Effect of fly ash and silica fume on compressive strength of self-compacting concrete under different curing conditions

AbstractThis study presents an experimental study on self-compacting concrete (SCC) with two cement content. The work involves three types of mixes, the first consisted of different percentages of fly ash (FA), the second uses different percentages of silica fume (SF), and the third uses a mixture of FA and SF. After each mix preparation, nine cylinder specimens are cast and cured. Three specimens are cured in water for 28days, three specimens are cured in water for 7days, and three specimens are left in air for 28days. The slump and V-funnel test are carried out on the fresh SCC and concrete compressive strength values are determined. The results show that SCC with 15% of SF gives higher values of compressive strength than those with 30% of FA and water cured specimens for 28days give the highest values of compressive strength

Effect of using swimmer bars on the behavior of normal and high strength reinforced concrete beams

AbstractShear failure of RC beams is often sudden and catastrophic. The shear cracks progress rapidly without warning, and the diagonal cracks are considerably wider than the flexural cracks. In this study, two types of shear reinforcement are used, traditional stirrups and swimmer bars. Swimmer bar system is a new type of shear reinforcement defined as inclined bars welded to longitudinal top and bottom bars. High strength concrete is a more brittle material than normal strength concrete, and the cracks that form in high strength concrete will propagate more extensively than in normal strength concrete. Ten beams are tested, and the main variables investigated were two different shapes of swimmer bars in addition to traditional stirrups, number of swimmer bar planes, and compressive strength of concrete. The test results will be presented and discussed in order as deflection, ultimate loads, ultimate shear stress, cracking stress and failure modes. Moreover, shear strain is calculated

Film forming gel for treatment of oral mucositis: In vitro studies

Oral mucositis is one of the main complications of non-surgical cancer treatments. The present work focuses on the treatment or reduction of oral mucositis by using combined mechanism by formation of physical barrier by forming a film to cover the oral ulcer and use of therapeutic agents, such as diclofenac sodium and ofloxacin separately or in combination. The selected polymers for film forming gel formulations are Hydroxypropylcellulose (HPC), hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (Na CMC) and carbopol 940 (CP). The residence time in simulated buccal saliva was between 5.5 to 6 hours for all formulations. The in-vitro release data of the investigated drugs from the prepared formulations followed zero-order and diffusion mechanism. The permeability studies data revealed that diclofenac sodium showed higher permeability from Na CMC/CP (2:0.3%) than from HPMC 4%, while in case of ofloxacin higher permeability was shown from Na CMC/CP (2:0.3%) than from HPMC/HPC (2:3%). The permeation parameters for diclofenac sodium and ofloxacin in their combination do not depend on either viscosity or pH, they depend on the type of polymers used.Keywords: Mucositis; Film-forming gel; Rheology; In vitro studies

Measuring the Impact of Service Quality Dimensions and Product Quality on Customer Satisfaction: The Case of Retail Market in Egypt

Customer satisfaction importance is increasing, as it is a key factor in any business success story. Retailers are very careful regarding the customer satisfaction factor, as it is a key determinant in customer’s decision whether to continue or discontinue their association with the retailer. In the recent years, the number and size of retailers in Egypt increased due to the swift growth in Egyptian population. Foreign hypermarkets such as Spinneys, Carrefour, Lulu, Makro, Panda,etc.have created a severe competition with the local modern hypermarkets and traditional markets. Retailers need for a reliable measure or model to test their service quality and product quality and their impact on customer satisfaction to ensure asustainable competitive advantage. Therefore, theaim of this researchisto measure the impact of service quality dimensions (physical aspects, reliability, personal interaction, policy, and problem solving) and product quality on customer satisfaction in the hypermarket sector in Alexandria, Egypt. In order to achievethis aim, a questionnaire has been created and distributed over a sample of 450 respondents to hypermarket buyers in Alexandria, Egypt. 390 questionnaires were collected with 86.7% response rate from the participants and were analysed by using the SPSS. The results of this research showed that there is a significant positive impact offive variables (physical aspects, personal interaction, policy, problem solving, and product quality) on customer satisfaction. Particularly, the hypermarket policy has the strongest impact on customer satisfaction in hypermarket sector followed by personal interaction, product quality, and physical aspects, where problem-solving factor has the least effect on customer satisfaction. Keywords: Service quality dimensions, product quality, retail market, hypermarket sector, customer satisfaction, Egyp

