Search

This paper presents experimental results concerning the one-step preparation of cast divanadium nitride and aluminum oxynitride (AlON) by high-temperature synthesis under 5 MPa of N 2 from green mixtures containing vanadium oxide, aluminum, and aluminum nitride. It was shown that the mixtures with a wide range of component ratios are capable to burn with the temperature exceeding the melting point of the final products, divanadium nitride and aluminum oxynitride, that makes it possible to obtain them in the form of a melt with subsequent separation of vanadium nitride (lower ingot) and aluminum oxynitride (upper ingot). The resulting products had no cohesion and were easily separated from each other. Variation in the content of aluminum nitride in the charge markedly affected the synthesis process, phase composition, and microstructure of the target products. The content of excess aluminum nitride in the starting mixture α = 10% was found to be optimum on a yield/composition of the target products. [ABSTRACT FROM AUTHOR]

The article reveals the necessity and relevance of precise pulse pressure measurement in industry, power engineering, and transportation. The design, operating principle, and the result of the metrological studies of GET 43-2022 State Primary Standard for the unit of excess pressure within the static pressure range of 10–1600 MPa and the pulse pressure range of 1–1200 MPa and the effective area of piston-cylinder assemblies in deadweight testers within the range of 0.05–1 cm2 are presented. GET 43-2022 includes hydraulic and pneumatic systems, as well as an ultrahigh-pressure valve designed to compare systems used in GET 43-2022 that operate with different standard liquids within the range of 250–1200 MPa. The reproduction range of the pulse pressure unit in GET 43-2022 is 1–1200 MPa. The method for reproducing the pulse pressure unit in liquid and gas media using hydraulic and pneumatic systems is described. The metrological characteristics of GET 43-2022 are studied; the budget of measurement uncertainty in reproducing the pulse pressure unit is estimated. The obtained results help to meet the development needs of the pool of working standards for pulse pressure measuring instruments traceable to GET 43-2022. [ABSTRACT FROM AUTHOR]

This study is aimed at comprehensively analyzing and estimating the effects in gas dynamics, as well as mechanical and optical effects, from the Kyiv meteoroid that entered the terrestrial atmosphere and exploded over Bila Tserkva raion, Kyiv oblast (Ukraine). According to the International Meteor Organization (IMO), the apparent magnitude of the meteoroid was –18. According to our estimates, the luminous power was 215 GW with an effective duration of 2.4 ± 0.2 s, the total luminous energy was 25.2 ± 2.5 GJ, and the initial kinetic energy was 0.09 ± 0.01 kt of TNT or 375 ± 35 GJ. The initial mass of the cosmic body was estimated to be 0.89 ± 0.09 t, the volume was 0.250 ± 0.025 m3, and the size was 79 ± 3 cm. The initial velocity of the meteoroid reached 29 km/s. The inclination angle, i.e., the angle that the trajectory makes with the horizontal plane, was 32°. The explosion altitude equal to 38 km and the inclination angle equal to 32° give an estimate of 3.5 t/m3 for the material density, which is close to the rock density. The energy of the processes, the gas dynamics effects, and the mechanical and optical effects from the celestial body have been analyzed. The main release of energy associated with the deceleration of the fragments of the celestial body, which was defragmented under a dynamical pressure of approximately 2.5 MPa, took place in the region with a length of 2 km at an altitude of approximately 38 km. A quasi-continuous defragmentation is suggested to produce a mass distribution that follows a power law. The main parameters of the ballistic and explosive shock waves have been estimated. For the Mach number of 97, the radius of the ballistic shock wave is estimated to be approximately 77 m, and the fundamental period to be 0.7 s, which showed a dispersive increase from 3.7 to 11.5 s with the propagation path length increasing from 50 to 5000 km. The radii of cylindrical and spherical wavefront shock waves were approximately 0.28 and 0.34 km, and their fundamental periods were approximately 2.6 and 3.2 s, respectively. These periods increased from 9.5 to 30.0 s and from 11.1 to 35.1 s with an increase in the propagation path length from 50 to 5000 km. In the vicinity of the meteoroid's explosion height, the relative excess pressure was a maximum. It decreased with a decrease in the altitude and increased with an increase in the altitude up to approximately 120–150 km, at which it attained values of approximately 6–7% and then further decreased down to a few percent. The absolute value of the excess pressure is estimated to be near the altitude of the explosion; subsequently it decreased with a decrease in the altitude down to 20–25 km and then increased further again. At the epicenter of the explosion, it is estimated to be approximately 94 Pa for the cylindrical wavefront and approximately 99 Pa for the spherical wavefront, which is not enough to damage objects on the ground. The excess pressure decreased with an increase in the altitude from 8–15 Pa to a few micropascals. Given an estimate of 2.4 s for the average duration of the effective light flash, the maximum power of the fireball is estimated to be 21 GW, and the power flux near the fireball (or more precisely, the cone 0.5 km in length and 2.4 m in diameter), is estimated to be 5.1 MW/m2. At the same time, the temperature is estimated to be approximately 3100 K, and the Wien wavelength is estimated to be 9.4 × 10–7 m. [ABSTRACT FROM AUTHOR]

