events of what may be called ‘pure AO’, in which SLP anomalies exhibit a high degree of axial symmetry in association with in-phase SLP variability between the midlatitude Atlantic and Pacific, tended to occur during multi-decadal periods in which the inter-basin teleconnection through AIS was active under the enhanced interannual variability of the Aleutian Low. In contrast, the axial symmetry of the AO pattern was apparently reduced during a multi-decadal period in which the AIS teleconnection was inactive under the weakened interannual variability of the Aleutian Low. In this period, the leading mode of interannual SLP variability represented a meridional seesaw between the Atlantic and Arctic, which resembles SLP anomaly pattern associated with the cold-ocean/warm-land (COWL) temperature pattern. These multi-decadal modulations in interannual AIS signal and the axial symmetry of the interannual AO pattern occurred under multi-decadal changes in the background state that also represented the polarity changes of the COWL-like anomaly pattern
Molecular analysis of HBV genotypes and subgenotypes in the Central-East region of Tunisia
<p>Abstract</p> <p>Background</p> <p>In Tunisia, country of intermediate endemicity for Hepatitis B virus (HBV) infection, most molecular studies on the virus have been carried out in the North of the country and little is known about other regions. The aim of this study was to determine HBV genotype and subgenotypes in Central-East Tunisia. A total of 217 HBs antigen positive patients were enrolled and determination of genotype was investigated in 130 patients with detectable HBV DNA. HBV genotyping methods were: PCR-RFLP on the pre-S region, a PCR using type-specific primers in the S region (TSP-PCR) and partial sequencing in the pre-S region.</p> <p>Results</p> <p>Three genotypes (D, B and A) were detected by the PCR-RFLP method and two (D and A) with the TSP-PCR method, the concordance between the two methods was 93%. Sequencing and phylogenetic analysis of 32 strains, retrieved the same genotype (D and A) for samples with concordant results and genotype D for samples with discordant results. The sequences of discordant genotypes had a restriction site in the pre-S gene which led to erroneous result by the PCR-RFLP method. Thus, prevalence of genotype D and A was 96% and 4%, respectively. Phylogenetic analysis showed the predominance of two subgenotypes D1 (55%) and D7 (41%). Only one strain clustered with D3 subgenotype (3%).</p> <p>Conclusions</p> <p>Predominance of subgenotype D7 appears to occur in northern regions of Africa with transition to subgenotype D1 in the East of the continent. HBV genetic variability may lead to wrong results in rapid genotyping methods and sequence analysis is needed to clarify atypical results.</p
Annealing study and thermal investigation on bismuth sulfide thin films prepared by chemical bath deposition in basic medium
This is a post-peer-review, pre-copyedit version of an article published in Applied Physics A 124.2 (2018): 166. The final authenticated version is available online at: http://doi.org/10.1007/s00339-018-1584-7Bismuth sulfide thin films were prepared by chemical bath deposition using thiourea as sulfide ion source in basic medium. First, the effects of both the deposition parameters on films growth as well as the annealing effect under argon and sulfur atmosphere on as-deposited thin films were studied. The parameters were found to be influential using the Doehlert matrix experimental design methodology. Ranges for a maximum surface mass of films (3 mg cm-2) were determined. A well crystallized major phase of bismuth sulfide with stoichiometric composition was achieved at 190°C for 3 hours. The prepared thin films were characterized using Grazing Incidence X-ray diffraction (GIXRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX). Second, the band gap energy value was found to be 1.5 eV. Finally, the thermal properties have been studied for the first time by means of the electropyroelectric (EPE) technique. Indeed, the thermal conductivity varied in the range of 1.20 - 0.60 W m-1 K-1 while the thermal diffusivity values increased in terms of the annealing effect ranging from 1.8 to 3.5 10-7 m2s-1This work was financially
supported by the Tunisian Ministry of Higher Education and Scientific
Research and by the WINCOST (ENE2016-80788-C5-2-R) project
funded by the Spanish Ministry of Economy and Competitivenes
Evaluating ENSO teleconnections using observations and CMIP5 models
Bias correction of global and regional climate models is essential for credible climate change projections. This study examines the bias of the models of the Coupled Model Inter-comparison Project Phase 5 (CMIP5) in their simulation of the spatial pattern of sea surface temperature (SSTs) in different phases of the El Niño Southern Oscillation (ENSO) and their teleconnections—highlighting the strengths and weaknesses of the models in different oceanic sectors. The comparison between the model outputs and the observations focused on the following three features: (i) the typical horseshoe pattern seen in the Pacific Ocean during ENSO events with anomalies in SSTs opposite to the warm/cool tongue, (ii) different signature in the tropical Pacific Ocean from that of the North and tropical Atlantic Ocean, and (iii) spurious signature in the southern hemisphere beyond 45° S. Using these three cases, it was found that the model simulations poorly matched the observations, indicating that more attention is needed on the tropical/extratropical teleconnections associated with ENSO. More importantly, the observed SST coupling between the tropical Pacific Ocean and the Atlantic Ocean is missing in almost all models, and differentiating the models between high/low top did not improve the results. It also found that SSTs in the tropical Pacific Ocean are relatively well simulated when compared with observation. This work has improved our understanding of the simulation of ENSO and its teleconnections in the CMIP5 models and has raised awareness of the bias existing in the models, which requires further attention by climate modellers. © 2018 The Author(s
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