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21.
Hazard and operability (HAZOP) studies constitute an essential step in the risk analysis of any chemical process industry and involve systematic identification of every conceivable abnormal process deviation, its causes and abnormal consequences. These authors have recently proposed optHAZOP as an alternative procedure for conducting HAZOP studies in a shorter span of time than taken by conventional HAZOP procedure, with greater accuracy and effectiveness [Khan, F. I. and Abassi, S. A., optHAZOP. An effective and efficient technique for hazard identification and assessment Journal of Loss Prevention in the Process Industries, 1997, 10, 191–204]. optHAZOP consists of several steps, the most crucial one requires use of a knowledge-based software tool which would significantly reduce the requirement of expert man-hours and speed up the work of the study team. TOPHAZOP (Tool for OPTmizing HAZOP) has been developed to fulfil this need.

The TOPHAZOP knowledge-base consists of two main branches: process-specific and general. The TOPHAZOP framework allows these two branches to interact during the analysis to address the process-specific aspects of HAZOP analysis while maintaining the generality of the system. The system is open-ended and modular in structure to make easy implementation and/or expansion of knowledge. The important features of TOPHAZOP and its performance on an industrial case study are described.  相似文献   

22.
A multi-objective optimisation approach to water management   总被引:3,自引:0,他引:3  
The management of river basins is complex especially when decisions about environmental flows are considered in addition to those concerning urban and agricultural water demand. The solution to these complex decision problems requires the use of mathematical techniques that are formulated to take into account conflicting objectives. Many optimization models exist for water management systems but there is a knowledge gap in linking bio-economic objectives with the optimum use of all water resources under conflicting demands. The efficient operation and management of a network of nodes comprising storages, canals, river reaches and irrigation districts under environmental flow constraints is challenging. Minimization of risks associated with agricultural production requires accounting for uncertainty involved with climate, environmental policy and markets. Markets and economic criteria determine what crops farmers would like to grow with subsequent effect on water resources and the environment. Due to conflicts between multiple goal requirements and the competing water demands of different sectors, a multi-criteria decision-making (MCDM) framework was developed to analyze production targets under physical, biological, economic and environmental constraints. This approach is described by analyzing the conflicts that may arise between profitability, variable costs of production and pumping of groundwater for a hypothetical irrigation area.  相似文献   
23.
Cattle (Bos taurus) producers can replace a part of the traditional diet of barley (Hordeum vulgare L.) grain/silage with sunflower (Helianthus annus L.) seeds or canola meal (Brassica napus L.)/oil to enhance conjugated linoleic acids (CLA) content in milk and meat for its positive health benefits. The objective of this study is to investigate the effects of feeding sunflower or canola to finishing steers on cattle manure chemical properties and volatile fatty acid (VFA) content. The control diet contained 84% rolled barley and 15% barley silage, which provided only 2.6% lipid. The other six treatments had 6.6 to 8.6% lipid delivered from sources such as hay, sunflower seed (SS), canola meal/oil, and SS forage pellets. Manure samples (a mixture of cattle urine, feces, and woodchip bedding materials) were collected and analyzed after cattle had been on these diets for 113 d. The dietary source and level of lipid had no effect on organic N and nitrate N content in manure, but significantly affected ammonia N and VFA. Inclusion of SS forage pellets, hay, or canola meal/oil in cattle diets had no significant impact on manure characteristics, but SS significantly reduced the pH and increased propionic, isobutyric, and isovaleric content. In addition, N loss after excretion (mainly from urine N) increases with the pH and N levels in both feed and manure. The combination of SS with barley silage resulted in a lower VFA and NH3 content in manure and should be a more attractive option. To better manage N nutrient cycles and reduce NH3 related odor problems, feed and manure pH should be one of the factors to consider when determining feed mix rations.  相似文献   
24.
