Microstructure Alterations of Ti-6Al-4V ELI during Turning by Using Tungsten Carbide Inserts under Dry Cutting Condition

Titanium alloys possesses a hexagonal close packed(h.c.p) structure, called phase to ambient temperature. Thisstructure changes to body center cubic (b.c.c), called phase tothe temperature of 882 C. Machining process that generates hightemperature during machining can affect on microstructures ofmachined surface, which represents as a quality of components.The turning parameters evaluated are cutting speed (55 - 95m/min), feed rate (0.15 - 0.35 mm/rev), depth of cut (0.10 - 0.20mm) and tool grade (uncoated, CVD and PVD). The aims of thispaper are to investigate the effects of machining process onmicrostructures of machined surface and chip were machinedusing tungsten carbide inserts under dry cutting condition. Theresults show that machining at high cutting speed (95 m/min)affected on the microstructure significantly at the end ofmachining. The temperature is the most significant factoraffected on microstructure of the machined surface and chip atshear zone. The changes of microstructure were also affected bythe tool pressure during cutting

Multiresolution discrete finite difference masks for rapid solution approximation of the Poisson's equation

YesThe Poisson's equation is an essential entity of applied mathematics for modelling many phenomena of importance. They include the theory of gravitation, electromagnetism, fluid flows and geometric design. In this regard, finding efficient solution methods for the Poisson's equation is a significant problem that requires addressing. In this paper, we show how it is possible to generate approximate solutions of the Poisson's equation subject to various boundary conditions. We make use of the discrete finite difference operator, which, in many ways, is similar to the standard finite difference method for numerically solving partial differential equations. Our approach is based upon the Laplacian averaging operator which, as we show, can be elegantly applied over many folds in a computationally efficient manner to obtain a close approximation to the solution of the equation at hand. We compare our method by way of examples with the solutions arising from the analytic variants as well as the numerical variants of the Poisson's equation subject to a given set of boundary conditions. Thus, we show that our method, though simple to implement yet computationally very efficient, is powerful enough to generate approximate solutions of the Poisson's equation.Supported by the European Union’s Horizon 2020 Programme H2020-MSCA-RISE-2017, under the project PDE-GIR with grant number 778035

Corporate Governance and Earnings Conservatism in Malaysia

Purpose: This paper aims to investigate whether the revised Malaysian Code on Corporate Governance in 2007 enhances earnings conservatism. In addition, the authors examine the relationship between board of directors’ expertise and conservatism. The third objective is to investigate the relationship between audit committee characteristics and earnings conservatism. Design/methodology/approach: The sample of this study is based on 3,183 firm-year observations for a period of 2004-2009. The authors hand collected the corporate governance variables, whereas the remaining data were extracted from Compustat Global. The authors used two measures of conservatism. The first is the market-based model by Basu’s (1997), and the second measure is the accrual-based measure by Ball and Shivakumar (2005). Findings: The authors find that the revision of Malaysian Code on Corporate Governance 2007 results in improving earnings conservatism. The authors find two audit committee characteristics, namely, audit committee financial expertise and independence increase earnings conservatism, after 2007. However, the authors could not find support whether board financial expertise mix affect conservatism. Research limitations/implications: This study did not consider other possible corporate governance variables that could influence earnings conservatism, as it would be a difficult task to gather them. Originality/value: The authors provide evidence on the role of corporate governance and earnings conservatism in Malaysia

ENHANCING THE CULTURAL IDENTITY BY USING ISLAMIC ORNAMENT IN CONTEMPORARY INTERIOR DESIGN

Islamic buildings have their unique Islamic architectural style that distinguishes its identity. These buildings show habits, traditions, and Islamic ideology. Buildings have been affected by Western art because of technological development in different parts of culture, economic, arts, and sciences. Thus, they have not any cultural identity. Islamic ornament is full of aesthetic andartistic values. It has different designs can be used whether inside or outside buildings. The study aims to investigate why designers do not use this art in contemporary buildings. The study concludes that the causes, contributed to the decline to use ornament in buildings, are lack of knowledge of this art, high financial cost, and people want modern designs. The study suggestssolutions to enhance the cultural identity as follows: teaching this art in schools and universities, awareness and educational campaigns, and reformulation of this art with a modern vision

Effect of Rake Angle on Stress, Strain and Temperature on the Edge of Carbide Cutting Tool in Orthogonal Cutting Using FEM Simulation

