bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Engineering of Stainless Steels
Authors: Davis J.R.
Published: December 2018

Passivation; pickling, that is, acid descaling; electropolishing; and mechanical cleaning are important surface treatments for the successful performance of stainless steel used for piping, pressure vessels, tanks, and machined parts in a wide variety of applications. This article provides an overview of the various types of stainless steels and describes the commonly used cleaning methods, namely, alkaline cleaning, emulsion cleaning, solvent cleaning, vapor degreasing, ultrasonic cleaning, and acid cleaning. Finishing operations of stainless steels, such as grinding, polishing, and buffing, are reviewed. The article also explains the procedures of electrocleaning, electropolishing, electroplating, painting, surface blackening, coloring, terne coatings, and thermal spraying. It includes useful information on the surface modification of stainless steels, namely, ion implantation and laser surface processing. Surface hardening techniques, namely, nitriding, carburizing, boriding, and flame hardening, performed to improve the resistance of stainless steel alloys are also reviewed.
Thermal Spray Processes
Authors: Crawmer Daryl E.
Published: December 2018

This article presents the major thermal spray processes and their subsets, presenting each of the commercially significant processes together with some of their important variations. Each process is presented along with the attributes that influence coating structure and performance. The article summarizes the essential equipment components and necessary controls. The various thermal spray processes are conventional flame spray, detonation gun, high-velocity oxyfuel spray, electric arc spray, and plasma arc spray. Other processes, such as cold spray, underwater plasma arc spray, and extended-arc and other high-energy plasma arc spray, are also considered.
Introduction to Metal Powder Production and Characterization
Authors: Schade Chris
Published: December 2018

Various powder production processes allow precise control of the chemical composition and physical characteristics of powders and allow tailoring of specific attributes for targeted applications. Metal powders are produced by either mechanical methods or chemical methods. The commonly used mechanical methods include water and gas atomization, milling, mechanical alloying, and electrolysis. Some chemical methods include reduction of oxides. This article provides information on the reliable techniques for powder characterization and testing to evaluate the chemical and physical properties of metal powders, both as individual particles and in bulk forms.
Powder Metallurgy Nickel and Nickel Alloys
Authors: Koehler Lou
Published: December 2018

This article discusses the methods for producing powder metallurgy (PM) nickel powders, including carbonyl process, hydrometallurgical process, hydrogen reduction process, and atomization process, as well as their applications. It describes three processes for producing nickel alloy powders: water atomization, high-pressure water atomization, and gas atomization. The article also provides information on the applications of PM hot isostatic pressing in the oil and gas industry.
Metallography and Microstructures of Carbon and Low-Alloy Steels
Authors: Bramfitt Bruce L. , Lawrence Samuel J.
Published: December 2018

This article describes the microstructure and metallographic practices used for medium- to high-carbon steels as well as for low-alloy steels. It explains the microstructural constituents of plain carbon and low-alloy steels, including ferrite, pearlite, and cementite. The article provides information on how to reveal the various constituents using proven metallographic procedures for both macrostructural and microstructural examination. Emphasis is placed on the specimen preparation procedures such as sectioning, mounting, grinding, and polishing. The article illustrates the use of proven etching techniques for plain carbon and low-alloy steels.
Metallography and Microstructures of Semisolid Formed Alloys
Authors: Vinarcik Edward J.
Published: December 2018

This article begins with a description of indirect and direct semisolid metalworking processes. It then provides information on alloy compositions of common aluminum semisolid metalworking alloys and primary die-cast magnesium alloys in a tabular form. The article describes the macroscopic examination of defects, which occur in semisolid metalworking with illustrations. It discusses the macroscopic examination of gating systems and semisolid feedstocks. The article also provides information on feedstock microstructures, direct semisolid metalworking component microstructures, and indirect semisolid metalworking component microstructures of series 300 aluminum casting alloys and magnesium die-casting alloys.
Corrosion of Nickel and Nickel-Base Alloys
Authors: Crook Paul
Published: December 2018

This article reviews the corrosion behavior in various environments for seven important nickel alloy families: commercially pure nickel, Ni-Cu, Ni-Mo, Ni-Cr, Ni-Cr-Mo, Ni-Cr-Fe, and Ni-Fe-Cr. It examines the behavior of nickel alloys in corrosive media found in industrial settings. The corrosive media include: hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, nitric acid, organic acids, salts, seawater, and alkalis. The modes of high-temperature corrosion include oxidation, carburization, metal dusting, sulfidation, nitridation, corrosion by halogens, and corrosion by molten salts. Applications where the corrosion properties of nickel alloys are important factors in materials selection include the petroleum, chemical, and electrical power industries. Most nickel alloys are much more resistant than the stainless steels to reducing acids, such as hydrochloric, and some are extremely resistant to the chloride-induced phenomena of pitting, crevice attack, and stress-corrosion cracking (to which the stainless steels are susceptible). Nickel alloys are also among the few metallic materials able to cope with hot hydrofluoric acid. The conditions where nickel alloys suffer environmentally assisted cracking are highly specific and therefore avoidable by proper design of the industrial components.
Corrosion of Uranium and Uranium Alloys
Authors: Lillard Jennifer A. , Hanrahan Robert J.
Published: December 2018

