Computer-aided Design Process Research Articles

Construction of a Knowledge Base for Ergonomic Design with Human Models

In order to economically evaluate products and workplaces from the early stage of design, it is essential to provide the designer with a variety of design and evaluation means. In Korea, incorporation of ergonomic design and evaluation into the computer-aided design process of product development in industry has been in great need. A number of ergonomic design models have been developed and are currently in use. Evaluation functions embedded in those models are, however, based mostly on predictive algorithms such as reach and visibility tests, whereas numerous ergonomic guidelines which constitute a major part of design knowledge have been rarely accommodated to such models. In this research, a knowledge base was constructed to expand the scope of ergonomic evaluation being made through those models. First, a new framework based on an object-oriented database for the model was suggested from the developer's standpoint. Second, the knowledge modeling was done based on the definition through the object-oriented database. Finally, the knowledge base was implemented in the prototype design model that enables to evaluate design alternatives, interactively. It is expected that the knowledge base proposed would lessen the burden of designers through efficient evaluations from the early stage of design.

Computer-aided process design using Food Operations Oriented Design System Block Library

The comparison of design alternatives is a common design task for food process engineers. Foods Operations Oriented Design System Block Library (FOODS-LIB ©) in conjunction with its economic analysis program (ECONANAL) can be used in this capacity. To demonstrate how FOODS-LIB can be used in a time efficient manner to perform analysis of design alternatives, a case study was conducted in which five alternative processes to manufacture whole milk powder were compared. The design goal was to minimize steam use and maximize 10 yr net present worth.

Computer-Aided Process Design for Tension Levelling of Clad Sheet Metal

Computer-Aided Process Design for Tension Levelling of Clad Sheet Metal

Fundamental questions in optimizing ion-exchange chromatography of proteins using computer-aided process design

The major objectives for preparative protein chromatography are maximal loading and increased flow rate while maintaining defined resolution. Conventionally a series of chromatographic experiments are performed and the optimal conditions are selected according to the separation criteria. Computer-aided process design uses the same strategy, except a group of related experiments are generated by computer simulation. The access to concrete separation parameters for valid simulation necessitates chromatographic experiments. Optimal conditions are determined in the same manner as conducted in the conventional strategy. Beside other parameters, the distribution coefficient (K) determines the performance of a chromatographic purification under overloading conditions. In ion-exchange chromatography the distribution coefficient is strongly influenced by the protein concentration (C) and the salt concentration (I). A strategy to derive the distribution coefficient from chromatographic experiments, such as isocratic runs (pulse response), linear gradients, and frontal analysis, is described and compared to previously published strategies. In ion-exchange chromatography, the number of plates and transfer units change with the salt concentration. The distribution coefficient for salt also changes under various conditions including salt and protein concentration. The number of plates and transfer units also vary with the flow rate. Furthermore criteria such as the multicomponent situation require a more complex mathematical treatment. Several solutions have been validated to circumvent those obstacles.

Rapid Prototyping of Patterned Multifunctional Nanostructures

AbstractThe ability to engineer ordered arrays of objects on multiple length scales has potential for applications such as microelectronics, sensors, wave guides, and photonic lattices with tunable band gaps. Since the invention of surfactant templated mesoporous sieves in 1992, great progress has been made in controlling different mesophases in the form of powders, particles, fibers, and films. To date, although there have been several reports of patterned mesostructures, materials prepared have been limited to metal oxides with no specific functionality. For many of the envisioned applications of hierarchical materials in micro-systems, sensors, waveguides, photonics, and electronics, it is necessary to define both form and function on several length scales. In addition, the patterning strategies utilized so far require hours or even days for completion. Such slow processes are inherently difficult to implement in commercial environments. We present a series of new methods of producing patterns within seconds. Combining sol-gel chemistry, Evaporation-Induced Self-Assembly (EISA), and rapid prototyping techniques like pen lithography, ink-jet printing, and dip-coating on micro-contact printed substrates, we form hierarchically organized silica structures that exhibit order and function on multiple scales: on the molecular scale, functional organic moieties are positioned on pore surfaces, on the mesoscale, mono-sized pores are organized into 1-, 2-, or 3-dimensional networks, providing size-selective accessibility from the gas or liquid phase, and on the macroscale, 2-dimensional arrays and fluidic or photonic systems may be defined. These rapid patterning techniques establish for the first time a link between computer-aided design and rapid processing of self-assembled nanostructures.

