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There is abnormal wear and fracture of the retainer in the faulty piston pump. To investigate the early failure mechanism of the fractured retainer, a model for the calculation of the transient contact between the overturning retainer and the slipper is presented. The equations of the trajectory between the overturning retainer and the slipper are established based on the transformation matrix and the operating mechanism of the slipper in the oil sucking and discharging areas. The trajectory of the push points between the overturning retainer and the slipper is solved. The failure mechanism of the retainer extrusion wear is determined. The results show that with the increase of the degree of overturning, the degree and range of extrusion and wear between the failure retainer and the slipper is increased. The research elucidates the failure mechanism of the retainer and lays the foundation for the dynamics modeling and coupling vibration analysis of the overturning retainer.

An evidence-theory-based interval perturbation method (ETIPM) and an evidence-theory-based subinterval perturbation method (ETSPM) are presented for the kinematic uncertainty analysis of a dual cranes system (DCS) with epistemic uncertainty. A multiple evidence variable (MEV) model that consists of evidence variables with focal elements (FEs) and basic probability assignments (BPAs) is constructed. Based on the evidence theory, an evidence-based kinematic equilibrium equation with the MEV model is equivalently transformed to several interval equations. In the ETIPM, the bounds of the luffing angular vector (LAV) with respect to every joint FE are calculated by integrating the first-order Taylor series expansion and interval algorithm. The bounds of the expectation and variance of the LAV and corresponding BPAs are calculated by using the evidence-based uncertainty quantification (UQ) method. In the ETSPM, the subinterval perturbation method (SIPM) is introduced to decompose original FE into several small subintervals. By comparing results yielded by the ETIPM and ETSPM with those by the evidence theory-based Monte Carlo method (ETMCM), numerical examples show that the accuracy and computational time of the ETSPM are higher than those of the ETIPM, and the accuracy of the ETIPM and ETSPM can be significantly improved with the increase of the number of FEs and subintervals.

Hydrofoil sections are broadly used in the field of fluid machinery. The leading edge of a hydrofoil structure is closely related to drag and cavitation performance. In this study, we adopt the concept of a bionic design. The fin structure of a fish is simplified and applied to the traditional National Advisory Committee for Aeronautics 0015 hydrofoil. We adopt the Grey–Taguchi method to calculate the best layout. This helps obtain the best drag and cavitation performance. Large eddy simulations are used to verify the scheme. When the ratio of fin depth to length h/L is 0.3, the fin layout length Xn is 7 L, the inclination of fins θ is 7°, and the bionic hydrofoil exhibits the best hydrodynamic performance. Application of the best bionic hydrofoil to the fluid machinery (pump) demonstrates that the hydraulic performance of the pump has been considerably improved.

This paper proposes to alleviate the high-frequency liquid inertial load in piezoelectric pumps by using a type of vibration filter. Theoretical analyses show that the vibration filter can cut off the rigid connection of the liquid inside and outside the pump chamber and smoothen the high-frequency fluctuation components of liquid flow outside the pump chamber. The effect of the vibration filter on improving output flow rate of piezoelectric pump was tested by conducting contrast experiments. It was found that the output flow rate of the piezoelectric pump can be remarkably improved by using the vibration filter, and a maximum flow rate improvement of 10% $\sim$ 50% can be achieved in the non-resonant working frequency of 200 $\sim$ 500 Hz.

People with diseases such as stroke, spinal cord injury, and trauma usually have paretic ankle involvement because of the plantar flexor and dorsiflexor muscle weakness. Individuals with paretic ankle normally have the drop-foot gait, which has the complications of foot-slap after heel contact and toe-drag during the swing phase of a gait cycle. This could cause slow walking speed, short step-length, high metabolic cost, and high risk of tripping. Ankle-foot orthotic intervention is mostly prescribed to treat paretic ankle impairments. In addition, ankle-foot orthoses (AFOs) have been developed to assist human walking, which can reduce the wearer's metabolic cost of walking. To date, three kinds of AFOs have been developed, including the passive AFOs, semi-active AFOs, and active AFOs. This paper provides a systematic review on these three types of AFOs, where the biomechanics of normal and pathological gaits of human, the design concepts of the AFOs, and motion data collection of the human-machine system in human trials are described. The limitations of the currently developed AFOs and future research and development directions of AFOs are discussed, which would provide useful information for researchers to develop suitable AFOs.

