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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Investigation of the characteristics of a coal burning Rijke type pulsating combustor

Carvalho, Joao Andrade 05 1900 (has links)
No description available.
262

A study of the thermodynamic properties of synthetic fuels and coal derived liquid mixtures

Siddiqi, Sohail Azeem 05 1900 (has links)
No description available.
263

Acoustical properties of coal

Chew, Chye Heng 08 1900 (has links)
No description available.
264

Optimisation of pillar dimensions in sedimentary strata, with particular reference to coal and strong limestone

Thin, Iain Granham Traquair January 1994 (has links)
No description available.
265

The removal of volatile alkali salt vapours from hot coal-derived gases

McLaughlin, John January 1990 (has links)
No description available.
266

Dense phase pneumatic conveying of fine coal

Ling, S. J. January 1988 (has links)
No description available.
267

The application of seismic surveys to the evaluation of shallow coal deposits

Brabham, Peter John January 1986 (has links)
The viability of using surface seismic techniques in the exploration of shallow coal deposits in the UK is investigated. The geological factors that affect the economic viability of a prospective site are the overburden ratio and the presence of faulting, drift channels and previous mine workings. The seismic refraction technique using both congressional (P) waves and shear (S) waves is used and also the P wave reflection technique. The P wave source used is explosive and the shear wave source is a horizontal hammer. Seven site surveys are described, six in North East England, and one in the North West. The refraction technique using the Plus-Minus and Generalized Reciprocal Methods of interpretation is used to locate faults, estimate drift cover thicknesses and pinpoint areas of previous opencast excavation. Faults are located by a change in refractor velocity, or by a sudden change in refractor depth. Shear waves display a greater ability to image sharp depth anomalies than P waves, due to the greater velocity contrast between consolidated and unconsolidated rocks that S waves exhibit. S waves are better lithological indicators than P waves as there exist distinct ranges of S wave velocities for unconsolidated (150 to 400m/sec) and consolidated (650 to 1400m/sec) rocks. The fundamental problem with shallow reflection surveys on land is that the shallow reflections occur at the same time as surface waves and ground roll. The reflection technique is used to locate faults and detect the boundaries of old mine workings. No reflections shallower than 70m are recorded, and in areas of thick glacial drift cover no frequencies higher than l00Hz are detected. The results of the survey to locate positions of old mine workings are inconclusive, although some features seen on the final sections could be related to boundaries between unworked and worked strata.
268

Spectrochemical analysis of whole powdered coal

Parry, Huw Gareth Michael January 1987 (has links)
The analysis of coal without sample dissolution was investigated by introducing coal slurries, into a variety of atom cells including electrothermal atomisation atomic absorption spectroscopy (ETAAAS), inductively coupled plasmas and direct current plasmas for atomic emission spectroscopy (ICP-AES, DCP-AES) and inductively coupled mass spectroscopy (ICP-MS). All the analyses were calibrated using aqueous standards. Slurries were injected into an electrothermal atomiser. The effects of furnace programme, background correction and air ashing were investigated. As, Se, Cd and Sb were successfully determined in a variety of certified reference material coals. For As the coal was slurried in nickel nitrate, magnesium nitrate, nitric acid and ethanol. Continuiun source and Smith-Hiefije background correction were compared for correction of a broadened Al line interference at the As (193.7 nm) line. Only the latter was effective. Smaller Se signals were obtained from coal compared to aqueous solutions. Iron coal produced structured background and hence overcorrection. The successful method introduced air into the ash stage. Both DCP and ICP techniques yielded good agreement with certificate values provided that the particle size was reduced to below 16 um and 10 um respectively. Simplex optimisation identified the critical parameters for aluminium determinations as being high injector flow rate and low observation height. Preliminary investigations of slurry atomisation using ICP-MS and 0.2% m/v slurried coal gave no blocking. Contamination from zirconia grinding elements used to comminute coal was investigated using laser ablation ICP-MS. Excitation temperature (Texc), ionisation temperature (Tion) rotational temperature (Trot) and electron number density (ng), were measured for different slurry concentrations (1-30% m/v) in the ICP. Depending on themometric species used, Texc may decrease with slurry concentration, but there were no similar decreases in Tion, T(rot) and ng. Observed decreases in analyte emission with increased sample loadings (> 10%) were shown to be caused by transport effects.
269

Spectroscopic studies of coal and an ESR study of mono and dicarbonyl radical cations

Portwood, Lynn January 1987 (has links)
Part I - ESR spectra of pure coals, oils and tars are presented; their g values and linewidths are calculated. Almost all the spectra are single, broad resonances; but one coal, Hucknall Coal, exhibits a two line spectrum, a narrow line superimposed on a broad line. On admission of oxygen the narrow line is reversibly lost. On the addition of various solvents to the samples, in most cases, an irreversible loss in ESR signal intensity was observed. There seems to be no direct correlation between which solvent is added to which coal and the effect on the ESR signal intensity. Infra-red spectra of pure coals are studied, both as pressed discs and thin films, and a method for the preparation of these discs and films is given. Solvent addition experiments were undertaken and the results show the breaking of weak coal/water hydrogen bonds and the formation of stronger coal/solvent hydrogen bonds. Part II - ESR spectra of the radical cations of several mono and dicarbonyl compounds are presented and interpretation of these spectra are given. For most compounds the parent radical cation is seen, with the spin on oxygen. The cyclic dicarbonyls show the σ-bonded structure for the cation with coupling to the protons δ to the spin. Some non-aldehydic dicarbonyls show a rearranged structure with the spin on carbon. The aldehydic dicarbonyls all show, in addition to the parent radical cation, lines due to an acetal type species, as yet unidentified. Some compounds containing nitrogen or sulphur in addition to oxygen have the spin localised onto these alternative heteroatoms.
270

The colliery cottage 1830-1915, the great northern coalfield

Brown, Helen Diana January 1988 (has links)
The North East of England experienced its greatest period of economic growth during the period 1830-1915. This economic prosper .- ity was closely related to coal mining, with a corresponding increase in the number of coal miners who had to be accommodated near the collieries. This explains the large number of colliery cottages constructed, and their location often in previously uninhabited areas. This thesis seeks to establish the seminal plan form of the Colliery Cottage of the Great Northern Coalfield, to trace .its development, to examine the social context and analyse the settlement pattern. Part One sets the scene for the study with a historical background of the Great Northern Coalfield, identifying the demographic profile of the community and examining its main characteristics: economic, social, historical and health. Part Two is concerned with the colliery cottage itself and presents a catalogue of cottage types. Drawn from a wide variety of sources, selected examples of different categories of colliery cottage have been recorded to a standard format. An analysis of the drawings gives a comprehensive picture of origin and development of this building type which holds a special place in the history of the North East.Part Three looks at detail design: the fabric of the colliery cottage, the materials, construction methods and the interior. Part Four describes the colliery villages. Using Ordnance survey maps as the main reference point, the various settlement patterns have been traced from agricultural origins: the square, the row and the grid pattern of the Bye Law street through to the socalled enlightened plan which emerged towards the end of the study period. The development cost of the settlement and its financial organisation are also considered. The thesis by its very nature is a synthesis of a range of knowledge fields:historical, technical, aesthetic and social. The approach in this case has been from a broad perspective and with knowledge of miners' cottages in other areas. It is hoped that in this way a complete picture of the colliery cottage within its historical context has emerged.

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