36 research outputs found
Library transfer between distinct Laser-Induced Breakdown Spectroscopy systems with shared standards
The mutual incompatibility of distinct spectroscopic systems is among the
most limiting factors in Laser-Induced Breakdown Spectroscopy (LIBS). The cost
related to setting up a new LIBS system is increased, as its extensive
calibration is required. Solving the problem would enable inter-laboratory
reference measurements and shared spectral libraries, which are fundamental for
other spectroscopic techniques. In this work, we study a simplified version of
this challenge where LIBS systems differ only in used spectrometers and
collection optics but share all other parts of the apparatus, and collect
spectra simultaneously from the same plasma plume. Extensive datasets measured
as hyperspectral images of heterogeneous specimens are used to train machine
learning models that can transfer spectra between systems. The transfer is
realized by a pipeline that consists of a variational autoencoder (VAE) and a
fully-connected artificial neural network (ANN). In the first step, we obtain a
latent representation of the spectra which were measured on the Primary system
(by using the VAE). In the second step, we map spectra from the Secondary
system to corresponding locations in the latent space (by the ANN). Finally,
Secondary system spectra are reconstructed from the latent space to the space
of the Primary system. The transfer is evaluated by several figures of merit
(Euclidean and cosine distances, both spatially resolved; k-means clustering of
transferred spectra). The methodology is compared to several baseline
approaches.Comment: 32 pages, 22 figure
Overview of selected hydraulic devices supporting road rescue operations
The intense human activity determines the continuous development of systems and means of transport, which contributes to the intensification of existing road traffic risks and the emergence of new ones. Reduction in the number of fatalities of road accidents is dependent on investment in transport infrastructure, the development of safety systems for means of transport and the care for the technical condition of vehicles. Furthermore, the human factor is manifested in the growing awareness of hazards and improving skills of vehicle drivers. The article presents the construction, operating principles and technical capabilities of the most commonly used hydraulic rescue tools. All this was presented against the background of selected problems occurring during rescue operations while releasing victims caught in car wrecks
Solid State ¹³C Nuclear Magnetic Resonance Study of Morphology and Molecular Mobility in Quenched Poly(3-hydroxybutyrate)
Single pulse magic angle spinning ¹³C NMR spectra and the carbon spin-lattice relaxation times T₁(¹³C) were used for the study of morphology and molecular mobility in poly(3-hydroxybutyrate) quenched in cold water after melting in a twin-screw extruder. The crystallinity of the quenched sample was found to be comparable with that of virgin material, and the decrease in dimensions of the crystallites grown after quenching was deduced from the single pulse magic angle spinning ¹³C NMR spectra. The spin-lattice relaxation curves for the carbons of the CO, CH, CH₂ and CH₃ groups were found to be bi-exponential, which enables the molecular mobility within crystalline and amorphous domains to be studied. The spin-lattice relaxation times T₁(¹³C) estimated for the carbons of the CO, CH, CH₂ groups show the chain mobility enhancement within crystalline domains of the quenched sample, but the influence of the quenching on the CH₃ group rotation and on the main chain motion within amorphous regions was not observed
· - New S = 1/2 "Sawtooth" Chain?
The results of the investigation of magnetic susceptibility, magnetization and specific heat of · (tmen = N,N,N',N'-tetramethylethane-1,2 diamine; tma = 1,3,5-benzenetricarboxylic acid) are reported. The spatial arrangement of magnetic Cu(II) ions and network of covalent bonds suggest that the studied material might be a representative of S = 1/2 sawtooth chain with moderate exchange coupling J/. The investigation of the temperature dependence of susceptibility and magnetic field dependence of magnetization yielding J/ ≈ - 0.63 K is consistent with the structural features. In addition, specific heat data reveal short-range correlations in milikelvin temperature range and indicate long-range ordering below 150 mK
Estimation of the Degree of Crystallinity of Partially Crystalline Polypropylenes Using NMR
The paper deals with a method for the estimation of the degree of crystallinity for partially-crystalline isotactic-polypropylenes (i-PP) using high-resolution solid-state NMR. For this purpose direct polarization MAS NMR spectra were measured for i-PP samples with different degrees of crystallinity at 98°C. The areas beneath the resonance lines in these spectra correspond to the number of carbons in particular functional groups, while the widths and shapes of the lines reflect the degree of crystallinity, crystalline modifications, distribution of chain conformations and the chain mobility. The MAS NMR spectra, measured using appropriate combination of delay time and high proton decoupling field, made it possible to detect only amorphous domains in the sample. This enabled identification of the lines associated with the amorphous domains in the complete MAS NMR spectra and provided sufficient information for reliable estimation of the degree of crystallinity. The heteronuclear Overhauser enhancement of the NMR signals due to short delay time was taken into account in our calculations
