992 resultados para Coal Tar
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v.I. Introduction. Alcohols, neutral alcoholic derivatives, sugars, starch and its isomers, vegetable acids, etc. 2d ed., rev. & enl.--v.II. Fixed oils, fats, waxes, glycerol, nitroglycerin and nitroglycerin explosives. Hydrocarbons, petroleum and coal-tar products, asphalt, phenols and creosotes. 2d ed., rev. & enl.--v. III, pt.I. Acid derivatives of phenols, aromatic acids, resins, and essential oils. Tannins, dyes, and colouring matters, writing inks. 2d ed., rev. & enl.--v. III, pt.II. Amines and ammonium bases, hydrarzines, bases from tar, vegetable alkaloids. 2d ed., rev. and enl. [1892] --v.III, pt.III. Vegetable alkaloids (concluded), non-basic vegetable bitter principles, animal bases, animal acids, cyanogen and its derivatives. 2d ed., rev. & enl. [1896]--v.IV. Proteids and albuminous principles, proteoïds or albuminoïds. 2d ed., rev. & enl. 1898.
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"References" at end of each chapter.
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From October 2014 to March 2015, I provided excavation oversight services at a property with substantial environmental concerns. The property in question is located near downtown Seattle and was formerly occupied by the Washington’s first coal gasification plant. The plant operated from 1888 to 1908 and produced coal gas for municipal use. A coal tar like substance with a characteristically high benzene concentration was a byproduct of the coal gasification process and heavily contaminated at or below the surface grade of the plant as shown in previous investigations on the property. Once the plant ceased operation in 1908 the property was left vacant until 1955 when the site was filled in and a service station was built on the property. The main goal of the excavation was not to achieve cleanup on the property, but to properly remove what contaminated soil was encountered during the redevelopment excavation. Areas of concern were identified prior to the commencement of the excavation and an estimation of the extent of contamination on the property was developed. “Hot spots” of contaminated soil associated with the fill placed after 1955 were identified as areas of concern. However, the primary contaminant plume below the property was likely sourced from the coal gasification plant, which operated at an approximate elevation of 20 feet. We planned to constrain the extents of the soil contamination below the property as the redevelopment excavation progressed. As the redevelopment excavation was advanced down to an elevation of approximately 20 feet, soil samples were collected to bound the extents of contamination in the upper portion of the site. The hot spots, known pockets of carcinogenic polycyclic aromatic hydrocarbons (cPAH) located above 20 feet elevation, were excavated as part of the redevelopment excavation. Once a hot spot was excavated, soil samples were collected from the north, south, east, west and bottom sidewalls of the hot spot excavation to check for remaining cPAH. Additionally, four underground storage tanks (USTs) associated with the service station were discovered and subsequently removed. Soil samples were also collected from the resulting UST excavation sidewalls to check for remaining petroleum hydrocarbons. Once the excavation reached its final excavation depth of 20 to 16 feet in elevation, bottom of excavation samples were collected on a 35 foot by 35 foot grid to test for concentrations of contaminants remaining onsite. Once the redevelopment excavation was complete, soils observed from borings drilled for either structural elements, geotechnical wells, or environmental wells were checked for any evidence of contamination using field screening techniques. Evidence of contamination was used to identify areas below the final excavation grade which had been impacted by the operation of the coal gasification plant. Samples collected from the excavation extents of hot spots and USTs show that it was unlikely that any contamination traveled from the post-1955 grade down to the pre-1955 grade. Additionally, the lack of benzene in the bottom of excavation samples suggests that a release from the coal gasification plant occurred below the redevelopment excavation final elevations of 20 to 16 feet. Qualitative data collected from borings for shoring elements and wells indicated that the spatial extent of the subsurface contaminant plume was different than initially estimated. Observations of spoils show that soil contamination extends further to the southwest and not as far to the east and north than originally estimated. Redefining the extent of the soil contamination beneath the property will allow further subsurface investigations to focus on collecting quantitative data in areas that still represent data gaps on the property, and passing over areas that have shown little signs of contamination. This information will help with the formation of a remediation plan should the need to clean up the site arise in the future.
