Variation of safety factor with suctions of infinite clay slope under partially saturated condition

Anuchit Uchaipichat

In this paper, the simulation results of variation of safety factor with suctions of infinite clay slope under partially saturated condition are presented. The variations of safety factor with matric suction ranging from 1 to 100, 000 kPa are presented. The undrained shear strength, which is a function of matric suction, is back-calculated from the laboratory bearing tests reported by Uchaipichat and Man-koksung (2011). The simulations results show that the safety factor increases with increasing matric suction for all values of slope thickness. The results also show a decrease in safety factor with increasing values of slope thickness.

Experimental and theoretical design for a new array micro-lenses silicon solar cell concentrator

Ali H. Al-Hamdani

In this paper, a new model for array of micro-lenses concentrator was designed. This concentrator consists of array of micro-lenses (MLA) to focus solar light on four rectangular slaps of photovoltaic Si solar cell. The design aim to reduce the cost of the concentrators by reduces the effective area of the high cost silicon material area and simplified the structure of the system. The solar cell with the MLA- concentrator adds energy conversion efficiency (11.98%) and reducing the total cost.

Power aware routing in mobile ad hoc networks: a survey

Power consumption is a crucial design concern in Wireless ad hoc networks since wireless nodes are typically battery limited. Power consumption can occur due to receiving the data, transmitting the data traffic, mobility etc. Power failure of mobile node not only affects the node itself but also its ability to forward packets on behalf of others and hence overall network lifetime. It might not be possible to replace/recharge a mobile node that is powered by batteries. To take full advantage of life time of nodes, traffic should be routed in a way that power consumption is minimized. Power Aware Routing is a consideration in a way that it minimizes the energy consumption while routing the traffic, aims at minimizing the total power consumption of all the nodes in the network, minimizing the overhead etc and thus, at maximizing the lifespan of the network using some Power Aware Routing Protocols. Although establishing correct and efficient routes is an important design issue in mobile ad hoc networks (MANETs), a more challenging goal is to provide power efficient routes because mobile nodes operation time is the most critical limiting factor. This paper surveys and classifies the power aware routing protocols proposed for MANETs. They minimize either the active communication energy required to transmit or receive packets or the inactive energy consumed when a mobile node stays idle but listens to the wireless medium for any possible communication requests from other nodes. Transmission power control, load distribution and power management approaches are used to minimize active communication energy while sleep/power-down mode approach is used to minimize inactive communication energy using some power aware metrics like energy consumed per packet, time to network partition, variance in node power levels, cost per packet, throughput, end-to-end delay, packet delivery ratio etc. Each protocol has definite advantages/disadvantages and is well suited for certain situations. The purpose of this paper is to facilitate the research efforts in combining the existing solutions to offer a more power efficient routing mechanism.

Factors effect to the sulfide generation rate in the to lich river, Vietnam

Nguyen Huu Huan, Nguyen Xuan Hai, Tran Yem and Nguyen Nhan Tuan

In this paper, the water quality index (WQI) was used as a indicator to assess the pollution level of the water quality in the To Lich River. The comparison of most important factors on the sulfide generation in the open channel and pipe sewers system was presented. The result also denoted that the close relationship between Oxygen - Redox Potential (ORP) values and log {[S^2-]/ [SO₄^2-]} by correlation coefficient R² = 0.6369. And surface water layer was the main source of To Lich River to produce sulfide by Sulfate Reducing Bacteria (SRB). The factors to affect the sulfide generation rate in the To Lich River (open channel) were organic matter (BOD₅), and environmental conditions such as ORP, pH, and Temperature (T). The found model in this study for estimating the sulfide generation from the To Lich River depended on the variables such as: ORP, T, pH, BOD₅, with the correlation coefficient R² = 0.9619, as follows:

[S^2-] = 0.0063 * ORP + 0.0427 * T - 4.371 * pH - 0.0012 * BOD₅ + 31.87

Flexural strength of fibrous ultra high performance reinforced concrete beams

Wasan I. Khalil and Tayfur Y. R.