Titanium dioxide nanoparticles (TiO2 NPs) are widely used for their whiteness and opacity in several applications such as food colorants, drug additives, biomedical ceramic, and implanted biomaterials. Research on the neurobiological response to orally administered TiO2 NPs is still limited. In our study, we investigate the effects of anatase TiO2 NPs on the brain of Wistar rats after oral intake. After daily intragastric administration of anatase TiO2 NPs (5–10 nm) at 0, 50, 100, and 200 mg/kg body weight (BW) for 60 days, the coefficient of the brain, acethylcholinesterase (AChE) activities, the level of interleukin 6 (IL-6), and the expression of glial fibrillary acidic protein (GFAP) were assessed to quantify the brain damage. The results showed that high-dose anatase TiO2 NPs could induce a downregulated level of AChE activities and showed an increase in plasmatic IL-6 level as compared to the control group accompanied by a dose-dependent decrease inter-doses, associated to an increase in the cerebral IL-6 level as a response to a local inflammation in brain. Furthermore, we observed elevated levels of immunoreactivity to GFAP in rat cerebral cortex. We concluded that oral intake of anatase TiO2 NPs can induce neuroinflammation and could be neurotoxic and hazardous to health.  相似文献   
25.
The present study was conducted to investigate the contamination of water, sediments, and fish tissues with heavy metals in river Panjkora at Lower Dir, Khyber Pakhtunkhwa, Pakistan. Water, sediments, and fish (Shizothorax plagiostomus) samples were collected from September 2012 to January 2013 at three different sites (upstream site at Sharigut, sewage site at Timergara, and downstream site at Sadoo) of river Panjkora. The concentrations of heavy metals in water were in the order Zn?>?Cu?≈?Pb?>?Ni?≈?Cd with mean values of 0.30, 0.01, 0.01, 0.0 and 0.0 mg/l, respectively, which were below the maximum permissible limits of WHO for drinking water. In sediments, heavy metals were found in the order Cu?>?Zn?>?Ni?>?Pb?>?Cd with mean concentrations of 50.6, 38.7, 9.3, 8, and 0.4 mg/kg, respectively. Ni and Cd were not found in any fish tissues, but Zn, Cu, and Pb were detected with the mean concentration ranges of 0.04–1.19, 0.03–0.12, and 0.01–0.09 μg/g, respectively. The present study demonstrates that disposal of waste effluents causes a slight increase in the concentration of heavy metals in river Panjkora as revealed by variation in metal concentrations from upstream to downstream site. Sewage disposal was also found to change physicochemical characteristics of Panjkora water. At present, water and fish of river Panjkora are safe for human consumption, but the continuous sewage disposal may create problems in the future.  相似文献   
26.
In this paper, we investigate how mountain communities perceive and adapt to climatic and environmental change. Primary data were collected at community and household level through in-depth interviews, focus group discussions, and quantitative questionnaires covering 210 households in six villages of the West Karakoram (Hundur and Darkut in the Yasin Valley; Hussainabad, Altit, Gulmit, and Shiskat in the Hunza valley of Gilgit-Baltistan). The relevance of the area with respect to our scopes is manifold. First, this is one of the most extreme and remote mountainous areas of the world, characterized by complex and fragile institutional and social fabrics. Second, this region is one of the focal points of research for the hydro-meteo-climatological scientific community, because of its relevance in terms of storage and variability of water resources for the whole Indus basin, and for the presence of conflicting signals of climate change with respect to the neighboring regions. Third, the extreme hardships due to a changing environment, as well as to the volatility of the social and economic conditions are putting great stress on the local population. As isolating climate change as a single driver is often not possible, community perceptions of change are analyzed in the livelihood context and confronted with multi-drivers scenarios affecting the lives of mountain people. We compare the collected perceptions with the available hydro-climatological data, trying to answer some key questions such as: how are communities perceiving, coping with, and adapting to climatic and environmental change? Which are the most resorted adaptation strategies? How is their perception of change influencing the decision to undertake certain adaptive measures?  相似文献   
27.