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In the 1960s the benefits of government regulation of technology were believed to outweigh any costs. But recent studies have claimed that regulation has negative effects on innovation, health and consumer choice. This case study on food colours examines such claims. EFFECTS ON HEALTH were measured by allocating a hazard rating to each colour. The negative list of 1925 removed three harmful colours which were rapidly replaced, so the benefits were short-lived. Had a proposed ban been adopted in the 1860s it would have prevented many years exposure to hazardous mineral colours. The positive list of 1957 reduced the proportion of harmful coal tar dyes from 54% of the total to 20%. Regulations brought a greater reduction in hazard levels than voluntary trade action. Delays in the introduction of a positive list created a significant hazard burden. EFFECTS ON INNOVATION were assessed from patents and discovery dates. Until the 1950s food colours were adopted from textile colours. The major period of innovation for coal tar colours was between 1856 and 1910, finishing well before regulations were made in 1957, so regulations cannot be blamed for the decline. Regulations appear to have spurred the development of at least one new coal tar dye, and many new plant colours, creating a new sector of the dye industry. EFFECTS ON CONSUMER CHOICE were assessed by case studies. Coloured milk, for example, was banned despite its popularity. Regulations have restricted choice, but have removed from the market foods that were nutritionally impoverished and poor value for money. Compositional regulations provided health protection because they reduced total exposure to colours from certain staple foods. Restricting colours to a smaller range of foods would be an effective way of coping with problems of quality and imperfect toxicological knowledge today.
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Healthcare providers and policy makers are faced with an ever-increasing number of medical publications. Searching for relevant information and keeping up to date with new research findings remains a constant challenge. It has been widely acknowledged that narrative reviews of the literature are susceptible to several types of bias and a systematic approach may protect against these biases. The aim of this thesis was to apply quantitative methods in the assessment of outcomes of topical therapies for psoriasis. In particular, to systematically examine the comparative efficacy, tolerability and cost-effectiveness of topical calcipotriol in the treatment of mild-to-moderate psoriasis. Over the years, a wide range of techniques have been used to evaluate the severity of psoriasis and the outcomes from treatment. This lack of standardisation complicates the direct comparison of results and ultimately the pooling of outcomes from different clinical trials. There is a clear requirement for more comprehensive tools for measuring drug efficacy and disease severity in psoriasis. Ideally, the outcome measures need to be simple, relevant, practical, and widely applicable, and the instruments should be reliable, valid and responsive. The results of the meta-analysis reported herein show that calcipotriol is an effective antipsoriatic agent. In the short-tenn, the pooled data found calcipotriol to be more effective than calcitriol, tacalcitol, coal tar and short-contact dithranol. Only potent corticosteroids appeared to have comparable efficacy, with less short-term side-effects. Potent corticosteroids also added to the antipsoriatic effect of calcipotriol, and appeared to suppress the occurrence of calcipotriol-induced irritation. There was insufficient evidence to support any large effects in favour of improvements in efficacy when calcipotriol is used in combination with systemic therapies in patients with severe psoriasis. However, there was a total absence of long-term morbidity data on the effectiveness of any of the interventions studied. Decision analysis showed that, from the perspective of the NHS as payer, the relatively small differences in efficacy between calcipotriol and short-contact dithranol lead to large differences in the direct cost of treating patients with mildto-moderate plaque psoriasis. Further research is needed to examine the clinical and economic issues affecting patients under treatment for psoriasis in the UK. In particular, the maintenance value and cost/benefit ratio for the various treatment strategies, and the assessment of patient's preferences has not yet been adequately addressed for this chronic recurring disease.
