The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Tomáš Vít - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of CAE Methods Used for Plate Heat Exchanger Design
Energy Procedia, 2017Co-Authors: Václav Dvořák, Tomáš VítAbstract:Abstract Flow and heat transfer in a plastic recuperative counter flow plate air-to-air heat exchanger were investigated experimentally and numerically using Ansys Fluent software. It was employed previously developed methods to generate a computational mesh and assumed nonzero thickness of the plates to calculate the flow in an air-to-air heat exchanger. Pressure drop and effectiveness were evaluated as functions of inlet velocity. Obtained numerical data were substituted by suggested functions dependent on the Reynolds number and later modified to take change in plate pitch and material thickness into account. It was found that change in plate pitch influence only friction losses due to change of turbulence of the flow. The shape of mini-channels, which are defined by the shape of pressing molds that are constant during our investigation, determines local loses. Increasing the plate pitch has the same effect on Nusselt number as increasing the Reynolds number. Modified functions were used to illustrate the effect of material thickness, plate pitch and heat conductivity of material on pressure drop and effectiveness. Derived equations witch take the effect of material thickness and plate pitch into account represent a useful tool for design and optimization of recuperative heat exchanger for use in HVAC systems in sustainability buildings.
D. Yu. Murzin - One of the best experts on this subject based on the ideXlab platform.
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Valorization of cellulose over metal supported mesoporous materials
Catalysis Today, 2011Co-Authors: M. Käldström, Narendra Kumar, D. Yu. MurzinAbstract:Abstract Hydrolytic hydrogenation of bleached birch (betula) kraft pulp from a Finnish pulp mill into sugars and sugar alcohols was carried out in liquid phase in a batch mode under 20 bar of hydrogen at 458 K over metal supported mesoporous materials. Proton form of MCM-48 mesoporous material along with Pt on this support and Ru on carbon was tested. The conversion of cellulose and xylans present in the pulp varied depending on type of active sites, their number and metal. The yields of the main products, e.g. sugars, sugar alcohols and furfurals (xylose, glucose, xylitol, sorbitol, furfural, furfuryl alcohol and 5-hydroxymethyl furfural), varied depending on active sites, acidity, presence of metal and structure of the mesoporous material.
Torben Sigsgaard - One of the best experts on this subject based on the ideXlab platform.
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Are allergen batch differences and the use of double skin prick test important?
BMC Pulmonary Medicine, 2015Co-Authors: Gert F Thomsen, Lars Rauff Skadhauge, Tine Halsen Malling, David Lee Sherson, Øyvind Omland, Vivi Schlünssen, Torben SigsgaardAbstract:Background Skin prick tests (SPT) are widely used both in clinical diagnostics and in research. The standardization of allergen extracts is well documented to be crucial for the validity of SPT, whereas less emphasis has been placed on reproducibility and the SPT procedure itself. The objectives of this study are to clarify how the double skin prick test procedure influence the sensitivity and specificity of the test and to analyse the differences in weal size in skin prick tests between two batches of allergen extracts from the same vendor. Methods The association between rhinitis and SPT was assessed among 1135 persons from a general population sample. SPT was performed twice with 10 common aeroallergens. In a subsample of 90 persons SPT was performed simultaneously with five of the allergens using different batches. Results Thirty percent had at least one positive SPT. Among asthmatics this number was 62%. Only minor differences were seen between the sizes of two weals from the same batch. A second SPT with the same batch did not change the association between rhinitis and sensitization. When performing SPT with two different batches disagreement was observed in 2% (Birch) to 11% (Cat) of the subjects. Conclusions Performing SPT twice with the same allergen batch does not enhance the validity of the test, and value of double testing can be questioned. Considerable differences in SPT response with different batches from the same manufacturer were observed. Thus inter batch differences in allergen extracts might be a source of variability.
Torben Sigsgard - One of the best experts on this subject based on the ideXlab platform.
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Skin prick test allergen batch differences and duplicate skin prick tests: Which are important?
