Integrated framework to optimize RAM and cost decisions in a process plant

The research implications of reliability, availability and maintainability (RAM) aspects of engineering systems in recent years have increased substantially due to rising operation and maintenance costs. To strike a balance between the two the paper presents a framework which makes use of both qualitative and quantitative techniques to optimize RAM and cost decisions in a process plant. In the quantitative analysis, the imprecise and vague information regarding the system failure behavior is quantified by using the principles of fuzzy mathematics in terms of fuzzy and crisp values. Further, to manage the system reliability for best economic performance a resource optimization model based on multi-stage decision making (MSDM) has been proposed. The model makes use of crisp output values of unit's reliability along with relevant system information (number of components, manpower, cost ranges). In the qualitative analysis the in-depth analysis of the system is carried out using Root Cause analysis (RCA) and Failure Mode & Effects Analysis (FMEA). The ambiguities associated with the traditional FMEA are handled using Fuzzy Decision Making System (FDMS) and Grey Relation Analysis (GRA). The suggested framework has been illustrated with the help of a case.     

Organochlorine pesticide residues in fodder from rural areas of Haryana,India

Residues of organochlorine pesticides (OCPs) namely 1,2,3,4,5,6-hexachlorocyclohexane isomers (HCH-isomers), 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) and its metabolites, and endosulfan stereoisomers were analyzed in dry and green fodder samples from rural areas of Ambala, Gurgaon, and Hisar districts of Haryana, India during winter, summer, and post-monsoon seasons. The HCH isomers γ-HCH and β-HCH, and DDT and its metabolites p,p′-DDD, p,p′-DDE, and p,p′-DDT had more traceability in test samples as compared to other isomers and metabolites studied. Total OCPs (ΣOCPs), i.e., ΣHCH, ΣDDT, and Σendosulfan were found to be the highest in wheat straw (1.1–1.2?mg?kg^?1) from Ambala and Gurgaon, followed by that in sorghum straw (0.46?mg?kg^?1) from Hisar. Dry fodder samples were found to have relatively higher residue levels than green fodders. In case of green fodder samples, maximum ΣOCP residues of 0.44?mg?kg^?1 were found in whole plant samples of sorghum from Gurgaon district followed by that in pearl millet (0.40?mg?kg^?1) from Ambala. The findings indicate highly significant differences (p?>?0.0001) in ΣOCPs and ΣDDT in wheat straw between different districts and reveal the persistence of OCP residues in both dry and green fodder samples in the study area.     

Antioxidant rich diet supplements (Spirulina and tamarind fruit pulp) mitigate hematological disorders in fluoride exposed mice

The effect of antioxidant rich diet supplements of Spirulina and tamarind fruit pulp at 230 mg kg^?1 body weight, separately as well as in combination, on various hematological parameters of Swiss albino mice exposed to fluoride for seven days at daily doses of 190 mg kg^?1 body weight and for 90 days at daily doses of 94 mg kg^?1 body weight is reported. Compared with controls, fluoride exposure decreased erythrocyte (12%–18%), leukocyte (16%) and platelet counts (7%, only for short-term exposure), hemoglobin (2%–17%) and packed cell volume (2%–14%) in Swiss albino mice reared on standard feed but these were altered little in the diet supplement groups. Fluoride exposure decreased lymphocytes in both standard feed (16%–21%) and diet supplement groups (5%–19%, but only after long-term exposure). Fluoride withdrawal led to recovery of the post-treated mice from long-term exposure. Spirulina alone and also in combination with tamarind fruit pulp was found more effective than tamarind alone in reducing hematological disorders in fluoride treated mice.     

Sorption and leaching behavior of hexaconazole as influenced bysoilproperties

Sorption and leaching behavior of hexaconazole in four different soils (alluvial, red, laterite, and black) was studied using a batch equilibration technique. The values of the Freundlich adsorption constant 1/n_ads ranged from 0.75 to 0.85 for all four soils, showing strong non-linear behavior. Upon stepwise desorption with CaCl₂ solution (10 mmol·L^?1), release of hexaconazole was maximum with the first elution, the amount decreasing with each subsequent one. The leaching behavior under saturated flow conditions was also studied with soil columns packed in polythene tubes. The mobility of hexaconazole was maximum in sandy loam and minimum in black soil.     

Effects of UV-B radiation on the gills of Catla catla during early development

Scanning electron microscopic (SEM) study of gills of Catla catla catla (17-day-old) exposed to UV-B radiation (145?µW?cm^?2 at the water surface) for three different exposure times: 5, 10 and 15?min was conducted. Fish without UV-B exposure served as control. UV-B radiation damaged both gill filaments and lamellae. The intensity of damage was minimal in 5?min exposed fish, followed by 10?min exposed fish and maximal in 15?min. The gill epithelium was severely damaged in 15?min irradiated fish compared to control. Pavement cells (PVCs) were damaged and the numbers of microridges within PVCs decreased. The deep boundary of PVC was not clear. In some area of gill epithelium, PVCs were destroyed and mitochondrion-rich cells (MRCs) were exposed. The 5?min exposure reduced the number of microridges in the PVCs, but the boundary of PVCs was still visible. MRCs in the gill epithelium were not exposed in 5?min exposed fish. The damage to PVCs and subsequent exposure of MRCs in UV-B irradiated fish may hamper respiratory functions and disturb osmoregulation in catla.     

