[en] Changes in the effects of gamma irradiation (10 to 110 Kr) with gibberellic acid (GA/sub 3/) for peroxidase activity, in relation to early days of seedling's growth in Kabulic chickpea cultivar, Noor-91, were evaluated. Stimulation in peroxidase activity over control was recorded at all the irradiation treatments from 3rd to 8th day of seedling's development. Increase in peroxidase activity at 10 and 20 Kr was due to the increase in metabolic activity, while higher doses of gamma radiation account for the damaging action and production of peroxy radicals. However, stimulation in fresh weight was observed only at 10 Kr of gamma irradiation. Postmutagenic application of Ga/sub 3/ protect the seedlings from radiation injury, by increasing the peroxides activity, and increased the fresh weight of chickpea seedlings. (author)

[en] The genotype-environment interaction and stability of twenty oat (Avena sativa L) cultivars were determined across three locations for two years, for green-fodder yield and its components. Significant differences were observed among varieties for green-fodder yield and its components. Significant differences were also observed for their genotype x environment interaction, except that for plant-height between locations. Three stability parameters, mean (x), regression coefficient (bi) and deviation from linear response (S/sup 2/ d), were computed. Oat cultivar Scott produced the highest green-fodder yield of 69.35 t/h and showed higher response to environmental changes (bi = 1.45) with non-significant S/sup 2/ d of 12.47, showing comparative stability for green fodder yield at three locations. The least S/sup 2/d values of -9.62, -4.78 and -3.50 were shown by cultivars Swan, No. 616 and Fulgrain, respectively, showing the stability for green-fodder yield. Most of the cultivars showed higher response to environmental changes, corresponding to their regression-coefficient values for plant height and leaf area. S-141 produced the maximum plant height of 136.40 cm, under unfavorable environmental conditions (bi = 0.35), but showed unstability for plant height. Comparative stability for leaf-area was observed for most of the cultivars corresponding to their least S/sup 2/d values. Cultivar Cuscade produced maximum leaf-area of 128.37 cm/sup 2/, under favorable environments bi = 2.33, and was unstable for leaf area, S/sup 2/d of 870.70. (author)

[en] Floods are one of the most frequent natural hazards faced by human kind. Their prevention and mitigation is a great challenge for both technical and administrative authorities. Numerical modeling has emerged as an important analytical and diagnostic tool for modeling floods in urban environment. The paper presents a numerical model, Rubar20, and explains the numerical technique used to solve the depth-averaged equations. The model inputs are topography and boundary-conditions at entry and exit locations of the flood-wave. The output consists of a map of water-depths and two components of flow-velocity at progressive times for the .flooded zone. A case study is also presented, which simulates a real flood in the southern French city of Nimes. A comparison of measured and computed water levels shows minor differences, due to time-lag between predicted and physically measured depths and because of in-sufficient topographical data. However, the extents of flooded area and the flood dynamics are simulated correctly. (author)

[en] Part-1 of this series dealt with Wind-Energy Prospects in Pakistan. This second part gives a brief account Mini/Micro Hydro-Power Plants in Pakistan. Hydropower is well-known throughout the world and currently contributes 6-7% of total world energy-production and 20% of total world electricity generation. Most of the hydro-plants are usually designed for higher generation capacity than that which could be needed to utilize the average water-flows. Small hydro-plants are another potential source of energy among the non-conventional energy sources, which can reduce the load on conventional-energy production. Small hydropower technology is today a mature and proven technology. Civil works and installation of equipment involve simple process, which offer good opportunity to local people for employment and use locally available materials Nevertheless a small decentralized hydel plant, based on natural waterfalls is a very desirable option for geographically remote, but naturally suitable locations which are otherwise far from the national physical infrastructure. The development of Mini/Micro hydel stations in these areas, with isolated, thinly clustered, population, is a very appropriate solution to meet power-needs of such areas for lighting as well as cottage industry. The unique feature of these installations is the participation of local community to the optimum extent. The entire civil works, the intake system, power channel, forebay, penstock and power house building, as well as labour is provided by the inhabitants voluntarily. While maximum use is made of stone, with minimum use of cement, the generator, distribution wires, etc., need to be arranged from the market. The turbine is manufactured using indigenous materials. The installation-cost per KW is relatively low i.e. Rs. 25,000/- as compared to large-scale installations. There could of course be variations, in the installation-cost, depending on the market prices of the material. (author)

