Main Process Steps Research Articles

Development of a sustainable product lifecycle in manufacturing firms: a case study

This study discusses a methodology for integrating Design for Environment (DfE) and life cycle assessment (LCA) techniques both into new product development and into the process of redesigning a set of existing products. The article explains the reasons for developing DfE in general, and pays particular attention to a specific, chosen product, a class of electrical distribution boards, to illustrate the concept. The main process steps in the development of the DfE are outlined, and the development of a LCA that satisfies the requirements of the ISO 14040 standard is illustrated. A major benefit of the DfE methodology proposed in this work is the possibility to use LCA data both during new product development and when modifying old products, with the aim of continuously reducing the overall environmental impact of products during their life cycle. This improvement cycle begins with the attempt to find new design solutions (for assembly and set-up in the case of electrical distribution boards), continues with the calculation of the enviromental break even point (BEP) and with the assessment of the BEP for the expenses incurred by the client. On the basis of these calculations and bearing in mind the technical specifications required by the clients and the work environment in which the product will be used, the designers will be able to make the most efficient choices from both the environmental and the economic point of view.

Energy Consumption and Net CO2 Sequestration of Aqueous Mineral Carbonation

Aqueous mineral carbonation is a potentially attractive sequestration technology to reduce CO2 emissions. The energy consumption of this technology, however, reduces the net amount of CO2 sequestered. Therefore, the energetic CO2 sequestration efficiency of aqueous mineral carbonation was studied in dependence of various process variables using either wollastonite (CaSiO3) or steel slag as feedstock. For wollastonite, the maximum energetic CO2 sequestration efficiency within the ranges of process conditions studied was 75% at 200 °C, 20 bar CO2, and a particle size of <38 μm. The main energy-consuming process steps were the grinding of the feedstock and the compression of the CO2 feed. At these process conditions, a significantly lower efficiency was determined for steel slag (69%), mainly because of the lower Ca content of the feedstock. The CO2 sequestration efficiency might be improved substantially for both types of feedstock by, e.g., reducing the amount of process water applied and further grinding of the feedstock. The calculated energetic efficiencies warrant a further assessment of the (energetic) feasibility of CO2 sequestration by aqueous mineral carbonation on the basis of a pilot-scale process.

Micro Semi‐solid Manufacturing ‐ A New Technological Approach towards Miniaturisation

One of the most important prerequisites to meet the increasing demand for efficient technologies for micro‐part production is constituted by the ability to overcome existing process limitations by new innovative technological approaches. By the introduction of a new process variant based on a hybrid material condition between solid and liquid state, such an approach is presented. This micro semi‐solid manufacturing technology, so‐called Micro‐Thixoforming, was initiated, on the one hand, by being aware of the technological limits of existing micro‐forming and micro‐casting processes and, on the other hand, by a comprehensive understanding of the special rheological mechanisms of metallic materials in semi‐solid state finally establishing the desired potential to follow the trend towards miniaturisation with drastically reduced process restrictions. However, this promising potential can only be successfully exploited when the initial idea, which is based on phenomenological considerations, can be transferred to a process technology with sufficient practical relevance. Therefore, the presented new integrated process concept for Micro‐Thixoforming is particularly characterised by the application of unconventional solutions for the main process steps: raw material conditioning, thermal pre‐processing, semi‐solid forming and thermal post‐processing. To give an indication of the innovative character of the chosen practical solutions liquid metal jet technology, LASER‐induced plasma shockwaves and high pressure water jet should be mentioned. However, what is even more important in this context is the ability not only to realise a process concept but, beyond that, to recognise the further potential regarding new strategies for material design arising from the availability of this process. Such a strategy e.g. consists of utilising the well‐known segregation effect, which notably often is negatively associated with semi‐solid forming. However, for the envisaged technological approach, controlled segregation aims at a defined adjustment of functionally graded properties for the produced micro part.

