890 resultados para waste component
Resumo:
Latex waste like glove waste was effectively modified using a new reclaiming agent, thiocarbanilide. This modified waste was blended with linear low-density polyethylene (LLDPE) to develop a novel thermoplastic elastomer. Both uncrosslinked and dynamically crosslinked blends were prepared and their properties were studied. The results were found to be comparable to those of conventional thermoplastic elastomers.
Science and technology of rubber reclamation with special attention to NR-based waste latex products
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A comprehensive overview of reclamation of cured rubber with special emphasis on latex reclamation is depicted in this paper. The latex industry has expanded over the years to meet the world demands for gloves, condoms, latex thread, etc. Due to the strict specifications for the products and the unstable nature of the latex as high as 15% of the final latex products are rejected. As waste latex rubber (WLR) represents a source of high-quality rubber hydrocarbon, it is a potential candidate for generating reclaimed rubber of superior quality. The role of the different components in the reclamation recipe is explained and the reaction mechanism and chemistry during reclamation are discussed in detail. Different types of reclaiming processes are described with special reference to processes, which selectively cleave the cross links in the vulcanized rubber. The state-of-the-art techniques of reclamation with special attention on latex treatment are reviewed. An overview of the latest development concerning the fundamental studies in the field of rubber recycling by means of low-molecular weight compounds is described. A mathematical model description of main-chain and crosslink scission during devulcanization of a rubber vulcanizate is also given.
Resumo:
Waste latex products are converted to a processabto material by a novel economical process developed in our laboratory , It contains rubber hydrocarbon of very high quality and Is lightly cross -linked. Styrene-butadlene rubber is mixed with latex reclaim In different proportions . The mechanical properties are found to be improved up to 60 percent replacement of styrene-butadlene rubber by latex reclaim . The curing of styrene-butadiene rubber Is found to be accelerated by the addition of latex reclaim. The processablllty study shows that the blends can be processed similar to SBRINR blends.
Resumo:
Latex waste products contain rubber hydrocarbon of very high quality, which is only lightly cross linked. Selected wastes such as thread waste and glove waste were modified into processable materials by a novel economic process and thermoplastic elastomers were prepared by blending these modified waste materials with high density polyethylene in various proportions. The mechanical properties as well as the rheological behaviour of these blends were evaluated and compared with those of the natural rubber-high density polyethylene blends.
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This manuscript describes the first example of silver ion complex of a dendritic tetranitrile ligand catalyzed one-pot three component Mannich reaction and 1,5-benzodiazepine synthesis. The catalyst can be separated from the products by a change in the solvent. The catalyst is reusable.
Resumo:
Plasticized poly(vinyl chloride) (pPVC), although a major player in the medical field, is at present facing lot of criticism due to some of its limitations like the leaching out of the toxic plasticizer, di ethylhexyl phthalate (DEHP) to the medium and the emission of an environmental pollutant,dioxin gas,at the time of the post use disposal of PVC Products by incineration. Due to these reasons, efforts are on to reduce the use of pPVC considerably in the medical field and to find viable alternative materials. The present study has been undertaken in this context to find a suitable material for the manufacture of medical aids in place of pPVC. The main focus of this study has been to find out a non-DEHP material as plasticizer for pPVC and another suitable material for the complete repalcement of pPVC for blood/ blood component storage applications.Two approaches have been undertaken for this purpose-(1)the controversial plasticizer, DEHP has been partially replaced by polymeric plasticizers(2) an alternative material, namely, metallocene polyolefin (mPO) has been used and suitably modified to match the properties of flexible PVC used for blood and blood component storage applications.
Resumo:
The laser produced plasma from the multi-component target YBa2CU3O7 was analyzed using Michelson interferometry and time resolved emission spectroscopy. The interaction of 10 ns pulses of 1.06 mum radiation from a Q-switched Nd:YAG laser at laser power densities ranging from 0.55 GW cm-2 to 1.5 GW cm-2 has been studied. Time resolved spectral measurements of the plasma evolution show distinct features at different points in its temporal history. For a time duration of less than 55 ns after the laser pulse (for a typical laser power density of 0.8 GW cm-2, the emission spectrum is dominated by black-body radiation. During cooling after 55 ns the spectral emission consists mainly of neutral and ionic species. Line averaged electron densities were deduced from interferometric line intensity measurements at various laser power densities. Plasma electron densities are of the order of 1017 cm-3 and the plasma temperature at the core region is about 1 eV. The measurement of plasma emission line intensities of various ions inside the plasma gave evidence of multiphoton ionization of the elements constituting the target at low laser power densities. At higher laser power densities the ionization mechanism is collision dominated. For elements such as nitrogen present outside the target, ionization is due to collisions only.
