Model of a Corrosion Pit with Movement of Active Boundaries

Pitting is one of the most destructive types of localized corrosion. This paper presents the mathematical model of the early stages of pitting corrosion after its initiation stage, using a commercial finite element program. In view of the chemical and electrochemical reactions inside a single pit in steel, a two dimensional model that allows the prediction of movement of boundaries of a pit is developed

Chemical constituents and lipoxygenase inhibitory activity of Piper stylosum Miq.

ABSTRACT. Chemical constituents and lipoxygenase inhibitory activity of the aerial part of Piper stylosum have been studied. Fractionation and purification of the extracts afforded five lignans, identified as yangambin (1), sesamin (2), syringaresinol (3), pinoresinol (4), and medioresinol (5), together with other constituents; 4-allyl resorcinol, β-sitosterol, β-sitostenone, taraxerol, vanilin, and vanilic acid. The structures of these compounds were established by analysis of their spectral data, as compared to that of reported compounds. The lipoxygenase inhibitory activity of the extracts and isolated lignans were also evaluated.               KEY WORDS: Piperaceae, Piper, Piper stylosum, Lignan, Lipoxygenase Bull. Chem. Soc. Ethiop. 2019, 33(3), 587-592.   DOI: https://dx.doi.org/10.4314/bcse.v33i3.1

Identifying national security fundamentals in the big data of digital asymmetrical environment communication

This conceptualization article discusses the impact of technology to society from variousperspectives which relates on humanities aspect of social convention, hegemony, generation warfare and intelligence constructs.The narratives provide understandings of the current transition, emphasizing the changing need of intelligence protocols to understand the society in current technological advancement era. Intelligence output is detrimental as information is no longer secluded in this borderless communication spheres. The article narrates generation warfare intelligence in complex information system of digital asymmetrical environment in current generation warfare to digest the social implications and of technology to society and provides appropriate recommendations.Keywords: communication; generation warfare; hegemony; intelligence; society; socialconvention

The relationship between ICT adoption and business performance in Malaysia and Indonesia

This paper reviews the relationship of information communication technology adoption (ICT) and Business Performance (BP) from women entrepreneur perspective in Malaysia and Indonesia. The aim of this paper is to identify the dimension of ICT adoption and BP to develop a conceptual framework for further study about the relationship to identify those that can determine women entrepreneur success. To achieve this objective, literature review is conducted by extend number of literature in ICT, BP, and women entrepreneur. Related studies are review and analyze by using literature table. The finding of this paper reveals a proposed conceptual framework and hypothesis that gain support from literature. The significant of this study is expected to provide guideline for women entrepreneurs in Malaysia and Indonesia who wish to adopt ICT in their business and help them to evaluate the relationship with BP. This study can assist women entrepreneurs in considering the adoption of Electronic commerce (EC) and Mobile commerce (MC) to embark themselves in technology and innovation. Further efforts are to test this conceptual framework and hypothesis by using Structural Equation Modelling (SEM) to develop a research model

Implementation of cryptography algorithms in SCADAKratos application

This paper studies cryptography algorithms to be implemented into the SCADAKratos application of thermal vacuum chamber (TVC) system. SCADAKratos application is used to control and monitor the operations of the TVC which is a satellite test equipment that is located at the Malaysia Space Centre, Banting, Malaysia. The security features had been put aside during the development as it was claimed that there is no threat to the system since the system is operated internally. However, during service and troubleshooting by the manufacturer, the system will be accessed through public network. Besides that, the system also can be accessed remotely during operation for control and monitoring purpose. In addition, the testing data results also need to be transferred to the customer through the internet as it is easier and faster. The remote access through public network will cause the TVC system to face a risk to any threat and attack. Therefore, the implementation of cryptography algorithm into TVC system is needed in order to secure and protect the system from unauthorized access. This paper explains the architecture of SCADAKratos application of TVC system and how the cryptography algorithms could be implemented through this application. Secure Hash Algorithm (SHA-1) and AES algorithm (AES) are chosen as the encryption technique which will be applied in the TVC system. Simulation result shows that this technique is feasible for the mentioned implementation

Effects of Current Density and Deposition Time on Corrosion Behaviour of Nickel-based Alloy Coatings