This article reviews general corrosion of uranium and its alloys under atmospheric and aqueous exposure as well as with gaseous environments. It describes the dependence of uranium and uranium alloy corrosion on microstructure, alloying, solution chemistry, and temperature as well as galvanic interactions between uranium, its alloys, and other metals. The article provides information on the atmospheric corrosion of uranium based on oxidation in dry air or oxygen, water vapor, and oxygen-water vapor mixtures depending upon particular storage conditions. The mechanism and morphology of hydride corrosion of uranium are discussed. The article provides information on environmentally assisted cracking, protective coatings, and surface modification of uranium and its alloys. It also summarizes the environmental, safety, and health considerations for their use.
Corrosion of Zinc and Zinc Alloys
Authors: Zhang X. Gregory
Published: December 2018

Zinc is one of the most used metals, ranking fourth in worldwide production and consumption behind iron, aluminum, and copper. This article commences with an overview of the applications of zinc that can be divided into six categories: coatings, casting alloys, alloying element in brass and other alloys, wrought zinc alloys, zinc oxide, and zinc chemicals. It discusses the corrosion and electrochemical behavior of zinc and its alloys in various environments, particularly in atmospheres in which they are most widely used. The article tabulates the corrosion rates of zinc and zinc coatings immersed in various types of waters, in different solutions in the neutral pH range, and in soils at different geographic locations in the United States. It concludes with information on the forms of corrosion encountered in zinc coatings, including galvanic corrosion, pitting corrosion, and intergranular corrosion.
Corrosion of Brazed and Soldered Joints
Authors: Dighe Manish
Published: December 2018

Corrosion is often thought of as rusting, the process of deterioration undergone by a metal when it is exposed to air or water. This article provides the fundamentals of joints corrosion and primarily addresses the various forms of corrosion observed in brazed and soldered joints and their causes. It describes the role of proper brazing procedures in controlling corrosion. The article concludes with information on the corrosion resistance of various brazing alloy systems.
High-Velocity Metal Forming
Authors: Daehn Glenn S.
Published: December 2018

This article emphasizes the traits that are common to high-velocity forming operations. It describes general principles on how metal forming is accomplished and analyzed when inertial forces are large. The article discusses the principal methods of high-velocity forming, such as explosive forming, electrohydraulic forming, and electromagnetic forming. It provides examples that illustrate how these methods can be practically applied. The article concludes with information on the status and development potential for the technology.
Metalcasting Technology and the Purchasing Process
Authors:   American Foundry Society Technical Department
Published: December 2018

This article describes the four basic steps of the purchasing process of cast components. The steps include defining requirements and developing a purchasing plan; requesting and evaluating bids from potential sources; selecting a source and negotiating contract terms; and carrying out the contract and pursuing continuous improvement. It provides guidance on purchasing cast components and describes specific issues and approaches that have proved useful in purchasing castings. The article presents a list of the most significant considerations when attempting to determine the overall cost and design requirements of a metal casting.
Modification of Aluminum-Silicon Alloys
Authors: Sigworth G.K.
Published: December 2018

This article focuses on aspects important for the commercial production of castings. It discusses the modification process in hypoeutectic and eutectic alloys that differ only in the relative volume fraction of primary aluminum and aluminum-silicon eutectic. The article explains how modification changes porosity formation in a casting. It describes the mechanisms responsible for silicon modification, as well as the modifications and changes in eutectic nucleation and eutectic grain structure. The article reviews the usage of strontium during process steps in foundry practices. The growth of silicon eutectic is described to explain effects ancillary to silicon modification. The article also discusses the effects of elements, such as phosphorus, antimony, bismuth, magnesium, boron, and calcium, on the silicon structure.
Surface Finish and Surface Integrity
Authors: Field Michael , Kahles John F. , Koster William P.
Published: December 2018

This article distinguishes between a surface finish and a surface texture. It provides information on the surface integrity technology that describes and controls the many possible alterations produced in a surface layer during manufacture, including their effects on material properties and the performance of the surface in service. The types of surface alterations associated with metal removal practices are described. The article discusses the surface roughness, surface integrity, and produced in manufacturing processes, and mechanical property effects. Surface alterations associated with metal removal practices of traditional and nontraditional machining operations, as well as their effect on the static mechanical properties of materials, are reviewed. Finally, the article provides guidelines for material removal, postprocessing, and inspection.
P/M High-Speed Tool Steels
Authors: Pinnow Kenneth E. , Stasko William
Published: December 2018

This article describes procedures for producing powder metallurgy high-speed tool steel powder by inert-gas atomization, followed by compaction by hot isostatic pressing. These include the anti-segregation process (ASP) and the crucible particle metallurgy (CPM) process. The article reviews the properties of ASP and CPM and summarizes the procedures to heat treat ASP high-speed tool steels. It discusses the processing steps, advantages, and applications of the FULDENS process that uses water-atomized powders compacted by vacuum sintering. The article also provides information on the applications of tool steels.
Cemented Carbides
Authors: Santhanam A.T. , Tierney P.
Published: December 2018

