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The article considers issues of researchers’ work assessment of sectoral research institutes in the Russian Federation. The authors investigate the advantages and disadvantages of the existing system of scientometric indicators with relation to the researchers’ publication activity increase. Practical solutions are proposed to harmonize the internal and external motivation of the researchers’ work of the sectoral research institute in order to ensure the effectiveness of their scientific activities, the implementation of key indicators of the effectiveness of scientific work and to promote the economic and innovative effect of the institute activities. The authors proposed a conceptual system for stimulating the work of researchers through authorship in scientific publications and evaluated its effectiveness. The scientific novelty lies in the development of a system of incentives for authorship in scientific publications to employees of the Railway Research Institute. The practical significance of the study lies in the possibility of applying the incentive system in many sectors of the modern economy.

Introduction. The tasks of increasing energy saving in heating systems for passenger cars of diesel trains are currently relevant. As an alternative source of energy for these systems, the possibility of using the waste heat of the diesel locomotive engine is analysed.Materials and methods. The article provides an analysis of the engine waste heat sources, cooling water and exhaust gases. A schematic diagram of exhaust gas heat exchanger for its use in the heating system of passenger cars has been deve loped. As a possible heat-exchange surface of the waste heat exchanger, plate-ribbed, coiled and tube surfaces with longitudinal boundary layer turbulators are proposed. The required area of this surface for the maximum power of the heating system for a passenger train is determined.Results. The article shows the possibility of using engine exhaust heat in the heating system of a 15-car passenger train without involving third-party energy sources.Discussion and conclusion. The obtained results demonstrate a sufficient potential for increasing the efficiency of using the diesel engine fuel energy when utilising its waste heat for the heating system of passenger cars. The selection of a waste heat exchanger is justified based on a performance of 50 % of the peak load on the heating system at the middle position of the controller.

The article is devoted to the assessment of the effectiveness of tax regulation in the field of foreign economic activity of the Donetsk People’s Republic. The article reveals the essence of the taxation process in the field of foreign trade, its principles, methods and main tools.

Adoption by Russia of the Kigali Amendment to the Montreal Protocol on substances that deplete the ozone layer posed a very difficult task for consumers of artificial cold, including rail transport, to find an acceptable alternative to the R134a freon and mixtures based on it, which is being phased out. Considering that there are no equivalent alternatives to these substances on the market, it was proposed to consider the use of widely known and previously used working fluids in climate technology, based on the positive experience of the European Union (EU) countries. The article analyzes the reasons for the bans on the use of hydrofluorocarbons, presents the mechanism for the legal use of refrigerants that are safe for humans and nature in the EU and a version of the roadmap for converting the climatic units of the Russian Railways holding to R22 freon and other types of fluorocarbons within the framework of the Kigali Amendment.

Maintaining optimal parameters of the microclimate in the car along the route is the most important requirement for the passenger’s travel. In the 1st class passenger cars, maintaining optimal microclimate parameters is achieved through the operation of the air conditioning system, which provides individual regulation of the air temperature in each compartment. Individual air temperature control systems used in air conditioning systems are divided into two groups: active and passive.The article proposes for consideration a combined active-passive system with a separate air supply with a lower and higher temperature compared to the temperature maintained in the compartment and the installation of individual induction terminals, which makes it possible to increase the efficiency of individual regulation of air parameters in the compartment.To assess the uniformity of temperature distribution and air flow rate over the car volume with the proposed control scheme, a three-dimensional modeling of the distribution of these parameters in the compartment was carried out on the basis of Autodesk CFD software.The given simulation results indicate the uniformity of temperature and air flow rate distribution over the compartment volume, which makes it possible to characterize the proposed system as sufficiently energy efficient, easy to operate and reliable in operation.

Delivery of perishable freights in proper quality essentially depends on the correct choice of a special vehicle and the correct calculation of the delivery time. According to the requirements of the Rules for the transportation of perishable freights by rail, all special vehicles by January 1, 2022 must obtain certificates of compliance with the standards established by the Agreement on the International Transportation of Perishable Foodstuffs and on special vehicles intended for these transports. This requirement applies to special vehicles used both in international traffic and for transport of perishable freights within the country. The article presents a brief classification of special vehicles used for the transportation of perishable freights. Formulas are given that allow calculating duration of transportation of such freights and average temperature of the outside air along the entire route. Procedure for choosing a special vehicle for the already known duration of freight transportation has been developed. It is concluded that the procedure proposed by the authors allows choosing the optimal special vehicle for the transportation of perishable freights. Using this sequence of calculations makes it possible to take into account the maximum number of external factors that affect the duration of transportation.

