This paper presents the results of the analysis of 56,000 flat grids in a form suitable for minimum weight design.
This paper presents the results of the analysis of 56,000 flat grids in a form suitable for minimum weight design.
Recent developments in the design and manufacture of microcomputers together with improved simulation techniques make it possible to achieve the speed and accuracy required for the dynamic simulation of power systems in real time. This paper presents some experimental results and outlines new ideas on hardware architecture, mathematical algorithms and software development for this purpose. The results of power system studies are discussed, and a new system formulation is proposed in which the State equations and electrical network equations are partitioned; the network equations being solved separately on a host processor while the state equations of each generating unit are solved on slave units. A transputer based, parallel processing system connected to micro VAX computer is proposed for the simulation of the dynamics of a power system in realtime. Such a simulator can be used for the evaluation of instability over a long period of time resulting from persisting faults and for the study of voltage collapse phenomena in power systems.
Fracture surface of Zircaloy-2 specimens tested under constant crosshead speed in CH3OH/0.4 Vol. %HCI solution with and without selenium (25 ppm) addition was studied. Using a combined process of deformation and annealing, coarse grained material was also obtained and examined. Two modes of stress corrosion crack propagation were observed: an intergranular zone caused by stress assisted anodic dissolution, and a transgranular cleavage zone, due to hydrogen absorption.
A new approach has been introduced to construct deformation-mechanism maps for metals and solid solution alloys. For this purpose two computer programs named DEFOR and GRAPH have been written in BASIC to be run on IBM compatible personal computers. Using these programs, deformation - mechanism maps for a number of pure metals and a solid solution alloy (Ti-6wt% Al) have been plotted and effects of grain size and alloying element have been studied.
Industrial and experimental induction furnaces are used for melting various types of iron ingots, returned scraps and DRI sponge pellets to produce high purity cast - iron and steel heats. The lowest consumption of electrical energy determined for continuous feeding operation is 0.3 KWH/Kg for the production of cast - iron in a 1.5 - ton industrial furnace and 0.45 KWH/Kg for the production of steel in a 25- Kg experimental furnace. The optimum feeding rate for lowest energy consumption is 12.5 grams per second for continuous feeding of DRI in a 25 - Kg induction furnace. Similar measurements show that the optimum size of the DRI pellets is around 7 milimeters.
Elastic-plastic finite-element analysis applied to metalforming allows the real macroscopic properties of the workpiece to be incorporated. This paper presents the results of an experimental study of the initiation of cracking in side-pressing of a heat-treated aluminium alloy (Duralloy 2014). Using an F. E. analysis, these are related to various fracture criteria. It is found that the criterion of generalised plastic work correlates well with the change in fracture site from the centre of the billet to the outer corner as the geometric shape becomes more oblate. For central cracks the limiting deformation is about 13%, but when these are suppressed the deformation can continue to nearly 50%.
The freezing process. microstructures and phase relationships in some experimental cast tool steels have been investigated and developed under the various solidification conditions. Experimental steels were based on AISI M2 and M10 grades high speed steels. Addition of carbide forming elements such as niobium and titanium with and without extra carbon were made to the molten bath of the base steels. The chemical composition adjustment and the microstructural and property changes are discussed in relation of possibilities for the development of tools cast close to finished shape with acceptable mechanical properties and lower production cost.
The modified out-in fuel management strategy was applied to the core loading design for the first four cycles of the Bushehr (Iran-1) KWU designed Pressurized Water Reactor (PWR). The minimum peak-to-average power density was chosen as the objective function of the optimization process. Lattice homogenization and group constants generation were performed by using the LEOPARD computer code. For core calculations the ERUPT code was applied. The optimum core configurations were designed after several hand shufflings of fuel assemblies. For the equilibrium cycle, a satisfactory value of 2.73 was found for the peaking power factor. The average discharge burn-up of this cycle was determined to be around 33,700 MWD/MTU.
One of the major disadvantages of using Branch and Bound algorithm to solve permutation bases problems by computer is the size of main memory required. The single Array Branch and Bound (SABB) method introduction here aims to overcome this deficiency, using only N memory locations as a vector of size N, and a single cell C with N bits.
A mathematical model has been developed for the prediction of the collection efficiency of submicron particles in the conduit type scrubber. The model has been tested with the data in the literature [1,3].