This article discusses the manufacturing steps and compositions of cemented carbides, as well as their microstructure, classifications, applications, and physical and mechanical properties. It provides information on new tool geometries, tailored substrates, and the application of thin and hard coatings to cemented carbides by chemical vapor deposition and physical vapor deposition. The article also discusses tool wear mechanisms and the methods available for holding the carbide tool.
Cermets
Authors: Gruss Walter W.
Published: December 2018

Cermets are a group of powder metallurgy products consisting of ceramic particles bonded with a metal. This article describes the composition and microstructure of titanium carbide and titanium carbonitride cermets. It tabulates typical properties of titanium carbonitride cermets and compares the properties of cermets and cemented carbides. The article also summarizes the applications of cermet cutting tools.
Adaptive Control
Authors: Koren Yorham , Ulsoy A. Galip
Published: December 2018

This article discusses the types of adaptive control (AC) systems for metal cutting according to the AC strategies used. These include adaptive control with optimization (ACO), adaptive control with constraints (ACC), and geometric adaptive control (GAC). The article details the milling and grinding systems based on the ACO strategy. It reviews the fundamentals of ACC systems followed by a description of a particular ACC system for a turning operation. The article also describes the basic characteristics of GAC systems and presents a particular GAC system for the turning of cylindrical parts. It examines the issues in the AC systems such as tool wear/breakage. Trends in the AC systems such as variable-gain ACC systems and integration of adaptive control into CAD/CAM/CIM systems are also discussed.
Machining of P/M Tool Steels
Authors: Pinnow Kenneth E. , Dorsch Carl J.
Published: December 2018

Wrought powder metallurgy (P/M) high-speed tool steels exhibit better machinability, dimensional control and safety in heat treatment, grindability, and edge toughness during cutting. This article discusses the two stages of machining of P/M tool steels: rough machining, in annealed condition, and finish machining, in hardened-and-tempered condition. It tabulates the composition of commercial crucible particle metallurgy and anti-segregation process tool steels and their typical machining conditions.
Machining of Reactive Metals
Authors: Chandler Harry E.
Published: December 2018

This article focuses on the machining of reactive metals which refer collectively to the elements titanium, hafnium, and zirconium. It provides guidelines for machining titanium and titanium alloys and describes machining operations, such as turning, milling, drilling, tapping, reaming, grinding, and sawing, performed on titanium and its alloys. The article also provides information on electrochemical machining (ECM), chemical milling (CHM), and laser beam machining (LBM) for titanium and titanium alloys. Guidelines for machining zirconium alloys and hafnium are also provided. The article provides a short description of turning, milling, and drilling operations performed on zirconium alloys and hafnium. It also discusses health and safety considerations related to zirconium and hafnium.
Fracture and Structure
Authors: Bowles C. Quinton
Published: December 2018

The cracking process occurs slowly over the service life from various crack growth mechanisms such as fatigue, stress-corrosion cracking, creep, and hydrogen-induced cracking. Each of these mechanisms has certain characteristic features that are used in failure analysis to determine the cause of cracking or crack growth. This article discusses the macroscopic and microscopic basis of understanding and modeling fracture resistance of metals. It describes the four major types of failure modes in engineering alloys, namely, dimpled rupture, ductile striation formation, cleavage or quasicleavage, and intergranular failure. Certain fundamental characteristics of fracture observed in precipitation-hardening alloys, ferrous alloys, titanium alloys are also discussed.
Fatigue Properties in Engineering
Authors: Cameron D.W. , Hoeppner D.W.
Published: December 2018

Fatigue properties are an integral part of materials comparison activities and offer information for structural life estimation in many engineering applications. This article presents three general approaches to fatigue design, with a discussion on their respective attributes. These include infinite-life criterion, finite-life criterion, and damage tolerant criterion. The article describes the individual property requirements of these approaches. It also presents selected examples of properties that reflect some detail of these approaches.
Fatigue Crack Nucleation and Microstructure
Authors: Lukáš Petr
Published: December 2018

This article presents an overview of fatigue crack nucleation from the point of view of the material microstructure and its evolution during cycling. It describes the sites of microcrack nucleation at the free surfaces. The article discusses the relation of dislocation structures and surface relief and reviews the mechanisms of crack nucleation. The damage of material due to crack nucleation, the extent (in terms of the number of cycles) of the nucleation stage, and the factors influencing crack nucleation are discussed.
Behavior of Small Fatigue Cracks
Authors: McClung R. Craig , Chan Kwai S. , Hudak Stephen J. , Davidson David L.
Published: December 2018

This article defines different types of small cracks and identifies the different factors that influence small-crack behavior. Appropriate analysis techniques, including both rigorous scientific and practical engineering treatments, are briefly described. Important material data issues are addressed, including increased scatter in small-crack data and recommended small-crack test methods. The article highlights the applications where small cracks may be particularly important.
Planning and Evaluation of Fatigue Tests
Authors: Maennig Wolfgang-Werner
Published: December 2018

