Teachers' Beliefs And Levels Of Use In The Adoption Of The Student-Active Learning Approach In EFL Classrooms In Oman

The main purpose of the study was to investigate the teachers' Beliefs and their Levels of Use (LoU) in the adoption of the Student-Active Learning (SAL) approach in their English as a Foreign Language (EFL) classrooms in Oman. It was also aimed to investigate the challenges encountered by the teachers in the adoption of the SAL approach. Matlamat utama kajian ini adalah menyelidik kepercayaan guru dan Tahap Penggunaan (TP) kaedah Pemelajaran Aktif-Pelajar (PAP) di bilik darjah EFL di Oman. Kajian ini juga turut menyelidik cabaran yang dihadapi oleh para guru dalam merealisasikan kaedah PAP

GROUND STATES AND GIBBS MEASURES OF λ-MODEL ON CAYLEY TREE OF ORDER TWO

Abstract Statistical mechanics deals with the average properties of a mechanical system. Some examples are; the water in a kettle, the atmosphere inside a room and the number of atoms in a magnet bar. These kinds of systems are made up of a large number of components, usually molecules. The observer has restricted power to consider all the components. All that can be done is to specify a few average quantities of the system such as its density, pressure or temperature. The main objective of statistical mechanics is to predict the relationship between the observable macroscopic properties of the system, given only a knowledge of the microscopic interactions between the components. The present thesis is devoted to a model whose interacting molecules are located on nearest neighbor vertices of a Cayley tree. In this thesis, ground states and Gibbs measures of λ-model on a Cayley tree of order two are investigated. This investigation is closely related to the phase transitions phenomenon for lattice models on trees, by considering the model where spin has only three values. This kind of model aims to describe all its ground states and study phase transition phenomena by using Gibbs measures

Effects of Compound Fertilization on Growth and Alkaloids of Datura (Datura innoxia Mill.) Plants

The effect of 0, 100, 200, 400, 600 and 800 kg ha−1 of Sangral, a complex chemical fertilizer at rates, on growth, alkaloid content, drug yield and nutrient uptake of datura (Datura innoxia Mill.) plants was studied during two successive seasons. The plant height, the number of branches and leaves/plant, the fresh and the dry weights increased with increasing fertilizer rates up to 800 kg ha−1; however, the maximum increase was recorded at 600 kg ha−1. Total alkaloid and drug (hyoscyamine + scopolamine) contents also increased with increasing the fertilization level to a peak value of 600 kg ha−1. It then, decreased at 800 kg ha−1 level. Plant leaves and fruits were the most valuable organs for alkaloid and drug accumulation followed by stems, roots and crowns, respectively. N, P and K in the leaves were linearly increased by increasing fertilizer level. It seems that compound fertilizers increase the availability of essential nutrient elements necessary for datura growth and metabolism, causing vigorous vegetation and high chemical production

Time-Resolved Photoluminescence of 6-Thienyl-Lumazine Flourophore In Cellulose Acetate Nanofibers For Detection Of Mercury Ions

Time-resolved photoluminescence measurements were used to characterize the photophysical properties of 6-thienyllumazine (TLm) fluorophores in cellulose acetate nanofibers (NFs) in the presence and absence of mercuric acetate salts. In solution, excited-state proton transfer (ESPT) from TLm to water molecules was observed at pH from 2 to 12. The insertion of the thienyl group into lumazine (Lm) introduces cis and trans conformers while keeping the same tautomerization structures. Global and target analysis was employed to resolve the true emission spectra of all prototropic, tautomeric, and rotameric species for TLm in water. However, in the NFs solid film no ESPT from TLm to a nearby water molecule was observed. The addition of NFs increases the excited-state lifetime of TLm in the solid state because of combined polarity/confinement effects. The solid-state fluorescence of TLm (in NFs) was quenched by mercuric acetate through different mechanisms—dynamic and static—depending on the applied pressure—atmospheric and vacuum, respectively. The new solid-state sensor is simple, ecofriendly, and instantly fabricated. 20 μmol TLm-loaded NFs is able to detect down to 200nmol of mercuric ions in aqueous media. The formation of the non-fluorescent ground-state complex between TLm molecules and mercuric ions inside the pores of NFs was achieved under vacuum condition

Studies on Stable Crack Growth

The goal of this work is to experimentally investigate the stable crack growth (SCG) fracture behavior of AISI 4340 alloy steel. A series of mode I and mixed mode SCG fracture tests were carried out on 8 mm thick compact tension (CT) specimens subjected to quasistatic loading. The wire cutting technique was used to introduce a pre-notch/ pre-crack of 0.05 mm root radius to the specimen. Five different loading angles Ψ between the loading axis and the crack surface were employed; 90° (mode I), 75°, 65°, 60° and 50°. Five different ratios of original crack length to specimen width ao/w were also employed, 0.41, 0.42, 0.43, 0.44 and 0.45. Different combinations of Ψ and ao/w were used. Data concerned with direction of initial crack extension load-load line displacement (L-LLD) diagrams, initiation and maximum loads, range of stable crack growth, crack blunting, crack front geometry, fracture surfaces, and scanning electron microscope fracto graphs were obtained. A noticeable blunting was observed prior the crack initiation. Although the crack commences its growth from a pre-notch / pre-crack of a straight front it has a considerable tunneling at each stage of stable crack growth. In mixed mode, the crack takes place along a straight-line path initially, inclined with the main crack at an angle equal to the direction of crack extension. The loading angle Ψ and the initial crack length to the specimen width ao/w ratio affect the SCG fracture behavior significantly. The direction of initial stable crack extension was determined through an elastic finite element analysis. There was reasonably good agreement between the experimental and the predicted results

