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  • Author: Paweł Szymański x
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Abstract

The combat potential of future warships will be directly related to the use of modern electronic devices being parts of advanced systems, such as, for instance, radar systems, fire aiming systems, fire detection systems, electric drive systems, and even electronic and radio-electronic weaponry, railguns and lasers, installed on these warships. The capacity and functionality of these devices is continually increasing, at decreasing mass and dimensions, which results in higher power consumption. Heat collection becomes a growing problem in operation of these devices.

The paper presents a concept of the use of the CPL (Capillary Pumped Loop) cycle for passive heat collection from precise electronic devices used on warships. It also includes the description of the experimental rig and discussion of the results of laboratory tests performed on this rig and confirmed using the mathematical model developed by the authors.

Abstract

Article presents the results of the effect of humidity on early shrinkage of normal concrete with variable W/C ratio. As known for a long time, shrinkage is dependent of many factors. One of them is the W/C ratio and the quantity of water which is located in the concrete mix. In article there were discussed changes taking place in the concrete mix, the methods of research and the partial results obtained by the authors of the paper. Shrinkage is a phenomenon well known and studied by various research centers. The total amount of shrinkage may depend on various factors such as humidity, temperature, composition of the concrete mix, the W/C ratio, the size of the item. The study was conducted to determine the amount of shrinkage in its early stages. It is very important for concrete floors contractors, precast manufacturers to start at the right time finishing work and prevent the formation of shrinkage cracks.

Abstract

The lipophilicity of thirty-two novel acetylcholinesterase (AChE) inhibitors — 1,2,3,4-tetrahydroacridine and 2,3-dihydro-1H-cyclopenta[b]quinoline derivatives was studied by thin layer chromatography. The analyzed compounds were chromatographed on RP-18, RP-8, RP-2, CN and NH2 stationary phases with dioxane — citric buffer pH 3.0 binary mobile phases containing different proportions of dioxane. RM values for pure water were extrapolated from the linear Soczewiński-Wachtmeister equation and six compounds with known literature log P values were used as reference calibration data set for computation of experimental log P values. The obtained results were compared with computationally calculated partition coefficients values (AlogPs, AClogP, AlogP, MlogP, KOWWIN, XlogP2, XlogP3) by PCA and significant differences between them were observed.

Abstract

This article describes the simulations of the scattering of annihilation γ quanta in a strip of a plastic scintillator. Such strips constitute the basic detection modules in a newly proposed positron emission tomography (PET), which utilizes plastic scintillators instead of inorganic crystals. An algorithm simulating the chain of Compton scatterings was elaborated and a series of simulations have been conducted for the scintillator strip with a cross-section of 5×19 mm. The results indicate that secondary interactions occur only in the case of about 8% of the events and only 25% of these events take place in the distance larger than 0.5 cm from the primary interaction. Also, the light signals produced at the primary and secondary interactions overlap with the delay, the distribution of which is characterized by a full width at half-maximum (FWHM) of about 40 ps.

Abstract

A novel PET detector consisting of strips of polymer scintillators is being developed by the Jagiellonian Positron Emission Tomograph (J-PET) collaboration. The map of efficiency and the map of geometrical acceptance of the two-strip J-PET scanner are presented. The map of efficiency was determined using the Monte Carlo simulation software GEANT4 Application for Tomographic Emission (GATE), which is based on GEANT4. Both maps were compared using a method based on the χ2-test.

Abstract

Using a theory of list-mode maximum likelihood expectation-maximization (MLEM) algorithm, in this contribution, we present a derivation of the system response kernel for a novel positron emission tomography (PET) detector based on plastic scintillators.

Abstract

Photomultipliers are commonly used in commercial PET scanner as devices that convert light produced in scintillator by gamma quanta from positron-electron annihilation into electrical signal. For proper analysis of obtained electrical signal, a photomultiplier gain curve must be known, since gain can be significantly different even between photomultipliers of the same model. In this article, we describe single photoelectron method used for photomultiplier calibration applied for J-PET scanner, a novel PET detector being developed at Jagiellonian University. A description of calibration method, an example of calibration curve, and a gain of few Hamamatsu R4998 photomultipliers are presented.