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Search Results: 1 - 10 of 1768 matches for " Qaisar Mahmood "
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Process Performance of Simultaneous Anaerobic Sulfide and Nitrate Removal

Qaisar Mahmood,CAI Jing,ZHENG Ping,Qaisar Mahmood,HUANG Ke-Tan,FU Lei,

生物工程学报 , 2006,
Abstract: The process performance of simultaneous anaerobic sulfide and nitrate removal was studied. The results showed that the process held a high sulfide and nitrate removal loading rate of 3.73kg/(m3 x d) and 0.80kg/(m3 x d), respectively, under steady state. It was capable of tolerating high influent substrate concentration (580mg/L and 110mg/L) with the optimum substrate concentration of 280mg/L and 67.5mg/L. It was capable of tolerating short hydraulic retention time (HRT) with the optimum HRT of 0.13d. Careful operation was needed when HRT was shortened because the process performance was deteriorated abruptly.
Activated sludge-mediated biodegradation of dimethyl phthalate under fermentative conditions

WU Donglei,MAHMOOD Qaisar,Wu Lili,ZHENG Ping,

环境科学学报(英文版) , 2008,
Abstract: The biodegradation of dimethyl phthalate (DMP) was investigated under fermentative conditions in this study. The nature of the intermediate compounds and the extent of mineralization were probed using high-pressure liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) G1]methods. The fermentative bacteria were able to biodegrade the DMP under anaerobic conditions, with the biodegradation rate of 0.36 mg DMP/(L?h). The results demonstrated that the DMP degradation under fermentative conditions followed the modified Gompertz model with the correlation coefficient of 0.99. Monomethyl phthalate (MMP) and phthalic acid (PA) were detected as the intermediates of DMP biodegradation. During the experiment, MMP was rapidly produced and removed; however, PA accumulated as the biodegradation was slower throughout the course of the experiment. The CODCr concentration decreased from 245.06 to 72.01 mg/L after the experimental operation of 20 d. The volume of methane produced was 3.65 ml over a period of 20 d and the amount of methane recovered corresponded to 40.2% of the stoichiometric value. The CODCr variation and methane production showed that the DMP could not be completely mineralized under the fermentative conditions, which implied that the fermentative bacteria were not able to biodegrade DMP entirely.
Scattering of an Arbitrarily Oriented Electric Dipole Field from an Infinitely Long Db Circular Cylinder
Abid Mahmood;Ahsan Illahi;Aqeel Abbas Syed;Qaisar Abbas Naqvi
PIER M , 2012, DOI: 10.2528/PIERM11120105
Abstract: Analytic expressions for the scattered magnetic vector potential from an infinitely long DB circular cylinder are presented. An arbitrarily oriented electric dipole is considered as a source of excitation that induces surface currents on the DB circular cylinder. Approximate far field expressions for magnetic vector potential are also derived in this setting. Numerical results of the scattering from the DB cylinder are also presented and compared with those of the PEC cylinder.
Isolation,identification and characterization of nitrate-reducing and sulfide-oxidizing bacteria

CAI Jing,ZHENG Ping,HU Bao-lan,Qaisar Mahmood,
,郑平,胡宝兰,Qaisar Mahmood

微生物学报 , 2007,
Abstract: Bacterial strains CB and CS were isolated from the Anoxic Sulfide Oxidizing (ASO) reactor working under steady-state with sulfide and nitrate as electron donor and acceptor,respectively. Based on electron microscopy,physiological test and 16S rDNA phylogenetic sequence analysis,the isolate CB was very close to Bacillus pseudofirmus and the isolate CS was very close to Bacillus hemicellulosilytus and Bacillus halodurans. The 16S rDNA sequences of both isolates were submitted to GenBank,NCBI and accession numbers EF542806 and EF542807 were allotted for isolates CB and CS,respectively. According to Biolog carbon source utilization test,the isolate CB is weak to use the carbon sources,while the isolate CB can use many carbon sources. Both the isolate CB and the isolate CS are able to use nitrate for sulfide oxidation. The isolate CS has greater capability to oxidize sulfide with nitrate as electron acceptor.
Global Stability of SEIQRS Computer Virus Propagation Model with Non-Linear Incidence Function  [PDF]
Qaisar Badshah
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.611170
Abstract: In this paper, we present an SEIQRS epidemic model with non-linear incidence function. The proposed model exhibits two equilibrium points, the virus free equilibrium and viral equilibrium. The model stability is connected with the basic reproduction number R0. If R0 < 1 then the virus free equilibrium point is stable locally and globally. In the opposite case R0 > 1, then the model is locally and globally stable at viral equilibrium point. Numerical methods are used for supporting the analytical work.
Anoxic biodegradation of dimethyl phthalate (DMP) by activated sludge cultures under nitrate-reducing conditions
Anoxic biodegradation of dimethyl phthalate (DMP) by activated sludge cultures under nitrate-reducing conditions

WU Dong-lei,HU Bao-lan,ZHENG Ping,Qaisar Mahmood,
WU Dong-lei
,HU Bao-lan,ZHENG Ping,Qaisar Mahmood

