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Alcohol-related liver fibrosis (ALF) is a form of alcohol-related liver disease (ALD) that generally occurs in response to heavy long-term drinking. Ecto-5'-nucleotidase (NT5E), also known as CD73, is a cytomembrane protein linked to the cell membrane

A new forming process for magnesium alloy sheet, namely, electromagnetic impacting medium forming (EIMF), is proposed. Medium is compressed by strong magnetic force which is produced from varied magnetic field between coil and driver sheet. Magnesium alloy sheet can be deformed by a strong force from medium. In EIMF, once impacting or more times impacting is easily implemented, that is difficulty in conventional electromagnetic forming. Effects of different discharge energy and temperature were investigated. Peak forming heights increased linearly with increasing discharge energy and temperature. Distribution of contour and thickness had been revealed. Strains could be improved by increasing temperature and discharge energy. Twice impacting process was carried out. The forming height was enhanced obviously in contrast with results obtained at once impacting. Fracture morphology and optical microstructure were analyzed. It is found that brittle fracture at room temperature and ductile fracture at 200 °C appeared. Due to high strain rate forming process, deformation mechanism (non-basal slip systems) has limit effect. And at 200 °C, twinning is also a main mechanism for AZ31 sheet deformation in EIMF. In further work, EIMF for formability of AZ31 sheet will be improved by affected the deformation mechanism.

This paper proposes an innovative electromagnetic forming process for the manufacturing of aluminum alloy tubes, namely electromagnetic impacting medium forming (EIMF) process using flat spiral coil. The proposed EIMF process was implemented and characterized by numerical and experimental methods. Based on medium height and discharge energy, deformation region of tube was analytically determined and verified by finite element (FE) analysis. Effects of medium height and discharge energy for maximum diameter and strain rate of deformation tube were characterized numerically and experimentally. Flow defect of medium was observed at higher discharge energy. To estimate the effect of capacitance, four types of capacitance were designed and evaluated by numerical analysis. Through EIMF experiments, tubes with temperature from 25 °C to 200 °C were investigated and variations of maximum diameter (expansion ratio), thickness (thinning ratio) were obtained. Comparing with results under discharge energy, temperature has more obvious effects. Major and minor strains displayed higher level at 200 °C. Metallographic and morphologies were characterized by optical microscope (OM) and scanning electron microscopy (SEM). Results showed that refinement of average grain size and ductile fracture depends on the increase of discharge energy and temperature.

We conducted a series of experimental investigations on the mechanical properties of DP600 dual-phase steel under strain rates from 0.001 to 3000 s−1 at room temperature. A split Hopkinson tensile bar was used to capture a high strain rate response. A comparison of the quasi-static and dynamic experiment results showed that the yield strength and ultimate tensile strength increased significantly under dynamic conditions. Fractographs were analyzed by scanning electron microscopy, which indicated a better ductility at a high strain rate. Based on the experimental results, the Johnson–Cook constitutive model was applied to describe the tensile deformation behavior under various strain rates. A reasonable agreement was observed between the experimental data and the Johnson–Cook model. A metallographic analysis of tensile specimens showed that the average ferritic grain size of the fractured specimens at a high strain rate was smaller than that of the fractured specimens under quasi-static conditions. Ferritic grain refinement proved that high-speed forming could enhance the forming ability of the DP600 steel.

In this paper, formability of AZ31 sheet in magnetic pulse forming hybrid actuating with driver sheet and temperature were investigated. The effects of discharge parameters, driver sheet and temperature were investigated on bulging by the experimental analysis. Forming height, thickness of AA1060 driver sheet, forming limit curve (FLC), fracture morphology and microstructure were performed to analyze causes of deformation behaviour for driver sheet and temperature. Analysis of driver sheet and temperature effects reveals that the optimum thickness of the driver sheet and temperature are 1 mm and 200 ℃, respectively. The FLC results show increased by increasing temperature from 25 ℃ to 200 ℃, and then decreased by increasing the temperature such as 250 ℃. Compared with quasi-static forming, the temperature effect for formability is unremarkable in magnetic pulse forming with driver sheet. Demonstrating similar drawability and strechability of AZ31 sheet appeared. Microstructure reveals that high strain rate effect, yield strength decreasing (because of temperature effect) and grain refinement are main reasons to affect the formability of AZ31 sheet in magnetic pulse forming with driver sheet and temperature. However, dynamic recrystallization (DRX) is not observed which is usually accompanied at temperatures higher than 150 ℃ in quasi-static forming.