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Atopic dermatitis is a very common inflammatory skin disease, particularly in children. A systematic review of randomised controlled trials of treatments for atopic dermatitis (AD) was carried out to assess how many trials exist, what they cover, what they do not cover, the research gaps, provide a 'blue print' for future Cochrane Reviews and assist those making treatment recommendations by summarising the available RCT evidence, using descriptive statistics. The Cochrane Collaboration systematic review process formed the basis of the methodology, from which over 4000 studies were located via electronic database searches and hand searching of journals. A total of 292 trials were finally included covering 9 treatment groups and over 48 individual treatments. There are lots of trials covering lots of interventions but gaps are evident. However, there is evidence of a benefit in the treatment of atopic dermatitis with topical corticosteroids, psychological approaches, UV light, ascomycin derivatives, topical tacrolimus and oral cyclosporin. Treatments that show limited evidence of a benefit include non-sedatory antihistamines, topical doxepin, the oral antibiotic Cefadroxil on clinically infected AD, the topical antibacterial Mupirocin on clinically uninfected AD, Chinese herbs, hypnotherapy and biofeedback, massage therapy, dietary manipulation, house dust mite reduction, patient education, emollients, allergen antibody complexes of house dust mite and thymic extracts. Treatments that show no evidence of benefit include sedatory antihistamines, oral sodium cromoglycate, oral antibiotics on clinically uninfected AD, topical antibacterials, topical antifungals, aromatherapy essential oils, borage oil, fish oil, evening primrose oil, enzyme-free clothes detergent, cotton clothing, house dust mite hyposensitisation, salt baths, topical coal tar, topical cyclosporin and platelet-activating-factor antagonist. When interpreting the conclusions of this thesis it is important to understand that lack of evidence does not equal lack of efficacy, particularly considering the interventions that are commonly in use today to treat atopic dermatitis that have not been subjected to RCTs, such as occlusive dressings, water softening devices and stress management among many others.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Manvers coal has been pyrolysed to 500ºC in a stirred autoclave under various pressures of nitrogen (pyrolysis) and hydrogen (hydropyrolysis). All products were investigated. Pyrolysis of coals involves the transfer of hydrogen atoms from one part of their structure to another. In the above experiments there was no way of labelling the hydrogen or of distinguishing between hydrogen which was initially part of the coal and hydrogen originating in the external atmosphere. Consequently, Manvers coal has been pyrolysed in an atmosphere of deuterium in order to obtain greater insight into the mechanism of hydropyrolysis. In particular it was hoped to distinguish between direct hydrogenation (deuteration!) of the coal and the products of pyrolysis and the 'shuttling' of hydrogen atoms between different parts of the pyrolysing coal. The addition to the coal of 5% (wt.% of coal) of either tetralin or pyrite was also studied. A variety of techniques were used to analyse the products of pyrolysis: gas chromatography - mass spectrometry and high performance liquid chromatography for tars; thermal conductivity gas chromatography and high resolution mass spectrometry for gases; methanol densities, microporosities and diffuse reflectance infra red spectroscopy for the cokes (chars); refractive index to determine deuterium in the liquor. An attempt has been made to apply basic thermodynamics to reactions which are likely to occur in the hydropyrolysis of coals. Diffusion and effusion rates for hydrogen and tar molecules have also been estimated.
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Two kinds of coal-bearing kaolinite from China were analysed by X-ray diffraction (XRD), Thermogravimetric analysis-mass spectrometry (TG-MS), infrared emission spectroscopy. Thermal decomposition occurs in a series of steps attributed to (a) desorption of water at 68 °C for Datong coal bearing strata kaolinite and 56 °C for Xiaoxian with mass losses of 0.36 % and 0.51 % (b) decarbonization at 456 °C for Datong coal bearing strata kaolinite and 431 °C for Xiaoxian kaolinite, (c) dehydroxylation takes place in two steps at 589 and 633 °C for Datong coal bearing strata kaolinite and at 507 °C and 579 °C for Xiaoxian kaolinite. This mineral were further characterised by infrared emission spectroscopy (IES). Well defined hydroxyl stretching bands at around 3695, 3679, 3652 and 3625 cm-1 are observed. At 650 °C all intensity in these bands is lost in harmony with the thermal analysis results. Characteristic functional groups from coal are observed at 1918, 1724 and 1459 cm-1. The intensity of these bands decrease by thermal treatment and is lost by 700 °C.