This paper describes a system for modeling, animating, previewing and rendering articulated objects. The system has a modeler of objects that consists of joints and segments. The animator interactively positions the articulated object in its stick, control vertex, or rectangular prism representation and previews the motion in real time. Then the data representing the motion and the models is sent to a multicomputer [iPSC/2 Hypercube (Intel)]. The frames are rendered in parallel, exploiting the coherence between successive frames, thus cutting down the rendering time significantly. Our main aim is to make a detailed study on rendering of a sequence of 3D scenes. The results show that due to an inherent correlation between the 3D scenes, an efficient rendering can be achieved. 相似文献
This study aimed to reveal the soil properties in the research area by using various geophysical methods. Physical parameters determining soil characteristics give us a chance to approach how the soil behaves during an earthquake. Thus, precautions can be taken to minimize earthquake damage. Also, safe construction against earthquake effects is important. The studied area is a tectonically and geothermally active area. İzmir Fault zone is passing through the investigation area and trending E–W direction. To investigate soil parameters at this active tectonic region, microtremor method data were recorded and the multichannel analysis of surface waves (MASW) method at 27 profiles was implemented in the study area. Additionally, these methods were supported by the spatial auto correlation (SPAC) method in center spot. Shear wave velocities up to 30 m, soil classification according to the National Earthquake Hazards Reduction Program (NEHRP), site amplification, predominant site period, amplification factor, ground vulnerability index, and shear wave velocity changes up to 300 m were obtained by evaluating the data collected from the applied geophysical methods. VS30 values varied between 700 and 1100 m/s in the southernmost part of the study area, corresponding to a C and B type as soil classification. While the predominant period values were taken as the lowest value of 0.2 s, it was observed to increase up to 5.5 s on the alluvial unit in the northern parts of the study area. The ground vulnerability index, which is directly related to the probability of earthquake damage, was found to be quite high in some parts of the study area. In this paper, we propose microzonation maps for the Balçova district, based on the variation of the soil dynamic parameters.
Previously published experiments on freeze-drying of foamed milk by microwaves are explained with an alternative theoretical model. The frozen milk foam is assumed to consist of parallel thin plates. A low-pressure gas stream consisting of air and water vapor mixture is believed to circulate freely in voids between plates. Air stream provides additional energy for the freeze-drying, helps to remove the sublimating water vapor and prevents an excessive icrowave heating of the dry milk foam. 相似文献
The software is developed in FORTRAN to obtain the cooling curves of powder metallurgy (P/M) of porous materials. The software is written in two-dimensional form and in cylindrical coordinates. The thermal conductivity of the porous materials is obtained using empirical correlations given in the literature. The natural convection, nucleate boiling and film boiling processes without and with radiation are considered in the analysis. The heat transfer coefficients on vertical and horizontal surfaces are calculated using the empirical correlations given in the literature. Energy equations are solved using the control volume method, but the effect of pore geometries is not considered in the analysis. Examples of the cooling curves are given for plain carbon steel with the water as the quenchant for 2.5%, 5%, 10%, 15% and 20% porosities. It is shown that the software can be used for different quenchants and the porous materials with different geometries. 相似文献
It is known that electrospinning is the most practical technique to obtain unique nanofibrous structures, such as neat PLA (polylactide) and PLA filled with POSS (Polyhedral Oligomeric Silsesquioxane) particles. On the other hand, due to the so many different process parameters to consider, production of these fibers are extremely difficult and time consuming. That is, use of a certain statistical optimization technique in the design of experiments would be necessary. Therefore, the main purpose of this study was to determine the optimum electrospinning parameters by applying the Taguchi technique first to neat PLA and then to reveal the applicability of these parameters for the electrospinning of PLA/POSS nanofibers. It was observed that instead of conducting 81 experiments to determine the most significant four optimum process parameters for PLA, use of Taguchi L9 orthogonal array experiment matrix, that is, conducting only nine experiments, reduced time, labor and material consumption considerably. For the smallest electrospun PLA fiber diameter, the optimum parameters determined were; “PLA solution concentration” of 8% w/v, “solution feeding rate” of 1.8 mL/h, “needle-to-collector distance” of 18 cm, and “applied voltage” of 15 kV. Moreover, it was generally concluded that these same parameters could be also used for the electrospinning of PLA/POSS nanofibers after addition of only 3 wt% KCl salt into the polymer solution. 相似文献
Summary A new method is described for the production of macroporous beads by copolymerization of styrene and divinylbenzene initiated by azo linked polytetrahydrofuran, which was obtained by silver salt-diacid chloride technique. Swelling properties of the beads in various solvents were studied. 相似文献
In this study, improvements in mechanical and thermal behavior of short glass fiber (GF) reinforced diglycidyl ether of bisphenol-A (DGEBA) based epoxy with hydroxyl terminated polybutadiene (HTPB) modification have been studied. A silane coupling agent (SCA) with a rubber reactive group was also used to improve the interfacial adhesion between glass fibers and an epoxy matrix. 10, 20, and 30 wt% GF reinforced composite specimens were prepared with and without silane coupling agent treatment of fibers and also HTPB modification of epoxy mixture. In the ruber modified specimens, hardener and HTPB were premixed and left at room temperature for 1 hr before epoxy addition. In order to observe the effects of short glass fiber reinforcement of epoxy matrix, silane treatment of fiber surfaces, and also rubber modification of epoxy on the mechanical behavior of specimens, tension and impact tests were performed. The fracture surfaces and thermal behavior of all specimens were examined by scanning electron microscope (SEM), and dynamic mechanical analysis (DMA), respectively. It can be concluded that increasing the short GF content increased the tensile and impact strengths of the specimens. Moreover, the surface treatment of GFs with SCA and HTPB modification of epoxy improved the mechanical properties because of the strong interaction between fibers, epoxy, and rubber. SEM studies showed that use of SCA improved interfacial bonding between the glass fibers and the epoxy matrix. Moreover, it was found that HTPB domains having relatively round shapes formed in the matrix. These rubber domains led to improved strength and toughness, due mainly to the “rubber toughening” effect in the brittle epoxy matrix. 相似文献