Magnetic pulse forming is high velocity forming technology, which requires the workpiece with better conductivity. However, high-strength steel with lower conductivity is difficult to deform by magnetic pulse forming. In this paper, AA1060 sheet was employed to drive DP600 sheet which was used to solve the forming problem of high-strength steel in magnetic pulse forming. Experimental tests and numerical method were used to investigate the deformation characteristic of DP600 sheet. Effects of drive sheet and discharge voltage for DP600 sheet deformation were analyzed. Forming height increases with increasing discharge voltage and optimal thickness of driver sheet is 2 mm. Forming profile and thickness of deformed DP600 sheet were provided. Distribution of magnetic field line and magnetic force were presented by numerical simulation. Higher magnetic flux density and magnetic force can be produced by 2 mm Al driver sheet. Deformation process, velocity, strain rate, and principal strain were investigated. During the driving process, DP600 sheet was accelerated and got higher velocity about 252 m/s with 2 mm driver sheet and C = 615 μF/U = 3.38 kV. Principal strain increases with discharge voltage increasing. And the varied trend can be described by quadratic equation.

A novel design and manufacturing method, dubbed “precast,” of the cooling system and tools for a hot forming process was proposed in this paper. The integrated structures of the punch and blank holder were determined by analyzing the bending and reverse-bending deformation of the forming parts. The desired crashworthiness performance of an automotive front bumper constructed with this process was obtained by a tailored phase transformation, which generated martensite-bainite in the middle and full martensite transformation in the corner areas. Varying cooling effects in the formed parts caused the highest temperature to be located in the bottom and the lowest on the end of the formed parts. Moreover, the microstructural distributions demonstrated that the bottom possessed a relatively lower content of martensite, while, conversely, the end possessed a higher content. This was precisely the most desired phase distributions for the hot formed parts. For the six-process cycle stamping, the temperatures reached a stable status after an initial rapid increase in the first three process cycles. The microstructural results verified the feasibility of the hot forming tools under multiprocess cycles.

This paper presents experimental studies of rubber-pad forming process of AA5182 aluminum alloy sheet. The influences of load velocity and rubber pad height for characteristic of polyurethane rubber are investigated firstly by compression tests. It can be concluded that the load force increases quickly with decreasing of rubber pad height. The expansion diameter of polyurethane rubber is insensitive to load velocity at 40 and 60 mm height. Then the deformation characteristic of rubber-pad forming, states of strain, and stress is analyzed to compare with conventional drawing. Furthermore, AA5182 aluminum alloy sheets with thickness of 0.8 and formed target part with diameter of 80 mm and height of 15 mm are investigated under different load velocity varying from 50 to 500 mm/min. The load velocity, load force, and distribution of thickness are analyzed in detail. Results show that the maximum thickness reduction occurs at the bottom corner of the formed part. And the maximum thinning decreases to 20.0% for v = 50 mm/min, 20.0% for v = 100 mm/min, 17.5% for v = 300 mm/min, and 17.5% for v = 500 mm/min. At last, the forming process for target part with diameter of 80 mm and height of 20 mm is also investigated under different load velocity. The results confirmed that it is difficult to form the desired shape.

Thermal effect from warm temperature is always used to improve the formability of AZ31 magnesium alloy sheet. However, it is seldom employed to deform AZ31 sheet in magnetic pulse forming process, due to increasing resistivity and decreasing effect of high strain rate. In this study, Al driver sheets without heating were used to strength effect of high strain rate and drive AZ31 sheet with warm temperature to deform. Method of numerical simulation was used to analyze magnetic pulse forming of AZ31 sheet with driver sheet and temperature. Magnetic flux density and magnetic force with and without Al driver sheet (thickness of 1, 1.5, and 2 mm) and different temperature (25, 100, 150, 200, and 250°C) were investigated. Deformation processes and velocity with Al driver sheet and different temperature were analyzed. The results indicate that it is better for formability of AZ31 sheet to adopt 1-mm Al driver sheet at higher discharge energy and warm temperature.

