Safdar Ali

Gamma-ray activity and dose rate of brick samples from some areas of North West Frontier Province (NWFP), Pakistan

It is important to measure natural radioactivity due to gamma-rays from building materials and consequently to determine the dose rate from these materials. This helps to implement precautionary measures whenever the dose rate is found to be above the recommended limits. A knowledge of gamma radioactivity is required by the building construction association to adopt preventive measures to mitigate or minimize the harmful effects of ionizing radiation. The aim of this work was to measure the gamma activity due to 226Ra, 232Th and 40K in bricks from the Peshawar, Nowshera and Mardan districts of NWFP of Pakistan. The radiological doses to the occupants from the brick floor of a wooden house were calculated. The average gamma dose equivalent rate was calculated to be 0.14 mSv per year, which is well below the external gamma dose limit of 0.46 mSv per year as given in UNSCEAR [2].

Determination of equilibrium factor between radon and its progeny using surface barrier detector for various shapes of passive radon dosimeters

Abstract In the field of radon dosimetry, it is customary to measure radon ( 222 Rn) concentration while potential health hazard is due to the radon short-lived progeny. When radon is in secular equilibrium, the measured activity of radon equals the activity of radons progeny. However, in practical cases an inequilibrium between radon and its progeny exists which is measured in terms of the equilibrium factor. To determine the equilibrium factor between radon and its progeny in a closed environment various shapes of passive dosimeters based upon solid state nuclear track detectors (SSNTDs) are employed. In order to observe the dependence of equilibrium factor upon shapes or effective volumes, experiments have been performed replacing the SSNTDs with a surface barrier detector in Karlsruhe Diffusion Chamber (KDC), Pen-type and Box-type dosimeters. Using the collected alpha spectra, the equilibrium factor has been determined for a radon-air mixture in a custom designed radon chamber simulating a closed environment of a room. The results show that the radon equilibrium factor is about 0.20 for different shapes of dosimeters studied in this research. It is concluded that the determination of equilibrium factor between radon and its progeny does not depend upon effective volume or shape of the passive dosimeters using alpha spectroscopic data acquired by surface barrier detector.

Measurements of radionuclides in coal samples from two provinces of Pakistan and computation of External γ ray dose rate in coal mines

Abstract The radionuclides present in coal may not only be a health hazard for the coal miners but also may be a threat to the general population if these radionuclides disperse in the environment. This research has been conducted to quantify the radionuclides present in the coal samples from various coal-mines of two provinces, Punjab and Balochistan of Pakistan. In this regard, a high-purity Ge-detector-based γ-spectrometer was used. The maximum activity concentrations for 226Ra, 232Th and 40K were found to be 31·4±3·0, 32·7±3·2 and 21·4±5·0xa0Bqxa0kg-1, respectively. A theoretical model to compute external γ-ray dose rate from a coal-mine surface was developed. The Monte Carlo simulation was employed to compute the required mass attenuation coefficients corresponding to the various γ-ray energies from 226Ra, 232Th, their progeny and 40K present in the coal samples. In addition, the effective thickness of coal slab for self-absorption was also computed using the Monte Carlo Neutron Photon (MCNP) transport code. The computed external γ-ray dose rate has been found to be much below the dose ratelimits for occupational persons as well as for the general population.

Estimation of radon concentrations in coal mines using a hybrid technique calibration curve

The results of epidemiological studies in various countries show that radon and its progeny cause carcinogenic effects on mine workers. Therefore, it becomes of paramount importance to monitor radon concentrations and consequently determine the radon dose rates in coal mines for the protection of coal miners. A new calibration curve was obtained for radon concentration estimation using hybrid techniques. A calibration curve was generated using 226Ra activity concentration measured by a HPGe detector-based gamma-ray spectrometer versus alpha-track-density rate due to radon and its progeny on CR-39 track detector. Using the slope of the experimentally determined curve in the units of Becqueral per kilogram (Bq kg-1) per unit alpha-track-density per hour (cm-2 h-1), radon concentrations (Bq m-3) were estimated using coal samples from various coal mines in two provinces of Pakistan, Punjab and Balochistan. Consequently, radon dose rates were computed in the simulated environment of the coal mines. Results of these computations may be considered with a caveat that the method developed in this paper provides only a screening method to indicate the radon dose in coal mines. It has been shown that the actual measurements of radon concentrations in the coal mines are in agreement with the estimated radon concentrations using the hybrid-technique calibration curve.

