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Summary Mechanical impact stress on the vocal fold surface, particularly when excessive, has been postulated to cause the so-called phonotraumatic tissue lesions, such as nodules and polyps. The collision stress between the vocal folds depends on the vocal fold velocity at the time of impact. Hence this vocal fold collision speed is a relevant parameter when considering biomechanical economy of phonation, especially in voice professionals needing a louder voice than normal. Combining a precise photometric measurement of glottal area and simultaneous measurements of translaryngeal impedance (electroglottogram) for identifying the time of the maximum rate of increase of vocal fold contact allows computing the vocal fold collision speed in a wide range of loudnesses. The vocal fold collision speed is - for modal voicing - always smaller than the maximum vocal fold velocity during the closing phase, but it strongly increases with intensity. Moreover, this increase shows a biphasic pattern, with a significant enhancement from a certain value of dB on. Understanding physiological variables that influence vocal fold collision forces provides relevant insight into the pathophysiology and the prevention of voice disorders associated with phonotraumatic vocal hyperfunction.

In the production of magnesium hydride, hybrid Mg/H2 mixtures has a risk of explosion; therefore, systematic experiments were conducted to study its explosion characteristics and suppression. According to the results, the maximum rate of explosion pressure rise (dP/dt)max of hybrid Mg/H2 mixtures was more the twice than that of pure Mg. Five common explosion suppressants were individually added to hybrid Mg/H2 mixtures to inhibit dust explosion. Na2CO3, CaCO3, and (NH4)2HPO3 exhibited great inhibitory abilities for hybrid Mg/H2 mixtures explosion; however, melamine–cyanurate acid (MCA) and melamine polyphosphate (MPP) could stimulate the explosion. The mechanisms underlying MCA and MPP promotion of the hybrid Mg/H2 mixtures explosion were determined, namely the high concentration of flammable gases, such as ammonia, released after their thermal decomposition. These gases can ignite and intensify the explosion of hybrid Mg/H2 mixtures. This study provides a reference for reducing the risk in the H2 storage system of Mg.

Background There is no consensus on what dose of norepinephrine corresponds with futility. The purpose of this study was to investigate the maximum infusion and cumulative doses of norepinephrine associated with survival for patients in medical and surgical intensive care units (MICU and SICU). Materials and Methods A retrospective review was conducted of 661 critically ill patients admitted to a large academic medical center who received norepinephrine. Univariate, multivariate, and area under the curve analyses with optimal cut offs for maximum infusion rate and cumulative dosage were determined by Youden Index. Results The population was 54.9% male, 75.8% white, and 58.7 ± 16.1 y old with 384 (69.8%) admitted to the MICU and 166 (30.2%) admitted to the SICU, including 38 trauma patients. Inflection points in mortality were seen at 18 mcg/min and 17.6 mg. The inflection point was higher in MICU patients at 21 mcg/min and lower in SICU patients at 11 mcg/min. MICU patients also had a higher maximum cumulative dosage of 30.7 mg, compared to 2.7 mg in SICU patients. In trauma patients, norepinephrine infusions up to 5 mcg/min were associated with a 41.7% mortality rate. Conclusion A maximum rate of 18 mcg/min and cumulative dose of 17.6 mg were the inflection points for mortality risk in ICU patients, with SICU patients tolerating lower doses. In trauma patients, even low doses of norepinephrine were associated with higher mortality. These data suggest that MICU, SICU, and trauma patients differ in need for, response to, and outcome from escalating norepinephrine doses.

Methane explosion threats the safety in mining, gas recovery and the related downstream industry. The present study examined the suppression effect of KHCO3 (K) modified montmorillonite (K/MMT) inhibitor on reducing the hazard of methane/air mixtures explosion. The characteristic indices of explosion containing the maximum pressure (Pmax), the maximum rate of pressure rise ((dP/dt)max), the time of pressure peak arriving (tmax), were experimentally obtained in a standard 20 L explosion device. The hazard mitigating effect of each modified inhibitor was evaluated. which also elucidated the inhibition mechanism based on the characteristic parameters of K/MMT. Results showed that the K/MMT demonstrates better suppression effect than monomer inhibitor and the maximum decrease of Pmax (34.9 %) and (dP/dt)max (94.4 %) occurs when 45 wt% KHCO3 are loaded (45 wt%-K/MMT). When 45 wt%-K/MMT is used, 0.125 g/L is the optimal concentration to decrease KG to a minimum of 0.849 MPa m/s. This work presents an efficient modified inhibitor by using innovative technology, which is applied to mitigate or prevent disaster. The technology also provides theoretical support and technical guidance for the future development of inhibitors.

Zirconium powder, a main potential dangerous source in nuclear industry, has been focused on its explosion characteristics in this paper. Experiments were performed in a 20 L cylindrical explosion vessel with the influences of initial ignition energy, ignition delay time and zirconium concentration. Results showed that the maximum explosion pressure of zirconium-air mixture rose with the increase of the initial ignition energy, and a peak value was obtained with the variation of the ignition delay time. Lower explosion limit with the initial ignition energy of 10 kJ is 10 g/m³. Furthermore, explosion severity parameters, including maximum explosion pressure, maximum rate of pressure rise and maximum explosion index of zirconium-air mixture, were also obtained with the coupling variation between initial ignition energy and dust concentration. Research results and data obtained are a supplement to the utilization and safety operation of zirconium powders.

Dust explosions have been often reported in many industries that handle or process combustible dusts, with great losses to life and property. This explosion risk could be amplified under some extreme conditions like high-temperature environments. In this work, we develop a 2D numerical method to investigate explosion characteristics of corn starch cloud with an emphasis on the roles of high-temperature environments. The particle tracking trajectories and devolatilization evolution at high-temperature environments are described. The dust explosion severity characteristics including maximum explosion pressure (Pex) and maximum rate of pressure rise (dp/dt)max, are also investigated. In addition, the characterized devolatilization and explosion time are applied to analyze dust explosion behavior and flame propagation. The devolatilization evolution of dust cloud and flame propagation modes are found to vary with ambient temperature. And three ignition modes are observed after ignition. The simulation also provides a satisfactory prediction for dust explosion behavior at high-temperature environments.

