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Purpose There is mounting evidence that surgical patients with COVID-19 have higher morbidity and mortality than patients without COVID-19. Infection is prevalent amongst the trauma population, but any effect of COVID-19 on trauma patients is unknown. We aimed to evaluate the effect of COVID-19 on a trauma population, hypothesizing increased mortality and pulmonary complications for COVID-19-positive (COVID) trauma patients compared to propensity-matched COVID-19-negative (non-COVID) patients. Methods A retrospective analysis of trauma patients presenting to 11 Level-I and II trauma centers in California between 1/1/2019–6/30/2019 and 1/1/2020–6/30/2020 was performed. A 1:2 propensity score model was used to match COVID to non-COVID trauma patients using age, blunt/penetrating mechanism, injury severity score, Glasgow Coma Scale score, systolic blood pressure, respiratory rate, and heart rate. Outcomes were compared between the two groups. Results A total of 20,448 trauma patients were identified during the study period. 53 COVID trauma patients were matched with 106 non-COVID trauma patients. COVID patients had higher rates of mortality (9.4% vs 1.9%, p = 0.029) and pneumonia (7.5% vs. 0.0%, p = 0.011), as well as a longer mean length of stay (LOS) (7.47 vs 3.28 days, p p = 0.008), compared to non-COVID patients. Conclusion This multicenter retrospective study found increased rates of mortality and pneumonia, as well as a longer LOS, for COVID trauma patients compared to a propensity-matched cohort of non-COVID patients. Further studies are warranted to validate these findings and to elucidate the underlying pathways responsible for higher mortality in COVID trauma patients.

The present study considers the possibility of developing an integrated system for monitoring the basic parameters of the braking system of cars in operation during the braking process. The main parameters determining the braking efficiency of cars are the temperature of the brake system elements and the brake fluid pressure. Experimental studies and developments have been carried out to determine the temperature of the car's brake discs during braking.

The oscillations of a signal, collected by a ring electrode with +50 V potential, situated in the plasma over the welding zone during electron beam welding (EBW) with local beam deflection oscillations were studied. Samples of chrome-molybdenum steel were processed. The frequencies of the beam oscillations varied between 150 and 1400 Hz and their trajectories were the simplest: along and across the joint. The position of the beam focus was changed. Fluctuations of the emitted plasma current by coherent accumulation of the signal amplitudes were analysed and the probability for instability excitations in the keyhole was estimated. This method allows the study of the random instability processes at the interaction of the beam with the keyhole wall and bottom. A time shift between the maxima of the function derived from the coherent accumulation and the extremes of the deflection coil current was found. This shift depends on the beam focus position. In addition, at longitudinal beam oscillations, and at variations of the focus position a difference of the extreme values of the studied signal was observed. At the lowest values of the current of the focusing electromagnetic lens, the differences between the maxima of the probabilities for excitation of the plasma signal oscillations in the moments at beam bombardment on the front and trailing walls of the keyhole in the molten pool were about 30%, while the beam over-focusing decreased these differences. For beams situated at the central part of the keyhole, the collected signal was minimal. From the observations of spikes in the weld root, at EBW with deflection oscillations, it was concluded that self-focusing of the beam in the bottom part of the keyhole in the cases of the most focusing positions was occurring.

Thin films of cerium dioxide were deposited on silicon (100) substrates using e-beam evaporation. The influence of different technological parameters, such as the substrate temperature, the oxygen pressure and the beam power on the crystallographic orientation of the films was explored. By optimizing these parameters, CeO 2 thin films with a strongly preferred (200) orientation could be deposited on Si(lOO) substrates.

