Copper slag as sand replacement for high performance concrete

This paper reports on an experimental program to investigate the effect of using copper slag as a replacement of sand on the properties of high performance concrete (HPC). Eight concrete mixtures were prepared with different proportions of copper slag ranging from 0% (for the control mix) to 100%. Concrete mixes were evaluated for workability, density, compressive strength, tensile strength, flexural strength and durability. The results indicate that there is a slight increase in the HPC density of nearly 5% with the increase of copper slag content, whereas the workability increased rapidly with increases in copper slag percentage. Addition of up to 50% of copper slag as sand replacement yielded comparable strength with that of the control mix. However, further additions of copper slag caused reduction in the strength due to an increase of the free water content in the mix. Mixes with 80% and 100% copper slag replacement gave the lowest compressive strength value of approximately 80 MPa, which is almost 16% lower than the strength of the control mix. The results also demonstrated that the surface water absorption decreased as copper slag quantity increases up to 40% replacement; beyond that level of replacement, the absorption rate increases rapidly. Therefore, it is recommended that 40 wt% of copper slag can used as replacement of sand in order to obtain HPC with good strength and durability properties.     

Diels-Alder Reactions with Some N-Substituted Maleimides

A series of endo-carbonyl-1,2-dihydro-(3,4,5,6-tetraphenyl)-N-substituted phthalimides ( 5a – e ) has been synthesized by the Diels-Alder reaction of tetracyclone ( 2 ) with some N-substituted maleimides ( 1a – e ). Decarbonylation of the adducts 5a , b afforded the dihydrophthalimides 6a , b . The dihydro adducts 7a , b and 8a , b were obtained when phencyclone ( 3 ) and 2,3-dimethylfurane ( 4 ) were allowed to react with maleimides 1a , b . Dehydrogenation of the dihydro adducts 5a , b , 6a , b , 7a , b , 8a , b yielded the adducts 9a , b , 10a , b , 11a , b , 12a , b , respectively. The dihydro adducts 6a , b , in contrast to the dihydro adducts 7a , b , reacted further with one molecule of a dienophile to provide the dihydro adducts 14a , b , 15a , b and 16a , b . The dihydro adducts 16a , b , were also obtained in one step when one molecule of 2 was allowed to react with two molecules of each of the N-substituted maleimides 1a , b .     

Springback prediction and reduction in deep drawing under influence of unloading modulus degradation

Springback is considered as one of the major problems in deep drawing of high-strength steels (HSS) and advanced high-strength steels (AHSS) which occurs during the unloading of part from the tools. With an ever increasing demand on the automotive manufactures for the production of lightweight automobile structures and increased crash performance, the use of HSS and AHSS is becoming extensive. For the accurate prediction of springback, unloading behavior of dual phase steels DP600, DP1000 and cold rolled steel DC04 for the deep drawing process is investigated and a strategy for the reduction of springback based on variable blankholder force is also presented. Cyclic tension compression tests and LS-Opt software are used for the identification of material parameters for Yoshida-Uemori (YU) model. Degradation of the Young’s modulus is found to be 28 and 26 and 14 % from the initial Young’s modulus for DP600, DP1000 and for the DC04 respectively for the saturated value. A finite element model is generated in LS-DYNA based on the kinematic hardening material model, namely Yoshida-Uemori (YU) model. The validation of numerical simulations is also carried out by the real deep drawing experiments. The springback could be predicted with the maximum deviation of 1.1 mm for these materials. For DP1000, the maximum springback is reduced by 24.5 %, for DP600 33.3 and 48.7 % for DC04 by the application of monotonic blankholder force instead of a constant blankholder force of 80 kN. It is concluded that despite the reduction of Young’s modulus, the springback can be reduced for these materials by increasing the blankholder force only in last 13 % of the punch travel.     

Stability of peroxidized oils and fat to high temperature heating

The fatty acid compositions of extracted and commercial samples of cottonseed oil, groundnut oil, sesame oil and butter fat were determined by gas-liquid chromatography. These fats were subjected to frying temperature (195 ºC) for 3 hours and the peroxide value, iodine value, free fatty acid content and the carbonyl value were determined at hourly intervals. The stability of the oils did not correlate well with the ratio of C18:2 to C81:1 nor with the degree of unsaturation. Also, it was not a function of the susceptibility of these oils and fat to hydrolyse during the heating process. The data suggest that the fatty acids, present in these oils and fat, influence each other's oxidation and thus affecting the rate of oxidation. It appears that one of the major predisposing factors in the degradation of these oils and fat is the amount of saturated fatty acids which are present in contact with unsaturated and peroxidised fatty acids. This explanation has been discussed in relation to the degree of unsaturation of the oils used in the experiments and their vitamin E contents.     

Electroencephalographic changes in rats received antigens of different parasites

The prevalence of epilepsy in developing countries is much higher than in developed ones. Some of the highest prevalence rates in developing countries have been reported from tropical Africa where parasitic infections are endemic. This work was carried out to assess the effect of different parasitic antigens on the activity of cerebral cortex in rats. Nine crude antigens were used: Adult Fasciola, adult S. mansoni, hydatid cyst, T. spiralis, E. histolytica, Acanthamoeba spp. G. lamblia, Cryptosporidium spp. and crude antigen of T. gondii. All the parasitic antigens induced electroencephalographic changes compared with baseline tracings.     

Blood vessel segmentation and extraction using H-minima method based on image processing techniques

Multimedia Tools and Applications - In this paper, the H-minima transform is used for blood vessel segmentation. The aim of this study is to get the high accuracy of blood vessel segmentation in...     

Implementation of an LVQ neural network with a variable size: algorithmic specification, architectural exploration and optimized implementation on FPGA devices

This paper presents an optimizing methodology for the implementation of a Learning Vector Quantization (LVQ) neural network in a Field Programmable Gate Array (FPGA) device. Starting from an algorithmic specification in the form of a Factorized and Conditioned Data Dependence Graph (GFCDD), we suggest a design methodology of the LVQ-dedicated architecture. This formal methodology is called AAA, “Algorithm Architecture Adequation”. Using graph transformations, it allows the generation of an optimized circuit implementation at the Register Transfer Level (RTL). It is associated to the SynDEx-IC software tool. Based on this formal methodology, we are able to explore and generate various LVQ network implementations by varying the LVQ sizes while minimizing the hardware resources and the design time. In addition, real-time constraints should be respected to ensure a reliable classification of vigilance states in humans from electroencephalographic signals (EEG). To validate our approach, the optimized LVQ implementation was tried on two types of Virtex devices.