Explosion characteristics of methylcyclohexane (MCH)-methanol- and toluene-methanol-air mixtures were investigated in a closed vessel at 0.1 MPa covering wide blending ratio range. The explosion hazard was evaluated by determining important explosion parameters. Comparisons were made between MCH- and toluene-air mixtures and the effects of methanol addition were identified. Results show that MCH-air yields approximate peak explosion pressure with toluene-air mixture but higher maximum rate of pressure rise. For the blend-air mixtures, the methanol addition exerts limited effect on the peak explosion pressure. For the maximum rate of pressure rise, the 20% methanol addition results in slight variation and further addition of methanol causes significant increase tendency. Regarding explosion phase parameters, toluene-air has longer explosion delay and burn period than MCH-air does. At the lean mixture side, the methanol addition generates slight decreases of explosion delay and burn period. At the rich mixture side, 20% methanol addition slightly extends the explosion delay and yields limited effect on the burn period. Further addition of methanol could significantly decrease the explosion delay and burn period simultaneously. Finally, the deflagration index was exponentially correlated with the explosion delay or burn period with the fitting constants listed.

Understanding and uncovering the mechanisms or motifs that molecular networks employ to regulate noise is a key problem in cell biology. As it is often difficult to obtain direct and detailed insight into these mechanisms, many studies instead focus on assessing the best precision attainable on the signalling pathways that compose these networks. Molecules signal one another over such pathways to solve noise regulating estimation and control problems. Quantifying the maximum precision of these solutions delimits what is achievable and allows hypotheses about underlying motifs to be tested without requiring detailed biological knowledge. The pathway capacity, which defines the maximum rate of transmitting information along it, is a widely used proxy for precision. Here it is shown, for estimation problems involving elementary yet biologically relevant birth-process networks, that capacity can be surprisingly misleading. A time-optimal signalling motif, called birth-following, is derived and proven to better the precision expected from the capacity, provided the maximum signalling rate constraint is large and the mean one above a certain threshold. When the maximum constraint is relaxed, perfect estimation is predicted by the capacity. However, the true achievable precision is found highly variable and sensitive to the mean constraint. Since the same capacity can map to different combinations of rate constraints, it can only equivocally measure precision. Deciphering the rate constraints on a signalling pathway may therefore be more important than computing its capacity.

The vertical movement is comprised of both vertical crustal movements and vertical ground movements. Vertical crustal movement is established by using a cubic polynomial model with first-order leveling data from four separate time periods (1958-2015) in the Shandong Province and neighboring areas, and the vertical motion is formed from continuously operating reference stations (CORS) data (2010-2015) with GAMIT/GLOBK and a linear regression estimation in the Shandong Province. Vertical ground movement can be obtained by subtracting vertical crustal movement from vertical motion. Vertical crustal movement of Shandong Province gradually changes from descending to ascending along the northwest to the southeast, and the rate varies from -5.9 to 6.2 millimeter/year (mm/yr). Three distinct settlement areas including Guangrao, Dezhou and Heze are analyzed in detail. Substantial subsidence with a maximum rate of 78.2 mm/yr occurred in northern and western areas of Shandong Province. Slight uplift with a maximum rate of 8.4mm/yr occurred in central region and Jiaozhou Peninsula of Shandong Province. The vertical ground movements are basically consistent with vertical movements in the Shandong Province.

The explosion characteristics of a hydrogen–propane mixture under different initial temperatures and at different hydrogen addition, equivalence, and dilution ratios were studied using a 20-L apparatus. First, the effects of hydrogen addition and equivalence ratio were studied. The results showed that the maximum explosion pressure and the maximum rate of pressure rise first increased, then decreased from lean to an equivalence ratio of 1.6, and reached the maximum value at the equivalence ratio of 1.2. The maximum explosion pressure and the maximum rate of pressure rise increased with the increasing hydrogen proportion of the mixtures, and the time to the maximum explosion pressure decreased. Furthermore, the mixed fuel with the equivalence and hydrogen addition ratios of 1.0 and 0.4, respectively, was explored under nitrogen or carbon dioxide dilution. Carbon dioxide exhibited a stronger dilution effect than nitrogen. For the mixed fuel with the equivalence and hydrogen addition ratios of 1.0 and 0.4, respectively, the maximum explosion pressure saliently decreased with the increasing initial temperature in the range of 25 °C-120 °C. The variation trend of experimental results was consistent with theoretical predictions.

Taking maximum flame propagation velocity, maximum explosion pressure, maximum rate of pressure rise and time-average of rising pressure impulse as index, this paper is aimed at evaluating the inerting effects of carbon dioxide on confined hydrogen explosion by varying initial pressure, carbon dioxide addition and equivalence ratio. The results indicated that under enhancing hydrodynamic instability, the stronger flame destabilization occurs with the increase of initial pressure. At Φ = 0.8 and Φ = 1.0, the destabilization effect of thermodiffusive instability continues to increase with the increase of carbon dioxide addition. At all equivalence ratios, the destabilization effect of hydrodynamic instability decreases monotonously with the increase of carbon dioxide addition. All of maximum flame propagation velocity, maximum explosion pressure, maximum rate of pressure rise and time-average of rising pressure impulse reach the peak value at Φ = 1.5, and decrease significantly with increasing carbon dioxide addition. The inerting effect of carbon dioxide could be attributed to the reduction of thermal diffusivity, flame temperature and active radicals. The chemical effect of carbon dioxide reaches the peak value at Φ = 1.0. With the increase of carbon dioxide addition, the chemical effect continues to decrease at Φ = 0.8 and Φ = 1.0, and increase monotonously at Φ = 2.5.

Experiments were performed to study the explosion characteristics of DME-blended LPG mixtures with different DME contents and equivalence ratios using a closed vessel. The maximum explosion pressure (Pmax), the maximum rate of pressure rise (dP/dt)max and the propagation velocity of shock wave (v) were investigated. The results indicated that both the peak overpressure and peak rate of pressure rise were raised with increasing DME content, reaching peak values at the equivalence ratio of 1.2. Furthermore, it was found that slight incorporation of DME had a small effect on the explosion hazard, but as the ratio of DME to LPG/DME mixture exceeded 30%, the explosion hazard would increase dramatically. The propagation of the shock wave behind the obstacle was divided into three stages in this paper: initial acceleration, stable acceleration and decaying. In the propagation process, Pmax, (dP/dt)max and v first increased and then decreased along the pipeline, and the peak values often appeared in the stable acceleration stage. The peak overpressure and the maximum value of v also appeared in the same location approximately, indicating that the occurrence of maximum overpressure risk was often accompanied with the appearance of the most severe dynamic evolution.

In this study, the explosion behaviors of methane-air mixtures were investigated experimentally in a cylinder vessel (210 mm inner diameter and 210 mm height) filled with a single orifice plate at atmospheric pressure (1 atm) and room temperature (298 K). The equivalence ratios of the test mixtures ranged from 0.7 to 1.3. The blockage ratios of the orifice plates were from 0.49 to 0.94, and the distance between the orifice plates and the ignition point ( S ) were 25 mm, 50 mm and 75 mm. The results show that the maximum explosion pressure in the presence of an orifice plate. However, the effects of the orifice plate on the maximum rate of pressure rise are various. At the fuel-lean side, the maximum pressure rise rate is increased significantly (larger than that of the stoichiometric condition). As the distance between the orifice plate and ignitor increases, the maximum pressure rise rate increases. In the case of the fuel-rich conditions, the maximum pressure rise rate is the smallest for S = 25 mm, followed by the no plate condition, S = 50 mm and S = 75 mm. The mechanisms are left for further study.