Cost of photochemical machining

Photochemical machining (PCM), also known as photoetching, photofabrication or photochemical milling, is a non-traditional manufacturing method based on the combination of photoresist imaging and chemical etching. PCM uses techniques similar to those employed for the production of printed circuit boards and silicon integrated circuits. The PCM industry plays a valuable worldwide role in the production of metal precision parts and decorative items. Parts produced by PCM are typically thin, flat, and complex. These parts have applications in electronics, mechanical engineering, and the aerospace industry. The increasing popularity of industrial applications, together with greater competition, means that there is a need to understand the costs involved in PCM so that the right technology can be selected for manufacturing. The paper identifies the costs involved in photochemical machining and presents a cost model for PCM using a bottom-up approach. The research used IDEF3 representation (work breakdown structure, WBS) to identify the process used in PCM. Expert interview, literature survey, and participant observation were used to identify cost drivers at each stage of the manufacturing process. The WBS and the cost drivers were used to develop the cost model, which is focused on stainless steel machining. Spreadsheets were used to implement the model, while the workbook is divided according to the main process steps and general costs. The worksheets contained in this workbook are: General Costs, Produce Drawing, Process Phototool, Select Metal, Prepare Metal, Coat the Metal, Process Photoresist, Etch Metal, Strip Photoresist, and Check and Package. Each of these sections is divided into the following types of costs: Materials, Direct Labour, Environmental and Indirect Costs. The workbook contains relevant data acquired from the PCM laboratory at Cranfield, PCM industry, and literature. The model is validated through expert judgement obtained on case study results. The model presented in this paper can be extended to include other PCM techniques to machine other materials.

Fabrication of capacitive ultrasonic transducers by a low temperature and fully surface-micromachined process

The fabrication of capacitive ultrasonic transducers by means of surface micromachining techniques and a low-temperature process is presented. Investigation of main process steps is reported. The use of polyimide as sacrificial layer, possible as the process is at low temperature, guarantees precise control of active transducer cells, thanks to its etching selectivity against the structural materials employed, and to the lithographic definition of the sacrificial layer into islands before the deposition of the membrane layer (pre-patterning). Control of the mechanical properties of free-standing membranes has been gained with the optimization of silicon nitride deposition and following thermal annealing steps. Transducers have been characterized by electrical impedance analysis, and their behavior agrees with theoretical modeling.

Successful Certification of an Environmental Product Declaration for an ABB Product

The article concerns the development and certification of an environmental product declaration, for a product produced by a company within the ABB Group. To date, the environmental management system ISO 14001 has been implemented in most of ABB's operational sites worldwide, i.e. in more than 600 units. ABB now takes the next step — to include its products in the scope of ISO environmental management standards, by developing environmental product declarations (EPDs), for all core products, hardware as well as services. The article points out the reasons for developing EPDs in general, and puts special focus upon a specific, chosen product, a class of rotating electrical machines, to illustrate the concept. The main process steps in the development of the EPD are outlined, including a description of background material required, and the role of defined product specific requirements (PSR). It also describes in general terms the development of a life cycle assessment that fulfills the demands of the ISO 14040 standard, and how to formulate an EPD that fulfills the demands of ISO TR 14025 that will be the future standard for type 3 environmental declarations. The contents of the EPD is described in general terms without providing concrete figures. The EPD described here is the first to be certified for any rotating electrical machine, worldwide.

Scale structure of aluminised Manet steel after HIP treatment

Coatings on low activation steels are required in fusion technology in order to reduce the tritium permeation rate through the steel into the cooling water system by a factor of at least 100. Alumina seems to be a promising coating material. However, an appropriate coating system must also have the potential for self-healing since the ceramic alumina scale tends to fail if mechanical stress is applied. A technology is introduced here to form a ductile Al enriched surface scale on Manet II steel (Fe-10.3%Cr) with an alumina overlayer. This technology consists of two main process steps. Hot dip aluminising has been performed at 700°C for 30 s in order to introduce Al to the near surface zone. The very hard intermetallic scale Fe 2Al 5 which forms during the immersion process gets completely transformed into FeAl 2, FeAl and α-Fe(Al) phases during a subsequent hot isostatic press (HIP) process step at high pressure at 1040°C for 30 min. The pressures chosen for the HIPing were 1000 and 2000 bar. Without HIPing pores form due to the Kirkendall effect. The influence of the high pressure on the heat treatment (1040°C, 30 min) will be discussed in this paper.