The system’s excessive pressure management after zoning is essential for improving the existing water supply operation efficiency. Our original research proves that pressure control reduces the leaks in the water supply network, increasing the reliability level of the internal and external networks and saving energy consumed in pumping systems. In recent years, 243 pressure regulating valves (PRV) have been installed in the 97 zones of the expanded water supply network in the Yerevan city (the difference between the levels in the city reaches up to 500 meters) for pressure control in complex terrain conditions.

A new method to determine fluid flux at high pressures and temperatures has been developed and used to study serpentinites at subduction zone conditions. Drill cores of a natural antigorite‐serpentinite with a strong foliation were used in multi‐anvil experiments in the range of 2–5 GPa and 450–800°C. Fluids released upon dehydration are fixed by the formation of brucite in an adjacent fluid sink. The amount and distribution of brucite serves as a proxy for fluid flow. In our specific setup the sample reacted with the surrounding fluid sink to form an additional layer of olivine, which has the potential to limit fluid flux within our experiments. For conditions prior to serpentine dehydration we used Al(OH)3 as fluid source. Fluid in this experiment did not migrate through the serpentinite, indicating that serpentine has a low diffusivity. The experiments also show that small deviatoric stresses have an influence on the fluid flux and can cause an anisotropic fluid flux. Comparison between the time scales of the determined fluid flux with fluid production rates indicates fluid pressure buildup during dehydration reactions. Adjacent less permeable layers can inhibit fluid flux and cause fluid pressure buildup even at conditions when an interconnected pore space formed. Plain Language Summary: Subduction zones are regions where tectonic plates are recycled into the Earth's interior. Prior to subduction, the plates experienced extensive chemical interaction with the ocean water, forming hydrous minerals. Serpentine is an important hydrous mineral that can transport significant amounts of water into the Earth's interior. During subduction both pressure and temperature increase whereby hydrous minerals break down and release their water. The fluid migrates into the overlying mantle wedge, where it accounts for hydration as well as melting processes. The global flux balances would require this process to be very effective. However, it was so far not possible to measure the fluid flux at the subduction zone conditions in laboratories. In this study, we present a new method to determine the fluid flux prior and during dehydration. We found that prior to dehydration, the fluid flux in serpentinites is small. During dehydration the rocks ability to let fluids pass through increases. However, adjacent rocks with a low ability for fluid transport can further inhibit a fluid flux at these conditions. Generally, our experimental setup can be used for any system that immobilizes migrating fluids by hydration reactions. Key Points: A new method to determine fluid flux at high pressure and temperature conditions is developedSlow fluid migration in serpentinites promotes brittle fracturing in subduction zonesFast fluid migration upon dehydration of serpentinites promotes large‐scale fluid flux, if not inhibited by adjacent less permeable layers [ABSTRACT FROM AUTHOR]

