Remote ultra-wideband tomography of nonlinear electronic components

The efficiency of using ultra-wideband (UWB) signals for nonlinear radar is investigated. In the case at hand, it is necessary to see, based on scattered field disturbances, whether nonlinear inclusions are present in the field of view. The solution suggested is to compare the shapes of UWB signals reflected from the probe area under two conditions: an additional generator irradiating the probe area by intense monochromatic radiation is switched on and off. If a nonlinear electronic component is present in the probe area, the reflected UWB signals differ in shape. Thus, the difference in the shapes of the signals indicates the presence of a component with a nonlinear characteristic

Application of broadband microwave near-field sensors for glucose monitoring in biological media

The paper presents results of numerical simulation and experimental testing of a microwave sensor for non-invasive glucose monitoring. The sensor represents a conical horn with a conical conductor inside expanding toward the horn aperture. Such a sensor has a significantly wider passband in comparison with sensors of other designs. It is essential that the sensor geometry provides formation of an extended near-field zone with high electric field strength near the sensor aperture. A clear relationship between the dielectric permittivity of the phantom biological tissue and the frequency dependence of the parameter S11 of the sensor is observed at frequencies in the range from 1.4 to 1.7 GHz. This circumstance can be used to develop a procedure for measuring the glucose level in blood that correlates with the parameter S11 of the sensor. From the viewpoint of monitoring of the glucose content in blood, the most convenient body sensor location is on the hands or feet, in particular, wrists

A comprehensive study of underground animals habitat

This paper describes a method of studying the natural habitats of underground animals by the example of zokor. The purpose of the research is to find habitation of animals using unmanned aircraft and investigate networks of tunnels and burrows with ground penetrating radar "OKO-2". Geolocation data were processed by techniques developed by the authors

Additive manufacturing of crack-free Al-alloy with coarsening-resistant τ<inf>1</inf>-CeAlSi strengthening phase

Wrought aluminium alloys popular for automotive and aerospace applications are susceptible to solidification cracking when fabricated via laser powder bed fusion (LPBF). Another long-standing and common issue for these alloys is microstructure coarsening and corresponding strength loss caused by elevated temperature exposure. To tackle these challenges, this study designs and develops a class of 1–4 wt% Ce modified Al6061 alloys. The best alloy, with 3 wt% Ce, achieves crack-free fabrication via LPBF due to a reduction in the solidification temperature range and a new solidification pathway that achieved 0.9 solid mass fraction at just 14 °C below the solidification onset. Furthermore, a fine microstructure consisting of coarsening-resistant τ1-CeAlSi eutectic forms, and after hot isostatic pressing, the tensile strength and elongation of the 3 wt% Ce alloy can reach 153 ± 6 MPa and 18.3% at room temperature and 89 ± 6 MPa and 32.5% at 200 °C, respectively. The observed ductility is attributed to nanoscale dispersion of discrete, coarsening resistant τ1-CeAlSi particles within grains and to the presence of large columnar α-Al grains. Meanwhile, solidification cracking was inhibited by continuous grain boundary τ1-CeAlSi eutectic accumulation, which converted to discrete nanoscale τ1-CeAlSi after hot isostatic pressing. This research uncovers a simple and effective approach of designing Al-alloys for LPBF with great potential for both room temperature and high temperature applications in automotive and aerospace industries

Fresnel flat reflector with focusing capability

Theoretical modeling of a Fresnel flat reflector for focusing radiation in the point near the reflector is discussed in this paper. It shows that the reflector calculated for one frequency and one focus position can also be used for other frequencies, but a focusing point should be shifted along a focusing line. Fresnel reflector can be used for a space-frequency filtration in a wide frequency range

Influence of the composition on the thermoelectric and electro-physical properties of Ge-Sb-Te thin films for phase change memory application

Influence of the composition variation along the quasi-binary line GeTe-Sb2Te3 on the thermoelectric and electro-physical properties of thin films was investigated. GST amorphous thin films have high Seebeck coefficients, which drops nearly on the order of magnitude after the crystallization. Temperature dependences of the resistivities were studied, and it was determined that crystallization temperature increases with moving along the quasi-binary line GeTe-Sb2Te3 from GeSb4Te7 to GeSb2Te4, and then to Ge2Sb2Te5, while the phase transition temperature range decreases. Current-voltage characteristics of amorphous thin films have three voltage ranges with different dependencies due to the different mechanisms of charge carrier transport

Clinical impact of baseline chronic kidney disease in patients undergoing transcatheter or surgical aortic valve replacement

