bluuebunny/crossref_metadata_2025 huggingface dataset:
Management, Marketing, Financial, and Legal Issues
Authors: Humber JN
Published: March 2009

Initially, resource recovery efforts focused on the development of technology. Two years ago, it became apparent that the problem to be solved was not just with supply (technology), but also with demand (markets). Markets for energy and secondary products are indeed major issues. As the implementation effort has matured, it has become apparent that technology and markets are not the only problems. The other problems include economics, marketing, financing, management, and complex legal issues. This paper addresses these issues.
Unit Operations for Nonferrous Metals Recovery
Authors: Makar HV , DeCesare RS
Published: March 2009

This paper describes some of the techniques, or unit operations, which appear to have promising potential for commercial recovery of nonferrous metals from municipal refuse. Included are the wet processes of jigging, water elutriation, and heavy media and the dry processes of eddy-current separators and electrostatic separators. A brief description of the operating principal of each is given with typical data to illustrate operating performance. The processes described have been used in various commercial-scale operations or are scheduled for use in commercial-scale operations in the near future.
Opportunities for Plastics in Resource Recovery
Authors: Kaufman FS
Published: March 2009

This paper is a review of plastic industry sponsored studies 1966–1974 concerning the disposal, recycling, and recovery of plastics from solid wastes. Due to inherent problems in separating clean fractions of specific polymers from a heterogeneous mixture of municipal solid wastes, the recovery of energy appears to offer the greatest potential in plastics resource recovery. Nevertheless, the plastics industry continues to investigate new technology aimed at sorting plastics from mixed wastes and to search for markets for these materials.
Report on the Paper Workshop
Authors: Arnold EW
Published: March 2009

The percentage recycling of paper in the United States has recently increased, reversing the previous downward trend. Old corrugated containers appear to be recyclable at increasing rates without major new technology or incentives needed. Old newspapers are readily recycled, but new cleaning and contaminant control technology are needed to allow their use in the applications where the largest additional consumption would be available. Mixed waste paper represents the greatest challenge for increased recycling as there are substantial technical and economic factors to be resolved if its consumption is to be markedly increased.

Recommendations included the preparation of information kits for aiding municipal collection of segregated wastepaper, for assembling background information on the recycling technology of selected grades, and an analysis of the impact of various possible incentive programs.
Applications of Neutron Radiography to Histopathology
Authors: Boyne PJ , Whittemore WL
Published: March 2009

This paper describes a four-year study of the application of neutron radiography to histopathology using an approach directed toward improvement in histologic sectioning, staining and tissue preparation techniques, and refinement in the application of neutron radiography in three areas: 1. characterization of normal tissues of the facial bones and jaws, 2. diagnosis of intraosseous tumors and a delineation of the invasion of the tumor into the surrounding bone, and 3. the study of metallic semiburied implants attached to bone of the jaws.

It was found to be possible, through the application of these techniques, to determine the presence of intraosseous tumor tissues and to determine the exact extension of the tumor tissue along the marrow vascular spaces and the neurovascular bundles of the bone. Additionally, it was found to be possible to delineate various normal anatomic structures of the facial bones and surrounding soft tissue, and to study the interface between semiburied metals and the surrounding bone and surrounding soft tissue.

It is felt that neutron radiography will provide a significant diagnostic tool in research and in surgical pathology as an adjunct to the usual microscopic method of tissue examination, and additionally in the study of osseous-soft tissue interface with various types of metal implants.
Regulatory Control for Neutron Radiography
Authors: Kerr GW
Published: March 2009

This paper discusses the regulatory framework which exists for the control of sources of radiation which are used in the field of neutron radiography. The paper covers those sources (reactors, subcritical assemblies, special nuclear material, byproduct material, and neutron generators) which are subject to AEC control. In addition, those sources of radiation (accelerators, high energy X-ray machines, and naturally occurring radioactive materials) which are regulated by Agreement States are discussed. The regulatory activities of the Non-Agreement States as they relate to non-agreement sources of radiation are increasing and are also discussed.
ASTM Activities in Neutron Radiography
Authors: Haskins JJ
Published: March 2009

Neutron radiography emerged from the laboratory into an NDT environment that demanded standards for quality and performance. Many NDT areas were established before the advent of these standards. Neutron radiography, on the other hand, faced immediate pressure to produce standards in the shortest possible period of time. To further complicate matters, neutron radiography began its commercial life in high reliability aerospace applications which demanded rigid controls. In response to this obvious need the American Society for Testing and Materials has provided the formal mechanism for producing these standards since 1971 when Committee E-7 on Nondestructive Testing established section E07.01.02.
Neutron Radiographic Nondestructive Evaluation of Aerospace Structures
Authors: Dance WE
Published: March 2009

