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The application of a non-stationary regime of temperature modulation in metal oxide semiconductor sensor based on SnO2–Ag leads not only to a strongly increased sensor response, but also to a considerably improved sensor selectivity toward hydrogen sulfide. Selectivity with respect to other reducing gases (CO, NH3, H2) is about five orders of magnitude, enabling a correct selective determination of H2S in the presence of interfering gas components.

This work is an investigation of the properties of semiconductor materials based on metal oxides, their catalytic properties, and their application as gas sensors, which were shown to exhibit high sensitivity, stability, and selectivity to target gases. The aim of this work is the comparison of gas sensing properties of tin dioxide in the form of individual nanowires and nanopowders obtained by sol–gel synthesis. This comparison is necessary because the traditional synthesis procedures of small particle, metal oxide materials seem to be approaching their limit. Because of this, there is increasing interest in the fabrication of functional materials based on nanowires, i.e., quasi-one-dimensional objects. In this work, nanocrystalline tin dioxide samples with different morphology were synthesized. The gas-transport method was used for the fabrication of well-faceted wire-like crystals with diameters ranging between 15–100 nm. The sol–gel method allowed us to obtain fragile gels from powders with grain sizes of about 5 nm. By means of X-ray photoelectron spectroscopy (XPS) it was proven that the nanowires contain considerably smaller amounts of hydroxy groups compared to the nanopowders. This leads to a decrease in the parasitic sensitivity of the sensing materials to humidity. In addition, we demonstrated that the nanowires are characterized by a nearly single-crystalline structure, ensuring higher stability of the sensor response due to the unlikelihood of sample recrystallization. The results from the ammonia detection experiments showed that the ratio of the sensor response to the surface area exhibits similar values for both the individual nanowire and nanopowders-based sensor materials.

We have applied spark ablation technology for producing nanoparticles from platinum ingots (purity of 99.97 wt. %) as a feed material by using air as a carrier gas. A maximum production rate of about 400 mg/h was achieved with an energy per pulse of 0.5 J and a pulse repetition rate of 250 Hz. The synthesized nanomaterial, composed of an amorphous platinum oxide PtO (83 wt. %) and a crystalline metallic platinum (17 wt. %), was used for formulating functional colloidal ink. Annealing of the deposited ink at 750 &deg, C resulted in the formation of a polycrystalline material comprising 99.7 wt. % of platinum. To demonstrate the possibility of application of the formulated ink in printed electronics, we have patterned conductive lines and microheaters on alumina substrates and 20 &mu, m thick low-temperature co-fired ceramic (LTCC) membranes with the use of aerosol jet printing technology. The power consumption of microheaters fabricated on LTCC membranes was found to be about 140 mW at a temperature of the hot part of 500 &deg, C, thus allowing one to consider these structures as promising micro-hotplates for metal oxide semiconductor (MOS) gas sensors. The catalytic activity of the synthesized nanoparticles was demonstrated by measuring the resistance transients of the non-sintered microheaters upon exposure to 2500 ppm of hydrogen.

Analysis of electricity consumption by consumer groups in the Dmitrovsky district of the Orel region, Russian Federation shows that changes in the consumption structure takes place in the direction of a slight increase in the energy consumption by ‘other consumers’ whereas there is a decrease in the proportion of the households, industry and budget sector. The reduction in electricity consumption in the budget sector is associated with the closure of a number of budget organizations (primarily rural schools) and the transfer of others to a shorter work schedule. At the same time, there is no noticeable decrease in payments for electricity by this group in the whole district. A slight increase in consumption by ‘other consumers’ is associated with the transfer of part of population to homeowners’ association and cooperatives. The reduction in electricity consumption by industry is also associated with the closure of a number of enterprises and with a change in the load of existing ones. Increased costs for electricity bill, even while reducing its consumption in real terms across all groups of consumers, allows us to conclude that the effort to reduce the tariff burden for all groups of consumers have not yielded significant results.