Rapid Prototyping of Patterned Multifunctional Nanostructures

ABSTRACTThe ability to engineer ordered arrays of objects on multiple length scales has potential for applications such as microelectronics, sensors, wave guides, and photonic lattices with tunable band gaps. Since the invention of surfactant templated mesoporous sieves in 1992, great progress has been made in controlling different mesophases in the form of powders, particles, fibers, and films. To date, although there have been several reports of patterned mesostructures, materials prepared have been limited to metal oxides with no specific functionality. For many of the envisioned applications of hierarchical materials in micro-systems, sensors, waveguides, photonics, and electronics, it is necessary to define both form and function on several length scales. In addition, the patterning strategies utilized so far require hours or even days for completion. Such slowprocesses are inherently difficult to implement in commercial environments. We present a series of new methods of producing patterns within seconds. Combining sol-gel chemistry, Evaporation-Induced Self-Assembly (EISA), and rapid prototyping techniques like pen lithography, ink-jet printing, and dip-coating on micro-contact printed substrates, we form hierarchically organized silica structures that exhibit order and function on multiple scales: on the molecular scale, functional organic moieties are positioned on pore surfaces, on the mesoscale, mono-sized pores are organized into 1-, 2-, or 3-dimensional networks, providing size-selective accessibility from the gas or liquid phase, and on the macroscale, 2-dimensional arrays and fluidic or photonic systems may be defined. These rapid patterning techniques establish for the first time a link between computer-aided design and rapid processing of self-assembled nanostructures

Computer aided process design in cold-former forging using a forging simulator and a commercial CAD software

In this paper, a computer aided process design technique, based on a forging simulator and commercial CAD software, is presented together with its related design system for the cold-former forging of ball joints. The forging sequence design and its detail designs are generated through user–computer interaction using templates, design databases, knowledge-based rules and some basic laws. The forging simulation technique is used to verify the process design. The detail designs, including die set drawings and die manufacturing information, are generated automatically. It has been shown that engineering and design productivity is much improved by the presented approach from the practical standpoint of process design engineers.

New polarized electromagnetic actuators as integrated mechatronic components — design and application

This paper presents an overview over the computer-aided design process of mechatronic devices and systems, especially the design of electrodynamic and electromagnetic drives using modern high-energy permanent magnetic materials like NdFeB and SmCo. This paper also presents some examples of such actuators. The first example is a miniaturized pneumatic valve for industrial applications. This valve has an integrated bi-stable polarized solenoid actuator. The second example is a polarized electromagnetic valve manufactured by modern batch technologies using photo-structurable glass material. The valve seat and the actuator coils are realized using this glass material. The third example is a gripping device with compliant mechanism and planar moving coil actuator.

An Introduction to Geographical Information Systems

Beginning with the discussion of what is GIS, this article explains the concept of geographical data and spatial data models. Two software systems, viz computer-aided design and image processing have been identified as the close relatives of GIS and the similarities and differences between these systems and GIS are described. The operational functions of GIS are described under the categories of data input, analysis, spatial query and data output. Various application areas of GIS alongwith specialized applications of GIS are discussed. Some of the GIS software packages have been mentioned. A brief view has been taken of the state of GIS in India and the article is concluded.

Computer-aided process design for the tension levelling of metallic strips

Abstract The present paper deals with a computer-aided process design for tension leveling based on finite element analysis. A FE code developed specifically for that purpose, which involves a sophisticated constitutive model of cyclic plasticity, enables the accurate performing of a numerical simulation. The very short computation time in numerical simulation by this FE code is due to a novel calculation algorithm to solve the steady elasto-plasticity problem based on the incremental deformation theory of plasticity. From the results of numerical simulation for some tension leveling processes, it has been concluded that a series of work rolls should be set in the final stage of the leveling process such that the roll-intermesh gradually decreases along the stream line and approaches zero at the final roll.

