Engineering structures stability against progressive collapse

The calculating stability of an engineering structure against progressive collapse is considered in this article. The calculations results are analyzed. A dangerous emergency scenario was developed and measures were developed to prevent the progressive building collapse in the structures local destruction in accordance with the regulatory documents requirements for such an object. The most dangerous design schemes are considered to assess the structure stability against progressive collapse. A scenario for calculating stability against progressive collapse in the case of local failure has been selected, and a consistent action algorithm has been obtained that makes it possible to perform a calculation for resistance to progressive collapse., The kinematic method of the limit equilibrium theory for structures with elastic-plastic materials properties is used to calculate the resistance to progressive collapse. It corresponds to the turning the system into a plastic kinematic chain, the links movement is carried out due to the plastic flow of the system's links. Two types of undamaged structures were identified to assess the building resistance to progressive collapse: neighbouring beams and columns, in which local destruction impact does not cause a qualitative change in the stress state, but leads to an increase in stresses and forces (neighboring beams, columns); pavement slabs resting on a beam and welded through embedded parts to a beam that has lost its original support, and located above a local fracture, the stress state changes. The conclusion is made about the requirements that should be met in order to conclude the calculation justification so it can be said that resistance to progressive collapse is ensured. It has been established that the calculations performed confirm the object stability - the drainage chamber to progressive collapse in the local destruction as an emergency situations result

nticoagulant therapy monitoring in COVID-19 patients in the intensive care unit: thromboelastometry and echocardiography

Aim. To determine the effectiveness of thromboelastometry (TEM) and echocardiography for anticoagulant therapy monitoring in patients with COVID-19.Material and methods. We analyzed treatment regimen of 92 patients with COVID-19. The patients were divided into two groups. In the control group (n=30), anticoagulant therapy with unfractionated heparin (UFH) was carried out under laboratory control of coagulation parameters. In the experimental group (n=62), anticoagulation was maintained by intravenous UFH under control of coagulation, echocardiography (Philips, Epiq 5) and TEM (ROTEM® delta). Echocardiography determined the pulmonary artery acceleration time (AT), mid-systolic notching (SN). The TEM method was used to study external (EXTEM) and internal (INTEM) pathways, differential tests (FIBTEM, HEPTEM) of coagulation. Statistical analysis was performed by calculating non-parametric statistics parameters, comparisons of differences in groups (Mann-Whitney test), area under the curve (AUC), and regression equations.Results. A high correlation level between echocardiographic and TEM parameters was determined. Their levels associated with a positive prognosis were calculated (AT>113,5 ms., AUC 0,979; p<0,0001; no SN, AUC 0,931; p<0,0001; FIBTEM ML (60 min) >1,12%, AUC 0,971, p<0,0001; INTEM ML (60 min) >2,01%, AUC 0,941, p<0,0001, EXTEM ML (60 min) >1,4%, AUC 0,934, p<0,0001; MCFfib not >26 mm, AUC 0,954; p<0,0001; MCFin not >56,6 mm, AUC 0,938; p<0,0001; MCFex not >47,9 mm, AUC 0,838, p<0,0001). In 33,9% of patients in the experimental group, heparin resistance was detected. In this connection, combined therapy with UFH and direct oral anticoagulants (DOACs) was used, followed by the switch to DOACs. In the control group, artificial ventilation was used in 50% of patients, mortality — 36,6%, myocardial infarction — 13,3%, deep vein thrombosis — 6,6%, pulmonary embolism — 6,6%, while in the experimental group, mechanical ventilation — 12,9%, myocardial infarction — 4,8%, mortality — 8,1%.Conclusion. The dynamic assessment of echocardiography and TEM parameters made it possible to monitor pulmonary thrombosis processes, significantly reduce complications, the use of artificial ventilation and mortality in COVID-19 patients