Hot deformation in 6063 aluminum alloys was investigated by hot compression testing over the temperature range of 573–723 K with strain rates of 0.01–10 s−1 using a Gleeble 3500 thermal-mechanical simulator. Based on the experimental results, constitutive equations compensated with strain were developed to model the hot deformation behavior. The intrinsic workability was further analyzed by establishing three-dimensional processing maps. These maps were constructed based on dynamic materials model to delineate variations in power dissipation efficiency and flow instability domains. Combined with microstructure observation, recommended processing domains are predicated to be within the temperatures range of 673–723 K and strain rates range of 0.01–0.1 s−1. Under such conditions, the main softening mechanism is dynamic recrystallization. The results from these processing maps agree well with microstructure observation.

In this work, electromagnetic impact upsetting (EIU) process was proposed. And EIU and quasi static upsetting (QSU) experiments were performed with Φ6 mm-2A10 aluminum alloy bars. Microstructure evolutions for both processes were revealed by metallographic observations under the varying engineering strains. Results showed that the most deformations for the EIU process significantly concentrated in narrower adiabatic shear bands (ASBs) comparing with the QSU process. The ASBs initialized in the diagonal points of samples and gradually extended to the central with the continuous deformations. And four ASBs encountered and integrated in the central. The high strain rate contributed to deformation concentration and the forming of the adiabatic shear bands. In addition, hardness values for the EIU process were higher than that of the QSU process, demonstrating that the strengthening effect of the strain rate was notable. TEM observations presented that the ASBs with the highest hardness contained many lamellar sub-grains and second phase particles (Al 2 Cu). The high strain rate caused that rotated sub-grains converted into dynamic recrystallization grains within ASBs. Plentiful dislocation tangles and strengthening phases accounted for highest hardness values within the ASBs.

Mechanical behavior and microstructural evolution of AZ31 sheet at high strain rates and elevated temperatures were investigated using a tensile Split-Hopkinson bar. Flow stress and elongation increased with increasing strain rate under high strain rate conditions, but temperature had little effect. Microstructural evolution was analyzed by optical and scanning electron microscopy. Twinning was observed at high strain rates, even at 200°C and 250°C, but not under quasi-static tension. Dynamic recrystallization was observed under quasi-static conditions with increasing temperature, but not at high strain rates. Dimples were observed over the entire temperature range at high strain rates. Increasing ductility was limited compared with that under quasi-static conditions. Dynamic recrystallization occurred at strain rates of 2 000 s−1 and 3 000 s−1 at 250 °C, but the recrystallized grains were very small.

Using a controlled thermal simulator system, hybrid carbon nanotube-aluminum reinforced ZA27 composites were subjected to hot compression testing in the temperature range of 473-523 K with strain rates of 0.01-10 s−1. Based on experimental results, a developed-flow stress model was established using a constitutive equation coupled with strain to describe strain softening arising from dynamic recrystallization. The intrinsic workability was further investigated by constructing three-dimensional (3D) processing maps aided by optical observations of microstructures. The 3D processing maps were constructed based on a dynamic model of materials to delineate variations in the efficiency of power dissipation and flow instability domains. The instability domains exhibited adiabatic shear band and flow localization, which need to be prevented during hot processing. The recommended domain is predicated to be within the temperature range 550-590 K and strain rate range 0.01-0.35 s−1. In this state, the main softening mechanism is dynamic recrystallization. The results from processing maps agree well with the microstructure observations.

At present, with the rapid development of Internet technology, the traditional Internet technology is no longer applicable to the current new Internet technology. At present, Internet technology is gradually found in the direction of Internet of Things technology, and gradually appears in people’s production and life. In this paper, the architecture of the current Internet of Things technology is analyzed and discussed, and its key technologies are gradually analyzed. At the same time, this paper also analyses and discusses the problems existing in the current power communication system, and puts forward the application of the current Internet of Things technology in many aspects, such as automation, emergency communication and so on. At the same time, this paper also hopes to promote the vigorous development of smart grid construction in China through the research and discussion of this topic. In addition, this paper mainly from a professional point of view as a starting point, to explore the functional ...