Alternative energy sources, mostly related to “green” energy, are one of the promising trends in the development of energy generation, including for the global railway sector. This is due, firstly, to its desire to preserve its environmental advantages by reducing carbon dioxide emissions into the environment and increasing energy efficiency, and secondly, to a reduction in the use of such sources as oil and coal as fuel resources in the coming decades.In a world where 95 % of motorized vehicles use oil as fuel, the greenhouse gas emissions per passenger-kilometer for rail transport are five times less than for road transport and 20 times less than for air transport. Therefore, one of the key tasks in the development of railway transport is the creation of high-speed highways that will serve as an alternative to road and air communications over short distances.In addition to the well-known alternative energy technologies, the railway transport traditionally conducts scientific research to improve energy-saving technologies, which include the use of excess recuperation energy when rolling stock braking.Also, projects for the use of renewable energy sources — heat pump installations — have proved their effectiveness in railway transport: heating switches from the ground, use of heat from compressors of hill complexes to heat electrical centralization posts and heat transformers of traction substations for its own needs.The role of alternative energy sources in railway transport is constantly growing. The efficiency of using alternative energy sources at the Russian Railways is largely determined by a scientific approach that allows, based on own experience or experience in introducing innovations in related industries, to determine the place, time and degree of their implementation, taking into account technical and technological features of production processes inherent in a particular structural unit companies. Among the innovative technical solutions in railway transport, the most priority ones are solutions aimed at the development of high-speed lines, recuperation systems, as well as heat pump technologies.

Satisfying the needs of the population in the delivery of perishable freight of good quality largely depends on the stable operation of specialized vehicles and the accuracy of calculating the deadline for transporting freight to the consumer. The main value used to calculate the deadline for the transportation of perishable freight by rail is the heat transfer coefficient of the body of an insulated car or container. The accuracy of estimating this value is especially important when using isothermal cars or containers that are not equipped with cooling or heating systems as specialized vehicles. In this paper authors assess the influence of some external factors on the value of the heat transfer coefficient of the body of an isothermal vehicle. The change in the heat transfer coefficient due to the influence of the speed of the isothermal vehicle and insolation is taken into account. The heat transfer coefficients from the internal and external building envelopes to the ambient air for the standing car and during its movement are determined to assess the change in the heat transfer coefficient from the criterion dependencies. Taking into account real external factors, in particular outdoor temperature, humidity, train speed, significantly affects the heat transfer coefficient of the body of an isothermal vehicle, the value was determined in stationary conditions of the workshop and underlying the calculation of the maximum permissible terms for the transportation of perishable freights. This value is excellent from the actual value. As a result of the calculations, a discrepancy of the value of the deadline for the transportation of perishable freights in comparison with the current method is 3–10 %.Changes to the existing methodology will reduce the risk of delivery of perishable freight of inadequate quality due to incorrectly calculated deadlines for transportation.

Passenger rolling stock is operated in various climatic conditions, calculated outside temperature can vary from -40 to +40 °С. The microclimate parameters permissible for a long stay of people (the longest route is about 6 days) are achieved by installing ventilation, air conditioning and heating systems. Currently, more and more attention is being paid to the safety and comfort of passengers, and the urgent task is to create a climate system that ensures that the air environment in the premises of passenger rolling stock is up to date with all requirements. To ensure safe parameters of the car air environment, it is necessary to increase the influx of outdoor air to 20-35 m3/h per person, which allows achieving a CO2 content of 1000 ppm. It should be taken into account that an increase in the flow of external air and its conditioning leads to an increase in the cost of electricity (in order to fulfill the requirement for the content of CO2, an increase in the power of the heaters by 1.5-2 times is required), and therefore, the cost of transportation. Comparison of sources of additional energy, the use of which can increase the flow of external air into the car with minimal additional loads on the power supply system, showed the greatest efficiency of the installation with a heat pump that uses the heat of the exhaust air to heat the supply air in combination with maintaining air back-up for protection against dust. Proposed technical solution allows to increase the level of comfort in passenger cars with minimal energy costs for air processing and equipment dimensions. The problem of increased hydraulic resistance of the installation is solved by using a beam of transversely streamlined pipes with longitudinal turbulators of a hydraulic boundary layer as the heat exchange surface of the evaporator of the heat pump. This surface will allow to develop a heat exchanger with minimal resistance and thereby get away from the need for forced traction, limiting to a minimum back pressure of 15 Pa.

The main parameter determined in heat engineering tests of heat insulated cars superstructures or the locomotive operator’s cabs is the heat transfer coeffi cient К. The study introduces automated analysis technology for the heat transfer coeffi cient К of enclosure structures of the heat insulated transport means using a remote server. The underlying method provides coeffi cient K of the heat insulated transport means without additional work and time loss for complicated calculations. Personnel of test laboratories involved in heat engineering tests of vehicles possess tools for remotely calculating К, from any point in the world with internet access. To obtain К three controlled parameters measured during the heat engineering tests for 5.5 h including: the difference of the inside and outside temperature of the test object superstructure, total power of the electric heaters and geometric area of the heat transfer surface are sent to the server, after which the user promptly receives the calculated К. The economic effect of introducing the proposed technology for vehicle manufacture is the absence of required tests conducted at the test center; for an operating company — a signifi cant reduction of the idle time of the vehicle at the test center directly affects the loss of profi t. The proposed technology expands the area of operation of the test centers, while calculated К values are offi cially input into the data sheet of the vehicle.