Neutron radiography with source intensities which are moderate relative to those of reactor neutron sources was found to be effective for non-destructive inspection of a variety of aerospace structures. By using either 2 mg of the isotope californium-252, or a 3-MeV Van de Graaff accelerator as neutron source, the technique was found particularly suited to evaluation of adhesive bonds in metal honeycomb and phenolic fiberglas-to-metal structures. Adhesive flaws in a variety of bonded assemblies, including a set of test panels with built-in adhesive voids and unbonds, were detected by neutron radiographic inspection. In addition, detection of corrosion hidden within metal aircraft assemblies appears to be a promising application of neuron radiography. Corrosion products introduced into one such structure in the laboratory to simulate corrosion from a field situation were radiographically imaged for sizes ranging down to 0.030 in. in diameter and 0.002 in. in thickness. It is expected that with continued improvements in imaging techniques and mobility of neutron sources for radiography the technique will gain widespread usage for routine nondestructive inspection of many types of structures.
Neutron Radiography with a Van de Graaff Accelerator for Aerospace Applications
Authors: Swanson FR , Kuehne FJ
Published: March 2009

The objective of this effort was to develop a thermal neutron radiography capability based on our 3-MV Van de Graaff research accelerator, and to apply it to company-related aerospace inspection problems. The research conducted for determining an efficient system design, its final design features, and radiography beam specifications are explained. An example of its use in providing inspection information for the design of a space vehicle heat pipe system is presented.
Californium-Based Neutron Radiography for Corrosion Detection in Aircraft
Authors: John J
Published: March 2009

In support of an overall program aimed at minimizing disassembly and reducing inspection time during aircraft maintenance, a series of projects has been carried out to determine the feasibility of applying neutron radiographic techniques to the nondestructive (NDT) inspection of aircraft and aircraft components. These investigations have clearly demonstrated the superiority of neutron radiography over all other NDT techniques in its ability to detect surface and subsurface corrosion in aircraft structure. This capability is particularly significant where the corrosion is hidden behind thick metallic structural members. The neutron radiographic technique has been applied successfully to detect corrosion in the wing tank of E-2C, C-130, and DC-9 aircraft; rear stabilators of F-4 and F-111 aircraft; aft spar, starboard and port wing, and rudder of the F-8; fuselage skin of the 727; rotary blades of AH-1 and SH-3 helicopters; rotary tail flaps of the UH-2 helicopter; and nose landing gear of A-7 aircraft.
Nuclear Applications of Neutron Radiography and Gaging
Authors: Haskins JJ
Published: March 2009

This paper briefly describes applications of neutron radiography and gaging to nuclear components. Neutron-based examinations have the unique ability to discriminate between isotopes and to inspect radioactive materials. Applications of neutrons to radiography and gaging include neutron transmission, neutron scatter, neutron production, and measurement of radiation produced by neutron interactions.
Miscellaneous Applications of Neutron Radiography
Authors: Underhill PE , Newacheck RL
Published: March 2009

This paper presents a cross section of neutron radiographic applications experienced by Aerotest Operations, Inc., a production neutron radiographic facility. The purpose of this paper is to demonstrate the breadth of industrial interest in this relatively new nondestructive technique.
Testing for Moisture Content in Foods by Neutron Gaging
Authors: Helf S
Published: March 2009

Neutron gaging was applied to the testing for moisture content in bulk powdered foods and in canned Army field rations. The technique is based on the moderation or thermalization of fast neutrons by hydrogenous matter and the measurement of thermal neutron intensity as a function of moisture content. A small californium-252 capsule, of approximate output 107 neutrons per second, was used as the source of fast neutrons.

It is concluded that a fast neutron moderation technique is feasible for the nondestructive measurement or control of moisture or both in near-dry bulk powdered foods. Samples must be measured under identical geometric conditions, that is, uniform bulk density and volume using a standard metal container or cell. For canned or otherwise prepackaged rations, measurement of moisture is interfered with by variations in fill weight among cans or packages of the same product. A gamma-ray attenuation gaging method proved to be of insufficient sensitivity to correct for fill weight variation and was further complicated by nonuniformity in can wall dimensions. Neutron gaging, however, appears to be quite useful for monitoring a standard packaged item for fill weight since the neutron signal is virtually unaffected by variations in container dimensions. The radiation dose imparted to a sample or package of food subjected to such a test is judged to pose no threat to humans from subsequent consumption of the food. An estimate is given for the cost range of a commercial neutron gage and of encapsulated radioisotopic neutron sources.
Single Specimen Tests for JIc Determination
Authors: Clarke GA , Andrews WR , Paris PC , Schmidt DW
Published: March 2009

A JIc test procedure using a single deeply cracked specimen is proposed. The crack extension is measured by partially unloading the specimen to determine the elastic compliance. JIc tests were made using ASTM A469 steel. Compact specimens from 1/2T to 5T were tested. No size effect was found. Results from two independent laboratories are presented and are in agreement. The errors due to simple formulation of JI calculation, periodic partial unloading, and simplified analysis for the extension of deep cracks in compact specimens are explored. The measurement point of crack extension for establishing JIc is discussed. The results indicate that a practical and effective single specimen test procedure has been developed.
Elastic Plastic (JIc) Fracture Toughness Values: Their Experimental Determination and Comparison with Conventional Linear Elastic (KIc Fracture Toughness Values for Five Materials
Authors: Logsdon WA
Published: March 2009