Demand for higher productivity and good quality for machining parts has encourage many researchers to study the effects of machining parameters using FEM simulation using either two or three dimensions version. These are due to advantages such as software package and computational times are required. Experimental work is very costly, time consuming and labor intensive. The present work aims to simulate a three-dimensional orthogonal cutting operations using FEM software (deform-3D) to study the effects of rake angle on the cutting force, effective stress, strain and temperature on the edge of carbide cutting tool. There were seven runs of simulations. All simulations were performed for various rake angles of -15 deg, -10 deg, -5 deg, 0 deg, +5 deg, +10 deg, and +15 deg. The cutting speed, feed rate and depth of cut (DOC) were kept constant at 100 m/min, 0.35 mm/rev and 0.3 mm respectively. The work piece used was ductile cast iron FCD500 grade and the cutting tool was DNMA432 series (tungsten, uncoated carbide tool, SCEA = 0; and radius angle 55 deg). The analysis of results show that, the increase in the rake angle from negative to positive angle, causing the decrease in cutting force, effective stress and total Von Misses strain. The minimum of the cutting force, effective stress and total Von Misses strain were obtained at rake angle of +15 deg. Increasing the rake caused higher temperature generated on the edge of carbide cutting tool and resulted in bigger contact area between the clearance face and the workpiece, consequently caused more friction and wear. The biggest deformation was occurred in the primary deformation zone, followed by the secondary deformation zone. The highest stress was also occurred in the primary deformation zone. But the highest temperature on the chip usually occurs in secondary deformation zone, especially in the sliding region, because the heat that was generated in the sticking region increased as the workpiece was adhered by the tool and later it was sheared in high frictional force

Firefly algorithm approach for rational bézier border reconstruction of skin lesions from macroscopic medical images

Image segmentation is a fundamental step for image processing of medical images. One of the most important tasks in this step is border reconstruction, which consists of constructing a border curve separating the organ or tissue of interest from the image background. This problem can be formulated as an optimization problem, where the border curve is computed through data fitting procedures from a collection of data points assumed to lie on the boundary of the object under analysis. However, standard mathematical optimization techniques do not provide satisfactory solutions to this problem. Some recent papers have applied evolutionary computation techniques to tackle this issue. Such works are only focused on the polynomial case, ignoring the more powerful (but also more difficult) case of rational curves. In this paper, we address this problem with rational Bézier curves by applying the firefly algorithm, a popular bio-inspired swarm intelligence technique for optimization. Experimental results on medical images of melanomas show that this method performs well and can be successfully applied to this problem

Microstructure Alterations of Ti-6Al-4V ELI During Turning by Using Tungsten Carbide Inserts Under Dry Cutting Condition

Titanium alloys possesses a hexagonal close packed(h.c.p) structure, called phase to ambient temperature. Thisstructure changes to body center cubic (b.c.c), called phase tothe temperature of 882 C. Machining process that generates hightemperature during machining can affect on microstructures ofmachined surface, which represents as a quality of components.The turning parameters evaluated are cutting speed (55 - 95m/min), feed rate (0.15 - 0.35 mm/rev), depth of cut (0.10 - 0.20mm) and tool grade (uncoated, CVD and PVD). The aims of thispaper are to investigate the effects of machining process onmicrostructures of machined surface and chip were machinedusing tungsten carbide inserts under dry cutting condition. Theresults show that machining at high cutting speed (95 m/min)affected on the microstructure significantly at the end ofmachining. The temperature is the most significant factoraffected on microstructure of the machined surface and chip atshear zone. The changes of microstructure were also affected bythe tool pressure during cutting

Comparison effect of delamination factor (Fd) on unidirectional and woven kenaf fibre reinforced plastic composite materials during milling process [Pembandingan kesan faktor pelekangan (Fd) ke atas bahan komposit plastik bertetulang ekaarah dan bertenun semasa proses pemesinan kisar]

Serabut kenaf merupakan salah satu serabut berasaskan tumbuhan di dalam kumpulan serabut asli yang semakin luas penggunaannya. Serabut kenaf dicampurkan dengan bahan plastik (epoksi) bagi menghasilkan suatu bahan baharu dengan sifat mekanikal yang baik dengan kos pembuatan yang rendah. Bahan kerja ini terbahagi kepada dua jenis iaitu serabut kenaf ekaarah dan serabut kenaf tenunan. Uji kaji ini akan menumpukan kepada pembandingan kesan faktor pelekangan Fd yang terhasil semasa proses pemesinan kisar ke atas bahan komposit tersebut dengan penentuan set parameter mesin yang paling optimum bagi mengurangkan kesan Fd. Uji kaji dijalankan berdasarkan analisis kaedah gerak balas permukaan (RSM) dengan pendekatan reka bentuk Box-Behnken bagi mendapatkan hasil faktor bersandar terhadap sambutan. Faktor yang terlibat adalah kelajuan pemotongan, kadar suapan dan kedalaman pemotongan. Proses pengisaran secara lelurus (lurah) dilakukan bagi melihat kesan Fd yang terhasil dengan menggunakan perkakasan mata alat jenis Keluli Berkelajuan Tinggi (HSS) tidak bersalut hujung rata berdiameter 10 mm. Imej daripada mikroskop menunjukkan bahan komposit serabut kenaf ekaarah menghasilkan faktor pelekangan yang tinggi berbanding kesan ke atas bahan komposit serabut kenaf bertenun. Bagi set parameter optimum pula, bahan kerja serabut kenaf ekaarah ialah kelajuan pemotongan, kadar suapan dan kedalaman pemotongan yang rendah. Manakala bagi bahan kerja serabut kenaf bertenun, set parameter optimum adalah kelajuan pemotongan yang rendah dengan kadar suapan dan kedalaman pemotongan yang tinggi