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This thesis presents a detailed account of a cost - effective approach towards enhanced production of alkaline protease at profitable levels using different fermentation designs employing cheap agro-industrial residues. It involves the optimisation of process parameters for the production of a thermostable alkaline protease by Vibrio sp. V26 under solid state, submerged and biphasic fermentations, production of the enzyme using cell immobilisation technology and the application of the crude enzyme on the deproteinisation of crustacean waste.The present investigation suggests an economic move towards Improved production of alkaline protease at gainful altitudes employing different fermentation designs utilising inexpensive agro-industrial residues. Moreover, the use of agro-industrial and other solid waste substrates for fermentation helps to provide a substitute in conserving the already dwindling global energy resources. Another alternative for accomplishing economically feasible production is by the use of immobilisation technique. This method avoids the wasteful expense of continually growing microorganisms. The high protease producing potential of the organism under study ascertains their exploitation in the utilisation and management of wastes. However, strain improvement studies for the production of high yielding variants using mutagens or by gene transfer are required before recommending them to Industries.Industries, all over the world, have made several attempts to exploit the microbial diversity of this planet. For sustainable development, it is essential to discover, develop and defend this natural prosperity. The Industrial development of any country is critically dependent on the intellectual and financial investment in this area. The need of the hour is to harness the beneficial uses of microbes for maximum utilisation of natural resources and technological yields. Owing to the multitude of applications in a variety of industrial sectors, there has always been an increasing demand for novel producers and resources of alkaline proteases as well as for innovative methods of production at a commercial altitude. This investigation forms a humble endeavour towards this perspective and bequeaths hope and inspiration for inventions to follow.
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The present study aimed at the utlisation of microbial organisms for the
production of good quality chitin and chitosan. The three strains used for the
study were Lactobacillus plantarum, Lactobacililus brevis and Bacillus subtilis.
These strains were selected on the basis of their acid producing ability to reduce
the pH of the fermenting substrates to prevent spoilage and thus caused
demineralisation of the shell. Besides, the proteolytic enzymes in these strains
acted on proteinaceous covering of shrimp and thus caused deprotenisation of
shrimp shell waste. Thus the two processes involved in chitin production can be
affected to certain extent using bacterial fermentation of shrimp shell.Optimization parameters like fermentation period, quantity of inoculum,
type of sugar, concentration of sugar etc. for fermentation with three different
strains were studied. For these, parameters like pH, Total titrable acidity (TTA),
changes in sugar concentration, changes in microbial count, sensory changes
etc. were studied.Fermentation study with Lactobacillus plantarum was continued with 20%
w/v jaggery broth for 15 days. The inoculum prepared yislded a cell
concentration of approximately 108 CFU/ml. In the present study, lactic acid and
dilute hydrochloric acid were used for initial pH adjustment because; without
adjusting the initial pH, it took more than 5 hours for the lactic acid bacteria to
convert glucose to lactic acid and during this delay spoilage occurred due to
putrefying enzymes active at neutral or higher pH. During the fermentation study,
pH first decreased in correspondence with increase in TTA values. This showed
a clear indication of acid production by the strain. This trend continued till their
proteolytic activity showed an increasing trend. When the available sugar source
started depleting, proteolytic activity also decreased and pH increased. This was
clearly reflected in the sensory evaluation results. Lactic acid treated samples
showed greater extent of demineralization and deprotenisation at the end of
fermentation study than hydrochloric acid treated samples. It can be due to the
effect of strong hydrochloric acid on the initial microbial count, which directly
affects the fermentation process. At the end of fermentation, about 76.5% of ash was removed in lactic acid treated samples and 71.8% in hydrochloric acid
treated samples; 72.8% of proteins in lactic acid treated samples and 70.6% in
hydrochloric acid treated samples.The residual protein and ash in the fermented residue were reduced to
permissible limit by treatment with 0.8N HCI and 1M NaOH. Characteristics of
chitin like chitin content, ash content, protein content, % of N- acetylation etc.