When conducting thermal tests, the purpose of which is to determine the heat transfer coefficient of the body of an isothermal car K, the study of measurement errors affecting the accuracy of the obtained value plays an important role. The results of such experiments may contain various measurement errors that can introduce significant deviations into the resulting values of the desired coefficient. Obtaining accurate results when conducting this kind of experiments is impossible without a preliminary study of the causes that affect the final result. The article presents the types of measurement errors that affect the accuracy of determining the heat transfer coefficient of the body of an isothermal car when conducting thermal tests. It was noted that the magnitude of labor costs and energy losses during the further operation of this body significantly depends on the accuracy of the value of this coefficient. It was emphasized that one of the main types of random errors arising from measurements and compliance with the established procedure for conducting typical thermal tests is a voltage drop (“slump”) in the electrical network, leading to significant errors in the calculations of the heat transfer coefficient of the isothermal car body. The values of this coefficient are presented, which were obtained as a result of heat engineering tests performed using the equilibrium mode method and the express method. It is shown that the use of the express method to determine the heat transfer coefficient of the bodies of isothermal cars reduces the risk of random errors due to the minimum experiment duration (from 5.5 h), allows to obtain exact values of the desired coefficient (with an error not higher than 3 % of its value of long-term equilibrium method) and use this data for practical purposes.

The article shows the structure of the computer program “Express estimation system of the heat transfer coefficient for the vehicle”. The performance sequence of the automated calculation for determining the heat transfer coefficient ( K ) is described on the example of the refrigerator car body with the use of the data obtained during the accelerated thermal engineering tests. The advantages of the announced program are shown, consisting in a substantial reduction in the duration of testing, excluding the influence of the human factor when performing calculations and reducing the costs of organizing documentation flow. It was noted that for the operators of isothermal vehicles (ITV) the formation of an automated database with the calculated values results of K allows not only to monitor the dynamics of their changes during the ITV operations, but also with sufficient accuracy to predict the time of reaching the critical values of K , after which the regular energy installations will work with a significant expenditure of fuel and energy resources. The results of the expected economic efficiency in determining K by the accelerated method are presented; its value for the main types of ITV operating in the JSC “RZD” will be at least 14.0 billion rubles.

The article analyzes the heat exchange processes the thermal imaging method using a thermal imaging device. An occurring in the body of an isothermal vehicle when determining algorithm for determining the heat transfer coefficient is proposed, the heat transfer coefficient K by the internal heating method. which makes it possible to calculate its value with an accuracy not The differences are shown in the values of the heat transfer coef-exceeding 5 %, which is regulated by a number of international ficients obtained by the equilibrium internal heating method and normative documents, while reducing the duration of the experiment by at least 6 times. The study gives comparative experimental data and results of calculating the unknown values of K for bodies of isothermal vehicles obtained by the equilibrium method and an express method based on the algorithm described in the article. It is shown that the use of the algorithm for calculating the heat transfer coefficient of the body of an isothermal vehicle will not only increase the productivity of testing stations, but will also lead to the organization of an electronic passport for the thermotechnical state for each body of an isothermal vehicle, the control of which will enable timely diagnosing the thermo-technical condition of the bodies of isothermal vehicles, providing energy-optimal operating modes of energy equipment and, hence, increasing its resource.

At present, large-capacity refrigerated containers (LCRC) are widely used for the transport of perishable goods. Transportation of such containers by rail is carried out by couplings of 10-12 fitting platforms and a car with diesel-electric power station. Analysis of this method of transporting large-capacity refrigerated containers by rail showed that it has a number of shortcomings that complicate the transportation process and increase the costs of the carrier (or perishable freight owner).Reduction of costs for the transportation of LCRC can be achieved by equipping the fitting platforms with an autonomous power supply system with a generator-drive unit (GPU) from the axis of the wheel pair of the bogie. However, most of the fitting platforms are installed on three-piece freight bogies, and this creates certain difficulties when embedding the GPU into the undercarriage space.Based on the performed analysis of domestic and foreign designs of generator-driven units and the results of studies for 18-100 three-element freight bogies, it is recommended to use a two-stage drive from the wheel pair axis consisting of a single-stage gear reducer and a V-belt drive, allowing to achieve a total gear ratio of 5,3.According to the chosen scheme, design documentation was developed and two prototypes were made. Experimental samples of GPU with a two-stage drive passed preliminary and acceptance tests, according to the results of which it is recommended to make an installation batch. At present, two 60-foot fitting platforms equipped with an autonomous power supply system are being manufactured for the purpose of carrying out running tests.

In many areas of the economy the problem of bringing a complex control object at a predetermined state corresponding to a preassigned certain requirements arises. To solve it, the terminal management method is used. A typical example of tasks of terminal control is to manage synchronization of the tank emptying with the petroleum product with simultaneous synchronous writing off of its mass recorded in the database during supply of oil products. The article addresses the control method of supply of petroleum products to the consumer that allows in the terminal time to save the initial value of unbalance between the actual mass of oil product in a reservoir, and the mass of oil product indicated in the accounting documentation. In practice, the method can be implemented with control algorithm of terminal control, provided that the relative error of the incoming of the actual mass of oil product to the tank is within the range stated in regulations. The article offers mathematical apparatus, based on results of probability theory and statistical decision theory, showing that the use of control method allows keeping the original supplier relative error for oil product when it is delivered to the consumer, not increasing it by the error of measuring instruments by tank and / or accounting site.