ОЦЕНКА ЭФФЕКТИВНОСТИ АНТИБАКТЕРИАЛЬНОЙ ТЕРАПИИ У ПАЦИЕНТОВ С ВИРУСНО-БАКТЕРИАЛЬНОЙ ПНЕВМОНИЕЙ В 2009/2011 ГОДАХ

Objective: to analyze the efficiency of prescribed antibiotic therapy in patients with viral and bacterial pneumonia of variable severity in the epidemic and postpandemic periods (October 2009 to February 2011).Subjects and methods. Case histories of 85 patients (mean age, 35.92±13.3 years) were retrospectively analyzed; out of them 31 patients were followed up and treated in intensive care units (ICU). The patients were grouped according to PaO2/FiO2: 1) PaO2/FiO2 >300 (n=54); 2) PaO2/FiO2 <300 (n=26); 3) PaO2/FiO2< 200 (n=5).Results. Regression analysis proved the importance of antimicrobial therapy used in admitted patients hav ing risk factors and PaO2/FiO2 > 300. Bacteriological followup revealed that all the patients who had PaO2/FiO2 <200 and died in ICU had been nosocomially reinfected with polyresistant microorganisms and targeted antimicrobial therapy could not be per formed.Conclusion. Early antibiotic therapy in patients with PaO2/FiO2 >300 and risk factors improves the prognosis of the dis ease. All the patients who have PaO2/FiO2 >300 and are ineffectively treated for antibacterial pneumonia should undergo follow up analysis of bronchoalveolar lavage to be switched to targeted antibiotic therapy. The patients who have PaO2/FiO2< 200 are at the highest risk for nosocomial reinfection and pose difficulties in choosing adequate antibiotic therapy. There is a significant relationship between the detection of polyresistant microorganisms and ICU mortality rates.Цель. Анализ эффективности назначенной антибактериальной терапии у больных вирусно-бактериальной пневмонией с разной степенью тяжести в эпидемический и постпандемический период (октябрь 2009 — февраль 2011 года).Материалы и методы. Проведен ретроспективный анализ 85 историй болезни пациентов с средним возрастом 35,92±13,3 года, из которых — 31 наблюдался и проходил лечение в условиях ОРИТ. Деление пациентов на группы произведено по критерию PaO2/FiO2: PaO2/FiO2 >300: 54 пациента; PaO2/FiO2 <300: 26 пациентов; PaO2/FiO2 < 200: 5 пациентов.Результаты. Методом регрессионного анализа доказана важность использования антибактериальной терапии у поступивших пациентов, отягощенных факторами риска с уровнем PaO2/FiO2>300. Исходя из результатов динамического бактериологического исследования, у всех пациентов с PaO2/FiO2< 200 c летальным исходом в условиях ОРИТ выявлен факт внутригоспитальной реинфекции полирезистентной микрофлорой с невозможностью осуществления целенаправленной антибактериальной терапии.Заключение. Раннее использование антибактериальной терапии у пациентов с PaO2/FiO2 >300, отягощенных факторами риска улучшает прогноз заболевания. У всех пациентов с PaO2/FiO2< 300 при неэффективности антибактериальной пневмонии следует проводить динамический анализ бронхо-альвеолярного лаважного содержимого с переходом на целенаправленную антибактериальную терапию. У пациентов с PaO2/FiO2< 200 существует максимально высокий риск нозокомиального реинфицирования с трудностями подбора адекватной антибактериальной терапии. Прослеживается достоверная взаимосвязь выявления полирезистентной флоры и летальностью в условиях ОРИТ

Влияние автооблучения на формирование наноразмерных слоев золота при ионно-лучевом напылении

