THE INFLUENCE OF TENSION STIFFNENING MODELS ON THE DYNAMIC ANALYSIS OF REINFORCED CONCRETE SLABS

In the present work, the finite element method has been used to investigate the behavior of reinforced concrete slabs subjected to dynamic loads. Eight-node Serendipity degenerated elements have been employed. This element is based on isoperimetric principles with modifications, which relax excessive constraints. The modifications include reduced order integration to overcome the shear locking.A layered approach is adopted to discretize the concrete through the thickness. Both an elastic-perfectly plastic and strain hardening plasticity approaches have been employed to model the compressive behavior of the concrete. A tensile strength criterion is used to initiation of crack and a smeared fixed crack approach is used to model the behavior of the cracked concrete. Five models are used to consider the effect of tension stiffening in the cracked concrete.Implicit Newmark with corrector-predictor algorithm is employed for time integration of the equation of motion.Several examples are analyzed using the proposed model. The numerical results showed good agreement with other sources

Experimental and Numerical Analysis of Piled Raft Foundation Embedded within Partially Saturated Soil

This paper presents an experimental and numerical study to investigate the load carrying capacity of piled raft foundation embedded within partially saturated sandy soil. The effect of matric suction on the bearing capacity of the foundation system was investigated. The experimental work consists of two models of foundation, circular raft foundation and circular piled raft foundation. The circular raft foundation has dimensions of 10cm in diameter, and 2.5cm thickness, while the piled raft foundation has the same dimensions of the circular raft model but with a single pile of 2.0cm in diameter and 40.0cm in length fixed at the center of the raft. Both models are loaded and tested under both fully saturated condition and unsaturated conditions, which are achieved by, predetermined lowering of water table. The lowering of water table below the soil surface was achieved in to two different depths to get different values of matric suction and the relationship between matric suction and depth of ground water table was measured in suction profile set by using three Tensiometers (IRROMETER). The soil water characteristic curve (SWCC) estimated by applying fitting methods through the software (SoilVision). A validation process then was carried out for the case of circular piled raft foundation with lowering the water table 45cm bellow soil surface in the aid of a sufficient finite element computer program ABAQUS 6.12. An eight-node axisymmetric quadrilateral element CAX8RP and CAX8R were used to simulate the soil continuum and piled raft respectively. The interaction method used to simulate the intersect surfaces of the system (pile-raft-soil) is a surface-to-surface discretization method under the concept of master and slave theory. The behavior of piled raft material is simulated by using a linear elastic model while the behavior of soil is simulated by an elasto-plastic model by the use of the Mohr-Coulomb failure criterion. The results of the experimental work demonstrate that the matric suction has a significant role on the bearing capacity of all tested models. It shows that the ultimate bearing capacity of circular raft foundation under a partially saturated condition is increases by about (7.0-8.0) times than the ultimate bearing capacity of fully saturated condition when lowering the water table 45 cm below the soil surface. While the ultimate bearing of circular piled raft foundation under partially saturated condition increases by about (8.0-9.0) times than the ultimate bearing capacity of fully saturated condition when lowering the water table 45 cm below the soil surface. The results of the ultimate bearing capacity of piled raft foundation that obtained from the experimental model and from the numerical modelling for the same soil condition and same matric suction indicate that a successful validation is achieved for the simulation process

Evaluation of different strategies for induction of chilling tolerance in spring maize using moringa leaf extracts

Spring maize is highly sensitive to low temperatures during the early development of seedlings and to high temperatures during its reproductive stage. Different strategies are being used to minimize the adverse effects of temperature extremes. Therefore, a field experiment was conducted to enhance the performance of spring hybrid maize by seed priming (3% MLE) and transplanting 20 and 30-day-old seedlings. Seed priming with moringa leaf extract (MLE) significantly enhanced stand establishment in both direct sowing and in transplanting, as indicated by the higher emergence percentage, emergence index, and lower time taken to start of emergence and mean emergence time. Minimum days from sowing to tasseling and silking were found in MLE primed 20-day-old seedlings grown in a nursery. However, all the agronomic parameters increased considerably with MLE priming of 20-day-old seedlings. Thus, MLE priming reduced chilling damage by improving stand establishment, whereas transplanting 20-day-old seedlings further enhanced the agronomic traits, yield, and quality of maize. However, the performance of maize plants from 30-day-old transplanted seedling and direct sowing was substandard

Correlations between serum hdyrogen peroxide level, oxidative damage indices and biochemical markers in end stage renal disease patients

Introduction: Hydrogen peroxide is an important intermediate ofendogenous free radical activity which could lead to the generation of more potent free radicals that cause macromolecular damage. An imbalance between the excessive generation of pro-oxidant(free radicals) and insufficient antioxidant defence leads to oxidative stress and this event is marked in end stage renal disease (ESRD) patients. The objective of this study is to assess the correlation between serum hydrogen peroxide level and oxidative damage indices as well as several biochemical markers in ESRD patients. Methods: Fasting blood samples were collected from patients (n=106) attending the University Malaya Medical Centre, Kuala Lumpur. The control subjects mainly comprised healthy blood donors with no known clinical/biochemical abnormality. The serum and plasrna were separated and the levels of hydrogen peroxide, oxidative damage indices (pentosidine, advanced oxidation protein products, malonaldehyde) and biochemical parameters (albumin, creatinine, fenitin, triglyceride, low density lipoproteins and total cholesterol) were estimated according to established rnethods. Results: Levels of hydrogen peroxide and the oxidative damage indices were significantly higher in the patients compared to healthy subjects. A strong positive correlation was present between hydrogen peroxide and the oxidative indices(r>0.80, p<0.001). Hydrogen peroxide was positively (weak) associated with the biochemical parameters except for albumin levels which showed a negative correlation with hydrogen peroxide levels in these patients (r: -0.40, p< 0.01). Conclusion: Serum hydrogen peroxide strongly correlates with oxidative damage indices and could serve as an additional marker of oxidative stress in end stage renal disease

