Mechanical properties of soft clay stabilized with cement-rice husks (RH)

Chemical stabilization has been extensively used for the improvement of soft clay soils, in enhancing the shear strength and limiting the deformation behaviours. Cement is widely used as a stabilizing material for soils, but the increasing price is causing economic concerns among practitioners and clients alike. The quest for alternative cheaper stabilizing agents is therefore more urgent than before. Rice husk is a major agricultural waste in Malaysia and the common disposal method of open burning has notoriously contributed to environmental pollution. The possibility of admixing rice husks with cement for stabilizing soft soils could be a solution to both problems. This study was aimed at assessing the usefulness of cement-rice husks as an effective soil stabilizer for improving the mechanical properties of clay soils. Laboratory experiments were carried out on a stabilized soft clay to study the inter-relationships between shear wave velocity, one-dimensional compressibility and unconfined compressive strength. Bulk clay samples were collected from the Research Centre for Soft Soils (RECESS) of UTHM. The stabilized specimens were prepared with the clay admixed with 5 % and 10 % cement and various quantities of rice husks, then compacted into cylindrical specimens measuring 38 mm in diameter and 76 mm high. The specimens were then left to cure for different periods up to a month. The stabilized specimens were observed to undergo increase in stiffness and strength, as well as significant reduction in compressibility, highlighting the great potential of cement-rice husk as an alternative soft soil stabilizer. Keywords: Clay soil stabilization, cement, rice husk, shear wave velocity, onedimensional compressibility, unconfined compressive strengt

Shear strength analysis of concrete beams reinforced with GFRP bars using strut and tie model

This dissertation presents an experimental investigation on the behavior and ultimate shear strength of reinforced concrete beam. Sixteen reinforced concrete beams was design and tested to failure. This study consists of two series of beams, which are conventional steel reinforced beams (BSN) and reinforced concrete beams with Strut and Tie Model (STM) using StaadPro software and both result were compared in term of shear strength. The main test variables were shear span-to-depth ratio (2.1 and 2.9), percent of longitudinal reinforcement ratio (tension) steel and GFRP (0.6% and 0.9%), and shear reinforcement ratio (1.5% and 0.6%). The test results revealed that the mode of failure for all beam is flexural with shear reinforcement characteristics and longitudinal reinforcement ratio play a critical role in controlling the mode of failure. The experimental approved that the spacing between shear cracks for the specimens with larger shear span to depth ratio is greater than the smaller shear span to depth ratio and while the shear span to depth ratio (a/d) decreases, the shear strength increase. For longitudinal reinforcement ratio it can be inferred that the higher longitudinal reinforcement ratio brings the smaller diagonal crack. Also, greater stirrup spacing leads to the greater diagonal crack, confirming that there is a significant influence of the stirrup spacing on the spacing between shear cracks. The reason for this behavior is the decreasing effective concrete area, in which shear crack width is controlled by the stirrup, and hence the increasing bond effect between the stirrup and the surrounding concrete

Pembangunan dan penilaian modul berbantukan komputer bagi subjek pemasaran : Politeknik Port Dickson

Kajian ini bertujuan membangunkan Modul Berbantukan Komputer (MBK) bagi subjek Pemasaran. MBK ini dibangunkan dengan menggunakan pensian AutoPlay Media dan Flash MX. Sampel kajian ini terdiri daripada 30 orang pelajar Diploma Pemasaran di Politeknik Port Dickson. Data dikumpulkan melalui kaedah soal selidik dan dianalisis berdasarkan kekerpan, peratusan dan skor min dengan menggunakan perisian Statistical Package For Social Sciene (SPSS) versi 11.0. Dapatan kajian menunjukkan penilaian terhadap pembagunan MBK di dalam proses P&P adalah tinggi. Ini bermakna MBK ini sesuai digunakan di Politeknik Port Dickson di dalam proses P&P

Optimization of stand-alone photovoltaic system by implementing fuzzy logic MPPT controller

A photovoltaic (PV) generator is a nonlinear device having insolation-dependent volt-ampere characteristics. Since the maximum-power point varies with solar insolation, it is difficult to achieve an optimum matching that is valid for all insolation levels. Thus, Maximum power point tracking (MPPT) plays an important roles in photovoltaic (PV) power systems because it maximize the power output from a PV system for a given set of condition, and therefore maximize their array efficiency. This project presents a maximum power point tracker (MPPT) using Fuzzy Logic theory for a PV system. The work is focused on a comparative study between most conventional controller namely Perturb and Observe (P&O) algorithm and is compared to a design fuzzy logic controller (FLC). The introduction of fuzzy controller has given very good performance on whatever the parametric variation of the system

Investigating the properties of bio-chemical networks of artificial organisms with opposing behaviours

Organisms, be it singled-celled organisms or multi-cellular organisms, are constantly faced with opposing objectives requiring different sets of behaviours. These behaviours can be classified into two, predatory behaviours or anti-prey behaviours, with one set of behaviours causing an opposite effect to the other. A healthy organism aims to achieve its equilibrium state or to be in homeostasis. Homeostasis is achieved when a balance between the two opposing behaviours is created and maintained. This raises some questions: is there an innate mechanism that encodes for these categories of behaviours? Is there also an innate mechanism(s) that resolves conflicts and allows switching between these two opposing behaviours? If we consider artificial organisms as single-celled organisms, how do the organisms’ gene regulatory network, metabolic network and/or signalling network (their biochemical networks) maintain homeostasis of the organisms? This paper investigates the properties of the networks of best evolved artificial organisms, in order to help answer these questions, and guide the evolutionary development of controllers for artificial systems

Clark County School District’s English Language Learners An Analysis of Enrollment, Educational Opportunities, and Outcomes in Nevada and CCSD

As the largest school district in Nevada and the fifth-largest school district in the country, Clark County School District (CCSD) served approximately 310,000 students in 341 schools during the 2010-2011 school year. Typical of urban districts, more than half of its students are eligible for free or reduced-price lunch, and 68 percent are students of color. Many schools are located in neighborhoods of concentrated poverty, as well as racial and linguistic isolation (Terriquez, Flashman & Schuler-Brown 2009). Also, the patterns of enrollment show dramatic increases in the proportions of English language learners (ELLs) in CCSD over the last two decades

Extended Klein-Gordon Action, Gravity and Non-Relativistic Fluid

We consider a scalar field action for which the Lagrangian density is a power of the massless Klein-Gordon Lagrangian. The coupling of gravity to this matter action is considered. In this case, we show the existence of nontrivial scalar field configurations with vanishing energy-momentum tensor on any static, spherically symmetric vacuum solutions of the Einstein equations. These configurations in spite of being coupled to gravity do not affect the curvature of spacetime. The properties of this particular matter action are also analyzed. For a particular value of the exponent, the extended Klein-Gordon action is shown to exhibit a conformal invariance without requiring the introduction of a nonminimal coupling. We also establish a correspondence between this action and a non-relativistic isentropic fluid in one fewer dimension. This fluid can be identified with the (generalized) Chaplygin gas for a particular value of the power. It is also shown that the non-relativistic fluid admits, apart from the Galileo symmetry, an additional symmetry whose action is a rescaling of the time.Comment: 7 pages, two columns. Minor change