bluuebunny/crossref_metadata_2025 huggingface dataset:
The Breuer-Beckhard Precast Facades
Authors: Beckhard H
Published: March 2009

The author traces the discovery and use of precast concrete in his work in partnership with Marcel Breuer, one of the foremost figures of 20th century architecture, and later, in his own practice.

From the first use at La Gaude, France, for an IBM research center, to a recent high-rise office building in Jersey City, New Jersey, precast concrete for facade treatment has proven economical, free of the vagaries of field labor, quickly installed, of great durability, and easy to maintain.

But what is of great interest to the author is the multitude of visual variations of precast. Citing examples, he shows how his aesthetic sense responds to the material's flexibility: in form, use of color, texture, and techniques to expose the aggregate. He demonstrates his technical response to the material, its use in its load-bearing capacity, and as a building skin. Illustrations show how the sculptural elements of the architecture are a direct response to the technical possibilities of the material.

In closing, the author states that, based on all its qualities, precast concrete “is truly a material of our time.”
A Method for Evaluating the High Strain Rate Compressive Properties of Composite Materials
Authors: Montiel DM , Williams CJ
Published: March 2009

A test apparatus and method developed to obtain high strain rate compressive mechanical properties of various fiber-reinforced composite materials is described. This direct compressive method uses a drop tower to impart a load at dynamic rates to the test fixture. Uniform specimen loading is accomplished through the use of aligned guiderails to constrain all but the vertical motion of a free-sliding impactor. Specimen endcaps, specific to thick-section testing, are implemented to prevent premature brooming failure. A piezoelectric transducer and aluminum absorbers are some of the refinements introduced to allow acquisition of stress and strain data free of distortion. Strain rates on the order of 8 s-1 have been achieved, and higher rates appear possible. Material property data were obtained on a series of AS4 graphite/PEEK thermoplastic [02/90]8s composite laminates. The results of this first study indicate that at high strain rate loading, the strength of this material increases 42% over static values, while the strain to failure increases by 257#x0025;. There also appears to be a small effect of increased strain rate on the initial and secant moduli for this material.
Characterization of IM7 Graphite/Thermoplastic Polyetheretherketone (PEEK) for Spacecraft Structural Applications
Authors: Silverman EM , Wiacek CR , Griese RA
Published: March 2009

Graphite composites fabricated from thermoplastic polyetheretherketone (PEEK) IM7 graphite prepreg tapes were evaluated for the development of lightweight, strength-critical, dimensional stable spacecraft components. The objective of this investigation was to summarize the mechanical and physical properties of IM7 graphite/PEEK to compare its properties to that of similar graphite/epoxy composites.

A property database for thermoplastic composite materials was generated. Composite mechanical property characterization included 0° and 90° tensile and compressive, in-plane shear, and flexural properties. Physical property characterization included coefficient of thermal expansion, outgassing/condensable volatiles, and equilibrium moisture absorption at 71°C (160°F) and 95% relative humidity. Scanning electron microscopy (SEM) was used to investigate fiber/matrix distribution, fiber orientation, and fiber/resin interface adhesion. Results were compared with data on IM7 graphite/8551-7 epoxy laminates to assess the relative merits of the IM7 graphite/PEEK thermoplastic material system.

In general, IM7 graphite/PEEK thermoplastic composites possess a combination of properties that appear to match the requirements for several spacecraft applications. In addition to having very respectable structural properties, IM7/PEEK laminates exhibited lower moisture uptake and lower outgassing than IM7/8551-7 epoxy laminates. The equilibrium moisture gain for the thermoplastic composites was 0 18% compared to 0 80% for the epoxy composite system. SEM analysis indicated that the thermoplastic PEEK composite laminates exhibited excellent fiber/matrix distribution and interfacial fiber/resin adhesion. The PEEK thermoplastic matrix composite, therefore, provides a superior replacement to conventional epoxy matrix composites for spacecraft applications.
Characterization of Unnotched SCS-6/Ti-15-3 Metal Matrix Composites at 650°C
Authors: Pollock WD , Johnson WS
Published: March 2009

TI-15-3 reinforced with SCS-6 silicon carbide fibers, in five different lay-ups, was tested at 650°C to determine monotonic and fatigue strengths, basic mechanical properties, and damage initiation and progression. The elevated temperature results were compared to those obtained at room temperature. Analytical predictions were made of the monotonic stress-strain response as well as cyclic stress-strain hysteresis. The fiber reinforcement was found to increase significantly the static and fatigue strengths of the laminates over those of the matrix material at elevated temperature; the increase was insignificant at room temperature. Initial damage, in either the fibers or the matrix, was partitioned as a function of the life and applied strain range in the constituents. High strains and short lives resulted in multiple fiber failure with no signs of matrix fatigue cracking. Low strains and long lives resulted in extensive matrix cracking and no fiber breaks away from the fracture surface. At 650°C, the matrix was too weak to cause fiber-matrix interface failure before matrix yielding. Laminate fatigue lives were hypothesized to be a function of the 0° fiber stress. More scatter was found in the 0° fiber stress versus high temperature fatigue life data than in the room temperature data. An initial unloading modulus that was greater than the initial loading modulus was observed in the elevated temperature fatigue tests.
A Macro—Micromechanics Analysis of a Notched Metal Matrix Composite
Authors: Bigelow CA , Naik RA
Published: March 2009