Good agreement was found between elastic plastic (JIc) and previously developed conventional linear elastic (KIc) critical fracture toughness values for five materials. The materials investigated included four rotor forging steels (ASTM A471 Ni-Cr-Mo-V, ASTM A469 Ni-Mo-V, ASTM A470 Cr-Mo-V, and AISI 403 modified 12Cr) plus an ASTM A217 21/4Cr-1Mo cast steel. A resistance curve test technique recently developed by Landes and Begley was employed to obtain the JIc fracture toughness values. Elastic plastic fracture toughness tests were performed with 1-in.-thick compact tension specimens at a minimum of three temperatures per material, the highest temperature being that where upper shelf fracture toughness behavior was first expected. The fine agreement between the elastic plastic and linear elastic critical fracture toughness values for this class of steels further supports the realization that the elastic plastic JIc fracture criterion, based largely on the path independent J-integral proposed by Rice, extends the concepts of linear elastic fracture mechanics into the elastic plastic fracture regime. Thus, it is now possible to obtain critical fracture toughness values with small specimens over a wide range of temperatures for tough materials.
A Simple Method for Measuring Tearing Energy of Nicked Rubber Strips
Authors: Oh HL
Published: March 2009

A convenient test configuration for measuring critical tearing energy of rubber is to pull thin nicked strips of the rubber in extension. In the past, methods of measurements employed for this configuration are based on concepts which obtain “tearing energy” through differentiation with respect to the crack length. As a consequence, measurements have to be made on several identical specimens having different crack lengths. This paper describes a simple method based on the J-integral which requires no differentiation and calculates the tearing energy from measurements made on one specimen only. This allows an efficient use of test material and reduces the complexity of critical tearing energy measurement.

Implementation of the J-integral method is illustrated on the uniaxial stretching of a nicked rubber strip. The accuracy of results obtained is found to be comparable to that obtained by existing methods.
A Study of Plane Stress Fracture in the Large-Scale Plastic Yielding Regime
Authors: Tardiff GE , Kuhn BA , Heldt LA
Published: March 2009

Three independent methods for measuring plane stress fracture resistance in the large-scale plastic yielding regime were tested and were found to give equivalent results. The three methods were the J-integral technique, a method based on the increase in compliance that accompanies the development of a plastic zone, and a method based on the direct measurement of the plastic work that must be done to cause fracture.
A Fracture Mechanics Approach to Creep Crack Growth
Authors: Landes JD , Begley JA
Published: March 2009

A fracture mechanics approach was used to study high-temperature creep crack propagation. Crack growth rates were correlated with the C*-parameter which is an energy rate line integral. For materials conforming to a nonlinear stress and strain rate relationship in the steady-state creep range, specifically, those which can be properly idealized as purely viscous (negligible elastic and transient creep effects), C* characterizes the crack tip stress and strain rate fields.

Crack growth rate tests were conducted in the creep range on a discaloy superalloy at 1200°F (920 K). Two specimen geometries were tested, a center cracked panel and a compact geometry, to establish the geometry independence of this approach. The results showed that crack growth rate correlated with the C*-integral, while other parameters (K and nominal stress) failed to adequately characterize crack growth rate.
What R-Curves Can Tell Us About Specimen Size Effects in the KIc Test
Authors: Lake RL
Published: March 2009

Size effects in the KIc test were investigated by testing duplicate compact specimens in ten different combinations of five thicknesses and five widths. Curves of crack resistance as a function of crack extension were calculated in terms of strain energy release rate, G, rather than stress intensity factor, K. It was found that the entire set of data could be represented by a single linear equation of the form, R = Ro + ρΔa. The coefficient, ρ, was found to be an inverse function of specimen thickness.

When this family of R-curves is compared with the driving force, G, curves for the various specimen sizes, it can be seen that the ratio of maximum load to the measuring point load (Pmax/PQ) in the record of a plane strain toughness test, depends primarily on the width/thickness ratio of the specimen. This ratio appears to bear no relation to the contribution of crack tip plasticity to the apparent crack extension at the measuring point. Accordingly, inclusion of a maximum value of this ratio in the validity requirements of ASTM Method E 399 for the purpose of restricting such a contribution is questioned.
Effect of Stress Ratio and Overload Ratio on Fatigue Crack Delay and Arrest Behavior Due to Single Peak Overloads
Authors: Himmelein MK , Hillberry BM
Published: March 2009