Scale structure of aluminised F82H-mod. steel after HIP treatment

Coatings on low activation steels are required in fusion technology in order to reduce the tritium permeation rate through the steel into the cooling water system by a factor of at least 100. Alumina seems to be a promising coating material. However, an appropriate coating system must also have the potential for self-healing since the ceramic alumina scale tends to fail if mechanical stress is applied. A technology is introduced to form a ductile Al enriched surface scale on F82H-mod steel (Fe-7.7% Cr) and on top of it alumina. This technology consists of two main process steps. Hot dip aluminising has been performed at 700°C for 30 s to the steel in order to introduce Al to the surface near zone by an easy way. The very hard intermetallic scale Fe 2Al 5 which forms during the immersion process gets completely transformed into FeAl 2, FeAl and α-Fe(Al) phases during a subsequent HIP process step at high pressure at 1040°C and 30 min. The pressure chosen for the HIP experiment was 3000 bar. Compared to a heat treatment without superimposed high pressure pores formation due to the Kirkendall effect could be suppressed successfully. The influence of the high pressure on the heat treatment (1040°C, 30 min) will be discussed in this paper.

Using a Common Information Model as a Methodological Basis for a Tool‐supported Requirements Management Process

AbstractThe growing complexity of systems and the continuing pressure on reductions in development time and cost can only be tackled if an effective and tool‐supported requirement management process is established. In our view, requirements management is not just part of requirements engineering. Instead, in principle, it is part of all phases of the entire system life‐cycle, ranging from market analysis and top‐level customer requirements to system maintenance, final shutdown, and removal. In this paper, we report on some methodological experiences gained from introducing a tool‐supported requirements management process at DaimlerChrysler Aerospace Airbus. First, we will describe our view of the main process steps in requirements management and the typical roles that people play in a tool‐supported requirements management process. Then, we will introduce the basic parts of a common requirements management information model and discuss how a general common information model helps to support the main process steps in requirements management.

Process Development for Continuous Crystalization and Separation of Fat Crystal Suspensions

The industrial use of fat fractions increases with the possibilities to produce fractions with specific chemical and physical properties. Dry fractionation consists of two main process steps: crystallization of a triglyceride fraction and its subsequent separation. During crystallization a part of the triglycerides contained in the fat, which is crystallized from the melt by supercooling.

Process Development for Continuous Crystalization and Separation of Fat Crystal Suspensions

The industrial use of fat fractions increases with the possibilities to produce fractions with specific chemical and physical properties. Dry fractionation consists of two main process steps: crystallization of a triglyceride fraction and its subsequent separation. During crystallization a part of the triglycerides contained in the fat, which is crystallized from the melt by supercooling.

Design of a solvent extraction process for PAH-contaminated sediments: the wau-acetone process

Solvent extraction is one of the possibilities to clean-up polluted sediments. It is especially attractive when the sediment mainly consists of clay particles polluted with contaminants which are not, or not easily, biodegradable. Using acetone as extracting agent the extraction process has been investigated at laboratory scale for treating sediment of the Petroleum Harbour in Amsterdam. This sediment is characterised by a substantial percentage of particles with diameter &amp;lt;63 μm, a high percentage of organic matter (about 12% on dry matter basis), a high concentration of PAH (500-2,000 mg total EPA-PAH per kg dry matter) and a high concentration of mineral oil (6,000–10,000 mg/kg dry matter). Based on the laboratory scale experiments a process design has been made of a complete solvent-extraction process with acetone. The main process steps in this design consist of a countercurrent flow extractor, a separator for the sediment, a post-treatment step to remove residual acetone from the sediment, a distillation column to recover the acetone for reuse and to concentrate the pollutants and a polishing step for the water to be discharged. The sediment treatment costs with this system are estimated at 115 NGL per tonne dry matter to be treated.

