bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation of Insulating Properties of Closed-Cell Foam Insulation
Authors: Ostrogorsky AG , Glicksman LR 
Published: March 2009

Heat is transferred through closed-cell foam insulation by conduction through the solid polymer making up the cell structure, conduction through the low conductivity gas (blowing agent) inside the cells, and radiation. The effective thermal conductivity of closed-cell foam panels changes with the foam age due to diffusion of air components into the foam and diffusion of the blowing agent out from the foam. The change in the composition and thermal conductivity of the gas mixture was modeled as a function of the aging time. The change in the composition is computed by solving the transient diffusion equations for each gas species in the foam. The thermal conductivity of the gas mixture is computed from an empirical correlation proposed by Lindsay and Bromley.
A computer program was developed to numerically solve the governing equations. The effective diffusion coefficients of the air components and the blowing agent are the main code inputs. The numerical prediction of the change of the effective conductivity of foam panels for a given age is within 6% or better of the conductivity obtained in long-term tests under three different thermal environments.
Foam Insulation Aging: Historical Perspective and Outstanding Problems
Authors: Zwolinski LM 
Published: March 2009

Rigid polyurethane foam originated in the World War II era. This material, the reaction product of polyisocyanates and hydroxyl-terminated polyols, was originally expanded by in situ generation of carbon dioxide during the polyurethane polymerization process. A major improvement in the insulation value of polyurethane foam was effected in the early 1950s by the development of technology to use chlorofluorocarbons (CFCs) as the blowing agent.
This paper presents a historical perspective on the development of rigid polyurethane foam as a superior insulation material. The role of CFC expansion agent will be examined with a review of the early concerns of aging of foam and the accompanying change in insulating property. The effects of blowing agent diffusion, humidity during foam aging, and the aging environment gas on the thermal conductivity of cellular material are detailed. Early attempts to explain heat transfer through rigid cellular structures in terms of conduction, convection and radiation factors are cited.
Attention is focused on problems outstanding to a complete understanding of foam aging. These factors include test methodology, the role of gas diffusion, polymer distribution in a cellular structure, effects of barrier materials, in-service moisture influences, foam structure features, and total insulation-containing structural design.
Long-Term R-Values and Thermal Testing Requirements for Rigid Insulating Foams
Authors: Hagan JR , Miller RG 
Published: March 2009

This paper presents the results of two experimental studies. The first was a continuation of a 5-year aging study on foil-faced polyisocyanurate thermal insulation boards. These boards were retested in the guarded hot box and represent 11-year aged data. The results indicated excellent agreement with the plateaued R-values established on the 5-year aged samples.
The second effort is an ongoing correlation study between the large-scale guarded hot box and small-scale heat flow meter tests using permeable faced polyisocyanurate foam thermal insulation boards. Thicknesses tested ranged from 2.5 to 8.1 cm (1 to 3.2 in.). The results to date show that, in general, with proper sampling of large-scale boards, good agreement can be expected between guarded hot box and heat flow meter test results.
A Survey of Window U-Value Measurements in Sweden (1977–1987)
Authors: Staelens P 
Published: March 2009

At the Swedish National Testing Institute (SP) window thermal transmittance (U-value) measurements are carried out in a Guarded Hot Box (GHB). It is shown that the GHB meets the requirements of the relevant Swedish Standard (SS 024212,13) and International Standard Draft Proposal (ISO/DP 8990). The SS 024213 measurement routines are discussed.
A survey of measurement results acquired during the last ten years shows the continuous improvement of the U-value of windows produced in Sweden as well as the increasing importance of additional panes and improved sealed glazing units.
By way of comparative Guarded Hot Plate (GHP) and GHB measurements on sealed glazing units it is shown that the GHP method should be examined thoroughly and its results handled with care in order to prevent misinterpretation by, for instance, the client. It is further noted that the GHB technique, although commonly used, is not completely investigated and that on the level of standardization much work is yet unfinished.
Heat Transfer Characteristics of a Recently Developed Lightweight Structural Concrete
Authors: Van Geem MG 
Published: March 2009

