Third-order explicit two-step Runge-Kutta-Nyström method for solving second-order ordinary differential equations

A two-stage explicit two-step Runge-Kutta-Nyström (TSRKN) method is constructed for the numerical integration of special second-order IVPs. Algebraic order conditions of the method are obtained and third-order method is derived. A standard set of test problems are tested and comparisons on the numerical results are made with existing Runge-Kutta-Nyström (RKN) and Runge-Kutta (RK) methods of the same order using constant step size. The numerical results show's its clear advantage in terms of function evaluation

A three-stage explicit two-step Runge-Kutta-Nyström method for solving second-order ordinary differential equations

A three-stage explicit two-step Runge-Kutta-Nyström (TSRKN) method is developed for the numerical integration of special second-order ordinary differential equations. Algebraic order conditions of the method are obtained and fourth-order method is derived. The second-order initial value problems of ordinary differential equations (ODEs) are solved directly using TSRKN and Runge-Kutta-Nyström (RKN) methods. The problems were then reduced to first-order system when solved by Runge-Kutta (RK) method. Numerical comparison of this new method with the existing RK and RKN methods of the same order using constant step size are carried out to illustrate its efficiency and it shows that the new method has clear advantage in terms of function evaluation

Predicting the capability of oxidized cnw adsorbents for the remediation of copper under optimal operating conditions using rsm and ann models

Metal pollutants such as copper released into the aqueous environment have been increasing as a result of anthropogenic activities. Adsorption-based treatment technologies offer opportunities to remediate metal pollutants from municipal and industrial wastewater effluent. The aim of this work was to evaluate the capability of modified cellulose nanowhisker (CNW) adsorbents for the remediation of copper from water matrices under realistic conditions using response surface methodology (RSM) and artificial neural network (ANN) models. Considerations for design and application to remediate Cu(II) from wastewater by developing a continuous flow experiment are described in this study. However, the physical structure of modified CNW adsorbents renders them unsuitable for use in column operation. Therefore, a more detailed study of the mechanical properties of CNW adsorbents would be necessary in order to improve the strength and stability of the adsorbents. This work has demonstrated that modified CNW are promising adsorbents to remediate copper from water matrices under realistic conditions including wastewater complexity and variability. The use of models to predict the test parameter system and account for matrix variability when evaluating CNW adsorbents for remediating Cu from a real-world wastewater matrix may also provide the foundation for assessing other treatment technologies in the future

Embedded explicit two-step runge-kutta-nystr¨om for solving special second-order IVPs

A third-order three-stage explicit Two-step Runge-Kutta-Nystr¨om (TSRKN) method embedded into fourth-order three-stage TSRKN method is developed to solve special second-order initial value problems (IVPs) directly. The stability of the method is investigated. Numerical results are obtained by solving a standard set of test problems, which then reduced to first-order system when solved using Runge-Kutta (RK) method and comparison are made with existing RK method with same order using variable step-size. The results clearly showed the advantage and the efficiency of the new method

Building a knowledge-based system for river water quality management.

Managing water quality is considered most challenging due to the multitasking decision making and the necessity of the convergence of opinion by multidisplinary experts in the field. Many decision making models have been developed with various application tools for water quality management. Knowledge-base system-river water quality (KBS-RWQ) is a system developed using visual basic as the language platform to assist non experts in decision making in managing water quality. Application of the pollutant load concept by using the load duration curve to determine the status of water quality is the basis for the KBS-RWQ. The objective has been to support decision making addressing the following: determine the load capacity of the selected river; evaluate the field data; decide on the source of pollutant; and select control strategies. Deterioration of water quality with health threats to human kind are the result of poor planning and decision making of the past. By combining the the capable modeling technique, databases, and expert intelligence, the KBS-RWQ will improve the quality of the decision making

E-mathematics : pre-instructional and supplement instruction and their impact of student's online participation and final exam score

Open University Malaysia(OUM),Malaysia's first open and distance learning with over 70,000 students, offers more than 51 programsto-date. More than 90% of its students are working adults who are unable to leave their jobs or families behind to pursue their dream of getting a degree.The blended learning approach adoptedby OUM provides the flexibility for working adult's to obtain the required paper qualification and to upgrade their knowledge. One of the important elements of blended learning is the use of online discussion forum where learning takes place beyond classroom. Mathematics,a traditionally difficult course,forms part of thepre-requisite for students to obtaina business degree at OUM. The adult learners at OUM generally have left school for at least five years and most of them have low grades in Mathematics at O'Level. Thus it is a big challenge for these adult learners to undertake a Mathematics course via online with minimum Face-to-Face contact with their tutors. This paper focuses on the implementation of pro-instruction workshop and supplemental instruction to find its impact on student's online participation and exam results of 88 students. The contents of the online forum were also analyzed using a 34-item instrument derived from the Community of Inquiry model

