Ammonium (NH4+): Nitrate (NO3-) ratio and its relation to the changes in solution pH, growth, mineral nutrition and yield of tomatoes grown in nutrient film technique

The effects of NH4+ NO3- ratio on growth, water uptake, solution pH, mineral nutrition and yield of tomatoes were investigated using the nutrient film technique. There were six NH4+ NO3- ratios: 0:100 with and without pH control; 12.5:87.5, 25:75, 37.5:62.5 and 50:50 without pH control. There was an increase in pH of the nutrient solution with 0:100 and 12.5:87.5 ratios, but the pH decreased with 50:50 ratio. Higher NH4+ NO3- ratio reduced leaf and root growth. The reduction in leafand root growth could be attributed to reduction o fplant water uptake. Fruit fresh weight was reduced and the percentage of blossom-end rot increased with higher ratio of NH4+ NO3- in the solution. Increased ratio of NH4+ NO3- increased N content and decreased Ca content in all the plant tissues. P, K and Mg content decreased in leaf tissue with increasing NH4+ NO3- ratio

Carbon absorption control model of oil palm plantation

Among the largest and growing oil palm industries, Malaysia plays an important role in the world’s oil market. The contribution of the palm plantation in absorbing carbon from the atmosphere is also considerable thought, it is rarely studied. The role of the plantation in balancing carbon dioxide is significant. However, the ability of palm tree in absorbing carbon may vary within the lifespan of the plant. Therefore, managing the plantation to reach the maximum carbon dioxide absorption along with maximum oil production is challenging. This study is aimed at analyzing the carbon absorption level of the palm oil plantation. A mathematical model is proposed by considering the characteristics of palm oil trees in absorbing carbon and producing oil. It is assumed that the rate of felling can be controlled, and a system of ordinary differential equations is developed to describe the behaviour of the plantation in terms of biomass and growth rate dynamics. The resulting parameter estimation problem is solved which leads to an optimal control problem. The objective of this problem was to maximize the oil production as well as carbon absorption. Numerical simulation is illustrated to highlight the application of the proposed model

The optimal felling rate in the palm oil plantation system

Successful oil palm plantation should have high profit, clean and environmental friendly. Since oil palm trees have a long life and it takes years to be fully grown, controlling the felling rate of the oil palm trees is a fundamental challenge. It needs to be addressed in order to maximize oil production. However, a good arrangement of the felling of the oil palm trees may also affect the amount of carbon absorption. The objective of this study is to develop an optimal felling model of the oil palm plantation system taking into account both oil production and carbon absorption. The model facilitates in providing the optimal control of felling rate that results in maximizing both oil production and carbon absorption. With this aim, the model is formulated considering oil palm biomass, carbon absorption rate, oil production rate and the average prices of carbon and oil palm. A set of real data is used to estimate the parameters of the model and numerical simulation is conducted to highlight the application of the proposed model. The resulting parameter estimation that leads to an optimal control of felling rate problem is solved

The validation of assessment for learning audit instrument: a mixed methods approach

The CEFR-aligned curriculum promotes integration in the implementation of Assessment for Learning (AfL) by English language teachers in primary schools. This paper depicts the mixed methods pilot and validation of the Assessment for Learning Audit Instrument (AfLAi) for the purpose of examining the use and understanding of AfL among the teachers in primary schools. In Phase 1, three subject matter experts were consulted, and nine English language teachers provided consensual validation. In Phase 2, 53 English language teachers responded to the adapted instrument. AfLAi was further discussed with the validators in Phase 3. This procedure was adapted from Phase 8 of the Instrument Development and Construct Validation mixed research techniques. Among the emerging themes were on language correction, item/ instrument difficulty, and useful items. The quantitative data was compared with the scales from the original authors regarding the four key strategies of AfL in AfLAi: Sharing Learning Intentions and Success Criteria, Questions and Classroom Discussions, Feedback and Peer- and Self- Assessment. Based on the mixed data arranged in a joint display, some parts in the items were adapted to accommodate the local context. Among the findings were (i) the key strategy known as Learning Intentions in AfLAi was not applicable in the target context, and (ii) some examples in the items needed to be changed to fit the Malaysian syllabus. The implications of this pilot study and validation process included 16 changes in the instrument and the translation of the instrument into Bahasa Melayu

A computational analysis of heat transfer and fluid flow in high-speed scanning of laser micro-welding

A transient three-dimensional model is numerically developed using computational fluid dynamics (CFD) method to understand some critical criteria such as temperature fields and melt pool formation by considering the heat source and the material interaction and the effect of laser welding parameters on laser micro-welding process. To gain more implicit insight of fluid dynamics, the issue of circulation of molten metal assisted by the surface tension, buoyancy and recoil pressure forces in the weld pool has been investigated Assuming that atmospheric and vaporised material pressures are balanced at the front of the laser beam. The governing equations from the Navier–Stokes for Newtonian fluid are prepared to estimate the melt flow that influences the rate of temperature distribution in a 3-D domain. The simulation results have been compared with two sets of experimental research to predict the weld bead geometry and solidification pattern which laser welds are made on thin stainless steel sheet (SUS304). The shape comparison describes those parameters relevant to any changes in the melt dynamics and temperatures are of great importance on the formation of weld pool and heat distribution during laser micro-welding. The fair agreement between simulated and experimental results, demonstrates the reliability of the computed model