A macro-micromechanics analysis was formulated to determine the matrix and fiber behavior near the notch tip in a center-notched metal matrix composite. Results are presented for a boron/aluminum monolayer. The macro-level (or global) analysis models the entire notched specimen using a three-dimensional finite element program that uses the vanishing-fiber-diameter model to model the elastic-plastic behavior of the matrix and the elastic behavior of the fiber. The micro-behavior is analyzed using a discrete fiber-matrix (DFM) model containing one fiber and the surrounding matrix. The dimensions of the DFM model were determined by the ply thickness and the fiber volume fraction and corresponded to the size of the notch-tip element in the macro-level analysis. The boundary conditions applied to the DFM model were determined from the macro-level analysis. Stress components within the DFM model were calculated, and stress distributions are presented along selected planes and surfaces within the DFM model, including the fiber-matrix interface. Yielding in the matrix was examined at the notch tip in both the macro- and micro-level analyses. The DFM model predicted higher stresses (24%) in the fiber than predicted by the global analysis. In the notch-tip element, the interface stresses indicated that a multi-axial stress criterion may be required to predict interfacial failure. The DFM analysis predicted yielding to initiate in the notch-tip element at a stress level 28% lower than predicted by the global analysis.
Composite Material Stub-Blade Wing Joint
Authors: Franklin WM , Kreimendahl BW
Published: March 2009

A design study to determine the viability of a stub-blade wing joint for HALE (high-altitude, long-endurance) aircraft is presented. The resulting wing joint design uses advanced composite materials and is capable of carrying moderately high bending, shear, and torsional loads. The stub-blade concept is similar to the wing joint design used on sailplanes and is particularly applicable to a large-span, high-aspect-ratio, unswept wing that uses a single-cell wing box to carry spanwise loads. This wing structure and geometry are typical of many HALE aircraft. The stub-blade joint can be located at any wing station and uses “pin-in-a-socket” action to transfer loads from the outboard to inboard wing box. Justification and criteria for material selection are presented. Extensive use of graphite/epoxy, co-cured and bonded structure is made to achieve a minimum weight design. Major design drivers include minimum weight, ease of fabrication, and ease of repeated assembly and disassembly of the joint. The latter would be desirable on a large-span aircraft for which hangar or transportation limitations would require repeated removal of outer wing sections. A FORTRAN program was developed to optimize the blade length based on weight, and a NASA Structural Analysis (NASTRAN) model of the stubblade design was constructed to investigate the distribution of internal loads. The stub-blade joint presented in this paper was sized to loads generated for a representative baseline HALE vehicle. This Lockheed Baseline HALE Aircraft is an unmanned vehicle capable of reaching an altitude of 27 432 m (90 000 ft) and features a 8163-kg (18 000-lbs) gross weight and 80.5-m (264-ft) wingspan. The stub-blade wing joint design is weight competitive with the traditional tensiontype wing joint and offers attractive features such as ease of assembly and disassembly, ease of fabrication, and aerodynamic smoothness.
An Evaluation of the Current Status of Automated Process Control for Thermosetting Composites
Authors: Holl MW , Rehfield LW
Published: March 2009

Automated process control for thermosetting composite cure is used to ensure part quality while reducing the energy required to manufacture parts. This study summarizes the techniques used in automated process control and evaluates the progress toward implementing these methods in production. An ideal transducer must provide information about the physical state of the resin while the part is in the processing tool. It must also be able to survive the hostile environment of processing equipment, be simple to install, not interfere with the mechanical properties if it is left behind in the part, and, of course, be economical. Promising transducers based on dielectric, acoustic, and fluorescent signals are detailed in this study. When the physical state is known, the control algorithm acts on the information to vary the cure parameters (temperature, pressure). A number of different strategies for controlling the cure have been proposed. All are developed by trial and error and are part-specific. As more is understood about the physical mechanisms of resins during processing, algorithm development will be easier.
Free-Edge Stress Analysis of Glass-Epoxy Laminates with Matrix Cracks
Authors: Fish JC , O'Brien TK
Published: March 2009

An experimental and analytical study was conducted on the influence of matrix cracking on delamination in (+ 15/90n/-15)s glass-epoxy laminates subjected to monotonically increasing tension loads. Four different layups are examined with the number of symmetric 90° layers varying from 0 to 3 (n = 0, 1, 2, 3). Experimental results show that local delaminations form at the intersection of matrix cracks in the + 15° plies and the free edge. A quasi-three-dimensional (Q3D) finite-element analysis is used to examine free-edge stresses in undamaged laminates. Q3D results show that: (1) in-plane transverse tensile stresses exist in the +15° plies near the free edges of all of the laminates and (2) only the interlaminar shear stress is high at the + 15/θ interface. Three-dimensional (3D) finite-element analyses are used to model a + 15° ply crack near the laminate free edge. The 3D analysis results indicate that large tensile interlaminar normal, as well as shear, stresses develop at the intersection of the matrix crack and the free edge. This suggests that the interlaminar normal stress plays a significant role in the failure of these laminates and emphasizes the importance of modeling matrix cracking in delamination analyses of composite structures.
Efficient Use of Film Adhesive Interlayers to Suppress Delamination
Authors: Lagace PA , Bhat NV
Published: March 2009