Process Parameter Optimization of a Polymer Derived CeramicCoatings for Producing Ultra-High Gas Barrier

YesSilica is one of the most efficient gas barrier materials, and hence is widely used as anencapsulating material for electronic devices. In general, the processing of silica is carried out at hightemperatures, i.e., around 1000◦C. Recently, processing of silica has been carried out from a polymercalled Perhydropolysilazane (PHPS). The PHPS reacts with environmental moisture or oxygen andyields pure silica. This material has attracted many researchers and has been widely used in manyapplications such as encapsulation of organic light-emitting diodes (OLED) displays, semiconductorindustries, and organic solar cells. In this paper, we have demonstrated the process optimization ofthe conversion of the PHPS into silica in terms of curing methods as well as curing the environment.Various curing methods including exposure to dry heat, damp heat, deep UV, and their combinationunder different environments were used to cure PHPS. FTIR analysis suggested that the quickestconversion method is the irradiation of PHPS with deep UV and simultaneous heating at 100◦C.Curing with this method yields a water permeation rate of 10−3g/(m2·day) and oxygen permeationrate of less than 10−1cm3/(m2·day·bar). Rapid curing at low-temperature processing along withbarrier properties makes PHPS an ideal encapsulating material for organic solar cell devices and avariety of similar applications.King Saud Universit

Evaluating the potential effect of seed priming techniques in improving germination and root shoot length of maize seed

The present research was conducted under laboratory conditions. The purpose of research was to investigate the potential of priming with press mud, peat moss, sand, gunny bags, compost, farm yard manure and moringa leaf extract (MLE) on seedling growth and germination capacity of maize seed. Untreated or non-primed seeds were used as a control treatment. Priming treatments improved germination capacity, stand establishment and seedling vigor, compared with control. Priming with moringa leaf extract enhance germination and seedling vigor of maize seed, compared with the control and other seed primed treatments. In moringa leaf extract primed seeds, root and shoot growth was improved. Overall, moringa leaf extract primed maize seeds performed better than all other treatments and it could be related by seedling vigor enhancement and lowering the mean germination time, due to imbibition of higher quantity of water and earlier enzymatic activity. The results propose that moringa leaf extract priming treatment had the potential to enhance germination, stand establishment and early growth of maize seeds

Quantum phase properties of two-mode Jaynes-Cummings model for Schr\"odinger-cat states: interference and entanglement

In this paper we investigate the quantum phase properties for the coherent superposition states (Schr\"odinger-cat states) for two-mode multiphoton Jaynes-Cummings model in the framework of the Pegg-Barnett formalism. We also demonstrate the behavior of the Wigner ($W$) function at the phase space origin. We obtain many interesting results such as there is a clear relationship between the revival-collapse phenomenon occurring in the atomic inversion (as well as in the evolution of the $W$ function) and the behavior of the phase distribution of both the single-mode and two-mode cases. Furthermore, we find that the phase variances of the single-mode case can exhibit revival-collapse phenomenon about the long-time behavior. We show that such behavior occurs for interaction time several times smaller than that of the single-mode Jaynes-Cummings model.Comment: 23, 8 figure

Feasibility study of rainbow trout (Oncorhynchus mykiss ) culture in brackish water in earthen fish pond in North Khorasan province

The use correct of non-agricultural land due to saline and waternon fresh for rearing of aquatic animals, especially fish, in good seasons, can generate for employment and provide fertile ground . This study aimed to assess the ability of Rainbow Trout reared in earthen ponds potential using brackish water stub area south of North Khorasan province in cold seasons (autumn and winter) have been conducted. Farming operations in three earthen ponds, each with an area of 3,000 square meters and two water wells within 160 days of the initial electric Bahdayt 8400 and 18100 µs was conducted. Average initial weight of juveniles when introduced into soil ponds 32.0±1.0 and 22.7±1/7 grams and density drop in the of ponds 5 and 7 number per cubic meters . Feeding on pond done recipes nutrition standards Related to fish size and water temperature was during the period culture . To help improve the water quality during the breeding ponds of cyclic change in volume of pond water (20-15%) and two aeration SPLASH with errive fresh water to form rain fall in each pond was used. The results obtained during the period of measurement water physico-chemical parameters (temperature, electrical conductivity, dissolved oxygen, nutrients, total dissolved substances, acidity) shows changes in the mean amplitude of these factors has been tolerated for raising trout The results showed that children reared trout have been introduced since the introduction of nteroperability with brackish water in the pond also grown to over 14 thousand have salt and water changes physical and chemical factors have endured. The results showed that fish farming in addition to works by adapting the environment had to foster the growth of the pond water . So in 5 months, with a mean survival of 87 percent hindrance develop marketable size with an average weight of 340±12-390±13and 470 ±17grams and have a total production of more than 20 tonnes. All of it has been confirmed, the study area (SFRAIEN)is very suitable for the breeding Rainbow trout of pond during the fall and winter seasons