In this investigation stress interaction effects on fatigue crack propagation following single peak overloads in 2024-T3 aluminum alloy were studied. The two parameters investigated were the overload stress ratio, ROL=Kmin/KOL, and the overload ratio, KOL/Kmax. Tests were run with quasi-constant stress intensity fatigue loading following the overload. The effect of overload on the crack growth rate through the overload plastic zone was observed. Additional tests were run to determine only whether or not crack arrest would occur. The delay effect due to single peak overloads was found to increase with overload stress ratio, ROL, and overload ratio, KOL/Kmax. The higher values of both ROL and KOL/Kmax produced nonpropagating fatigue cracks, and the delay/arrest boundary was defined.
Predicting Fatigue Crack Retardation Following a Single Overload Using a Modified Wheeler Model
Authors: Gray TD , Gallagher JP
Published: March 2009

A modification to the Wheeler fatigue crack retardation model is proposed. The modification allows the model to be used without reliance on data fitting and, therefore, without the subsequent limiting to a specific material or to a specific set of loading parameters. The new model is used to predict existing data for the number of delay cycles following a single overload in 2024-T3 aluminum, 4340 steel, and Ti-6A1-4V titanium alloy. All predictions were within essentially a factor of two of the experimental data.
Residual Life Estimates for Structures with Partial Thickness Cracks
Authors: Besuner PM
Published: March 2009

This paper presents a practical approach for estimating residual fatigue life of structures with partial thickness cracks under arbitrary Mode I cyclic elastic stress fields. Residual life is defined herein as the number of cycles required to grow the crack from specified initial dimensions to some final configuration that results in static failure. A powerful influence function theory is modified for application to three-dimensional stress analysis of planar crack problems with arbitrary crack front shapes. The resulting procedure allows stress intensity factor solutions and residual fatigue life estimates for any Mode I stress field applied to the crack geometry.

Exact stress intensity factor solutions are presented for the buried ellipse under arbitrary Mode I stress fields. A procedure is outlined to build useful, accurate stress intensity factor algorithms for complex surface crack geometries from a few three-dimensional numerical stress analyses.
Establishing Steady-State Thermal Conditions in Flat Slab Specimens
Authors: Shirtliffe CJ
Published: March 2009

The thermal response of flat slab specimens subjected to four sets of thermal boundary conditions is examined. The conditions are typical of thermophysical test apparatus, and the four sets of conditions are similar. Initial temperatures are uniform and the cold face temperature is stepped to the required value. There are four different hot face conditions: (1) constant temperature, (2) constant heat flow, (3) zero heat flow followed by constant temperature, and (4) zero heat flow followed by constant heat flow.

Solutions are given for the heat transfer problems, and the equations are truncated, then inverted, to yield simple, approximate expressions for response time. The precision of the approximate equations is shown to be adequate for prediction purposes; the four sets of conditions are ranked in order of increasing response time; and the occurrence of optimum situations is noted.
Mechanisms of Heat Transfer in Permeable Insulation and Their Investigation in a Special Guarded Hot Plate
Authors: Bankvall CG
Published: March 2009

This paper presents the use of a specially designed guarded hot plate apparatus in analyzing and predicting the heat transfer behavior of a permeable insulating material. It is shown how the mechanisms of heat transfer in a fibrous material can be interpreted from simple physical models and measurements in the guarded hot plate. It is also shown that with the appropriate theoretical background and calculations, the natural convective heat transfer in a permeable material may be studied on a small scale and then used in the investigation of the heat transfer in full-scale structures.
Radiative Contribution to the Thermal Conductivity of Fibrous Insulations
Authors: Linford RMF , Schmitt RJ , Hughes TA
Published: March 2009

Design studies on the reuseable surface insulation (RSI) systems for the Space Shuttle require accurate data on the thermal conductivity of ceramic-fiber insulations. Well-established laboratory techniques, such as the guarded hot plate experiment, are available for such measurements; however, caution must be exercised in applying laboratory data to widely different re-entry thermal environments. The heat-transfer associated with infrared radiation transmitted through the fibrous materials must be considered. Various analytical models have been developed to account for this radiant heat transfer, but their verification has often been incomplete. A new approach has now been applied in which infrared transmission measurements were made with an optical system that collected all the scattered radiation transmitted through the back surface of fibrous samples. Experimental data were analyzed using a “two-flux” model for the radiation scattered and absorbed in the materials and excellent correlation was obtained between theory and experiment. To account for the wavelength dependence of the scattering cross-sections of many materials, a “four-flux” model was developed. This model was used to compute the contribution of the radiation transmission to the total thermal conductivity of samples measured on the guarded hot plate equipment. The contribution was shown to be as high as 75 percent of the total conductivity at temperatures above 1000 K.

The significance of this result is that data obtained from such instruments should not be used in heat-transfer design computations without regard to the radiation transmission. Such regard will be particularly important in the thermostructural analyses of RSI for the Space Shuttle and other re-entry vehicles.
Analysis and Measurement of the Heat Transmission of Multi-Component Insulation Panels for Thermal Protection of Cryogenic Liquid Storage Vessels
Authors: Bourne JG , Tye RP
Published: March 2009

A new concept involving the use of easily fabricated and assembled panels consisting of balsa wood, rigid plastic foams, and wood facings has been proposed for the external thermal protection of large liquid natural gas storage vessels.

