Performance de voussoirs de tunnel préfabriqués en béton armé d’armatures en PRFV sous charge de flexion cyclique quasi-statique

Les dispositions de conception actuelles dans les normes ne sont pas applicables à la conception de voussoirs de revêtement de tunnels en béton préfabriqué (RTBP) armé d’armature en polymère renforcé de fibres de verre (PRFV). La résistance et le comportement des voussoirs de revêtements de tunnels en béton préfabriqué (RTBP) armé d’armature en PRFV sous des charges de flexion cyclique quasi-statique est un domaine dans lequel aucun résultat de recherche expérimentale n'est disponible. Un total de douze voussoirs de RTBP à pleine échelle ayant une longueur de 3100 mm, une largeur de 1500 mm et une épaisseur de 250 mm ont été construits et testés sous des charges de flexion cycliques quasi-statiques. Deux cycles de chargement et de déchargement ont été appliqués à 1,25%, 2,5%, 5%, 10%, 25%, 50% et 75% du déplacement maximal estimé, suivis d'un seul cycle de chargement jusqu'à la rupture. Les paramètres de l'essai comprenaient le type d’armature (armature en PRFV et d’acier), le taux d’armature longitudinal, la résistance à la compression du béton (béton à haute résistance (BHR) et béton à résistance normale (BRN)), le type de béton (béton renforcé de fibres (BRF) par rapport au BRN), et la configuration de l’armature transversale (cadres fermés par rapport aux cadres doubles en forme de U). La réponse d'hystérésis, le modèle de fissuration, la déformation résiduelle, l'énergie dissipée, l'indice de ductilité, la déformabilité et l'indice de dommage de la rigidité sécante des spécimens testés ont été définis et évalués. Les résultats expérimentaux de l'étude montrent la faisabilité de l'utilisation de barres en PRFV au lieu de barres d’acier pour les voussoirs de RTBP sous des charges de flexion cycliques quasi-statiques. De plus, les résultats expérimentaux montrent l'efficacité de l'utilisation de BHR et BRF par rapport au BRN pour les applications de voussoirs de RTBP armé d’armature en PRFV. Une prédiction théorique selon les diverses dispositions de conception actuelles - y compris la résistance en flexion, la résistance à l’effort tranchant, le moment de fissuration et la prédiction de largeur de fissure des voussoirs de RTBP - a été effectuée incluant une comparaison aux résultats expérimentaux. En outre, utilisant l'approche itérative couche par couche, un modèle analytique a été présenté pour la réponse d'hystérésis des voussoirs de RTBP armé d’armature de PRFV sous des charges de flexion cycliques quasi-statiques. De plus, des modèles analytiques pour la rigidité tangente de chargement après fissuration et la rigidité de déchargement pour les voussoirs en RTBP armé d’armature de PRFV ont été proposés. Les modèles analytiques montrent IV des prédictions précises avec une rigidité de chargement, une rigidité de déchargement et une déformation résiduelle comparables à la fin de chaque cycle de chargement.Abstract: Current design provisions are not applicable to designing precast concrete tunnel lining (PCTL) segments reinforced internally with fiber-reinforced polymer (FRP) bars. The strength and behavior of segments of precast concrete tunnel linings (PCTLs) reinforced internally with FRP bars under quasi-static cyclic flexural loading is one area in which no experimental research results are available. A total of twelve full-scale PCTL segments with a total length, width, and thickness of 3100 mm, 1500 mm, and 250 mm, respectively, were constructed and tested under quasi-static cyclic flexural loading. Two cycles of loading and unloading were applied at 1.25%, 2.5%, 5%, 10%, 25%, 50%, and 75% of the estimated maximum displacement, followed by a single cycle up to failure. The test parameters included reinforcement flexural stiffness (GFRP versus steel), GFRP longitudinal reinforcement ratio, the concrete compressive strength (high-strength concrete (HSC) versus normal-strength concrete (NSC)), the concrete type (fiber-reinforced concrete (FRC) versus NSC), and the transverse reinforcement configuration (closed versus double U-shaped ties). The hysteresis response, cracking pattern, residual deformation, dissipated energy, ductility index, deformability, and secant stiffness damage index of the tested specimens, under the quasi-static cyclic flexural loading, were defined, estimated, and evaluated. The experimental results of the study show the feasibility of using GFRP bars instead of steel bars for PCTL segments under quasi-static cyclic flexural loading. Moreover, the experimental results show the effectiveness of using HSC and FRC over the NSC for the GFRP-reinforced PCTL segment applications. A theoretical prediction according to the various current design provisions – including the flexural capacities, the shear capacities, the cracking moments, and the crack-width predictions of the PCTL segments – was carried out and compared to the experimental results. Furthermore, using the layer-by-layer iterative approach, an analytical model was presented for the hysteresis response of the GFRP-reinforced PCTL segments under quasi-static cyclic flexural loading. In addition, analytical models for the post-cracking loading tangent stiffness and the unloading stiffness for the GFRP reinforced PCTL segments were proposed. The analytically predicted models show accurate predictions with comparable loading stiffness, unloading stiffness and residual deformation at the end of each loading cycles

