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Adding parallelism to sequential programs : a combined method

Daszczuk Wiktor B., Czejdo Danny B., Grześkowiak Wojciech

International Journal of Electronics and Telecommunications

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2024

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Vol. 70, No. 1

135--144

EN

The article outlines a contemporary method for creating software for multi-processor computers. It describes the identification of parallelizable sequential code structures. Three structures were found and then carefully examined. The algorithms used to determine whether or not certain parts of code may be parallelized result from static analysis. The techniques demonstrate how, if possible, existing sequential structures might be transformed into parallel-running programs. A dynamic evaluation is also a part of our process, and it can be used to assess the efficiency of the parallel programs that are developed. As a tool for sequential programs, the algorithms have been implemented in C#. All proposed methods were discussed using a common benchmark.

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The influence of surface modification of wood particles with carbon nanotubes on properties of particleboard glued with phenol-formaldehyde resin

Łukawski Damian, Grześkowiak Wojciech, Dukarska Dorota, Mazela Bartłomiej, Lekawa-Raus Agnieszka, Dudkowiak Alina

Drewno : prace naukowe, doniesienia, komunikaty

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2019

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vol. 62, nr 203

93--105

EN

Research was carried out on a newly manufactured particleboard (PB) containing carbon nanotubes (CNTs) to determine the effect of the CNTs on physical, mechanical and combustion properties of the board. The experiment consisted of two stages. In the first, wood particles were treated with an aqueous suspension of CNTs (0.2% w/w) and sodium dodecylbenzenesulfonate (0.2% w/w) as a dispersant. After drying to constant weight, a modified form of the ASTM E69 method was used to determine the effectiveness of fire protection provided by CNT-modified wood chips. The rate of wood decomposition decreased significantly, and the time to complete combustion increased from 18 to 22.5 min for the reference and CNT-modified wood particles respectively. In the second stage of the experiment a particleboard bonded with phenyl-formaldehyde resin was produced, in which the particles were modified with CNTs using the method described in the first stage. Selected physical and mechanical properties of the final board were determined. Samples of the board were tested using a mass loss calorimeter in accordance with the ISO 13927 standard, and mechanical tests were performed by applicable standard methods. However, no significant improvement in the properties of the PB were observed.

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The effect of veneer impregnation with a mixture of potassium carbonate and urea on the properties of manufactured plywood

Kawalerczyk Jakub, Dziurka Dorota, Mirski Radosław, Grześkowiak Wojciech

Drewno : prace naukowe, doniesienia, komunikaty

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2019

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vol. 62, nr 203

197--116

EN

It was determined how the impregnation of birch veneers with a mixture of potassium carbonate and urea affected the fire protection properties, shear strength, modulus of elasticity and modulus of rigidity of plywood glued with PF and UF resin. Veneers were impregnated by soaking in aqueous fire retardant solutions with concentrations of 20% and 30%. Measurements of mass loss, burned area and time of ignition showed the fire protection provided to be very effective. Impregnation did not significantly affect the modulus of elasticity or modulus of rigidity of the plywood. Impregnation caused a decrease in bonding quality, especially in the case of plywood with UF resin soaked in water. For the samples with PF resin, both immersed and boiled in water, impregnation had less impact on the shear strength: its values exceeded 1 N/mm2, thus meeting the requirements of EN 314-2.