Estimation of the power of mechanical losses in the engine, transmission and wheels of car on the stand with running drums

The efficiency of a car is considered through the amount of energy loss spent on transmission from the engine to the driving wheels of the car. Analytical and experimental methods for assessing mechanical losses are analyzed. The advantages and disadvantages of road and bench tests of a car in free run modes are indicated. A description of the diagnostic equipment - a stand with running drums, used to simulate the movement of a car in laboratory conditions is given. The components of the necessary measuring equipment for recording the speed and torque on the wheels of a car are considered. The list of primary measuring sensors and main transducers is indicated, which transmit information to the computer. The results of the car run-out on the stand are given: the change in the instantaneous speed from time to time. The primary assessment of the regression model is made and the values of the coefficients are obtained by the method of least squares of deviations of the vehicle speed. A mathematical model for the subsequent processing of experimental data has been developed. The purpose of mathematical modeling is to separate mechanical losses by power units separately for the engine, transmission and car wheels. An assessment was made of the amount of energy losses in the stand itself with running drums. The characteristic of the stand has been obtained, which must be taken into account in the measurement procedure. The results of experimental studies for the GAZ-31029 car are presented. The results of the influence of the technical condition of transmission units and vehicle wheels on the value of the power of mechanical losses are presented. Car tire pressure studies have been conducted. The graphical dependences of the power of mechanical losses depending on the speed of the car are obtained. Recommendations have been developed for diagnosing the general condition of the vehicle by the amount of mechanical losses at the stand with running drums. The ways of further improvement of the method are given. The main conclusions based on the research results are formulated.

СУТОЧНАЯ МНОГОКАНАЛЬНАЯ РН-ИМПЕДАНСОМЕТРИЯ ПИЩЕВОДА В ДИАГНОСТИКЕ ГАСТРОЭЗОФАГЕАЛЬНОЙ РЕФЛЮКСНОЙ БОЛЕЗНИ (КЛИНИЧЕСКИЕ СЛУЧАИ)

Background. Gastroesophageal reflux disease (GERD) is an urgent problem of modern gastroenterology as well as the most common pathology of the upper gastrointestinal tract; it is a chronic disease that significantly reduces the patient's quality of life, increases the risk of developing Barrett's esophagus and esophageal adenocarcinoma. Objective. To assess the potentials of multichannel intraluminal pH impedance monitoring in the diagnosis of esophageal diseases. Material and methods. In 3 patients with clinical and endoscopic signs of GERD esophageal multichannel intraluminal pH-impedance monitoring was performed using the diagnostic equipment Digitrapper pH-Z from Given Imaging (USA). Results. 24-hour esophageal pH monitoring enabled to verify the diagnosis of GERD, to reveal a hypersensitive esophagus and manifestations of nocturnal acid breakthrough. Conclusions. Multichannel intraluminal pH-impedance monitoring is the "gold standard" for the diagnosis of esophageal diseases; it significantly expands opportunities of gastroenterologists in the treatment of GERD.

Omicron and Delta Variant of SARS-CoV-2: A Comparative Computational Study of Spike protein

Emerging SARS-CoV-2 variants, especially those of concern, may have an impact on the virus’s transmissibility and pathogenicity, as well as diagnostic equipment performance and vaccine effectiveness. Even though the SARS-CoV-2 Delta variant (B.1.617.2) emerged during India’s second wave of infections, Delta variants have grown dominant internationally and are still evolving. On November 26, 2021, WHO identified the variant B.1.1.529 as a variant of concern, naming it Omicron, based on evidence that Omicron contains numerous mutations that may influence its behaviour. However, the mode of transmission and severity of the Omicron variant remains unknown. We used computational studies to examine the Delta and Omicron variants in this work and found that the Omicron variant had a higher affinity for human ACE2 than the Delta variant due to a significant number of mutations in the SARS-CoV-2 receptor binding domain, indicating a higher potential for transmission. Based on docking studies, the Q493R, N501Y, S371L, S373P, S375F, Q498R, and T478K mutations contribute significantly to high binding affinity with human ACE2. In comparison to the Delta variant, both the entire spike protein and the RBD in Omicron include a high proportion of hydrophobic amino acids such as leucine and phenylalanine. These amino acids are located within the protein’s core and are required for structural stability. Omicron has a higher percentage of alpha-helix structure than the Delta variant in both whole spike protein and RBD, indicating that it has a more stable structure. We observed a disorder-order transition in the Omicron variant between spike protein RBD regions 468-473, and it may be significant in the influence of disordered residues/regions on spike protein stability and binding to ACE2. A future study might investigate the epidemiological and biological consequences of the Omicron variant.

