bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat Dissipation Through an Annular Disk or Fin of Uniform Thickness
Authors: Murray William MacGregor 
Published: February 2021

Abstract
The subject matter considered in this paper deals with the mathematical investigation of heat flow in an annular disk of uniform thickness. Originally, the investigation was carried on in connection with the design of fins for increasing the heat transfer in various kinds of heat exchangers and engines. The results of the study, however, might easily be applied to a number of other problems, since by altering the boundary conditions slightly one may use the same basic equations for calculating the temperature distribution and heat transmission in grinding wheels and disk clutches.
The study of the problem in connection with fin design has brought forth other solutions for special cases of the general proposition considered here. The particular results obtained by previous investigators can be readily found from the general equations given in this paper. In order to assist in the numerical solution of the somewhat complicated equations a chart for evaluating the mathematical expressions has been included.
Convective and Absolute Instabilities Induced by Viscous Dissipation in the Thermocapillary Convection With Through-Flow
Authors: Reis Eduardo V. M. , Alves Leonardo S. de B. 
Published: February 2021

Abstract
The mixed convection in a thin liquid film flow over a horizontal plate is investigated under finite Prandtl numbers. The gas–liquid interface is considered free, nondeformable and subject to surface tension gradients and convection, while gravity is assumed negligible. Therefore, thermocapillary instead of buoyancy effects appears due to the unstable temperature stratification induced by the internal heating generated by viscous dissipation. A linear and modal stability analysis of this model is then performed to identify its convective/absolute nature. This is achieved by solving the resulting differential eigenvalue problem with a shooting method. Longitudinal rolls are the most unstable at the onset of instability for most parametric conditions. Otherwise, transverse rolls are the first to become convectively unstable. Finally, longitudinal rolls are absolutely stable. A transition to absolute instability occurs through transverse rolls, but only within a limited region in parametric space.
Numerical Simulation of Heat Transfer in Laminar Natural Convection of Mixed Newtonian-Non-Newtonian and Pure Non-Newtonian Nanofluids in a Square Enclosure
Authors: Vallabh Ajay , Ghoshdastidar P. S. 
Published: February 2021

Abstract
This paper presents a steady-state heat transfer model for the natural convection of mixed Newtonian-Non-Newtonian (Alumina-water) and pure non-Newtonian (Alumina-0.5 wt% Carboxymethyl Cellulose (CMC)/water) nanofluids in a square enclosure with adiabatic horizontal walls and isothermal vertical walls, the left wall being hot and the right wall cold. In the first case, the nanofluid changes its Newtonian character to non-Newtonian past 2.78% volume fraction of the nanoparticles. In the second case, the base fluid itself is non-Newtonian and the nanofluid behaves as a pure non-Newtonian fluid. The power-law viscosity model has been adopted for the non-Newtonian nanofluids. A finite-difference based numerical study with the Stream function-Vorticity-Temperature formulation has been carried out. The homogeneous flow model has been used for modeling the nanofluids. The present results have been extensively validated with earlier works. In Case I, the results indicate that Alumina-water nanofluid shows 4% enhancement in heat transfer at 2.78% nanoparticle concentration. Following that there is a sharp decline in heat transfer with respect to that in base fluid for nanoparticle volume fractions equal to and greater than 3%. In Case II, Alumina-CMC/water nanofluid shows 17% deterioration in heat transfer with respect to that in base fluid at 1.5% nanoparticle concentration. An enhancement in heat transfer is observed for increase in hot wall temperature at a fixed volume fraction of nanoparticles, for both types of nanofluid.
Thermal Performance Comparison and Augmentation of Two Identical Box-Type Solar Cookers Operating in Tropical Climatic Conditions
Authors: Arif Md. Reyaz , Khan Mohammad Athar , Azhar Md. , Akhtar Naiem , Meraj Md. 
Published: February 2021

