THE STRUCTURE AND REACTIVITY OF SOME METALLURGICAL CARBONS

The reactivity and micro-structure of three coals and two cokes used in iron and steel manufacture have been studied by a variety of techniques, including gas sorption analysis, thermal analysis and microscopy. Changes in surface areas and porosities of the coals and cokes during combustion have been determined by a gravimetric nitrogen sorption technique at 77K. The cokes and coals have been studied by thermal analysis under isothermal and dynamic conditions in different gas atmospheres. Rates of reaction have been correlated with surface area changes. Attempts have been made to calculate activation energies from Kissinger plots of DTA data. Microstructural changes in the cokes and coals during carbon burn-off have been investigated by electron microscopy. Relative porosities have been estimated by image analysis. Mechanical strengths of the cokes have been measured and correlated with porosity data. Selected metals in the carbons have been determined by flame photometry, atomic absorption spectroscopy and Mossbauer spectroscopy. The composition of residual mineral matter (ash) has been investigated by X-ray diffraction. The chemical compositions of the coal distillates have been characterised by ir/uv spectrosopy, NMR spectroscopy and by GC-MS techniques. Calorific values of the carbons have been determined. Results are discussed in relation to previous work and to applications 1n blast furnace practice. In coal combustion the surface areas increase during the initial stages of carbon burn-off, reaching maximum at about 50% burn-off before decreasing. The increases are considerably higher at 400° and 500° C than at 300° C for all three coals. Hysteresis data from the sorption isotherms show that the coals develop full ranges of mesa-porosity and some micro-porosity during burn-off at the higher temperatures. However, the coal oxidation is only slightly accelerated, since most of the new surface is located in the micro- and meso- pores where access to atmospheric oxygen is restricted by slow diffusion, so that the earlier stages of oxidation are approximately linear with time. This improves our knowledge of current empirical industrial carbon solution tests. There is comparatively little change in surface during the coking of the Coals at 1000° C and only restricted sintering of the coal ashes at 300- 500° C. In the combustion of the cokes in carbon dioxide at 1000° C the maxima in surface areas occur within 25% burn-off. However, one of the cokes shows a second maximum at later stages of burn-off, ascribed to the European component in the parent coal blend. This gives a more uniform rate of burn-off which is advantageous industrially.British Steel Corporation, Teesside Laboratorie

Attitudes of Students Studying Huxley\u27s Brave New World: An Analysis

The central concern of this study will be this: will the study of a specific work of literature have a statistically significant effect upon the attitudes of students toward the problems dealt with in that work? This problem grew out of a consideration of the difficulties involved in an earlier and now discarded study. A choice of weather to use Aldous Huxley’s point or his Brave new world was to be made, and point counterpoint seemed the better choice for that study; but the book chosen has to be taught to freshman English students. The immediate problem was one of whether point counterpoint could be taught successfully to these students

Paper Session II-A - Space Station Payload Adaptation System

The internal, pressurized payloads used on early flight of the Space Station will consist of many payloads and on-going investigations carried over from the Shuttle. Therefore, the Space Station will require a small payload carrier that can adapt Shuttle payloads to the Space Station and also offer these transitional payloads the full advantages of Space Station capabilities such as longer microgravity periods, increased crew availability, and increased resources such as power, data and heat rejection capability. An end-to-end systems analysis of payload integration activities dictates the need for improved containers to fully exploit Space Station resources, improved operation efficiency and increase design flexibility. In response to this need, improved payload containers as well as a structure to adapt these and existing payload containers to the Space Station rack system have been designed

Palatability of teff grass by horses

Most forages commonly used to feed horses have potential detriments including blister beetles or excessive fiber concentrations. Teff grass (T), a warm-season annual forage, has the potential to be a good alternative for horses because of its lack of observed disorders. Our objective was to compare preference by horses for T harvested under different conditions with that of bermudagrass (B) harvested at two maturities. Six different forages were evaluated: T harvested at the late vegetative stage (TLV), at late bloom but that incurred 33 mm of rainfall between mowing and baling (TLBR), with caryopsis visible (TES), or at soft dough (TSD), and B harvested at late vegetative (BLV) and mid-bloom (BMB) growth stages. Five mature horses were used in a balanced incomplete block design where each horse received a different combination of 4 forages each day for 6 d. The 4 different forages were suspended in hay nets in each corner of each stall, and each hay was offered at 50% of the average daily hay consumption measured during a 12-d adaptation period. Forage preference as measured by individual forage dry matter (DM) consumption (kg and % of total DM consumed across the 4 forages) was greatest (P \u3c 0.05) from TLV followed by BLV. Preference (kg and % of total DM consumed) of BMB was greater (P \u3c 0.05) than that of TMBR, TES, and TSD, which did not differ from each other (P ≥ 0.63). Therefore, within a specific growth stage, horses apparently preferred teff grass, but effects of maturity and rainfall had a more dramatic effect on preference by horses than forage species