An experimental and analytical study was conducted to assess the effectiveness of the efficient use of film adhesive interlayers in suppressing delamination in composite laminates. Efficiency was achieved by two means: (1) the adhesive interlayer was placed only at delamination critical interfaces, identified by calculating the interlaminar stresses and applying the Quadratic Delamination Criterion, in comparison to all ply interfaces as in previous investigations and (2) finite-width strips were used rather than full-width film adhesive layers. Graphite/epoxy [± 157/07]s laminates, with FM300 Interleaf material placed at the + 15/-15 interface, were tested in uniaxial tension. For all specimens with film adhesive interlayers, the load at which delaminations initiated was about 50% higher than in the case of the specimens without film adhesive. The final failure stresses of the specimens with film adhesive also averaged 40% higher than those without the interlayers. These results were not discernably affected by the use of a reduced number of interlayers and, furthermore, did not depend upon the width of the strip. This indicates that, within practical manufacturing limitations, any strip which is as large as the interlaminar stress boundary layer would be successful in inhibiting delamination initiation. However, in tests which Teflon® strips were inserted to simulate preinitiated delamination, the results were similar to those in which no film adhesive interlayers were present. This indicates that the interlayers are not successful in suppressing the growth of delamination which is already present. Experimental results also suggest the possible existence of a “critical” delamination initiation size.
Damage Tolerance of Three-Dimensional Commingled PEEK/Carbon Composites
Authors: Hua CT , Chu J-N , Ko FK
Published: March 2009

The concept of structural toughening of composites by three-dimensional (3-D) fiber architecture is demonstrated. Polyetherketone (PEEK) matrix in filament form was commingled with carbon fiber before preform fabrication and composite consolidation to facilitate matrix introduction into the 3-D fiber network. The effect of matrix viscosity was found to be essential for effective fiber wetting in the 3-D fiber network. The tolerance of 3-D composites to damage induced by open holes and by impact was investigated under tensile and compressive loading. 3-D reinforced composites were found to have higher compression after impact strength and an order of magnitude lower damage area under 13 J/mm impact energy in comparison to laminated PEEK/carbon composites. This high level of damage tolerance is due to the lack of delamination inherent to 3-D reinforced composites.
Advances in Thermographic Stress Analysis and Evaluation of Damage in Composites
Authors: Zhang D , Sandor BI
Published: March 2009

Development of the thermographic stress analysis (TSA) method and the stress pattern analysis by thermal emission (SPATE) method for stress analysis and evaluation of damage in fiber-reinforced composites during the past five years is reviewed, and some new results are presented. The fundamental factors affecting the TSA signals, calibration methods, stress analysis, stress (strain) separation, and methods of qualitative and quantitative evaluation of damage are discussed. Reasonable future research topics are outlined.
Novel Adjuvants for Agrochemical Formulations Based on Sugar Ethers
Authors: Hoorne D , Chasin DG , Rogiers LM
Published: March 2009

The adjuvant can influence the performance of the herbicide. The use of sugar ether based adjuvants in greenhouse trials in combination with two sugar beet herbicides Betanal Compact (*) (Phenmedipham - Desmedipham EC) and Goltix WG (*) (Metamitron WG) resulted in a superior weed control when compared to the use of the active on its own.

Field trials of sugar ether based adjuvants together with a commercial fungicide formulation like Sportak (*) (Prochloraz EC), Sandofan M8 (*) (Oxadixyl - Mancozeb WP), Impact (*) (Flutriafol SC) and Matador (*) (Tebuconazole - Triadimenal EC) against Septoria Apii indicated an increase in the performance of the formulation. With certain fungicides the combination of the sugar ether blends with a crop oil concentrate, like ‘Atplus’ 411 F, imparted an increased activity to the formulation compared to when both adjuvants were used separately.

All the test indicate that the sugar ether blends can be seen as the replacement for the traditionally used alkylarylalcohol-type adjuvants.
Physical Properties of Silicone Surfactants for Agrochemical Applications
Authors: Murphy DS , Policello GA , Goddard ED , Stevens PJG
Published: March 2009

Aqueous solutions of four silicone surfactants, and two hydrocarbon surfactants were studied over a range of concentrations for dynamic surface tension lowering, spreading on paraffin wax film, and static surface tension. Dynamic surface tension profiles were obtained by both the oscillating jet method and the maximum bubble pressure method. It was found that aqueous solutions of the silicone surfactants lower surface tension more quickly, spread better on paraffin wax film, and yielded lower static surface tension values than corresponding aqueous solutions of the hydrocarbon surfactants. Implications of the findings as regards effectiveness of these adjuvants are discussed.
Preparation and Evaluation of Concentrated Emulsions of Agrichemicals
Authors: Friloux KM , Tann RS
Published: March 2009

A model concentrated emulsion was chosen for this study. The methods of preparation and evaluation are discussed. Recommendations are made concerning the formulation of concentrated emulsions and appropriate test methods for their evaluation are presented.