European Respiratory Journal, 2014Co-Authors: Gert Thomsen, Lars Rauff Skadhauge, Tine Halsen Malling, David Lee Sherson, Øyvind Omland, Vivi Schlünssen, Torben SigsgardAbstract:Background: Skin prick tests (SPT) are widely used both in clinical practice and in research. The standardization of the allergen extracts is well documented to be crucial for the validity of SPT, whereas less emphasis has been on reproducibility and the SPT procedure itself. Objective: To study how the duplicate skin prick test procedure influence the sensitivity and specificity of the test and to analyse the differences in wheal size in skin prick tests with two batches of allergen extracts from same vendor. Methods: The association between rhinitis and SPT was assessed among 1135 subjects from a general population sample. SPT was performed twice with 10 common aeroallergens. In a subsample of 90 persons SPT was performed simultaneously with five of the allergens using two different batches Results: Thirty percent had at least one positive SPT. Only minor disagreements were seen between the sizes of two wheals from the same batch. A second SPT with the same batch did not change the association between rhinitis and sensitization. When performing SPT with two different batches disagreement was observed in 2 % (Birch) to 11% (Dog) of the subjects. Conclusions: Performing SPT twice with the same allergen batch does not enhance the validity of the test, and duplicate testing cannot be recommended. Considerable difference in SPT response was observed when using different batches from the same vendor. Thus, inter batch differences in allergen extracts might be a source of variability.
Tine Halsen Malling - One of the best experts on this subject based on the ideXlab platform.
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Are allergen batch differences and the use of double skin prick test important?
BMC Pulmonary Medicine, 2015Co-Authors: Gert F Thomsen, Lars Rauff Skadhauge, Tine Halsen Malling, David Lee Sherson, Øyvind Omland, Vivi Schlünssen, Torben SigsgaardAbstract:Background Skin prick tests (SPT) are widely used both in clinical diagnostics and in research. The standardization of allergen extracts is well documented to be crucial for the validity of SPT, whereas less emphasis has been placed on reproducibility and the SPT procedure itself. The objectives of this study are to clarify how the double skin prick test procedure influence the sensitivity and specificity of the test and to analyse the differences in weal size in skin prick tests between two batches of allergen extracts from the same vendor. Methods The association between rhinitis and SPT was assessed among 1135 persons from a general population sample. SPT was performed twice with 10 common aeroallergens. In a subsample of 90 persons SPT was performed simultaneously with five of the allergens using different batches. Results Thirty percent had at least one positive SPT. Among asthmatics this number was 62%. Only minor differences were seen between the sizes of two weals from the same batch. A second SPT with the same batch did not change the association between rhinitis and sensitization. When performing SPT with two different batches disagreement was observed in 2% (Birch) to 11% (Cat) of the subjects. Conclusions Performing SPT twice with the same allergen batch does not enhance the validity of the test, and value of double testing can be questioned. Considerable differences in SPT response with different batches from the same manufacturer were observed. Thus inter batch differences in allergen extracts might be a source of variability.
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Skin prick test allergen batch differences and duplicate skin prick tests: Which are important?
European Respiratory Journal, 2014Co-Authors: Gert Thomsen, Lars Rauff Skadhauge, Tine Halsen Malling, David Lee Sherson, Øyvind Omland, Vivi Schlünssen, Torben SigsgardAbstract:Background: Skin prick tests (SPT) are widely used both in clinical practice and in research. The standardization of the allergen extracts is well documented to be crucial for the validity of SPT, whereas less emphasis has been on reproducibility and the SPT procedure itself. Objective: To study how the duplicate skin prick test procedure influence the sensitivity and specificity of the test and to analyse the differences in wheal size in skin prick tests with two batches of allergen extracts from same vendor. Methods: The association between rhinitis and SPT was assessed among 1135 subjects from a general population sample. SPT was performed twice with 10 common aeroallergens. In a subsample of 90 persons SPT was performed simultaneously with five of the allergens using two different batches Results: Thirty percent had at least one positive SPT. Only minor disagreements were seen between the sizes of two wheals from the same batch. A second SPT with the same batch did not change the association between rhinitis and sensitization. When performing SPT with two different batches disagreement was observed in 2 % (Birch) to 11% (Dog) of the subjects. Conclusions: Performing SPT twice with the same allergen batch does not enhance the validity of the test, and duplicate testing cannot be recommended. Considerable difference in SPT response was observed when using different batches from the same vendor. Thus, inter batch differences in allergen extracts might be a source of variability.