Abstract A new method to determine fluid flux at high pressures and temperatures has been developed and used to study serpentinites at subduction zone conditions. Drill cores of a natural antigorite‐serpentinite with a strong foliation were used in multi‐anvil experiments in the range of 2–5 GPa and 450–800°C. Fluids released upon dehydration are fixed by the formation of brucite in an adjacent fluid sink. The amount and distribution of brucite serves as a proxy for fluid flow. In our specific setup the sample reacted with the surrounding fluid sink to form an additional layer of olivine, which has the potential to limit fluid flux within our experiments. For conditions prior to serpentine dehydration we used Al(OH)3 as fluid source. Fluid in this experiment did not migrate through the serpentinite, indicating that serpentine has a low diffusivity. The experiments also show that small deviatoric stresses have an influence on the fluid flux and can cause an anisotropic fluid flux. Comparison between the time scales of the determined fluid flux with fluid production rates indicates fluid pressure buildup during dehydration reactions. Adjacent less permeable layers can inhibit fluid flux and cause fluid pressure buildup even at conditions when an interconnected pore space formed.

One of the oldest methods of producing electrical energy is the use of latent energy in running water, which uses a water turbine to achieve this. It is one of the most important sources of renewable energy and has attracted the attention of many researchers in recent years. In this study, laboratory evaluation of hydraulic performance of a type of water microturbine to convert excess pressure in medium pressure water supply networks into electrical energy usable for sensors or equipment such as flow meters, pressure meters, leak detectors, etc., used to manage energy consumption and intelligent water supply networks is investigated. For this purpose, in three different scenarios, the effect of parameters such as flow rate, pressure and different angles of the guide vane on the microturbine performance and pressure drop was investigated. The results showed that the highest microturbine output power (59.01 watts) and pressure drop rate (9.71 meters H2O) were obtained when the inlet discharge was 42.61 m3/hr and the opening guide vane was 20 degrees. It also has the lowest output power (0.8 watts) and pressure drop rate (4.65 meters H2O) for a flow rate of 46 m3/hr without the guide vane. The coefficient of determination (R2) for the equations of microturbine output power and pressure drop was calculated to be 0.92 and 0.99, respectively.

Background: The arterial pressure waveform reflects the interaction between the heart and the arterial system and carries potentially relevant information about circulatory status. According to the commonly accepted 'wave transmission model', the net BP waveform results from the super-position of discrete forward and backward pressure waves, with the forward wave in systole determined mainly by the left ventricular (LV) ejection function and the backward by the wave reflection from the periphery, the timing and amplitude of which depend on arterial stiffness, the wave propagation speed and the extent of downstream admittance mismatching. However, this approach obscures the 'Windkessel function' of the elastic arteries. Recently, a 'reservoir-excess pressure' model has been proposed, which interprets the arterial BP waveform as a composite of a volume-related 'reservoir' pressure and a wave-related 'excess' pressure. Methods: In this study we applied the reservoir-excess pressure approach to the analysis of carotid arterial pressure waveforms (applanation tonometry) in 10 young healthy volunteers before and after a 5-week head down tilt bed rest which induced a significant reduction in stroke volume (SV), end-diastolic LV volume and LV longitudinal function without significant changes in central blood pressure, cardiac output, total peripheral resistance and aortic stiffness. Forward and backward pressure components were also determined by wave separation analysis. Results: Compared to the baseline state, bed rest induced a significant reduction in LV ejection time (LVET), diastolic time (DT), backward pressure amplitude (bP) and pressure reservoir integral (INTPR). INTPR correlated directly with LVET, DT, time to the peak of backward wave (bT) and stroke volume, while excess pressure integral (INTXSP) correlated directly with central pressure. Furthermore, Δ.INTPR correlated directly with Δ.LVET, and Δ.DT, and in multivariate analysis INTPR was independently related to LVET and DT and INTXSP to central systolic BP. Conclusion: This is an hypothesis generating paper which adds support to the idea that the reservoir-wave hypothesis applied to non-invasively obtained carotid pressure waveforms is of potential clinical usefulness. [ABSTRACT FROM AUTHOR]

