EXPERIMENTAL STUDY ON A THREE-BED ADSORPTION CHILLER

M. Z. I. KHAN,S. SULTANA,B. B. SAHA,A. AKISAWA 대한설비공학회 2011 International Journal Of Air-Conditioning and Refr Vol.19 No.4

This article presents the experimental results of a three-bed advanced adsorption chiller using silica gel–water as the adsorbent–refrigerant pair. The three-bed adsorption chiller comprises three sorption elements (Hexs), one evaporator and one condenser. In the present study, the heat source temperature varies from 55°C to 80°C along with coolant inlet temperature at 30°C and the chilled water inlet temperature at 14°C. Mass recovery process occurs between Hex1 and Hex2 and no mass recovery with Hex3. The performances in terms of cooling capacity (CC) and coefficient of performance (COP) are compared with those of conventional three-bed without mass recovery scheme. Results show that three-bed with mass recovery scheme provides more CC values than those provided by the three-bed system without mass recovery scheme while it provides better COP values for 65–75°C heat source temperature.

Synthesis and analysis of the influence of Eu3+ on the structural, ferromagnetic, dielectric and conductive characteristics of Ni0.4Zn0.45Cu0.15Fe(2-x)EuxO4 composites using conventional double sintering ceramic method

I. N. Esha,Md. Al-Amin,F. T. Z. Toma,Enayet Hossain,M. N. I. Khan,Kazi Hanium Maria 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.5

Conventional double sintering ceramic method has been followed to prepare a series of Eu substituted Ni0.4Zn0.45Cu0.15Fe(2-x) EuxO4 (NZCFEO) ferrites with x = 0.00, 0.02, 0.04, 0.07, 0.10, 0.12, 0.15. X-ray diffraction peaks confirm the single phase cubic spinel structures of all the samples. The lattice parameter is found to be distorted with the addition of Eu into the samples. X-ray density and bulk density increase with the increase of Eu content. Better crystallization has been obtained with the decreasing porosity as a result of increasing Eu3+ concentration. The dielectric constant of the samples shows a decreasing trend while both AC and DC resistivities are observed to increase with the increase of Eu3+ concentration. The high resistivity offers greater value of the activation energy. Permeability is found to decrease with increasing Eu content. Saturation magnetization changed significantly with Eu3+ concentration. Noteworthy decrease of the Curie temperature is observed with the addition of Eu substituent.

2-Methoxystypandrone improves in vitro-produced bovine embryo quality through inhibition of IKBKB

Mesalam, A.,Khan, I.,Lee, K.L.,Song, S.H.,Chowdhury, M.M.R.,Uddin, Z.,Park, K.H.,Kong, I.K. Butterworths, etc 2017 Theriogenology Vol. No.

2-Methoxystypandrone (2-MS), a naphthoquinone from Polygonum cuspidatum, has been reported to exhibit antioxidant activities. However, its pharmacological properties have not been fully studied in vitro culture system of oocytes and embryos development. In this study, we examined the effects of 2-MS on bovine blastocyst developmental competency during preimplantation using TUNEL assay, qRT-PCR and immunocytochemistry. Oocytes were treated with 1 μM 2-MS during maturation, followed by in vitro fertilized and the zygotes were cultured. We observed that blastocyst development was significantly higher in the 2-MS treated oocytes (45.29%) compared to control groups (32.21%). We also found that 2-MS treatment significantly increased total cell number and decreased the apoptotic cells in Day-8 blastocyst. Finally, we examined the signal pathway affecting the embryo development after the 2-MS treatment. We detected a significant decrease in the mRNA levels of NFKB1, IKBKB, COX2, NOS2, BAX, CASP3, and JAK2 after 2-MS treatment, however, the mRNA level of the anti-apoptotic gene BCL2 was significantly higher than that in the control. Moreover, protein expression levels of NFKB1, IKBKB, and COX2, and 8-oxoG DNA lesion decreased significantly in the 2-MS treatment group, compared to the control. In summary, our findings suggested that treatment of oocytes with a potential anti-oxidant, 2-MS during IVM improved in vitro developmental competence of bovine embryos.