Spin Glass State in S=3/2 Kagomé Antiferromagnet
Specific heat, magnetic susceptibility and magnetization of , representing S=3/2 kagomé system are reported. Long-range ordering at 16 K was revealed, however, at lower temperatures slow spin dynamics is still found. The analysis of alternating susceptibility suggests the onset of glassy state. The study of the time dependence of magnetization revealed the existence of more relaxation channels with pronounced different relaxation times. The observed behaviour is consistent with the formation of topological spin glass in which relaxation is governed by both spin and chiral degrees of freedom
Solid State NMR Study of Modified Polyhydroxybutyrate
Structural changes in polyhydroxybutyrate (PHB) brought about by addition of chain extender and/or plasticizer were studied using MAS NMR spectra, which were measured using the direct polarization technique at 30 and 98°C. Four resonances associated with the CO, CH, and groups of PHB were observed in the spectra. The resonance appearing at 98°C shows splitting into two lines related to the crystalline and amorphous regions. Analysis of the resonances made it possible to estimate the influence of applied modifications on crystallinity and distribution of conformations in amorphous and crystalline domains of PHB samples
Chosen aspects of safety of maritime transport in the Baltic Sea Basin
Gospodarka morska jest w szczególny sposób narażona na niebezpieczeństwo ze względu na środowisko swojej działalności. Zagrożenia te wynikają zarówno z działań umyślnych, jak i przypadkowych (warunki hydrometeorologiczne, mechaniczne itp.). Są to zagrożenia zależne i niezależne od człowieka np. środowiskowe, bezpieczeństwo zdrowia i życia ludzi, czy mienia. Pomimo podejmowania prób ograniczania ryzyka niebezpieczeństwa, niemożliwe jest jego całkowite wyeliminowanie. Pomocne mogą być wszelkiego rodzaju systemy bezpieczeństwa, alarmowe, ratunkowe, oraz działania legislacyjne i edukacyjne armatorów i załóg statków do działań obronnych. W artykule przedstawiono wybrane aspekty bezpieczeństwa transportu w basenie morza Bałtyckiego oraz podjęto próbę analizy stanu bezpieczeństwa na tym akwenie.The maritime economy is particularly exposed to danger due to the environment of its operations. These risks result from deliberate actions, as well as incidental (hydrometeorological conditions, mechanical, etc.). These are the threat dependent and independent of human eg. environmental, safety health and life of humans or belongings. In spite of attempts to limit the risk of danger, it is impossible to completely eliminate it. May be helpful here all kinds of security systems, alarm, emergency, legislative and educational of ship owners and crews to the defense activities. The article presents some aspects of the state of transportation safety in the Baltic Sea Basin as well as undertaken the attempt to analyze the security state of this sea area
THE RESEARCH ON AGEING OF GLYCOL-BASED BRAKE FLUIDS OF VEHICLES IN OPERATION
The road safety depends on many factors, including the efficiency of the technical system and the disposal of the driver of the vehicle. As wear of most of the vehicle assemblies threatened only with a breakdown, excessive wear of the braking system components may pose a risk of a traffic accident. The article presents a study on the quality of the brake fluid conductivity as a function of temperature and water content conducted for a selected group of vehicles. This group of vehicles was characterized by different production date and had a different of vehicle mileage. We presented the methodology of statistical analysis of the quality of brake fluid tests in selected 38 passenger vehicles in operation
Research on brake fluids in personal cars
Na bezpieczeństwo w ruchu drogowym składa się wiele czynników, jednym z nich są sprawność techniczna pojazdu i dyspozycja kierowcy. W artykule przedstawiono badania jakości płynu hamulcowego zrealizowane na wybranej grupie samochodów osobowych. W przeprowadzonych badaniach określano temperaturę wrzenia płynu hamulcowego oraz procentową zawartość wody w płynie. Wykazano, że regularna wymiana płynu hamulcowego jest konieczna, a jej optymalna częstotliwość zależy nie tylko od konstrukcji układu, ale przede wszystkim od jakości płynu.The road traffic safety consists of many factors, one of them is technical performance of vehicle and disposition of driver. This paper presents research on the quality of the brake fluid conducted for a selected group of cars. The present study determined the boiling point of the brake fluid and the percentage of water in the fluid. It has been shown that regular replacement of brake fluid is required, and the optimum frequency depends not only on the design of the system, but also on the quality of the liquid