This article describes a scientific approach to the planning and evaluation of fatigue tests based on the determination of probabilities for detected fracture positions within the observed range of fatigue scatter. It schematically illustrates a constant-amplitude stress cycling about a possible mean load that leads to the fracture of a single part or specimen. The article discusses the evaluation of the range of transition and of the finite-endurance range for fatigue curves. It concludes with a discussion on extrapolation from the range of finite endurance into the range of transition.
Fracture Toughness Testing
Authors: Landes John D.
Published: December 2018

This article describes the test methods of fracture toughness, namely, linear-elastic and nonlinear fracture toughness testing methods. Linear-elastic fracture toughness testing includes slow and rapid loading, crack initiation, and crack arrest method. Nonlinear testing comprises JIC testing, J-R curve evaluation, and crack tip opening displacement (CTOD) method. Other methods used include the combined J standard method, the common fracture toughness test, transition fracture toughness testing, and the weldment fracture testing method.
High-Temperature Life Assessment
Authors: Liu A.F.
Published: December 2018

The approaches to spectrum life prediction in components can be classified into two types, namely, history-based methods, using the life-fraction rule or other damage rules, and postservice evaluation methods. This article discusses the variables affecting the material crack growth rate behavior and those essential elements in making spectrum crack growth life prediction. It provides information on life assessment for bulk creep damage.
Thermal and Thermomechanical Fatigue of Structural Alloys
Authors: Sehitoglu Huseyin
Published: December 2018

Structural alloys are commonly subjected to a variety of thermal and thermomechanical loads. This article provides an overview of the experimental methods in thermal fatigue (TF) and thermomechanical fatigue (TMF) and presents experimental results on the structural materials that have been considered in TF and TMF research. Life prediction models and constitutive equations suited for TF and TMF are covered. The structural materials discussed include carbon steels, low-alloy steels, stainless steels, aluminum alloys, and nickel-base high-temperature alloys. The article explains crack initiation and crack propagation in TF and TMF. It describes thermal ratcheting and thermal shock behavior of structural metallic materials. The article concludes with information on life prediction of structural materials under TF and TMF.
Damage Tolerance Certification of Commercial Aircraft
Authors: Swift T.
Published: December 2018

Damage tolerance is a philosophy used for maintaining the structural safety of commercial transport aircrafts. This article describes the structural evaluations necessary to comply with the regulations contained in the Federal Air worthiness Requirements 25.571 whose guidance is given in Advisory Circular 25.571-1A from the Federal Aviation Administration. It provides an overview of the historical evolution of damage tolerance philosophy and presents a discussion of the design philosophies and a summary of the evaluation tasks for damage tolerance certification.
Fatigue and Fracture Properties of Cast Irons
Authors: Lampman S.
Published: December 2018

This article discusses the fatigue and fracture behavior of various types of cast iron, such as gray iron, ductile iron, malleable iron, compacted graphite iron, and white iron, as a function of chemical composition, matrix microstructure, and graphite morphology.
Fatigue and Fracture Properties of Duplex Stainless Steels
Authors: Johansson R.
Published: December 2018

This article reviews the influence of local strains and corrosion fatigue on the initiation of fatigue cracks in duplex stainless steels. It provides useful information on fatigue crack growth, fatigue strength, and fracture toughness of duplex stainless steels. The article discusses the fatigue and fracture behavior of duplex stainless steels during stress-corrosion cracking. It details the elevated-temperature properties of duplex stainless steels, such as creep-fatigue behavior and thermal cycling properties.
Selecting Aluminum Alloys to Resist Failure by Fracture Mechanisms
Authors: Bucci R.J. , Nordmark G. , Starke E.A.
Published: December 2018

This article provides an overview of fatigue and fracture resistance of aluminum alloys. It discusses the characteristics of aluminum alloy classes and the fracture mechanics of aluminum alloys. The article tabulates relative stress-corrosion cracking ratings for high-strength wrought aluminum products. It analyzes the selection of various alloys for stress-corrosion cracking resistance, including aluminum-lithium alloys, copper-free 7XXX alloys, and casting alloys. The article presents a list of typical tensile properties and fatigue limit of aluminum alloys. It also describes the effects of composition, microstructure, thermal treatments, and processing in fatigue crack growth of aluminum alloys.
Concurrent Engineering
Authors: Clausing Don
Published: December 2018

Concurrent engineering is product development that is done by concurrently utilizing all of the relevant information in making each decision. This article discusses the three aspects that must be taken into account for all product development decisions. The aspects include product functionality, production capability, and field-support capability. The concurrent process is carried out by a multifunctional team that integrates the specialties. The article schematically illustrates product design team configurations with subsystem teams and team of subsystem leaders. It discusses the three-step decision-making process, such as requirements, concepts, and improvement, followed by multifunctional product development teams. The article describes the two types of requirements development by multifunctional teams, namely, quality function deployment and functional analysis. It schematically illustrates the integration of product requirements and concept development. The article concludes with a discussion on the improvement of concepts in terms of robust design and mistake minimization.
Life-Cycle Engineering and Design
Authors:   ASM International Materials Life-Cycle Analysis Committee, Portisch Hans H. , Young Steven B. , Sullivan John L. , Harsch Matthias , Schuckert Manfred , Eyerer Peter , Saur Konrad
Published: December 2018