Several processing steps and ingredients were required to produce the model formulation. Each of these ingredients' role in the system will be described. The techniques used in the production of CEs are included.

The formulations were evaluated by a variety of methods. These methods included: Heat Stability, Freeze/Thaw Stability, Particle Size, and Viscometry. Each was studied to predict the shelf life of the formulation. The use of any or all of the methods presented can significantly reduce the evaluation time required for these formulations.
Controlling Microbial Growth in Aqueous-Based Pesticide Formulations
Authors: Haack TK , Warwick EF
Published: March 2009

Flowable pesticides contain dispersants and thickeners that can support the growth of microorganisms. Even limited microbial growth in a flowable pesticide can destroy the integrity and performance of the product. Biocides are typically added to flowables to prevent microbial growth. Because an exemption from tolerance is required for any biocide added to a formulation, the list of products available to the formulator is extremely limited. The newest biocide chemistry to receive EPA exemption from tolerance for pesticide preservation is methylchloroisothiazolone (MCI). The efficacy of MCI in pesticide products was determined with microbial challenge tests. Results indicated that MCI kills microorganisms as effectively as formaldehyde, but at significantly lower concentrations. MCI is compatible with other inerts, non-phytotoxic (even at 50 times use level), and biodegradable. It is also stable and effective over a wide range of pH. Stability and efficacy tests have indicated that flowable pesticides that are aggressive to 1,2 benzisothiazolin-3- one can be effectively preserved with MCI biocide.
Colloidal Microcrystalline Cellulose as a Thickener in Flowables
Authors: Ibrahim NI , Mehra DK
Published: March 2009

The proper selection of a thickener in the process of formulating pesticide flowables is crucial. The following factors are important to consider: 엯 Long term shelf stability 엯 Ease of container rinsing (or facilitating the rinsability of containers) 엯 High percent of active loading 엯 Facilitate production by rapidity of hydration and dispersion 엯 Batch-to-batch consistency in viscosity and high yield stress values 엯 Freeze thaw stability 엯 Compatibility with wide range of materials 엯 Effectiveness over a broad pH range (4–10).

Lattice™ NTC colloidal microcrystalline cellulose from the Food and Pharmaceutical Products Division (FPPD) of FMC combines thixotropic and plastic properties thus providing excellent utility as a thickener. Dynamic rheological measurements comparing Lattice NTC, Xanthan gum and VeegumR are discussed.
Using Nonionic Surfactants in Aqueous Formulations
Authors: Utz CG , Drewno GW , Hollis RP
Published: March 2009

Water-based formulations for liquid actives are relatively new to the agricultural market. Surfactant combinations have been identified which provide long-term stability and good dilution characteristics in concentrated emulsions (oil-in-water emulsions [EW]) and suspoemulsions (combinations of a liquid and solid active in a water-based formulation). For EW formulations, surfactant combinations consist of two nonionic EO/PO block copolymers. One has relatively hydrophobic character containing little EO and acts as emulsifier, while a relatively hydrophilic component with a large EO content facilitates dispersion in water. Suspoemulsions are stabilized by adding block copolymers containing 30 to 50% EO to commercial flowables. Some formulations require additional polyacrylate polymer as dispersant. These stable formulations are made without any thickeners or other stabilizers.

EW formulations have been demonstrated with pyrethroids and 2,4-dichlorophenoxyacetic acid. Combinations of malathion/carbaryl and metolachlor/atrazine have been successfully formulated in suspoemulsions. The physical stability and dilution characteristics of the formulations are described.
A Photometric Study of Dilute Microcapsule Suspensions
Authors: Stern AJ
Published: March 2009

Dilute suspensibility of solids, of great importance to the users of suspension concentrate formulations, is a complex subject. In order to better understand the behavior of dilute microcapsule suspensions, a photometric method has been used to quantitatively measure their sedimentation as a function of time. Applied to eight different microcapsule formulations, this method has shown that 1) microcapsule settling rates are not linear; 2) shell wall structure largely influences the degree of microcapsule flocculation and hence settling rates; and 3) in many cases, suspension and resuspension are inversely related.
The Delivery of Agricultural Fungicides in Paucilamellar Amphiphile Vesicles
Authors: Tabibi SE , Sakura JD , Mathur R , Wallach DFH , Schulteis DT , Ostrom JK
Published: March 2009