2–13 nm gold films were obtained by the method of ion-beam sputtering on silicon and quartz substrates. It is shown that the use of an additional operation of deposition followed by the sputtering of a gold layer of 2–3 nm thickness makes it possible to reduce the electrical resistance and surface roughness of the metal films, in comparison with similar films obtained without its use. The results of measuring the temperature coefficient of resistance of nanosized gold films on silicon substrates allowed us to conclude that the films deposited become continuous at a thickness of 6-8 nm. The results of optical measurements of 10 nm gold films, obtained on quartz substrates, showed that the reflection coefficient of electromagnetic radiation at a wavelength of 850 nm is 2.8 % higher than the corresponding coefficient for the same films obtained without using this operation, and is 83 %. An important role in the formation of nanoscale gold layers is played by the processes of self-irradiation of the growing layer of the high-energy component of the gold atoms flux. When using an additional operation of deposition/sputtering, high-energy gold atoms are implanted into the substrate to a depth of about 2 nm. On the one hand, these atoms are point defects in the surface damaged layer of the substrate; on the other hand, they serve as additional centers of cluster formation. This ensures strong adhesion of the metal layer to the substrate and, therefore, the gold films become continuous and more homogeneous in microstructure. The method of ion-beam deposition can be successfully applied to obtain high-quality conductive optically transparent nanosized gold films.Методом ионно-лучевого напыления получены пленки золота толщиной 2–13 нм на кремниевых и кварцевых подложках. Показано, что применение дополнительной операции напыления с последующим распылением слоя золота толщиной 2–3 нм позволяет снизить электрическое сопротивление и поверхностную шероховатость получаемых металлических пленок по сравнению с аналогичными пленками, полученными без ее использования. Результаты измерения температурного коэффициента сопротивления образцов наноразмерных пленок золота на кремниевых подложках позволили заключить, что напыляемые пленки становятся сплошными при толщине 6–8 нм. Результаты оптических измерений пленок золота толщиной 10 нм, полученных на кварцевых подложках, показали, что коэффициент отражения электромагнитного излучения на длине волны 850 нм на 2,8 % выше соответствующего коэффициента для таких же пленок, полученных без использования данной операции, и составляет 83 %. Важную роль в формировании наноразмерных слоев золота играют процессы автооблучения растущего слоя высокоэнергетической составляющей потока атомов золота. При использовании дополнительной операции напыления/распыления происходит внедрение в подложку высокоэнергетических атомов золота на глубину до 2 нм. С одной стороны, эти атомы являются источниками точечных дефектов в приповерхностном нарушенном слое подложки; а с другой – они служат дополнительными центрами кластерообразования. За счет этого обеспечивается высокая адгезия слоя металла к подложке, и, как следствие, пленки золота становятся сплошными и более однородными по микроструктуре. Метод ионно-лучевого напыления может быть успешно применен для получения качественных проводящих оптически прозрачных наноразмерных пленок золота

Применение барьерных слоев диоксида титана для формирования мультиферроиков ферромагнетик/сегнетоэлектрик

The layered multiferroics Co/PZT were obtained by ion-beam sputtering-deposition method, where PZT is a ferroelectric ceramic based on lead titanate zirconate of the composition PbZr0.45Ti0.55O3 with a thermostable plane-parallel ferroelectric/ferromagnet interface. Using cross-sectional scanning electron microscopy (SEM), we studied the interface of a cobalt layer up to several micrometers thick with a thick ceramic substrate of lead zirconate titanate. It has been shown that the use of a titanium dioxide barrier layer of TiO2 instead of PZT allows quality improvement of the interface by reducing the duration of ion-beam planarization of the ferroelectric substrate, and also to eliminate the formation of intermediate chemical compounds. Based on the data of X-ray phase analysis (XRD), it was concluded that the TiO2 layer is amorphous. Magnetoelectric measurements have shown that the use of titanium dioxide instead of PZT under appropriate planarization modes can increase the low-frequency magnetoelectric effect to 5 mV/(cm∙Ое), compared with structures with a sputtering planarizing layer of PZT, where the magnitude of the low-frequency magnetoelectric effect is 2 mV/(cm∙Оe). These results allow us to improve the characteristics of these structures when used as sensitive elements in devices for formation – processing of information and magnetic field sensors based on the magnetoelectric effect.С помощью метода ионно-лучевого распыления – осаждения получены слоистые мультиферроики Co/ЦТС (ЦТС – сегнетоэлектрическая керамика на основе цирконата титаната свинца состава PbZr0,45Ti0,55O3 с термостабильным плоскопараллельным интерфейсом сегнетоэлектрик/ферромагнетик), обладающие воспроизводимыми низкочастотными магнитоэлектрическими характеристиками при комнатной температуре. Методом растровой электронной микроскопии (РЭМ) поперечного сечения исследована граница раздела слоя кобальта толщиной до нескольких микрометров с толстой керамической подложкой цирконата – титаната свинца. Показано, что использование барьерного слоя диоксида титана TiO2 вместо ЦТС позволяет добиться улучшения качества интерфейса за счет уменьшения длительности ионно-лучевой планаризации сегнетоэлектрической подложки, а также исключить образование промежуточных химических соединений. На основе данных рентгенофазового анализа (РФА) сделан вывод об аморфности слоя TiO2, который по сравнению с кристаллическим позволяет более равномерно, без искажений, передавать внутренние напряжения, возникающие между сегнетоэлектрической подложкой и ферромагнитным слоем. Это приводит к более эффективному магнитоэлектрическому взаимодействию и значительному по величине (в единицы – десятки мВ/А) низкочастотному магнитоэлектрическому эффекту при комнатной температуре. Магнитоэлектрические измерения показали, что использование диоксида титана вместо ЦТС при соответствующих режимах планаризации приводит к увеличению низкочастотного магнитоэлектрического эффекта до 5 мВ/(см ∙Э) по сравнению со структурами с напылением планаризующего слоя ЦТС, где величина данного эффекта составляет 2 мВ/(см ∙Э). Эти результаты позволяют улучшить характеристики указанных структур при использовании в качестве чувствительных элементов в устройствах формирования – обработки информации и датчиков магнитного поля на основе магнитоэлектрического эффекта

Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems

Evaluation of the efficiency of antibiotic therapy in patients with viral and bacterial pneumonia in 2009/2011

Objective: to analyze the efficiency of prescribed antibiotic therapy in patients with viral and bacterial pneumonia of variable severity in the epidemic and postpandemic periods (October 2009 to February 2011). Subjects and methods. Case histories of 85 patients (mean age, 35.92±13.3 years) were retrospectively analyzed; out of them 31 patients were followed up and treated in intensive care units (ICU). The patients were grouped according to PaO2/FiO2: 1) PaO2/FiO2 >300 (n=54); 2) PaO2/FiO2 <300 (n=26); 3) PaO2/FiO2 < 200 (n=5). Results. Regression analysis proved the importance of antimicrobial therapy used in admitted patients having risk factors and PaO2/FiO2 > 300. Bacteriological follow-up revealed that all the patients who had PaO2/FiO2 <200 and died in ICU had been nosocomially reinfected with polyresistant microorganisms and targeted antimicrobial therapy could not be performed. Conclusion. Early antibiotic therapy in patients with PaO2/FiO2 >300 and risk factors improves the prognosis of the disease. All the patients who have PaO2/FiO2 >300 and are ineffectively treated for antibacterial pneumonia should undergo followup analysis of bronchoalveolar lavage to be switched to targeted antibiotic therapy. The patients who have PaO2/FiO2< 200 are at the highest risk for nosocomial reinfection and pose difficulties in choosing adequate antibiotic therapy. There is a significant relationship between the detection of polyresistant microorganisms and ICU mortality rates. © 2015 AVES Ibrahim Kara. All rights reserved

Application the Ion Beam Sputtering Deposition Technique for the Development of Spin-Wave Structures on Ferroelectric Substrates

The microwave properties of structures in the form of the 2 μm iron-yttrium garnet (YIG) films, grown by the ion beam sputtering deposition method on epitaxially mismatched substrates of ferroelectric ceramics based on lead zirconate titanate (PZT, PbZr0.45Ti0.55O3), are discussed. The obtained structures were formed and pre-smoothed by the ion beam planarization substrates with the use of an anti-diffusion layer of titanium dioxide TiO2. The atomic force microscopy showed that the planarization of the substrates allows for reaching a nanoscale level of roughness (up to 10 nm). The presence of smooth plane–parallel interfaces of YIG/TiO2 and TiO2/PZT is evidenced by scanning electron microscopy performed in focused gallium ion beams. Ferromagnetic resonance spectroscopy revealed a broadening in the absorption line of the ferrite garnet layers in the resonance ≈ 100 Oe. This broadening is associated with the presence of defects caused by the of the ceramic substrate non-ideality. The estimated damping coefficient of spin waves turned out to be ~10−3, which is two orders of magnitude higher than in an ideal YIG single crystal. The YIG/TiO2/PZT structures obtained can be used for the study of spin waves

Interface magnetoelectric effect in the layered heterostructures with Co layers on the polished and ion-beam planarized ceramic PZT substrates

The low-frequency room temperature interface magnetoelectric (ME) effect was observed in the layered heterostructures comprising the ferromagnetic (FM) Co layers and ferroelectric (FE) ceramic substrates on the base of lead zirconate titanate PbZr0.45Ti0.55O3 (PZT). The Co films 1–12 μm in thickness were deposited by ion-beam sputtering/deposition technics onto the 400 μm PZT substrates. Results of X-ray, magnetic and ME experiments have shown the existence of ME effect in Co/PZT/Co and (Co/PZT/Co)3 heterostructures obtained by the above mentioned techniques being independent on ferromagnetic/ferroelectric interface roughness. The values of ME voltage coefficient in heterostructures with ion-beam planarized PZT surfaces are much higher than that in heterostructures with mechanochemically polished ceramic substrate surfaces. The heterostructures possess ME effect of the same order as those obtained by means of the mechanical bonding of FM and FE sheets with organic binders and have the typical ME hysteresis curves. The structures obtained are perspective for application as energy-independent elements in magnetic field sensors and magnetic memory