Histological effect of ovariectomy and estrogen replacement on parotid gland of adult albino rat

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Use of Phenols, Peroxidase and Polyphenoloxidase of Seed to Quantify Resistance of Cotton Genotypes to Damping-off Incited by Fusarium oxysporum

A greenhouse test was conducted in 2011 and 2012 growing seasons at Giza Agricultural Research Station to evaluate the reaction of six cotton genotypes to damping-off incited by Fusarium oxysporum. Damping-off incidence on the genotypes ranged from 70-88%. In general, the genotypes could be divided into highly susceptible, susceptible, and moderately susceptible. Data for damping-off incidence and level or activity of some biochemical components (phenols, peroxidase, and polyphenoloxidase) were entered into a computerized linear regression analysis. The analysis contrasted seven predictive models by using the biochemical components, singly or in combination, as biochemical predictors. It was evident that models nos. 2 and 6 were the best models for predicting incidence of damping-off. The superiority of these models was attributed to their high RІ values (0.748 and 0.902, respectively) and the significance of their F. values (P = 0.026 and P = 0.031, respectively). The results of the present study suggest that peroxidase alone or both peroxidase and polyphenoloxidase, which may or may not parts of damping-off resistance mechanisms, can be used as biochemical markers to predict resistance to damping-off incited by F. oxysporum

Flexural Behavior of Lightweight Composite Ferrocement Plates

In recent years, producing lightweight structures is considered as one of the most important application of concrete. It has extensive applications in the architect and insulation work. The main objective of this study is to investigate the behavior and the performance of lightweight ferrocement (LWF) composite plates with lightweight materials as filler materials in flexural. Fifteen lightweight ferrocement (LWF) composite plates were investigated by conducting flexural tests. The main variables are (the thickness of plates, the type of filler materials, the type and number of layers of meshes). The behavior of lightweight ferrocement (LWF) composite plates is investigated by conducting flexural tests on fifteen simply supported rectangular plates under three lines loadings. Fifteen plates represented in twelve lightweight ferrocement (LWF) plates and three conventional reinforced concrete (RC) plates. The ferrocement plates were divided into three groups according to the thickness of plates 6cm, 8cm and 10cm. The structural performances of the LWF and RC plates are investigated in terms of crack load, load-deflection curves, stiffness, energy absorption capacity, ductility index, ultimate flexural load-to-weight ratio, load-strain curves, crack patterns, and the failure modes. The test results revealed remarkable enhancement in the flexural behavior and potential application of lightweight ferrocement (LWF) composite plates to produce lightweight structural elements as compared to that of the reinforced concrete (RC) plates, which lead towards the industrialization of building system and meets with innovation and expansible application of concrete construction technology results in better efficiency of developing of lightweight composite ferrocement plates

NDM-559: EXPERIMENTAL INVESTIGATION OF TWO-WAY CONCRETE PANELS EXPOSED TO IMPACT LOAD

Protecting existing and new structures from potential terrorist attacks and accidents is becoming an essential consideration in the design of most structures. Building façade is the first layer exposed to external loading, thus it acts as the first line of defence against external loads. Precast concrete panels are mostly used in external building\u27s façade for modern construction, and therefore their resistance to other dynamic loads such as impact load needs further evaluation. This paper presents the results of an experimental research on two-way reinforced concrete panels as well as thin ferrocement concrete panels under impact loading. The impact test apparatus used is versatile enough to test large variety of specimens modeling façade units. The performance of the panels under impact load is evaluated in terms of: the failure mode; the maximum impact loads sustained by the panels; the number of impact loads up to failure; the maximum load transmitted to the supporting frame; and the strain induced in the panels. The effect of the different design parameters including the reinforcement amount, spacing and location across the panel thickness on the dynamic response of the panel to impact load are considered. Results clearly showed the significant effect of reinforcement on the overall resistance to impact loading. This research outcomes provide a better understanding of the performance of concrete panels under impact loading that can help enhancing structural design under such loads