Strengthening the Region of Intermediate Support of Continuous Reinforced High-Strength Concrete Slabs with New Cement

Concrete is being widely used as a construction material, hence it is necessary to improve its properties. These days supplementary cementecious materials are used for enhancement of concrete properties. Use of Nano materials is gaining importance due to its vital characteristics, these materials help in developing high performance concrete (Zhang Zenan, et al 2006).In this paper, the use of steel fibers instead of the reinforcement steel bars in the continuous nano-high strength concrete (NHSC) slab panel was experimentally investigated. Tests were carried out on three two-span slab panels under mid span point loads and simply supported at the panels end. The first slab was reinforced by steel bars to resist the negative moments near the internal supports while the other two slab panels were reinforced by steel fibers only of percentage of volume fraction (1 and 2.0) in this zone, without negative steel bars. 5% nano-SiO2 (NS) and 15% of silica fume (SF) contents were used. The load-deflection relationship for the tested slab spans is determined, the first crack load, failure load and deflections were recorded. Also a comparison between the results obtained from this study and that obtained from other study of two continuous slabs made of self compacted concrete (SCC) was made , one of these slabs was reinforced by steel bars near the interior supports and the other is reinforced by steel fibers of (1% and 2%) in this zone. Experimental results show that the ultimate load capacity are increased (15.4% - 32.9%) and the cracking loads are increased (40%-56%) for tested specimens strengthened with SFRC, in comparison with the reference specimens. The comparison between the NHSC slabs and corresponding SCC slabs shows a similar load-deflection curve but the ultimate strength capacity for the NHSC slabs with steel fiber gives ultimate strength larger than SCC  slabs with steel fibers, while the NHSC slabs reinforced by steel bars which show an important effect on the first cracking loading in comparison with SCC slabs. loading in comparison with CC slabs. Keywords: key words, Nano, negative moment, Self-Compacting Concret

Exploring foreign language anxiety in Saudi Arabia : a study of female English as foreign language college students

The goal of the research presented in this thesis is to increase understanding of the\ud experiences (e.g., affective experience, challenges) of female Saudi Arabian students\ud learning a foreign language. To better understand why some language learners have\ud more difficulty acquiring a target language, there has been an increase in research into\ud relationships between foreign language acquisition and affective variables (see Gardner,\ud 1997). However, the vast majority of previous research has been conducted in the West,\ud leaving a gap in understanding other perspectives. The present research uses a case study\ud design, drawing on multiple sources of information to inform an understanding of female\ud students' experience in a private college's English as a Foreign Language (EFL)\ud program. A combination of factors — the importance of learning English, changes in the\ud educational system, and conservative culture — create a unique environment for\ud researching anxiety related to studying EFL. To gain insight into the learners'\ud perspectives, questionnaires, individual and group interviews, and informal classroom\ud observations were used.\ud Ten participants, five from the beginning level (Level 1) and five from a more advanced\ud level (Level 3) of the college English program, were examined. Each participant's\ud experiences are discussed individually, then compared and analysed in the context of\ud existing research literature. All case study participants indicated that they experienced\ud anxiety through responses to a questionnaire, discussion in interviews, and observed\ud behaviours (e.g., avoiding in-class participation).\ud Although some factors, such as teacher-student interactions and teacher behaviour,\ud appeared nearly universally anxiety-provoking among all participants, others factors\ud varied between participants in Levels 1 and 3. These differences and similarities are\ud examined. Finally, implications and limitations, along with suggested recommendations\ud for EFL teachers and policy makers in Saudi Arabia, are discussed

Replacing Reinforcing Steel Bars of Continuous Self-Compacting Concrete Slabs with Steel Fibers at Intermediate Support

In this paper, the use of  steel fibers instead of the reinforcement steel bars in the continuous self compacted concrete slab panel was experimentally investigated. Tests were carried out on three two-span slab panels under mid span point loads and simply supported at the panels end. The first slab was reinforced by steel bars to resist the negative moments near the internal  supports while the other two slab panels were reinforced by steel fibers only of  percentage of volume fraction (0.5and 1.0) in this zone, without negative steel bars. The load-deflection relationship for the tested slab spans is determined, the first crack load, failure load and deflections were recorded. Also a comparison between the results obtained from this study and that obtained from other study of two continuous slabs made of normal strength concrete (CC) was made , one of these slabs was reinforced by steel bars near the interior supports and the other is reinforced by steel fibers of (1%) in this zone. The test results show that the use of steel fibers instead of the steel bars in the negative moment zone with steel fiber ratio of (VF=1%)  increases the ultimate strength by (39%) and small deflection values at the first loading up to (15kN) while if the steel fiber ratio (VF =0.5%) increases the ultimate capacity by (11.7%) The comparison between the SCC slabs and corresponding CC slabs shows a similar load-deflection curve but the ultimate strength capacity for the SCC slabs with steel fiber gives ultimate strength larger than CC  slabs with steel fibers, while the SCC slabs reinforced by steel bars which show an important effect on the first cracking loading in comparison with CC slabs

Experimental and Finite Element Analysis of Continuous RC Slab Panels with Steel Fiber Reinforced Concrete (SFRC) as an Alternative to Negative Reinforcement