Equilibrium, kinetics and thermodynamic studies for the removal of organophosphorus pesticide using Amberlyst-15 resin: Quantitative analysis by liquid chromatography–mass spectrometry

Mu. Naushad,Z.A. ALOthman,M.R. Khan,N.J. ALQahtani,I.H. ALSohaimi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.6

In the present paper, Amberlyst-15 resin was used for the removal of malathion. Various experimentalparameters such as effect of pH, contact time, resin dose, initial malathion concentration andtemperature were studied to find the optimum conditions for malathion removal. The removal rate ofmalathion by Amberlyst-15 was rapid and equilibrium was established within 30 min. Kinetic studiesshowed better applicability for pseudo-second-order model and equilibrium data was best fitted toFreundlich isotherm model. The thermodynamic parameters showed that the adsorption of malathionwas feasible, endothermic and spontaneous. The concentration of malathion was determined usingultra-performance liquid chromatography–tandem mass spectrometry.

Study of the Structural, Electrical and Magnetic Properties of Calcium (Ca) and Strontium (Sr) Substituted Barium Titanate (BaTiO3) Ceramics

F. T. Z. Toma,I. N. Esha,Md. Al-Amin,M. N. I. Khan,Kazi Hanium Maria 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.10

The structural, electrical and magnetic properties have been investigated for Ca and Sr substituted Ba1-x(Ca0.5Sr0.5)xFe0.5Ti0.5O3(where x = 0.0, 0.1 0.2, 0.3, 0.4) which have been synthesized by a solid state reaction technique and sintered at 1200 oC for 3 hours. In this study BaTiO3 is modified with Fe in lattice B-site. The X-ray diffraction pattern of the prepared samples have indicated single phase cubic perovskite structure. Lattice constant of the samples have decreased with the increasing Ca and Sr contents which follows Vegard’s law. The microstructure of the samples showed that the grain growth rate was greately changed by doping contents. Doping contents have influenced the dielectric constant within the frequency range of 1 kHz to 120 MHz. It is observed that AC resistivities of the prepared samples have been decreased with increasing frequency while DC resistivities have been decreased with increasing temperature confirming the semiconductor behavior of the prepared ceramics. The magnetic hysteresis loops had also been observed by VSM at room temperarure. The initial permeability followed decreasing trend with increasing doping contents. The structural, electrical and magnetic properties have been investigated for Ca and Sr substituted Ba1- (Ca0.5Sr0.5)xFe0.5Ti0.5O3(where x = 0.0, 0.1 0.2, 0.3, 0.4) which have been synthesized by a solid state reaction technique and sintered at 1200 oC for 3 hours. In this study BaTiO3 is modified with Fe in lattice B-site. The X-ray diffraction pattern of the prepared samples have indicated single phase cubic perovskite structure. Lattice constant of the samples have decreased with the increasing Ca and Sr contents which follows Vegard’s law. The microstructure of the samples showed that the grain growth rate was greately changed by doping contents. Doping contents have influenced the dielectric constant within the frequency range of 1 kHz to 120 MHz. It is observed that AC resistivities of the prepared samples have been decreased with increasing frequency while DC resistivities have been decreased with increasing temperature confirming the semiconductor behavior of the prepared ceramics. The magnetic hysteresis loops had also been observed by VSM at room temperarure. The initial permeability followed decreasing trend with increasing doping contents.

Effects of Substituting Cottonseed Meal with Sunflower Meal in Rations for Growing Buffalo Calves

Yunus, A.W.,Khan, A.G.,Alam, Z.,Sultan, J.I.,Riaz, M. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.5

A growth trial of 60 days with 16 male buffalo calves (10 to 11 months age; 100${\pm}$7 kg live weight mean) was conducted to investigate comparative efficacy of cottonseed meal (CSM) and sunflower meal (SFM). Cottonseed meal was substituted isonitrogenously with SFM at 0, 12, 24 and 36% levels in four rations viz. A, B, C and D. Daily feed consumption was 5.07, 4.30, 4.17 and 3.20 kg, while daily weight gain was recorded to be 0.98, 0.74, 0.57 and 0.33 kg under rations A, B, C and D, respectively. In the digestibility and nitrogen balance trial using eight calves, digestibility of organic matter was 63.2, 62.9, 62.1 and 61.7, respectively. Nitrogen retained as percent of intake did not differ significantly. Sunflower meal was purchased at half the price of CSM but economics of weight gain did not favor SFM inclusion in rations. Results suggested that SFM should not be fed to buffalo calves gaining more than 0.7 kg/day.