BackgroundThe arterial pressure waveform reflects the interaction between the heart and the arterial system and carries potentially relevant information about circulatory status. According to the commonly accepted ‘wave transmission model’, the net BP waveform results from the super-position of discrete forward and backward pressure waves, with the forward wave in systole determined mainly by the left ventricular (LV) ejection function and the backward by the wave reflection from the periphery, the timing and amplitude of which depend on arterial stiffness, the wave propagation speed and the extent of downstream admittance mismatching. However, this approach obscures the ‘Windkessel function’ of the elastic arteries. Recently, a ‘reservoir-excess pressure’ model has been proposed, which interprets the arterial BP waveform as a composite of a volume-related ‘reservoir’ pressure and a wave-related ‘excess’ pressure.MethodsIn this study we applied the reservoir-excess pressure approach to the analysis of carotid arterial pressure waveforms (applanation tonometry) in 10 young healthy volunteers before and after a 5-week head down tilt bed rest which induced a significant reduction in stroke volume (SV), end-diastolic LV volume and LV longitudinal function without significant changes in central blood pressure, cardiac output, total peripheral resistance and aortic stiffness. Forward and backward pressure components were also determined by wave separation analysis.ResultsCompared to the baseline state, bed rest induced a significant reduction in LV ejection time (LVET), diastolic time (DT), backward pressure amplitude (bP) and pressure reservoir integral (INTPR). INTPR correlated directly with LVET, DT, time to the peak of backward wave (bT) and stroke volume, while excess pressure integral (INTXSP) correlated directly with central pressure. Furthermore, Δ.INTPR correlated directly with Δ.LVET, and Δ.DT, and in multivariate analysis INTPR was independently related to LVET and DT and INTXSP to central systolic BP.ConclusionThis is an hypothesis generating paper which adds support to the idea that the reservoir-wave hypothesis applied to non-invasively obtained carotid pressure waveforms is of potential clinical usefulness.

BACKGROUND Arterial reservoir-wave analysis (RWA)—a new model of arterial hemodynamics—separates arterial wave into reservoir pressure (RP) and excess pressure (XSP). The XSP integral (XSPI) has been associated with increased risk of clinical outcomes. The objectives of the present study were to examine the determinants of XSPI in a mixed cohort of hemodialysis (HD) and peritoneal dialysis (PD) patients, to examine whether dialysis modality and the presence of an arteriovenous fistula (AVF) are associated with increased XSPI. METHOD In a cross-sectional study, 290 subjects (232 HD and 130 with AVF) underwent carotid artery tonometry (calibrated with brachial diastolic and mean blood pressure). The XSPI was calculated through RWA using pressure-only algorithms. Logistic regression was used for determinants of XSPI above median. Through forward conditional linear regression, we examined whether treatment by HD or the presence of AVF is associated with higher XSPI. RESULTS Patients with XSPI above median were older, had a higher prevalence of diabetes and cardiovascular disease, had a higher body mass index, and were more likely to be on HD. After adjustment for confounders, HD was associated with a higher risk of higher XSPI (odds ratio = 2.39, 95% confidence interval: 1.16–4.98). In a forward conditional linear regression analysis, HD was associated with higher XSPI (standardized coefficient: 0.126, P = 0.012), but on incorporation of AVF into the model, AVF was associated with higher XSPI (standardized coefficient: 0.130, P = 0.008) and HD was excluded as a predictor. CONCLUSION This study suggests that higher XSPI in HD patients is related to the presence of AVF. [ABSTRACT FROM AUTHOR]

Background Reservoir‐wave approach is an alternative model of arterial hemodynamics based on the assumption that measured arterial pressure is composed of volume‐related (reservoir pressure) and wave‐related components (excess pressure). However, the clinical utility of reservoir‐wave approach remains debatable. Methods and Results In a single‐center cohort of 260 dialysis patients, we examined whether carotid and radial reservoir‐wave parameters were associated with all‐cause and cardiovascular mortality. Central pulse pressure and augmentation index at 75 beats per minute were determined by radial arterial tonometry through generalized transfer function. Carotid and radial reservoir‐wave analysis were performed to determine reservoir pressure and excess pressure integral. After a median follow‐up of 32 months, 171 (66%) deaths and 88 (34%) cardiovascular deaths occurred. In Cox regression analysis, carotid excess pressure integral was associated with a hazard ratio of 1.33 (95% CI, 1.14–1.54; P