"Biosynthesis of silver nanoparticles from Staphylococcus lentus isolated from Ocimum basilicum and their antibacterial activity"

The present study was isolated and identification of endophytic bacteriumisolated from Ocimum basilicum by surface sterilization method. Bacterial strain was identifiedas Sphylococcus lentus.Bacterium isolate was used to detect their ability toprepare silver nanoparticles. The results showed change in color silver nitrate solution 1mM brown, studied the spectrum of absorption of UV, visible spectroscopy of the solution silver particles nano second stepin making sure the formation of particles and found to be located on the wavelength of 400 nm to bacteriaOcimum basilicumalso show that the X-ray diffraction peak was at (103) and at the angle (34.1). Additinary the results showed clear images in the scanning electron microscope size and shape, Size ranged between20.4 -93.04nm.The results revealed thatbAgNPs synthesized from Sphylococcus lentus. have antibacterial activity against Gram-negativeEscherichia coli, Gram-positive Staphylococcus aureu

Estimating the Concentration of Cadmium in the Qayyarah and Kasak Sites and its Impact on the Environment

Cadmium recorded a significant superiority in the soil of the Qayyarah site with a peak of (491.744) mg/kg compared to the Kasak site, which showed its highest concentration in the soil of (D1) at (0) metres. The highest value was recorded at (520.217) mg/kg, which indicates high pollution. Compared to the rest of the dimensions, the lowest concentration of cadmium was in the soil (D2) at a distance of (50) meters, amounting to (428,050) mg/kg. While we note that the Qayyarah site recorded the lowest values of cadmium at the distance (S2D2) (50 metres), with a concentration rate of (450.867) mg/kg. As for cadmium, its highest concentration was at the distance (S2D3) (100 metres) and (S2D5). It reached (521.867) mg/kg. While the Kasak site recorded the highest value of cadmium at a distance of (S1D1) (0 metres) with a concentration of (527.667) mg/kg, while the lowest concentration of cadmium was at point (S1D2) (50 metres) with a value of (405.233) mg/kg

Queueing Analysis of a Priority-based Claim Processing System

We propose a situation in which a single employee is responsible for processing incoming claims to an insurance company that can be classified as being one of two possible types. More specifically, we consider a priority-based system having separate buffers to store high priority and low priority incoming claims. We construct a mathematical model and perform queueing analysis to evaluate the performance of this priority-based system, which incorporates the possibility of claims being redistributed, lost, or prematurely processed

On the effective reconstruction of expectation values from ab initio quantum embedding

Quantum embedding is an appealing route to fragment a large interacting quantum system into several smaller auxiliary `cluster' problems to exploit the locality of the correlated physics. In this work we critically review approaches to recombine these fragmented solutions in order to compute non-local expectation values, including the total energy. Starting from the democratic partitioning of expectation values used in density matrix embedding theory, we motivate and develop a number of alternative approaches, numerically demonstrating their efficiency and improved accuracy as a function of increasing cluster size for both energetics and non-local two-body observables in molecular and solid state systems. These approaches consider the $N$-representability of the resulting expectation values via an implicit global wave~function across the clusters, as well as the importance of including contributions to expectation values spanning multiple fragments simultaneously, thereby alleviating the fundamental locality approximation of the embedding. We clearly demonstrate the value of these introduced functionals for reliable extraction of observables and robust and systematic convergence as the cluster size increases, allowing for significantly smaller clusters to be used for a desired accuracy compared to traditional approaches in ab initio wave~function quantum embedding.Comment: 20 page