Large-amplitude fluctuations of the solar wind magnetic field can scatter energetic ions. One of the main contributions to these fluctuations is provided by solar wind discontinuities, i.e., rapid rotations of the magnetic field. This study shows that the internal configuration of such discontinuities plays a crucial role in energetic ion scattering in pitch angles. Kinetic-scale discontinuities accomplish very fast ion pitch-angle scattering. The main mechanism of such pitch-angle scattering is the adiabatic invariant destruction due to separatrix crossings in the phase space. We demonstrate that efficiency of this scattering does not depend on the magnetic field component across the discontinuity surface, i.e., both rotational and almost tangential discontinuities scatter energetic ions with the same efficiency. We also examine how the strong scattering effect depends on the deviations of the discontinuity magnetic field from the force-free one.

A combination of low limit of detection, low power consumption, and portability makes organic field-effect transistor (OFET) chemical sensors promising for various applications in the areas of indu...

The article analyzes the prospects for the evolution of the odious terrorist group of modern times, «al-Qaeda». This topic is relevant, since the ongoing conflicts in the middle East, Africa and Asia continue to serve as an «ideal» environment for the development of radical groups and ideologies. Based on a detailed study of the history of the formation of this organization, its ideology, goals, objectives and strategy, the authors consider the possibility of «al-Qaeda» becoming the dominant force in the global extremist movement in the coming years. The article examines the main stages of activity of this group, presents the results of a comparative analysis of the tactics of «al-Qaeda» and its main competitor «ISIS». It is concluded that the strategic goal of «al-Qaeda» is to strengthen unity among foreign fighters of the global extremist movement. By engaging in some conflicts that are both fundamental and highly symbolic, «al-Qaeda» can further strengthen its image as the «true» vanguard of Islamist insurgents. The article focuses on the relationship between «al-Qaeda» and its affiliates in Iraq, Algeria, Yemen, and South Asia. The authors ' conclusions are based on the analysis of publications and speeches in the media space of the radical leader, A. al-Zawahiri. The authors conclude that modern «al-Qaeda» is a decentralized, networked transnational terrorist organization. The conclusion is made about the possibility of «al-Qaeda» entering a new phase of activity, which will include strengthening territorial control, expanding recruitment and high-profile terrorist attacks around the world.

The deployment of armed forces of the US and its allies on the territory of Saudi Arabia in 1990 and their war against Iraq in 1991 strengthened American dominance in the region and at the same time revealed previously concealed internal contradictions in Saudi society. A divide between the pro-monarchy and anti-Saudi movements became evident. It resulted in an ideological struggle between former allies - the Wahhabis and the Muslim Brothers - inside and outside the kingdom. The Islamist discourse of the Brothers and Sahwa movement (a sort of hybrid of Wahhabism and Muslim Brotherhood ideology) manifested itself in questioning the legitimacy of the Saudi rule and promoting a general anti-American attitude. Those contradictions gave birth to Al-Qaeda, which declared a global jihad against the West and the monarchies of the Persian Gulf. The September 11, 2001 attacks in New York gave Washington an excuse to invade Afghanistan and then, after a successful blitzkrieg there, encouraged the US to begin a war in Iraq under the fake pretext of Iraqi plans to develop all kinds of weapons of mass destruction. Consequences for the Saudi government included the strengthening of Sunni - Shiite contradictions inside the kingdom and in the region as well as an explosion of terrorism inside Saudi Arabia. After the establishment of the Shiite majority government in Iraq, the Sunni - Shiite contradictions have turned into a cold war between Saudi Arabia and Iran. This situation aggravated the instability in the Middle East and precluded potential compromises.

This paper is devoted to the development of a numerical approach that allows quick detection of the conditions favorable for the beginning of noticeable vibrations during drilling. The main novelty of the proposed approach lies in taking into account the deviations of the assembled compliant parts during non-stationary contact analysis by means of variation simulation. The approaches to stationary analysis of assembly quality are expanded and generalized for modeling such non-stationary effects as vibration and resonance. The numerical procedure is based on modeling the stress–strain state of the assembled structures by solving the corresponding transient contact problem. The use of Guyan reduction, the node-to-node contact model and the application of the generalized α method allow the reformulation of the contact problem in terms of a series of quadratic programming problems. The algorithm is thoroughly tested and validated with commercial software. The efficiency of the developed numerical procedure is illustrated by analysis of the test joints of two aircraft panels. The unsteady process of drilling the panels with periodic drilling force was simulated. The influence of deviations in the shape of the parts on the non-stationary interlayer gap was modeled by setting different initial gaps between parts. It is shown that the oscillation amplitudes of the interlayer gap depend on the initial gaps and do not correlate with the mean value of the stationary residual gap. Thus, non-stationary analysis provides new information about the quality of the assembly process, and it should be applied if the assembly process includes periodic impact on the assembled parts.