To adapt container flats for transportation of high-capacity reefers (HCR) there was developed stand-alone power supply system (SAPSS) to be mounted on the flatcar three-piece freight bogie. Such a system ensures power supply to HCR all over the travel route by rail. One of the SAPSS key components proves to be generator drive unit comprising generator, V-belt transmission and single-reduction gear unit with dissectible driving gear mounted in the midpart of the wheelset axle. To confirm workability of the generator drive unit and obtain its pull and energy characteristics there were conducted rig tests of its prototype using for this purpose exerciser developed by the VNIIZhT design center. The exerciser was equipped with instrumentation systems capable to determine V-belt tension by the tension screw force value and assess slipping by rotating speeds of the driving and driven V-belt pulleys. Rig tests implied container flat running at various speeds. Three SAPSS loading modes were tested inclusive of open circuit operation. There was purposely developed testing procedure, allowing to assess slipping of the V-belt transmission within the accuracy of 0.01 %. Experimental data were collated with calculation results obtained by the authors beforehand. The SAPSS prototype tests outcomes evidence that generator drive unit is capable to support the system operation at power levels up to 16±1 kW within the container flat running speed range from 30 to 132 kph.

M dwarfs are common host stars to exoplanets but often lack atmospheric abundance measurements. Late-M dwarfs are also good analogs to the youngest substellar companions, which share similar T eff ∼ 2300–2800 K. We present atmospheric analyses for the M7.5 companion HIP 55507 B and its K6V primary star with Keck/KPIC high-resolution (R ∼ 35,000) K -band spectroscopy. First, by including KPIC relative radial velocities between the primary and secondary in the orbit fit, we improve the dynamical mass precision by 60% and find M B = 88.0 − 3.2 + 3.4 M Jup , putting HIP 55507 B above the stellar–substellar boundary. We also find that HIP 55507 B orbits its K6V primary star with a = 38 − 3 + 4 au and e = 0.40 ± 0.04. From atmospheric retrievals of HIP 55507 B, we measure [C/H] = 0.24 ± 0.13, [O/H] = 0.15 ± 0.13, and C/O = 0.67 ± 0.04. Moreover, we strongly detect 13CO (7.8 σ significance) and tentatively detect H 2 18 O (3.7 σ significance) in the companion's atmosphere and measure 12 CO / 13 CO = 98 − 22 + 28 and H 2 16 O / H 2 18 O = 240 − 80 + 145 after accounting for systematic errors. From a simplified retrieval analysis of HIP 55507 A, we measure 12 CO / 13 CO = 79 − 16 + 21 and C 16 O / C 18 O = 288 − 70 + 125 for the primary star. These results demonstrate that HIP 55507 A and B have consistent 12C/13C and 16O/18O to the <1 σ level, as expected for a chemically homogeneous binary system. Given the similar flux ratios and separations between HIP 55507 AB and systems with young substellar companions, our results open the door to systematically measuring 13CO and H 2 18 O abundances in the atmospheres of substellar or even planetary-mass companions with similar spectral types. [ABSTRACT FROM AUTHOR]

As the closest transiting hot Jupiter to Earth, HD 189733b has been the benchmark planet for atmospheric characterization 1-3 . It has also been the anchor point for much of our theoretical understanding of exoplanet atmospheres from composition 4 , chemistry 5,6 , aerosols 7 to atmospheric dynamics 8 , escape 9 and modelling techniques 10,11 . Previous studies of HD 189733b have detected carbon and oxygen-bearing molecules H 2 O and CO (refs.  12,13 ) in the atmosphere. The presence of CO 2 and CH 4 has been claimed 14,15 but later disputed 12,16,17 . The inferred metallicity based on these measurements, a key parameter in tracing planet formation locations 18 , varies from depletion 19,20 to enhancement 21,22 , hindered by limited wavelength coverage and precision of the observations. Here we report detections of H 2 O (13.4σ), CO 2 (11.2σ), CO (5σ) and H 2 S (4.5σ) in the transmission spectrum (2.4-5.0 μm) of HD 189733b. With an equilibrium temperature of about 1,200 K, H 2 O, CO and H 2 S are the main reservoirs for oxygen, carbon and sulfur. Based on the measured abundances of these three main volatile elements, we infer an atmospheric metallicity of three to five times stellar. The upper limit on the methane abundance at 5σ is 0.1 ppm, which indicates a low carbon-to-oxygen ratio (<0.2), suggesting formation through the accretion of water-rich icy planetesimals. The low oxygen-to-sulfur and carbon-to-sulfur ratios also support the planetesimal accretion formation pathway 23 ., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Stellar winds of cool and pulsating asymptotic giant branch (AGB) stars enrich the interstellar medium with large amounts of processed elements and various types of dust. We present the first study on the influence of gas-to-dust drift on ab initio simulations of stellar winds of M-type stars driven by radiation pressure on forsterite particles. Our study is based on our radiation hydrodynamic model code T-800 that includes frequency-dependent radiative transfer, dust extinction based on Mie scattering, grain growth and ablation, gas-to-dust drift using one mean grain size, a piston that simulates stellar pulsations, and an accurate high spatial resolution numerical scheme. To enable this study, we calculated new gas opacities based on the EXOMOL database, and we extended the model code to handle the formation of minerals that may form in M-type stars. We determine the effects of drift by comparing drift models to our new and extant non-drift models. Three out of four new drift models show high drift velocities, 87–310 km s−1. Our new drift model mass-loss rates are 1.7–13 per cent of the corresponding values of our non-drift models, but compared to the results of two extant non-drift models that use the same stellar parameters, these same values are 0.33–1.5 per cent. Meanwhile, a comparison of other properties such as the expansion velocity and grain size show similar values. Our results, which are based on single-component forsterite particles, show that the inclusion of gas-to-drift is of fundamental importance in stellar wind models driven by such transparent grains. Assuming that the drift velocity is insignificant, properties such as the mass-loss rate may be off from more realistic values by a factor of 50 or more. [ABSTRACT FROM AUTHOR]