环境科学学报(英文版) , 2007,
Abstract: Worldwide extensive use of plasticized plastics has resulted in phthalates pollution in different environment. Nitrates from industry and agriculture are also widely disseminated in the soils, natural waters and wastewaters. Dimethyl phthalate (DMP) biodegradation by activated sludge cultures under nitrate-reducing conditions was investigated. Under one optimized condition, DMP was biodegraded from 102.20 mg/L to undetectable level in 56 h under anoxic conditions and its reaction fitted well with the first-order kinetics. Using the high-performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC-MS) analysis, mono-methyl phthalate (MMP) and phthalic acid (PA) were detected as the major intermediates of DMP biodegradation. When combined with the determination of chemical oxygen demand (COD(Cr)) removal capacity and pH, DMP was found to be mineralized completely under anoxic conditions. The biodegradation pathway was proposed as DMP -->MMP-->PA-->...-->CO2 + H2O. The molar ratio ofDMP to nitrate consumed was found to be 9.0:1, which agrees well with the theoretical stoichiometric values of DMP biodegradation by nitrate-reducing bacteria. The results of the non-linear simulation showed that the optimum pH and temperature for the degradation were 7.56 and 31.4 degrees C, respectively.
Control strategy of shortcut nitrification
LU Gang,ZHENG Ping,JIN Ren-cun,QAISAR Mahmood,
LU Gang
,ZHENG Ping,JIN Ren-cun,QAISAR Mahmood

环境科学学报(英文版) , 2006,
Abstract: Shortcut nitrification for ammonium-rich wastewater is energy-saving and cost-effective procedure that has become one of the hotspots in the field of biological denitrogenation. An orthogonal experiment was performed to study the combined effects of opera
蔡靖 郑平* Qaisar Mahmood 黄可谈 傅磊
生物工程学报 , 2006,
Abstract: 研究了同步厌氧生物脱氮除硫工艺的性能。该工艺具有很高的硫化物和硝酸盐转化潜能,稳态运行时的容积硫化物去除率和容积硝酸盐去除率分别为3.73kg/(m3·d)和0.80kg/(m3·d);能够耐受580mg/l的硫化物浓度和110mg/l的硝酸盐浓度,适宜浓度分别为280mg/l和67.5mg/l;能够耐受较高的水力负荷,适宜的水力停留时间为0.13d,反应器运行性能会因缩短水力停留时间而突发性恶化。
Antihyperlipidemic and Hepatoprotective Activity of Dodonaea viscosa Leaves Extracts in Alloxan-Induced Diabetic Rabbits (Oryctolagus cuniculus)
Maqsood Ahmad, Qaisar Mahmood, Kamran Gulzar1, Muhammad Shoaib Akhtar1, Mohammad Saleem and Muhammad Imran Qadir*
Pakistan Veterinary Journal , 2012,
Abstract: Hyperlipidemia is associated with diabetes and hepatotoxicity has emerged as a common clinical complication by antidiabetics. The present study was conducted to determine the antihyperlipidemic and hepatoprotective activity of Dodonaea viscosa leaves extracts in the alloxan-induced diabetic rabbits. The rabbits (n = 70) were divided into seven groups including normal and diabetic control, the remaining were aqueous, aqueous:methanol (70:30), aqueous:methanol (50:50), aqueous: methanol (30:70), and methanol extracts given for 30 days. Serum levels of triglycerides, total cholesterol, LDL-cholesterol, HDL-cholesterol, ALT and AST were estimated by using commercially available kits. The oral administration of aqueous:methanol (70:30) extract of the Dodonaea viscosa leaves significantly (P<0.01) decreased the raised parameters (triglyceride, total cholesterol and LDL-cholesterol) to normal values. But the extract has significantly increased HDL-cholesterol, ALT and AST levels. For the aqueous:methanol (70:30) extract given animals, the average serum level of total cholesterol was 60.00±1.30 mg/dL, LDL-cholesterol was 92.80±2.29 mg/dL, HDL-cholesterol was 31.80±1.0 mg/dL and triglyceride was 15.40±0.75 mg/dL while the average serum levels of ALT and AST were 45.60±3.08 and 27.20±1.36 IU/dL, respectively. It is concluded from the study that aqueous:methanolic (70:30) extract of Dodonaea viscosa leaves exerts antihy- perlipidemic and hepatoprotective effects in the alloxan-induced diabetic rabbits.
Production and application of anaerobic granular sludge produced by landfill
WANG Jin,ZHANG Zhen-ji,ZHANG Zhi-feng,QAISAR Mahmood,ZHENG Ping,
,ZHANG Zhen-ji,ZHANG Zhi-feng,QAISAR Mahmoo,ZHENG Ping

环境科学学报(英文版) , 2007,
Abstract: Sludge granulation is considered to be the most critical parameter governing successful operation of an upflow anaerobic sludge blanket and expanded granular sludge bed(EGSB)reactors.Pre-granulated seeding sludge could greatly reduce the required start- up time.Two lab-scale and a pilot-scale EGSB reactors were operated to treat Shaoxing Wastewater Treatment Plant(SWWTP) containing wastewater from real engineering printing and dyeing with high pH and sulfate concentration.The microbiological structure and the particle size distribution in aerobic excess sludge,sanitary landfill sludge digested for one year,and the granular sludge of EGSB reactor after 400 d of operation were analyzed through scanning electron microscopy (SEM) and sieves.The lab-scale EGSB reactor seeded with anaerobic sludge after digestion for one year in landfill showed obviously better total chemical oxygen demand (TCOD)removal efficiency than one seeded with aerobic excess sludge after cation polyacrylamide flocculation-concentration and dehydration.The TCOD removed was 470.8 mg/L in pilot scale EGSB reactor at short hydraulic retention time of 15 h.SEM of sludge granules showed that the microbiological structure of the sludge from different sources showed some differences.SEM demonstrated that Methanobacterium sp.was present in the granules of pilot-scale EGSB and the granular sludge produced by landfill contained a mixture of anaerobic/anoxic organisms in abundance.The particle size distribution in EGSB demonstrated that using anaerobic granular sludge produced by sanitary landfill as the seeding granular sludge was feasible.
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