A novel water-borne formulation of 2-(thiocyanomethylthio) benzothiazole (TCMTB) has been produced using paucilamellar amphiphile vesicles. The vesicles were made from dimethylamides of tall oil fatty acids (DMATO). Greenhouse testing on cotton seeds and seedlings showed that this water-borne formulation was as effective in protecting cotton seeds and seedlings against fungal pathogens as commercially available formulations containing organic solvents and/or surfactants.
Cold Temperature Properties of Pesticides Dissolved in Aromatic Hydrocarbon Fluids
Authors: King EJ , Verbelen RA
Published: March 2009

A study was conducted to evaluate the cold temperature behavior of various pesticide solutions as the chemical composition of the solvents varied. Solutions of seven pesticides in solvents containing primarily: (1) C9 and (2) C10 alkylbenzene and (3) C11–12 alkylnaphthalene, were prepared and observed for precipitation between ambient and -10 °C in 5 °C steps. Of the aromatic hydrocarbon fluids tested those containing C11–12 alkylnaphthalene compounds were the best solvents for the pesticide active ingredients tested. Removal of naphthalene from the C10 alkylbenzene and C11–12 alkylnaphthalene fluids did not adversely affect the solvency of the resultant pesticide solutions.
An Unexpected Interaction Between Inerts Used in Solvent Based Formulations
Authors: Dean SW , Dexter RW
Published: March 2009

In the course of an investigation on a formulation, it was found that under certain conditions two inert ingredients (calcium dodecylbenzene sulfonate (CaDDBS) and triethylene glycol (TEG) combined to form a crystalline precipitate. This novel complex of CaDDBS and TEG occurs only in non-aqueous systems; the presence of small amounts of water prevents its formation. The effects of temperature, chemical structure of the CaDDBS, water content and alcohol content are addressed.
Some Practical Limitations of Fluorescent Tracers Used to Measure Off-Target Pesticide Deposition.
Authors: Hall FR , Kirchner LM , Downer RA
Published: March 2009

Eight tracers were chosen for the study, based on availability, cost, previous work done in this laboratory, and extent of use by other researchers. Laboratory photodegradation was determined for each of the tracers over 0 – 100 minutes under ‘light’ and ‘dark’ conditions. Storage degradation was measured on a modified set of tracers over a period of 41–45 days under ‘frozen’, ‘light lab’, and ‘dark lab’ conditions. Both studies used a Turner 112 fluorimeter.

The photodegradation data suggest that Uvitex EC would be unsuitable for use in any drift trial situation since the fluorescence decreased up to 82 % under light conditions and nearly 16 % under dark conditions. The other tracers generally showed some decreases but not nearly as marked. Storage degradation data showed that the fluorescence of Tinopal CBS-X decreased by as much as 67 % under light lab conditions. The other tracers showed some reductions but not as marked as Tinopal CBS-X.

The results are considered in terms of their practical implications in relation to protocol development for off-target pesticide deposit (drift) studies.
Atomization and Application of Biopesticide Formulations
Authors: Steinke WE , Akesson NB
Published: March 2009

Biopesticide materials are increasingly used in forestry, agriculture and vector control. Their low mammalian toxicity and low environmental hazard potential has encouraged researchers and applicators to evaluate their control potential for a variety of insect pests. However, the resulting formulations of these materials, primarily Bacillius thuringiensis (Bt) and baculoviruses, have not been easy to use under field conditions. Additionally, their physical properties and equipment for applying them did not meet the desired drop size of 80 to 100 micrometers vmd (or Dv.5)that biologists thought were most desirable.

Formulation and drop size studies have been initiated to determine the most suitable atomizers, rotary and hydraulic, to use with the various formulations being developed. Physical properties of these formulations indicate the usual reduction in surface tension to about 50% that of water, which tends to reduce the drop size produced compared with that of water. Density does not appear to be a factor of concern, but viscosity, particularly of the virus formulations, may be over 100 mPa∙s and may cause flow problems in spray equipment or produce a large drop size resulting in poor distribution and reduced control. Several formulations were tested along with various atomizers and data on these are shown.
Aerial Spray Deposits of

Bacillus Thuringiensis

in Experimental Trials Over Hardwood Forests
Authors: Sundaram A
Published: March 2009

Dipel® 8AF was sprayed aerially over an oak forest (Study I, conducted in Ontario, Canada, in 1987) undiluted at 30 BIU in 1.8 L/ha on block B1 and diluted at 30 BIU in 6.2L/ha on block B2. Spray drops were collected on cylindrical Kromekote® cards, and deposit was determined on aluminum oak leaves by fluorometry for the tracer dye added to the tank mixes. The data showed that the drop sizes on samplers were markedly smaller in block B1 than those in B2. The deposits (expressed in IU/cm2) at canopy and ground levels were correspondingly lower in B1 than in B2.

Foray® 48B was sprayed aerially over an oak forest (Study II, conducted in Pennsylvania, USA, in 1990) undiluted at 50 BIU in 3.94 L/ha on block B3 and at 75 BIU in 5.91 L/ha on block B4. Drop spectra were assessed on water-sensitive paper, and deposits were determined on glass micro-fiber filters by a bioassay method using gypsymoth. The observed mortalities were converted into IU of deposit/cm2 area of the filters. The data indicated that drop sizes on samplers were only slightly smaller in block B3 than those in B4. The deposits were also not markedly different.