N-hexane is an important alternative fuel for aviation kerosene in recent years. In this study, experiments of n-hexane in air at various initial temperatures of 353–393 K, initial pressures of 60–100 kPa and equivalence ratio of 0.7–1.7 were carried out in a cylindrical vessel with central ignition. The pressure histories and outward propagations of the spherical flame in the explosion process were recorded by the pressure sensor and Schlieren system, respectively. Explosion characteristics including the explosion pressure Pmax, the maximum rate of pressure rise (dP/dt)max and laminar burning velocity U1 were obtained and analyzed. Results show that all explosion parameters strongly depend on the n-hexane/air ratio, initial pressures and temperatures. The explosion pressure Pmax and maximum rate of pressure rise (dP/dt)max raise with the increase in initial pressure and decrease in temperature. However, the dimensionless explosion pressure Pmax/P0 remains constant with an increased initial pressure. Furthermore, the n-hexane/air flame propagation characteristics were investigated and the Markstein length were studied. The unstretched flame propagation speed S1 and laminar burning velocity U1 share the similar variation tendency with equivalence ratios, and they are increased with the increase of initial temperatures and decrease of pressures.

In this paper, the Creation of Residual Strain during the hydration of cement paste is studied by performing oedometric experiments on class G cement pastes during the six first days of hydration. Various conditions of temperature (between 7 and 30 °C) and pressure (between 0.3 and 45 MPa) are explored. It is found that after a hydration degree of about 18%, mechanical loadings can induce residual strain. This state is reached at a time called critical time for Creation of Residual Strain (CRS). It corresponds to the maximum axial strain rate in an oedometric test or to the maximum rate of wave-velocity evolution versus time recorded in a Ultrasonic Cement Analyzer (UCA) test. The Boundary Nucleation and Growth (BNG) model is used to estimate the critical time for CRS. Within the range of studied temperatures and pressures, the predictive capacity of the BNG model for estimation of the critical time for CRS is demonstrated.

Explosion characteristics and influential factors of hybrid CH4/coal dust explosions are studied using a 20-L spherical explosion vessel. Experimental results show that the maximum explosion pressure and maximum rate of pressure rise increase in the initial phase and then decrease as the coal dust or CH4 concentration increases. The optimum concentrations of coal dust and CH4 are 200 g/m3 and 5 vol.%, respectively, when the initial pressure is equal to the atmospheric pressure. Moreover, the maximum explosion pressure keeps rising with the increasing initial pressure, and the maximum rate of pressure rise also shows an increasing trend. In addition, the optimum concentration of hybrid mixture varies with the initial pressure. The explosion risk of hybrid CH4/coal dust is much higher than that of pure coal dust in all dust concentrations, but it is only higher than that of pure coal dust explosion at high CH4 concentrations.

This article reports the results of an experimental study on explosion characteristics of gasoline vapor/air mixture in closed vessels with different shapes and volumes (20-L sphere, 280-L rectangle, 1.15 m3 cylinder and 5.19 m3 cylinder) and different shapes but same volumes (straight rectangular tube and rectangular tubes with 1 branch, 2 branches, 3 branches and 4 branches) under conditions of low, medium and high initial gasoline vapor volume concentration. The maximum explosion overpressures pmax, the maximum rates of pressure rise (dp/dt)max and the deflagration indices KG are examined in comparison with similar data obtained in different shape and size vessels. The measured maximum rates of pressure rise and deflagration indices are strongly influenced by the shape and size of test vessels. When the other initial conditions are invariant, the maximum rates of pressure rise and deflagration indices in the spherical vessel are larger than that in rectangular tube and cylinder tube. When the vessel shapes are same or similar, with the increase of the vessel volumes, the maximum rate of pressure rise decreases, while, the deflagration index increases. When the test vessels remain same size but different shape, the maximum overpressure and maximum rates of pressure rise of the gasoline vapor explosions increased with the branch number of the rectangular tubes. The influence of flame velocity, structure and shape and even turbulence should be considered when the maximum rate of pressure rise and deflagration index of the explosions in a specific non-spherical vessel are determined.

To study the effects of hydrogen addition on the explosion characteristics (the explosion pressure and maximum rate of pressure rise) of n-hexane/air mixtures, experiments were performed in a cylindrical vessel at 100 kPa, 353 K, with equivalence ratios of 0.8–1.7 and hydrogen addition range from 0% to 80%. Concurrently, flame images were captured by high-speed schlieren photography to study the burning performance. The results indicate that both the explosion pressure and maximum pressure rise rate increase with the increase in hydrogen addition in terms of the lean n-hexane/hydrogen/air mixtures. With respect to the richer mixtures, however, the inverse tendency is observed. With increasing hydrogen fractions, the explosion pressure and maximum pressure rise rate decrease. The peak values of the explosion pressure and maximum pressure rise rate shift to the leaner mixture with increased hydrogen proportion. Moreover, the laminar burning velocities of n-hexane/hydrogen/air mixture were also obtained via the expanding spherical method and the pressure-time histories, respectively. Variation of laminar burning velocity with hydrogen proportion from both methods were studied as well, and the results show that the laminar burning velocity changes significantly under different hydrogen addition.

Bio-H2 was produced by Enterobacter sp., using de-oiled cake (DOC) as nitrogen source and was subsequently converted to electricity by a hybrid platform of proton exchange membrane fuel cell (PEM-FC) and photo voltaic (PV) cells. Taguchi design was used to maximize H2 production on using different DOC concentrations, pH, pre-treatment time and agitation speeds. Highest H2 production of 3.42 ± 0.26 L L−1 was observed at pH 6.0, 50 g L−1 DOC concentration, 20 min pre-treatment time and 200 rpm agitation speed, respectively. In continuous process maximum rate of H2 production of 854 ± 20 mL L−1 h−1 (molasses), 580 ± 22 mL L−1 h−1 (glucose) and 640 ± 22 mL L−1 h−1 (starchy wastewater), respectively was observed at 0.2 h−1 dilution rate. The hybrid system showed maximum current (I), voltage (V) and power (P) of 0.035 mA, 11 V and 385 mW, respectively.