Implementation of rapid Prototyping technology ? A Hong Kong manufacturing industry's perspective

Rapid Prototyping (RP) is a technology for rapid computerised building of 3D physical parts. It can be defined as an automated and patternless process which allows solid physical parts to be made directly from computer data in a short time. RP acts as the “manufacturing middle” to link up the computer-aided design (CAD) process and manufacturing processes. It includes the making of prototypes for design verification and even the making of tooling for production. With the trend towards concurrent engineering and the widespread use of CAD, RP has quickly become a booming business in the past few years. This paper presents an overview of the implementation of RP technology in Hong Kong and the critical decision factors in implementing RP in the Hong Kong manufacturing industry.

A study of a computer-aided process design system for axisymmetric deep-drawing products

A computer-aided process design system for axisymmetric deep drawing products has been developed. An approach to the CAD system is based on a knowledge-based system, the knowledge for the CAS system being formulated from plasticity theories, handbooks, experimental results and the empirical knowledge of field experts. The CAD system has been written in AutoLISP on the AutoCAD system with a personal computer. The CAD system is composed of four main modules, which are input, geometrical design, test and rectification and user modification. The input to the system is the drawing of the final sheet-metal object geometry and the output from the system is the drawing of process sequence with intermediate object geometry and the drawing of the process parameters, such as the drawing load, the blank-holding force, the clearance and the cup-drawing coefficients. The developed CAD system will aid designers by providing powerful capabilities for the process design of axisymmetric deep-drawing products.

Towards a computer-aided architectural design process: a journey of several mirages

This paper discusses the history and current state of development of the application of computers to architectural design. The process of trying to develop useful roles for the computer in the design process is seen as a yet unfinished journey. As we travel, we simultaneously develop more understanding of the design process and acquire more sophisticated computer technology. The promise and potential for the computer in architectural design has thus shifted rather than remained a constant target. Over the years, we have seen the computer as designer, draftsman, modeller, evaluator, and assistant. The paper shows how none of these roles have yet been satisfactorily realised in relation to the potential which the computer appears to have. In particular, the paper shows that this is due to a misunderstanding of the real nature of the architectural design process. The paper finishes with some suggestions for a new research agenda for the field.

Computer-aided process design and optimization with novel separation units

This paper reports the results from the application of various methodologies to generate and analyse process flowsheets with novel separation units. Novel separation processes in this paper include supercritical extraction (SCE), melt crystallization (MC) and gas adsorption (GA). Application of a newly developed process synthesis technique has allowed the identification of processes where mixtures to be separated show azeotropic behaviour and, therefore, are candidates for a SCE-based process. Design and optimization studies have revealed the feasibility of ‘pressure-swing’ distillation as well as SCE-based separation as promising alternatives for these separations. In the case of MC, processes requiring separation/purification of compounds having specified limits of viscosity and melting point have been identified as candidates for MC-based separation. In the case of GA, a knowledge-based analysis is currently being developed for identification of potential candidate adsorbents and the corresponding gas-separation systems. Melt crystallization could be identified as a substitute for distillation in acrylic acid production. In acrylic acid production distillation resulted in an energy demand of 2.659 × 10 6 kJ/ton acrylic acid. Six different cases of incorporation of melt crystallization as a partial or total substitute for distillation were analysed, and melt crystallization gave energy reductions in the range from 7.7 × 10 4 to 1.86 × 10 6 kJ/ton acrylic acid. In a phenol production plant [9], the energy consumption may be reduced from 8.68 × 10 6 kJ/ton phenol to 8.00 × 10 6 kJ/ton phenol by employing melt crystallization as a substitute for distillation. For methylacetate production, novel separation schemes reduce the energy costs 1.4 times compared to the conventional separation schemes [9].

A Platform Neutral Computer Aided Control Engineering Environment

This paper proposes a computer aided control systems design environment based on an object-oriented component model. A document centered approach towards the process of computer-aided control systems design is taken. This paper examines current technologies for realizing such an environment which may be used platform neutrally, collaboratively and over a network.

