Modelling of electro hydraulic free and die forming of sheet steels

Electro hydraulic forming of a range of different sheet steels was studied experimentally and with finite element methods. Four carbon and stainless sheet materials were studied. In this paper we present results on a mild steel (IF210), two high strength steels (DPX800 and TRIP700) and one stainless steel (1.4509). The flow properties of the materials were evaluated at a range of strain rates up to 1000/s. These were typical strain rates in the FE simulations. The flow properties were characterized with the Johnson Cook model. Electro hydraulic forming trails were performed with a chamber of water with a pair of electrodes on one side of the sheet. In one case free forming was performed and in the other case forming was performed into a truncated conical die. Geometrical shapes and strain distributions were evaluated after forming. A finite element model was formulated in ABAQUS explicit. The model takes the chamber filled with water into account and the effect of the electrical discharge is modeled as a pressure wave originating from the location of the electrodes. The sheet is given the properties defined by the Johnson Cook model and stiff tools are used. The forming of the sheet is described including rebound effects at the tools. The model shows satisfactory results in relation to the experimental trials regarding both shape and strains of the pressed sheets.     

An Accurate Indoor RSSI Localization Algorithm Based on Active RFID System with Reference Tags

Radio frequency identification technologies are popular since their cost is very low and its data transmission based upon radio-wave communications. Where, the objects that are attached to tags are located using the reference tags. However, RSSI information suffers from the multipath propagation and anisotropic interference. So, the localization accuracy will be affected severely. Also, the multipath-propagation increases whenever the reference-tags increase, and so does for the cost, and signal interference. This paper presents a boundary virtual reference label algorithm for improving the indoor-efficiency by inserting some virtual reference tags on the boundary with establishing a linear regression model that eliminates unwanted tag information from the estimation procedure. The Results show that the localisation precision of the proposed approach has significantly increased, at least 78% without adding extra reference tags or radio frequency interference which represents a significant improvement over other algorithms .

     

Estimating the health damage costs of syrian electricity generation system using impact pathway approach

Based on the simplified impact pathway approach the environmental impacts from airborne pollutant emissions of Syrian electricity generation system have been assessed and the associated external damage costs to human health have been evaluated. The obtained results indicate that the environmental impacts can add considerable external cost to the typical generation cost. The estimated externalities vary between 2.5 and 0.07 US-cents per generated kWh for heavy fuel oil and NG fired power plants respectively. For the fuel oil fired power plants the resulting external cost, arise mainly from Sulphates impact, amounts to about 25% of the present generation costs. These results indicate the advantage of NG fired power plants as clean generation technology and the necessity of supplying oil fired power plants with SO₂ emission reduction technologies.     

Comparison of kjeldahl and dumas methods for determining protein contents of soybean products

The Kjeldahl and Dumas methods for quantifying nitrogen content were compared using nine soybean products having protein contents ranging from 0.5 to 90%. In addition to comparing day-to-day variability of the Dumas method, differences between and variabilities of two Kjeldahl systems and Kjeldahl operators were also evaluated. The Kjeldahl method gave slightly, but significantly, lower values than did the Dumas method. Both the Kjeldahl and Dumas methods had equivalent variabilities (same SD about the means). The ratios between the means for the Kjeldahl and Dumas (K/D) protein values ranged from 0.66 to 1.03. The conversion equation y=−0.00536+0.97188x (R ²=0.9997) was developed and validated to convert from Dumas to kjeldahl protein concentrations.     

Accurate estimation of formation permeability by means of petrophysical logs

Permeability can be considered as the one of the main petro-physical parameters that plays an important role in commercial production of reservoir. On the other hand, measuring the permeability is actually a principal challenge for investigators. Inasmuch as, taking core samples from every well and also surveying well-tested data require a large amount of time and capital, using an economical process is more interesting and it is the main cause to utilize electronic logging as a repeatable method. Artificial intelligence-based methods and especially least squares support vector machines (LSSVM) are reliable and accurate models. In the present work, the LSSVM has been trained by the Cuckoo optimization algorithm to predict permeability by means well-logging data including five different types of logs as input data. The correlation coefficient between the model prediction and the relevant real data is found to be about 0.99602 that can be nominated as an accurate yield.     

Convective heat transfer analysis of refined kerosene with alumina particles for rocketry application

A detailed experimental study of the fuel flow characteristic and the convective heat transfer of a nano fluid consisting of refined kerosene have been studied in the present work. Low volume fraction of 0.01 and 0.05 of Al₂O₃-refined kerosene has been studied. A horizontal tube of 4 mm in diameter was used for the fluid flow and the heat flow under various Reynolds number ranging from 500 to 5500 were investigated. SEM analysis showed particle size of alumina nanoparticle ranged from 32 nm–50 nm. It was found that, higher the volume fraction of the refined kerosene- Al₂O₃ nano fluid, larger is the heat transfer coefficient. Moreover it was found that with increase in volume fraction of nano particles in the fluid, the nano fluid’s viscosity also increased which results in an increase in friction factor. The friction factor and pumping power were also investigated under various Reynolds number and volume fraction. An increase of 16.33 % in convective heat transfer was observed at Reynolds number of 5500 for a volume fraction of 0.05 %. All results provide strong proof that the addition of nanoparticles intensified the above properties to a considerable rate.

     

The study of catalytic performance of silica-supported three metallic Fe–Co–Ce catalyst prepared using impregnation procedure for Fischer–Tropsch synthesis

We apply the wet impregnation procedure to prepare the Fe–Co–Ce catalyst supported by silica. The effects of operational conditions such as temperature, pressure, and the feed ratios of reaction on the selectivity and yield were studied. The production of light olefins from syngas (CO and H₂) over this catalyst in a fixed bed reactor via Fischer–Tropsch synthesis (FTS) was investigated. The reactor tests were determined through the design experiments.The optimum condition was determined in a way that the selectivity of methane was the least and other olefins have the maximum selectivity. The results indicated that the catalyst at 350°C, 3 bar, and syngas with H₂/CO ratio 1/1 has shown the better catalytic performance for FTS.