Design of a solvent extraction process for PAH-contaminated sediments: The wau-acetone process

Solvent extraction is one of the possibilities to clean-up polluted sediments. It is especially attractive when the sediment mainly consists of clay particles polluted with contaminants which are not, or not easily, biodegradable. Using acetone as extracting agent the extraction process has been investigated at laboratory scale for treating sediment of the Petroleum Harbour in Amsterdam. This sediment is characterised by a substantial percentage of particles with diameter < 63 μm, a high percentage of organic matter (about 12% on dry matter basis), a high concentration of PAH (500–2,000 mg total EPA-PAH per kg dry matter) and a high concentration of mineral oil (6,000–10,000 mg/kg dry matter). Based on the laboratory scale experiments a process design has been made of a complete solvent-extraction process with acetone. The main process steps in this design consist of a countercurrent flow extractor, a separator for the sediment, a post-treatment step to remove residual acetone from the sediment, a distillation column to recover the acetone for reuse and to concentrate the pollutants and a polishing step for the water to be discharged. The sediment treatment costs with this system are estimated at 115 NGL per tonne dry matter to be treated.

Regeneration of loaded supercritical fluids

In a closed-cycle production plant utilizing the properties of supercritical gases, regeneration of the solute-supercritical fluid mixture is one of the two main process steps. Even though regeneration has been investigated, no systematic research has been done on the topic. In this paper, results of research activities that were performed in the last three years in Hamburg are presented. 1 Different methods for regeneration were chosen to examine the ability of each to separate a solute-supercritical fluid mixture: pressure and temperature change, adsorption, absorption, membranes, and a new method called deentrainment. Three different solutes were chosen to be separated from the supercritical fluid. New data for caffeine are presented that include caffeine-CO 2 phase equilibria for pressures below 20 MPa, caffeine-water-CO 2 phase equilibria, caffeine-activated carbon-CO 2 phase equilibria and tocochromanol-ethanol-water-CO 2 phase equilibria. Mass transport phenomena are considered to play an important role in the separator. The base of experimental data was used together with literature data to establish an evaluation system for the regeneration of supercritical fluids. This was done using membership functions μ( x) that are known in fuzzy-sets to establish the regeneration ability of a method for a certain parameter x ( x: solute properties, thermodynamic conditions, operating parameters). A complete system of graphic functions are shown that allows the evaluation of the different methods according to a given case.

Three-dimensional process simulation

Within the JESSI/ESPRIT project PROMPT, a program system for the multidimensional simulation of semiconductor fabrication steps is being developed. The overall goal is to provide appropriate information on the three-dimensional device geometry and dopant distributions as input to three-dimensional device simulation. For this purpose, both existing one- and two-dimensional process simulation programs and newly developed three-dimensional simulation modules are being used. In addition to the general concept of the PROMPT system, a brief description of the approaches used for the three-dimensional simulation of the main process steps is given.