Abstract
In the present study, experimental studies have been performed to compare the thermal performance of two geometrically identical box type solar (B-T-S) cookers. To carry out this aim, the thermal performance of BTS cooker in terms of figure of merits, namely, first figure of merit (F1) and second figure of merit (F2) are calculated for both cookers as specified by the Bureau of Indian Standards (BIS). At no-load condition (i.e., stagnation test), it is found that first figure of merit for both cookers that is cooker 1 and cooker 2 is around 0.12. This implies that both the cookers are identical in thermal performance. In addition to this, the effect of lugs height, reflector, number of pots, and load on B-T-S cooker performance have also been investigated. From the results and discussion, it is concluded that the use of lugs reduced the heat transfer rate between cooking pot and absorber plate. Further, it is found that the pot content temperature is enhanced by 25.5% and 23.4% by using mirror and aluminum reflector with cooker, respectively. However, it is observed that the performance parameters of B-T-S cooker in terms of F2 increases linearly with the increase of number of cooking pot (with correlation F2 = 0.0316n + 0.2238, where n is the number of pots) and load (correlation as F2 = 0.0451 m + 0.1844, where m is the mass of water in cooking pot) on the pot.
Assessment of Heat Exchanger Degradation in a Boeing 737-800 Environmental Control System
Authors: Jennions Ian , Ali Fakhre 
Published: February 2021

Abstract
There are a number of systems on an aircraft working together, in harmony, to produce safe and trouble free flight. The environmental control system (ECS) is one of these systems, and its failure is a major contributor to unscheduled maintenance, particularly in older aircraft. The ECS is composed of several complex sub-systems and components, but at its heart is the passenger air conditioner (PACK). The PACK is prone to degradation, which can lead to the functional failure of the ECS. Often its degradation is masked by the overall ECS control system and this can, ultimately, result in the ECS shutting down and extensive maintenance being required. There are a number of critical fault modes associated with the PACK, and in this paper, those modes associated with the primary and secondary heat exchangers (SHX) are explored. A robust ECS simulation framework called Simscape ECS simulation under all conditions (SESAC) has previously been implemented, calibrated, and tested against data from healthy systems. Here the simulations are extended to cover degraded components in a representative Boeing 737-800 aircraft PACK model. Fault modes such as blockage and fouling are assessed for the primary and secondary heat exchangers of the PACK. Simulation results, in terms of temperature, pressure, and mass flow at various degradation severities, are presented and discussed. The results highlight the interdependency between the PACK components and the strong association between the primary and secondary heat exchangers performance. The reported simulation methodology and findings serve as a further step towards the goal of formulating a cost-effective ECS fault isolation and diagnostic solution.
Sub-Channel Analysis of a Hexagonal Sub-Assembly: Influence of Blockage and Axial Power Distribution on Critical Heat Flux
Authors: Pothukuchi Harish , Patnaik B. S. V. , Prasad B. V. S. S. S. 
Published: February 2021

AbstractThe study of thermal hydraulics of a hexagonal sub-assembly is essential to ensure the safe operation of liquid metal cooled fast reactors. Identifying the dryout location in fuel sub-assembly (FSA) is a precursor to the determination of safe Critical Heat Flux (CHF) margins. In this study, a sub-channel analysis code coupled with a film thickness model is employed to predict the CHF location in a hexagonal sub-assembly. A simple post-CHF heat transfer model is proposed and validated against the experimental data. The nature of flow resistance changes and operating conditions would significantly influence the occurrence of CHF. To this end, the effect of blockage (0.0 ≤ b ≤ 0.3) and axial power distribution (APD) on CHF is systematically investigated in a hexagonal sub-assembly. It was observed that the presence of blockage causes coolant flow maldistribution which results in an early occurrence of CHF for higher mass flux (G &gt; 1500 kgm−2s−1) and lower inlet subcooling (ΔTsub ≤ 30 K) conditions for b = 0.3. Furthermore, a comparative study of uniform and sinusoidal heat flux distributions is performed. It was noticed that sinusoidal APD causes the early occurrence of CHF compared to uniform APD.
Conjugate Heat Transfer Simulations to Evaluate the Effect of Anisotropic Thermal Conductivity on Overall Cooling Effectiveness
Authors: Bryant Carol E. , Rutledge James L. 
Published: February 2021