were studied. Quality characteristics like viscosity, degree of deacetylation and
molecular weight of chitosan prepared were also compared. The chitosan
samples prepared from lactic acid treated showed high viscosity than HCI treated
samples. But degree of deacetylation is more in HCI treated samples than lactic
acid treated ones. Characteristics of protein liquor obtained like its biogenic
composition, amino acid composition, total volatile base nitrogen, alpha amino
nitrogen etc. also were studied to find out its suitability as animal feed
supplement.Optimization of fermentation parameters for Lactobacillus brevis
fermentation study was also conducted and parameters were standardized. Then
detailed fermentation study was done in 20%wlv jaggery broth for 17 days. Also
the effect of two different acid treatments (mild HCI and lactic acid) used for initial
pH adjustment on chitin production were also studied. In this study also trend of
changes in pH. changes in sugar concentration ,microbial count changes were
similar to Lactobacillus plantarum studies. At the end of fermentation, residual
protein in the samples were only 32.48% in HCI treated samples and 31.85% in
lactic acid treated samples. The residual ash content was about 33.68% in HCI
treated ones and 32.52% in lactic acid treated ones. The fermented residue was
converted to chitin with good characteristics by treatment with 1.2MNaOH and
1NHCI.Characteristics of chitin samples prepared were studied and extent of Nacetylation
was about 84% in HCI treated chitin and 85%in lactic acid treated
ones assessed from FTIR spectrum. Chitosan was prepared from these samples
by usual chemical method and its extent of solubility, degree of deacetylation,
viscosity and molecular weight etc were studied. The values of viscosity and
molecular weight of the samples prepared were comparatively less than the
chitosan prepared by Lactobacillus plantarum fermentation. Characteristics of protein liquor obtained were analyzed to determine its quality and is suitability as
animal feed supplement.Another strain used for the study was Bacillus subtilis and fermentation
was carried out in 20%w/v jaggery broth for 15 days. It was found that Bacillus
subtilis was more efficient than other Lactobacillus species for deprotenisation
and demineralization. This was mainly due to the difference in the proteolytic
nature of the strains. About 84% of protein and 72% of ash were removed at the
end of fermentation. Considering the statistical significance (P
Resumo:
This thesis analyzed waste generation and waster disposal problems in municipalities and Cochin Corporation in Ernakulam district.Then the potential of resource recovery and recycling from biodegradable and non bio-degradable waste is established.The study further focused on the need for segregation of waste at the source as biodegradable and non biodegradable solid waste.The potential of resource recovery is explained in detail through the case study.The thesis also highlights the economically viable and environmental friendly methods o f treatment of waste.But the problem is that concerted and earnest attempts are lacking in making use of such methods.In spite of the health problems faced,people living near the dump sites are forced to stay there either because of their weak economic background or family ties.The study did not calculate the economic cost of health problems arising out of unscientific and irresponsible methods of waste disposal.
Resumo:
Biodegradation is the chemical degradation of materials brought about by the action of naturally occurring microorganisms. Biodegradation is a relatively rapid process under suitable conditions of moisture, temperature and oxygen availability. The logic behind blending biopolymers such as starch with inert polymers like polyethylene is that if the biopolymer component is present in sufficient amount, and if it is removed by microorganisms in the waste disposal environment, then the base inert plastic should slowly degrade and disappear. The present work focuses on the preparation of biodegradable and photodegradable blends based on low density polyethylene incorporating small quantities of ionomers as compatibilizers. The thesis consists of eight chapters. The first chapter presents an introduction to the present research work and literature survey. The details of the materials used and the experimental procedures undertaken for the study are described in the second chapter. Preparation and characterization of low density polyethylene (LDPE)-biopolymer (starch/dextrin) blends are described in the third chapter. The result of investigations on the effect of polyethylene-co-methacrylic acid ionomers on the compatibility of LDPE and starch are reported in chapter 4. Chapter 5 has been divided into two parts. The first part deals with the effect of metal oxides on the photodegradation of LDPE. The second part describes the function of metal stearates on the photodegradation of LDPE. The results of the investigations on the role of various metal oxides as pro-oxidants on the degradation of ionomer compatibilized LDPE-starch blends are reported in chapter 6. Chapter 7 deals with the results of investigations on the role of various metal stearates as pro-oxidants on the degradation of ionomer compatibilized LDPE-starch blends. The conclusion of the investigations is presented in the last chapter of the thesis.
Resumo:
Heavy metals are major toxic pollutants with severe health effects on humans. They are released into the environment from a variety of industrial activities. Cadmium, lead, zinc, chromium and copper are the most toxic metals of widespread use in industries such as tanning, electroplating, electronic equipment manufacturing and chemical processing plants. Heavy metals contribute to a variety of adverse health environmental effects due to their acute and chronic exposure through air, water and food chain. Conventional treatment methods of metal removal are often limited by their cost and ineffectiveness at low concentrations. Adsorption, the use of inactivated biomass as adsorbents offers an attractive potential alternative to their conventional methods. Mango peel and Alisma plantago aquatica are naturally occurring and abundant biomass can offer an economical solution for metal removal.The Cd(II), Pb(II), Zn(II), Cr(III) and Cu(II) adsorption by milled adsorbents of mango peel and Alisma plantago aquatica were evaluated in batches.