In this paper, the explosion characteristics of a methane-air mixture at low initial temperatures (up to 113 K) and elevated pressures were measured. Various parameters, such as explosion pressure, rate of the explosion pressure rise, combustion duration and flame development duration were obtained for the initial temperature range of 123–273 K. The results indicated that the maximum explosion pressure and the maximum rate of explosion pressure rise reached peak values at the equivalence ratio of 1.1. With the increase in initial pressure, the maximum explosion pressure increased significantly, and the maximum rate of explosion pressure rise increased linearly because of a larger density of the flammable mixture within the explosion vessel. With the decrease in the initial temperature the maximum explosion pressure increased monotonically, whereas the effect of initial temperature on the maximum rate of explosion pressure rise was negligible because of two opposing aspects: an increase in the amount of flammable mixture and a decrease in the flame propagation speed. Both the combustion duration and the flame development duration increased with the increase in initial pressure and decreased with the increase in initial temperature. Finally, at an equivalence ratio of 1.0, two empirical correlations were obtained to calculate the combustion duration and the flame development duration.

Nowadays the quantification of the content of genetically modified (GM) constituents in food or feed products is performed by using either quantitative real-time PCR (qPCR) or digital PCR (dPCR). The latter is increasingly used. Therefore, experimental protocols for the quantification of 52 GM events authorised in the EU have been converted into a digital format and minimum performance characteristics for dPCR methods are detailed. Because of the need to harmonise the transformation of PCR results between two different measurement scales, 50 conversion factors for Certified Reference Materials (CFCRM) have been experimentally determined by three and sometimes four independent expert laboratories. The uncertainty of each CFCRM has been estimated to express dPCR results in mass fraction with a consistent uncertainty contribution. In 38 out of 58 cases, the validated qPCR methods (for 52 event-specific and 6 taxon-specific measurements) could easily be transferred into dPCR methods by using the same oligo sequences, final oligo concentration or annealing temperatures for the dPCR procedure. Laboratories have nevertheless used different strategies to improve the resolution or to reduce the so-called rain in their dPCR outcome. Those modifications were needed for PCR procedures that could not be converted without changes into a digital format. Therefore, exclusion/quality criteria such as the maximum rate of partitions with intermediate fluorescence “rain”, the minimum resolution and repeatability are suggested for dPCR methods. The CFCRM determined in this study were generally in agreement with the declared zygosity of the GM parental donor for hemizygous maize events. In a limited number of GM events the CFCRM values were significantly different when measured with different maize-specific (ZmAdh1 or hmgA) genes.

Coal dust explosion occurs violently at the atmosphere of coal gasification due to the combustible gas addition. To reduce the risk of dust explosion, a composite inhibitor with the combination of zeolite and carbamide was prepared and characterized. And the inhibition effects of the composite inhibitor with different mass fractions on the explosion pressure and flame propagation velocity were studied in a 20 L explosion spherical vessel, which were compared with that of carbamide and zeolite. The results indicate that the composite inhibitor showed an irregular morphology with the carbamide particles covered on the porous zeolite carrier by the bonding of agar. The best inhibition effect was reached for the composite inhibitor of carbamide and zeolite with the ratio of 1:1. And when the 50 wt% optimum composite inhibitor was added in the coal dust, the maximum explosion pressure and maximum rate of explosion pressure rise were reduced by 0.42 MPa and 23.871 MPa/s with the flame propagation velocity decreasing of 0.690 m/s. Furthermore, the inhibition mechanism of the composite inhibitor was presented by analyzing the samples and explosion residues.

Coating of nanoscale flow aids is widely used in pharmaceutical applications to increase the flowability of cohesive powders. For combustible pharmaceutical active ingredients and excipients, it is unclear whether increased flowability affects the dust explosion hazard. In this work, acetaminophen (APAP) and microcrystalline cellulose (MCC) were studied with and without a coating of silica nanoparticles. A full set of explosion parameters for the pure materials and their flow-improved mixtures was determined in accordance with ASTM standards. The results show that parameters including minimum ignition temperature, minimum explosible concentration, and maximum explosion pressure were independent of powder flow properties, while the presence of flow aids led to significantly lower minimum ignition energy values for both APAP and MCC, and a slightly higher maximum rate of pressure rise for APAP. The connection between dust flowability and the dust explosion hazard is discussed with respect to these experimental results.

Evaluating the critical safety temperature of nitrocellulose is necessary to reduce the possibility of nitrocellulose accidents (thermal explosion and fire) and to implement effective loss prevention. In the present study, isothermal and non-isothermal experiments were performed on different forms of nitrocellulose using a differential scanning calorimeter. A scanning electron microscope was utilized to detect the aging process of nitrocellulose under different constant temperatures. Thermodynamic parameters were simulated by thermal safety software, and the results indicated that autocatalytic simulation rather than nth order simulation was applicable to assess the apparent activation energy of nitrocellulose samples. Moreover, iso-conversional methods, including Kissiger–Akahira–Sunose, Ozawa–Flynn–Wall, Friedman, Tang et al. and distributed activation energy model methods, were employed to validate the simulated activation energy. The average activation energy calculated by the five iso-conversional methods was lower than that simulated by autocatalytic simulation. Moreover, critical storage temperatures, including the time to maximum rate and the time to conversion limit, were evaluated. It was found that the critical storage temperatures of nitrocellulose in white chip form were lower than that of nitrocellulose in white silky fibre form. Finally, the critical thermal explosion temperatures of two samples were calculated, and it was concluded the temperature of nitrocellulose in white silky fibre form was about 5.0 °C higher than that of nitrocellulose in white chip form.

Electrochemical and SCC behaviour of X70 pipeline steel samples were investigated under various AC frequencies to elucidate the mechanistic aspects of the alternating current (AC)-assisted stress corrosion cracking (SCC) of pipeline steels in simulated seawater solutions. Results indicate that AC serves as a critical influencing factor on SCC of X70 pipeline steel by accelerating the mass transfer and in-situ-O2-generation, and hydrogen evolution due to the non-Faraday and Faraday potential of AC, respectively. The electrochemical reactions show a maximum rate around 30 Hz, which is attributed to the periodic effect of AC frequency on the different processes; a similar trend is observed in SCC behaviour with increase in AC frequency. AC catalyses both the anodic dissolution (AD) and hydrogen evolution reactions, and greatly increases the SCC susceptibility resulting from the combined effect of increased AD and hydrogen embrittlement (HE) on the SCC process.