[en] The Indian model of the biogas digester has been introduced in the country during the last three decades, whereas the Chinese dome-type design could not be introduced due to the skills required for construction of this digester. The other problem associated with Chinese dome-type digester is that large quantities of solid waste are needed to fill the digester. The Chinese dome-type digester constructed on experimental basis could not perform satisfactorily. The Indian Model, although popular in the country, is not environment friendly and is of high cost, both in terms of capital investment and 0 and M. It creates quite dirty environment around the digester due to the free movement of slurry. It also creates problems of mosquitoes, as the environment. is conducive for their breeding. Taking into consideration, these limitations, design of polyethylene capsule-type digester (with black carbon and UV stabilizers) was developed, using water tanks normally constructed for domestic water storage by the local plastic companies. Modification was made in the PE water tank and one of the local companies collaborated to manufacture the capsule-type digester. Solid waste is introduced from the top, whereas the slurry can be disposed from the bottom through a controlled valve. Thus input of solid waste and slurry-disposal is now within the choice of the owner. The slurry can be disposed into a tank, where it can be composted to reduce the pH, before its use for agriculture. The PE capsule-type black-color digester is also attractive for increasing the temperature of the digester due to black body absorption. The production of gas during summer season might take a few days, whereas additional greenhouse effect during winter can raise the temperature by 10 degree C. Hence, this digester is more suitable for cooler regions where the Indian model is not successful. The design is modular in nature; therefore linking additional modules in series can increase the capacity of biogas production. The other prevailing problem with the commonly used biogas digester is that the gas pressure is low. In the PE Capsule-type digester, gas is stored in the used rubber tubes, where putting load on the tubes can easily increase the gas pressure. Thus pressure of the gas can be maintained very effectively. Adding inoculums of the methogenic bacteria can increase the production of the gas. Lime has to be added to increase the pH, because methogenic bacteria are effective in neutral to alkaline environment, instead of the acidic environment, which is commonly experienced after adding solid waste into the digester. Temperature is another important parameter for enhancing productivity of biogas. The system is cost-effective, as the total cost is around Rs. 10,000 for a unit producing gas to light a single burner for 40-100 hours. The technology transfer will be easy, as the private plastic companies can market such systems more effectively than the public sector. Four modules of this system more can be installed with the cost of one Indian-type model. (author)

[en] Xanthate-type collectors reported for the upgradation of Chalcopyrite ore of North Waziristan area were studied and a new technique was developed, in which -two collectors were used (composite collectors) in the bulk-stage process of froth-flotation to achieve metallurgical grade with maximum recovery. The collectors studied were thiol-type surfactants, such as sodium ethyl xanthate (NaEX), sodium propyl xanthate (NaPX), sodium butyl xanthate (NaBX) and sodium Amyl xanthate (NaAX). Mixed collectors examined were in the varying dosage ratio of (0-100:100-0) through the combination of(i) sodium ethyl xanthate with sodium propyl xanthate, sodium ethyl xanthate with sodium butyl xanthate, sodium ethyl xanthate with sodium amyl xanthate, (ii) sodium propyl xanthate with sodium butyl xanthate, sodium propyl xanthate with sodium amyl xanthate and (iii) sodium butyl xanthate with sodium amyl xanthate. All the remaining flotation parameters were kept constant during the various flotation tests. The results were compared and the conclusions were drawn that the optimum grade in the concentrate was obtained with a mixture having a ratio of 4: 1 with sodium ethyl xanthate and sodium butyl xanthate. Recovery of copper content in the concentrate was achieved with ratio of 2:3 with sodium butyl xanthate and sodium amyl xanthate. (author)