Insecticide resistance in Anopheles arabiensis (Diptera: Culicidae) from villages in central, northern and south west Ethiopia and detection of kdr mutation

<p>Abstract</p> <p>Background</p> <p><it>Anopheles arabiensis </it>is the major vector of malaria in Ethiopia. Malaria vector control in Ethiopia is based on selective indoor residual spraying using DDT, distribution of long lasting insecticide treated nets and environmental management of larval breeding habitats. DDT and pyrethroid insecticides are neurotoxins and have a similar mode of action on the sodium ion channel of insects. It was therefore necessary to verify the insecticide susceptibility status of <it>An. arabiensis</it>, to better understand the status of cross-resistance between DDT and the pyrethroids in this species as well as to detect a resistant gene.</p> <p>Methods</p> <p>Standard WHO insecticide susceptibility tests were conducted on adults reared from larval and pupal collections from breeding sites at three villages namely: Sodere in the Rift Valley, Gorgora in the north and Ghibe River Valley in the south west of Ethiopia. The occurrence of cross-resistance between pyrethroids and DDT was determined using a DDT selected laboratory colony originally collected from Gorgora. Phenotypically characterized mosquitoes were tested for the presence of knockdown resistance (<it>kdr</it>) alleles using the standard polymerase chain reaction assay.</p> <p>Results</p> <p>All <it>An. gambiae </it>s.l. specimens assayed by PCR were identified as <it>An. arabiensis</it>. The knockdown and mortality results showed <it>An. arabiensis </it>resistance to DDT in all villages, resistance to deltamethrin and permethrin in the Ghibe River Valley and permethrin resistance in Gorgora. Bioassay susceptibility tests also indicated the presence of cross-resistance between DDT and permethrin, but not between DDT and deltamethrin. The knockdown resistance <it>(kdr) </it>mutation of leucine to phenylalanine in the sodium ion channel gene was detected in populations from Gorgora and the Ghibe River Valley.</p> <p>Conclusion</p> <p>Since <it>An. arabiensis </it>shows high levels of resistance to DDT in all villages tested and varying pyrethroid resistance in Gorgora and the Ghibe River valley, precautionary measures should be taken in future vector control operations. Moreover, the status of resistance in other locations in Ethiopia and the spread of resistant gene (s) should be investigated.</p

The impact of integration between e-book and paper book on the achievement of Life Sciences Department students in computers subject and their need for knowledge.

يهدف البحث الحالي الكشف عن اثر التكامل بين الكتاب الالكتروني والكتاب الورقي في&nbsp; تحصيل طلبة قسم علوم الحياة لمادة الحاسبات وحاجتهم الى&nbsp; المعرفة، وتم تدريس مفردات مادة الحاسبات المقررة لطلبة الصفوف&nbsp; الاولى في كليات الجامعات العراقية&nbsp;&nbsp; للعام الدراسي (2018-2019) للمجموعة التجريبية الاولى باستخدام الكتاب الورقي فقط ، وللمجموعة التجريبية الثانية باستخدام الكتاب الإلكتروني فقط ،وللمجموعة التجريبية الثالثة باستخدام الكتاب الورقي والالكتروني معاً. وقد اعد الباحثان مستلزمات التجربة المتمثلة بــــــ(اشتقاق الاهداف السلوكية ،وكتابة الخطط التدريسية للمجموعات الثلاث )،كما تم اعتماد كتاب الكتروني جاهز بعد التأكد من صلاحيته. وقد أعد الباحثان اختبار تحصيلي مكون من 35 فقرة وتم التأكد من خصائصه السايكومترية، وتبنا مقياس جاهز لقياس الحاجة الى المعرفة. و استمرت التجربة العملية خمسة اشهر طبق بعدها الاختبار التحصيلي ومقياس الحاجة الى المعرفة على طلبة المجموعات الثلاث في نفس الوقت. وأظهرت نتائج التجربة&nbsp; فروق ذات دلالة احصائية في متوسطي درجات الاختبار التحصيلي والحاجة الى المعرفة لصالح المجموعة الثالثة . وفي ضوء نتائج البحث قدم الباحثان بعض التوصيات والمقترحات. الكلمات الدلالية: الكتاب الالكتروني ، الكتاب الورقي ،&nbsp; التحصيل ، مادة الحاسبات&nbsp; ،الحاجه الى&nbsp; المعرفة.This research aims to reveal the impact of the integration between e-book and paper book in the achievement of the students of the Department of Life Sciences for the subject of computers and their need for knowledge, and was taught the vocabulary of computer courses scheduled for the first grades in Iraqi university colleges for the academic year (2018-2019) for the first experimental group Using the paper book only, for the second experimental group using the e-book only, and for the third experimental group using the paper and electronic book together. The researchers have prepared the requirements of the experiment (derivation of behavioral goals, and write the teaching plans for the three groups), and was adopted a ready e-book after confirming its validity. &nbsp;&nbsp;The researchers prepared a 35-paragraph achievement test and confirmed its psychometric properties, and adopted a ready scale to measure the need for knowledge. The practical experience lasted five months, after which the achievement test and the need for knowledge scale were applied to the students of the three groups at the same time. The results of the experiment showed statistically significant differences in the average scores of achievement test and the need for knowledge in favor of the third group. In the light of the research results, the researchers presented some recommendations and suggestions. Keywords: e-book, paper book, collections, computing material, need for knowledge