Experimental investigations are conducted on an axisymmetric hypersonic inlet to evaluate the effects of trips on oscillatory flows. The model exit is throttled with a fixed block to generate oscillatory flows at a freestream Mach number of 6 in a conventional wind tunnel and a shock tunnel. Schlieren imaging and pressure measurements are adopted to record unsteady flow features. Results indicate that trips with a 1 mm thickness prominently suppress external separations, shorten oscillatory cycles, and modify pressure magnitudes. Trips can reduce the upstream movement ranges of separated shocks from nose regions to locations axially 142 mm downstream. The oscillatory cycles are shortened from 3.75 ms to 3.25 ms and from 4 ms to 3.13 ms in two facilities. Tripped cases generally exhibit higher pressure magnitudes than those of untripped cases, of which the increment is up to 21 times the freestream static pressure for the farthest downstream transducer in the shock tunnel. The effects of trips are related to the streamwise vortexes in wake flows, in which interactions between external separations modify the separated flow patterns and enhance the sustainment of the forebody boundary layers to backpressure. Flow processes causing increments of oscillatory frequencies and pressure magnitudes are analyzed, while the flow mechanisms dominating the processes still need to be clarified in the future. Keywords: Backpressure, Flow separations, Hypersonic inlets, Inlet unstart, Oscillatory flow, Trips

This contribution deals with reductive dehalogenation process used for purification of waste water. A degradation of 2-chlorophenol with different concentrations in solutions with NaHCO3 buffer and iron dust or iron sand particles was studied. Experiments were carried out in closed glass bottles with different solutions or in glass bottles with an aeration system constructed to examine the effect of aeration on the reaction. Oxidation reduction potential and pH were measured regularly after 3h, 6h, 24h, 48h, 72h, 96h, 168h. The samples for HPLC measuring were collected also at the same time. Model solutions of waste water with different concentrations of 2-chlorophenol contained NaHCO3 buffer for stabilization of pH. Two types of iron particles were used for reductive dehalogenation process mainly differ in size distribution of iron particles

The raft-type wave energy converter (WEC), consisting of several hinged rafts and hydraulic power take-off (PTO) systems, captures wave power in a line absorber manner, whose scattered and radiated wave pattern is different from that of a point absorber. This paper focuses on the latching control of a raft-type WEC consisting of two rafts and a hydraulic PTO system. To reduce the complexity of finding the optimal latching duration, the hydraulic PTO system is modelled as a Coulomb damping and the optimal latching control law is derived from a Coulomb damping-based model using the optimal control theory. The effectiveness of latching control on improving power capture ability of the raft-type WEC with a hydraulic PTO system and the benefit introduced by latching control in terms of power improvement are investigated. Results show that the optimal latching control law derived from the Coulomb damping-based model can effectively improve the power capture ability of the raft-type WEC with a hydraulic PTO system. The benefit due to latching control can reach a peak value of 3.04, which is 2 times that introduced by load control. Moreover, latching control can further benefit the raft-type WEC where load control has been performed.

This study proposes the improvement of the output performance of a resonant piezoelectric pump by adding proof masses to the free ends of the prongs of a U-shaped piezoelectric resonator. Simulation analyses show that the out-of-phase resonant frequency of the developed resonator can be tuned more efficiently within a more compact structure to the optimal operating frequency of the check valves by adjusting the thickness of the proof masses, which ensures that both the resonator and the check valves can operate at the best condition in a piezoelectric pump. A separable prototype piezoelectric pump composed of the proposed resonator and two diaphragm pumps was designed and fabricated with outline dimensions of 30 mm × 37 mm × 54 mm. Experimental results demonstrate remarkable improvements in the output performance and working efficiency of the piezoelectric pump. With the working fluid of liquid water and under a sinusoidal driving voltage of 298.5 Vpp, the miniature pump can achieve the maximum flow rate of 2258.9 mL/min with the highest volume efficiency of 77.1% and power consumption of 2.12 W under zero backpressure at 311/312 Hz, and the highest backpressure of 157.3 kPa under zero flow rate at 383 Hz.