In this paper, forming behavior of AZ31 sheet in rubber pad forming with warm temperature was investigated by experimental method. Rubber pad is always considered as it is temperature resistant. However, some types of rubbers can endure warm temperature, such as polyurethane for 120 °C and silica gel for 250 °C. Thus, forming for coupling with effects of temperature and flexible of rubber pad is proposed in this paper. The forming process of AZ31 sheet experienced bulging first and then gradually contacting with die, which was different from conventional forming. Fracture presented flat at room temperature and fracture became dentation obviously at 100 °C. When the temperature elevated to 200 °C, the fracture does not occur but the polyurethane was melted. The AZ31 sheet could fill the die successfully with silica gel as rubber pad at 200 °C. The effects of different load velocity for forming of AZ31 sheet were investigated. Thickness increased at bottom of deformed part, due to pressure stress acted from surrounding area. The thickness deceased at the bottom corner. Microstructure of deformed AZ31 sheet was also analyzed. It was indicated that dynamic recrystallization and twinning deformation mechanics were activated which had positive influence for improving formability of AZ31 sheet.

Hybrid carbon nanotube–aluminum reinforced ZA27 composites under hot compressive forces were investigated in the temperature range of 473 – 523 K with strain rates of 0.01 – 10 s−1. From the experimental data, the flow stress curves for increasing strain exhibit typical flow behavior associated with dynamic recrystallization softening. A comparison of predictions from an artificial neural network model and the constitutive equations to describe the hot compressive behavior was performed. Relative errors varied from −4.14 % to 6.75 % for the artificial neural network model and from −15.93 % to 17.29 % using the constitutive equations. The results indicate that the artificial neural network model was more accurate and efficient in predicting hot compressive behavior.

Microstructure and mechanical properties of the welding zone highly depend on the thickness of inner tube for jointing two tubes using magnetic pulse welding (MPW). In this study, the critical thickness of inner 20Fe tube for the Al–Fe welding tubes is investigated by combining the theoretical calculation and experiments. Theoretical analysis demonstrates that plastic deformation zone of the inner tube expands from its inner surface to its outer surface. With equilibrium equations and modified Tresca yield criterion, the critical thicknesses of inner tube under various collision velocities are derived so as to assure the high quality of the welding. The results show that the critical thickness of inner tube increases linearly with the discharge voltage. With the discharge voltage increases by every 2 kV, the critical thickness increases by 0.5 mm accordingly. The theoretical predictions agree well experiments with an error of less than 2.5%. Furthermore, effects of thickness of inner tube on the mechanical properties of welding zone are also investigated.

The plain strain of AZ31 magnesium alloy sheet in magnetic pulse forming was investigated by numerical simulation and experimental method. Combination of uniform pressure coil and Holmberg’s specimen was employed to evaluate the plain strain of AZ31 sheet. The numerical simulation for magnetic pulse plain strain of AZ31 sheet is performed by means of ANSYS FEA software. The magnetic flux density of uniform pressure coil was distributed uniformly, especially at the center of gauged area of AZ31 sheet directly in relation to the deformation behavior of AZ31 sheet. The velocity of typical point increases as increasing energy, and the more position closes to the center of sheet the higher velocity achieves. The forming height is increased with increasing discharge voltage. Compared with C=768 µF and C=1536 µF, the capacitance of 1152 µF is more effective for forming, which is confirmed by experiments. The peak velocity at the center of sheet is about 105 m/s. The major strains of magnetic pulse plane strain lie approximately in the strain ranges of 5.83-6.45%. However, the 3.22-3.82% (major strain) are the limit strains in quasi-static condition. The experimental results indicate that the major strain of AZ31 sheet improves about 75% compared with the quasi-static case.