In this chapter we describe the basic steps when modeling the ion and electron exposure processes in multilevel multicomponent amorphous targets. The modeling of the exposure process in EIL involves the simulation of particle penetration into materials as well as the calculation of the absorbed energy distribution within the targets. The models presented for the exposure process simulation are realized by means of a software package. Using our simulation tools the effects of: irradiated particles (electrons and ions), exposure doses, substrates and dense patterns are discussed in order to extract the necessary values for high resolution patterning. EBL simulation of the exposure process was carried out in the case of semiconducting and superconducting substrates using the developed models and the computer programs. For the calculation of energy deposition in the resist film due to a point beam (EDF(r,z)) a MC simulation was applied. The problem concerning the insufficient statistics of the discrete data for the absorbed energy in the case of large lateral distances is overcome. In the Si case, the EDF(r) is approximated by a sum of two Gaussian functions, while in the case of YBCO layers deposited on STO or MgO substrates, the EDF(r) could be approximated as a combination of a double Gaussian and an exponential function. In this case the division of scattering electrons into forward and backward is not the same as for Si samples since the backscattering from YBCO film is important in the middle region of the EDF(r) (from ~ 40 nm to 2 m). Data for the scattering parameters, such as standard deviations of EDF(r), was obtained. A methodology and a computer program are proposed for the calculation of the absorbed energy integral space distribution when exposing real topological structures in EBL, using analytical expressions. The simulation results were compared to the experimental and other calculated data in the case of Si and YBCO/STO(MgO) substrates and the agreement was good. A program version, named TRIM-MV, for exposure process modeling at IBL, based on the famous Biersack model, is developed. From the detailed simulation study, significant information on the energy losses, ranges and moments of the space distributions for different ions is obtained. It is concluded that the exposure with He ions with energies from 60 to 100 keV is favorable for sub-150 nm region. On the basis of our experimental and calculated results, it is assumed that the electronic energy losses are responsible for solubility modification of polymer resists in IBL. The nuclear stopping power has an effect on the solubility modification in the case of heavy low-energy ion irradiation at non-linear (multiciphered) development rates. The obtained results and comparisons show that the models for exposure process modeling at EBL and IBL are adequate and have a very good potential for application in the case of multiplayer sub-quarter-micron patterns. The simulation results are very useful when optimizing particular technological processes for complex layouts in the sub-quarter-micron lithography. The ion lithography should be considered as one of the competitors for further improvement of the integration level of the produced integral circuits.

The interest in renewable energy sources (RESs) utilisation and energy efficiency improvement programmes in Bulgaria reflects the changes in the field of energy policy worldwide and in Europe. Now energy management becomes a great problem of inner policy of Bulgarian government. In the last few years there has been a growing attention to the RESs applications. Bulgaria has one of Southern European countries with richest renewable energy resource base. Bulgarian EU-backed target is for 16% RESs of all energy generation by 2020. The paper presents the status of renewable energy technologies and their installed capacities. The opportunities and constraints for further development and use of renewable energy are considered. There are given data for energy balance, dwellings and one illustrative example of energy efficiency improvement of one multi-dwelling panel house, typical for a lot of Bulgarian citizens in small and big towns.

C-axis oriented 100-nm thick YBCO films were deposited on LaAlO3 (100) substrates at substrate temperature of 780?C in a mixed oxygen/argon atmosphere (1:3) of 0.3 Torr by DC off-axis magnetron sputtering. The samples deposited were thermally annealed in oxygen ambient of 600 Torr at 530?C for 40 min. Superconductivity with zero resistance 89.1K was observed for the YBCO films after annealing. These results show that thermal annealing is an important technique for improving the parameters of thin superconducting films. A correlation between the YBCO layers properties before and after annealing was established.

In this paper, experimental results for different regimes, data for chemical analysis and theoretical investigation of the process parameters at electron beam melting and refining (EBMR) of hafnium samples are presented and discussed. Thermodynamics conditions and mechanisms as possibilities for the refining process Hf are described and analyzed. Calculated data for the refining kinetics of EBMR of Hf shows that the refining rate is determined not only by the process of mass transport of the impurities through the liquid metal and by the evaporation from the molten pool surface, but also by a great extent by other processes. The results show that the minimal impurities’ concentrations are obtained at 12 kW electron beam power and short heating time.