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Geo-electrical soundings using the Schlumberger configuration were carried out in the coastal city srea of Khulna, Bangladesh, to identify different water bearing horizons within the coastal plain sands. Geo-electrical sounding data were interpreted by partial curve matching technique to obtain the initial model parameters. This initial model was then used to obtain the final layer parameters through inversion technique. The best-fitted models were correlated with the litholog. Results show that two major water bearing horizons exist in the area: (i) an upper zone consisting of fine grained sands having apparent resistivity of 2-10 Ω m and (ii) a lower zone consisting of medium to coarse grained sands with 6-38 Ω m apparent resistivity value. The resistivities for most of the aquifer zones are found to be very low, which may be due to the salinity of groundwater besides their packing and grain size.

Eco-friendly dyeing by using supercritical carbon dioxide as a medium has already been investigated worldwide due to the advantages of dyeing without water and recyclability of dyes and carbon dioxide. In this article, dyeing mechanism of poly(m-phenylene isophthalamide) was investigated in supercritical carbon dioxide. The obtained results showed that the dye uptake of Disperse Red 60 increased moderately with the temperature raising at constant pressure and achieved dyeing equilibrium after 70 min. By adding the carrier, diffusion coefficients of Disperse Red 60 in the polymer increased significantly in supercritical carbon dioxide. The activation energy for diffusion of Disperse Red 60 with and without carrier was 1165.91 and 1050.66 kJ mol−1, respectively. Moreover, the distribution coefficient, the standard affinity, the standard enthalpy, and the standard entropy of dyeing were also determined in supercritical carbon dioxide. These fundamental data are of vital importance on the green dyeing production of poly(m-phenylene isophthalamide).

Plate fin heat exchangers (PFHE) are characterized by very close temperature approaches and high thermal effectiveness, large heat transfer area per unit volume, low weight per unit transfer and possibility of heat exchange between many process streams. These advantages are only limited by operating fluid temperatures and pressures. The main target of this paper is to study the performance of plate fin compact heat exchangers and to provide full explanation of previous comparison methods of compact heat exchanger surfaces (plain, strip, louvered, wavy, pin, perforated and vortex) used in plate fin compact heat exchangers. We generalize these methods to identify the advantages and disadvantages of each type of geometry (more than sixty geometries studied) based on required size, entropy generation, pumping power, weight, and cost. The effect of using different surfaces on each side of the heat exchanger and design recommendations are also discussed.

Diesel engine emission has been considered as major air pollution sources. Feedstocks blending method is motivated by cost reduction and property enhancement. In this paper crude rubber seed oil and palm oil are mixed in 50:50 vol. % and converted to biodiesel. Thermophysical property of the biodiesel was studied. Blends with varying contents of diesel and biodiesel 5-20 vol. % were prepared. Engine emissions and combustion characteristics were measured and analysed. The CO emission was reduced but the exhaust gas temperature and NOx emission increased proportional to the blends ratio. Premixed combustion phase in all tested blends start earlier the neat diesel .Short ignition delay and lower heat release rate were noticed.