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Though the definition of equilibrium moisture content of porous materials is straight forward from the point of view of equilibrium thermodynamics, experimental determination of this quantity may not always be easy. Many factors play their roles from an experimentalist's point of view. Hysteresis, the reference dry state, the initial moisture content, the history of the test specimen, the size of the test specimen, the drying technique and drying temperature - all influence the value that is arrived at by an experimentalist. This paper reports results from several series of measurements on gypsum board, eastern white pine, aerated concrete, and calcium silicate brick using the ASTM Standard C 1498 in the hygroscopic ranges and pressure plate techniques above the hygroscopic range of equilibrium moisture contents. These results show the ambiguities that may surround the experimental definition of equilibrium moisture content. The results presented in the paper demand a few refinements in the existing ASTM Standard C 1498 as well as in the procedure that is used in the pressure plate method. The paper proposes a few refinements for both. The need for the development of an ASTM standard for the pressure plate technique is identified., Also published in Symposium on Heat, Air and Moisture Transport Properties of Building Materials, ASTM, Toronto, Ontario, April 2006, pp. 1-18.

SRI International has prepared dynamically generated silica samples since 1980 for the National Institute of Occupational Safety and Health (NIOSH) and the American Industrial Hygiene Association (AIHA) Proficiency Analytical Testing (PAT) programs. Aerosol-generated samples were developed in 1980 to more closely approximate real world samples and to improve intrabatch precision. Liquid-generated samples may provide tighter control limits, and this method has been reexamined as the generation procedure of choice. Sample preparation procedures have also been investigated to minimize analytical uncertainty and, hence, obtain a true evaluation of the sampling error. Samples were analyzed by SRI, NIOSH, and the Wisconsin Occupational Health Laboratory, using X-ray diffraction or Fourier transform infrared spectrometry (FTIR). Results were plotted and statistically evaluated, then compared to the existing PAT interlaboratory database.

In this experimental study, the effects of vacuum process on mechanical and physical properties of concrete were investigated by comparing mechanical properties of vacuum processed and half vacuum processed concrete specimens with those of control specimens. Vacuum equipment was used to apply vacuum to fresh concrete in order to extract water from floor concrete. Compressive strength and some other test results obtained from both vacuum processed and plain concrete core specimens were evaluated and then compared. Test results have shown that the compressive strength of vacuum processed concrete specimens increased substantially due to the decrease in water/cement ratio by dewatering process. The effects of the process on compressive strength at early ages and on surface placement are much more pronounced. Some of the other properties such as dry density, unit weight, surface hardness, and surface porosity are also improved by vacuum dewatering process.

Bituminous aggregates from a total of 52 sources located in Texas, Oklahoma, Arkansas, New Mexico, and Missouri were evaluated using both Micro-Deval and magnesium sulfate soundness tests. Each aggregate was also characterized using petrography, absorption, and specific gravity. Findings showed that Micro-Deval test is a more repeatable test than the soundness test. Micro-Deval showed a fair to good correlation with soundness and an improved correlation was observed when used along with aggregate absorption values. It is concluded that further research is needed to completely replace soundness tests but the Micro-Deval test could be used as a good quality indicator tool.

Research was undertaken using thin sections and immersion mounts with the objective of using a modified line count procedure for the quantitative petrographic determination of fly ash and ground-granulated blast furnace slag (GGBFS) in hardened concrete and blended cements. The line method used in this study is a variation of standard microscopic point count methods and yields an average number frequency that is a linear function of the weight percent of fly ash or GGBFS of total cementitious materials. Multiple traverses were counted on thin sections of concrete over areas of paste only and in immersion slides of blended cements containing known amounts of fly ash and GGBFS. The average number of particles in a traverse was computed, the traverse length being equal to the width of the field of view of the petrographic microscope. For hardened concrete, only pozzolan particles were counted. For blended cements, all particles were counted and the ratio of pozzolan particles to total particles was determined. A linear relationship between the average number of pozzolan particles for a traverse line and the weight percent of pozzolan makes it possible to estimate the fly ash and GGBFS content of unknowns. Results of the research indicate that the line method is a rapid and accurate method for petrographic determination of fly ash and GGBFS in hardened concrete and blended cements. This technique and variations of it have been used by other researchers and it has the potential to be a standard test procedure.

Five hexagonal ducts constructed from AISI 304 stainless steel in the annealed state were removed from rows 8–14 of the EBR-II fast reactor after many years of irradiation to study the effect of atomic displacement rate on void swelling. For this objective it was important to assure that the observed differences in void swelling were not strongly influenced by variations in helium/dpa ratio. The two major contributions to helium production arise from the nickel and boron content of the steel. However, the boron content was unspecified and therefore unknown, but it was determined from an unirradiated archive duct by converting a well-defined fraction to helium and then measuring the helium content using isotopic dilution mass spectrometry. The same technique was used to measure the total helium in the irradiated duct specimens. After separating the boron contribution from the total measured helium it was possible to determine the contribution from various fast and thermal neutron interactions with the other major elements in the steel and compare the helium generation with predicted values. One important conclusion of the study is that the range of He/dpa ratios over the five subassemblies was not very large, allowing the observed changes in swelling to be attributed primarily to variations in displacement rate and temperature.

