Structures for covering large public spaces are more and more designed with innovative shapes involving combinations and/or modified forms of classical simple shapes such as plane, cylinder, sphere, ... etc. These innovative shapes are termed "freeform" and are created through the interaction between practical considerations for the structures and the artistic sense of the designers. Formex algebra and its programming language Formian can be of help in generating the geometry of freeform structures. In particular, there are two formex concepts that are of value in this context. These are the concepts of "pellevation" and "novation". The purpose of the present paper is to discuss the manner in which pellevation and novation can be used for freeform generation. In the paper, to begin with, the concepts of pellevation and novation are explained in terms of some simple examples. The process of freeform generation is then illustrated using a number of examples.

In the process of polishing with magnetic abrasive particles, several parameters affect the smoothness of the final surface of the part. These parameters include properties related to machining conditions, workpiece properties, or abrasive powder properties. The present paper deals with the effect of the kinetic parameters of the MAF process on the convex and concave surface of aluminum alloy experimentally. These parameters include rotational velocity, linear velocity, abrasive brush distance to the workpiece (gap), magnetic flux density, and angle of curvature. For this purpose, a spherical head magnet was used and the powder used was prepared by mechanical alloying method. Also, the two-way zero-degree raster movement strategy is used for the tool movement path. The experiment was designed using miniatub software. According to the results of analysis of variance, it was found that all the main factors or their interaction are effective. Also, the roughness changes on the convex surface are more than the concave surface. On the convex surface, the roughness changes with increasing curvature angle. On the convex surface of the workpiece, with increasing magnetic flux density, there is an increase in surface roughness changes, while on the concave surface, passing the magnetic flux density of 0. 53 Tesla, the progression of roughness changes occurs. The effect of velocity on the convex and concave surfaces of the workpiece is the same, and with increasing rotational speed from 125 to 2000 (rpm), the roughness changes of the concave surface of the workpiece increase by 57%.

Jig and fixture design for workpieces with freeform geometry has more complexity in comparison with the polyhedral parts. The locating and clamping system design construct the basis of the jig and fixture design activities. In this study, a theoretical analysis is suggested for automatic design of clamping points for freeform workpieces. The clamping design is performed in three main stages, in which the clamping application points are determined through the first two principles and are verified through the last stage. The mentioned principles consist of: (1) the minimum quantity of clamps, (2) the maximum clamping force components on the locating directions and (3) the workpiece static stability under the external wrenches. After mathematical modeling, the suggested analysis was implemented into the already designed CAFD framework by the authors. Three machining models were chosen as case studies to evaluate the capabilities of the implemented system in robust design of clamping layout. The minimum quantity of clamps (single clamp for two case studies and double clamp for the third one) was designed by the developed method that verified the robustness and reliability of the suggested and implemented clamping system design model. The automatic design of clamping scheme for workpieces (regardless of the geometry) besides its capability in integration with the other modules of fixture design activities provides the opportunity for the system to be used in industrial applications.

In this paper, we classify surfaces at a constant distance from the edge of regression on a translation surface of Type 1 in the three dimensional simply isotropic space I13 satisfying some algebraic equations in terms of the coordinate functions and the Laplacian operators with respect to the first, the second and the third fundamental forms of the surface. We also give explicit forms of these surfaces.

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Efforts to develop tissue-engineered skin for regenerative medicine have explored natural, synthetic, and hybrid hydrogels. The creation of a bilayer material, with the stratification exhibited by native skin, is a complex problem. The mechanically robust, waterproof epidermis presents the stratum corneum at the tissue/air interface, which confers many of these protective properties. In this work, we explore the effect of high temperatures on alginate hydrogels, which are widely employed for tissue engineering due to their excellent mechanical properties and cellular compatibility. In particular, we investigate the rapid dehydration of the hydrogel surface which occurs following local exposure to heated surfaces with temperatures in the range 100–200oC. We report the creation of a mechanically strengthened hydrogel surface, with improved puncture resistance and increased coefficient of friction, compared to an unheated surface. The use of a mechanical restraint during heating promoted differences in the rate of mass loss; the rate of temperature increase within the hydrogel, in the presence and absence of restraint, is simulated and discussed. It is hoped that the results will be of use in the development of processes suitable for preparing skin-like analogues; application areas could include wound healing and skin restoration.