To accurately describe the power transmission in the hydraulic power take-off (HPTO) system, a high-precise model for the HPTO system of a raft-type wave energy converter is presented. The model incorporates all the necessary dynamics and the undesirable physical effects, such as pressure drop, flowrate leakage, flow resistance, and friction. The model is validated by the comparison with the results obtained using a hardware-in-the-loop test rig and results show that the proposed model can describe the power transmission more accurately than previous models. Furthermore, the research focuses on the holistic performance of the HPTO system including the transmission efficiencies of HPTO components, the overall transmission efficiency of HPTO system and the power losses of HPTO components across a wide range of wave parameters. Results show that the power losses from each component and the efficiencies of the hydraulic cylinder and the generator increase as wave height increases or raft length-to-wavelength ratio approaches the optimal value, while the efficiencies of the check valves and the pipeline display inverse variation tendencies. Besides, the hydraulic motor is the main contributor to the overall power losses and the HPTO efficiency displays a similar variation tendency against wave parameters with that of the hydraulic motor.

Mechanical properties are critical to the working performance of magnetorheological fluids (MRFs), especially in high temperature situations. This paper presents an experimental investigation to analyze the effects of temperature on mechanical properties of MRFs. First, a parallel disk method was implemented for the shear stress measurement of MRFs and the measurement principle was theoretically illustrated. Then, a detailed introduction to the MRF sample preparation and the testing device development was performed as well. In the study, five kinds of MRF samples with different material parameters were prepared and a shear stress testing device which possesses the temperature control function was developed and evaluated. After these, a series of measurements were conducted on the viscosity–temperature characteristic, shear stress–temperature characteristic and thermal stability of MRF samples. Measuring results indicated that the mechanical properties of MRFs were obviously dependent on temperature. The phenomenon mainly embodied in the reduction of off-field viscosity and shear stress with increasing temperature, as well as the performance degradation after undergoing a low–high–low temperature cycle or a high temperature treatment of more than 150 ℃.

Shock tunnel tests and CFD simulations are conducted to study effects of vortex generators (VGs) on unsteady unstarted flows of an axisymmetric hypersonic inlet with nose blunt radii of 0.8 mm and 3.2 mm. The inlet exit is throttled with a preseted block to generate unstarted flows at a freestream Mach number of 5.9. Unstarted flows of no VGs, 0.5 mm and 1 mm-thick VGs are recorded through schlieren imaging and pressure measurements. Experimental results show that the unstarted flows are characterized with prominent shock oscillations and pressure fluctuations. VGs reduce scales of the external separations, enlarge angles of the separated shock waves, and increase time-averaged magnitudes of surface pressures. The oscillatory period can be shortened from 4 ms to 3.13 ms by 1 mm-thick VGs for the R0.8 mm configuration. The maximum increment of the time-averaged pressure magnitudes can reach 16.2 times the freestream static pressure ( p ∞ ) for the R0.8 mm configuration with 1 mm-thick VGs. In addition, VGs generally increase pressure standard deviations of the measuring points upstream of the throat section within 4.0 p ∞ and decrease those of the downstream measuring points up to 8.6 p ∞ , despite the 0.5 mm-thick VGs condition of the R3.2 mm configuration. Flow mechanisms dominating the effects of VGs on the unsteady unstarted flows are analyzed with the aid of the CFD simulations. Feasibility of VGs on unstarted flow control is also evaluated.

Material properties of the components of magnetorheological (MR) fluids are critical to their control accuracy and service life. The aim of this study was to reveal the effects of temperature on the material properties of MR fluid components. In this paper, a detailed introduction to the components of MR fluids, including main performance indicators and commonly used materials, was presented at first. Then, theoretical analysis and experimental investigation were performed on the temperature-dependent material properties of MR fluid components. These material properties included the magnetization properties of the magnetic particle, as well as the shear viscosity and thermal expansion of the carrier fluid. Experimental results indicated that both the mass magnetization and coercivity of MR particles decreased as the temperature increased and the phenomenon was particularly obvious at high temperatures. Moreover, an increasing temperature could lead to a severe decrease of the shear viscosity and a relatively large thermal expansion of the carrier fluid. Research results from this study may serve to provide a theoretical and an experimental basis for the preparation of MR fluids with high thermal stability.

