Cloudburst events observed over Uttarakhand during monsoon season 2017 and their analysis

Cloudburst is an extreme weather event characterised by the occurrence of a large amount of rainfall over a small area within a short span of time with a rainfall of 100 mm or more in one hour. It is responsible for flash flood, inundation of low lying areas and landslides in hills causing extensive damages to life and property. During monsoon season 2017 five number of cloudburst events are observed over Uttarakhand and analysed. Self Recording Rain Gauge (SRRG) and 15 minutes interval data from the newly installed General Packet Radio Service (GPRS) based Automatic Weather Station (AWS) are able to capture the cloudburst events over some areas in Uttarakhand. In this paper, an attempt has been made to find out the significant synoptic and thermodynamic conditions associated with the occurrence of the cloudburst events in Uttarakhand. These 5 cases of cloudburst events that are captured during the month of June, July and August 2017 in Uttarakhand are studied in detail. Synoptically, it is observed that the existence of trough at mean sea level from Punjab to head Bay of Bengal running close to Uttarakhand, the movement of Western Disturbance over north Pakistan and adjoining Jammu & Kashmir and existence of cyclonic circulation over north Rajasthan and neighbourhood are favourable conditions. Also, the presence of strong south-westerly wind flow from the Arabian Sea across West Rajasthan and Haryana on upper air charts are found during these events. Thermodynamically, the Convective Available Potential Energy (CAPE) is found to be high (more than 1100 J/Kg) during most of the cases and vertically integrated precipitable water content (PWC) is more than 55mm. The GPRS based AWS system can help in prediction of the cloud burst event over the specified location with a lead time upto half to one hour in association with radar products.

Significant influence of self-possessed moisture of limonitic nickel laterite on sintering performance and its action mechanism

In consideration of the abundant moisture of limonitic nickel laterite mined, it is essential to determine whether the self-possessed moisture of limonitic nickel laterite after pre-dried is appropriate for sintering. Thus, based on the characterization of limonitic nickel laterite, the influence of its self-possessed moisture on sintering performance was expounded by sinter pot tests and the relevant mechanism was revealed by the systematical analyses of the granulation properties of sinter mixture, thermodynamic conditions during sintering and mineralogy of product sinter. The results indicate that the self-possessed moisture of limonitic nickel laterite indeed has significant influence on its sintering performance. At the optimum self-possessed moisture of 21 mass%, sinter indices are relatively better with tumble index, productivity and solid fuel rate of 48.87%, 1.04 t m−2 h−1 and 136.52 kg t−1, respectively, due to the superior granulation properties of sinter mixture and thermodynamic conditions during sintering, relatively large amount of silico-ferrite of calcium and alumina and tighter sinter microstructure. However, sintering performance of limonitic nickel laterite is still much poorer than that of ordinary iron ores. It is feasible to strengthen limonitic nickel laterite sintering by inhibiting the over-fast sintering speed and improving the thermodynamic conditions during sintering.

The research and development of technical and technological solutions for the operation of oil wells with increased gas content

In the practice of oil production, there are oil deposits with high values of gas content (gas factor), from tens to hundreds of cubic meters of gas per one ton of oil produced. Gas dissolved in oil and coming from the reservoir into the well along with the liquid phase (oil, water), under certain thermodynamic conditions, is capable of forming hydrates, which complicate the operation of downhole pumping equipment, reduce the efficiency of pumps and well flow rate. The formation of gas hydrate plugs in the well requires the total overhaul, which leads to an increase in non-productive time, financial costs and an increase in lost profits on lost oil. Considered in the article technologies and devices that prevent the formation of gas hydrates in marginal wells with a high gas content in oil have shown their unreliability and low efficiency. The authors propose for the consideration a new effective technology for the operation of such wells, which makes it possible to avoid the formation of hydrates. Keywords: well; gas content; hydrates; production; oil; valve; coupling; pump.

Extremely Non-Auxetic Behavior of a Typical Auxetic Microstructure Due to Its Material Properties

The re-entrant honeycomb microstructure is one of the most famous, typical examples of an auxetic structure. The re-entrant geometries also include other members as, among others, the star re-entrant geometries with various symmetries. In this paper, we focus on one of them, having a 6-fold symmetry axis. The investigated systems consist of binary hard discs (two-dimensional particles with two slightly different sizes, interacting through infinitely repulsive pairwise potential), from which different structures, based on the mentioned geometry, were formed. To study the elastic properties of the systems, computer simulations using the Monte Carlo method in isobaric-isothermal ensemble with varying shape of the periodic box were performed. The results show that all the considered systems are isotropic and not auxetic—their Poisson’s ratio is positive in each case. Moreover, Poisson’s ratios of the majority of examined structures tend to +1 with increasing pressure, which is the upper limit for two-dimensional isotropic media, thus they can be recognized as the ideal non-auxetics in appropriate thermodynamic conditions. The results obtained contradict the common belief that the unique properties of metamaterials result solely from their microstructure and indicate that the material itself can be crucial.

