University of PeshawarKhyber Pakhtunkhwa

Electronics, Pakistan

University of PeshawarKhyber Pakhtunkhwa

Electronics, Pakistan
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Bibi S.,University of PeshawarKhyber Pakhtunkhwa | Alam K.,University of PeshawarKhyber Pakhtunkhwa | Chishtie F.,Pakistan Academy of science | Bibi H.,University of PeshawarKhyber Pakhtunkhwa | Rahman S.,University of Karachi
Journal of Atmospheric and Solar-Terrestrial Physics | Year: 2017

Black Carbon (BC) mass concentration was measured continuously for every five-minute interval with ground-based Aethalometer at an urban site in Karachi for the period from 2006 to 2008. In this study, the temporal (diurnal, monthly and seasonal) variations of BC and its relationship with meteorological variables were analyzed. Monthly averaged concentrations of BC ranged from 2.2 to 12.5 µg/m3, with maximum in the month of January 2007 and minimum in the month of June 2006. BC showed higher concentrations during the months of January, February and November while lower during the months of May, June, July and August throughout the years. It also displayed comparatively high concentrations during winter and postmonsoon, while moderate during premonsoon and low during summer. Diurnal analysis of BC concentration showed sharp peaks between 07:00 and 09:00 LST and again around 22:00 during all the months. Moreover, the relationship between BC concentration and meteorological variables such as Temperature (Temp), Relative Humidity (RH), Wind Speed (WS), Visibility (VIS) and RainFall (RF) was found and it was observed that BC concentration showed an inverse relationship with all these meteorological variables. Finally, the analysis of the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) cluster trajectories revealed that almost all the clusters were originating from southwest of the study site. © 2017 Elsevier Ltd

Bibi S.,University of PeshawarKhyber Pakhtunkhwa | Alam K.,University of PeshawarKhyber Pakhtunkhwa | Chishtie F.,Pakistan Academy of science | Bibi H.,University of PeshawarKhyber Pakhtunkhwa | Rahman S.,University of Karachi
Science of the Total Environment | Year: 2017

With observations of black carbon (BC) aerosol concentrations, optical and radiative properties were obtained over the urban city of Karachi during the period of March 2006–December 2008. BC concentrations were continuously measured using an Aethalometer, while optical and radiative properties were estimated through the Optical Properties of Aerosols and Clouds (OPAC) and Santa Barbra DISORT Atmospheric Radiative Transfer (SBDART) models, respectively. For the study period, the measured BC concentrations were higher during January, February and November, while lower during May, June, July and August. A maximum peak value was observed during January 2007 while the minimum value was observed during June 2006. The Short Wave (SW) BC Aerosol Radiative Forcing (ARF) both at Top of the Atmosphere (ToA) and within ATMOSphere (ATMOS) were positive during all the months, whereas negative SW BC ARF was found at the SurFaCe (SFC). Overall, SW BC ARF was higher during January, February and November, while relatively lower ARF was found during May, June, July and August. Conversely, the Long Wave (LW) BC ARF at ToA and SFC remained positive, whereas within ATMOS it shifted towards positive values (heating effect) during June–August. Finally, the net (SW + LW) BC ARF were found to be positive at ToA and in ATMOS, while negative at SFC. Moreover, a systematic increase in Atmospheric Heating Rate (AHR) was found during October to January. Additionally, we found highest correlation between Absorption Aerosol Optical Depth (AODabs) and SW BC ARF within ATMOS followed by SFC and ToA. Overall, the contribution of BC to the total ARF was found to greater than 84% for the whole observational period while contributing up to 93% during January 2007. © 2017 Elsevier B.V.

Shah J.,University of PeshawarKhyber Pakhtunkhwa | Rasul Jan M.,University of PeshawarKhyber Pakhtunkhwa | Zeeshan M.,University of PeshawarKhyber Pakhtunkhwa | Imran M.,University of PeshawarKhyber Pakhtunkhwa
Applied Clay Science | Year: 2017

The applicability of surfactant modified fuller's earth (SMFE) for removing 2,4-dichlorophenol (2,4-DCP) from water has been investigated through batch sorption process. Fuller's earth was treated with sodium dodecyl sulphate (SDS) for conversion of fuller's earth into surfactant modified fuller's earth. The influence of pH, agitation time, sorbent dose, temperature and initial concentration of 2,4-DCP were investigated. A strong dependence of the sorption capacity on pH was observed, the capacity increased as the pH value decreased. The sodium dodecyl sulphate increased the hydrophobicity of the sorbent and provided particular affinity for 2,4-DCP molecules. The SMFE showed high efficiency towards 2,4-DCP and > 97% removal was achieved from an initial concentration of 20 mg/L at 100 °C using pH 3. The kinetics of the sorption process was described by a pseudo-second-order kinetic model. The mechanism of sorption kinetics was investigated using intraparticle diffusion model. The sorption isotherm was consistent with the Langmuir sorption isotherm and maximum monolayer capacity of the SMFE was found to be 126.58 mg/g at room temperature. The mean adsorption energy (E) value 18.25 kJ/mol indicated chemical sorption and endothermic sorption process. © 2017 Elsevier B.V.

