Ventilation in mines, with special reference to mine resistance and fan efficiencies

Until very recently the Theory of Mine Ventilation has been a subject which most investigator. have neglected very badly. Two men, however, cannot b included among them, viz., Atkinson and Murgue, both having contributed classical works... Rateau was another who may be excluded. Nevertheless this does not imply that Mine Ventilation had been neglected in practice. On the contrary, during the period of these disastrous explosions in the eighteenth and nineteenth centuries, the necessity was felt for a plentiful supply of air in mines at any cost. This need was fulfilled by the use of.fans; but, effective ventilation was never coupled with efficient ventilation. When effective ventilation was realized, contentment seems to have. reigned, and the papers of those authors mentioned wer accepted complacently. Thus, although the chemistry of ventilation was well investigated, the theoretical side of the question was neglected. This peaceful state, disturbed by Mr.Clive in 1920, was shattered by Dr.Penman in 1921, when he advocated the abandonment of Murgue's "equivalent orifice" and "orifice of passage ", pressing for a direct method of measuring mine resistance, following the electrical engineers' Ohm's Law. His suggestion was seconded by Dr.Parker later in 1921 and amplified. in 1923 by the Council of the Institution of Mining Engineers which set up a Committee to prepare a foundation for the very necessary research in Ventilation. In 1925 this Committee issued two Reports, in the first of which after revising and summarising previous work, it supported Dr.Penman in his suggestion and fixed standards of measurement; in the second, it pointed out the effects of natural ventilation in the ventilation of deep mines Various other people, notably Professors Briggs and Hay have also agreed with Dr.Penman. In the discussions on the recent papers by the modern writers just mentioned, many laws, modifications of Dr.Penman's variation of Ohm's Law, have been suggested, especially by Professor Briggs, to give some criterion of mine resistance. However, no law or equation seemed favourable to all; there seemed nothing but doubt on every point. In an endeavour to throw some light on this clouded subject, tests were run on various collieries in Scotland and England by Professor Henry Briggs, D.Sc., Ph.D., etc., Williamson, B.Sc., Ph.D., J.S.Penman, B.Sc., Ph.D., and the.writer. The results of this investigation will be described later. It is now necessary to give a fuller account of previous allied work, to which this fragment is added

The Queen's General John Churchill Duke of Marlborough 1650-1722

A catalogue of an exhibition of books, prints, manuscripts, and medals from the department of special collections of the University of Kansas Libraries

DESIGN AND ANALYSIS OF ONE-PIECE 10” CARBON FIBER WHEELS FOR ZIPS RACING ZR20 FORMULA SAE RACECAR

Reducing the weight of a vehicle in racing can substantially improve the vehicle dynamics and general performance capabilities. More specifically, the reduction of the unsprung corner weight can provide noticeable performance gains in handling and responsiveness, leading to a quicker, more agile car due to a lower yawing moment of inertia. Unsprung weight reduction also improves the car’s ability to maintain contact between the tires and the road surface for a more consistent grip. In this project we identified the loads that act on the wheel rims according to the data collected from the sensors in the car’s suspension, and we used that data to design a lighter and stronger carbon fiber wheel to handle those extreme load conditions. Decreasing the weight of the wheel itself (changing materials from aluminum to carbon fiber) will reduce the unsprung corner weight as well as the rotating mass

Detection of Human Influence on a New, Validated 1500-Year Temperature Reconstruction

Climate records over the last millennium place the twentieth-century warming in a longer historical context. Reconstructions of millennial temperatures show a wide range of variability, raising questions about the reliability of currently available reconstruction techniques and the uniqueness of late-twentieth-century warming. A calibration method is suggested that avoids the loss of low-frequency variance. A new reconstruction using this method shows substantial variability over the last 1500 yr. This record is consistent with independent temperature change estimates from borehole geothermal records, compared over the same spatial and temporal domain. The record is also broadly consistent with other recent reconstructions that attempt to fully recover low-frequency climate variability in their central estimate. High variability in reconstructions does not hamper the detection of greenhouse gas-induced climate change, since a substantial fraction of the variance in these reconstructions from the beginning of the analysis in the late thirteenth century to the end of the records can be attributed to external forcing. Results from a detection and attribution analysis show that greenhouse warming is detectable in all analyzed high-variance reconstructions (with the possible exception of one ending in 1925), and that about a third of the warming in the first half of the twentieth century can be attributed to anthropogenic greenhouse gas emissions. The estimated magnitude of the anthropogenic signal is consistent with most of the warming in the second half of the twentieth century being anthropogenic

Orion Spacecraft MMOD Protection Design and Assessment

The Orion spacecraft will replace the Space Shuttle Orbiter for American and international partner access to the International Space Station by 2015 and, afterwards, for access to the moon for initial sorties and later for extend outpost visits as part of the Constellation Exploration Initiative. This work describes some of the efforts being undertaken to ensure that Orion design will meet or exceed the stringent MicroMeteoroid and Orbital Debris (MMOD) requirements set out by NASA when exposed to the environments encountered with these missions. This paper will provide a brief overview of the approaches being used to provide MMOD protection to the Orion vehicle and to assess the spacecraft for compliance to the Constellation Program s MMOD requirements

Digital Imaging and Analysis of Dusty Plasmas

Dust particles immersed within a plasma environment, such as those found in planetary rings or cometary environments, will acquire an electric charge. If the ratio of interparticle potential energy to average kinetic energy is high enough the particles will form either a 'liquid' structure with short-range ordering or a crystalline structure with long-range ordering. Since their discovery in laboratory environments in 1994, such crystals have been the subject of a variety of experimental, theoretical, and numerical investigations. Laboratory experiments analyzing the behavior of dust grains in a plasma rely on optical diagnostics to provide data about the system in a non-perturbative manner. In the past, capturing, imaging, and analyzing crystalline structure in dusty plasmas has been a non-trivial problem. Utilizing digital imaging and analysis systems, data capture, image formatting, and analysis can be done quickly. Following data capture, image analysis is conducted using modified Particle Image Velocimetry (PIV) and Particle Tracking Velocimetry (PTV) algorithms. The data extracted is then used to construct Voronoi diagrams, calculate particle density, inter-particle spacing, pair correlation functions, and thermal energy. From this data other dust plasma parameters can be inferred such as inter-particle forces and grain charges.Comment: 6 pages, Presented at COSPAR '0