A lightweight structural concrete was developed for use in exterior walls of low-rise residential and commercial buildings. The lightweight concrete has a unit weight of 800 kg/m3 (50 pcf), a compressive strength of 13.8 MPa (2000 psi), and a thermal conductivity of 0.23 W/m · K (1.6 Btu · in./h · ft2 · °F). Lightweight concretes have not been previously developed with this combination of low density and moderate strength. The most commonly used concrete, normal weight concrete, has a unit weight of approximately 2320 kg/m3 (145 pcf), a compressive strength in the range of 17 to 41 MPa (2500 to 6000 psi), and a thermal conductivity of 1.7 to 2.3 W/m · K (12 to 16 Btu · in./h · ft2 · °F).
The portland cement concrete developed for this project can be used to combine structural, thermal insulation, and heat storage capacity functions of exterior walls in one element. For many climates this concrete can be used without additional insulation as a complete wall system in lowrise buildings.
Heat transfer characteristics of two 200-mm (8-in.)-thick, full-size wall assemblies were evaluated using a calibrated hot box (ASTM C 976). One test specimen, designated Wall L, was a 200mm (8-in.)-thick wall constructed entirely of the newly developed lightweight structural concrete. The second specimen, designated Wall S, was the same as the first except for a 150-mm (6-in.)-high normal weight concrete strip running horizontally across the wall at midheight. The horizontal strip simulates a floor slab extending through an exterior wall.
Overall thermal resistances of Walls L and S, respectively, are 0.92 and 0.83 m2 · K/W (5.2 and 4.7 h · ft2 · °F/Btu) at 24°C (75°F). Thermal resistance of Wall S is 11% less than that for Wall L.
Tests under dynamic temperature conditions provide a measure of thermal response for selected temperature ranges. Dynamic response includes heat storage capacity as well as heat transmission characteristics of the wall assembly. Results from a 24-h period, sol-air temperature cycle showed that heat storage capacity of the low density concrete delayed heat flow through the test specimen. Average thermal lag for the 200-mm (8-in.)-thick lightweight concrete wall was 6 h.
Thermal and physical properties of the lightweight concrete were also measured on small-scale specimens. Concrete thermal conductivity, thermal diffusivity, specific heat, compressive strength, flexural strength, splitting tensile strength, shear strength, modulus of elasticity, drying shrinkage, and freeze/thaw resistance were determined.
Laboratory test results provide information on the thermal and physical performance of the new lightweight concrete.
Computer Modeling of Climates
Authors: Cash CG 
Published: March 2009

The mathematical study of many dynamic responses of building materials and constructions to climatic variations has been hampered by the lack of a suitable way to model climatic components such as temperature, precipitation, humidity, wind, solar radiation, and cloud cover. It was noticed by the author that a curve called the “companion to the cycloid” seems to be similar in shape to ambient temperature versus time plots. This was the start of the work reported in this paper because, if a successful model of the temperature cycles could be developed, we would have a powerful tool to help us in our understanding of the thermal behavior of materials and systems.
This paper presents methods for the mathematical modeling of the ambient air temperature at any location where statistical atmospheric data are available. The model was checked by comparing the calculated air temperatures with the actual air temperature data at six diverse locations in the continental United States. In addition, the actual hourly air temperatures (recorded at three-hour intervals) were compared with the calculated hourly air temperatures from the model for a six-year period at one location.
The model was expanded, with data from the literature, to model the temperature of white, gray, and black roof surfaces. These calculated surface temperatures are used to illustrate the utility of the model in estimating the sliding potential of several bituminous roofs.
The usefulness of the minimum temperature and the temperature loading parts of the model has been demonstrated by the work reported in this paper. The validity of the surface temperature part of the work is yet to be established.
Finding the proper curve shape for the thermal model opens up many lines of investigation for studying building materials as dynamic components. Other studies currently being performed include the migration of bitumen through the felts within the roofing membrane and the displacement of one-ply systems in response to the normal thermal cycles. Future studies are not limited to roofing; the model can be applied wherever the effects of temperature cycles are important.
The preliminary look at the sliding potential of bituminous built-up roofing membranes reported in this paper may be the start of a study to provide rational limits for the maximum slope that should be permitted for each class of bitumen, instead of using timeworn standards that may not be appropriate.
Factors Influencing Consumer Insulation Activities
Authors: Meeks CB 
Published: March 2009

Using a sample of 37 687 single family homeowners from the 1980 Annual Housing Survey, this study applied discriminant analysis to determine which variables influence presence, addition, and cost of insulation. Housing units with insulation were more likely to have storm doors or windows, be newer, more expensive, be located in the Northcentral region rather than the South, and have an attached fan and electric or oil heat rather than natural gas. An increase in the age of the head and presence of a child under 6 years old as well as length of occupancy were more highly associated with housing without insulation.
The addition of insulation was more likely in older homes, homes located in regions other than the South, homes heated with oil, liquid petroleum gas, or wood rather than natural gas, and homes with storm doors or windows and an attached fan. While presence of a child under 6 years old increased the probability, length of occupancy had a negative impact.
Using these variables as discrimators, 74.2% of the households with insulation were correctly classified, while 60.5% of the households who added insulation were correctly classified. Expenditures on insulation varied with region, length of occupancy, age and value of the house, and presence of an attached fan. Thus this study provides a base for identifying households which will undertake insulation activities.
Review of ASTM Guide for Removable Insulation Covers (C 1094)
Authors: Hart G 
Published: March 2009