Observations of transiting gas giant exoplanets have revealed a pervasive depletion of methane 1-4 , which has only recently been identified atmospherically 5,6 . The depletion is thought to be maintained by disequilibrium processes such as photochemistry or mixing from a hotter interior 7-9 . However, the interiors are largely unconstrained along with the vertical mixing strength and only upper limits on the CH 4 depletion have been available. The warm Neptune WASP-107b stands out among exoplanets with an unusually low density, reported low core mass 10 , and temperatures amenable to CH 4 , though previous observations have yet to find the molecule 2,4 . Here we present a JWST-NIRSpec transmission spectrum of WASP-107b that shows features from both SO 2 and CH 4 along with H 2 O, CO 2 , and CO. We detect methane with 4.2σ significance at an abundance of 1.0 ± 0.5 ppm, which is depleted by 3 orders of magnitude relative to equilibrium expectations. Our results are highly constraining for the atmosphere and interior, which indicate the envelope has a super-solar metallicity of 43 ± 8 × solar, a hot interior with an intrinsic temperature of T int  = 460 ± 40 K, and vigorous vertical mixing which depletes CH 4 with a diffusion coefficient of K zz  = 10 11.6±0.1  cm 2  s -1 . Photochemistry has a negligible effect on the CH 4 abundance but is needed to account for the SO 2 . We infer a core mass of 11.5 - 3.6 + 3.0 M ⊕ , which is much higher than previous upper limits 10 , releasing a tension with core-accretion models 11 ., (© 2024. The Author(s).)

Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability1. However, no unambiguous photochemical products have been detected in exoplanet atmospheres so far. Recent observations from the JWST Transiting Exoplanet Community Early Release Science Program2,3 found a spectral absorption feature at 4.05 μm arising from sulfur dioxide (SO2) in the atmosphere of WASP-39b. WASP-39b is a 1.27-Jupiter-radii, Saturn-mass (0.28 MJ) gas giant exoplanet orbiting a Sun-like star with an equilibrium temperature of around 1,100 K (ref. 4). The most plausible way of generating SO2 in such an atmosphere is through photochemical processes5,6. Here we show that the SO2 distribution computed by a suite of photochemical models robustly explains the 4.05-μm spectral feature identified by JWST transmission observations7 with NIRSpec PRISM (2.7σ)8 and G395H (4.5σ)9. SO2 is produced by successive oxidation of sulfur radicals freed when hydrogen sulfide (H2S) is destroyed. The sensitivity of the SO2 feature to the enrichment of the atmosphere by heavy elements (metallicity) suggests that it can be used as a tracer of atmospheric properties, with WASP-39b exhibiting an inferred metallicity of about 10× solar. We further point out that SO2 also shows observable features at ultraviolet and thermal infrared wavelengths not available from the existing observations.Observations from the JWST show the presence of a spectral absorption feature at 4.05 μm arising from SO2 in the atmosphere of the gas giant exoplanet WASP-39b, which is produced by photochemical processes and verified by numerical models. [ABSTRACT FROM AUTHOR]

The perfection of methods and means of nondestructive testing and technical diagnostics is determined by the level of development of science and modern industrial technologies. The desire to develop technologies determines the extent and degree to which the monitoring of the state of substances, materials, products—and now the state of the natural environment—are becoming increasingly relevant. The methods and means of condition monitoring and the diagnostics of rolling bearings have been in development for more than 60 years. Despite some successes, however, there is currently no information concerning the veracity of means to completely resolve the bearing diagnostics problem. This paper provides a fairly brief overview of methods and means for monitoring the condition and diagnosis of rolling bearings and also describes one of the newest trends in this field—the analysis of the properties of the characteristic function of vibroacoustic (VA) signals in order to determine the condition of the objects of control and, in particular, rolling bearings. It is shown that the magnitude of the module and the area of the characteristic function of the VA signal are very effective criteria for assessing the technical condition of a rolling bearing. [ABSTRACT FROM AUTHOR]

Based on advanced spectroscopic databases, line-by-line and layer-by-layer radiative transfer codes numerically solve the radiative transfer equation with very high accuracy. Taking advantage of its pre-calculated optical depth lookup table, the fast and accurate radiative transfer model Automatized Atmospheric Absorption Atlas OPerational (4A/OP) calculates the transmission and radiance spectra for a user-defined layered atmospheric model. Here, we present a module called 4A-Flux, which is developed and implemented into 4A/OP in order to include the calculation of the clear-sky longwave radiative flux profiles and heating rate profiles at a very high spectral resolution. Calculations are performed under the assumption of local thermodynamic equilibrium, a plane-parallel atmosphere, and specular reflection on the surface. The computation takes advantage of pre-tabulated exponential integral functions that are used instead of a classic angular quadrature. Furthermore, the sub-layer variation of the Planck function is implemented to better represent the emission of layers with a high optical depth. Thanks to the implementation of 4A-Flux, 4A/OP models have participated in the Radiative Forcing Model Intercomparison Project (RFMIP-IRF) along with other state-of-the-art radiative transfer models. 4A/OP hemispheric flux profiles are compared to other models over the 1800 representative atmospheric situations of RFMIP, yielding an outgoing longwave radiation (OLR) mean difference between 4A/OP and other models of -0.148 Wm-2 and a standard deviation of 0.218 Wm-2 , showing a good agreement between 4A/OP and other models. 4A/OP is applied to the Thermodynamic Initial Guess Retrieval (TIGR) atmospheric database to analyze the response of the OLR and vertical heating rate to several perturbations of temperature or gas concentration. This work shows that 4A/OP with 4A-Flux module can successfully be used to simulate accurate flux and heating rate profiles and provide useful sensitivity studies including sensitivities to minor trace gases such as HFC134a, HCFC22, and CFC113. We also highlight the interest for the modeling community to extend intercomparison between models to comparisons between spectroscopic databases and modeling to improve the confidence in model simulations. [ABSTRACT FROM AUTHOR]