Life-cycle engineering is a part-, system-, or process-related tool for the investigation of environmental parameters based on technical and economic measures. This article focuses on life-cycle engineering as a method for evaluating impacts. It describes the four steps of life-cycle analysis, namely, goal definition and scoping, inventory analysis, impact assessment and interpretation, and improvement analysis. The article discusses the applications of life-cycle analysis results and presents a case history of life-cycle analysis of an automobile fender.
Environmental Aspects of Design
Authors: Fleischmann Shirley T.
Published: December 2018

This article discusses Allenby's two streams for environmental aspects of design: generic and specific concerns. Generic concerns include guidelines that provide the structure in which specific techniques can be developed and used. Specific methods are environmentally responsible for design and specific information that engineers can use. These methods include life cycle assessment, environmental impact assessment, quality function deployment, design for “X”, failure modes and effects analysis, and design for disassembly.
Products Liability and Design
Authors: Smith Charles O.
Published: December 2018

Products liability is a legal term for the action whereby an injured party (plaintiff) seeks to recover damages for personal injury or property loss from a producer and/or seller when the plaintiff alleges that a defective product caused the injury or loss. This article provides information on the legal bases for products liability and definitions for two types of defects: manufacturing defects and design defects. It summarizes other possible defects in design as well as preventive measures.
Dimensional Management and Tolerance Analysis
Authors: Craig Mark
Published: December 2018

The objective of dimensional management is to create a design and process that absorbs as much variation as possible without affecting the function of the product. This article describes the steps followed by the dimensional management process. These include defining product dimensional requirements, determining process and product requirements, ensuring accurate documentation, developing a measurement plan that validates product requirements, establishing manufacturing capabilities versus design intent, and establishing production-to-design feedback loop. The article discusses the simulation model in terms of a functional feature product model, component part variation, assembly method variation, measurement schemes, and assembly sequences.
Documenting and Communicating the Design
Authors: Vrsek Gary
Published: December 2018

Documentation must be focused toward explaining a specific task such as design process, by conveying the needs of product engineering, materials engineering, and manufacturing. This article describes how documentation supports the process of bringing a product to market, who uses the information, and how it serves as a key form of communication, with examples. It discusses the key features that most documents must define. The article describes the requirements of engineering and manufacturing and how drawings are used as a communication medium.
Techno-Economic Issues in Materials Selection
Authors: Clark Joel P. , Roth Richard , Field Frank R.
Published: December 2018

This article provides an overview of cost analysis in materials selection. It discusses the several categories of alternatives for cost analysis. These include rules of thumb, accounting methods, and analytical methods. The article describes the methods for evaluating materials alternatives on the basis of both direct economic costs and indirect social costs. It considers the life cycle costs of alternative body-in-white designs and life cycle analysis. The various elements of cost are introduced with a case study concerned with the manufacture, use, and disposal of the automobile body-in-white.
Fundamental Structure-Property Relationships in Engineering Materials
Authors: Courtney Thomas H.
Published: December 2018

This article focuses on the relationships among material properties and material structure. It summarizes the fundamental characteristics of metals, ceramics, and polymers. The article provides information on the crystal structure, the atomic coordination, and crystalline defects. It discusses the relevance of the properties to design. The article describes the common means for increasing low-temperature strength and presents an example that shows structure-property relationships in nickel-base superalloys for high-temperature applications. The relationships of microstructure with low-temperature fracture, high-temperature fracture, and fatigue failure are also discussed.
Introduction to Manufacturing and Design
Authors: Stoll Henry W.
Published: December 2018

This article describes the general concepts and practices related to manufacturing and design. It discusses the activities of design and manufacturing by placing it in the context of the business system that they support. The article presents an overview of the manufacturing technology field from a design and material selection perspective. It provides an insight to the complex relationship among design, material selection, and manufacturing. The article offers information on modern design for manufacturing practices that are widely used in the industry.
Glass Fibers
Authors: Wallenberger Frederick T. , Watson James C. , Li Hong
Published: December 2018

This article discusses the types, oxide composition, as well as mechanical and physical properties of general-purpose and special-purpose glass fibers. It describes the glass melting and fiber forming processes and provides information on important commercial products such as continuous roving, woven roving, fiberglass mat, chopped strand, and textile yarns.
Pultrusion
Authors: Sumerak Joseph E. , Martin Jeffrey D.
Published: December 2018

Pultrusion is a cost-effective automated process for manufacturing continuous, constant cross-section composite profiles. This article describes the process characteristics and advantages of pultrusion. It provides information on the applications of pultrusion and discusses the processing equipment and tooling, the material composition, and the process control essential for a basic understanding of the pultrusion process.
NUMERICAL ANALYSIS OF TUNNEL LED LIGHTING MAINTENANCE FACTOR
Authors: Cengiz Mehmet Sait , CENGIZ ÇIĞDEM
Published: December 2018

ABSTRACT:  It is necessary to periodically maintain lighting equipment in accordance with international standards. Contamination of lamps caused by long-term use of lighting equipment will result in loss of Luminous Flux and optical losses. The decrease in lighting performance poses a visual difficulty for drivers and causes accidents. In this study, the total Maintenance Factor is numerically examined by considering the losses of diffuser and lens for LED lamps used in tunnel lighting. The variation of luminaries performance with years considering Maintenance Factors as regards environmental conditions and features of the luminaries is evaluated to demonstrate the importance of tunnel lighting maintenance. Moreover, to show the importance of LED lamps Maintenance Factor, the variation of illumination levels of LED lamps is analysed under different Maintenance Factors. It is observed that enhancing Maintenance Factor would contribute to energy efficiency.