Monolithic transistor switch for microwave radiometry

Modern medical microwave diagnostic equipment requires the application of solutions related to the compactness of the developed devices and high performance. Ensuring these requirements is possible by using a modern semiconductor component base based on A3B5 compounds. One of the promising materials for this purpose is gallium nitride. The paper presents the design and manufacturing technology of one of the main control elements of the microwave signal in microwave radiothermometer - monolithic AlGaN/GaN/SiC HEMT SPDT transistor switch.

Failure Localization Techniques for 7nm & 16nm Process Nodes in Monolithic & 2.5D SSIT Package Technology Using OBIRCH, LVP and Advance Die Thinning Method

High performance IC's have driven the semiconductor industry towards the sub-nanometer technology nodes for several years. At 16nm and beyond, the spatial resolution and sensitivity of some diagnostic equipment used for failure analysis have reached certain limitations. The accuracy of isolating a faulty signal in a tightly packed group of transistors in a die becomes more challenging. However, with the improvement of SIL (Solid Immersion Lens) based lens technology with higher N.A. (Numeric Aperture), combined with precision die thinning process, allowed some very promising results. This paper demonstrates successful diagnostic techniques utilizing the SIL lens and a variety of die thinning preparation techniques on 7nm and 16nm process nodes in both monolithic and 2.5D SSIT (Stacked Silicon Interconnect Technology) packages.

RESEARCH AND DIAGNOSTICS FOR THE LABORATORY OF PRESSURE RESISTANT SENSORS

The use of the sensors shortens the service life, wears out and reduces their accuracy due to operation. For sensors with a susceptibility to inaccuracy, it is possible to create a sensor-device-software diagnostic set. Such a scheme of configuration should be able to provide autonomic diagnostic, calibration, evaluation and also recalibration of the sensor. The diagnostic equipment could also have a shock test function in order to intentionally and faster reduce the service life and thus test the correctly set parameters of the diagnostic algorithm in laboratory conditions. The diagnostic device is a specialized technical system that provides conditions for the future potential of the testing development, knowledge and experience. According to the design, it can be modularly enriched with new parts, fixtures and systems to provide a more diverse range of options. There would be space for exploring the possibilities of new types of sensors, their comparison, as well as full-fledged automation of the complex diagnostic process.

DIAGNOSIS OF FUEL EQUIPMENT OF DIESEL ENGINE BY REMOVING VYBRO INDICATORS OF FUEL SUPPLY

Modern cars are increasingly equipped with control and diagnostic equipment. These methods are used to optimize the working process in the engine, improve traffic safety and simplify operation and maintenance. You can adjust the chip to your liking, adjust the "performance" of the engine, because comfortable driving conditions give us a lot of pleasure. The current control of technical conditions is carried out by the onboard system of self-diagnostics, which is an integral part of the controller. Problems that occur are signaled visually and stored in electronic memory. The full list of actual settings of codes of self-diagnostics and parameters of working process is carried out on HUNDRED with automobile indicators of brand. The problem is determined only by connecting a tester or scanner to a special diagnostic connector available in the car. However, there are often complaints about objective and comprehensive examinations. Misdiagnosis of "standards" with obvious signs of external problems is often given for many reasons. First of all, the use of information is limited electrical signals. In fact, the state of the circuit of sensors and actuators of engine automation is determined. Degradation of complex structures is usually based on the "domino principle": one local problem leads to another, another to a third, etc., which leads to the complete failure of the whole device. Problems with electricity may not be the cause but the consequences of other problems, including non-electrical causes. For example, the "ringing" of the piston fingers may indicate early inflammation and wear of the relevant components. The instability of the spark discharge in the spark plug may be the result of decompression of the working volume of the cylinder or improper preparation of the working mixture. The problem of the intake manifold or contamination of the fuel injector is usually recognized by the self-diagnostic system as a fault of the lambda detector. The list of such ambiguities can be expanded. When it is necessary to "restore" the accident of "decent age", branded diagnostic equipment may be useless.