Heat transmission determinations in scale models of the proposed panels up to 90-mm thick have been undertaken with the use of a 600-mm square guarded hot plate apparatus for the proposed use temperature conditions. In addition, thermal conductance measurements on the basic components have been made at regular temperature intervals over the approximate range 100 to 300 K.

An analytical model has been derived to predict the variation in test results with geometry. This model can be used to select the optimum full scale configuration considering both thermal and structural performance and to predict tank heat leakage.
Three-Dimensional Solution for a Through-Thickness Crack in a Cross-Plied Laminate
Authors: Wang SS , Mandell JF , McGarry FJ
Published: March 2009

A three-dimensional solution is given to the problem of a through-thickness edge crack in a thin 90/0/0/90 laminate under uniform tension normal to the crack direction. The solution is obtained from a three-dimensional finite-element analysis based on the hybrid stress model, and formulated through the Hellinger-Reissner variational principle. The results indicate that the classical 1/√r stress singularity is maintained for the in-plane stresses which vary through the thickness and are discontinuous at the ply interface. The interlaminar shear and normal stresses also increase rapidly as the crack tip is approached; the interlaminar shear stresses are always maximum at the ply interface, while the interlaminar normal stress may be maximum at the interface or at the laminate center. The in-plane stresses follow a similar distribution and give an average through-thickness stress-intensity factor similar to two-dimensional predictions. The interlaminar stresses show a strong interaction of the crack tip singular and free-edge effects, as well as a strong influence of the degree of biaxiality of the in-plane stresses. The results suggest several aspects of subsequent subcritical crack extension.
Uniaxial Failure of Composite Laminates Containing Stress Concentrations
Authors: Nuismer RJ , Whitney JM
Published: March 2009

Two previously developed failure criteria for predicting the uniaxial tensile strength of a laminated composite containing through-the-thickness material discontinuities (notches) are subjected to further experimental scrutinization. In particular, the two-parameter (unnotched tensile strength of the laminate and a characteristic length) models, which are capable of predicting observed discontinuity size effects without resorting to the concepts of linear elastic fracture mechanics, are based on limited experimental verification.

In the present paper, and experimental program is presented which examines the effect of changes in the material system, the laminate fiber orientations, and the notch shape and size (stress gradient), on the model predictions. This is accomplished by obtaining experimental data on two material systems, glass/epoxy and graphite/epoxy, in conjunction with two orientations of fiber-dominated laminates containing through-the-thickness circular holes and sharp tipped cracks of several sizes.

In addition to the test results, two observations based on the models are presented. First, the statistical failure distribution for a composite containing a circular hole is predicted using the models and shown to agree well with experimental observations. Second, an Irwin type correction factor applied to the stress intensity factor is shown to result in nearly constant values of the critical stress intensity factor for all values of crack length. The correction factor is shown to be related to the characteristic length of the present models.
Fracture of Composite Compact Tension Specimens
Authors: Slepetz JM , Carlson L
Published: March 2009

Fracture experiments were carried out on compact tension specimens of unidirectional and cross-ply S-glass/epoxy and graphite/epoxy. Fracture toughness values were determined by the compliance calibration technique and by measuring the area under the load-displacement curve. In unidirectional specimens, crack extension was always parallel to the fibers and was dependent on crack length. Toughness did not vary significantly with fiber orientation relative to the load direction in unidirectional S-glass/epoxy. Tests on cross-ply S-glass specimens were not valid because crack propagation did not occur; instead, a zone containing a system of superficial parallel cracks and other damage developed, which extended with increasing load. Cross-ply graphite specimens, on the other hand, did appear to give valid test results although the cracks propagated were not always straight and other damage mechanisms were also present. Toughness values for cross-ply graphite were approximately two orders of magnitude higher than for unidirectional specimens due chiefly to the fracture resistance of fibers transverse to the crack. Toughness values determined by the compliance calibration method were consistent with reported values obtained by other methods.
Fracture Mechanics Correlation of Boron/Aluminum Coupons Containing Stress Risers
Authors: Adsit NR , Waszczak JP
Published: March 2009

The mechanical behavior of boron/aluminum near stress risers has been studied and reported. This effort was directed toward defining the tensile behavior of both unidirectional and (0/ ±45) boron/aluminum using linear elastic fracture mechanics (LEFM). The material used was 5.6-mil boron in 6061 aluminum, consolidated using conventional diffusion bonding techniques.

Mechanical properties are reported for both unidirectional and (0/ ±45) boron/aluminum, which serve as control data for the fracture mechanics predictions. Three different flawed specimen types were studied. Tension coupons containing circular centerholes, double edge notches, and center notches as well as control specimens were tested. The circular hole and double edge notched specimens were tested with various flaw sizes. In each case the series of specimens remained geometrically similar to eliminate variations in finite size correction factors. The center notched specimens were used to obtain conditions more in line with conventional plane-strain fracture testing.