This paper presents experimental and finite element analysis of RC slab panels with steel fiber reinforced concrete (SFRC). For this purpose, four SFRC slab panels with (2000×250×50mm) dimensions are poured using a concrete class of (f'c=22MPa) with (15kg/m3) dosage of steel fibers and steel class (fy=410MPa) without shear stirrups. Two of the slab panels were modeled by using nonlinear material properties adopted from experimental study and analyzed till the ultimate failure by ANSYS (Version-15) software. The tested slab panels are subjected to bending by two-point loading, exactly after having been moist-cured for (28 days). The slab panels were tested up to the failure with control of loads. The applied loads and mid-span deflections are carefully recorded at every (5kN) load increment from the beginning till the ultimate failure. The results obtained from the finite element and experimental analyses are compared to each other. It is seen from the results that the finite element failure behavior indicates a good agreement with the experimental failure behavior. The paper concludes that the traditional negative steel reinforcement (steel bars) can be replaced (partially or totally) by using the adopted technique and the contribution of SFRC in manufacturing of thin slabs panels was enhanced. Keywords: Finite Element, Steel fiber, Continuous Slab, Concrete, NSC, Ansys. DOI: 10.7176/CER/11-3-01 Publication date: April 30th 201

Quality assurance of independent work of undergraduates: technological approach

The article reveals an effective way to stimulate learning motivation and activation of cognitive independence of the future masters of teacher educationВ статье раскрывается эффективный способ стимулирования учебной мотивации и активизации познавательной самостоятельности будущих магистров педагогического образовани

Schizophrenia-associated methylomic variation: molecular signatures of disease and polygenic risk burden across multiple brain regions

Genetic association studies provide evidence for a substantial polygenic component to schizophrenia, although the neurobiological mechanisms underlying the disorder remain largely undefined. Building on recent studies supporting a role for developmentally regulated epigenetic variation in the molecular aetiology of schizophrenia, this study aimed to identify epigenetic variation associated with both a diagnosis of schizophrenia and elevated polygenic risk burden for the disease across multiple brain regions. Genome-wide DNA methylation was quantified in 262 post-mortem brain samples, represent- ing tissue from four brain regions (prefrontal cortex, striatum, hippocampus and cerebellum) from 41 schizophrenia patients and 47 controls. We identified multiple disease-associated and polygenic risk score-associated differentially methylated posi- tions and regions, which are not enriched in genomic regions identified in genetic studies of schizophrenia and do not reflect direct genetic effects on DNA methylation. Our study represents the first analysis of epigenetic variation associated with schizophrenia across multiple brain regions and highlights the utility of polygenic risk scores for identifying molecular path- ways associated with aetiological variation in complex disease

Methyl- and acetyltransferases are stable epigenetic markers postmortem

Postmortem brain tissue has been reported to be suitable to delineate regional pattern of possible disturbances underlying epigenetic functionality. However, from many parameters that have been detected in postmortem brain regions it is noteworthy that an effect of postmortem interval (PMI), storage time and premortem parameters should not be underestimated. Our previous investigation revealed that tryptophan (TRP) levels in postmortem brain tissue is affected by PMI and storage time. Since, alteration in TRP levels are assumed to be due to protein degradation, we further investigated whether TRP correlates to variables such as RNA, proteins and DNA modulators. In addition, we aimed to elucidate whether established postmortem variables may influence epigenetic parameters. These were investigated in well characterized postmortem human brain tissue originating from the European Brain Bank consortium II (BNEII). We could confirm previous findings, in which some protein levels alter because of prolonged PMI. Similarly, we demonstrated an influence of increased storage period on TRP levels, which might indicate degradation of proteins. Still not all proteins degrade in a similar manner, therefore a specific analysis for the protein of interest would be recommended. We found that methyltransferase- and acetyltransferase-activities were relatively preserved with PMI and storage duration. In conclusion, preservation of acetyltransferase- and methyltransferase-activities provides possible evidence of stability for epigenetic studies using postmortem tissu

Measurement of K-S(0) and K*(0) in p plus p, d plus Au, and Cu plus Cu collisions at root s(NN)=200 GeV

The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K-S(0) and K*(0) meson production at midrapidity in p + p, d + Au, and Cu + Cu collisions at root s(NN) = 200 GeV. The K-S(0) and K*(0) mesons are reconstructed via their K-S(0) -\u3e pi(0)(-\u3e gamma gamma) pi(0)(-\u3e gamma gamma) and K*(0) -\u3e K-+/-pi(-/+) decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K-S(0) and K*(0) mesons in d + Au and Cu + Cu collisions at different centralities. In the d + Au collisions, the nuclear modification factor of K-S(0) and K*(0) mesons is almost constant as a function of transverse momentum and is consistent with unity, showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu + Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p + p yield scaled by the number of binary nucleon-nucleon collisions in the Cu + Cu system. In the p(T) range 2-5 GeV/c, the strange mesons (K-S(0), K*(0)) similarly to the phi meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (pi(0)) and the nonsuppressed baryons (p, (p) over bar). At higher transverse momentum, p(T) \u3e 5 GeV/c, production of all particles is similarly suppressed by a factor of approximate to 2

Repatriation-returning home and adjusting : A qualitative study of the repatriation process in three Swedish multinational corporations

In order to stay competitive in the market, multinational corporations (MNC) need to expand their businesses in the international market. Sending employees to work abroad is a great way of expanding. However, having employees working abroad, brings a lot of advantages for the corporation, but it can also be a disadvantage for the corporation if the final step of international assignments, which is the repatriation process, has not been handled correctly. This thesis investigates how the managers of IKEA, Electrolux and SEB handle the repatriation process and how the repatriates experienced the process, during their pre-return period and post-return period. Our findings show that the repatriates experienced that the repatriation process was poorly conducted by the corporations due to lack of engagement from their side. On the other hand, managers of the companies felt that they handled the repatriation process very well. Therefore, it is essential that corporations prepare the employees well, before they start the international assignments, as well as help them to readjusting back in the home country. Working with practical expectations may lead to a smooth adjustment, which in turn, leads to a well-functioning repatriation process