In this study, the explosive behavior of syngas/air mixtures was investigated numerically in a 3-D cylindrical geometric model, using ANSYS Fluent. A chamber with the same dimensions as the geometry in the simulation was used to investigate the explosion process experimentally. The outcome was in good agreement with experimental results for most equivalence ratios at atmospheric pressure, while discrepancies were observed for very rich mixtures (ϕ > 2.0) and at elevated pressure conditions. Both the experimental and simulated results showed that for syngas/air mixture, the maximum explosion pressure increased from lean (ϕ = 0.8) to an equivalence ratio of 1.2, then decreased significantly with richer mixtures, indicating that maximum explosion pressure occurred at the equivalence ratio of 1.2, while explosion time was shortest at an equivalence ratio of 1.6. Increasing H2 content in the fuel blends significantly raised laminar burning velocity and shortened the explosion time, thereby increasing the maximum rate of pressure rise and deflagration index. Normalized peak pressure, the maximum rate of pressure rise and the deflagration index were sensitive to the initial pressure of the mixture, showing that they increased significantly with increased initial pressure.

Vented hybrid mixture explosions were conducted in a 20-L chamber with different venting diameters and static activation pressures. Simultaneously, the maximum explosion pressure and the maximum rate of pressure rise of hybrid mixtures were also determined. It was found that the addition of methane to lycopodium dust led to an increase in both the maximum explosion pressure and the maximum rate of pressure rise and a decrease in the optimum dust concentration. Both the maximum explosion pressure and the maximum rate of pressure rise of hybrid mixtures were higher than those of lycopodium dust, but lower than those of methane. Similarly, the addition of methane to lycopodium dust led to an increase in the maximum reduced pressure, and the maximum reduced pressure increased with increase of the methane concentration. This effect was more pronounced for small vents and high static activation pressures. The maximum reduced pressure of the hybrid mixture was higher than that of lycopodium dust, but lower than that of methane. This was consistent with the relationship of the maximum explosion pressure between the three different systems. However, the increase in the maximum reduced pressure of lycopodium dust taken by the additional methane was obviously higher than that in the maximum explosion pressure, indicating that the influence of methane on the maximum reduced pressure of lycopodium dust was more significant. Adding methane to lycopodium dust increased the longest vented flame length and decreased the duration time of the external flame. Similar to the maximum reduced pressure, the longest flame length of the hybrid mixture was longer than that of lycopodium dust, but shorter than that of methane. However, it is the converse for the duration time of the external flame.

The impact of nitromethane on the explosion characteristics of diethyl ether -aluminium powder mixed fuel in the presence of different ambient factors is studied in a 20 L sphere-shaped explosion vessel. The explosion pressure of the fuel is obtained by a series of experiments, and the mechanism of nitromethane during these experiments is deduced by analysing the maximum rate of pressure increase and the gas products. The results showed that a synergistic effect existed between nitromethane and diethyl ether at high mass concentrations. The self-decomposition reaction of nitromethane enables high mass concentration fuels to react more fully, maintaining a higher explosion pressure under a low-pressure or high-relative humidity environment.

Research Objectives To identify changes in handrim kinetics and propulsive stroke patterns over time in pediatric manual wheelchair users. Design Longitudinal, prospective. Setting Motion Analysis Lab at Shriners Hospital for Children- Chicago. Participants Six pediatric manual wheelchair users with spinal cord injury. To be eligible, participants were required to be under 21 years of age during their first visit and use a manual wheelchair as their primary mode of mobility. Interventions Participants were evaluated in two separate data collection sessions, approximately one year apart. Participants propelled their wheelchair along a 15-meter, tile walkway at a self-selected speed and stroke pattern for multiple trials while kinetic and kinematic data were collected using a Vicon motion capture system and a Smartwheel affixed to their personal wheelchair. Main Outcome Measures Handrim peak force, variance of force, and stroke patterns. Results Over half of the participants increased their maximum rate of rise (F/t) of resultant force between visits. No trends were observed in the change in average peak resultant force per stroke cycle between visits, though one participant had a large decrease and another had a large increase. The variance of peak resultant force decreased notably in the three oldest participants and decreased in the three youngest participants. The number of types of stroke patterns used for propulsion and the frequency with which each pattern was used changed for all but one participant between visits. Conclusions Changes in handrim kinetics and stroke patterns were observed in most participants between visits. This is concerning, as some of these changes, such as decreased variance of peak resultant force and increased maximum rate of rise, have been correlated with shoulder pain and pathology in adults. Additional research using a larger cohort of pediatric manual wheelchair users is indicated to observe changes that could lead to musculoskeletal pain and pathology. Author(s) Disclosures None.

Rising sea levels pose a potential threat to the densely populated areas along the Indian coastline and the low-lying islands, and cause disastrous impacts to coastal and offshore structures. Large fluctuations in sea surface temperature (SST) in the North Indian Ocean (NIO) is one of the contributing factors in inducing significant changes in sea level along the Indian coastline. Therefore, it is important to quantify the trends in sea level rise (SLR) in association with SST in this region. In this study, the seasonal climatology and variability of sea level anomaly (SLA) and SST is examined in the NIO (65 °E–92.5°E, 4.5 °N–25 °N). A comparative study is conducted based on two different datasets by using the reconstructed sea surface height anomalies (SSHA) for 58 years from 1952–2009 and Archiving, Validation and Interpretation of Satellite Oceanographic (AVISO) SLA dataset for 27 years from 1993–2019.The spatial correlation maps between SLA and SST reveal that AS exhibits strong positive correlation as compared to BoB throughout the year. In addition, the rate of increase in sea level is examined at twelve locations along the Indian coastline for pre-satellite era (1952–2009) and satellite altimeter era (1993–2019). In recent decades, a higher rate of increase as compared to long term trends (1952–2009) is observed, i.e., even exceeding the global mean SLR trend (3.2 mm yr −1). The highest rate of increase in annual sea level is observed at Mangalore ( r = 0 . 4 cm) and the lowest is observed at Haldia ( r = 0 . 03 cm) during the recent decades. However, during 1952-2009, the maximum rate of annual SLR is found at Okha ( r = 0 . 21 cm) and the minimum at Vishakhapatnam ( r = 0 . 11 cm). The analysis clearly elucidates that the sea level is continuously rising and accelerating and, four Indian coastal cities, namely, Vishakhapatnam, Mangalore, Mumbai and Chennai are the most susceptible of all.

This study presents results pertaining to bioH 2 production carried out in batch experiments under different inorganic acid pretreatments of sludge. The sludge was collected from an anaerobic digester and was subjected to different acid (H 2 SO 4 , H 3 PO 4 , HNO 3 , and HCl) pretreatments at pH 3 for 24 h. The results showed that electron equivalent balance closure was within −12 to +10% for all experiments; the portion of electrons as bioH 2 fluctuated from 16% to 25%. H 2 SO 4 pretreatments significantly increased H 2 yields to 3.3 mol H 2 /mol glucose followed by HNO 3 , HCl, and H 3 PO 4 pretreatments which averaged 2.5 ± 0.5. Enthalpy (ΔH°) and Gibb’s free energies (ΔG°) fluctuated from 120.5 to 192.7 (kJ/mol) and from −2.2 to −5.9 (kJ/mol). The modified Gompertz was assessed and determined that the maximum bioH 2 production potential, 1551 mL and maximum rate of bioH 2 production, 303 mL/h occurred using the H 2 SO 4 pretreatment.