Investigating realistic anode off-gas combustion in SOFC/ICE hybrid systems: mini review and experimental evaluation

Solid oxide fuel cells (SOFCs) have been deployed in hybrid decentralized energy systems, in which they are directly coupled to internal combustion engines (ICEs). Prior research indicated that the anode tailgas exiting the SOFC stack should be additionally exploited due to its high energy value, with typical ICE operation favoring hybridization due to matching thermodynamic conditions during operation. Consequently, extensive research has been performed, in which engines are positioned downstream the SOFC subsystem, operating in several modes of combustion, with the most prevalent being homogeneous compression ignition (HCCI) and spark ignition (SI). Experiments were performed in a 3-cylinder ICE operating in the latter modus operandi, where the anode tailgas was assimilated by mixing syngas (H2: 33.9%, CO: 15.6%, CO2: 50.5%) with three different water vapor flowrates in the engine’s intake. While increased vapor content significantly undermined engine performance, brake thermal efficiency (BTE) surpassed 34% in the best case scenario, which outperformed the majority of engines operating under similar operating conditions, as determined from the conducted literature review. Nevertheless, the best performing application was identified operating under HCCI, in which diesel reformates assimilating SOFC anode tailgas, fueled a heavy duty ICE (17:1), and gross indicated thermal efficiency ([Formula: see text]) of 48.8% was achieved, with the same engine exhibiting identical performance when operating in reactivity-controlled compression ignition (RCCI). Overall, emissions in terms of NOx and CO were minimal, especially in SI engines, while unburned hydrocarbons (UHC) were non-existent due to the absence of hydrocarbons in the assessed reformates.

Deep Eye Clouds Observed in Tropical Cyclone Trami (2018) during T-PARCII Dropsonde Observations

The sporadic formation of short-lived convective clouds in the eye of Tropical Cyclone (TC) Trami (2018) is investigated using dropsonde data and simulation results from a coupled atmosphere–ocean model. According to the satellite data, top height of the convective clouds exceeds 9 km above mean sea level, considerably taller than that of typical hub clouds (2–3 km). These clouds are located 10–30 km away from the TC center. Hence, these convective clouds are called deep eye clouds (DECs) in this study. The dropsonde data reveal increase in relative humidity in the eye region during the formation of DECs. Short-lived convective clouds are simulated up to the middle troposphere in the eye region in the coupled model. Investigation of thermodynamic conditions shows a weakened low-level warm core and associated favorable conditions for convection in the eye region during the formation of DECs. DECs are formed after the weakening and outward displacement of convective heating within the eyewall. To elucidate the influence of the changes in convective heating within the eyewall on the formation of DECs, we calculate secondary circulation and associated adiabatic warming induced by convective heating within the eyewall using the Sawyer–Eliassen equation. In the eye region, weakenings of subsidence and associated vertical potential temperature advection are observed as DECs are formed. This suggests that the weakening and outward displacement of convective heating within the eyewall create favorable conditions for the sporadic formation of DECs.

Application of Multifractal Analysis for Research of Structural Materials

Application of multifractal analysis for qualitative and quantitative description of structural materials is demonstrated. This makes it possible to evaluate the system’s characteristics of structures and to characterize the processes of self-organization in the materials. Formation of friction surface structures for aluminum alloys with Al2O3 and SiC additives in the scuffing mode is considered under comparable thermodynamic conditions. The addition of SiC, in comparison with Al2O3 , is less conducive to fragmentation and increase in the frequency of seizure and rupture processes. The addition of graphite into a composite material reinforced with SiC leads to increase in the degree of non-equilibrium of the thermodynamic conditions for the formation of the structures. Additional introduction of graphite further enhances the difference between materials with additions of Al2O3 and SiC, and this leads to the formation of the least ordered structures of the friction surface.

High-Energy Ejection of Molecules and Gas-Dust Outbursts in Coal Mines

In the current work, using the framework of the formalism found in the Bogolyubov–Born–Green–Kirkwood–Yvon (BBGKY) equations for the distribution functions of particle groups, the effective single-particle potential near the surface of the liquid was analyzed. The thermodynamic conditions under which a sudden opening of the liquid surface leads to high-energy ejection of atoms and molecules were found. The energies of the emitted particles were observed to be able to significantly exceed their thermal energy. Criteria of the ejection stability of the liquid surface and the self-acceleration of ejection were formulated. The developed theory was used to explain the phenomenon of the self-acceleration of gas-dust outbursts in coal mines during the explosive opening of methane traps. The results also explained the mechanisms of generating significant amounts of methane and the formation of coal nanoparticles in gas-dust outbursts. The developed approach was also used to explain the phenomenon of the self-ignition of hydrogen when it enters the atmosphere.