Interlaboratory Comparison of the Thickness of the Destroyed Surface Layer of Closed-Cell Foam Insulation Specimens

2007 ◽  
Vol 4 (1) ◽  
pp. 100321
Author(s):  
TK Stovall ◽  
P Mukhopadhyaya ◽  
M Kumaran ◽  
SW Dean
Keyword(s):  
Surface Layer ◽  
Interlaboratory Comparison ◽  
Closed Cell ◽  
Cell Foam

Temperature dependency of the long-term thermal conductivity of spray polyurethane foam

2021 ◽  
pp. 174425912110454
Author(s):  
Neal Holcroft
Keyword(s):  
Thermal Conductivity ◽  
Polyurethane Foam ◽  
Cellular Structure ◽  
Gas Diffusion ◽  
Temperature Dependent ◽  
Blowing Agent ◽  
Closed Cell ◽  
Wall Assembly ◽  
Cell Foam

The thermal properties of closed-cell foam insulation display a more complex behaviour than other construction materials due to the properties of the blowing agent captured in their cellular structure. Over time, blowing agent diffuses out from and air into the cellular structure resulting in an increase in thermal conductivity, a process that is temperature dependent. Some blowing agents also condense at temperatures within the in-service range of the insulation, resulting in non-linear temperature dependent relationships. Moreover, diffusion of moisture into the cellular structure increases thermal conductivity. Standards exist to quantify the effect of gas diffusion on thermal conductivity, however only at standard laboratory conditions. In this paper a new test procedure is described that includes calculation methods to determine Temperature Dependent Long-Term Thermal Conductivity (LTTC(T)) functions for closed-cell foam insulation using as a test material, a Medium-Density Spray Polyurethane Foam (MDSPF). Tests results are provided to show the validity of the method and to investigate the effects of both conditioning and mean test temperature on change in thermal conductivity. In addition, testing was conducted to produce a moisture dependent thermal conductivity function. The resulting functions were used in hygrothermal simulations to assess the effect of foam aging, in-service temperature and moisture content on the performance of a typical wall assembly incorporating MDSPF located in four Canadian climate zones. Results show that after 1 year, mean thermal conductivity increased 15%–16% and after 5 years 23%–24%, depending on climate zone. Furthermore, the use of the LTTC(T) function to calculate the wall assembly U-value improved accuracy between 3% and 5%.

scholarly journals Study of Physical Properties and Shock Absorption Abilities of Starch Polymer Foam as Cushioning Material for Packaging

2018 ◽  
Vol 225 ◽  
pp. 06010
Author(s):  
N. Amir ◽  
Mohamed Syakir Mohamed Hisham ◽  
Kamal Ariff Zainal Abidin
Keyword(s):  
Average Density ◽  
Curing Process ◽  
Polymer Foam ◽  
Shock Absorption ◽  
Open Cell ◽  
Lack Of Information ◽  
Closed Cell ◽  
Open Cell Foam ◽  
Cell Foam ◽  
Cushioning Material

Lack of information about the formulation and fabrication process of starch polymer foam and lack of study in the shock absorption ability of starch polymer foam were the reasons this research was executed. In this project starch polymer foam was produced to be used as cushioning material for packaging. Starch polymer foam were developed from starch, polyvinyl alcohol (PVA), urea, citric acid, and deionised water. Water amount with drying and curing process were the variables manipulated to produce the best starch polymer foam. It was determined then, that the optimized ratio of starch:PVA:citric acid was 1:1:4. The amount of water used was 10 ml/gram of starch/PVA weight. The suitable foaming mixing was done at a speed of 1500 rpm for 40 minutes. Drying process was done at 70°C for 24 hours, followed by curing process at 100°C for 1 hour to produce closed-cell foam. While for the open-cell foam, the foam was dried and cured at 100ºC for 6 hours. The open-cell and closed-cell foams produced were cut to 6 cm height x 6 cm width x 0.5 cm thick. The average density was calculated and then the foams were subjected to weight drop destructive test. The test was done by placing a foam on top of a piece of mirror, and a weight is dropped onto the foam, with increasing height until the mirror break. Three weights were used with mass of 50 g, 100 g and 200 g. The starch foams were compared to polyurethane and polystyrene foams in terms of the minimum height that can cause the mirror to break. The results showed that starch closed-cell foam absorbed the highest impact energy followed by polystyrene foam, starch open-cell foam and polyurethane foam.

Open-Cell Foam Metal Production and Characterization by Aluminum Solid Mold Investment Casting

2019 ◽  
Author(s):  
Kerem Altug Guler
Keyword(s):  
Investment Casting ◽  
Replication Process ◽  
Open Cell ◽  
Metal Fabrication ◽  
Cell Structures ◽  
Closed Cell ◽  
Small Complex ◽  
Open Cell Foam ◽  
Foam Metal ◽  
Cell Foam

Foam metals can be categorized in two basic classes: open-cell and closed-cell structures, which both have different numerous unique properties. Up to the present, several production processes have been developed for each class. Investment casting is known as a replication process for open-cell foam metal fabrication. Solid mold, which can be evaluated as a subtechnique of the investment casting, is specialized especially for small complex shapes with ultrathin sections. This work is a presentation of aluminum open-cell foam production with solid mold investment casting using two different kinds of patterns. The first one is “burnable,” in which liquid metal directly fills the shape of pattern and the second is “leachable,” in which metal takes the form of intergranular network shape of porous salt preforms.

scholarly journals Microstructural and Chemical Analysis of Polyurethane and Polyisocyanurate Foam Insulations