When converted into IU/cm2 per BIU sprayed, the deposits were: Study I Ground level: B1, 1.3 IU/BIU-cm2; B2, 3.0 IU/BlU-cm2 Canopy level: B1, 1.5 IU/BIU-cm2; B2, 3.7 IU/BIU-cm2 Study II Ground level: B3, 1.7 IU/BIU-cm2; B4, 0.68 IU/BIU-cm2 Canopy level: B3, 1.3 IU/BIU-cm2 ; B4, 0.75 IU/BIU-cm2

The conclusion was that the differences in deposits in the two studies were not as enormous as might be expected, considering the fact that the studies were conducted under different field conditions, and using different dosages, volume rates, samplers and quantification techniques for deposit assessment.
The Benefits of an Anti-Evaporant in Pesticide Applications
Authors: Thacker JRM , Hall FR
Published: March 2009

In this paper we report the results of a series of laboratory experiments that were designed to quantify the effects of adding an anti-evaporant to a permethrin formulation. Assessments were made of the effects of the anti-evaporant upon: droplet evaporation rates, droplet retention and bounce, droplet spread, and the implications of these parameters for an improved biological efficacy.

Evaporation rates were assessed using a 2m high, temperature controlled, droplet settling tower. A monosize droplet generator was used to produce the droplets which were measured at their entry and exit from the tower using water sensitive papers. The difference in droplet size was then used to calculate the mean droplet evaporation rate for each of the temperature levels (25°C -50°C) used.

Droplet retention or bounce was determined by exposing the angled, adaxial leaf surfaces of greenhouse cabbage and chrysanthemum plants, to a range of spray droplet sizes, in a spray chamber. The spray chamber was constructed so that vertically falling droplets would either be retained by the leaf or would bounce onto adjacent water sensitive papers. The difference between the number of droplets that were sprayed upon the leaf and the number that bounced was used to provide an index of droplet retention for a range of leaf angles and droplet sizes.

The spread of droplets was quantified by using fluorometric analysis to visualize the droplets following their application to the adaxial surface of cabbage leaves. A range of droplet sizes and insecticide concentrations were used. The implications for improved biological efficacy were assessed by preliminary testing against 2nd instar cabbage looper, Trichoplusia ni (Hübner).

The results of these and other experiments are discussed in terms of the advantages and disadvantages to be obtained from the use of an anti-evaporant in pesticide applications.
A Summary of the Manufacture, Uses, and Properties of Autoclaved Aerated Concrete
Authors: Mathey RG , Rossiter WJ
Published: March 2009

This report is a review of the properties and performance of autoclaved aerated concrete. The material has a relatively low thermal conductivity combined with load-bearing capacity for use in structural and non-structural applications. This feature may make its use attractive for energy-conserving applications.

The review addressed an overview of the manufacturing process, uses of autoclaved aerated concrete in building constructions, properties, energy considerations, the availability of code-related documents, and standards. Uses include block and panel construction in load-bearing and non-load-bearing applications for walls, floors, and roofs. Many properties are reviewed including density, fire resistance, moisture expansion and shrinkage, strength, structure, and thermal conductivity. With regard to energy considerations, the review points out that, for energy-efficient applications under severe climatic conditions, the autoclaved aerated concrete unit alone may be insufficient to provide the targeted minimum value of thermal resistance. In these cases, autoclaved aerated concrete has to be used together with additional thermal insulation. In contrast, autoclaved aerated concrete alone may satisfy insulation needs in areas having mild climates.
Magnesium Oxychloride-Based Foam Thermal Insulation: An Initial Investigation
Authors: Rossiter WJ , Brown PW
Published: March 2009

This study is an initial investigation of the properties and performance of magnesium oxychloride-based foam thermal insulation. Tests and observations were performed on samples prepared in the laboratory and also removed from one cavity of a wall of a wood-frame house. The tests to characterize the foam included measurements of density, moisture content, shrink age, and thermal conductivity, and were combined with analysis using X-ray diffraction, scanning electron microscopy, and thermogravimetry techniques.

It was found that the foam had a thermal conductivity comparable to that of other insulations used to retrofit walls of houses. Shrinkage could not be quantified, but was seen to be generally small. The moisture content of the foam removed from the house was about 2%. The results of the analytical measurements indicated that the laboratory-prepared samples and some of those removed from the house were not identical. It was suggested that further analysis be conducted to continue characterization of the foam.
Solid Conductivity of Loaded Fibrous Insulations
Authors: Fricke J , Büttner D , Caps R , Gross J , Nilsson O
Published: March 2009

The thermal conductivity and the elasto-mechanical behavior of a fibrous glass paper insulation and of a fibrous alumina fleece were investigated as a function of external pressure load. The main findings are: (1) at an external load Pext = 1 bar the solid thermal conductivity λs of the glass fiber paper is about 1.5 ∙ 10-3 W/(m ∙ K) and for the fleece is 3 ∙ 10-3 W/(m ∙ K); and (2) the variation of λs with Pext is weak for the paper and pronounced for the fleece.