Abstract
Ceramic matrix composites (CMCs) show promise as higher temperature capable alternatives to traditional metallic components in gas turbine engine hot gas paths. However, CMC components will still require both internal and external cooling, such as film cooling. The overall cooling effectiveness is determined not only by the design of coolant flow, but also by the conduction through the materiel itself. CMCs have anisotropic thermal conductivity, giving rise to heat flow that differs somewhat relative to what we have come to expect from experience with traditional metallic components. Conjugate heat transfer computational fluid dynamics (CFD) simulations were performed in order to isolate the effect anisotropic thermal conductivity has on a cooling architecture consisting of both internal and external cooling. Results show the specific locations and unique effects of anisotropic thermal conduction on overall effectiveness. Thermal conductivity anisotropy is shown to have a significant effect on the resulting overall effectiveness. As CMCs begin to make their way into gas turbine engines, care must be taken to ensure that anisotropy is characterized properly and considered in the thermal analysis.
A Generalized Method for the Classification and Extraction of Form Features
Authors: Qamhiyah A. Z. , Venter R. D. , Benhabib B. 
Published: February 2021

Abstract
Feature-extraction techniques address the primary limitation of feature-recognition approaches, namely their lack of generalization. This paper presents a boundary-based procedure for the classification and sequential extraction of form features from the CAD models of objects with planar surfaces. Form features are first classified based on their effect on the boundary elements of a basic shape. Geometric reasoning is then used to obtain generalized properties of the form-features’ classes. Finally, form-features’ classes are sequentially extracted based on the recognized properties. At the onset of each extraction stage, the object is viewed as an initial basic shape that has been iteratively altered through the introduction of form features.
A Computer Environment for Realistic Assembly Design
Authors: Beach D. A. , Anderson D. C. 
Published: February 2021

Abstract
Described is an object-oriented assembly model that is formulated based on the needs of 3D graphical interaction, information needed for assemblability analysis, and principles of kinematics. The user interface provides real-time interaction with dual part representations, consisting of both feature and solid models, for building and modifying an assembly. Parts are moved and assembled in a realistic 3D environment. The system assists the user in creating attachments between parts in a “drag and drop” manner by dynamically displaying potential mating conditions based on location and alignment proximity.
Computer Controlled Integrated Steering / Drive System for Vehicles
Authors: Blair D. B. , Spark I. J. 
Published: February 2021

Abstract
This paper discusses how a computer controlled four-wheel-steering (4WS) system can be used to increase the ability, namely low speed stability and traction as well as increased manoeuvrability of four-wheel-drive (4WD) vehicles.
The essential feature of the integrated 4WS/4WD vehicle is that the path of the vehicle is selected via a joy stick or steering wheel, and a computer then controls the drive system of the two right hand wheels independently of the two left hand wheels, along with the positive rotation of the four wheels about vertical axes to the appropriate angles.
Previous work by Spark and Besselink (1994a) relating to two wheel steering (2WS) / two wheel drive (2WD) systems will also be discussed briefly and expanded.
Solution of Geometrically Nonlinear Problems Using Spatial Reference and the p-Version of the FEM
Authors: Noël Andre T. , Szabó Barna A. 
Published: February 2021

Abstract
This paper presents a new formulation for geometrically nonlinear problems and their numerical treatment by the p-version of the finite element method. The formulation is characterized by a weak form based on the spatial representation of the equilibrium equations, a deformed geometry mapped by the displacement field, a natural description for non-conservative loads that keeps the symmetry of the equations, and a direct (non-incremental) iterative algorithm for solving the equations. The paper is concerned only with problems for which the solution is unique, i.e. the load-displacement curves are single-valued. Examples are presented.
Finite Element Analysis of Automotive Structures Based on Simplified Models
Authors: Tang Xiaodong D. , Lu Chiming 
Published: February 2021