The power of most of the enterobacterial O antigen types to provide robust protection against direct recognition of the cell surface by bacteriophage receptor-recognition proteins (RBP) has been recently recognized. The bacteriophages infecting O antigen producing strains of E. coli employ various strategies to tackle this nonspecific protection. T-even related phages, including RB49-like viruses, often have wide host ranges, being considered good candidates for use in phage therapy. However, the mechanisms by which these phages overcome the O antigen barrier remain unknown. We demonstrate here that RB49 and related phages Cognac49 and Whisky49 directly use certain types of O antigen as their primary receptors recognized by the virus long tail fibers (LTF) RBP gp38, so the O antigen becomes an attractant instead of an obstacle. Simultaneously to recognize multiple O antigen types, LTFs of each of these phages can bind to additional receptors, such as OmpA protein, enabling them to infect some rough strains of E. coli. We speculate that the mechanical force of the deployment of the short tail fibers (STF) triggered by the LTF binding to the O antigen or underneath of it, allows the receptor binding domains of STF to break through the O polysaccharide layer. [ABSTRACT FROM AUTHOR]

The influence of a weak stationary magnetic field on the decay kinetics of photo voltage in solar-Si crystals is studied. The features in the behavior of electrophysical parameters showed that the stability of the short-term and long-term components of photo voltage depends on the duration of magnetic treatment. Short time of magnetic treatment leads to increase, and long magnetic treatment causes reduction both components of photo voltage in comparison with control crystals. It is revealed that character of magneto stimulated change of photo voltage kinetics correlates with a charge condition of surface. [ABSTRACT FROM AUTHOR]

Brown dwarfs serve as ideal laboratories for studying the atmospheres of giant exoplanets on wide orbits, as the governing physical and chemical processes within them are nearly identical 1,2 . Understanding the formation of gas-giant planets is challenging, often involving the endeavour to link atmospheric abundance ratios, such as the carbon-to-oxygen (C/O) ratio, to formation scenarios 3 . However, the complexity of planet formation requires further tracers, as the unambiguous interpretation of the measured C/O ratio is fraught with complexity 4 . Isotope ratios, such as deuterium to hydrogen and 14 N/ 15 N, offer a promising avenue to gain further insight into this formation process, mirroring their use within the Solar System 5-7 . For exoplanets, only a handful of constraints on 12 C/ 13 C exist, pointing to the accretion of 13 C-rich ice from beyond the CO iceline of the disks 8,9 . Here we report on the mid-infrared detection of the 14 NH 3 and 15 NH 3 isotopologues in the atmosphere of a cool brown dwarf with an effective temperature of 380 K in a spectrum taken with the Mid-Infrared Instrument (MIRI) of JWST. As expected, our results reveal a 14 N/ 15 N value consistent with star-like formation by gravitational collapse, demonstrating that this ratio can be accurately constrained. Because young stars and their planets should be more strongly enriched in the 15 N isotope 10 , we expect that 15 NH 3 will be detectable in several cold, wide-separation exoplanets., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

The abundances of main carbon- and oxygen-bearing gases in the atmospheres of giant exoplanets provide insights into atmospheric chemistry and planet formation processes 1,2 . Thermochemistry suggests that methane (CH 4 ) should be the dominant carbon-bearing species below about 1,000 K over a range of plausible atmospheric compositions 3 ; this is the case for the solar system planets 4 and has been confirmed in the atmospheres of brown dwarfs and self-luminous, directly imaged exoplanets 5 . However, CH 4 has not yet been definitively detected with space-based spectroscopy in the atmosphere of a transiting exoplanet 6-11 , but a few detections have been made with ground-based, high-resolution transit spectroscopy 12,13 including a tentative detection for WASP-80b (ref. 14 ). Here we report transmission and emission spectra spanning 2.4-4.0 μm of the 825 K warm Jupiter WASP-80b taken with the NIRCam instrument of the JWST, both of which show strong evidence of CH 4 at greater than 6σ significance. The derived CH 4 abundances from both viewing geometries are consistent with each other and with solar to sub-solar C/O and around five times solar metallicity, which is consistent with theoretical predictions 15-17 ., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Transmission spectroscopy is one of the premier methods used to probe the temperature, composition, and cloud properties of exoplanet atmospheres. Recent studies have demonstrated that the multidimensional nature of exoplanet atmospheresâ€"due to nonuniformities across the dayâ€"night transition and between the morning and evening terminatorsâ€"can strongly influence transmission spectra. However, the computational demands of 3D radiative-transfer techniques have precluded their usage within atmospheric retrievals. Here we introduce TRIDENT, a new 3D radiative-transfer model which rapidly computes transmission spectra of exoplanet atmospheres with dayâ€"night, morningâ€"evening, and vertical variations in temperature, chemical abundances, and cloud properties. We also derive a general equation for transmission spectra, accounting for 3D atmospheres, refraction, multiple scattering, ingress/egress, grazing transits, stellar heterogeneities, and nightside thermal emission. After introducing TRIDENT’s linear-algebra-based approach to 3D radiative transfer, we propose new parametric prescriptions for 3D temperature and abundance profiles and 3D clouds. We show that multidimensional transmission spectra exhibit two significant observational signatures: (i) dayâ€"night composition gradients alter the relative amplitudes of absorption features; and (ii) morningâ€"evening composition gradients distort the peak-to-wing contrast of absorption features. Finally, we demonstrate that these signatures of multidimensional atmospheres incur residuals >100 ppm compared to 1D models, rendering them potentially detectable with the James Webb Space Telescope. TRIDENT’s rapid radiative transfer, coupled with parametric multidimensional atmospheres, unlocks the final barrier to 3D atmospheric retrievals. [ABSTRACT FROM AUTHOR]