Explosion always occur in turbulent ambience, but few researches focusing on the effects of turbulence on explosion characteristics has been performed in the current. In the present investigation, the effects of initial turbulence on the explosion characteristics of stoichiometric and rich hydrogen-air mixtures were experimentally studied and analyzed on the basis of explosion pressure traces. Maximum explosion pressure, explosion duration, maximum rate of pressure rise, fast explosion duration, deflagration index, and the averaged heat flux through the wall during explosion were systematically examined. The results indicated that, turbulence will reduced the corresponding equivalence ratio to maximum rate of pressure rise but won’t change the corresponding equivalence ratios to maximum explosion pressure and two explosion durations. In turbulent ambience, two explosion durations will decline for the accelerated propagation of pressure wave, the values of maximum explosion pressure and maximum rate of pressure rise will be raised for the reduced heat flux through the vessel’s wall during explosion. In addition, turbulence raises the value of deflagration index, namely it raises the hazardous level.

Effect of structure on sodium release of model solid lipoproteic colloids (SLCs) was investigated. The SLCs structures were varied by different levels of protein (8 and 16%, w/w), fat (0, 11, 22, and 33%, w/w), NaCl (1.5% and 3.5%, w/w), and homogenization pressure (14 and 55 MPa). Sodium release was measured while the SLCs were compressed in water. For SLCs with 1.5% and 3.5% NaCl, the porosity correlated positively with the maximum rate of sodium release. For the SLCs with 3.5% NaCl, the particle size of fat correlated negatively with the maximum concentration of released sodium and the area under the curve of sodium release profile. This study revealed that sodium release can be controlled via the convective transfer or diffusive transfer mechanisms by controlling the porosity and particle size of fat, respectively.

A differential thermal analysis (DTA) based method is used to estimate the temperature range for crystal nucleation in BaO·2SiO2 and 5BaO·8SiO2 glasses. For the BaO·2SiO2 glass, the temperature range for significant nucleation is approximately 660 °C to 770 °C, with a maximum rate near 712 °C. These results are in good agreement with those determined from traditional two-step annealing, microscopy-based studies. Having verified the DTA approach with this glass, the method is used to study the 5BaO·8SiO2 composition, for which nucleation data do not exist. The temperature range for significant nucleation is found to be slightly higher than in the BaO·2SiO2 system, approximately 675 °C to 790 °C, with a maximum rate near 725 °C. Measurements of the peak height, peak temperature, and peak area are used to determine the temperature where growth starts to overlap significantly with nucleation. The peak height appears to be the more sensitive indicator for determining this.

Experiments were systematically performed in a standard 20-L spherical vessel to measure the explosion parameters of different methane-ethane/air mixtures. Data were scrutinized and carefully compared to elucidate the explosion characteristics. Firstly, it turns out that ethane has higher maximum explosion pressure, Pmax and maximum rate of pressure rise, (dP/dt)max than methane in air against the equivalence ratio. The Upper Flammability Limit, UFL (in equivalence ratio) of ethane in air is also larger; while the Lower Flammability Limits, LFLs (in equivalence ratio) of both gases in air are almost the same. Then for methane-ethane mixtures, when the ethane content increases, the value of Pmax versus equivalence ratio and the UFL both rise as well; while the LFL changes little if taking the uncertainty of measurement into account. Similarly, (dP/dt)max increases together with growing ethane content in the fuel mixture at the same equivalence ratio, especially at the fuel-rich side; but at the fuel-lean side the discrepancies are relatively smaller. In general, due to the higher reactivity, exothermicity and laminar flame speed of ethane, it can remarkably raise the explosion pressure, pressure rise rate and flammable range, and ultimately enhance the explosion risk and severity of fuel blend system.

The aim of this study is to obtain the optimum design of geothermal heat pump aided district heating system ( GHPDHS ) by using a novel ANN model that composed of multistage with multilevel. For this purpose, the acquiring of the best design were performed by utilizing the back-propagation learning algorithm with three different variants which were Levenberg-Marquardt ( LM ), Pola-Ribiere Conjugate Gradient ( CGP ), and Scaled Conjugate Gradient ( SCG ). In this aim, the proposed ANN model was mainly formed from two stages. The first one has a single level whereas the second one composed of three levels in this new ANN model. According to results, the maximum rate of the error occurred in the Pump 2 as % 3.0092 and the minimum of that was obtained from COP sys with % 0.0018. The best R 2 value of the third level of the second stage network structure was calculated as 1 for LM -20. As a consequent, this study showed that the multistage with multi-level ANN model could be easily applied to other energy systems in order to save more time and simplicity.

We adopted 106 campaign-mode GPS observations and 310 precise leveling measurements between 2002 and 2010 to understand the present-day crustal deformation in mudstone area and to estimate the earthquake potential of the Hsiaokangshan (HKSF) and the Chishan faults (CHNF) in southwest Taiwan. Horizontal velocities east of the CHNF are ~ 66 mm/yr, 270° and gradually decrease westward to ~ 15 mm/yr, N259°. A horizontal velocity gradient of ~ 15 mm/yr is shown between the HKSF and CHNF. Subsidence rates west of the HKSF and east of the CHNF are ~ 5–10 mm/yr, while the uplift is observed between these two faults in the highest elevation with the maximum rate of ~ 18 mm/yr. The observed deformation patterns are difficult to be fully modeled by 2D kinematic fault model. Field relationships within the vertical shear zones of the mudstone therefore indicate that the deformation pattern may be also controlled by a relic onshore mud diapir that is still experiencing vertical uplift. Consistency between the geological and geodetic vertical velocities, weak rock strength, and no destructive earthquakes over the last 100 years imply that faults (HKSF) within the mudstone area are creeping. However, the CHNF or the associated decollement may still have earthquake potential.

The potential of achieving effective utilization for a given coal using maceral separation is dependent on the differences in thermal characteristics of its maceral concentrates. In this paper, vitrinite-rich and inertinite-rich concentrates were obtained from five bituminous coals with R random ranging from 0.64% to 1.73% using a float-sink procedure. The devolatilization characteristics and kinetics of maceral concentrates were investigated using thermogravimetric analysis at the heating rate of 8 °C/min − 1 from 50 °C to 1200 °C. The devolatilization is comprised of three regions characterized by different weight loss rates. During principal devolatilization, inertinite-rich concentrates are characterized by similar initial temperature, slight greater temperature of maximum rate of weight loss, and greater terminal temperature. The maximum rate of weight loss and the index of volatile matter released decrease with an increase in rank; the lower the rank, the greater the differences between vitrinite-rich and inertinite-rich concentrates. The principal devolatilization displays the greatest apparent activation energy, followed by post-principal devolatilization, and the least for initial devolatilization. During principal devolatilization, the apparent activation energy difference of vitrinite-rich and inertinite-rich concentrates is higher in lower-rank coal and becomes almost zero at the R random of 1.73%. The minimum activation energy and apparent activation energy were in detail discussed.