Improvements in wheat productivity and soil quality can accomplish by co-application of biochars and chemical fertilizers

The beneficial role of biochar is evident in most of infertile soils, however this is argued that increment in crop yield owing to biochar application does not always achieve in cultivated/fertile soils. The nutrient biochar believed to enhance crop yield and soil fertility than structural biochar that may offset the positive effect of chemical fertilizer on crop performance but improves soil structural properties. Therefore, we investigated the effect of biochars [produced from nutrient rich feedstocks like poultry manure (PMB) and farmyard manure (FMB) and structural feedstocks such as wood chips (WCB) and kitchen waste (KWB)], and chemical fertilizers (CF) when applied alone or in combination on soil chemical properties, wheat growth, yield and nitrogen uptake in a cultivated clay loam soil. Sole biochar treatments increased the total carbon and mineral nitrogen content that were 21 and 106% higher, respectively compared to control after 128days (P<0.001). Contrarily, sole biochars application did not increase wheat biological yield and N uptake compared to control (P>0.05) except PMB, the nutrient biochar (P<0.05). Compared to control, grain yield was 6 and 12% lower in WCB and FMB, respectively but not differed from KWB, PMB or WCB-CF. Conversely, co-application of biochars and CF treatments increased crop biological yield but the increment was the highest in nutrient biochars FMB or PMB (29 or 26%), than structural biochars WCB and KWB (15 and 13%), respectively (P<0.05). For N uptake, this increment varies between 16 and 27% and again nutrient biochar has significantly higher N uptake than structural biochars. Hence, nutrient biochars (i.e. PMB) benefited the soil fertility and crop productivity more than structural biochars. Therefore, for immediate crop benefits, it is recommended to use nutrient biochar alone or in combination with chemical fertilizer. Such practice will improve crop performance and the quality of cultivated soil.

Assessment of Different Exotic Sunflower Hybrids for their Agro-Ecological Adaptability

S is one of the world’s chief cultivated oil crops next to soybean, oil palm and rapeseed (Fernandez-Martinez et al., 2004). Due to its higher adaptability in different climatic conditions and high return per unit area sunflower has become most vital oil growing crop. The country produced a total of 32.6 million tons from about 23.4 million hectares area (USDA-October, 2009). In Pakistan area under sunflower in 2008-09 was 376 thousand hectares with production of 5.98 m tons seed and 227 thousand tons oil (Anon., 2010). Its average yield in Pakistan is 1520 kg/ ha. Its potential yield on research level is > 4500 kg/ha and potential yield on progressive farmer fields is 3800kg/ha. The one of the reasons for minimum seed yield of exotic sunflower hybrids is their non-adaptability in Pakistan (Bkhat et al., 2006). It is Abstract | Sunflower (Helianthus annuus L.) is an important oil seed crop in Pakistan having the potential of bridging gap between production and consumption of edible oil in the country. The experiment was conducted at National Agriculture Research Center (NARC) Islamabad, Pakistan, during August to December, 2016, to evaluate different exotic sunflower hybrids for their performance and adaptability in the field area of NARC. Twelve sunflower hybrids including one check i.e. SF-16013, SF-16007, SF-16010, SF-16005, SF-16006, SF-16002, SF-16008, SF-16004, SF-16011, SF16003, SF-160011, Hysun-33 were studied in the experiment. The experiments were carried out in Randomized Complete Block Design with three replications. The distance between adjacent rows was 75 cm while the distance between plants to plant was 30 cm. The seed was sown in the first week of August. The following parameters were studied in the experiment i.e. days to flower initiation, days to flower completion, plant height, days to maturity, stem diameter, head diameter, number of leaves, 1000 seed weight and seed yield per hectare. Quality parameters were consisted upon oil content (%), protein content (%), and fatty acid profile. The results showed that significantly highest seed yield (2187.3) kg ha-1 was produced by SF 16003 followed by SF16010 and SF 16002 having (2016.2) kg ha-1 and (1888.2) kg ha-1 seed yield respectively. The Cluster analysis also determined SF 16003 as best hybrid which was at a very close distance from the group of SF16010 and SF 16002. Qasim Iqbal1, Safdar Ali1*, Muhammad Naveed Tahir1, Obaidullah Shafique1, Bashir Ahmed Khan2, Ijaz Ahmad3 and Ihsanullah Khan4