Abstract:

The flexural behavior of eleven 150×150×1950 mm ultra high performance conventionally reinforced concrete beams containing hooked and crimped steel fibers with different volume fractions (0.5 %, 0.75 % and 1 %) in full and partial depths of beams cross sections is studied in this investigation. The load deflection relationship, resilience, toughness indices, first crack load, ultimate load and concrete strains were investigated. The experimental results show that the addition of steel fibers slightly enhances the load-deflection relationship and ultimate load for beam specimens. The type of steel fibers (crimped and hooked) has a little effect on load-deflection behavior, ultimate moment capacity, cracking pattern, while in resilience and toughness, beam specimens with hooked steel fiber showed slightly better behavior than those with crimped steel fibers. The ultimate tensile strength of beams has been rederived and contributed in order to calculate the moment capacity. The calculated ultimate moment capacity was in good agreement with the experimental ultimate moment capacity.

Abstract:

In this paper, structural analyses show that the rocks in the North - Eastern part of Gjilani Region represent a mega-antiform reversed towards the south-west. This is accompanied by meso - and micro-isoclinal folds, with reversal towards the West, observed in the tectonic stratification with the thickness of several millimetres to several meters. These tectonic stratifications under green schist`s facies conditions, amphibolites, marbles, quartzes, etc., a result from the tectonic transposition during the deformation phase associated with a regional homogeneous schistosity Sn (Axial plan of isoclinal folds). This last one has NNW strike and dip, once to East and once to West with the angle about 70°. The associated metamorphism is the high grade to middle metamorphism, aged of 150 to 130 million years deducted from dating in neigh boring regions (Most, 2003). The cinematic analyses concerning this deformation phase indicate a transport of the upper part towards the SW. Concerning this phase of deformation, the direction of displacement is deduced from the reversed polarity of the Sn, while transport sense is deduced from the cinematic analysis on field and the microscope analysis. Structural and microstructural analysis show also two successive phases accompanied by a crenulation schistosity  Sn+1 and fracture schistosity S n +2, connected to two deformations stages D n +1 and D n +2. The Age of metamorphism that accompanies these two stages is difficult to assess. The crenulation schistosity has a heterogeneous behaviour and is proving that belongs to the ductile-brittle deformation and depends on the facial lithology. While the fracture schistosity shows a homogeneous behaviour with wide strike with strong dip angle once north, once south.

The provision of safe water, sanitation and hygiene in schools has been established to improve health, boost educational achievement, and promote gender equity which has a positive impact on the society. The aim of this pilot study is to ascertain the state of WASH program in public secondary schools in South-Western Nigeria. A total of twelve schools which span across three Local Government areas in two States (Lagos and Ogun), in South-Western Nigeria were selected. The standard for WASH in schools by UNICEF was used as the guiding principles to evaluate the adequacy of the various WASH components. Out of the 12 public secondary schools visited, only 3 (25%) had drinking water points (boreholes) and 40% of the schools do not have separate latrines for boys and girls, and for promoting privacy of older girls. Only 1 (10%) of the schools had hand washing points but without soap and there is no plan in the schools for advancing WASH program. This study reveals that the present WASH practice in many of the schools is not adequate.

Abstract:

Al6061 MMC’s are quiet popular in engineering applications because of low density and high stiffness. Carbon Nano tube of late, has emerged to be an excellent reinforcement material for aluminium based metal matrix composites. The present work attempts at developing Al6061 based MMC’s using MWCNT’s for reinforcement using powder metallurgy and stir casting techniques. In this study the details of the manufacturing techniques have been discussed. The SEM images and microstructure details from optical microscope are presented for the various compositions of the MMC’s that have been developed. From the SEM images and microstructure of the composites it is observed that there is uniform distribution of MWCNT and good bonding exists between the carbon nano tubes and the matrix, establishing the stir casting technique for production of Al6061-MWCNT metal matrix composites.

Abstract:

The fuzzy controllers were developed to create alternative ways to classic control in order to avoid complex mathematical calculations involved in the design and have the characteristic to adapt itself to changes that may occur in the plant due to external sources. This paper shows the design of a fuzzy PD control for a furnace, which can be initialized to work with different temperature sensors that are commonly found in industry (PT100, J Thermocouple, K thermocouple, S thermocouple). In this paper we discuss the advantages and disadvantages of working with fuzzy control, plus it is orderly explained the different stages of the process to create it, from the signal processing of the sensors to the controller output.

Abstract:

This paper proposed the novel approached toward the heat transfer enhancement of plate and fin heat exchanger using improved fin design facilitating the vortex generation. The vortex generator can be embedded in the plane fin and that too in a low cost with effect the original design and setup of the commonly used heat exchangers. The various design modifications which are implemented and studied numerically and experimentally is been discussed in the paper.