This paper presents a detailed investigation of the explosion characteristics (i.e., maximum explosion pressure, maximum rate of the pressure rise) and combustion properties (i.e., laminar burning velocity, turbulent burning velocity) of diethyl ether (DEE)/air mixtures under different pre-ignition quasi-isotropic turbulence velocity. The concentration of DEE/air mixtures is the equivalence ratio ϕ = ~1.1. The experiment is performed by systematically measuring the pressure evolutions in a 20-L explosion spherical vessel. The present measurement shows that the peak explosion pressure (Pmax) increased nonlinearly with increasing pre-ignition turbulence velocity. The peak pressures reach the maximum values of 0.93 MPa at pre-ignition turbulence velocity 6.2 m/s, and the lowest are 0.57 MPa at pre-ignition turbulence velocity 1.0 m/s. The experimental result of the laminar burning velocity ( u L ) is ~ 0.55 m/s, and the largest data of turbulent burning velocity ( u t ) are 1.8 m/s at pre-ignition turbulence velocity at 6.2 m/s. In this work, the model gives the expression on the laminar burning velocity ( u L ) and turbulent burning velocity ( u t ) versus the pre-ignition turbulence velocity U rms in accordance with Williams's theoretical model.

The explosion characteristics of hydrogen-air mixtures in a wide range of equivalence ratios in closed vessels were investigated experimentally. The maximum explosion pressure, maximum pressure rise rate (along with deflagration index), explosion time and heat loss were evaluated. Three vessels with low asymmetry ratios ( H / D ) of 0.146, 0.244 and 0.341 were used to study the effect of vessel height on explosion parameters, in which H and D are the height and inner diameter of the vessel, respectively. In the H / D = 0.341 vessel, the effect of ignition position on explosion behaviors was also considered. The results show that, with the increase of the vessel height, the maximum explosion pressure increase correspondingly, and the explosion time decreases orderly. In the lowest height vessel ( H / D =0.146), the ignitor-regulating column acts as a ‘turbulence-generator’. Thus, the maximum rate of pressure rise could be increased significantly while the heat loss could be decreased. Compared with the central ignition scenario, both the maximum explosion pressure and maximum pressure rise rate are decreased for the asymmetrical ignition; meanwhile, the explosion time and the heat loss during the explosion are increased.

The flammability of refrigerants is a major cause of refrigerant explosion incidents. Studying the explosion characteristics of refrigerants at different initial temperatures can provide significant benefits for solving the safety problems of refrigerants under actual working conditions. This paper studied the effects of the initial temperature and refrigerant concentration on the explosion characteristics of refrigerant 2, 3, 3, 3-tetrafluoropropene (R1234yf) at 0.1 MPa. The curves of explosion characteristics with different initial temperature revealed the same variation trend ranged from 25 °C to 115 °C. Specifically, as the refrigerant concentration was raised, the peak overpressure, the maximum rate of pressure rise, and laminar burning velocity increased initially and decreased afterwards, along with maximum values at the refrigerant concentration of 7.6%. When the refrigerant concentration was 7.6%, the peak overpressure declined exponentially with the initial temperature rise, while the maximum rate of pressure rise increased linearly. The laminar burning velocity calculated from the spherical expansion method indicated that the flame propagation was gradually accelerated by the increase of initial temperature, which coincided with the change of the maximum rate of pressure rise. Meanwhile, experiments and CHEMKIN simulation results demonstrated the effects of elevated temperature from 20 °C to 50 °C on the explosion limits of R1234yf. The lower explosion limit reduced and the upper explosion limit increased with rising initial temperature. In general, R1234yf exhibited moderate combustion and lower explosion risk, compared with traditional refrigerants.

Creep behaviors of a 3rd generation single crystal superalloy DD33 at 1100 °C/1120 °C/1150 °C and 120 MPa have been characterized. The role of topological inversion and dislocation structures during tertiary creep have been studied. It is found that the tertiary duration is inversely related to the creep temperature. The higher the temperature is, the faster the tertiary creep rate rises and the higher the maximum rate is. The topological inversion level also shows a negative correlation with the temperature and the γ/γʹ inversion cannot account for the rapid increase in the tertiary rate. The formation of γʹ-junctions and the diffusion of γ/γʹ-forming elements result in the phase inversion, which strongly depends on the tertiary duration. Moreover, with the temperature increases from 1100 °C to 1150 °C, the main mobile dislocations are the long straight a superdislocations, the individual screw a superdislocations and the interface-deposited 60° dislocations, respectively. The factors affecting the tertiary creep rate have been analyzed in detail.

Objective This study evaluated physical and mechanical properties and characterized the filler particles of seven composites. Materials and methods Filtek Supreme (FS, 3M Oral Care), Forma (FO, Ultradent), Charisma Diamond (CD, Kulzer), Spectra Smart (SS, Dentsply), Filtek Bulk Fill (FB, 3M Oral Care), Tetric N-Ceram Bulk Fill (TB, Ivoclar), and Cention N (Ivoclar) in self- (CNSC) or dual-curing (CNDC) were evaluated. Fillers size, shape, and content were analyzed by scanning electron microscopy (SEM) and X-ray dispersive energy spectroscopy (EDX). Disk-shaped specimens (n = 5) were prepared for sorption (SP) and solubility (SL). Flexural strength and elastic modulus were tested at 24 h and 12 months (n = 10). Degree of conversion (DC%) and maximum rate of polymerization (Rpmax) were evaluated using micro-Raman spectroscopy. SP and SL results were submitted to Kruskal-Wallis one-way ANOVA and Dunn's pairwise test (α = 0.05). Mechanical properties were analyzed by 2-way ANOVA and Tukey's test (α = 0.05). DC% of CNSC and CNDC was compared by independent t-test (α = 0.05). Rpmax results were analyzed by 1-way ANOVA and Tukey's test (α = 0.05). Results The composites differed regarding filler size, shape, and content. CD and CNSC showed lower SP than FS. SS had lower SL than CNSC and CNDC. CNDC presented higher DC% than CNSC. CD, TB, and CNDC showed the highest Rpmax. TB, CNSC, and CNDC showed the lowest 24-h flexural strengths. Mechanical properties of CD did not decrease, while FO, TB, and CNSC showed a significant reduction after storage. Conclusions Monomer composition and fillers characteristics greatly influenced the physico-mechanical properties of the tested composites.