Computer-aided electrochemical process design: simulation and economic analysis of an electrocatalytic soybean oil hydrogenation plant

The process flowsheet for a soybean oil electrohydrogenation plant has been devised and heat and mass balance calculations on unit operations equipment were performed using a commercially available process simulation software package (PRO/II from Simulation Sciences, Inc.). The design and anticipated performance (current efficiency and power requirements) of the electrochemical flow cells were based on a laboratory-scale radial-flow-through Raney nickel powder electrocatalytic hydrogenation reactor. A semiempirical porous electrode model, that reproduced laboratory-scale reactor data, was incorporated into the PRO/II software as a unit operations subroutine module. Operation of a 3.0×106kgy−1 electrochemical plant was simulated on a computer for different soybean oil/electrolyte feeds and reactor current densities. Based on the PRO/II results, an economic analysis of the process, including capital, installation and operating costs of all equipment was carried out. The lowest total production cost for a brush hydrogenation oil product (20% reduction in the number of double bonds) was obtained at a current density of 15mAcm−2 and a feed composition of 10wt:vol% soybean oil in solvent/supporting electrolyte (US0.13kg−1 for an assumed five year straight line depreciation of capital equipment). This cost was higher than that for a comparable-size chemical catalytic soybean oil hydrogenation plant (US0.019kg−1). When the cost of the soybean oil starting material (US0.68kg−1) was factored into the economic analysis, the production plus raw material cost of the electrocatalytic process was only 16% greater than that for the chemical catalytic plant. The production cost for the electrosynthesized hydro-oil product may be tolerable because the oil has a high nutritional value (a lower trans isomers content) which may command a higher selling price.

Preservation Factors in the Appraisal of Architectural Records

The assessment of physical formats, condition, and preservation needs is an essential part of the appraisal of architectural records. The first step in the preservation appraisal process is to identify the physical process represented in an item. It is then necessary to determine whether it has intrinsic or artifactual value, and its informational value. In addition, because diazo prints and Vandyke negative prints are the architectural equivalents of brittle paper, it is also important to survey the condition of the materials in a collection. Finally, the size of the materials, which tend to be large in architectural records, and which will determine the storage spaces and conservation treatment spaces necessary to properly handle them, needs to be assessed. The preservation of architectural records has been complicated by the development of computer-aided design and other digital processes. It remains to be seen, however, whether digitization of architectural processes provides more solutions or problems to preservation concerns.

Computer aided process design: Short-cut design for polymer production

An hierarchical procedure for the conceptual design and rapid simulation of free radical homo- and copolymerisations in solution is presented. This conceptual design procedure is intended for use as a tool for the understanding and screening of design alternatives, especially by the inexperienced user. It uses the minimum amount of information possible to screen a large series of process alternatives in order to identify potentially optimal process designs, both in terms of economics and product quality (polymer molecular weight, etc.), and to eliminate alternatives that are either physically undesirable or economically unfeasible. Additionally, the computerised version of the programme can be used to perform a sensitivity analysis of candidate designs this procedure allows the user to see what are the most important parameters to be considered, what can be ignored, and where future experimental programmes would be most beneficial. Examples of the production of both homo- and copolymers in solution are presented.

Computer-aided process design: The design of an affinity-based continuous separation process

The exploration and design of novel processes and modified process configurations can be improved by process simulation. The development of an adequate process model, however, is the crucial step. When the development of a rigorous model is hindered by the lack of fundamental data a different approach has to be taken. Such an approach is described for a continuous biospecific adsorption process. A method for the analysis of fixed bed breakthrough data was developed and tested. Models for batch and continuous separation processes were built, based on the variation of the analysis parameters. The deduced models could be verified against fixed bed and continuous adsorption experiments. Simulation studies were conducted to assess the optimal process configuration with regard to the product purity and the controllability of the process. Furthermore comparisons of batch and continuous adsorption processes with respect to adsorbent and utility consumption were carried out.

Color Stereophotolithography: A Method of 3-D Color Imaging

3-D color stereophotolithography is based on the classic laser stereophoto-lithography technique, but it needs several reactors containing colored resins instead of just one containing a commercial resin. By moving the incident laser beam in each reactor for each color, one can create color parts of very fine quality. This could be applied to the manufacture of 3-D color objects conceived in the computer-aided design process. This new technique should be very attractive in fine arts, architecture, etc.