The transverse distributed load on an elastic thin plate in a gas environment is determined. Different values of the pressure of the medium on both surfaces form both the pressure difference and the transverse unbalanced force depending on the average pressure and curvature of the mid-surface. It is shown that in the general case both of these components of the transverse force should be taken into account. With a small ratio of the average pressure to the elastic modulus of the plate material and a large relative thickness, the influence of the second load component is small. With a small relative thickness of the plate and a large ratio of the average medium pressure to the elastic modulus of the material, the influence of the second component of the transverse bending load becomes comparable to the bending stiffness of the plate. Linear bending and plate stability are considered. [ABSTRACT FROM AUTHOR]

When using local automatic control systems, the temperature and excess pressure of the hot gas in a chamber furnace are generally chosen independently, without regard for their interrelationships. At the same time, regulation of the fuel and air consumption involves changes in not only the temperature but also the pressure in the furnace chamber. That, in turn, changes the gas transfer with the surroundings and has a considerable influence on the temperature in the working chamber. As a result, the combustion of the gaseous fuel is excessive, and consequently furnace operating costs are increased unnecessarily. With constant volume of combustion products in such furnaces, control of the thermal power entails combining different components of the gaseous fuel with specified temperature in the working volume. On the basis of Bellman dynamic programming, the control of the heat-treatment cycle in the furnace may be optimized by selecting the optimal fuel composition (in terms of fuel cost) for each quantization period. The fuel cost is regarded as a linear function of the mean consumption of the individual fuel components in the quantization periods. Its minimum value for each instant is found by linear programming. An algorithm is developed for determining the optimal consumption of individual components of the gaseous fuel and also the consumption of the excess air, which is used in automatic control of the temperature and excess pressure of the hot gas within the working volume of the furnace. The proposed automatic control system not only permits optimization of the heating process in terms of the cost of the individual fuel components but also ensures autonomous control of the temperature and excess pressure of the hot gas in the working volume of the chamber furnace. With real-time control and cost optimization of the fuel components, the system is self-adjusting. [ABSTRACT FROM AUTHOR]

Vibrations in machines and their effect on performance are analyzed. One of the main sources of vibrations in machine parts is the slip bearing, in which the shaft passes through a bush with some gap. Impact arises when that gap closes. The operation of vibroprotective systems based on an elastic shock absorber is considered. The influence of the rigidity of the elastic element on the performance of slip bearings is analyzed. An elastic pneumatic element of increased rigidity is proposed, in the form of a cylinder with limited radial deformation. This element is able to center the shaft relative to the geometric axis of the bearing under the action of a radial load, thanks to the difference in contact area of the external surface of the bearing housing and the surface of the elastic cylinder. A method is developed for increasing the contact of the elastic element (the pneumatic cylinder with limited radial deformation) and the surface through which the external load is transmitted, with specified bearing parameters: the cylinder length; and the excess gas pressure within the cylinder. The shaft is assumed to fit in the bearing without a gap and the cylinder casing is regarded as inextensible. The deformation and rigidity of the elastic pneumatic cylinder with limited radial deformation are found to depend on the cylinder length and the excess gas pressure within the cylinder cavity. The mathematical formulas obtained permit the determination and specification of the parameters of the pneumatic element (the cylinder length and the excess gas pressure within the cylinder) as a function of the slip bearing's operating conditions. [ABSTRACT FROM AUTHOR]