The present work aims to provide theoretical support to prevent LPG explosion accidents and reduce its hazardous effect. The explosion of LPG-air mixtures (4.0 % – 9.0 % in volume) under N2 and CO2 dilution (0.0%–30.0% in volume) was experimentally investigated by using a 20-L vessel at ambient temperature and pressure. The parameters of the maximum explosion pressure ( p m a x ), time to reach the maximum explosion pressure ( t c ), maximum rate of the pressure rise ( ( d p / d t ) m a x ), time to reach the maximum rate of the pressure rise ( t b ), and average velocity of flame propagation ( v ) were investigated. In addition, the inerting efficiencies of N2 and CO2 were compared and analyzed. The results show that there exists a cubic function relation among p m a x , ( d p / d t ) m a x x, t c , t b and LPG volume fraction during the LPG explosion process. At the volume fraction of LPG was 5.7 %, all parameters reached peak values. The addition of N2 and CO2 effectively suppressed the explosion of LPG, reduced p m a x , ( d p / d t ) m a x , and v and extended t c and t b . At a low LPG volume fraction, the inerting efficiency of CO2 was higher than that of N2. At a high LPG volume fraction, the inerting efficiency of N2 was higher than that of CO2.

The overpressure and flame propagation of hydrogen/aluminum dust hybrid explosions are studied in a 5-L square closed vessel. Aluminum dust was mixed with hydrogen with concentrations of 0%–30%. The results show that there are certain hydrogen concentrations that affected the changing trend of the maximum pressure rise Pex and the maximum rate of pressure rise (dP/dt)ex. When the hydrogen concentration is lower than the certain concentration, the Pex and the (dP/dt)ex are approximately equal to those of pure aluminum dust. When the hydrogen concentration is higher than the certain concentration, the Pex and the (dP/dt)ex increase notably. As the hydrogen concentration increase to more than 20%, the flame front separation can be observed. The addition of hydrogen can significantly affect the ignition delay time and the flame propagation velocity of the hybrid mixtures. There are three stages in the relation of the maximum flame propagation velocity vmax with the hydrogen concentration: in the first stage, the vmax is almost equivalent to that of pure aluminum dust. In the second stage, the vmax increases slightly. In the third stage, the vmax increases significantly, which can exceed more than 50 times the vmax of pure aluminum dust.

In this work, we describe the atomic effects of graphene nanosheets adding to the hydraulic fracturing process by molecular dynamics method. In our simulations, we study the nanosheets type effect on the fracturing process. For this purpose, we reported physical parameters such as temperature, potential energy, joint force, and the number of lost atoms from atomic substrates. In our approach, nanofluid, which used in hydraulic fracturing, is exactly simulated by various interatomic force fields. Our simulations show that adding graphene nanoparticles to the first fluid causes maximum atomic removal from simulated rock substrate. Numerically, after 2.5 ns, the departed atoms from rock substrate reach to 74 atoms. Furthermore, the atomic rate of graphene nanosheets is another important parameter in hydraulic fracturing. Our molecular dynamics results show that, by 5% atomic rate of graphene nanosheets to initial fluid, the departed atoms reach to the maximum rate (101 atoms). Finally, by adding graphene nanosheets with 4 nm length, the top quality of particles departed from the rock substrate.

In this work, curves of current dimensionless potential versus recovery factor are computed with models of hydrocarbon production systems. Additionally, a method to estimate production profiles using curves of current dimensionless potential versus recovery factor is presented. The author introduces three definitions, (1) the “production potential” is the maximum rate of hydrocarbon delivery for a production system at a given recovery factor. (2) The “maximum production potential” is defined as the maximum rate of hydrocarbon delivery at initial recovery factor. (3) The “current dimensionless potential” is defined as the production potential normalized by the maximum production potential. Several cases and modeling approaches, using coupled models of reservoir, well and gathering network are used. The reservoir was modeled using two approaches: a tank model (material balance equation) and a three-dimensional (3D) simulator. This work studies the effect of changes to the production system on the curve of current dimensionless potential, and how to handle such changes over the lifetime of the field when computing production profiles. It also discusses production scheduling using multiple curves of current dimensionless potential. Expressions and curves of current dimensionless potential versus recovery factor were derived using Arps decline equations and production data of a Norwegian offshore dry gas field. Results show that the curve of current dimensionless potential is not affected significantly by (1) changes in number of wells, (2) initial surface volume in place, (3) layout of gathering system, (4) pipe and tubing diameter, (5) artificial lift and (6) formation permeability. However, the curve is strongly dependent on (1) reservoir drive mechanism, (2) model components considered in the flow-path from reservoir to separator and (3) model upstream and downstream boundary pressures. Curves of current dimensionless potential derived with the Arps exponential decline equation are similar to the results of the dry gas study case.

The size of starch granules in dilute aqueous suspension was measured in-line during gelatinization in a microwave-heated, well-mixed system. The results were compared with those of a previous study conducted with conventional heating. For the starches used (common corn, waxy maize, and cross-linked waxy maize), no significant difference was found between microwave and conventional heating in terms of maximum diameter, temperature of maximum rate of diameter increase, or diameter vs. temperature behavior. These results suggest that there are no differences in the swelling behavior of common and modified maize starches between microwave and conventional heating.

To reveal the microscopic characteristics of the post-explosion coal dust samples, coal dust explosion tests were performed in a 20 L spherical vessel. The explosion characteristic parameters, such as the maximum pressure (Pmax), the maximum rate of pressure rise ((dP/dt)max), ignition time (t) and the deflagration index (KSt) were recorded. Meanwhile, the post-explosion dust samples were collected and analyzed. The research efforts include particle size distribution analysis, SEM analysis and FTIR analysis of dust samples before and after the explosion. The particle size range of post-explosion dust samples became wider according to the mass percent analysis. The microscopic appearance of samples in same particle size range showed some similarity. The porous structure of dust samples was observed by improving the SEM magnification. The chemical structure of dust samples before and after explosion was analyzed by FTIR.

In this study, the explosion characteristics of coal powder in O2 CO2 atmospheres are studied. All experiments are performed in a 20 L spherical vessel. The maximum explosion pressure and the maximum rate of pressure rise are derived from the pressure time evolutions. A three-zone theoretical model has been applied to calculate the flame speed. To overcome the drawbacks of the non-spherical flames generated by pyrotechnical igniters, a continuous ignition spark is used as an alternative ignition source. The experimental results show that maximum explosion pressures are similar when different ignition sources are used. The maximum rate of pressure rise and the flame velocity are very sensitive to the ignition source.