Purpose: Microbial infections often produce pain and inflammation. Chemotherapeutic, analgesic and anti-inflammatory

This work investigates the effects of cutting parameters on surface roughness (Ra, µm), cutting temperature (T, °C) at the chip–tool interface and the material removal rate during hard machining of AISI 1015 (43 ± 1 HRC) steel using carbide insert under dry and spray impingement cooling environment. A combined technique using orthogonal array and analysis of variance was employed to investigate the contribution of spindle speed, feed rate, depth of cut and air pressure on responses. It is observed that with spray impingement cooling, cutting performance improves compared to dry cutting. The predicted multi-response optimization setting (N3-f1-d1-P2) ensures minimization of surface roughness, cutting temperature and maximization of material removal rate.

Summary Solar parabolic dish attracts most of the researchers with its higher concentration ratio and its modular ability. Parabolic dish concentration can be employed in many applications which falls under solar thermal and solar electricity production. This article presents a novel approach of designing and development of a low‐cost solar parabolic dish concentrator of 12.6 m2 aperture area with dual‐axis manual tracking, which can be utilized for process heating and electrical power generation simultaneously. The same set up has been fabricated in National Institute of Technology, Puducherry and ready for investigation and analysis on different prospective. The design concept of solar parabolic dish concentrator and dual‐axis tracking system and its economic analysis are elaborately discussed in this article. The complete procedure followed for the fabrication of the entire system is also highlighted. Based on the economic analysis it was found to be more economical than the other existing dish concentrators in the literature, which costs ₹6877.00 per square meter.

Keeping in view the pharmacological potential of azetidinones, thiazolidinones and coumarins, the title compounds containing these nuclei were synthesized. The 4-methyl -7-hydroxy coumarin (1) on treatment with hydrazine hydrate affords 2-hydrazo- 4-methyl -7-hydroxy coumarin (2). The N- (2’-imino-4’-methyl-7’-hydroxy coummarinyl)-imino substituted benzene (3) was synthesized by reaction of compound 2 with various aromatic aldehydes. Condensation of compound 3 with chloroacetyl chloride in presence of 1,4-dioxan and triethyl amine yields the 3-chloro-4- (substituted)-1-(2’-imino-4’-methyl-7’-hydroxy coumarinyl) azetidin-2-one (4a-d). Further more condensation of 3 with thioglycollic acid in presence of 1,4-dioxan and anhydrous aluminium chloride gives 2-(substituted phenyl)-3-(2’-imino-4’-methyl-7’-hydroxy coumarinyl)-1,3-thiazolidinone (4’a-d). Elemental and spectral characterization established the identity of these compounds. All the products were screened in vitro for their anti microbial activity against different strains of urinary tract pathogens. All compounds exhibited significant antimicrobial activity compared to the standard drug nitrofurantoin. Key words: Azetidinones, thiazolidinone, coumarin, nitrofurantoin, E. coli, P. auregenosa, K. pneumoniae, P. mirabilis E. faecalis, and S.aureus. Dhaka Univ. J. Pharm. Sci. Vol.4(2) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

The parabolic dish concentrator is one of the most efficient technologies to convert direct beam radiation into thermal energy for steam and power generation. The parabolic dish concentrates direct beam radiation from the sun on to a receiver at the focal point. The receiver plays a major role to transform the reflected solar radiation into thermal energy. The conversion efficiency of the dish is severely influenced by imperfection of the dish collector such as the contour of parabola, size of the facets aligned, positioning of the receiver and tracking of the system. These imperfections are mainly involved in the design, manufacturing, construction and operation of a parabolic dish collector. To overcome this imperfection, secondary reflector are normally deployed at the focal region of the receiver. The function of the secondary reflector reradiates the deviated rays from the primary concentrator onto the receiver. In this aspect, flat receiver is initially fabricated to evaluate the performance of the flat receiver without secondary reflector. In this paper, the experimental investigations on flat receiver for 12.6 m2 area of solar parabolic dish concentrator system to estimate the receiver temperature and overall heat transfer coefficient of the flat receiver. In order to estimate this, rectangular box type aluminium receiver is fabricated and placed at the focal point of 2.42 m from the base of the dish. The aperture area of dish concentrator system is 12.6 m2 area and it consists of 12 petals and in each petals 128 flat mirrors of size 7.5 cm × 7.5 cm with reflectivity of 0.95 are pasted on 1.2 mm thickness MS plate to form a parabolic dish concentrator. The azimuth and elevation manual tracking arrangements are made to track the dish continuously for different orientation of the sun. K-type thermocouples are used to measure the temperatures of the top and bottom of the receiver. To measure the maximum temperature of the receiver, experiments are carried out for stagnation conditions (without heat retrieval from the receiver). Experiments are carried out on 5th, 6th and 7th March 2018 from 10.00 am to 3.00 pm. For different direct beam solar radiation, the top and bottom temperatures, ambient temperatures are measured. The maximum temperature of 399°C is achieved at the bottom surface of the flat receiver for the beam radiation of 955 W/m2, and the corresponding top surface temperature of 58°C is achieved for the same flux. Based on the measured bottom surfaces temperatures, the overall heat transfer coefficient of bottom surface are estimated as 145.56 W/m2 K. Based on this study, further heat transfer analysis will be carried out for the developed flat receiver.