The fracture data from these tests were reduced using two techniques. They both used conventional LEFM methods, but the existence of a characteristic flaw was assumed in one case and not the other. Both the data and the physical behavior of the specimens support the characteristic flaw hypothesis. Cracks were observed growing slowly in the (0/ ±45) laminates, until a critical crack length was reached at which time catastropic failure occurred.
Concepts for Crack Arrestment in Composites
Authors: Sendeckyj GP
Published: March 2009

Crack arrestment criteria for composite panels containing buffer (or crack-arrestment) strips are derived for the cases of cracks within the primary and buffer-strip material. The criteria, which can be used to size the buffer strips to arrest cracks of given length, are in good agreement with the available experimental data on crack arrest in composite panels.
Some Relationships Between the Viscometric Properties of Motor Oils and Performance in European Engines
Authors: Bell JC , Voisey MA
Published: March 2009

Piston ring wear, bearing wear and fuel consumption have been measured in European engines run under fully warmed-up conditions at steady speed and load. The engines were lubricated with motor oils which were formulated from a range of types and concentrations of VI improvers and base oil blends. The viscosities, viscosity/temperature relationships and viscosity/shear-rate characteristics of these formulations varied widely. The results for all the oils tested showed a poor correlation with their low shear-rate viscosities measured at 210°F or 150°C but a good correlation with their viscosities measured at shear rates of 105 to 106 sec−1.
Measurement of the Viscosity of Multigrade Oils in a Running Engine
Authors: Lane G , Roberts DC , Tims JM
Published: March 2009

Conventional laboratory viscometric methods are not adequate to characterise the behaviour of multigrade oils in service, in that they take no account of the high shear rates occurring in running engines. A technique has been developed which permits the measurement of apparent viscosity in the crankshaft bearings of engines running under road conditions. The technique is to isolate a single bearing, provide it with its own oil feed and calibrate flow-rates through it under normal running conditions using single grade oils. Flow rates obtained with multigrade oils can then be converted to apparent viscosities, seen by the bearing under operating conditions.

Results show that temporary viscosity loss due to shear is important even at moderate speeds (3000 rpm) in normal production engines. Shear breakdown characteristics of a range of different chemical types of VI Improvers have been compared. The technique has also been modified to permit determination of the minimum viscosity acceptable to the engine by relating this parameter to temperature increases in the bearings.
Time Dependance of Polymer Oils Shear Thinning Theoretical and Practical Consequences
Authors: du Parquet JPR
Published: March 2009

Theoretical analysis supported by specially designed experiments show that the viscosity loss of polymer thickened oils is basically a time dependant phenomenon. Depending on the value of the residence time of the oil in the contact and on the critical degradation time corresponding to the shear severity, it is possible to describe the case of EHD contacts such as gears and HD contacts such as plain bearings.

The results have theoretical and practical consequences. In particular the viscosity in EHD contacts could be much lower than usually supposed. A better understanding of mechanical shear is expected from the proposed approach.
Current Concepts of Indicator Bacteria
Authors: Yehuda K
Published: March 2009

Pathogenic bacteria excreted in human feces are found in low counts in wastewater and are known to be more sensitive to environmental conditions than Escherichia coli. The latter, excreted both by humans and warm-blooded animals, are used as an indicator of fecal wastes which may contain the pathogen, but the validity of this practice is often questioned. In wells recharged with chlorinated lake water, regrowth of coliform bacteria reached 105/100 ml when the water was re-pumped 7 to 28 days later. Very often, the more sensitive E. coli die away and are replaced by other coliforms, so that counts do not in themselves indicate a change in water quality.

Recently, low numbers of Samonella have been detected with the aid of large sampling procedures. On the other hand, there has been little additional data on the efficiency of wastewater treatment plants. Survival varied from 0.003 up to 29 percent in a recent study. S. typhimurium survived in a sand column up to 44 days, while S. typhi did not last more than seven days. Shigella flexneri, introduced into an experimental oxidation pond, were recovered from the effluent but were killed by application of 8 mg/1 chlorine after a short contact time.

The possibility of using coliphage as a means for identifying E. coli has been considered in an additional investigation. Coliphage are found in wastewater effluents in counts ranging from 104 to 105/100 ml. They are quite durable under adverse conditions and have been found to be highly resistant to chlorination. Enterovirus densities in wastewater vary between 100 and 2000/100 ml. Comparative studies have indicated that coliphage are found whenever enteroviruses are, and their ratio may vary from 1000 to one to as low as ten to one. It is believed that this recent technique employing indicator microorganisms will permit more rapid and precise evaluations of water quality and potential health hazards.
Microbiological Monitoring—A New Test for Fecal Contamination
Authors: Leclerc H , Mossel DA , Trinel PA , Gavini F
Published: March 2009

Bacteriological monitoring of drinking water has not changed essentially during the last decennium. Escherichia coli and fecal coliforms are still traditionally used as index organisms, although methods are slightly different in various countries.