This paper is dedicated to the issues of designing of outriggers for avoidance of vehicle tilting during its stability tests. An analysis of existing types of outriggers was done by authors as well as legislative requirements on them. The reliable and well-timed operation of outriggers largely depends on the height of their positioning on a vehicle. In order to determine this important parameter a special methodic of determining the tipping angle of the vehicle with the use of computer-aided design (CAD) was composed by authors. The article also contains some main principles of strength analysis of the structure a very important part of which became the necessity of determination of coefficient of friction between the outrigger sliders and the supporting surface. This coefficient has a direct impact on the value of transverse forces appearing at the ends of outrigger beams.

The tire model validity factors are listed and discussed when using tires in complex multi-mass vehicle models. Complex vehicle system models are used to estimate (to forecast) their handling and stability properties (including Electronic Stability Control (ESC) performance). It should be as less as possible discrepancy between vehicle virtual computational and experimental tests results. The objective forces to create more complex vehicle models. A tire is known to be the one of the most significant elements in the model and to influence considerably on vehicle handling and stability factors transmitting all road reactions. The paper describes factors to be able to get influence on the PAC2002 pneumatic tire model validity when simulating it in MSC.ADAMS/Car Software. The tire model creating begins by conducting studies of rolling tire characteristics. The studies are examined on tire benches. Conducting experimental studies there are the set of factors to be able to bring a measurement error into study results. The analysis of various literary sources has permitted to choose three basic factors to be able to get influenced on tire model and all the vehicle model validity. Among these factors there are following: tire pressure, tire temperature и tire tread wear. The most significant of these factors is the tire pressure. For providing required study accuracy it needs to apply tight restrictions on each factor changing range influencing on rolling tire characteristics. The ranges are to be determined for each certain tire model by using study results.

The kinematic scheme of a two-stream transmission is considered, which makes it possible to implement the principle of using two engines (including those using different physical principles and having different energy characteristics) and to implement the idea of design a hybrid power plant, including one adapted for operation on a driverless ship. The result of the research is the structural diagram of the transmission, the kinematic diagram of the summing gear in its composition and proposals for the implementation of the main units of the summing gear. The gearbox allows for smooth connection or disconnection of selected motors to the payload. The considered power plant combines an internal combustion engine and a traction motor. The main benefit is increased reliability through redundant motors. Improvements in efficiency are expected by ensuring consistent engine performance. The composition, the kinematic diagram, the principle of the transmission are proposed. The equations describing the kinematic and force relations in the summing gear are considered. The used method of kinematic and force analysis has been tested in the machine-building industry in relation to planetary gears as part of highly loaded transmissions of wheeled and tracked vehicles. References are given to technical solutions that make it possible to implement the proposed transmission based on the technological capabilities mastered by Russian manufacturers. The proposed scheme seems to be promising for use on ships for various purposes, including military boats, in the power plant of which a gas turbine engine is used.

Two dimensional (2D) MXene decorated by the SnO2 nanoparticles has been successfully synthesized by the hydrothermal method. The formed MXene/SnO2 heterojunction based chemirestistive-type sensors exhibit an excellent sensitivity and selectivity to different concentrations of NH3 from 0.5 to 100 ppm at room temperature. The enhanced sensing properties can be attributed to two major factors. On one hand, 2D MXene provides a matrix which has a unique, selective adsorption ability to ammonia and good conductivity that makes the room-temperature sensing of the heterojunction based sensor feasible. On the other hand, the difference in the Fermi level of the 2D MXene and SnO2 drives the charge transfer at the interface of the heterojunctions enriching the electrons on the surface region of SnO2 and consequently enhancing the sensitivity. Furthermore, a wireless sensor made from an inductor-capacitor (LC) antenna and the as-synthesized MXene/SnO2 heterojunctions fabricated by the low-temperature-cofired ceramic technique (LTCC) was preliminary investigated. The wireless sensor shows a even faster response/recovery speeds (

The chapter analyzes the power supply restoration time. The analysis shows that this time consists of the time for obtaining information about failure, the time of information recognition about failure, the damage repair time and the time of connection and disconnection harmonization. Each of them, in turn, is also considered in more detail that allows identifying reserves to reduce the power supply outage time. The chapter proposes reducing the power supply restoration time by going to the monitoring system combination of both operating modes and technical condition of power networks. Based on the study results, there are methods allowing to reduce the power supply outage time of rural consumers by means of automating rural electrical networks and improving the operating mode monitoring of power supply systems. The chapter also suggests a set of devices that allows to implement the proposed methods.