96/06594 Disposal of weapon plutonium: Approaches and prospects

Preface. Session I: Safe Disposal of Weapons Plutonium. 1. Weapons Plutonium Management: The Present Situation, the Methods and the Prospects A.I. Karelin. 2. Retrievability and Safeguards Concerns Regarding Plutonium in Geological Repositories J. Swahn. 3. Multibarriers: Their Efficacy Against Intentional Intrusion into a Geological Repository to Retrieve Disposed Plutonium E.R. Merz. 4. Prospects for Using Plutonium as a Fuel in Russia V.N. Mikhailov, et al. 5. Plutonium Handling and Vitrification: Main Process Steps and their Cost Evaluation E. Trauwert, M. Demonie. Session 2: Product Forms. 6. Dissolution of Materials Containing Metal Plutonium and Oxidized Forms of Plutonium G.P. Nikitina, et al. 7. Crystalline Ceramics: Waste Forms for the Disposal of Weapons Plutonium R.C. Ewing, et al. 8. The Crystalline Host-Phases for Immobilization of Weapons Plutonium and Waste Actinides B.E. Burakov, et al. 9. On the Long-Term Storage of Weapons Plutonium in Form of Criticality-Free Ceramics Containing Lithium J.A. Trutnev, et al. 10. Incorporation of Pu and other Actinides in Borosilicate Glass and in Waste Ceramics Hj. Matzke, J. van Geel. 11. Feasibility of Rock-Like Fuel and Glass Waste Forms for Disposal of Weapons Plutonium H. Furuya, et al. 12. Possible Ways of the Weapon Plutonium Processing to Produce the Steady Glass Materials Suitable for Further Safe Disposal Y.I. Matyunin, et al. 13. Management of Operational Waste from MOX Fuel Plants F.W. Ledebrink. Session 3: Vitrification Technology. 14. SRS Vitrification Studies in Support of the U.S. Program for Disposition of Excess Plutonium G.G. Wicks, et al. 15. On the Feasibility of Vitrifying High-Level Liquid Waste Containing High Amounts of Plutonium M. Demonie, H. Cuyvers. 16. Vitrification of Weapons Plutonium: A Hypothetic Option or a Real Way to Solve the Problem A.S. Aloy, E.B. Anderson. 17. Vitrification of Plutonium for Disposal J.A.C. Marples. 18. French Appraisal of the Vitrification Option. Weapons Plutonium -- or how to get rid of it! A. Jouan. 19. Safety Aspects with Regard to Plutonium Vitrification Techniques L.W. Gray, T. Kan. Session 4: Disposal in Deep Boreholes. 20. Disposition of Radionuclides in Deep Geological Formations either in Containers or Vitrified Form T.A. Goupalo. 21. Disposition of Plutonium in Deep Boreholes W.H. Halsey, et al. Session 5: Long Term Safety Aspects. 22. The Process of the Equipment and Room Surface Pu- Decontamination and Means to Prevent their Contamination A.B. Pavlov, Ye.I. Yulikov. 23. Technical Basis for Pu Safeguard Practices, Handling and Disposal, PERLA and TAME Experiences H. Dworschak. 24. Long-Term Safety Aspects of Geological Disposal of Large Quantities of Plutonium B. Baltes. 25. MPC&A for Plutonium Disposition in the Russian Federation W.G. Sutcliffe. 26. Ecological Safety Aspects with Regard to Plutonium Disposal V.F. Menschikov. 6. Summary of Workshop Presentations. 7. NATO Workshop Summary evaluation. Index.

Tritium Recovery from a Solid Breeder Demo Blanket

The main task of a Tritium Extraction System (TES) for a helium cooled Li{sub 4}SiO{sub 4} DEMO blanket is the tritium recovery from a purge gas stream. On the basis of several TES proposals published for a NET/ITER solid breeder blanket, a new concept has been developed which is especially appropriate to cope with large purge gas streams. As tritium is expected to appear in two chemical forms (HT and HTO) two specific process steps are used for its removal from the primary purge gas loop: a cooler to freeze out Q{sub 2}O at 173 K (Q = H,T), and a molecular sieve bed to absorb Q{sub 2} at 78 K. Only these components including some additional devices for the gas pre-conditioning like a compressor and a precooler, are subjected to the high gas flow rates mentioned above. All further processing is done in relatively small secondary loops during and after warmup of the cooler and the molecular sieve bed. Q{sub 2}O reduction by using the water gas shift reaction, and separation of Q{sub 2} with Pd/Ag diffusors are the main process steps in the secondary loops. The feasibility of the proposed method is very promising as all process stepsmore » are based on well known technical and radiochemical experience. 20 refs., 4 figs., 1 tab.« less

Innovative Extrusion Systems for Advanced Fiber and Film Extrusion

Abstract Advanced fiber and film extrusion is a term used to describe high speed spinning of low denier filaments and stretching of thin films at high output rates and high efficiencies. Using the advantages of separated process steps, extrusion systems have been developed in which the main process steps, such as feeding, melting, homogenizing, filtering, mixing and metering, take place in special separate equipment aggregates. In comparison to standard extruders with combined process steps, these extrusion systems give better melt quality as measured by the uniformity of melt flow, drawability of the fibers or films and the dispersion of additives. Examples of extrusion systems for PET or PP with appropriate operating conditions and output rates are described. The different applications of these systems and their main details are listed in a survey.

A minimum step fabrication process for the all-silicon channeling mask

In this paper the all‐silicon channeling mask is described and its advantages for masked ion beam lithography (MIBL) applications are discussed. A minimum step process for fabricating the all‐silicon mask is presented in detail. The main process steps include epitaxial growth of silicon, membrane etching, and high resolution magnetron ion etching. Experimental parameters and fabrication results are presented.