[en] In this paper, the problem of reconfiguration of the distribution-network, under normal operation, to reduce active losses and to balance loads in the system, is considered along with other objectives. The network reconfiguration consists of modifying the topology of the system. In this process, the nodes can be energized through different paths, through interconnection, with interconnection of nodes belonging to same feeder. Usually, distribution-systems operate with a radial topological structure; consequently the opening and closing of sectionalizers must be made, with consideration of this constraint. The problem consists in determining the best optimal route, to reduce losses and to balance the load of the system without infringing operational and topological constraints. The objective reduction of energy-losses, improvement in the voltage-profile, load balancing, power-factor improvement, removal of road hazards and finding the optimal route of the feeder, keeping in view various constraints like, cost, right-of-way problem, public inconvenience, earth topology, etc. Hybrid approach is used to achieve these multiple objectives. Different radial configurations were generated, improving the objectives of the network. Energy-Loss Reduction (ELR) Program was used to analyze the existing and proposed configurations. The results are realistic and feasible. There is reduction of 5% in Technical losses, i.e. from 8% to 3%. Annual saving is 80, 27, 41.3 KWH units, which come out to Rs. 2.4 million per annum, approximately. (author)

[en] Chilli (Capsicum annuum L.) belongs to the family Solanaceae is one of the most important cash crop of the southern parts of Pakistan. Capsicum is cultivated on a large scale in a lower region of Sindh, Pakistan. It is an important and profitable crop of Pakistan. Several biotic and abiotic stresses affect the productivity of chilli crop. It is infected by a number of diseases particularly soil-borne diseases. Surveys of soil-borne fungal diseases associated with chilli crop in different areas of lower Sindh, including, Hyderabad, Tando Allahyar, Mirpurkhas, Umerkot, Kunri, Samaro, Kot Ghulam uhammad and Digri, were conducted, and chilli plants showing symptoms of wilting were collected. A number of soil-borne root infecting fungi were isolated and identified, such as, Fusarium oxysporum, F. solani, Macrophomina phaseolina, Phytophthora capsici, Pythium sp., and Rhizoctonia solani, from collected disease plants. It was observed that all the major varieties of chillies (i.e., Sanam, Talhari, Ghotaki, Mexi), growing in lower Sindh, were highly susceptible to these fungi. The main objectives of the study were to examine the effectiveness of chitin for the management of soil-borne diseases of chilli plant by different methods, i.e., soil amendment and transplant root dip method. Results indicated that of the two methods, the soil amendment method was more effective while transplant root dip method was less effective. (author)

[en] There has been a recent resurgent interest in microalgae as an oil producer for biofuel applications. An adequate supply of nutrients and carbon dioxide enables algae to successfully transform light energy of the sun into energy - rich chemical compounds through photosynthesis. A strain with high lipids, successfully grown and harvested, could provide oil for most of our process by volume, which would then provide the most profitable output. Significant advances have also been made in upstream processing to generate cellular biomass and oil. However, the process of extracting and purifying of oil from algae continues to prove a significant challenge in producing both microalgae bioproducts and biofuel, as the oil extraction from algae is relatively energy-intensive and expensive. The aim of this review is to focus on different harvesting and extraction processes of algae for biodiesel production reported within the last decade. (author)

[en] Exogenous application of plant growth regulators is an important element in modern day agricultural production technology. The precursor of auxin, L-Tryptophan (L-TRP), is the most important plant growth regulator and is physiologically very vital in modelling plant growth and development. To evaluate the effect of L-TRP on chickpea plant weight and pod weight, a field experiment was conducted during 2003, employing randomised complete block design under rain-fed conditions. The treatments were L-TRP at the rate 10 -2 M, L-TRP at the rate 10-3 M, L-TRP at the rate 10/sup -4/ M and a control. Analysis showed that L-TRP at the rate 10/sup -3/M had a significant effect on plant and pod weight, suggesting the additional effect of plant growth promoting factor provided by auxin production. The L-TRP improved the crop vegetative and reproductive growth that consequently increases pod weight. (author)