Measurements of the atmospheric carbon (C) and oxygen (O) relative to hydrogen (H) in hot Jupiters (relative to their host stars) provide insight into their formation location and subsequent orbital migration1,2. Hot Jupiters that form beyond the major volatile (H2O/CO/CO2) ice lines and subsequently migrate post disk-dissipation are predicted have atmospheric carbon-to-oxygen ratios (C/O) near 1 and subsolar metallicities2, whereas planets that migrate through the disk before dissipation are predicted to be heavily polluted by infalling O-rich icy planetesimals, resulting in C/O < 0.5 and super-solar metallicities1,2. Previous observations of hot Jupiters have been able to provide bounded constraints on either H2O (refs. 3–5) or CO (refs. 6,7), but not both for the same planet, leaving uncertain4 the true elemental C and O inventory and subsequent C/O and metallicity determinations. Here we report spectroscopic observations of a typical transiting hot Jupiter, WASP-77Ab. From these, we determine the atmospheric gas volume mixing ratio constraints on both H2O and CO (9.5 × 10−5–1.5 × 10−4 and 1.2 × 10−4–2.6 × 10−4, respectively). From these bounded constraints, we are able to derive the atmospheric C/H ( 0.35 − 0.10 + 0.17 × solar) and O/H ( 0.32 − 0.08 + 0.12 × solar) abundances and the corresponding atmospheric carbon-to-oxygen ratio (C/O = 0.59 ± 0.08; the solar value is 0.55). The sub-solar (C+O)/H ( 0.33 − 0.09 + 0.13 × solar) is suggestive of a metal-depleted atmosphere relative to what is expected for Jovian-like planets1 while the near solar value of C/O rules out the disk-free migration/C-rich2 atmosphere scenario.The C/O ratio of the transiting hot Jupiter WASP-77Ab is measured here and found to be approximately solar, though the (C+O)/H ratio is subsolar. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2 ) is a key chemical species that is found in a wide range of planetary atmospheres. In the context of exoplanets, CO 2 is an indicator of the metal enrichment (that is, elements heavier than helium, also called 'metallicity') 1-3 , and thus the formation processes of the primary atmospheres of hot gas giants 4-6 . It is also one of the most promising species to detect in the secondary atmospheres of terrestrial exoplanets 7-9 . Previous photometric measurements of transiting planets with the Spitzer Space Telescope have given hints of the presence of CO 2 , but have not yielded definitive detections owing to the lack of unambiguous spectroscopic identification 10-12 . Here we present the detection of CO 2 in the atmosphere of the gas giant exoplanet WASP-39b from transmission spectroscopy observations obtained with JWST as part of the Early Release Science programme 13,14 . The data used in this study span 3.0-5.5 micrometres in wavelength and show a prominent CO 2 absorption feature at 4.3 micrometres (26-sigma significance). The overall spectrum is well matched by one-dimensional, ten-times solar metallicity models that assume radiative-convective-thermochemical equilibrium and have moderate cloud opacity. These models predict that the atmosphere should have water, carbon monoxide and hydrogen sulfide in addition to CO 2 , but little methane. Furthermore, we also tentatively detect a small absorption feature near 4.0 micrometres that is not reproduced by these models., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

The Saturn-mass exoplanet WASP-39b has been the subject of extensive efforts to determine its atmospheric properties using transmission spectroscopy 1-4 . However, these efforts have been hampered by modelling degeneracies between composition and cloud properties that are caused by limited data quality 5-9 . Here we present the transmission spectrum of WASP-39b obtained using the Single-Object Slitless Spectroscopy (SOSS) mode of the Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument on the JWST. This spectrum spans 0.6-2.8 μm in wavelength and shows several water-absorption bands, the potassium resonance doublet and signatures of clouds. The precision and broad wavelength coverage of NIRISS/SOSS allows us to break model degeneracies between cloud properties and the atmospheric composition of WASP-39b, favouring a heavy-element enhancement ('metallicity') of about 10-30 times the solar value, a sub-solar carbon-to-oxygen (C/O) ratio and a solar-to-super-solar potassium-to-oxygen (K/O) ratio. The observations are also best explained by wavelength-dependent, non-grey clouds with inhomogeneous coverageof the planet's terminator., (© 2023. The Author(s).)