Environmental Catalysis by Nanostructured Chromium Oxides: Methanol Conversion to Dimethyl Ether as a Clean Fuel Alternative

Heterogeneous catalysts which are mainly based on metal particles and metal oxides have shown promising activity and selectivity in several environmental and industrial important reactions. Catalysis plays a key role in chemical and material manufacturing, fuel cells as well as other energy conversion and pollution control systems. Petroleum and fuel industry, in particular, rely largely on heterogeneous catalysis. Since catalysts play such a critical role in essential processes, the search for more effective and selective catalysts continues to be of great importance for both environmental and commercial considerations. The current study focuses on the catalytic conversion of methanol to other fuel alternatives and valuable chemicals, especially dimethyl ether (DME) which has attracted the attention of several companies and researchers due to its potential use as an environmentally clean fuel. Several metal oxide catalysts were investigated in this study including chromium(III) oxide, iron (III)oxide, titanium oxide, aluminum oxide, and several composites based on these oxides. The selection of these systems was based on their known activity in acid-base as well as oxidation-reduction surface reactions. The first part of this work involves various studies aimed at developing cost-effective methods to prepare nano-structured chromium(III) oxide-based catalysts. Pure chromium oxide and chromium oxide-containing catalysts have been prepared by sol gel and forced precipitation methods. These are appropriate preparative methods for the synthesis of ultra-fine oxide materials at relatively low temperatures and reasonable cost. The effect of chromium on the composition and textural properties was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), FTIR spectroscopy, and N2 adsorption. In the second part of this work, the activity and selectivity of these catalysts in methanol conversion to dimethyl ether (DME) and other valuable chemicals was investigated. This study involved all chromium mixed oxides as well as prepared and commercial corresponding pure oxides. Comparison between the catalysts and correlation between the catalysts\u27 activity and the composition as well as textural characteristics were established

Internet-based monitoring and controlling of real-time dynamic systems

The study in this report mainly focuses on the Internet-based Monitoring and Controlling of a Real-Time Dynamic System interfaced via a dedicated local computer. The main philosophy behind this study is to allow the remote user to conduct an Internet-based Remote Operation (I-bRO) for the dynamic system. The dynamic system has been defined as the system which has its parts interrelated in such a way that a change in one part necessarily affects other parts of the system [I]. In order to achieve this goal, the study has been conducted in a form of an on-line and real-time Virtual Laboratory (VL). Through this form of laboratory, a user can carry out the experiment, perform real-time monitoring and controlling operations of the experiment and collect real and live data from the experiment through the network link as the user was physically in the laboratory. The dynamic system that has been selected for the test-rig of this study is a 3-phase Induction Motor (IM) which is mechanically coupled with a DC-Dynamometer that acts as a variable load to the IM. This system is a common laboratory experiment in the study of the Electrical Engineering for both undergraduate and postgraduate students. The study covers both sides of the I-bRO; the hardware and the software. The hardware side includes the design and the development of a load control box that has been used to interface the DC-Dynamometer and consequently control it from the local computer. The software side covers the design and the development of the Virtual Instrumentation System (VIS) that has replaced successfully the physical Measurement and Test (M&T) instruments of the test-rig. Beside that, the software side includes the development of the internet remote front panel for the remote operation.Furthermore, the software side includes the development of the software that has been used to analyse the system during the I-bRO. In this study, the LabVTEW7 program has been used to design and develop the VIS and the Matlab program has bee used to aualyse the system performance for the remote operations. This study also addresses the issues and problems related to the intranet or the internet to be used as the network for data communication between the test-rig and remote users. This study has been carried out in different stages as follows: 1. Designing and development of the VIS. 2. Interfacing the test-rig apparatus with a local computer. 3. Upload the system from the local computer to the network. 4. Study the performance of the system on the network for the purpose of the remote operations controlled over the internet. The developed system of this study has been used for data acquisition, network communications, instruments monitoring and controlling applications. A user can execute on-line and in the real-time the developed VIS from any point in the university. Due to the fact that the university network is directly integrated to the main internet server. a remote user through the main internet server is able to perform I-bRO of the selected dynamic system. There are many factors associated with the network, the internet or the intranet, and have direct influences on the control system performance throughout the remote operations. The most dominant factors are the random time-delays and the data losses.These factors among others have to be addressed for a proper application of the I-bRO. For this reason, different cases and scenarios of the I-bRO have been investigated and simulated to study the affection of the network on the control system performance. The system is analysed under two control cases, closed loop with random time-delays and open loop when the internet server is disconnected and no communication between the input and the output of the system. In the first case, the closed loop, the internet server is assumed to be closed and subjected to random time-delays. In the second case, the internet server is subjected to random cut-off and thus opens the control loop. The results of both cases have been analysed and discussed. It has been found that, if the control system without the time-delays is stable, it remains stable even with small time-delays up to twenty seconds. This result is different from what has been shown in the literature