Corrosion of fasteners is an on-going issue and stainless steel 304 (SS304) is prone to this destructive process. One method to mitigate corrosion is electrodeposition of Co-Ni-Fe nanoparticles.  This paper studied the effects of deposition time and current density on corrosion behaviour of Co-Ni-Fe coated SS304 bolt. Co-Ni-Fe ternary alloys were electrodeposited onto SS304 bolt in 15, 30, or 45 minutes by using current density of 28, 35, 42 mA/cm2. Combinations of these parameters produced 9 samples. These samples were electrochemically tested by a potentiostat using open circuit potential (OCP) and potentiodynamic polarization (PDP). The samples were also characterised in terms of surface roughness and thickness of the coatings by using 3D surface metrology system. The OCP value decreased when deposition time was increased. All sample synthesised in 30 minutes had a more stable OCP curve. PDP curves exhibited active behaviour without passivation region. The corrosion potential (Ecorr) of T15 samples was more anodic than T30 and T45 samples. The corrosion current density (Icorr) of all samples fluctuated. Sample synthesised in 30 minutes using 42 mA/cm2 had the lowest corrosion rate. It was found that the surface roughness influences the corrosion behaviour in which a lower surface roughness tends to produce coating with better corrosion performance. Current density had small effect on the thickness of coating, whereas the tendency of a thickness to increase was obvious for deposition time

Effects of Current Density and Deposition Time on Corrosion Behaviour of Nickel-based Alloy Coatings

Corrosion of fasteners is an on-going issue and stainless steel 304 (SS304) is prone to this destructive process. One method to mitigate corrosion is electrodeposition of Co-Ni-Fe nanoparticles.  This paper studied the effects of deposition time and current density on corrosion behaviour of Co-Ni-Fe coated SS304 bolt. Co-Ni-Fe ternary alloys were electrodeposited onto SS304 bolt in 15, 30, or 45 minutes by using current density of 28, 35, 42 mA/cm2. Combinations of these parameters produced 9 samples. These samples were electrochemically tested by a potentiostat using open circuit potential (OCP) and potentiodynamic polarization (PDP). The samples were also characterised in terms of surface roughness and thickness of the coatings by using 3D surface metrology system. The OCP value decreased when deposition time was increased. All sample synthesised in 30 minutes had a more stable OCP curve. PDP curves exhibited active behaviour without passivation region. The corrosion potential (Ecorr) of T15 samples was more anodic than T30 and T45 samples. The corrosion current density (Icorr) of all samples fluctuated. Sample synthesised in 30 minutes using 42 mA/cm2 had the lowest corrosion rate. It was found that the surface roughness influences the corrosion behaviour in which a lower surface roughness tends to produce coating with better corrosion performance. Current density had small effect on the thickness of coating, whereas the tendency of a thickness to increase was obvious for deposition time

Aluminum toxicity in acid sulfate soil alleviated with biogenic liming composites of blood cockle shell and palm kernel shell

Low crop yield from acid sulfate soil was caused by high concentrations of aluminum and iron in soil. Aluminum ion which cause root injury at root region inhibits the uptake of the nutrients by the root and lead to nutrient deficiency. Ground magnesium limestones can beapplied to overcome this problem but incurred more production cost. Biogenic liming agent from blood cockle shell and/or palm kernel shell are more cost effective and provide the essential element i.e. calcium. This study evaluate phase-association of Al in acid sulfate soil remediated using biogenic composites liming material using selective sequential extraction analysis. Biogenic liming composites were characterized for pH, proximate analysis and elemental composition. High ratio of BCS in composite retained Al in the residual form about 91.33%. Amelioration of soil with 100% PKS did not give significant reduction of the exchangeable Al.Keywords: soil remediation; phytotoxicity; abiotic stress; calcination; alkalinity

Semisolid Metal Processing Techniques for Nondendritic Feedstock Production

Semisolid metal (SSM) processing or thixoforming is widely known as a technology that involves the formation of metal alloys between solidus and liquidus temperatures. For the procedure to operate successfully, the microstructure of the starting material must consist of solid near-globular grains surrounded by a liquid matrix and a wide solidus-to-liquidus transition area. Currently, this process is industrially successful, generating a variety of products with high quality parts in various industrial sectors. Throughout the years since its inception, a number of technologies to produce the appropriate globular microstructure have been developed and applied worldwide. The main aim of this paper is to classify the presently available SSM technologies and present a comprehensive review of the potential mechanisms that lead to microstructural alterations during the preparation of feedstock materials for SSM processing

An adaptation of deep learning technique in orbit propagation model using long short-term memory

The orbit propagation model is used to predict the position and velocity of the satellites. It is crucial to obtain accurate predictions to ensure that satellite operation planning is in place and detects any possible disasters. However, the model's accuracy decreases as the propagation span increases if the input data are not updated. Therefore, to minimize these errors while still maintaining the model accuracy, a study is conducted. The Simplified General Perturbations-4 (SGP4) model and two-line elements (TLE) data are selected to perform this study. The problem is analyzed, and the deep learning technique is the proposed method to solve the issue. Next, the enhanced model is validated. The study aims to produce a reliable orbit propagation model and assist the satellite's operational planning. Also, the improved model can provide vital information for space-based organizations and anyone who may be affected