The complex bio-geochemistry of soil allows pollutant to persist for a longer period of time which further decreased the fertility and natural composition of land. Nickel, an inorganic pollutant, coming from a wide range of industrial and manufacturing units possesses serious threat to soil degradation and crop productivity around the world. The present study was carried to evaluate the combined role of microwave irradiation (MR) and citric acid (CA) on the phytoextraction potential of Brassica napus L. under Ni stress. An initial seed germination test was conducted to select effective time scale of MR exposure. Highest seed germination was observed at exposure of 2.45 GHz frequency for 30 s. Healthy seeds of B. napus L. genotype Faisal Canola (RBN-03060) treated with MR at 2.45 GHz for 30 s were sown in plastic pots filled with 5 kg of soil. Nickel and CA applied exogenously in solution form with different combinations to both MR-treated and untreated B. napus plants. The MR-treated plants showed higher growth, biomass, photosynthetic pigments (Chl a, b, total, and carotenoids) and activities of antioxidant enzymes (SOD, POD, APX, CAT) as compared to untreated plants who showed higher reactive oxygen species (MDA, H2O2) and electrolyte leakage. Increasing Ni concentration significantly decreased the physiological and biochemical attributes of B. napus both in MR-treated and untreated plants. The addition of CA alleviated Ni-induced toxic effects in both MR-treated and untreated plants by improving antioxidant defense system. The degree of Ni stress mitigation was higher in MR-treated plants. The Ni concentration was higher in root, stem, and leaves of MR-treated plants under CA application as compared to untreated plants. The present study concluded that seeds treated with MR before sowing showed higher accumulation and concentration of Ni from soil, and this phenomenon boosted with the application of CA.  相似文献   
28.
29.
This research article demonstrates biodiesel synthesis through the methanolysis of the oily contents (4.02 ± 0.27% w/w on dried basis) of Dictyota dichotoma collected from the coast of Hawksbay, Pakistan. The metal oxides (CaO, MgO, ZnO, and TiO2) used as nanocatalysts were refluxed (5% K2SO4), calcinated (850 °C) and characterized by Atomic Force Microscopy (AFM) which produced 93.2% w/w FAME (biodiesel) at relatively mild condition (5% catalyst, 65 °C, 3 h, 18:1 molar ratio) using CaO. Whereas, MgO, ZnO, and TiO2 produced 92.4%, 72.5%, and 31.8% w/w FAME, respectively at elevated condition (225 °C). Thus, CaO was considered to be the best catalyst among the others. This tri-phase reaction require continuous fast mixing and the yield depends on the reaction parameters like catalyst amount, temperature, reaction time and molar ratio (methanol: oil). The reusability of these heterogeneous catalysts simplified the purification step, reduced the waste generation and make the final product technically and economically viable.  相似文献   
30.

This study has been focused on the efficient removal of Pb (II) from contaminated waters by biosorption using plant derived material. Accordingly an indigenous shrub, Tinospora cordifolia has been identified as the most suitable biosorbent. The plant biomass was subjected to optimization of various parameters such as the pH, equilibrium time, dosage, concentration, temperature and the applicable adsorption models. The optimum pH identified was 4.0 with a contact time of 60 min at room temperature (27 ± 2 °C). The experimental data fitted well to adsorption isotherms and the uptake capacity of Pb (II) was found to be 20.83 and 63.77 mg/g in batch mode and column mode, respectively. The high correlation factors obtained for Langmuir and Freundlich models indicated that both models were obeyed by the system. Kinetic study for adsorption of Pb (II) follow only pseudo second order rate of reaction. The accumulation of lead in biomass was confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The FTIR analysis indicated the involvement of hydroxyl (−OH), alkenes (=CH) and carbonyl group (C = O) chelates in metal binding. The SEM and EDX analysis showed the structural changes and the filling of voids in the biomass thus, it indicated the metal-binding mechanism. In elution studies, the 0.1 M Na2CO3 was found to be the best with about 71% elution of the adsorbed metal. The biomass was then used for the removal of Pb (II) in synthetic and real wastewater samples from a lead-acid battery industry. It is also noteworthy that even at a very high concentration of 450 mg/L, the biomass was showing about 92% removal. The result is to establish the efficacy of T. cordifolia as a very good bioadsorbent for the Pb (II) removal from contaminated water.

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