2021 ◽  
Author(s):  
Umberto Berardi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Performance ◽  
Cell Structure ◽  
Polymer Degradation ◽  
Chemical Characterization ◽  
Aging Behavior ◽  
Blowing Agent ◽  
Closed Cell ◽  
Physical Attributes ◽  
Cell Foam

For some closed cell foam insulation products, the thermal conductivity increases at low temperatures, contrary to single thermal resistance values provided by manufacturers. This phenomenon has been demonstrated in various polyurethane and polyisocyanurate insulations. The reduction in thermal performance has been attributed to the diffusion of air and blowing agent through the foam and to the condensation of blowing agent. Aging processes such as freeze-thaw cycling, moisture accumulation, and polymer degradation further increase thermal conductivity. The initial cell structure plays a role in dictating the thermal performance. To further understand the loss of thermal performance in closed cell foams, microstructure and chemical characterization was performed in this study. The aging behavior of foam insulations was analyzed by imaging foams with SEM and by measuring foam. Changes in the polymer physical attributes were identified and compared to increases in thermal conductivity. This project also used gas chromatography and quantified changes in pentane concentration in polyisocyanurate foams that have undergone aging

Closed Cell Foam: A Sound Barrier and More

2005 ◽  
Author(s):  
Mark Smith ◽  
Waldemar Semrau
Keyword(s):  
Sound Barrier ◽  
Closed Cell ◽  
Cell Foam

scholarly journals Barking up the right tree: comparative use of arboreal and terrestrial artificial refuges to survey reptiles in temperate eucalypt woodlands

2018 ◽  
Vol 45 (2) ◽  
pp. 185 ◽  
Author(s):  
Damian R. Michael ◽  
Daniel Florance ◽  
Mason Crane ◽  
Wade Blanchard ◽  
David B. Lindenmayer
Keyword(s):  
Survey Methods ◽  
Natural Habitat ◽  
Basal Area ◽  
Agricultural Landscapes ◽  
Mature Trees ◽  
Detection Rates ◽  
Closed Cell ◽  
Eastern Australia ◽  
Non Destructive ◽  
Cell Foam

Context Artificial refuges (cover boards) are a popular method to survey and monitor herpetofauna worldwide. However, one limitation of using artificial refuges in terrestrial environments is the low detection rates of arboreal species. Furthermore, destructive search techniques can damage critical microhabitat such as exfoliating rock or flaking bark of mature trees. Aim We tested a non-destructive, passive method of sampling arboreal reptiles in fragmented agricultural landscapes in south-eastern Australia. Methods We installed 84 artificial bark refuges consisting of strips of non-toxic, closed-cell foam attached to eucalypt trees in 13 patches of remnant vegetation. We used Bayesian statistics to compare differences in detection rates among artificial bark refuges, terrestrial artificial refuges and active searches of natural habitat over a 4-year period. Key results Active searches combined with terrestrial artificial refuges detected the highest number of reptile species, including several cryptic fossorial species. Artificial bark refuges detected, on average, 132 times more individuals of the arboreal southern marbled gecko, Christinus marmoratus, than did terrestrial refuges. Gecko abundance patterns were related to tree characteristics such as tree size, bark thickness and stand basal area, as well as survey year. Conclusions Traditional survey methods such as terrestrial cover boards, in combination with active searches of natural habitat, may significantly underestimate counts for arboreal gecko species. Implications Artificial bark refuges provide a cost-effective, non-destructive and durable method for surveying and monitoring arboreal reptiles in woodland environments over short to medium time frames. Foil-backed, closed-cell foam has broad application for use in spatial capture–recapture studies and long-term monitoring of arboreal reptiles. This method also may be effective for procuring records of threatened arboreal geckos or as a solution for providing temporary habitat in ecological restoration projects.

Treated knitted fabric for hip protective pads for elderly women. Part II. Performance relevant to thermal comfort

2019 ◽  
Vol 89 (23-24) ◽  
pp. 5006-5013 ◽  
Author(s):  
Wiah Wardiningsih ◽  
Olga Troynikov
Keyword(s):  
Thermal Comfort ◽  
Hip Fractures ◽  
Isopropyl Alcohol ◽  
Elderly Women ◽  
Treatment Method ◽  
Closed Cell ◽  
Spacer Fabric ◽  
Spacer Fabrics ◽  
Tetraisopropyl Titanate ◽  
Cell Foam

This paper describes Part II of a study of hip protective pads made from spacer fabric treated with shear thickening fluid (STF). Hip fractures are a substantial contributor to morbidity and mortality in the elderly, and incidence is rising worldwide. Hip protective pads reduce fractures, but wearing adherence is poor. Pads made from breathable and comfortable fabrics can increase adherence and prevent more hip fractures. In this research, warp-knitted spacer fabrics were treated with STF using one of two methods. Treatment I involved STF and room temperature vulcanizing (RTV) silicone, while treatment II consisted of STF and a mixture of isopropyl alcohol and tetraisopropyl titanate. In Part I, STF-treated knitted spacer fabric was shown to have significantly greater force attenuation capacity than untreated fabric and comparable to force attenuation capacity of closed cell foam. In Part II, the effects on performance relevant to the thermal comfort of the wearer of each treatment method, the amount of STF used, and layering were assessed using a sweating guarded hot plate, and comparisons made between treated fabrics and with closed cell foam. Treatments I and II produced pads with significantly different permeability index and mass compared to closed cell foam. Treatment II produced pads with high force attenuation capacity, suitable permeability indexes, and low mass – preferred characteristics in hip protective pads. The study concluded that knitted spacer fabrics treated with STF, isopropyl alcohol, and tetraisopropyl titanate are potentially useful materials for hip protective pads.

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