Mineral contents of selected marine fish and shellfish from the west coast of Peninsular Malaysia

The study was conducted to determine the mineral contents of 20 species of marine fish and 4 species of shellfish from the west coast of Peninsular Malaysia.Overall, the contents of micro minerals in all samples were below the permissible limits; except for oyster; with copper slightly higher than the limit set by FAO/WHO (1984), but below the limit set by Malaysian Food Regulations (1985); and zinc content higher than the limit set by Malaysian Food Regulations (1985), but below the limit set by FAO/WHO (1984). Meanwhile for macro minerals, most samples contained comparable sodium contents, significantly lower of potassium contents, higher calcium contents, and extremely higher of magnesium contents compared to the common ranges reported in the literatures. All samples were good sources of micro and macro minerals and could provide multi-health benefits if consumed in recommended amounts

Smoothing Solution for Discrete-Time Nonlinear Stochastic Optimal Control Problem with Model-Reality Differences

In this chapter, the performance of the integrated optimal control and parameter estimation (IOCPE) algorithm is improved using a modified fixed-interval smoothing scheme in order to solve the discrete-time nonlinear stochastic optimal control problem. In our approach, a linear model-based optimal control problem with adding the adjustable parameters into the model used is solved iteratively. The aim is to obtain the optimal solution of the original optimal control problem. In the presence of the random noise sequences in process plant and measurement channel, the state dynamics, which is estimated using Kalman filtering theory, is smoothed in a fixed interval. With such smoothed state estimate sequence that reduces the output residual, the feedback optimal control law is then designed. During the computation procedure, the optimal solution of the modified model-based optimal control problem can be updated at each iteration step. When convergence is achieved, the iterative solution approaches to the correct optimal solution of the original optimal control problem, in spite of model-reality differences. Moreover, the convergence of the resulting algorithm is also given. For illustration, optimal control of a continuous stirred-tank reactor problem is studied and the result obtained shows the efficiency of the approach proposed

Modelling of reservoir network for flood control using nonlinear reservoir routing model

Network of reservoirs has become a standard hydraulic construct for multipurpose use. In this work, we present a formulation based on nonlinear reservoir method and coupled tank approach to model the reservoir network for flood control. The network of reservoirs consists of both detention and retention pond which give rise to nonlinear system of ODE for the m reservoirs in the network. The inflow consists of rainfall runoff in each sub catchment and discharges from the adjacent reservoirs. On the other hands, the outflow consists of infiltration and discharges. The nonlinear system obtained is linearized about the normal operating height of each reservoir in the network. The discharge term on the last equation is dropped in order to allow all the runoff captured into it. The establishment of relationship between the area of catchment and area of reservoir give room for the estimation of the forcing function in terms time of concentration rather than in terms of area of the reservoir which is difficult to obtain in an existing network. Two sets of solutions are presented, one at the convergent point and the other the best solution in respect of the lowest point in the reservoirs

The washback effect of the General Secondary English Examination (GSEE) on teaching and learning

This paper reports on a study investigating the washback effect of the General Secondary English Examination (hereinafter referred to as GSEE), a high-stakes exit test for secondary school students (12thgrade) in Yemen. The main aim of this study is to gain preliminary insights into the relationship between teaching and learning factors affected by the washback effect. It focuses on eight pedagogical dimensions: four of them concerned the teachers (teaching methods, teaching experiences, content assessment, and beliefs) and four concerned the students (learning styles, learning activities, attitudes and motivation). A semi-structured interview was conducted with three English teachers who have over ten years of teaching experience. Based on the interview, a questionnaire was constructed and then administered to 30 Yemeni English teachers of the 12thgrade English classes. The data were analysed using SPSS software, version 20. The results showed that the test had a great influence on the learners and teachers mainly on teaching methodology and on learning styles. Triangulation with the qualitative data confirmed the findings. Hence, the study provides a clear evidence of the washback effect of the exam on the components of the language teaching-learning processes in Yemen and its influence on what and how the teachers teach, and the learners learn

Ayfin (M) Sdn. Bhd. / Aizuddin Abd. Aziz ...[et al.]

Ayfin (M) Sdn. Bhd adalah membekalkan komponen-komponen luaran radio bagi kilang-kilang yang mengeluarkan barangan elektroik. Syarikat ini beroperasi di No. 66, Jalan Pinang Tunggal 2, Kempas Light Industry, 08000 Sungai Petani, Kedah