The Wangfeng–Tianger–Saridala ore district consists of over 20 orebodies with total proven gold reserves exceeding 15 tonnes. The district is located on the EW-striking Tianger (Bingdaban) shear zone in west Tianshan Mountains, northwest China. The lensoid orebodies are distributed along the shear zone in a region about 25 km in length and 1 km in width. Enhanced fluid flow and fracturing controlled location and orientation of mineralized zones during deformation along narrow shear bands oriented oblique to the overall shear zone margins. Fabrics in fractures and strain shadow overgrowths generally plunge steeply, parallel to the lineation in the surrounding cataclasite matrix consisting of new grains of quartz and minor amounts of micas. Native gold occurs in mylonitized granites or mylonitized sulfide–mica–quartz veins. Gold grade is closely related with the occurrence of sulfide–quartz veins. Pyrite and pyrrhotite in gold-bearing sulfide–quartz veins contain inclusions of native gold. Chondrite-normalized rare earth element (REE) distribution patterns for pyrite from the orebodies show light REE enrichments and negative Eu anomalies. Relationships between gold contents and Th/U, Zr/Hf and (La/Yb) N values for pyrites imply that gold-rich pyrites are different from gold-poor pyrites, thus indicate that the pyrites in the orebodies have a different origin compared with those in wall rocks. A Rb–Sr isochron for the mylonitized Au-bearing quartz veins indicates an age of 224 ± 14 Ma with an initial 87 Sr/ 86 Sr ratio of 0.7294 ± 0.0089 (MSWD = 1.1). This age is conformed by 40 Ar/ 39 Ar dating on muscovites (220.9 to 222.5 Ma), which is interpreted as the age of ore-formation in the Tianger deposit. High initial 87 Sr/ 86 Sr ratios (0.7294), high δ 34 S values (+ 11.2 to + 16.5‰), low δ 18 O H2O values (1.67 to 3.07‰) and low δ D values (− 84 to − 104‰) indicate that the ore-forming fluid was unrelated to any magmatic process.

Kerogen was treated for 24 h at temperatures of 250–700 °C and pressures of 500–1500 bar. Raman spectroscopic study of the run products documented systematic changes in both the first- and second-order spectral features with temperature and pressure. The micro-FTIR analysis of the kerogen treated showed that the presence of hydrogenated functional groups and importance of aromatic rings in the structures of the kerogen increased with temperature. An abrupt change in the chemical composition and structural state of the kerogen treated occurred at ∼500 °C.

Dynamic characteristics of the priority control system are of great influence to the control effect, response speed, and working stability of the high-speed on–off digital valve. The main focus of this study is on revealing the dynamic properties of the priority control system for a developed high-speed on–off digital valve. In this article, a detailed introduction to the high-speed on–off digital valve and its priority control system is performed first, which includes the system function, structural composition, and operation principle. Thereafter, a simulation model of the priority control system is established using the AMESim software and the dynamic characteristics are simulated. Simulation results including the variations in the pulse-width modulation signal, coil current, and the main spool displacement of the directional valve are presented and discussed. They indicate that the opening time of the main spool increases with the duty ratio of the voltage signal. Moreover, the main spool displacement is basically equal in one single pulse-width modulation signal cycle, and thus, it is proportional to the cycle number of the pulse-width modulation signal. As a consequence, the priority control system possesses a good dynamic characteristic for the high-speed on–off digital valve as a pilot valve to achieve proportional control of main spool displacement for the directional valve.

Water of high pressure and temperature is attracting attention for its unique properties and here an in situ observational technique has been developed to study organic matter transformations in H-P and -T (high-pressure and -temperature) water. Three samples of different kind involving aromatic organic compound, polymer, and natural biomass behave greatly different. Anthracene dissolves in water at the temperature of 325 °C and corresponding pressure of 315.9 MPa and remains stable till the highest temperature of 420 °C of this work. Polystyrene and rice straw hydrolyze in the form of heterogeneous phases in H-P and -T water. Polystyrene melts to form non-soluble liquid spherule before hydrolysis, whereas rice straw hydrolyzes directly from non-soluble solid. The light organic molecules produced from hydrolysis dissolve in water at high temperatures and separate out during cooling. The study is helpful to understand reaction mechanism and process of hydrolysis of biomass and polymer in H-P and -T water.