ABSTRAK: Penjagaan peralatan cahaya secara berkala mengikut piawai kebangsaan adalah amat penting. Pencemaran lampu disebabkan penggunaan peralatan cahaya pada jangka panjang akan menyebabkan kehilangan kilauan kerdipan lampu dan optik. Pengurangan pencahayaan ini menyebabkan kesukaran pandangan pada pemandu dan menyebabkan kemalangan jiwa. Kajian ini mengkaji tentang jumlah Faktor Penjagaan secara numerik dengan mengambil kira pengurangan difuser dan kanta pada lampu LED yang digunakan dalam terowong pencahayaan. Faktor Penjagaan pada perubahan kilauan berdasarkan tahun mengambil kira keadaan sekeliling dan ciri khas kilauan. Tambahan, ini dinilai bagi menunjukkan kepentingan penjagaan terowong pencahayaan dan kepentingan Faktor Penjagaan Lampu LED. Perubahan pada tahap terang pada lampu LED dikaji dengan mengambil kira Faktor Penjagaan. Peningkatan pada Faktor Penjagaan telah didapati dapat menjimatkan tenaga.
WIDE RANGE MODULATION INDEXES FEATURED CARRIER-BASED PWM STEPPED WAVEFORM FOR HALF-BRIDGE MODULAR MULTILEVEL CONVERTERS
Authors: Tohtayong Majdee , Khan Sheroz , YAACOB MASHKURI BIN , Yusoff Siti Hajar , MIDI NUR SHAHIDA BINTI , Ahmed Musse Ahmed Mohamud
Published: December 2018

ABSTRACT: This paper presents simulation results of the influence of wide range modulation index values ( ) in carrier-based PWM strategy for application in generating the stepped waveform. The waveform is tested for application in single-phase half-bridge modular multilevel converters (MMCs) topology. The results presented in this paper include a variation of the fundamental component (50 Hz) in the voltage output.  It also studies total harmonic distortion of the output voltage (THDv) and the output current (THDi) when the modulation index is changed over the linear-modulation region, 0 < < 1. It also explores the effect of a modulation index greater than 1. Moreover, different output voltage shapes, as a consequence of varied  on MMCs, are also illustrated for showing the effect of varying the value of on sub-module of MMCs.

ABSTRAK: Kajian ini berkenaan tentang pengaruh simulasi terhadap pelbagai nilai indeks ( ) berasaskan strategi PWM bagi menghasilkan bentuk gelombang bertingkat. Bentuk gelombang ini diuji untuk aplikasi topologi MMCs. Keputusan menunjukkan variasi pada komponen asas (50Hz) pada voltan akhir. Keputusan menunjukkan jumlah penyelarasan harmonik voltan akhir (THDv) dan arus (THDv) apabila indeks modulasi telah ditukar pada had modulasi linear, 0 < < 1. Ia juga membincangkan tentang kesan indeks modulasi lebih daripada 1. Selain itu, bentuk voltan akhir yang berbeza mengikut perubahan nilai   pada MMCs juga dilampirkan bagi menunjukkan kesan perbezaan nilai    pada sub-modul MMCs.
A Novel method to estimate Economic Replacing Time of Transformer Using Monte Carlo Algorithm and ANN
Authors: Zareian Jahromi Mehdi , Mehrabanjahromi M.Hossein , Tajdinian Mohsen , Allahbakhshi Mehdi
Published: December 2018

A hybrid method for developing a more principled approach is presented to determine the life expectancy of transformers. The approach is constructed on an economic analysis of the transformers operational characteristics in combination Â with the technical issues incorporated in the decision process. In this method, firstly life time of transformer is estimated using a hybrid method based on Monte Carlo algorithm and artificial neural network. Also Pareto distribution function is applied to consider health history of transformer and uncertainty in DP behavior of transformer. In the next step, a method is proposed in order to estimate economic replacement time of transformer. This method is based on the well-known bathtub failure model, containing repairs and scheduled maintenance, in order to achieve at a more economically aim Â replacing decision. This aim is obtained in part by considering the uncertainty intrinsic in transformer failures and the corresponding discontinuations in power. In essence, this method organizes a decision support system for determination the life expectancy of a transformer. Simulation results show the high accuracy and functionality of the proposed approach in estimating economic replacing time of the Transformer.
ABOUT THE SILICON SENSITIVITY OF THE DEEP LEVEL WITH ALTERNATING PRESSURE
Authors: Tursunov Ikrom gulamjonovich , Okhunov Abdurahim Abduraxmonovich , Mamatkarimov Odiljon Oxundadaevich
Published: December 2018

ABSTRACT: This paper discusses the strain sensitivity of silicon with deep levels under variable pressure. It is shown that in the pressure swing in silicon with deep levels, there is a redistribution of the primary spatial inhomogeneities in the distribution of impurities so that the electron-hole relaxation after stress relief will occur in the new potential relief.

