Raman spectroscopy for the analysis of cements – past, present and future

Until recently there has been a common held misconception that Raman spectroscopy of cements is not possible, or at least so inconvenient as to make it impracticable. However, whilst not a routine analysis method Raman analysis of cementitious materials is possible, provided that suitable consideration is given to the technique’s limitations. This paper will chart the history of Raman spectroscopy applied to cementitious systems, review recent developments in the field and look towards possible future developments. Raman spectroscopy is a vibrational spectroscopic technique often considered complementary to infra-red spectroscopy, and provides information on the short-range order and local bonding in materials. Furthermore, the common coupling of a spectrometer to an optical microscope enables spatial resolution in the order of microns, whilst the rapid analysis times and low sensitivity towards water enables in-situ analysis of hydrating pastes. Furthermore, the technique is particularly sensitive to sulphate and carbonate environments, and is semi-quantitative

The Marital and Physician Privileges—A Reprint of a Letter to a Congressman

I am much disturbed by the treatment given to privilege, inMoore and Bendix, Congress, Evidence and Rulemaking. 1 My disturbancecenters mainly on their treatment of the marital and physicianprivileges

The Marital and Physician Privileges—A Reprint of a Letter to a Congressman

A design of computer systems, that effectively supports the user, is a major goal within human-computer interaction. To achieve this, we must understand and master several tasks. These tasks concern firstly what to develop and secondly how to develop the system. The design and implementation of effective and efficient user interfaces is a prerequisite for the successful introduction of computer support in the medical domain. We base our work on a fundamental understanding of cognitive aspects of human-computer interaction, as well as on detailed analysis of the specific needs and requirements of the end users, i.e., the medical professionals. This thesis presents several approaches for development of systems for computer-supported work in health care. The solutions described concern vital problem areas: (1) the focus on the work tasks to be performed, (2) the cost of software and the way competition works in a networked world. Solutions to these problems can lead to more usable systems from a user's perspective but may also change the nature of computer applications

Solidification of APC residues using PFA

A pulverised fuel ash (pfa) classed as a waste due to high loss on ignition (LoI) was blended with waste alkali and used to solidify air pollution control (APC) residue from a waste incinerator. The resultant samples were tested for compressive strength and characterised using thermogravimmetric analysis (TGA). The effects of various variables including; l/s ratio, APC content, curing temperature and alkalinity of the liquid phase were examined. Results showed that a lower l/s gave higher compressive strength, analogous to that seen for cement mixes. Curing at slightly elevated temperatures were necessary for setting of the mixes within 7 days. An alkaline liquid fraction increased early age strength. The %(w/w) APC content showed no clear correlation with compressive strength results, but some APC was necessary for the mix to set. Resulys suggest the optimum APC content for compressive strength and solidification may be between 10-20%

Conservation Equations of a Viscous, Heat-Conducting Fluid in Curvilinear Orthogonal Coordinates

Conservation equations of viscous heat conducting fluid in curvilinear orthogonal coordinate

Community Clinical Pastoral Training -- A Success for Ecumenism in Shreveport

A review of the seven years\u27 activity of the Shreveport Medical Society\u27s committee of Medicine & Religion which lead to the formation of the Clinical Pastoral Training Program, is presented by the co-chairmen of the committee

Structure, bonding and morphology of hydrothermally synthesised xonotlite

The authors have systematically investigated the role of synthesis conditions upon the structure and morphology of xonotlite. Starting with a mechanochemically prepared, semicrystalline phase with Ca/Si=1, the authors have prepared a series of xonotlite samples hydrothermally, at temperatures between 200 and 250 degrees C. Analysis in each case was by X-ray photoelectron spectroscopy, environmental scanning electron microscopy and X-ray diffraction. The authors’ use of a much lower water/solid ratio has indirectly confirmed the ‘through solution’ mechanism of xonotlite formation, where silicate dissolution is a key precursor of xonotlite formation. Concerning the role of temperature, too low a temperature (~200 degrees C) fails to yield xonotlite or leads to increased number of structural defects in the silicate chains of xonotlite and too high a temperature (>250 degrees C) leads to degradation of the xonotlite structure, through leaching of interchain calcium. Synthesis duration meanwhile leads to increased silicate polymerisation due to diminishing of the defects in the silicate chains and more perfect crystal morphologies

Rain-induced spring wheat harvest losses

When rain or a combination of rain and high humidity delay wheat harvest, losses can occur in grain yield and/or grain quality. Yield losses can result from shattering, from reduction in test weight, and in the case of windrowed grain, from rooting of sprouting grain at the soil: windrow contact. Losses in grain quality can result from reduction in test weight and from sprouting. Sprouting causes a degradation of grain proteins and starches, hence flour quality is reduced, and the grain price deteriorates to the value of feed grain. Although losses in grain yield and quality are rain-induced, these losses do not necessarily occur because a standing or windrowed crop is wetted by rain. Spike water concentration in hard red spring wheat must be increased to about 45-49% before sprouting is initiated in grain that has overcome dormancy. The time required to overcome this dormancy after the cultivar has dried to 12 to 14% water concentration differs with hard red spring cultivars. The effect of rain on threshing-ready standing and windrowed hard red spring wheat grain yeild and quality was evaluated. A goal was to develop the capability to forecast the extent of expected loss of grain yield and quality from specific climatic events that delay threshing

The water factor in harvest-sprouting of hard red spring wheat

Sprouting in unthreshed, ripe, hard red spring wheat (Triticum aestivum L.) is induced by rain, but sprouting does not necessarily occur because the crop is wetted. The spike and grain water conditions conducive to sprouting were determined in a series of laboratory experiments. Sprouting did not occur in field growing wheat wetted to 110% water concentration until the spike water concentration was reduced to 12% and maintained at this concentration for 2 days before wetting. When cut at growth stage 11.3, Feekes scale, Saratovskaya 20 (USSR) sprouted after 4 days drying, Olaf and Alex between 7 and 15 days drying and Columbus, recognized for its resistance to harvest time sprouting, after more than 15 days drying. Sprouting potential was enhanced after 4 wetting drying cycles in which any wetted interval was too brief to permit sufficient water imbibition to initiate sprouting. At harvest ripeness, grain water concentration exceeded spike water concentration by 0.7 percentage units. Following 6 months storage, 20% of the kernels in 300 spike bundles (simulating windrows) sprouted within 28 hrs after initiation of wetting to saturation (150% water concentration). Ninety percent sprouting occurred within 8 days in bundles maintained at 75% water concentration and higher, but less sprouting occurred in bundles dried to 50% water concentration before resaturation