Challenges Related to Epilepsy Management in Sudan, an Example of Low-Middle Income Country

Epilepsy is one of the most common neurological diseases that require long-term healthcare, although it has no racial, gender, or geographical boundaries, certain populations and demographics face different challenges regarding management of epilepsy. These challenges include patients’ and communities’ misconceptions of epilepsy nature, treatment and outcome, various use of traditional and spiritual therapy in management of epilepsy, stigma of epilepsy, shortage of neurology facilities and specialists and their aggregation in the capital, and collapse of the healthcare system in Sudan. This chapter aims to highlight some of the difficulties facing people with epilepsy in Sudan, an example of a low middle-income country

Facial image encryption for secure face recognition system

A biometric authentication system is more convenient and secure than graphical or textual passwords when accessing information systems. Unfortunately, biometric authentication systems have the disadvantage of being susceptible to spoofing attacks. Authentication schemes based on biometrics, including face recognition, are susceptible to spoofing. This paper proposes an image encryption scheme to counter spoofing attacks by integrating it into the pipeline of Linear Discriminant Analysis (LDA) based face recognition. The encryption scheme uses XOR pixels substitution and cellular automata for scrambling. A single key is used to encrypt the training and testing datasets in LDA face recognition system. For added security, the encryption step requires input images of faces to be encrypted with the correct key before the system can recognize the images. An LDA face recognition scheme based on random forest classifiers has achieved 96.25% accuracy on ORL dataset in classifying encrypted test face images. In a test where original test face images were not encrypted with keys used for encrypted feature databases, the system achieved 8.75% accuracy only showing it is capable of resisting spoofing attacks

A basic probability assignment methodology for unsupervised wireless intrusion detection

The broadcast nature of Wireless Local Area Networks (WLANs) has made them prone to several types of wireless injection attacks, such as Man-in-the-Middle (MitM) at the physical layer, deauthentication and rogue access point attacks. The implementation of novel Intrusion Detection Systems (IDSs) is fundamental to provide stronger protection against these wireless injection attacks. Because most attacks manifest themselves through different metrics, current IDSs should leverage a cross-layer approach to help towards improving the detection accuracy. The data fusion technique based on Dempster-Shafer (D-S) theory has been proven to be an efficient data fusion technique to implement the cross-layer metric approach. However, the dynamic generation of the Basic Probability Assignment (BPA) values used by D-S is still an open research problem. In this paper, we propose a novel unsupervised methodology to dynamically generate the BPA values, based on both the Gaussian and exponential probability density functions (pdf), the categorical probability mass function (pmf), and the local reachability density (lrd). Then, D-S is used to fuse the BPA values to classify whether the Wi-Fi frame is normal (i.e. non-malicious) or malicious. The proposed methodology provides 100% True Positive Rate (TPR) and 4.23% False Positive Rate (FPR) for the MitM attack, and 100% TPR and 2.44% FPR for the deauthentication attack, which confirm the efficiency of the dynamic BPA generation methodology