We prepared platinum nanoparticle ink usable for the fabrication of MEMS microheatersof high-temperature gas sensors and thermoresistors operating up to 450 °C and present somepreliminary results on the application of the ink in sensor microheater manufacturing. The inkconsists of platinum particles (3⁻8 nm) suspended in ethylene glycol solution of polyvinylpyrrolidone.The ink is usable in both InkJet and AerosolJet printers. The annealing at temperature of about 600 °Cleads to the formation of uniform microheater structure. The experiments on microheater agingconfirm the stability of the printed microstructure at 450 °C for at least one year of operation. Thesubstrates used for printing were thin alumina and LTCC ceramics with thickness of 12⁻20 μm.

The perspective catalysts usable for the fabrication of thermocatalytic gas sensors were studied. The analysis of CO oxidation kinetics by Pd decorated Al2O3, ZSM-5, SnO2, CeO2/ZrO2 and some other carriers of catalysts showed that the application of these catalysts leads to the ambiguity of sensor response (light-off effect). It was demonstrated that a catalyst based on CeO2/ZrO2 carrier could be used for the fabrication of sensors characterized by the univocal correspondence between CO concentration and sensor response. The developed model of the CO oxidation on all Pd catalysts with inert carrier enabled the description of the CO oxidation using a single value of activation energy.

The online control of natural gas quality is important for customers, because for them the important value is calorific value of consumed gas, but not its volume. The application of thermoconductometric sensor gives simple possibility to fabricate imbedded intellectual plug-and-play device for this control. The ceramic MEMS sensor based on a combination of this ceramic LTCC membrane and aerosol jet printed platinum microheater was used as a sensing element of this unit. The electronic unit controlling the sensor was designed to stabilize the temperature of the microheater and to measure power necessary to maintain this temperature at different concentrations of N2and CO2 in natural gas. The application of this unit enables the measurement of admixtures of nitrogen and CO2 with detection limit of about 1 vol. % sufficient for the application in gas meter instruments.

We demonstrated the possibility of selective detection of hydrogen, ethanol, hydrogen sulfide, carbon monoxide, methane and ammonia gas using metal oxide gas sensor operating in non-stationary thermal regime. This non-stationary regime consists in fast heating of the sensing layer to high temperature followed by temperature stabilization at lower temperature. The analysis of the shape of the curve describing the sensor resistance as a function of time during this measurement cycle enables the quantitative analysis of gas mixture. The investigation of kinetics of the process in non-stationary regime permits to understand the mechanism of the processes on the surface of sensing material.

In this work gas sensing properties of Langmuir-Schaefer monolayer organic field-effect transistors (LS OFETs) prepared from organosilicon derivative of [1]benzothieno[3,2-b][1]-benzothiophene (BTBT) have been investigated. The monolayer has been deposited using Langmuir-Schaefer method, which results in a uniform low-defect monolayer with excellent electrical performance, hole mobility up to 7 × 10−2 cm2 V−1 s−1, the threshold voltage around 0 V and on-off ratio of 104. Developed sensors demonstrate a long-term stability of a half-year storage under ambient conditions. Preliminary investigations demonstrated that the LS OFETs give instantaneous response on ammonia and hydrogen sulfide at low concentrations. The results reported open new perspectives for the OFET-based gas-sensing technology.

Detection of dissolved methane and volatile hydrocarbons in water is a problem met inleakage localization during exploitation of underwater pipelines, oil and oil product spill over watersurface, geological exploration work for the localization of oil and gas fields under water, etc. Thisproblem can be solved by the application of detection system based on tubular selective membranepermeable for volatile organics and impenetrable for liquid water. Carrier gas (air) flowing throughthis tube is saturated with dissolved gas and then gas concentration is measured usingsemiconductor or other gas sensor. The system prototype was tested under laboratory conditionsand demonstrated low limit of gas detection (~20 ppb by mass of dissolved methane in water) andshort response time (~10 s).