This paper is based on a talk given at the Arterial Hemodynamics: Past, Present and Future symposium in June 2016. Like the talk it is divided into three different but related parts. Part 1 describes the calculation of reservoir and excess pressure from clinical pressure waveforms measured at 5 different aortic sites in 40 patients. The main results are that the reservoir pressure waveform propagates down the aorta and is effectively constant from the aortic root to the aortic bifurcation. Part 2 describes a low-frequency asymptotic analysis of the input impedance of an arterial tree. Neglecting terms of second order, the results show that the low-frequency component of the pressure waveform is uniform throughout the arterial tree and is delayed by an effective wave travel time that depends on the properties of the network. The low-frequency pressure waveform shares all of the properties of the reservoir pressure waveform, but it is premature to say that they are identical. Part 3 describes the analysis of arterial hemodynamicsusing wave fronts. It shows that every wave front introduced at the root of the aorta generates an exponentially increasing number of reflected and transmitted waves with exponentially decreasing amplitudes. The long-time response of the arterial tree can be described by a number of exponentially decaying eigen-modes, each with a different time constant. The analysis is applied to a 55-artery model of the human circulation and the modes and their time constants are shown. This theory provides an alternative method for studying arterial hemodynamics and helps in the interpretation of reservoir and excess pressure.

This paper is based on a talk given at the Arterial Hemodynamics: Past, Present and Future symposium in June 2016. Like the talk it is divided into three different but related parts. Part 1 describes the calculation of reservoir and excess pressure from clinical pressure waveforms measured at 5 different aortic sites in 40 patients. The main results are that the reservoir pressure waveform propagates down the aorta and is effectively constant from the aortic root to the aortic bifurcation. Part 2 describes a low-frequency asymptotic analysis of the input impedance of an arterial tree. Neglecting terms of second order, the results show that the low-frequency component of the pressure waveform is uniform throughout the arterial tree and is delayed by an effective wave travel time that depends on the properties of the network. The low-frequency pressure waveform shares all of the properties of the reservoir pressure waveform, but it is premature to say that they are identical. Part 3 describes the analysis of arterial hemodynamicsusing wave fronts. It shows that every wave front introduced at the root of the aorta generates an exponentially increasing number of reflected and transmitted waves with exponentially decreasing amplitudes. The long-time response of the arterial tree can be described by a number of exponentially decaying eigen-modes, each with a different time constant. The analysis is applied to a 55-artery model of the human circulation and the modes and their time constants are shown. This theory provides an alternative method for studying arterial hemodynamics and helps in the interpretation of reservoir and excess pressure. [ABSTRACT FROM AUTHOR]

Results are given for development of technology for electrolytic deposition of protective and electrical insulating ceramic coatings. The technology developed consists of combining microarc oxidation with imposition of excess pressure in a closed autoclave with the introduction of nanoparticles into the coating formation probe. [ABSTRACT FROM AUTHOR]

The agricultural sector is one of the most significant users of water resources worldwide. Irrigation infrastructure has been modernized in recent years in many regions dedicated to agriculture, transitioning from traditional open channels to more efficient on-demand pressurized irrigation networks. Despite improvements in water efficiency, the modernization of these networks has led to increased energy demands of the irrigation sector. Several negative consequences have been linked to additional energy requirements of pressurized networks, such as the rising cost of irrigation water. Other consequence linked has been the excess pressure in certain locations that could be used to recover energy from these networks. This paper studies the excess pressure in pressurized irrigation networks and the conversion of this excess to usable energy by means of small-scale hydropower turbines. Twelve irrigation networks located in the South of Spain have been modelled, quantifying the excess pressure available for power generation. Over 1 GWh per annum has been estimated that could be recovered.