With a need for periodic inspection or access to many hot insulated surfaces, removable/reuseable insulation covers have been found to be a good solution. These covers reduce the heat loss on surfaces such as valves, flanges, pumps, compressors, and piping where otherwise a permanent, non-reuseable type of insulation might be added. The use of removable covers can reduce the long-term cost of gaining access to the hot surfaces that need periodic inspection.
There are a number of different performance requirements encountered by removable insulation covers on hot surfaces. In general, the covers should insulate effectively, be capable of being easily removed and replaced, and last a certain period of time. An impediment to their durability is the conditions to which the blankets are exposed: high service temperature, leaking chemicals, sun and rain, physical abuse, and fire, among others. The selection of appropriate materials to meet the performance requirements of a particular job can be a difficult and complex task. Such a selection is generally addressed with specifications.
As as first step in developing removable insulation specifications, ASTM Committee C-16 on Thermal Insulation formed a task group to develop a standard guide. This document, which was balloted before Committee C-16 in late 1987 and received Society approval as ASTM C 1094 in 1988, identifies the performance issues faced by removable covers and their constituent materials. Being a guide, it does not recommend particular materials or even performance values. Rather, it recommends appropriate test methods, as well as general design and construction issues, that should be addressed by a specification. The use of ASTM C 1094 in developing removable cover specifications should ultimately improve the performance and quality of those covers.
The Introduction of a Skidding-Resistance Policy in Great Britain
Authors: Gargett T 
Published: March 2009

Research associated with skidding resistance has been ongoing at the Transport and Road Research Laboratory (TRRL) for over 50 years, and in 1979 a draft “Standard” based on that research was prepared by the Department of Transport for implementation on the National trunk road network. However, the Standard was not issued because not enough was known about the existing levels of skidding resistance, and with the information then available it was not possible to demonstrate the cost-effectiveness of introducing the policy.
In an effort to provide the necessary information, the Department planned a National Skidding Resistance Survey (NSRS) based on the Sideway-force Coefficient Routine Investigation Machine (SCRIM), and during 1982 survey was undertaken on a short (approximately 10-km lengths) sample basis to represent the network nationwide and to provide an adequate number of samples of the many different categories of site that are encountered on a road system. Altogether a representative sample of about 1000 km was taken forward for further analysis. The sample was broken down into short subsections and each allocated to a site category such as traffic light approach, nonevent open road, motorway, bend, major junction, minor junction, dual carriageway, and single carriageway. Average and minimum skidding-resistance values were determined for each subsection and all injury accidents, each defined by type (dry no-skid, dry skid, wet no-skid, wet skid), were allocated to the subsection of their occurrence.
Analysis of the data demonstrated that very different skidding resistance/accident relationships existed between the various categories of site. Based on the findings, a policy was developed that would not only save accidents but also could be shown to be highly cost-effective. The paper briefly summarizes the findings of the NSRS and outlines the general principles (including skidding resistance values) of new skidding-resistance policy for in-service roads.
Predicting the Skid Resistance of Bituminous Pavements Through Accelerated Laboratory Testing of Aggregates
Authors: Diringer KT , Barros RT 
Published: March 2009

The goal of this study was to correlate the results of a laboratory test procedure measuring aggregate polish resistance with skid resistance in bituminous pavements. This correlation would be instrumental in identifying skid-resistant aggregates and would create the potential for assuring lifelong-skid-resistant bituminous pavements.
This study was conducted in two phases. The first estimated the empirical relationship between aggregate microtexture and cumulative polishing using a modification of the ASTM standards: Recommended Practice for Accelerated Polishing of Aggregates Using the British Wheel (D 3319-83) and Standard Method for Measuring Surface Frictional Properties Using the British Pendulum Tester (E 303-83). An exponential model was developed which realistically approximates the minimum polish value observed with the theoretical asymptote of the polishing rate curve. The magnitude of this asymptote, PV, correlated well with New Jersey's skid-resistance experience with specific aggregate types and was subsequently used in the study's second phase.
In the second phase of this study, a more detailed relationship between PV and long-term minimum skid resistance was sought. Experiments were conducted to evaluate polish values of aggregates and skid resistance of bituminous pavements composed of these aggregates and to collect environmental data on selected skid test sites over a period of one year. This information was used to normalize the skid resistance of a bituminous pavement in terms of the aggregate's polish value and cyclical environmental factors.
Because further refinement is needed, a tentative acceptance limit for aggregate prequalification may be identified using this relationship. Possible values for this acceptance limit may range from PV = 25 to PV = 32, depending upon the factors one chooses to include in this consideration.
Additional research is required to check and refine the models developed. This paper concludes with a detailed description of the work to be accomplished in order to finalize this analysis and implement a statistical specification for the prequalification of surface course aggregates based on polish resistance.
Evaluating the Polishing Properties of Aggregates and Bituminous Pavement Surfaces by Means of the Penn State Reciprocating Polishing Machine
Authors: Nitta N , Saito K , Isozaki S 
Published: March 2009