Khan R.,Quaid-i-Azam University | Ullah A.,University of PeshawarKhyber Pakhtunkhwa | Khan B.,University of PeshawarKhyber Pakhtunkhwa | Khan S.M.,Quaid-i-Azam University | Rashid A.,University of PeshawarKhyber Pakhtunkhwa
Pakistan Journal of Botany | Year: 2017

Six (6) species of three tribes Arundineae (Arundo donax L. & Phragmites karka (Retz.) Trin. ex Steud.), Aristideae (Aristida adscensionis L. & Aristida cyanantha Nees ex Steud.) and Chlorideae (Cynodon dactylon (Linn.) Pers.& Tetrapogon villosus Desf.) were investigated for their foliar micro-morphological variation and its taxonomic significance through Light and Scanning Electron microscope. The three tribes has a great diversity in the micro-morphological features i.e. stomatal type number, size, shape, stomatal density (SD), silica bodies, macrohairs, micro hairs, epidermal cell number, epidermal cell density (ECD), subsidiary cells, prickles, hooks, papillae, short and long cells on both abaxial and adaxial surfaces. In species of Arundineae paracytic stomata were observed, in Aristideae tetracytic type of stomata were observed, while in Chlorideae both paracytic and teracytic stomata were seen. The Arundineae has maximum stomatal number (Mean 21.4 to 46.2) and epidermal cell (Mean 51.6 to 77.2). These foliar micro-morphological characters were found significant in the delimitation and systematics of these species and can be used as tool in the identification and assessment of taxonomic problems at species and tribe levels. © 2017, Pakistan Botanical Society. All rights reserved.

Hassan A.,University of PeshawarKhyber Pakhtunkhwa | Paganin V.A.,University of Sao Paulo | Ticianelli E.A.,University of Sao Paulo
Journal of Power Sources | Year: 2016

The CO tolerance mechanism and the stability of carbon supported PtW electrocatalysts are evaluated in the anode of a proton exchange membrane fuel cell (PEMFC) at two different temperatures. The electrocatalysts are characterized by energy dispersive spectroscopy, X-ray diffraction, and transmission electron spectroscopy. Employed electrochemical techniques include cyclic voltammetry, CO stripping, fuel cell polarization, and online mass spectrometry. At a cell temperature of 85 °C, the PtW/C catalyst shows higher CO tolerance compared to Pt/C due an electronic effect of WOx in the Pt 5d band, which reduces the CO adsorption. An increase in hydrogen oxidation activity in the presence of CO is observed for both the catalysts at a higher temperature, due to the decrease of the Pt-CO coverage. A reduction in the current densities occurs for the PtW/C catalyst in both polarization curves and cyclic voltammograms after 5000 cycles of the anode in the range of 0.1–0.7 V vs. RHE at 50 mVs−1. This decrease in performance is assigned to the dissolution of W, with a consequent increase in the membrane resistivity. However, the observed decline of performance is small either in the presence of pure H2 or in the presence of H2/CO. © 2016 Elsevier B.V.

Midrarullah,University of PeshawarKhyber Pakhtunkhwa | Midrarullah,Shaheed Benazir Bhutto University | Ahmed B.,University of PeshawarKhyber Pakhtunkhwa
Pakistan Journal of Botany | Year: 2015

Field experiment was performed to investigate the growth promoting activities of plant growth promoting rhizobacteria (PGPR) on different growth parameters of maize variety ‘Pahari’. Three bacterial strains Azospirillum brasilense strain R1, Azospirillum lipoferum strain RSWT1 and Pseudomonas strain Ky1 were used to inoculate maize. Plant growth promotion was observed in all inoculated treatments over un-inoculated control which was evident from increase in plant height, number of grains/ear, thousand grain weight and biological yield. Azospirillum lipoferum strain RSWT1 was more effective in plant growth promotion than other strains. The inoculation with Azospirillum lipoferum strain RSWT1 evidenced increase in plant height (8.82%), number of ear/plant (35%), ear length (27%), ear weight (19.4%) and thousand grains weight (11.8%) compared to control treatment. Similarly, Inoculation with Azospirillum brasilense strain R1 result increased in plant height (6.5%), number of ears/plant (45.9%), ear length (23.7%), ear weight (17.25%) and thousand grain yield (9.68%) as compared to control treatments. Higher biological yield (9210 kg/ha) was produced when treatment was done with Azospirillum lipoferum strain RSWT1 followed by treatment with Azospirillum brasilense strain R1 (8960 kg/ha). The study revealed that beneficial strains of PGPR can be used as biofertilizer for maize. © 2015, Pakistan Botanical Society. All rights Reserved.