The chemical composition of a barren biotite granite, a two-mica granite, and a rare metal-bearing pegmatite (the No. 3 vein in Keketuohai, Altay Mountains, northwest China), along with mineral separates of apatite and mica, were analyzed and compared in the present work. Bulk chemistries of biotite granite, two-mica granite, and pegmatite rim are consistent with fractional crystallization trend from granites toward pegmatite. Changes in pegmatite composition can be explained mainly by fractional crystallization of biotite. Rb–Sr isochrons yield 248.8±7.5 Ma for the biotite granite, 247.8±6.3 Ma for the two-mica granite, and 218.4±5.8 Ma for the pegmatite rim. Similar geochemical characteristics, including initial e Nd(T) values (ranging from −0.76 to −3.04) for apatites, similar initial e Nd(T) values for whole-rock samples of studied granites and pegmatite (ranged from −1.40 to −3.21) and for biotites from granites (ranged from −2.75 to −3.15) suggest that these rocks were derived from a common magma source. Old continental crust may have played a significant role in magma generation. Based on these data, we interpret the evolution of the Keketuohai granite–pegmatite by magma differentiation from a common source. Biotite granite was the first to crystallize, followed by two-mica granites. The residual melt was probably stored in a granitic batholith. The pegmatite veins were injected ∼30 M.y. later during another episodic tectono-magmatic event in the Altay Mountains.

The objective of this study is to demonstrate the basic characteristics of thermophilic strain TH-2 and evaluate the effect of strain TH-2 on different crude oils. Strain TH-2 is a non-motile, Gram-negative, oil-degrading thermophile that was isolated from a reservoir of the Shengli oil field in East China. The cells of strain TH-2 were grown at high temperatures up to 85 °C in the neutral to alkaline pH range. Depending on the culture conditions, the organisms occurred as single rods, or as filamentous aggregates. Strain TH-2 was grown chemoorganotrophically and produced volatile fatty acids and such surfactants as 1,2-benzenedicarboxylic acid-bis ester, dibutyl phthalate, and di-n-octyl phthalate. It could use different organic substrates (acetate, d -glucose, fructose, glycerol, maltose, pyruvate, starch, sucrose, and xylose). Laboratory studies have demonstrated that the strain affected different crude oils, converted and degraded various components and changed the physical and chemical properties of crude oils. The strain TH-2 degraded crude oil and growth of the bacterium on crude oil resulted in loss of aromatic hydrocarbons, resins, and asphaltenes. The bioconversion of crude oils leads to an enrichment in lighter hydrocarbons and an overall redistribution of these hydrocarbons. The interactions of microorganisms with crude oils are variable and depend on the microbial species and the chemical compositions of crude oils. Different interactions may influence the efficiency of processes in which single or mixed microbial species are used for the oil treatment and may also suggest possible combinations of biological and chemical technologies.

Mixtures of CO 2 -NaCl-H 2 O contained in synthetic fluid inclusions are studied by laser Raman spectroscopy at high temperatures. With increasing temperature, the band splitting (X) of υ 1 -2υ 2 diad of spectrum of CO 2 presents more variations, and the intensity ratios of the hot bands to the υ 1 -2υ 2 diad increase. For mixtures of gas phase rich in CO 2 and liquid phase rich in H 2 O before homogenization, the strength of hydrogen bonding of water in the liquid phase decreases almost linearly with increasing temperature. When mixtures become homogeneous liquid phases, carbon dioxide content increases significantly as a result of the abrupt decrease in hydrogen bonds. Our results show that the hydrogen bonds change only slightly at higher temperatures above the homogeneous point, and a certain extent of the hydrogen bonds still remains at the highest temperature of 550°C of this work. The study is helpful to Raman spectroscopic analysis of natural fluid inclusions at high temperatures.

A simple and inexpensive cubic zirconia anvil cell has been developed for the performance of in situ Raman spectroscopy up to the conditions of 500 degrees C and 30 kbar pressure. The design and construction of this cell are fully described, as well as its applications for Raman spectroscopy. Molybdenum heater wires wrapped around ceramic tubes encircling two cubic zirconia anvils are used to heat samples, and the temperatures are measured and controlled by a Pt-PtRh thermocouple adhered near the sample chamber and an intelligent digital control apparatus. With this cell, Raman spectroscopic measurements have been satisfactorily performed on water at 6000 bar pressure to 455 degrees C and on ice of room temperature to 24 kbar, in which the determinations of pressures make use of changes of the A1 Raman modes of quartz and the shift of the sharpline (R-line) luminescence of ruby, respectively.