Properties of paper manufactured from kenaf as function of alkaline pH medium and retention of precipitated calcium carbonate

The objective of this study was to have a better understanding of the effect of alkaline pH medium in the retention of filler in papermaking using kenaf bleached pulp. Three stages of experiments were carried out involving papermaking at alkaline pH medium 8 to 13, usage of precipitated calcium carbonate (PCC), Albacar (ABC) of needle-shaped and Albafil (ABF) of circular-shaped, and the application of low and high molecular weight of polyacrylamides (PAM LM and PAM HM). Paper samples were manufactured based on TAPPI Test Method T295 om-88. Characterisation of specimens in terms of filler content, tensile, tear and burst strength were carried out. The results showed that pH medium influenced the inter-fibre bonding of the fibres during papermaking whereby pH 8-9 is found as the best medium in producing stronger paper. The findings are significant in order to suit the pH according to certain shape and size of such fillers

Design of L-Band Multiwavelength Laser for TDM/WDM PON Application

      يقدم هذا البحث عن تصميم ليزر L-Band متعدد الطول الموجي لتطبيقات الشبكة البصرية المنفعلة (PON) بتقسيم الوقت الهجين / تعدد الإرسال بتقسيم الطول الموجي (TDM / WDM). في هذا التصميم ، تم تصميم ليزر الطول الموجي ذو النطاق L ليكون بمثابة إشارات المصب لـ TDM / WDM PON. تتراوح إشارات المصب من 1569.865 نانومتر إلى 1581.973 نانومتر مع تباعد 100 جيجا هرتز. تم تصميم الليزر متعدد الطول الموجي باستخدام برنامج OptiSystem وهو مدمج في TDM / WDM PON المصمم أيضًا باستخدام برنامج محاكاة OptiSystem. من خلال تكييف ليزر الألياف متعدد الطول الموجي في شبكة TDM / WDM ، يتم اقتراح إشارة بسيطة ومنخفضة التكلفة في اتجاه مجرى النهر. من تصميم المحاكاة ، وجد أن التصميم المقترح مناسب للاستخدام في TDM / WDM PON لما يصل إلى 64 وحدة شبكة بصرية (ONUs).This paper presents on the design of L-Band Multiwavelength laser for Hybrid Time Division Multiplexing/ Wavelength Division Multiplexing (TDM/WDM) Passive Optical Network (PON) application. In this design, an L-band Mulltiwavelength Laser is designed as the downstream signals for TDM/WDM PON. The downstream signals ranging from 1569.865 nm to 1581.973 nm with 100GHz spacing. The multiwavelength laser is designed using OptiSystem software and it is integrated into a TDM/WDM PON that is also designed using OptiSystem simulation software. By adapting multiwavelength fiber laser into a TDM/WDM network, a simple and low-cost downstream signal is proposed. From the simulation design, it is found that the proposed design is suitable to be used in TDM/WDM PON for up to 64 Optical Network Units (ONUs)

Antiviral, cyototoxic and antimicrobial activities of anthraquinones isolated from the roots of Morinda elliptica

2-Formyl-1-hydroxyanthraquinone, along with ten other known anthraquinones (1-hydroxy-2-methylanthraquinone, nordamnacanthal, damnacanthal, lucidin-?-methyl ether, rubiadin, rubiadin-1-methyl ether, soranjidiol, morindone, morindone-5-methyl ether and alizarin-1-methyl ether), isolated from the roots of Morinda elliptica , were assayed for anti-HIV, cytotoxic and antimicrobial activites. Only damnacanthal showed moderate activity against HIV. It was cytotoxic towards the MCF-7 (breast carcinoma) and CEM-SS (T-lymphoblastic leukaemia) cell line. Nordamnacanthal was very cytotoxic against the CEM-SS cell lines. Other anthraquinones that showed strong cytotoxicity towards the cell lines tested were lucidin-?-methyl ether (CEM-SS and MCF-7) and rubiadin (CEM-SS). Three anthraquinones viz., nordamnacanthal, damnacanthal and morindone, were found to have strong antimicrobial activity