Analiza pristupačnosti strana u svrhu projektiranja modularnih naprava

This paper describes the methodology for the identification of accessibility of faces of 3D model of the workpiece, for the purpose of its positioning and clamping, by use of developed software application. Software application is developed in SolidWorks environment with the purpose to design modular fixtures. Using the SolidWorks API, MS Excel, object-oriented programming language Visual Basic 6 and logic in the form of production rules and algorithms, the development of software application was executed. Identification of the accessibility of faces of 3D model of the workpiece is based on the identification of characteristic coefficients and generation of their values. The coefficient of accessibility of faces appears as a final result of conducted analysis of face`s accessibility of the 3D model workpiece. The results gained from this software application are used to generate points for the positioning and clamping in the process of modular fixtures design. Developed software application provides mathematical notation of the face`s accessibility for the adopted conditions and restrictions, which was verified on the particular workpiece.Ovaj rad opisuje postupak za identificiranje pristupačnosti strana 3D modela radnog komada, u svrhu njegovog pozicioniranja i stezanja, korištenjem razvijene programske aplikacije. Programska aplikacija je razvijena u SolidWorks okružju u svrhu projektiranja modularnih naprava. Korištenjem SolidWorks API, MS Excel, objektno orijentiranog programskog jezika Visual Basic 6 i logike u obliku produkcijskih pravila i algoritama, izvršen je razvoj programske aplikacije. Identifikacija pristupačnosti strana 3D modela radnog komada bazira se na identifikaciji karakterističnih koeficijenata i generiranja njihovih vrijednosti. Koeficijent pristupačnosti strane se pojavljuje kao krajnji rezultat provedene analize pristupačnosti strane 3D modela radnog komada. Rezultati iz ove programske aplikacije koriste se za generiranje točaka za pozicioniranje i stezanje u procesu projektiranja modularnih naprava. Razvijena programska aplikacija daje matematički zapis pristupačnosti strane za usvojene uvjete i ograničenja, što je verificirano na konkretnom radnom predmetu

Mobility of bodies in contact. II. How forces are generated bycurvature effects

For part I, see ibid., p.696-708. The paper considers how forces are produced by compliance and surface curvature effects in systems where an object a is kinematically immobilized to second-order by finger bodies Al,...,Ak. A class of configuration-space based elastic deformation models is introduced. Using these elastic deformation models, it is shown that any object which is kinematically immobilized to first or second-order is also dynamically locally asymptotically stable with respect to perturbations. Moreover, it is shown that for preloaded grasps kinematic immobility implies that the stiffness matrix of the grasp is positive definite. The stability result provides physical justification for using second-order effects for purposes of immobilization in practical applications. Simulations illustrate the concepts

A Feasibility Investigation of Modular Portable “Chelson Shelters” Micro-Homes to Alleviate Housing Deficiencies: A Case Study in Mithi, Tharpakar, Pakistan

Many people in Mithi, Tharparkar do not have proper housing, face an unhygienic water supply, and have no sanitation facilities. These factors contribute to disease, suffering and the inability to rise above their destitute existence. The idea for building portable houses for the people of Mithi is presented to provide them with better living conditions and where they can feel a sense of security, ownership and sanitation. Research on existing building systems and materials showed that the most feasible structure for the desert environment is modular panels attached to a core unit that contains all the basic plumbing and electrical fixtures. The unit can be expanded based on family needs. Discussion with government officials showed that these could be used for the immediate needs of the people who have been suffering more acutely the last several years due to a drought. They could also be a permanent solution to the housing crisis if the Chelson Shelter communities worked well for ten years. The infrastructure in the Tharparker Desert is inadequate to support typical housing. These shelters have low environmental impact, use little water and electricity and would be a good solution to make a community of people that can support each other and provide security

Tinkertoys for the Twisted D-Series

We study 4D N=2 superconformal field theories that arise from the compactification of 6D N=(2,0) theories of type D_N on a Riemann surface, in the presence of punctures twisted by a Z_2 outer automorphism. Unlike the untwisted case, the family of SCFTs is in general parametrized, not by M_{g,n}, but by a branched cover thereof. The classification of these SCFTs is carried out explicitly in the case of the D_4 theory, in terms of three-punctured spheres and cylinders, and we provide tables of properties of twisted punctures for the D_5 and D_6 theories. We find realizations of Spin(8) and Spin(7) gauge theories with matter in all combinations of vector and spinor representations with vanishing beta-function, as well as Sp(3) gauge theories with matter in the 3-index traceless antisymmetric representation.Comment: 75 pages, 270 figure

Genus-gg, nn-point, bb-boundary, cc-crosscap correlation functions of two-dimensional conformal field theory: Definition and general properties

We propose a systematic definition of genus-$g$, $n$-point, $b$-boundary, $c$-crosscap correlation functions $\mathcal{F}_{g,n,b,c}^{x}$ with $x$ boundary operators, for general two-dimensional conformal field theory. The $\mathcal{F}_{g,n,b,c}^{x}$ are defined as the inner products of the surface states with the tensor product of $n$ asymptotic states, $b$ boundary states and $c$ crosscap states, where the $b$ defining boundary states carry a total of $x$ boundary operators. The definition implies that $\mathcal{F}_{g,n,b,c}^{x}$ are infinite linear combinations of genus-$g$, $(n+b+c)$-point functions $\mathcal{F}_{g,(n+b+c)}$. A single pole structure is identified in the expansion coefficients $\mathcal{F}_{g,n,b,c}^{0}$, which is analogous to the single pole structure in the conformal block decomposition. This linear property unifies boundary and bulk CFTs. The consistency conditions of $\mathcal{F}_{g,n,b,c}^{x}$ are discussed: conventional upper-half plane (UHP) and crosscap constraints can be reformulated as extra constraints on a collection of bulk correlation functions.Comment: 41 pages + references (Minor corrections + references added comparing to v1

Fixture knowledge model development and implementation based on a functional design approach

The development of a knowledge model applied to fixture design is a complex task. The main purpose of such model is the development of a knowledge-based application to assist fixture designers. It comprises a detailed specification of the types and structures of data involved in the execution of the inference process needed to create a fixture solution for machining a raw part. A development method together with a knowledge model for automating fixture design is proposed. The development was divided into three parts: Design Process Model, definition of Top-level functional functions and Product Knowledge Model. Adopting a functional design approach, the fixture design solution was created in two levels: functional and detailed. The functional level is based on fixture functional elements and the detailed one is based on fixture commercial elements. The definitions and concepts used in the application are specified in several Units of Knowledge (UoK) that comprises the Fixture Knowledge Model. Common Knowledge Analysis and Design Structuring (CommonKADS), Methodology and software tools Oriented to KBE Applications (MOKA), Integrated DEFinition for Function Modelling (IDEF0) and Unified Modelling Language (UML) are the methodologies and techniques used in the proposed method. Finally, a prototype KBE application for fixture design was developed