Three models were employed to study the correlation between λs and the elasto-mechanical behavior: Kaganer's model, percolation theory, and the phonon diffusion model.
Overview of Physical Properties of Cellular Thermal Insulations
Authors: Strzepek WR
Published: March 2009

A comprehensive overview of the physical properties of cellular thermal insulations commonly used in the insulation industry has been developed. The insulations addressed are molded, expanded polystyrene (MEPS) and extruded, expanded polystyrene (XEPS) foams, polyurethane (PUR) and polyisocyanurate (PIR) foams, urea-formaldehyde (U-F) foams, phenolic foams, and cellular glass. Information was compiled primarily from manufacturers' literature, published documents, and private communications.

In addition to a general listing of typical physical properties, three areas are given special emphasis. The effects of aging and mean temperature on thermal transmission properties are discussed. Moisture absorption values measured using several different methods are presented, and a tabulation of typical mechanical strength properties is included.

The information presented is intended to serve as a general guide for comparing the physical properties of the various cellular insulations commonly used. The values are intended to be conservative; however, this may not be true for some commercially available products. Therefore it is recommended that the insulation manufacturer be contacted to obtain values for use in design.
Measurement of Gas Diffusion in Closed-Cell Foams
Authors: Shankland IR
Published: March 2009

The aging process in closed-cell thermal insulation foams refers to that phenomenon which results in a degradation of insulation value of the foam over a period of time and is generally attributed to diffusion of atmospheric components into the foam and diffusion of expansion agent out of the foam. In this paper an apparatus is described for measuring the effective or apparent diffusion coefficient of atmospheric and other rapidly permeating gases in closed-cell polymeric foams. The technique is based on a solution of the transient diffusion equation, which is outlined along with the method of data reduction. The diffusion cell is designed to accommodate cylindrical foam specimens of varying sizes up to 7.6 cm (3 in.) in diameter and up to 5.1 cm (2 in.) thick. Other features of the apparatus include quick and convenient interchange of foam samples as well as automatic data acquisition. Major sources of experimental error are discussed; those aspects of the experimental technique designed to reduce the magnitude of the experimental uncertainty are also mentioned.

Results obtained with the apparatus for a number of different foams are presented and discussed in terms of various foam diffusion models described in the literature. Interpretation of the data in this manner gives some insight into the cellular structure of the foam and also provides a correlation for estimating the diffusion coefficient of other gases in the foam sample.
An In Situ Evaluation of the Settling of Loose-Fill Rock Wool Insulation in the Attics of Two Manufactured Home Units
Authors: Graves RS , Yarbrough DW
Published: March 2009

The effect of vibrations due to manufacturing and transport on the thickness, density, and calculated thermal resistance (R-value) of loose-fill rock wool insulation installed in two manufactured home units has been determined. Thickness and density measurements on blown attic insulation were made after installation, at the end of the manufacturing process, and after the units were towed 426.5 km (265 miles). These measurements were used to calculate R-values for the attic insulation. The end sections of the two units showed an overall insulation thickness decrease of about 16% and an average R-value change from 5.50 to 5.08 K · m2/W (31.2 to 28.8 ft2 · h · °F/Btu). An estimated R-value greater than 5.29 K · m2/W (30 ft2 · h · °F/Btu) resulted from averaging the end and middle sections of the two units. The effect of reduced thickness along the edges of the attic space was not included in the estimate.
New Developments Toward Accurate Assessment of Material Density for ASTM C 687 Testing of Pneumatically Applied Insulations
Authors: Mathis RC , Kenney TM
Published: March 2009

Quality measurements of the thermal performance of pneumatically applied mineral fiber insulations by use of a heat flow meter device require accurate assessment of the density of material in the specific area of the heat flow meter. Current standard methods to determine this density are inadequate. A compression sampling device/technique has been developed which increases the accuracy and repeatability of density determination. Operator judgement is also greatly reduced. This device, coupled with more detailed and standardized thermal specimen generation techniques, promotes reduced density variation within the test specimen. A ±5% density variation is achievable.
A Round Robin on Apparent Thermal Conductivity of Several Loose-Fill Insulations
Authors: Adams RD , Hust JG
Published: March 2009

The primary means of establishing the thermal performance of loose-fill insulation is ASTM Standard Practice C 687. To provide information for the development of a statement of precision and bias for this Standard Practice, a round robin was carried out by eleven laboratories measuring apparent thermal conductivity of four common loose-fill insulation products (cellulose, rock/slag wool, and bonded and unbonded glass fiber) and a glass fiber blanket.