Hot stamping is an innovative operation in metal-forming processes that almost completely prevents the cracking and wrinkling of high-strength steel (HSS) sheets. The examination of HSS defects using traditional forming limit diagrams (FLDs) is challenging. In this paper, we have used a new FLD, termed 3D FLD, which considers phase transformations (PT), to evaluate the formability of HSS in hot stamping. A numerical model of the hot stamping process was developed to predict the major and minor strain distributions in hot-stamped components. The effect of blank geometry on forming quality and other main process parameters, such as stamping velocity and forming temperature, were investigated. The measured thicknesses of typical points near the crack position agree well with those of the simulated points. These results confirm that the simulation strain was relatively accurate. Cracking and wrinkling can therefore be predicted accurately using the proposed 3D FLD. The blank was found easy to avoid rupture with optimized process parameters and die parameters. Traditional wrinkling criteria can be used to predict the wrinkling of formed parts within engineering error.

Thermal effects in magnetic pulse forming of magnesium alloy sheet were investigated by finite element software ANSYS. The adiabatic temperature produced in magnetic pulse forming was due to the high forming velocity. Distribution of adiabatic temperature is affected by discharge parameters, such as voltage and capacitance. Distribution of adiabatic temperature is predicted by C-P model and J-C model which are always used to describe the forming behaviors of material in high velocity forming. Predicted distribution of adiabatic temperature by C-P model and J-C model increases with increasing of discharge voltage, but decreases clearly with capacitance increasing, particularly at the center position of the deformed part. The highest temperature is 77.7 and 94 °C at C = 1152 μF/U = 2.75 kV (limit forming parameters) predicted by C-P model and by J-C model, respectively. The relationship between velocity and adiabatic temperature is also analyzed. Preliminary study for the effect of adiabatic temperature on the micro-structure of AZ31 sheet in magnetic pulse forming is explored by the analysis for fracture morphology of the deformed sheet.

With the recent research and development trend of the third generation of artificial heart pumps, the scheme of a spiral axial blood pump with magnetic and hydraulic suspension structure was proposed. Using the bearing principle of the fluid dynamic wedge, the effect on radial hydraulic force of the blood pump rotor has been analyzed, which results from the different arc roof length of spiral blade or the different radial clearance of dynamic pressure support. The effects on axial magnetic force of the blood pump rotor has also been analyzed by using the electromagnetic analysis module of ANSYS software, which results from the different parameters of permanent magnetic bearings. The results show that the designed magnetic and hydraulic mixed passive suspension system was simple, compact and high efficient. When the blood pump rotor's rotating speed top to 6000 r/min, the stable suspension of blood pump can been realized; When its rotating speed top to 8000 r/min, the blood pump flow rate can be more than 5 L/min, which can meet the body's physiological needs.

The magnetic pulse forming process of AZ31 magnesium alloy shell using uniform pressure coil at room temperature was investigated. ANSYS FEA software was used to analyze the distribution of magnetic flux density of the uniform pressure coil and magnetic pressure for loading on the AZ31 sheet. The characteristic of forming process of AZ31 shell was revealed, and magnetic pulse forming process of AZ31 shell and effect of Al alloy sheet with different thickness were presented by experiments. Due to impact between sheet and die, the rebound profiles on the bottom of deformed sheets were observed. In order to remove the rebound profile, AA5052 sheets were employed to drive the deformed AZ31 sheets. The section contour of R = 30 mm (R means bottom radius of die) shell deformed by 0.5-mm thickness of driver sheet driving once and R = 15 mm shell deformed by 1-mm thickness of driver sheet driving twice are good agreement with die, not only width direction (AB direction) but also length direction (CD direction). However, there was a big obstacle to deform the AZ31 shell with R = 2 mm, because the die had small bottom radius and sidewall section. Variation of effective strain and velocity with width direction and length direction during magnetic pulse forming without driver sheet and with Al driver sheet were analyzed by simulation.

The implantable axial blood pump, driven by external electromagnet, is studied recently. It oscillats when it is running because of the elastic implanted environment and driving force disequilibrium, etc. In this paper, a model of single erythrocyte in vibrated flow field was built to simulate the deformation and force of the erythrocyte. By using the mechanical injury principle of blood in blood pump, we studied the injury of a single erythrocyte resulted from oscillating boundary flow field. The research results indicated that the shape of the erythrocyte, force and velocity field nearby, which are affected by oscillating boundary flow field, all cause injury to the erythrocyte. All the researches shown in the present paper are expected to provide theoretical foundation for lightening hemolysis by the blood pump.