In this study, the polishing properties of coarse aggregates and bituminous pavement mixtures were investigated by means of the Penn State Reciprocating Polishing Machine. The test results were evaluated by BPN5000, which is the measured British Pendulum Number (BPN) after 5000 polishing passes of a rubber pad using alumina (35 μm) abrasive. Aggregate mineral hardness was measured by the Shore Hardness Testing Machine.
Polishing tests for eleven aggregate samples were performed and the results were compared with the results of Shore hardness tests. The results suggested that an average of Shore hardness and its coefficient of variation (CV) are both significant factors for evaluating the polish susceptibility of coarse aggregate. Based on these results, polishing rate, τ, defined as a measure of polish susceptibility, was successively related with the above two factors in the multiple linear regression form which can be used to predict polish susceptibility of coarse aggregate in the laboratory.
Another series of polishing tests was performed to determine the effects of asphalt binder components and the coarse aggregates on the polishing properties of bituminous mixtures. The results suggested that the most important factor affecting polishing levels of a mixture is the exposed area of aggregate in the specimen surface. An attempt was made to relate BPN5000 of various mix designs with an exposure ratio, Er, defined as a measure of exposed area of aggregate, in the linear relation that can be used to estimate the polishing level of bituminous mix designs in the laboratory by measuring only Er.
Dynamic Behavior of a Vehicle on a Rutted Road
Authors: Nakatsuji T , Kaku T , Fujiwara T , Hagiwara T , Onodera Y 
Published: March 2009

Wheel ruts on paved roads affect the maneuverability of a vehicle and sometimes trigger fatal accidents. At present, however, not enough is known about the cause of this unstable maneuverability on a rutted road. It is the purpose of this paper to provide some information on the dynamic behavior of a vehicle running on a rutted road. In order to evaluate the stability and controllability of a vehicle on a rutted road, we performed various running tests both on a rutted road and on a flat road.
Based on analyses using root-mean-squared (rms) values and the Developing Spectrum, the following conclusions were obtained: (1) RMS values for the vehicular motion on a rutted road are much greater than those on a flat road; (2) low-frequency contents below 1 Hz play an important role in the behavior of the vehicle on a rutted road; (3) visual guidance by ruts occasionally leads to stable straight runnings on a rutted road; and (4) the severer the lane-changing conditions, the larger the interaction between sprung mass and unsprung masses.
Surface-Smoothness Evaluation and Specifications for Flexible Pavements
Authors: Uddin W , Hudson WR , Elkins G 
Published: March 2009

The quality of smoothness of a newly constructed or overlaid pavement dictates the beginning of pavement management. Adequate acceptance testing procedures and specifications for pavement smoothness have not been available for flexible pavements. Smoothness specifications based on a 10-ft (3.05 m) straightedge has a number of limitations and is difficult to interpret and administer. This paper describes the results of a comprehensive study of several different roughness measuring devices undertaken to select a suitable device in order to develop and implement improved specifications for pavement smoothness. The candidate devices included the 690D Profilometer, Model 8300 Roughness Surveyor, Maysmeter, California Profilograph, and Rainhart Profilograph.
In this study, the 690D Profilometer ranked highest in overall performance. The paper describes the benefits and negative aspects of each type of equipment related to its use for surface-smoothness measurement and acceptance testing of newly constructed pavements and pavement overlays. The results are useful for any agency desiring to improve its smoothness measurement and acceptance testing procedures.
The Noss Roughness Meter: A Norwegian Road-Roughness Measurement System
Authors: Noss PM 
Published: March 2009

The development of a new Norwegian device for the measurement of road roughness started in 1985. A prototype is now finished. Tests demonstrate that longitudinal profiles of wheeltracks measured with this equipment meet the requirements to qualify as “Class 1: Precision profiles” [1], which represent the highest standard of accuracy for measurements of the International Roughness Index (IRI).
The longitudinal profile is given as elevation points with 25-cm spacing along the measured wheeltrack, and different criteria for road roughness can be computed from this profile. In February 1988, necessary software was completed to compute IRI as described by The World Bank [1]. In addition, computed straight-edge values can be presented as histogram for any section length chosen by the operator.
The measurements are independent of traveling speed, and the calibration of the equipment is very simple. The production of the first series of the equipment will start in 1988, and it will be used both for detailed studies on test sections and for road network surveys in Norway.