ABSTRAK: Kajian ini membincangkan tentang sensitiviti kepekaan strain silikon pada pelbagai tahap dalam tekanan. Keputusan menunjukkan terdapat ketidakharmonian agihan pada spasial utama dalam agihan kotoran dengan ayunan tekanan dalam silikon pada tahap dalam, supaya relaksasi lubang-elektron setelah pelepasan tekanan akan berlaku dalam pelepasan potensi baru.
ADAPTIVE TRIMMED MEAN AUTOREGRESSIVE MODEL FOR REDUCTION OF POISSON NOISE IN SCINTIGRAPHIC IMAGES
Authors: Khan Khan Bahadar , Shahid Muhammad , Ullah Hayat , Rehman Eid , Khan Muhammad Mohsin
Published: December 2018

A 2-D Adaptive Trimmed Mean Autoregressive (ATMAR) model has been proposed for denoising of medical images corrupted with poisson noise. Unfiltered images are divided into smaller chunks and ATMAR model is applied on each chunk separately. In this paper, two 5x5 windows with 40% overlapping are used to predict the center pixel value of the central row. The AR coefficients are updated by sliding both windows forward with 60% shift. The same process is repeated to scan the entire image for prediction of a new denoised image. The Adaptive Trimmed Mean Filter (ATMF) eradicates the lowest and highest variations in pixel values of the ATMAR model denoised image and also average out the remaining neighborhood pixel values. Finally, power-law transformation is applied on the resultant image of the ATMAR model for contrast stretching. Image quality is judged in terms of correlation, Mean Squared Error (MSE), Structural Similarity Index Measure (SSIM) and Peak Signal to Noise Ratio (PSNR) of the image with latest denoising techniques. The proposed technique showed an efficient way to scale down poisson noise in scintigraphic images on a pixel-by-pixel basis.
THE HYDRODYNAMIC COEFFICIENTS FOR OSCILLATING 2D RECTANGULAR BOX USING WEAKLY COMPRESSIBLE SMOOTHED PARTICLE HYDRODYNAMICS (WCSPH) METHOD
Authors: Ramli Muhammad Zahir
Published: December 2018

ABSTRACT: An implementation of the weakly compressible smoothed particle hydrodynamics (WCSPH) method is demonstrated to determine the hydrodynamics coefficients through radiation problem of an oscillating 2D rectangular box. Three possible modes of motion namely swaying, heaving, and rolling are carried out to establish the influence of oscillating motions in predicting the added mass and damping. Both solid boundary and fluid flow are modelled by WCSPH and validated by the potential flow and experimental results. Discrepancies observed at lower frequencies are further investigated using different particle resolutions, different time steps, and extending the domain with longer runtime to demonstrate the performance of WCSPH. Finally, flow separation and vortices are discussed and compared with experimental results.

ABSTRAK: Bagi fenomena yang melibatkan radiasi dalam air, segiempat kotak 2D diosilasikan dengan menggunakan simulasi WCSPH untuk memperoleh pekali hidrodinamik. Mod osilasi terbahagi kepada 3 iaitu sway, heave dan roll. Osilasi dengan mengguna pakai kotak akan mempengaruhi pergerakan air dalam menentukan nilai penambahan jisim dan rendaman. Keseluruhan domain air dan sempadan telah dimodelkan dengan menggunakan WCSPH. Semua model tersebut kemudiannya akan dibandingkan melalui keputusan eksperimen dan teori. Jika keputusan melalui kaedah WCSPH ini berbeza, terutama pada frekuensi rendah, penyelidikan lanjut akan dilakukan dengan menggunakan zarah resolusi yang berbeza, langkah masa yang berbeza dan menambah masa domain ujikaji bagi menilai keputusan WCSPH. Akhirnya, kriteria aliran dan kadar pusaran yang terhasil di sekeliling kotak akan dibincang dan dibandingkan bersama keputusan eksperimen.
Chlorella vulgaris logistic growth kinetics model in high concentrations of aqueous ammonia
Authors: Azmi Azlin Suhaida , CHE AZIZ NURAIN ATIKAH , Mohamad Puad Noor Illi , Halim Amanatuzzakiah Abdul , Yusof Faridah , Yusup Suzana
Published: December 2018

ABSTRACT: The ability of microalgae to utilize CO2 during photosynthesis and grow rapidly shows their potential in CO2 bio-fixation to capture and store the gas. However, CO2 capture by this biological approach is very slow compared to chemical reaction-based processes such as absorption using amine or aqueous ammonia. Integration between chemical (aqueous ammonia) and biological (microalgae) aspects might enhance the capturing process and at the same time the microalgae can assimilate CO2 for beneficial bioproduct formation. Thus, it is important to assess the growth of the microalgae in various concentrations of ammonia with CO2 supply. Hence, the main objective of this study is to investigate Chlorella vulgaris growth and its kinetics in aqueous ammonia. To achieve that, C. vulgaris was cultivated in various concentrations of aqueous ammonia between 0 to 1920 mg/L at room temperature (i.e. 27 Â°C) and supplied with 15% (v/v) of CO2 under illumination of 3500 lux of white fluorescent light. Result shows that the maximum growth capacity (Xmax) of C. vulgaris is deteriorating from 1.820 Au to 0.245 Au as the concentration of aqueous ammonia increased. However, no significant change in maximum specific growth rate (Âµmax) was observed. The growth data was then fitted into the logistic growth model. The model coefficient of determination (R2) is decreasing, which suggests modification of the model is required.