The Xihuashan, Dangping and Piaotang deposits in the Jiangxi Province, south China can be considered as typical high-temperature hydrothermal quartz vein-type W-Sn mineralization, that is temporally and spatially related to Mesozoic S-type granite. Microthermometric studies of fluid inclusions in various minerals from these deposits were conducted to obtain homogenization temperature and salinity data. Major organic and inorganic aqueous components of the fluid inclusions were extracted by a crush-leaching, and concentrations of short-chain carboxylate (formate, acetate, propionate, oxalate), fluoride, chloride and sulfate anions in the leachates were determined using ion chromatography. The results indicate the presence of formate and acetate as well as minor amounts of oxalate and propionate in leachates, and the dominance of formate over other carboxylates. The molar ratio of acetate to formate appears to be a potential indicator of the redox state for the ore fluid system. Oxygen and hydrogen isotopic data show that inclusion water in quartz is mainly magmatic in origin. It is postulated that the dissolved carboxylate anions in the ore fluids for the deposits probably were generated by the breakdown of kerogen in “primitive sedimentary rocks” during the formation of S-type granites. The possibility of inorganic synthesis of the carboxylate species in a C-H-O system can not be excluded.

The unpredictable power fluctuation due to severe heating has demonstrated to be a critical technique bottleneck restricting the application of magnetorheological (MR) clutches in vehicle industry. The aim of this study is to introduce a low-cost transient simulation approach for evaluating the heat build-up and dissipation of a liquid-cooled MR vehicle clutch. This paper firstly performs a detailed description of the developed MR clutch in terms of operation principle, material selection and configuration. Subsequently, transient temperature simulations are carried out under various conditions to reveal the distribution, variation and impact factors of the transient temperature field. Following these, an experimental setup is established for heating tests of the clutch prototype. Experimental results concerning the temperature variation of MRFs and the maximum allowable transient slip power (MATSP) of the clutch prototype are presented, which in return verify the correctness and feasibility of the simulation.

In order to verify the presence of residual organic matter in some S-type granites, a method used conventionally in petroleum geochemistry for isolation of kerogen was employed to separate carbonaceous material (CM) from the Xihuashan granite, Jiangxi Prov., China. Optical, XRD and SEM/EDAX analyses identified the acid-insoluble residue as mainly composed of various mineral debris, with a minor carbonaceous fraction found in the residue. LMR and micro-FTIR studies showed that the residue contained a small amount of CM, which is heterogeneous in composition and structural state. The occurrence of CM in the granite implies that this granitic magma originated from sediments and crystallized at relatively lower temperatures and high pressures. This deduction is consistent with geological and geochemical studies of the Xihuashan granite. A tentative model was suggested which connects CM in S-type granite with organic matter in sedimentary rocks. The conditions under which CM can be preserved in S-type granite are discussed. The occurrence of some heavy hydrocarbons is expected in the Xihuashan granite.

The carboxylate (formate, acetate, propionate and oxalate) and common inorganic anions (F − , Cl − and SO 2− 4 ) compositions for aqueous fluid inclusion leachates from 17 mineral samples collected from various deposits have been determined using ion chromatography in conjunction with microthermometric measurements on the fluid inclusions of their host minerals. The minerals, quartz, fluorite, barite, beryl and a few `ore' minerals (wolframite, pyrite and galena), came from hydrothermal vein-type deposits in felsic igneous rocks or Archean metamorphic rocks. The results indicate that short-chain carboxylates are common components in hydrothermal fluids and can be present in considerable amounts. Formic acid (as formate) is the dominant species over other carboxylic acids. The present study raises new questions about the origin and geochemical significance of carboxylates in hydrothermal ore-forming processes.

The solubility of gold and quartz in 0.01, 0.10 and 1. 00 mol/kg NaCl solutions with various pH was determined in the presence of the NNO oxygen buffer at 300°C and 50 MPa using a flexible gold cell hydrothermal apparatus. The Au speciation in the SiO2-NaCI-H2O system was inferred and the equilibrium constants for the following dissolution reactions were obtained: Au+H2O = AuOH0+1/2H2, logK(AuOH0) = -7.92 ± 0.25; Au+Cl-+H2O = AuOHCl-+1/2H2, logK(AuOHCl-) = - 7. 56 ± 0.65. The present study suggests that Au as AUOH0 and AuOHCl- is basically transported in ore-forming solutions under geologically realistic conditions of acidity, chloride molality and oxygen fugacity. The reason for the common association of Au with SiO2 in hydrothermal gold deposits is discussed.