The test results on the glass fiber blanket indicate that the measurement capability of the participants can be characterized by an imprecision of 3.0%, as measured by two standard deviations, and a negligible bias of the mean. The measurements on the loose-fill materials are characterized by an imprecision ranging from 21% for cellulose to 10% for the rock/slag wool. The increase in imprecision for the loose-fill materials is attributed primarily to inadequately defined procedures for preparing and conditioning the specimens.
A Theoretical and Experimental Study of Convective Effects in Loose-Fill Thermal Insulation
Authors: Langlais C , Arquis E , McCaa DJ
Published: March 2009

Experimental results obtained by guarded hot box testing of low density loose-fill insulations have been analyzed using convective models. Closed and open specimens have been studied in an attic configuration with heat flow up. Experiments were conducted with and without a transverse air flow across the top of the specimens. The occurrence of convective movements inside the insulation was investigated for different applied thermal gradients and air permeabilities of insulation. Comparisons between theoretical and experimental results are presented and discussed.

The study has shown that the boundary conditions at the open top surface of an attic insulation are the driving force in determining thermal performance. Both the model and the experiments have shown that a significant reduction in thermal performance for presently used glass fiber insulations can only occur under severe climatic conditions (i.e., where a temperature difference greater than 40°C will be present).
An Acoustic Technique for Evaluation of Thermal Insulation
Authors: Flynn DR , Evans DJ , Bartel TW
Published: March 2009

A laboratory apparatus has been constructed that enables rapid measurement of the sound insertion loss of a sample of insulation as a function of frequency. An extensive series of measurements of the sound insertion losses associated with blown samples of fiberglass, rockwool, and cellulose has been completed; the results of these acoustic measurements are highly correlated with coverage (mass per unit area) and thermal resistance (R-value). An investigation is planned to extend the acoustic techniques used in the laboratory apparatus to in situ determination of the sound transmission loss through thermal insulation installed in attics. Two possible approaches to such field measurements are described.
Thermal Resistances of Metal Frame Wall Constructions Incorporating Various Combinations of Insulating Materials
Authors: Strzepek WR
Published: March 2009

Series of thermal transmission tests were conducted on large wall specimens, which measured 300 by 400 cm (118 by 157 in.), using a calibrated hot box test apparatus. The wall specimens were constructed with metal framing members and were insulated with various combinations of materials.

Wall constructions were tested with and without batt insulation in the wall cavity in an attempt to determine the effect of the metal framing members on the thermal performance of the batts. In addition, the same wall specimens incorporated either wood fiberboard or extruded, expanded polystyrene (XEPS) foam sheathing to examine the effect of the metal framing members on the thermal performance of the sheathing.

The resistance values for the various wall constructions were measured at four different mean temperatures. The test results indicated that the metal framing members significantly reduced the effectiveness of the batt insulation and, to a lesser extent, the effectiveness of the sheathing. However, the batt insulation installed was slightly undersized in the width dimension and did not fill the entire wall cavity. As a result, the effect of the metal framing members on the thermal performance of the batts could not be accurately determined. R-values were calculated for the metal frame wall constructions using several analytical procedures. Some of the calculated values were in reasonably good agreement with the measured values.
Methods for Determining the Thermal Performance of Reflective Insulation Systems
Authors: Miller RG , Oscar DS , Seifaee F , Goss WP
Published: March 2009

There has been no general agreement on how to perform, analyze, and report hot box tests on the thermal performance of reflective insulation systems which consist of a series of airspaces separated by reflective foils. This paper presents the results of experimental and analytical studies on the horizontal heat transfer through single- and multi-layer reflective insulations installed vertically. The multi-layer insulations were commercially available reflective insulation products. The experimental studies were carried out in a guarded hot plate and a calibrated hot box. The results showed the effect of aspect (height to width) ratio on the convective heat transfer in the air space. The experimental results were compared with a detailed three-dimensional finite element model of the conductive, convective, and radiative heat transfer which occurs in the reflective insulation system. The results were also compared with the original references used to determine the thermal resistance of plane reflective air spaces that are presented in the ASHRAE Fundamentals Handbook. These two analytical methods were also used to compare a wood and extruded polystyrene support structure for the reflective insulation product.

The results showed that the guarded hot plate did not adequately model the convective heat transfer, due to the low aspect ratio, and that a full-scale facility is needed to properly test a reflective insulation product. It was also indicated that the thermal performance of reflective insulation products are not comparable with the results for plane reflective airspaces in the ASHRAE Fundamentals Handbook due to the thermal bridges which characterize most reflective insulation products.
Influence of Natural Convection in an Insulated Cavity on the Thermal Performance of a Wall
Authors: Lecompte JGN
Published: March 2009

The influence of the airtightness of the insulation layer in a partially filled cavity construction is discussed. In theory it is assumed that the insulation forms a continuous layer that is perfectly fixed against the inner wall of the cavity, leaving an air space between the outer wall and the insulation. However, in practice we frequently notice the presence of air gaps in the insulation layer, and of a second small cavity between the insulation and the inner wall. The influence of these inaccuracies on the heat transfer is studied by means of experimental research and computer simulations.

This paper presents the results of extensive measurements on a partially filled cavity wall (temperature profiles, heat loss), using a calibrated Hot Box-Cold Box. These results are compared with calculations of the temperature profiles and the overall heat transfer. A second series of measurements deals with the influence of the slope of the cavity.