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| 2. |
- Qureshi, Abdul Sattar, et al.
(författare)
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Fruit waste to energy through open fermentation
- 2017
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Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - Amsterdam : Elsevier. ; 142, s. 904-909
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Konferensbidrag (refereegranskat)abstract
- This study aims to examine the nonsterilized fermentation conditions for coproduction of pectinases and lipase enzymes using several fruit wastes as an energy source. Thermophilic fungal strain, Penicillium expansum CM,1 39671 was used as a fermenting strain. The effect of process conditions including; nitrogen sources, pH, temperature, time and moisture contents, on the production of both enzymes were studied. The highest activities of pectinase and lipase (2817, 1870 U/g dry substrate) enzymes were found with orange peel feedstock, whereas the lowest activities of 1662 U/g and 1266 U/g were found with banana peel and papaya peel feedstocks respectively. Overall, pectinase showed higher enzymatic activities than lipase enzymes, both having similar increasing and decreasing trends, at all studied conditions. The optimum process conditions of peptone as a nitrogen source, pH 7, 40 degrees C, 5 days and 70% moisture contents, were found to show highest enzymatic activities for both enzymes. The orange peel feedstock showed no significant difference in both enzymes' activities at sterilized and nonnotarized process conditions. Pectinase and lipase enzymes showed (13791 U/g) and (8114 U/g) for sterilized and (14091 U/g) and (8324 U/g) for nonnotarized process conditions respectively. In addition, the fungal strains also produce bacteriocin-like compounds that could inhibit microbial growth. These findings will help to design and develop robust, cost-effective and less energy intensive enzyme production processes and consequently an efficient fruit waste to energy system through open fermentation. (C) 2017 The Authors. Published by Elsevier Ltd.
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| 3. |
- Raza, Wasim, et al.
(författare)
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A novel microchannel-twisted pinfin hybrid heat sink for hotspot mitigation
- 2024
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311 .- 1873-5606. ; 241
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Tidskriftsartikel (refereegranskat)abstract
- Thermal hotspots cause excessive localized temperature rise, leading to significant temperature gradients across the microprocessor, which is the primary reason for its inadequate performance and early failure. This study proposes microchannel-pinfin hybrid heat sinks incorporating twisted and non-twisted pinfins of various cross-sectional shapes (hexagonal, pentagonal, square, and triangular) to demonstrate energy-efficient hotspot mitigation in a microprocessor with highly non-uniform power distribution. Microchannels and pinfins are positioned at low- and high-heat-flux zones, respectively, to reduce the temperature variations utilizing their unequal heat transfer capabilities. Here, high- and low-heat-flux zones represent the microprocessor-core area (hotspot) and remaining chip area (background zone), characterized by heat fluxes of 300 W/cm2 and 50 W/cm2, respectively. The pinfin twisting angle varies from 0° to 360° at a step of 45°. Conjugate heat transfer analyses are conducted through numerical solutions of the continuity, Navier-Stokes, and energy equations. The performance of the proposed hybrid heat sinks is compared with the non-hybrid (NH) and hybrid circular pinfins (HCP) heat sinks at Re = 120–440. The hybrid heat sink featuring triangular pinfins twisted at 225° angle (HTP-225) exhibits a remarkable reduction of 48.2 % in the total thermal resistance (Rth) and 58.4 % in the temperature non-uniformity (δT,bs) as compared to the NH heat sinks at Re = 440. Compared to the HCP design, the HTP-225 design shows 26.9 % and 35.8 % lower Rth and δT,bs, respectively. Moreover, the HTP-225 heat sink outperforms the NH heat sink with 46.0 % and 57.0 % lower Rth and δT,bs, respectively, at an equal pumping power of 18.6 mW. Furthermore, the HTP-225 heat sink demonstrates a 96.4 % and 38.5 % higher critical hotspot heat flux dissipating capacity than the NH and HCP heat sinks, respectively, making it a viable and effective solution for alleviating hotspots in high-power-density devices.
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| 4. |
- Shahzad, Danish, et al.
(författare)
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Novel C-2 Symmetric Molecules as -Glucosidase and -Amylase Inhibitors : Design, Synthesis, Kinetic Evaluation, Molecular Docking and Pharmacokinetics
- 2019
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 24:8
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Tidskriftsartikel (refereegranskat)abstract
- A series of symmetrical salicylaldehyde-bishydrazine azo molecules, 5a-5h, have been synthesized, characterized by H-1-NMR and C-13-NMR, and evaluated for their in vitro -glucosidase and -amylase inhibitory activities. All the synthesized compounds efficiently inhibited both enzymes. Compound 5g was the most potent derivative in the series, and powerfully inhibited both -glucosidase and -amylase. The IC50 of 5g against -glucosidase was 0.35917 +/- 0.0189 mu M (standard acarbose IC50 = 6.109 +/- 0.329 mu M), and the IC50 value of 5g against -amylase was 0.4379 +/- 0.0423 mu M (standard acarbose IC50 = 33.178 +/- 2.392 mu M). The Lineweaver-Burk plot indicated that compound 5g is a competitive inhibitor of -glucosidase. The binding interactions of the most active analogues were confirmed through molecular docking studies. Docking studies showed that 5g interacts with the residues Trp690, Asp548, Arg425, and Glu426, which form hydrogen bonds to 5g with distances of 2.05, 2.20, 2.10 and 2.18 angstrom, respectively. All compounds showed high mutagenic and tumorigenic behaviors, and only 5e showed irritant properties. In addition, all the derivatives showed good antioxidant activities. The pharmacokinetic evaluation also revealed promising results
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| 5. |
- Sohail, Muhammad Tayyab, et al.
(författare)
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Impacts of urbanization, LULC, LST, and NDVI changes on the static water table with possible solutions and water policy discussions: A case from Islamabad, Pakistan
- 2023
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Ingår i: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Rapid urbanization, coupled with land use land cover changes (LULC), has caused stress on freshwater resources around the globe. As in the case of Islamabad, the capital of Pakistan, the population has increased significantly, creating a deficit of natural resources and affecting the environment adversely. Therefore, the purpose of this study is to examine the effects of urbanization and LULC on the decline of the static water table in Islamabad. It also seeks to analyze water policy issues in order to achieve sustainable water resource development. The excessive pumping of the existing groundwater has exceeded the safe limit, which is justified by the constantly growing population. However, the changes in the LULC of the study area have turned many green pastures into barren land. Our research data were obtained from the Capital Development Authority (CDA), Pakistan Meteorological Department (PMD), and Landsat Satellite images. After analyzing PMD and CDA data for the last 20 years (2000–2020), the results were interpreted using Arc GIS. It has been observed that the Normalized Difference Vegetation Index (NDVI) value increases as the Land Surface Temperature (LST) decreases. Therefore, the overall observation is a decreasing trend in Islamabad temperatures due to the increased vegetation in the study area during the period of 2000–2020. It was observed that there has been a considerable drop in water levels due to over-pumping in a few areas. It is primarily associated with the increasing population of the capital in the last 2 decades. This study uses a survey to explore the potential locations for check dams to enhance and recharge the groundwater aquifers in the capital, Islamabad. It suggests catchment areas throughout the Margalla Hills along with different localities, such as Rumli Village, Trail 5, and Shahdara.
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