ObjectivesTo assess the treatment effect of TAVR versus SAVR on clinical outcomes to 3 years in patients stratified by chronic kidney disease (CKD) by retrospectively studying patients randomized to TAVR or SAVR.BackgroundThe impact of CKD on mid‐term outcomes of patients undergoing TAVR versus SAVR is unclear.MethodsPatients randomized to TAVR or SAVR in the CoreValve US Pivotal High Risk Trial were retrospectively stratified by eGFR: none/mild or moderate/severe CKD. To evaluate the impact of baseline CKD in TAVR patients only, all patients undergoing an attempted TAVR implant in the US Pivotal Trial and CAS were stratified by baseline eGFR into none/mild, moderate, and severe CKD. The primary endpoint was major adverse cardiovascular and renal events (MACRE), a composite of all‐cause mortality, myocardial infarction, stroke/TIA, and new requirement of dialysis.ResultsModerate/severe CKD was present in 62.7% and 60.7% of high‐risk patients randomized to TAVR or SAVR, respectively. Baseline characteristics were similar between TAVR and SAVR patients in both CKD subgroups, except for higher rates of diabetes and higher serum creatinine in SAVR patients. Among high‐risk patients with moderate/severe CKD, TAVR provided a lower 3‐year MACRE rate compared with SAVR: 42.1% vs. 51.0, P = .04. Of 3,733 extreme‐ and high‐risk TAVR patients, 39.9% had none/mild, 53.8% moderate, and 6.4% severe CKD. Worsening baseline CKD was associated with increased 3‐year MACRE rates [none/mild 51.5%, moderate 54.5%, severe 63.1%, P = .001].ConclusionsTAVR results in lower 3‐year MACRE versus SAVR in high‐risk patients with moderate/severe CKD. In patients undergoing TAVR, worsening CKD increases mid‐term mortality and MACRE. Randomized trials of TAVR vs. SAVR in patients with moderate‐severe CKD would help elucidate the best treatment for these complex patients.Trial RegistrationCoreValve US Pivotal Trial: NCT01240902.CoreValve Continued Access Study: NCT01531374.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148361/1/ccd27928_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148361/2/ccd27928.pd

Влияние добавок висмута на теплофизические и термодинамические свойства алюминиевого проводникового сплава E-AlMgSi (алдрей)

The economic feasibility of using aluminum as a conductive material is explained by the favorable ratio of its cost to the cost of copper. It is also important that the cost of aluminum for many years remains virtually unchanged.When using conductive aluminum alloys for the manufacture of thin wire, winding wire, etc. Certain difficulties may arise in connection with their insufficient strength and a small number of kinks before fracture. In recent years, aluminum alloys have been developed, which even in a soft state have strength characteristics that allow them to be used as a conductive material.One of the promising areas for the use of aluminum is the electrical industry. Conducting aluminum alloys of the E-AlMgSi type (Aldrey) are representatives of this group of alloys. The paper presents the results of a study of the temperature dependence of heat capacity, heat transfer coefficient, and thermodynamic functions of an aluminum alloy E-AlMgSi (Aldrey) with bismuth. Research conducted in the "cooling" mode.It was shown that the temperature capacity and the thermodynamic functions of the alloy E-AlMgSi (Aldrey) with bismuth increase with temperature, and the Gibbs energy decreases. Additives of bismuth up to 1 wt.% Reduce heat capacity, heat transfer coefficient, enthalpy and entropy of the initial alloy and increase the value of Gibbs energy.Экономическая целесообразность применения алюминия в качестве проводникового материала объясняется благоприятным соотношением его стоимости и стоимости меди. Немаловажным является и то, что стоимость алюминия в течение многих лет практически не меняется.При использовании проводниковых алюминиевых сплавов для изготовления тонкой проволоки, обмоточного провода и т.д. могут возникнуть определённые сложности в связи с их недостаточной прочностью и малым числом перегибов до разрушения. В последние годы разработаны алюминиевые сплавы, которые даже в мягком состоянии обладают прочностными характеристиками, позволяющими использовать их в качестве проводникового материала.Одним из перспективных направлений использования алюминия является электротехническая промышленность. Проводниковые алюминиевые сплавы типа E-AlMgSi (алдрей) являются представителями данной группы сплавов. В работе представлены результаты исследования температурной зависимости теплоемкости, коэффициента теплоотдачи и термодинамических функции алюминиевого сплава E-AlMgSi (алдрей) с висмутом. Исследования проведены в режиме «охлаждения».Показано, что от температуры теплоемкость и изменений термодинамический функции сплава E-AlMgSi (“алдрей”) с висмутом увеличиваются, а значение энергия Гиббса уменьшается. Добавки висмута до 1мас.% уменьшают теплоемкость, коэффициент теплоотдачи, энтальпию и энтропию исходного сплава и увеличивают величину энергии Гиббса

Functionalized Positive Nanoparticles Reduce Mucin Swelling and Dispersion

Multi-functionalized nanoparticles (NPs) have been extensively investigated for their potential in household and commercial products, and biomedical applications. Previous reports have confirmed the cellular nanotoxicity and adverse inflammatory effects on pulmonary systems induced by NPs. However, possible health hazards resulting from mucus rheological disturbances induced by NPs are underexplored. Accumulation of viscous, poorly dispersed, and less transportable mucus leading to improper mucus rheology and dysfunctional mucociliary clearance are typically found to associate with many respiratory diseases such as asthma, cystic fibrosis (CF), and COPD (Chronic Obstructive Pulmonary Disease). Whether functionalized NPs can alter mucus rheology and its operational mechanisms have not been resolved. Herein, we report that positively charged functionalized NPs can hinder mucin gel hydration and effectively induce mucin aggregation. The positively charged NPs can significantly reduce the rate of mucin matrix swelling by a maximum of 7.5 folds. These NPs significantly increase the size of aggregated mucin by approximately 30 times within 24 hrs. EGTA chelation of indigenous mucin crosslinkers (Ca2+ ions) was unable to effectively disperse NP-induced aggregated mucins. Our results have demonstrated that positively charged functionalized NPs can impede mucin gel swelling by crosslinking the matrix. This report also highlights the unexpected health risk of NP-induced change in mucus rheological properties resulting in possible mucociliary transport impairment on epithelial mucosa and related health problems. In addition, our data can serve as a prospective guideline for designing nanocarriers for airway drug delivery applications