ABSTRAK: Keupayaan alga-mikro untuk menggunakan CO2 semasa proses fotosintesis dan pembiakannya yang pesat menunjukkan potensi dalam penggunaan dan penyimpanan gas ketetapan-biologi. Walau bagaimanapun, penggunaan CO2  melalui cara ini adalah sangat perlahan berbanding proses tindak balas kimia melalui penyerapan amina ataupun cecair  ammonia. Percampuran antara tindak balas kimia (cecair ammonia) dan tindak balas biologi, memungkinkan penambahan proses percampuran dan pada masa sama alga-mikro akan menyerap CO2 bagi kepentingan pembentukan hasil biologi. Dengan itu, adalah sangat penting untuk mengawasi pertumbuhan alga-mikro dalam pelbagai ketumpatan ammonia bersama kandungan CO2. Oleh itu, objektif utama penyelidikan ini adalah untuk menyiasat pertumbuhan Chlorella vulgaris dan proses kinetik dalam cecair ammonia. Bagi memperoleh hasil tersebut,  C. vulgaris telah dikulturkan pada ketumpatan cecair berbeza antara 0 ke 1920 mg/L pada suhu bilik (iaitu 27 Â°C) dan dibekalkan dengan 15% (v/v) CO2 di bawah cahaya putih flurosen  3500 lux. Keputusan menunjukkan kapasiti pertumbuhan terbanyak (Xmax) C. vulgaris telah berkurang daripada 1.820 Au kepada 0.245 Au apabila ketumpatan cecair ammonia dikurangkan. Walau bagaimanapun, tiada perubahan ketara pada kadar pertumbuhan (Âµmax) dapat dilihat. Data kadar pertumbuhan kemudiannya dikemas kini pada model pertumbuhan logistik. Model pekali penentu (R2) telah direndahkan di mana cadangan untuk mengubah model adalah diperlukan.
A STUDY ON LOW-COMPLEXITY TRANSMIT ANTENNA SELECTION FOR GENERALIZED SPATIAL MODULATION
Authors: Alafia Adewale , Ajose Simeon Olumide , Imoize Agbotiname Lucky
Published: December 2018

ABSTRACT: Generalized spatial modulation (GSM) maps its information to the index of the transmit antenna combination, making simultaneous transmission of multiple symbol possible. However, SM outperform GSM scheme in terms of error performance of the same data rate, due to average power effect. Transmit and receive diversity or the combination of both allow huge improvement in mimo systems in  terms of error performance. In this paper, we investigate a near optimal low-complexity Euclidean distance antenna selection (LC-EDAS) technique in GSM system, to further improve the performance of the conventional GSM system. The LC-EDAS technique independently search across signal and spatial dimension to eliminate the worse channel prior to transmission. Secondly, we investigate a sub-optimal low-complexity transmit antenna selection (LCTAS) in the GSM system to further reduce the computational complexity (CC) imposed by LC-EDAS. The Monte Carlo simulation results obtained reveals a trade-off between the GSM scheme with LC-EDAS and GSM scheme with sub-optimal transmit antenna selection in terms of error performance and CC.

ABSTRAK: Modulasi Spatial Keseluruhan (GSM) menghubung informasi kepada indeks kombinasi antena yang dipancarkan, membuatkan pemancaran keseluruhan simbol dapat dilakukan. Walau bagaimanapun, SM lebih bagus daripada skim GSM pada prestasi kesilapan pada kadar data yang sama, kerana kesan purata kuasa. Kepelbagaian penghantaran dan penerimaan ataupun kombinasi keduanya memberi pembaharuan yang lebih besar dalam sistem mimo pada prestasi kesalahan. Penyelidikan ini akan mengkaji optima terdekat Euclidean kurang rumit, melalui teknik (LC-EDAS) pilihan jarak antenna dalam sistem GSM, bagi menambah prestasi sistem GSM sedia ada. Teknik LC-EDAS secara sendiri mencari signal dan dimensi separa bagi mengurangkan saluran lebih teruk semasa penghantaran. Kedua, kami mengkaji sub-optima proses pemilihan kurang rumit penyebaran antena (LCTAS) dalam sistem GSM bagi mengurangkan kerumitan pengiraan (CC) yang dikenakan oleh LC-EDAS. Keputusan simulasi Monte Carlo yang diperoleh menunjukkan timbangan antara skim GSM dan LC-EDAS dan skim GSM bersama sub-optima proses pemilihan penyebaran antena berdasarkan kesilapan prestasi dan CC.