Significant advances have been made in heavy duty diesel engine technology to meet increasingly stringent environmental regulations for emissions. Today's heavy duty diesel engines are being designed with lighter and softer metals, greater turbocharging, increased combustion controls, and new emission reduction equipment. The cooling systems contained in these vehicles are similarly being impacted by smaller designs, new cooling system configurations, and increased usage of lighter, softer metals. Vehicle thermal loads have significantly increased due to increased power densities, higher engine temperatures, and greater metal-coolant fluxes which places greater emphasis on oxidation/thermal stability, and high temperature corrosion protection performance of the coolant. Other operating conditions (coolant flow rates, turbulence, pressure drops, deaeration) are also becoming more severe calling for improved erosion-corrosion protection, cavitation protection, and elastomer, seal, hose compatibility. This paper reviews the changes in heavy duty diesel engine technology and provides information on coolant performance in 2002-4 emission compliant engines. Predictions are also made on future engine technology and next generation engine coolants.

The suction technique is a method from soil science that is used for the study of moisture storage capacity in porous construction materials at high relative humidity levels (above approximately 93 %). The samples to be studied are placed in a pressurized container (an extractor) on a water saturated ceramic disk or membrane. The pressure corresponding to a certain relative humidity level is established and moisture is expelled from the samples until moisture equilibrium is reached. This paper presents two adjustments to this method and their applicability. The first adjustment is a new procedure for determining the equilibrium moisture content of samples during the experiment. The method (referred to as the balance method) is to simply keep track of all water entering and leaving the system and use these data to estimate the moisture content of the samples. The advantage of this approach is that the experiment does not need to be stopped and restarted for each relative humidity level tested. The main disadvantage of the method is that the estimation of the moisture content in the samples depends on a correct estimation of the moisture content of the ceramic disk. The second adjustment is the development of a pressure regulation system that keeps the pressure constant (±0.015 bar) within an extractor for weeks.

Thermal analysis combined with composition analysis has been used in this work to identify evolved gas when burning household waste. Thermogravimetry (TG) coupled with Fourier transform infrared (FITR) spectroscopy and mass spectrometry (TG-FTIR-MS) offers structural identification of compounds evolved during thermal processes. Carbon, hydrogen, and nitrogen elemental analysis and XRD offers raw materials information. All these combined can help to evaluate the chemical pathway for the degradation reactions by determining the decomposition products. For comparison purposes, emitted species concentrations are measured with multiple-sensors when burning household waste in a lab-scale fluidized bed combustor. There is excellent agreement between the two different approaches. The measured results also provided some insight into burning household waste as an energy source in large-scale incinerators.

Structural silicone sealants have been used since the mid 1960s in the construction industry to attach glass to curtainwall framing systems. Design standards for these sealants have been in practice since the early 1970s and continue to be developed today. Most of these standards require tests that are based on a one-time destructive test of the joint material in tension. The industry established structural silicone design stress is intended to be reached only during the highest windload for the specified return wind period. The existing practice has had great success because the industry guidelines minimize stress on the silicone, and dictate quality assurance procedures that are instituted by curtainwall producers. In real life situations the sealant is additionally fatigued through a cyclic shear mechanism caused by daily thermal movement differences between the glass pane and the aluminum frame. This paper discusses a method for testing the effect of fatigue in sealants used in structural designs and comparing the data to control samples.

The preparation of closed-cell foam insulation test specimens can affect the results of a number of hygrothermal property measurements. In particular, the thickness of the destroyed surface layer affects the measurement of gas diffusion coefficients and thermal conductivity. Multiple specimen preparation methods are in use, as well as multiple methods to measure the thickness of the destroyed surface layer. A ruggedness test, including an interlaboratory comparison, was conducted by an ASTM technical committee to examine the variations due to both of these factors. The results are important in understanding the likely range in values for each preparation technique. The results also demonstrate a sensitivity to the measurement technique.

An investigation was made into the effects of flux formulation and after brazing residue on the pitting potential of the aluminum surface in various types of coolants during laboratory evaluations. Samples of CAB brazed radiator header alloy aluminum, with various flux loadings, were supplied by Behr and the Ford Motor Company. The flux is generally in the form of potassium fluoroaluminate, general formula K1–3AIF4–6.xH2O. The samples in the flux loading study were all passed through the brazing ovens with the following flux loadings: • No flux, • Half the regular amount of flux, • The regular amount of flux, • Double the regular amount of flux, • Regular amount of flux over half of the surface area. The individual coolants used in the flux loading study were 25 % volumes of the following, each with 100 ppm of chloride: • Conventional, • Hybrid (HOAT), • Organic Acid (OAT), • Modified Organic Acid (MOAT). In the flux composition study, different compositions of potassium fluoroaluminate from three different suppliers were evaluated with hybrid type coolant. All the aluminum samples were run according to a Ford Laboratory Test Method (FLTM) BL105-01 “A Rapid Method to Predict the Effectiveness of Inhibited Coolants in Aluminum Heat Exchangers” [1]. The samples were heated and boiled in coolant for 1 h. The temperature was lowered to 70°C and the samples were electrochemically tested by either potentiodynamic polarization or modified Ford FLTM BL105-01. Each coolant at the end of the test was submitted for chemical analysis of fluoride content. The electrochemical results of the flux loading study showed that the higher the flux loading on the aluminum header material, the easier it is to initiate corrosion. Chemical analysis showed the presence of significant quantities of fluoride in the end of test fluids. As the only fluoride-containing component of the system is the flux residue, it was concluded that fluoride leached from the flux residue. The second study showed that not all potassium fluoroaluminate brazing flux is alike. Samples of three fluxes from three different suppliers of the same loading on aluminum were tested with hybrid coolant. When subjected to heating and potentiodynamic polarization, significantly different results were obtained from the three different fluxes.