Resumo:
Prawn shell waste collected from shrimp-processing plants in Cochin, India, was subjected to fermentation using 20 chitinoclastic and proteolytic/non-proteolytic bacterial strains. The products generated were analysed for protein, lipid, total sugars, N-acetyl glucosamine, free amino acids and ash. Shrimp diets were prepared using these 20 fermented products and a control diet using raw prawn shell waste. Feeding experiment was conducted with postlarvae (PL21) of Indian white prawn, Fenneropenaeus indicus for a period of 21 days. Biogrowth parameters such as mean weight gain, feed conversion ratio, specific growth rate and protein efficiency ratio were estimated and the animals were challenged with white spot virus orally via diet. Enhanced growth could be observed in prawns fed F134 and F124, incorporated with the fermentation products generated using Bacillus spp., C134 and C124 respectively. The percentage survival of prawns after 7 days of challenge was found to be highest for groups fed diet F111 incorporated with fermentation product generated using Bacillus sp. These products of bacterial fermentation hold promise as growth enhancers and immunostimulants in aquaculture. KEY WORDS: biogrowth parameters, feed
Resumo:
Multi-component reactions are effective in building complex molecules in a single step in a minimum amount of time and with facile isolation procedures; they have high economy1–7 and thus have become a powerful synthetic strategy in recent years.8–10 The multicomponent protocols are even more attractive when carried out in aqueous medium. Water offers several benefits, including control over exothermicity, and the isolation of products can be carried out by single phase separation technique. Pyranopyrazoles are a biologically important class of heterocyclic compounds and in particular dihydropyrano[2,3-c]pyrazoles play an essential role in promoting biological activity and represent an interesting template in medicinal chemistry. Heterocyclic compounds bearing the 4-H pyran unit have received much attention in recent years as they constitute important precursors for promising drugs.11–13 Pyrano[2,3-c]pyrazoles exhibit analgesic,14 anti-cancer,15 anti-microbial and anti-inflammatory16 activity. Furthermore dihydropyrano[2,3-c]pyrazoles show molluscidal activity17,18 and are used in a screening kit for Chk 1 kinase inhibitor activity.19,20 They also find applications as pharmaceutical ingredients and bio-degradable agrochemicals.21–29 Junek and Aigner30 first reported the synthesis of pyrano[2,3-c]pyrazole derivatives from 3-methyl-1-phenylpyrazolin-5-one and tetracyanoethylene in the presence of triethylamine. Subsequently, a number of synthetic approaches such as the use of triethylamine,31 piperazine,32 piperidine,33 N-methylmorpholine in ethanol,34 microwave irradiation,35,36 solvent-free conditions,37–39 cyclodextrins (CDs),40 different bases in water,41 γ -alumina,42 and l-proline43 have been reported for the synthesis of 6-amino-4-alkyl/aryl-3-methyl- 2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles. Recently, tetraethylammonium bromide (TEABr) has emerged as mild, water-tolerant, eco-friendly and inexpensive catalyst. To the best of our knowledge, quaternary ammonium salts, more specifically TEABr, have notbeen used as catalysts for the synthesis of pyrano[2,3-c]pyrazoles, and we decided to investigate the application of TEABr as a catalyst for the synthesis of a series of pyrazole-fused pyran derivatives via multi-component reactions
Resumo:
A spectral angle based feature extraction method, Spectral Clustering Independent Component Analysis (SC-ICA), is proposed in this work to improve the brain tissue classification from Magnetic Resonance Images (MRI). SC-ICA provides equal priority to global and local features; thereby it tries to resolve the inefficiency of conventional approaches in abnormal tissue extraction. First, input multispectral MRI is divided into different clusters by a spectral distance based clustering. Then, Independent Component Analysis (ICA) is applied on the clustered data, in conjunction with Support Vector Machines (SVM) for brain tissue analysis. Normal and abnormal datasets, consisting of real and synthetic T1-weighted, T2-weighted and proton density/fluid-attenuated inversion recovery images, were used to evaluate the performance of the new method. Comparative analysis with ICA based SVM and other conventional classifiers established the stability and efficiency of SC-ICA based classification, especially in reproduction of small abnormalities. Clinical abnormal case analysis demonstrated it through the highest Tanimoto Index/accuracy values, 0.75/98.8%, observed against ICA based SVM results, 0.17/96.1%, for reproduced lesions. Experimental results recommend the proposed method as a promising approach in clinical and pathological studies of brain diseases