Control of spectral characteristics of the medical accelerator on the basis of comparison of mass weaking coefficients of different materials

Background. Radiation protection of patients undergoing radiation therapy using linear electron accelerators is based on ensuring the constancy of the equipment parameters set during commissioning. Therefore, studying the possibility of operational assessment of the spectrum characteristics consistency of the generated bremsstrahlung is a priority along with standard dosimetric parameter control procedures. Primarily, this refers to specifying the average measured energy of bremsstrahlung which provides an impartial assessment of the constancy of the whole wave path of the accelerator. However, there is no special diagnostic equipment to determine this parameter. At the same time, the literature data represent a growing interest in the use of CdTe sensors for the analysis of high-energy radiation, including the ones in medical accelerators. Purpose – developing and testing special diagnostic equipment based on semiconductor CdTe sensors, which would implement the assessment of the average measured energy of bremsstrahlung of the medical accelerator 6 MeV via comparing the mass attenuation coefficients in lead and aluminum. Materials and Methods. The paper deals with experimental evaluation of the Varian Clinac 600C linear accelerator (USA) spectrum characteristics carried out at Radiation Oncology Department of State Organization «Grigoriev Institute for Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine» via determining the average measured energy of bremsstrahlung. The assessment of the average measured energy of the bremsstrahlung of the accelerator was performed based on comparing two mass attenuation coefficients of radiation with materials having significantly different atomic numbers, i.e. Al and Pb. The assessment of the mass attenuation coefficients was performed on the basis of measuring the average amplitudes of CdTe signals of the sensor, operating in the pulse mode in conjunction with a 16-bit ADC. Pulses of bremsstrahlung from the linear accelerator were recorded by a peak detector for 10 seconds of measurement by the hardware-software complex at 400 monitor units by CdTe sensor with aluminum and lead absorber. The study was performed at a distance of «source-surface» 100 cm with an area of the irradiation field of 20x20 cm. The spectral energy profile of the generated field of bremsstrahlung was studied. Results. The developed equipment was tested by CdTe sensor, which was created taking into account the energy sensitivity of the sensor itself as well as the spectraltemporal characteristics of the pulsed radiation of the accelerator. The approach dealing with assessing the average measured energy of bremsstrahlung of the linear electron accelerator, based on the dependence of the attenuation of radiation by the absorber layer on the radiation energy, has been experimentally confirmed. The theoretical dependence of the average measured energy of bremsstrahlung of the linear accelerator on the ratio of the mass attenuation coefficients of lead and aluminum has been obtained. The energy range from 0.1 to 6 MeV corresponds to the ratio of mass absorption coefficients of lead to aluminum, varying nonlinearly from 33.8 to 1.639. The average measured energy of the linear accelerator of 0.8 MeV corresponds to a mass coefficient ratio of about 1.23 for these materials. The assessed absolute error (from the set value during commissioning the linear accelerator) of the specified measured average energy of bremsstrahlung is up to 12.5% (0.72 MeV), corresponding to the ratio of mass attenuation coefficients – 1.340. Conclusions. The special diagnostic equipment for recording the spectrum characteristics of the Varian Clinac 600C linear accelerator (USA) based on semiconductor CdTe sensors, which along with 16-bit ADC make it possible to estimate the average measured energy of bremsstrahlung via comparing mass attenuation coefficients in Al and Pb has been substantiated and reduced to practice. The assessment of mass attenuation coefficients is carried out based on measuring the average amplitudes of pulses of СdTe sensors operating in a pulse mode.