Investigations carried out by the authors have demonstrated that conventional methods can still be criticized in two respects. The spontaneous dying off of the Salmonella in water often occurs at a considerably lower rate than that of E. coli, which can lead to falsely negative results. In addition, investigations on human enteric flora composition, using newer methodology, have demonstrated that coli-aerogenes bacteria other than E. coli occur in relatively high concentrations. Two approaches will allow the elimination of these deficiencies of conventional monitoring of drinking water. They are using the entire group of Enterobacteriaceae as index organisms or considerably increasing the sensitivity of testing for E. coli.

For the latter purpose, an instrumental, continuous method has been developed. Water samples are first passed through a hollow fiber ultrafiltration device. Thereupon enrichment is carried out by culturing in lactose broth at 41°C. After stripping off the carbon dioxide (CO2) formed by fermentation, the liquid is mixed with a glutamate solution buffered at pH 3.9, the CO2 formed set is freed by acidification, and then absorbed in a phenolphtalein buffer which is ultimately examined colorometrically. The sensitivity of this method is 1 colony forming unit (cfu) of E. coli/100 ml or better. It has the additional advantage of allowing much more representative sampling of a water supply than customarily carried out.
Potential Health Hazards Associated With Pseudomonas aeruginosa in Water
Authors: Hoadley AW
Published: March 2009

Pseudomonas aeruginosa is an opportunistic pathogen of man and animals which may be spread by water. The major source of P. aeruginosa in waters appears to be fecal wastes of man and animals associated with man, although growth may occur under certain conditions. The demonstration of the species in surface waters suggests the influence of man, and its numbers reflect the degree of pollution. However, they survive only for short periods, and there frequently appears to be little relation between populations of P. aeruginosa and those of other pathogens or fecal indicators.

The value of P. aeruginosa as an indicator of potential health hazards associated with water must be judged on the basis of its own role as a waterborne pathogen. In this paper, the role of P. aeruginosa as a waterborne pathogen, its sources, and its behavior in aquatic environments are reviewed. Its isolation from drinking waters, farm water supplies, swimming pool waters, whirlpool waters, and surface recreational waters should be regarded with concern. However, while authorities have recommended limitations on P. aeruginosa in waters used for various purposes, few epidemiologic studies have been undertaken upon which to base standards, and few standards have been established.
Bifidobacteria as Water Quality Indicators
Authors: Levin MA
Published: March 2009

The potential value of bifidobacteria as indicators of fecal pollution in water has not been fully explored. Nevertheless, a number of workers have suggested that bifidobacteria may be useful as indicator Organisms because (a) they do not multiply in nature, (b) they exhibit survival characteristics which compare favorably to Escherichia coli, and (c) they may be useful as specific indicator organisms to differentiate animal from human fecal pollution.

An identification scheme for the most common species and which may be applicable in determining the type of pollution has been developed, and current techniques of speciation and quantitation are discussed.
Candida albicans
Authors: Buck JD
Published: March 2009

This paper presents current knowledge regarding the potential of the human pathogenic yeast Candida albicans to serve as an indicator of health hazards associated with the use of natural waters. In lieu of defined procedures for the specific detection of the organism from natural habitats, the discussion emphasizes what is known concerning distribution of the yeast in nature and possible sources for subsequent occurrence in water. The necessity is stressed for the development of selective media to allow comparative quantitative and qualitative assessment of yeast densities, particularly in recreation waters.
South African Experience on Indicator Bacteria, Pseudomonas aeruginosa, and R+ Coliforms in Water Quality Control
Authors: Grabow WOK
Published: March 2009

Drinking waters obtained from conventional sources and reclaimed wastewater in South Africa have been analyzed for standard bacterial plate count, total coliform bacteria, fecal coliforms, confirmed Escherichia coli, type I, Pseudomonas aeruginosa, fecal streptococci, Clostridium perfringens, Staphylococcus aureus, enteric viruses, and parasite ova. Apart from the standard plate count, waters which were free of coliforms rarely contained any of the other organisms. P. aeruginosa occasionally was isolated from waters with a zero coliform count, and it is suggested that this organism should be included in some routine quality tests. Epidemiological studies on an isolated community, which included periods when drinking water obtained by conventional methods was supplemented with supplies reclaimed from wastewater, indicated that water which conforms to the criteria of nil coliforms and P. aeruginosa/100 ml, a standard plate count of less than 100/1 ml, and no detectable enteric viruses/10 litre will not transmit microbial diseases. Hospital and city sewage, as well as a river and reservoir polluted with secondary treated sewage, contained large numbers of coliforms with transferable (R factor) resistance to one or more of five commonly used antimicrobial drugs. The survival of R+ coliforms and the transfer of resistance during treatment of sewage and in polluted waters indicated that advanced treatment of wastewater will be necessary to protect water resources against these organisms which have potential health significance. It is suggested that specifications limiting R+ bacteria should be included in water quality standards.
Bacterial Indicators of Water Quality in Swimming Pools and Their Role
Authors: Mood EW
Published: March 2009