Ullah S.,Quaid-i-Azam University | Begum M.,University of Malakand | Dhama K.,Indian Veterinary Research Institute | Ahmad S.,University of Malakand | And 2 more authors.
Asian Journal of Animal and Veterinary Advances | Year: 2016

The current study was aimed to investigate the genotoxic effect of an organophosphate pesticide malathion in the gills of a freshwater teleost rohu, Labeo rohita using alkaline Single Cell Gel Electrophoresis (SCGE)/comet assay. The 96 h LC50 of malathion was estimated for rohu in a semi-static system and was found to be 5 µg L-1. Specimens of rohu were exposed to LC50 of malathion. Gill tissues were sampled after 24, 48, 72 and 96 h of exposure. DNA damage was evaluated by studying different indices, including tail length (µm), percentage of DNA in tail, tail moment and olive tail moment using TriTek CometScore™. A linear relation was observed between exposure time and DNA damage in the gill cells. The current study revealed malathion as a potent inducer of DNA damage and comet assay as a reliable and sensitive assay for investigating and detecting DNA damage in vivo, induced in fish by genotoxic pesticides. In order to conserve the vanishing populations of rohu in natural aquatic bodies across the country, indiscriminate use of genotoxic pesticides such as malathion should be minimized. ©2016 Sana Ullah et al.

Ali N.,University of Technology Malaysia | Ajmal S.,University of PeshawarKhyber Pakhtunkhwa | Shah M.,University of PeshawarKhyber Pakhtunkhwa | Ahmed R.,University of Technology Malaysia | And 2 more authors.
Chalcogenide Letters | Year: 2014

Antimony doped tin sulphide thin films were prepared on glass substrate from SnS and Sb2S3 powder by thermal evaporation techniques. The thin films were annealed in argon gas at 250°C for 30 minutes. The films were characterized by X-ray diffraction (XRD), optical microscopy, optical absorption, photoconductivity, and hot-probe techniques. The XRD studies revealed that the annealed films are polycrystalline. The band gap was found to be in the range 2.2-2.6eV along with p-type conductivity. The value of the absorption coefficient is found to be higher than 105 cm-1. © 2014, National Institute R and D of Materials Physics. All right reserved.

Khan M.A.,University of PeshawarKhyber Pakhtunkhwa | Ullah A.,University of PeshawarKhyber Pakhtunkhwa | Rashid A.,University of PeshawarKhyber Pakhtunkhwa
Pakistan Journal of Botany | Year: 2015

The present research documents the use of ethnoveterinary medicine for curing various animal diseases. Most of the animal diseases are treated by using the local herbal medicines extracted from the plants. Survey was carried out and information was collected from the locals and farmers to identify the traditional remedies. For extraction of local knowledge about Ethnoveterinary Plants (EVPs) questionnaire method was adopted. A total of 27 animal diseases were reported, and it was concluded that diseases like milk deficiency, foot and mouth, diarrhea, worm infestation and mastitis are the most common diseases. A total of 83 plants within 44 families of which 1 species of fungi and gymnosperm and 81 species of angiosperm were identified for the treatment of various animal diseases. Most frequently plant parts used for ethnoveterinary medicine are fruit 24(28.57%), seed 18(21.42%), leaf 15(17.85), rhizome 7(8.33), bark 6(7.14), seed oil 5(5.95), whole plant 4(4.76) root 3(3.57), stem and bulb 2(2.380) and flower 1(1.19). The most frequent administration is oral followed by dermal. Information regarding botanical sources, family, local name, part used, method of preparation and application of these crude drugs were investigated in this study. The plant material is used singly or in combination. It is noted that 34 plants were used to treat more than one disease, while 49 plants are used to cure 1 particular disease. The local inhabitants use leaves, fruits, seeds, rhizomes and bulbs for preparation of various remedies and these remedies are used orally and topically. © 2015, Pakistan Botanical Society. All rights Reserved.

Bibi H.,University of PeshawarKhyber Pakhtunkhwa | Alam K.,University of PeshawarKhyber Pakhtunkhwa | Bibi S.,University of PeshawarKhyber Pakhtunkhwa
Atmospheric Research | Year: 2016

Discrimination of aerosol types is essential over the Indo-Gangetic plain (IGP) because several aerosol types originate from different sources having different atmospheric impacts. In this paper, we analyzed a seasonal discrimination of aerosol types by multiple clustering techniques using AERosol RObotic NETwork (AERONET) datasets for the period 2007–2013 over Karachi, Lahore, Jaipur and Kanpur. We discriminated the aerosols into three major types; dust, biomass burning and urban/industrial. The discrimination was carried out by analyzing different aerosol optical properties such as Aerosol Optical Depth (AOD), Angstrom Exponent (AE), Extinction Angstrom Exponent (EAE), Abortion Angstrom Exponent (AAE), Single Scattering Albedo (SSA) and Real Refractive Index (RRI) and their interrelationship to investigate the dominant aerosol types and to examine the variation in their seasonal distribution. The results revealed that during summer and pre-monsoon, dust aerosols were dominant while during winter and post-monsoon prevailing aerosols were biomass burning and urban industrial, and the mixed type of aerosols were present in all seasons. These types of aerosol discriminated from AERONET were in good agreement with CALIPSO (the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) measurement. © 2016 Elsevier B.V.

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