Geological studies demonstrate that liquid immiscibility in felsic magma closely associates with the ore forming process. In order to obtain experimental evidence demonstrating the relationship between the ore forming process and liquid immiscibility in felsic magma, we carried out a series of experiments at high temperature and atmospheric pressure. The experimental results show that the granite ∼ KBF 4 ∼Na 2 MoO 4 system is a homogeneous melt at high temperature. With decrease in temperature, however, the melt decomposes into two immiscible melts: silicate melt and ore-forming melt. The ore-forming melt exists as globules in the silicate phase. Molybdenm, Ca, Na, Mg, P, Mn, F, B, and OH are concentrated in these globules. The ore forming melt is characterized with very low SiO 2 and Al 2 O 3 concentrations but the concentration of MoO 3 and CaO is very high. In contrast, the silicate melts are significantly enriched in SiO 2 and Al 2 O 3 , and depleted in MoO 3 and CaO. In the silicate melt the concentrations of network modifying elements (e.g. Mo, Ca, Na, P, Mg) and volatiles (F, OH) are very low. The differences between the two immiscible melts exist not only in chemical composition but also in structure. The ore-forming melt structurally consists of [MoO 4 ], [MoOF 4 ], [B(OH) 4 ], and OH, while the silicate melt is [Si0 4 ]. Because of the difference in composition and structure the two immiscible melts possess different physical properties. Compared to silicate melt, the ore-forming melt has a lower density and viscosity, which permits the globules to behave as bubbles in granite magma and to move and concentrate in the upper part of magma chamber. This process is probably responsible for the concentration of ore-forming elements in the upper part of granite bodies and their immediate aureoles. The present experimental results suggest that liquation in felsic magma can be the first step in the ore-forming process during granitoid evolution.

Thermal characteristics have a critical influence on the working stability, control accuracy, and even service life of a magnetorheological (MR) fluid-based clutch. The present study aims to reveal the thermal characteristics of a proposed liquid-cooled MR clutch under various operating conditions. In this paper, theoretical analyses of heating and heat dissipation of the MR clutch was performed firstly. Then a steady temperature simulation was carried out on the MR clutch, followed by a detailed illustration of the experiments, including MR fluid selection, experimental content and procedure. Thereafter, several heating tests were conducted on the MR clutch, and experimental results concerning the slip power loss of the clutch, temperature variation of the MR fluid, temperature effect on the torque output, and maximum allowable slip power of the clutch were presented and discussed. Experimental results indicate that the proposed liquid cooling method can effectively assist in the heat dissipation of the clutch. Moreover, the temperature increase can lead to a reduction of both the viscous torque and total output torque, especially after long-term service. Furthermore, the allowable steady slip power of the clutch is 35 kW and the allowable transient slip power reaches up to 53.2 kW for a slip time of 120 s under the present experimental conditions.

Na-F solutions with different pH were allowed to react under flow conditions with limestone, dolomite and siderite at 300 and 400°C at 500 bars, in order to understand the geochemical characteristics of the interaction between rock and F-bearing hydrothermal solutions. The mineralogical and chemical composition of these carbonate rocks was studied by chemical analysis, XRD and SEM/EDAX before and after reaction with Na-F solutions. Based on an approximate thermodynamic calculation the formation of alteration phases is discussed. The pH value at room conditions and the contents of K, Na, Ca, Mg, Fe, F, SiO2 and total dissolved CO2 in solution after interaction with carbonate rocks were determined. From solution chemistry data, it is found that the amount of Na and F in the reacted solutions seemed to have roughly similar fluctuations with time, and hence, carbonate might be an effective precipitating agent for Fe in hydrothermal solutions. The present experimental study demonstrates that hydrothermal metasomatism played a very important role in the formation of the Baiyun Ebo iron deposit.

The paper mainly deals with the design of hardware for an automatic fire fighting system, which aimed at closed combustible places. This system adopts single chip microcomputer with smoke sensor and temperature sensor as the detective devices. By using the single chip microcomputer, it can achieve the aim of automatic fire fighting. And, this system uses high pressured nitrogen as the fire extinguishing agent, which is economical and environment friendly. It accords with the human’s needs of environmental protection.