Although structural phase transitions in single-crystal hybrid methyl-ammonium (MA) lead halide perovskites (MAPbX3, X = Cl, Br, I) as a function of temperature are common phenomena, they have never been observed in the corresponding nanocrystals. Here, we demonstrate that two-photon-excited photoluminescence (PL) spectroscopy is capable of monitoring structural phase transitions in MAPbX3 nanocrystals because nonlinear susceptibilities govern the incident light absorption rates. We provide experimental evidence that the orthorhombic-to-tetragonal structural phase transition in a single layer of 20-nm-sized 3D MAPbBr3 nanocrystals is spread out within the T ∼ 70 K–140 K temperature range. This structural phase instability is believed to arise because, unlike in single-crystal MAPbX3, free rotations of MA ions in the corresponding nanocrystals are no longer restricted by a long-range MA dipole order. The resulting configurational entropy loss can be even enhanced by the interfacial electric field arising due to charge separation at the MAPbBr3/ZnO heterointerface, extending the structural phase instability range from T ∼ 70 K–230 K. We conclude that weak sensitivity of conventional one-photon-excited PL spectroscopy to structural phase transitions in 3D MAPbX3 nanocrystals results from structural phase instability and hence from negligible distortions of PbX6 octahedra. In contrast, the intensity of two-photon-excited PL and electric-field-induced one-photon-excited PL show higher sensitivity since nonlinear susceptibilities are involved. We also show that room-temperature PL may originate from the radiative recombination of the optical-phonon vibrationally excited polaronic excitons with energies might exceed the ground-state Fröhlich polaron and Rashba energies due to optical-phonon bottleneck. [ABSTRACT FROM AUTHOR]

Copyright of Nanosistemi, Nanomateriali, Nanotehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Context. Future instruments like the Near Infrared Camera (NIRCam) and the Mid Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST) or the Mid-Infrared E-ELT Imager and Spectrograph (METIS) at the European Extremely Large Telescope (E-ELT) will be able to image exoplanets that are too faint (because they have a low mass, and hence a small size or low effective temperature) for current direct imaging instruments. On the theoretical side, core accretion formation models predict a significant population of low-mass and/or cool planets at orbital distances of ~10–100 au. Aims. Evolutionary models predicting the planetary intrinsic luminosity as a function of time have traditionally concentrated on gas-dominated giant planets. We extend these cooling curves to Saturnian and Neptunian planets. Methods. We simulated the cooling of isolated core-dominated and gas giant planets with masses of 5 M⊕–2 M♃. The planets consist of a core made of iron, silicates, and ices surrounded by a H/He envelope, similar to the ice giants in the solar system. The luminosity includes the contribution from the cooling and contraction of the core and of the H/He envelope, as well as radiogenic decay. For the atmosphere we used grey, AMES-Cond, petitCODE, and HELIOS models. We considered solar and non-solar metallicities as well as cloud-free and cloudy atmospheres. The most important initial conditions, namely the core-to-envelope-mass ratio and the initial (i.e. post formation) luminosity are taken from planet formation simulations based on the core accretion paradigm. Results. We first compare our cooling curves for Uranus, Neptune, Jupiter, Saturn, GJ 436b, and a 5 M⊕ planet with a 1% H/He envelope with other evolutionary models. We then present the temporal evolution of planets with masses between 5 M⊕ and 2 M♃ in terms of their luminosity, effective temperature, radius, and entropy. We discuss the impact of different post formation entropies. For the different atmosphere types and initial conditions, magnitudes in various filter bands between 0.9 and 30 micrometer wavelength are provided. Conclusions. Using blackbody fluxes and non-grey spectra, we estimate the detectability of such planets with JWST. We found that a 20 (100) M⊕ planet can be detected with JWST in the background limit up to an age of about 10 (100) Myr with NIRCam and MIRI, respectively. [ABSTRACT FROM AUTHOR]

The highly accurate measurements of the hyperspectral Infrared Atmospheric Sounding Interferometer (IASI) are used in numerical weather prediction (NWP), atmospheric chemistry and climate monitoring. As the second generation of the European Polar System (EPS-SG) is being developed, a new generation of IASI instruments has been designed to fly on board the MetOp-SG constellation: IASI New Generation (IASI-NG). In order to prepare the arrival of this new instrument, and to evaluate its impact on NWP and atmospheric chemistry applications, a set of IASI and IASING simulated data was built and made available to the public to set a common framework for future impact studies. This paper describes the information available in this database and the procedure followed to run the IASI and IASI-NG simulations. These simulated data were evaluated by comparing IASI-NG to IASI observations. The result is also presented here. Additionally, preliminary impact studies of the benefit of IASI-NG compared to IASI on the retrieval of temperature and humidity in a NWP framework are also shown in the present work. With a channel dataset located in the same wave numbers for both instruments, we showed an improvement of the temperature retrievals throughout the atmosphere, with a maximum in the troposphere with IASI-NG and a lower benefit for the tropospheric humidity. [ABSTRACT FROM AUTHOR]

Copyright of Nanosistemi, Nanomateriali, Nanotehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)