Abstract
This paper presents finite element analysis (FEA) of simplified automotive structures using beam-like elements. The concept is to perform FEA quickly or at early product development stage in order to guide the design process. Two types of finite element models are studied: 1) simplified models which use beam elements to model beam-like components and use other elements for the rest of the vehicle parts such as joints, engines and roofs; 2) thin-walled beam models which purely use thin-walled beam elements. The static stiffness, modal and crash analyses are conducted and the correlation of the results with those from conventional methods are provided.
The Geometry and Generation of NC Tool Paths
Authors: Sarma Radha , Dutta Debashish 
Published: February 2021

Abstract
Numerically controlled milling is the primary method for generating complex die surfaces. These complex surfaces are generated by a milling cutter which removes, material as it traces out pre-specified tool paths. The accuracy of generation of tool paths directly affects the accuracy of the manufactured part. For a given machine and cutting tool the cost of manufacture is directly dependent on the tool paths.
In this paper we propose a new method for generating NC tool paths. This method gives the part programmer direct control over the accuracy (scallop height) of the final surface and is capable of yielding a uniform surface finish. We also propose a new method for step-over calculations which is robust and accurate. The method also provides the part programmer options to generate a variety of tool paths.
Design of Modular Product Architectures in Discrete Design Spaces Subject to Life Cycle Issues
Authors: Rosen David W. 
Published: February 2021

Abstract
A product’s architecture affects the ability of a company to customize, assemble, service, and recycle the product. Much of the flexibility to address these issues is locked into the product’s design during the configuration design stage when the architecture is determined. The concepts of modules and modularity are central to the description of an architecture, where a module is a set of components that share some characteristic. Modularity is a measure of the correspondence between the modules of a product from different viewpoints, such as functionality and physical structure. The purpose of this paper is to investigate formal foundations for configuration design. Since product architectures are discrete structures, discrete mathematics, including set theory and combinatorics, is used for the investigation. A Product Module Reasoning System (PMRS) is developed to reason about sets of product architectures, to translate design requirements into constraints on these sets, to compare architecture modules from different viewpoints, and to directly enumerate all feasible modules without generate-and-test or heuristic search approaches. The PMRS is described mathematically and applied to the design of architectures for a hand-held tape recorder. Life cycle requirements are used as design criteria.
Augmented Reality Based Interaction: Application to Design and Manufacturing
Authors: Kesavadas T. 
Published: February 2021

Abstract
This paper presents applications of augmented reality-based interaction that allow new ways of interaction with manufacturing and design environments. The first example shows a design verification system in which a prototype virtual model of a template is blended into a manufacturing environment. The second part describes an interactive system for specifying robotic tasks using virtual tools that allow an operator to reach into a live video scene and direct robots to use corresponding real tools in complex scenarios. Such an interwoven AR system will allow easy and intuitive control of manufacturing tasks and will help designers to preempt design defects or faults and reduce the prototype development time.
Virtual Prototyping of Product Structure in Product Data Management
Authors: Menon Jai , Horn William 
Published: February 2021

Abstract
Product Data Management (PDM) systems are beginning to be deployed for organizing, accessing, and controlling data about products throughout their life cycle. In general, these systems lack integrated tools for prototyping PDM data, such as the Product Structure. Product Structure (PS) encompasses broadly the hierarchical organization of parts, typically denned by the bill of material, that describes the product from a variety of (e.g. design, manufacturing) views. Consistent maintenance and constant evaluation of the evolving PS is vital during iterative design, particularly when parts are shared across different products. The first contribution of this paper is a framework for understanding how PS/PDM fits within the broad context of mechanical design, leading to the identification of key desirables of PS prototypes. The second contribution is a system architecture for PS prototyping that satisfies these desirables. The system conveniently accesses different versions of the PS stored in the IBM ProductManager PDM system, and supports virtual prototyping of the PS using real-time interactive visualization in the IBM 3D Interaction Accelerator (3DIX) environment.
Virtual Prototyping: New Information Techniques in Product Design
Authors: Flaig Thomas , Thrainsson Magnus Thor 
Published: February 2021