The mechanical conditions for a volcanic eruption to occur are conceptually simple: a magma-driven fracture (normally a dyke) must be able to propagate from the source to the surface. The mechanics of small to moderate eruptions (eruptive volumes less than 10 km 3 ) is reasonably well understood, whereas that of large eruptions (eruptive volumes of 10–1000 km 3 ) is poorly understood. Here I propose that, while both large and small eruptions are primarily driven by elastic energy and may come from the same magma chambers and reservoirs, the mechanisms by which the elastic energy is transformed or relaxed in these eruptions are different. More specifically, during small to moderate eruptions, the excess pressure in the source (the primary pressure driving the eruption) falls exponentially until it approaches zero, whereby the feeder-dyke closes at its contact with the source and the eruption comes to an end. Under normal conditions, the ratio of the eruptive and intrusive material of the eruption to the volume of a totally molten shallow basaltic crustal magma chamber (at the common depth below the surface of 1-5 km) is about 1400, and that of a partially molten deep-seated basaltic magma reservoir (in the lower crust or upper mantle) is about 5000. Many magma chambers are partially molten, in which case the ratio could be close to that of reservoirs. Most magma chambers are estimated to be less than about 500 km 3 , for which the maximum eruptive volume would normally be about 0.4 km 3 . An eruptive volume of 1 km 3 would require a totally molten chamber of about 1400 km 3 . While chambers of this size certainly exist, witness the volumes of the largest eruptions, large eruptions of 10–1000 km 3 clearly require a different mechanism, namely one whereby the excess pressure is maintained during much of the eruption. I suggest that the primary excess-pressure maintenance mechanism is through caldera subsidence for shallow magma chambers and graben subsidence for deep-seated magma reservoirs. In this mechanism, it is the subsidence, of tectonic origin, and associated volume reduction (shrinkage) of the magma source that drives out an exceptionally large fraction of the magma in the source, thereby generating the large eruption. Most explosive eruptions that exceed volumes of about 25 km 3 , and many smaller, are associated with caldera collapses. The data presented suggest that many large effusive basaltic eruptions, in Iceland, in the United States, and elsewhere, are associated with large graben subsidences In terms of the present mechanism, successful forecasting of large eruptions requires understanding and monitoring of the volcanotectonic conditions that trigger large caldera and graben subsidences. [ABSTRACT FROM AUTHOR]

The direct effect of changes in applied total stresses on fluid-saturated geologic materials is reflected in fluctuations in pore pressure. The quantification of these pressure changes has traditionally been based on the classical poroelasticity theory, developed ignoring the natural variability in aquifer properties (parameters). Uncertainty of excess pore pressure prediction is therefore expected to be large when applying the classical model to field aquifer systems which generally have high degree of heterogeneity. Very limited attention to this issue has been paid. The motivation for this work is to quantify the uncertainty associated with the classical model, the spatial variability of the predicted excess pressure head in the field, where the groundwater flow is produced by the changes in total stress. The stochastic methodology used to develop the results of this study is based on the nonstationary spectral approach. It is found that the heterogeneity and correlation length scale of the log hydraulic conductivity process, and the pore compressibility parameter play essential roles in enhancing the variability in excess pressure head. In addition, the pore pressure head distribution predicted using the classical poroelasticity theory is subject to large uncertainty at a large depth in heterogeneous aquifers. [ABSTRACT FROM AUTHOR]

A fluid model for the formation of mantle plumes is proposed. During the emission of gas from the Earth’s core, it accumulates as lenses at the core-mantle boundary. Reaching a critical size, the lenses burst out into the mantle and migrate to the surface. A relatively stationary transmantle fluid flow from the core-mantle boundary arises, which heats the mantle and the layer interacting with it. The flow stops in the base of the hard lithosphere and spreads laterally, causing its melting accompanied by the formation of magma chambers, which, reaching critical sizes, massively intrude and flow out. [ABSTRACT FROM AUTHOR]

Kirkwood-Buff integrals are calculated from the thermodynamic data for binary mixtures of water with methanol, ethanol, 1-propanol, and 2-propanol at a temperature of 298.15 K in the pressure range from atmospheric to 100 MPa. The values of local compositions Δ n are calculated which characterize the excess (or deficit) of molecules i around the central molecule j. It is found that the pressure affects destructively the homoassociation in all mixtures studied. In a series MeOH < EtOH < 2-PrOH < 1-PrOH an excess of molecules around the similar type molecules increases in the local environment and the pressure effect on the local composition is enhanced. [ABSTRACT FROM AUTHOR]

Analytical formulas are developed for assessment of the influence of dusty air on the energy consumption in a hammer-type crusher applied to coal batch with a high content of fines. Analytical and experimental approaches are adopted. The ≤3 mm class present in the coal batch supplied for crushing forms a dust-air suspension, which is not crushed by hammer impact but significantly increases the drag on the rotor, with consequent increase in energy consumption. In overcoming the drag of the dust-air suspension, the energy consumption in the crusher may be 40% above the rated value. In that case, the removal of the ≤3 mm class from the feed to the crusher is necessary. [ABSTRACT FROM AUTHOR]