Acute toxicity of ammonia to a freshwater teleost,Labeo bata larvae

Ammonia toxicity tests were performed with Labeo bata (bata) larvae of three different size groups. One hundred percent survival of larvae (500.0?±?4.0?mg) was recorded when exposed to ammonia concentrations of 1.0–13.56?mg?L^?1 at 96?h of exposure. Bata larvae exposed to ammonia concentrations of 15.8–25?mg?L^?1 showed 10–74% mortalities. The 96?h LC₅₀ value for 200 (±5), 250 (±2) and 500 (±4) mg bata larvae were 11.5, 16.8 and 22.5?mg?L^?1 un-ionised ammonia concentrations, respectively. When fish were exposed to different doses of ammonia, behavioural changes immediately occurred even at the lowest dose. At first, the fish became hyperexcitable, the skin darkened and they showed an increased ventilation frequency, fish behaviour became normal, 24?h after exposure. A 96?h LC₅₀ value of un-ionised ammonia showed direct relationship with the increasing size of bata larvae.     

Monitoring toxicity of an azo dye methyl red and a heavy metal Cu,using plant and animal bioassays

Toxicities of an azo dye methyl red and a heavy metal copper (Cu) were quantified, using growth and mortality as end points, in four plant species and three animal species by subjecting them to short-term (4 days for animals, 10 days for plants) static bioassays. Lemna aequinoctialis Welwitch (EC₅₀: 7–16 ppm) was found to be the most sensitive species for methyl red, Ceratophyllum demersum L. (EC₅₀: 25 ppm) and Lactuca sativa L. (EC₅₀: 56 ppm) were intermediate, while Oryza sativa L. shows reduction in seedling vigor (9–27%) of <50%, being the least sensitive amongst the tested plant species. Methyl red toxicity is almost 3–5-fold higher in growing medium (pH = 5.8–6.0), even at high nutrient levels, while Cu toxicity is higher in nutrient-poor alkaline medium at alkaline pH (8.3–8.7; EC₅₀: Ceratophyllum = 104–200 ppb; Lemna = 100–170 ppb) compared to nutrient-rich acidic medium (pH = 5.4–5.7; EC₅₀: Ceratophyllum = 2600–3175 ppb; Lemna = 4350–4715 ppb). Rice tolerance (EC₅₀: 6500 ppb) was found to be higher than hydrophytes while lettuce was most tolerant to Cu. Fish sensitivity toward the test chemicals was almost parallel to Ceratophyllum and Lemna [Gambusia affinis Baird and Gerard (LC₅₀: 250 ppb for Cu) and Poecilia reticulata Peters (LC₅₀: 24 ppm for methyl red)]. Similar to the plants, dye toxicity increased markedly (LC₅₀: 7 ppm) in the acidic medium (pH = 6.0). Amongst the tested organisms, Daphnia was found to be most sensitive to methyl red (EC₅₀: 6 ppm) while its sensitivity to Cu (EC₅₀: 230 ppb) was similar to hydrophytes and fish. Initially, the combination of dye and Cu (at their sublethal concentrations) had additive effects in duckweed, while dye concentration ruled afterward. These results indicate that hydrophytes and animals are equally sensitive toward the test chemicals. Dye toxicity in hydrophytes and fish was pH dependent, while in the case of Cu, it is related to the nutrient status of the growth medium of plants.     

Development and validation of a spectrophotometric method for soil adsorption study of malathion on three Indian soils

In view of the widespread use of pesticides in agriculture and its associated toxic effects on environment and human beings, the fate of these chemicals in soil is of major concern. The pesticide adsorption process is one of the major factors affecting its persistence and movement in the soil. With a view of studying the fate of malathion in soil, the adsorption of this insecticide was studied on three Indian soils by using batch equilibrium method. To carry out the adsorption study, a new simple, sensitive, and rapid method was developed, based on microwave-assisted alkaline hydrolysis of insecticide to the dimethyl dithiophosphate and its subsequent reaction with copper(I) perchlorate in acetonitrile. On mixing the reagents, a yellow color developed, which was stable for 120?min and was measured at 419?nm. The adsorption of malathion was studied by using Freundlich's adsorption equation and n _f values were observed less than 1 in all the soils. The leaching behavior of the insecticide was studied in terms of ground ubiquity score, which was below 1.8, classifying malathion as non-leacher pesticide, and hence it is not hazardous.     

Applications of natural polysaccharide-based beads for slow release herbicide formulation

This work deals with the use of polysaccharide-based beads for controlled release of the herbicide atrazine. This article discusses the release of the herbicide atrazine from neem-alginate-clay-based beads. Formulation characteristics such as entrapment efficiency, bead size, and diffusion mechanism for release of atrazine have been evaluated.     

Synthesis and characterization of an ion exchanger based on tamarind kernel powder and its application for removal of some metal ions from industrial effluents

A resin synthesized from tamarind kernel powder possesses high selectivity for metal ions. Distribution coefficients for some metal ions has been determined by the batch method. The influence of pH on ion exchange capacity and K _d value of metal ions were studied. The resin has been characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, chemical composition and ion exchange capacity (IEC). The selectivity order is Pb²⁺?>?Cu²⁺?>?Fe²⁺?>?Zn²⁺?>?Ni²⁺. Removal of metal ions from the aqueous solution and from effluents of a steel mill has been studied.