Abstract
International competition is characterised by the reduce of the innovation time. Therefore the success of new products strongly depends on the necessary time for their development. Virtual Reality, a new 3D human-computer interface accelerates significantly the processes of creating and handling 3D data in 3D space for design and evaluation purposes. The paper outlines required system tools for the design and evaluation of new products based on Virtual Reality techniques. The goal of these tools is to enable interaction in an intuitive and easy way with a virtual product. Furthermore tools have been developed for the support of co-operative work in a virtual environment.
On the Design of Rapidly Deployable Field Robotic Systems
Authors: Farritor Shane , Dubowsky Steven , Rutman Nathan 
Published: February 2021

Abstract
Long development times and high costs limit the practical use of robots for many important field missions. Here the underlying hypotheses of a modular design approach to producing rapidly deployable, low cost field robotic systems are presented and their validity explored. An inventory of physical modules and software modules are assembled into a field robotic system for a specified task. The proposed design method uses a hierarchical selection process combined with a genetic algorithm to select a robot configuration and action plan for a given task. The method is applied to an inspection task required for the preservation of an historic ship.
Constraint Management Methodology for Conceptual Design Tradeoff Studies
Authors: Reddy Sudhakar Y. , Fertig Kenneth W. , Smith David E. 
Published: February 2021

Abstract
This paper presents a constraint management methodology, which facilitates tradeoff studies during conceptual design. This approach represents design models as constraints between variables, and uses the resulting constraint network to automatically derive computational procedures for performing user-specified tradeoff studies. By decomposing large constraint networks into smaller pieces that can be solved robustly, this approach can solve extremely large systems of non-linear equations present in practical system models. Design Sheet is a software implementation of this methodology; it allows the designer to interactively develop models, flexibly define tradeoff studies, and quickly explore large areas of design space to study how the different performance and cost criteria tradeoff with respect to one another. Design Sheet has been used on practical applications ranging from the system-level design of spacecraft using combined performance and cost models to the preliminary design of automotive bearings. This paper demonstrates the unique capabilities of Design Sheet in performing design tradeoff studies, using a thermal imaging system performance model developed for the DARPA MADE program.
Implications of Modularity on Product Design for the Life Cycle
Authors: Newcomb Patrick J. , Bras Bert , Rosen David W. 
Published: February 2021

Abstract
Growing concern for the environment has spurred interest in environmentally conscious design and manufacturing. The concept of Design for the Life Cycle encompasses all aspects of a product’s life cycle from initial conceptual design, through normal product use, to the eventual disposal of the product. A product’s architecture, determined during the configuration design stage, plays a large role in determining the product’s life cycle characteristics. In this paper, modularity of product architectures with respect to life cycle concerns, not just product functionality and structure, is defined and applied in the analysis of architecture characteristics. A principal hypothesis underlying this work is that high degree of life cycle modularity can be beneficial across all viewpoints of interest because all interested people will view the product similarly and consistently. An architecture decomposition algorithm from the literature is adopted for partitioning architectures into modules from each life cycle viewpoint. Two measures of modularity are proposed: one that measures module correspondence between several viewpoints, and another that measures coupling between modules. The algorithm and measures are applied to the analysis and redesign of an automotive center console. Results of applying the algorithm and measures accurately reflected our intuitive understanding of the original center console design and predicted the results of our redesign. Furthermore, these measures incorporate only configuration information of the product; hence, can be used before detailed design stages.