The most significant bacterial indicator of the quality of swimming pool water is the total 35°C agar plate count. Specific bacterial indexes such as Escherichia coli have been used by various agencies, but these indexes are less sensitive than the total 35°C agar plate count. Also, there is no concensus of opinion as to what constitutes acceptable values for these specific indexes. Properly designed, constructed, and operated swimming pools with an adequate level of residual disinfectant can be maintained with total plate counts which are less than 100 colonies/ 1.0 ml. The bacterial quality of swimming pool water is usually a measure of the adequacy of the disinfecting process. Microbiological examination of samples of swimming pool water for specific genus or species are needed usually only in conjunction with a suspected outbreak of disease among the users of a swimming pool.
Isolation of Yersinia enterocolitica From Water
Authors: Highsmith AK , Feeley JC , Morris GK
Published: March 2009

Only in the last few years has Yersinia enterocolitica been recognized as an etiologic agent. An increasing awareness of this organism is evidenced by the number of recorded cases and isolations each year from a variety of sources throughout the world. Previous failure to isolate Y. enterocolitica may be related to lack of familiarity rather than absence of the organism. Presence in the animate and inanimate environments does provide opportunity for transmission by person to person, animals, foodstuffs, and water, but vehicles of disease transmission are not fully delineated. General hygienic techniques in regard to food and water sanitation should apply in the methods for controlling the disease caused by Y. enterocolitica. The bacteriology of Y. enterocolitica is reviewed and laboratory methodology is described.
Klebsiella
Authors: Vlassoff LT
Published: March 2009

Klebsiella pneumoniae is well distributed in the environment and found to be associated primarily with wastes high in organic matter and human activity.

K. pneumoniae is a serious opportunistic pathogen of increasing concern in hospitals, where precolonization seems to be a prerequisite to infection. Epidemiological data are lacking to link infection with high K. pneumoniae concentrations in the environment. Presently, it cannot be enumerated reliably by primary plating methods.

The presence of K. pneumoniae in water indicates degraded quality, and it is probably as significant as finding Escherichia coli and a good indicator of pollution from certain organic wastes.
Variations in the Evaluation of ASTM A 262, Practice E, Results (ASTM Subcommittee A01.14 Round Robin)
Authors: Walker WL
Published: March 2009

A total of 42 evaluations in accordance with ASTM Recommended Practices for Detecting Susceptibility to Intergranular Attack in Stainless Steels (A 262-75), Practice E, were obtained from seven different organizations on the same eleven sensitized Type 304 stainless steel specimens subjected to different exposure times in boiling acidified copper-copper sulfate solution and then bent on a 1-T radius. The results indicate that subjective factors influence such evaluations, as evidenced by differences in the classification of the same specimens between different evaluators, with one specimen classified as “passed” and “failed” by approximately equal percentages of evaluators.
Effect of Moisture on Epoxy Resins and Composites
Authors: Delasi R , Whiteside JB
Published: March 2009

The effect of absorbed moisture on the properties of six neat epoxy resins (3501-5, 3501-6, 3502, 5208, 934, and NMD 2373) and three epoxy composites (AS/3501-5, B/5505, and hybrid B/5505-AS/3501-5) is explored. Excellent agreement among the diffusion coefficients, activation energy, and activation entropy is observed for all resins with the exception of NMD 2373. Good correlation exists between neat resins and corresponding composites. The effect of a weekly thermal cycle on the diffusivity and equilibrium moisture content of two resins and three composites is presented. Correlations are developed between preconditioning temperature and relative humidity on the magnitude of the anomalous moisture absorption.

In addition, the effect of absorbed water on the glass transition temperature of six neat epoxy resins and two composites using thermomechanical analysis is considered. The water generally behaves as a classical plasticizer of the epoxy resin, lowering the glass transition temperature as predicted from theory. Comparison between neat 3501-5 resin and AS/3501-5 reveals generally good correlation in Tg at comparable resin moisture levels, but plasticized hybrid boron-graphite/epoxy laminate exhibits a somewhat lower Tg than predicted from theory.
Diffusion of Water Vapor in Graphite/Epoxy Composites
Authors: Shirrell CD
Published: March 2009

T300/5208 graphite-fiber-reinforced epoxy laminates were exposed to 33 different combinations of temperature and relative humidity. The diffusivities and equilibrium solubility for both nonpostcured and postcured laminates were determined at 21, 43, and 63°C (70, 110, and 145°F). Non-Fickian absorption anomalies were observed at five different relative humidities and water immersion for specimens at 82°C (180°F). Moisture diffusion was examined with respect to possible ply thickness, stress, and moisture concentration effects.