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The purpose of this study is to investigate the influence of dimple radius, depth and density on the lubrication performance of the plunger.

A lubrication model was adopted to consider eccentricity and deformation during the working process of the plunger, and a rig test was performed to confirm the simulation results. The texture was fabricated using laser surface texturing.

The simulation results suggested that when dimple radius or depth increases, oil film thickness of the plunger increases before decreasing, and asperity friction displays an opposite trend. Therefore, appropriate microdimple texture could facilitate lubrication performance improvement and reduce the wear. Microdimples were then lased on the plunger surface, and a basic tribological test was conducted to validate the simulation results. The experimental results suggested that the average friction coefficient decreased from 0.18 to 0.13, a reduction of 27.8%.

The introduction of microdimple on a plunger couple to reduce friction and improve lubrication is expected to provide a new approach to developing high-performance plunger couple and improve the performance of the internal combustion engine. If applied, the surface texture could help reduce friction by around 27% and cap the cost relative to the plugger friction.

The microdimple texture was introduced into the plunger couple of a vehicle to reduce the friction and improve the performance. Findings suggested that surface texture could be used in the automotive industry to improve oil efficiency and lubrication performance.

The peer review history for this article is available at: http://dx.doi.org/10.1108/ILT-07-2020-0259.

High-pressure die casting is one of the manufacturing techniques used for the rational mass production of metal parts. Due to the high velocity of the molten metal during the injection phase, the die casting of aluminum is so complex and it is almost impossible to calculate these exact performances. Numerical simulation is an effective way to optimize the injection phase and minimize air entrapment that causes porosity defects in the metal. Generally, the filling phase of the molten metal in the shot sleeve is neglected in most scientific work. This phase is followed by a rest period to allow the escape of the resident air bubbles (gravity effect). The paper aims to discuss these issue.

It is relatively clear that the model described poses a great challenge for numerical implementation, especially for 3D geometries. The governing transport equations are solved numerically using the commercial CFD solver Fluent and the equations are discretized using a pressure-based finite volume method. The coupling pressure–velocity was solved by the PISO algorithm. The PISO algorithm takes relatively more CPU time per solver iteration, but it significantly decreases the number of iterations required for the convergence of the transient flow problems. Laminar flow inside air and molten metal was assumed. In order to describe the behavior of the molten metal, a VOF model has been activated. The model makes it possible to account for the moving boundary due to the variation of the shot sleeve volume caused by the plunger displacement. The scheme used in the discretization of momentum equation was the first-order upwind scheme, and the scheme used for the pressure was the PRESTO. The profile of the plunger velocity, boundary conditions change with time and the physical properties change with liquid fraction were used by implementation of a user-defined function. For the discretization of the domain, an unstructured mesh with triangular elements is used. After conducting mesh sensitivity study, a mesh having 53,813 triangular elements has been chosen for the present study. The convergence criterion was set equal to 10–4 for all parameters.

The results show that the rest and global filling times increase by 2.5 and 8.57 percent with decreasing the pouring velocity by 10 percent. In addition, the rest and global filling times decrease by 5.77 and 8.12 percent with increasing the pouring velocity by 10 percent.

After the filling phase, it is necessary to offer a rest period before the injection phase. However, the rest and global filling times increase by 2.5 and 8.57 percent with decreasing the pouring velocity by 10 percent. In addition, the rest and global filling times decrease by 5.77 and 8.12 percent with increasing the pouring velocity by 10 percent. Increasing the pouring velocity by 10 percent leads increasing of the molten metal velocity in the shot sleeve and requires a delay of time of the beginning of the faster plunger movement by 7–10.5 percent. On the other hand, Figure 12 shows that increasing the pouring velocity requires increasing of the plunger velocity during the injection phase, thus increasing the pouring velocity. In order to overcome this problem, it is necessary to reduce the injection velocity and prolong the period of the slower plunger movement.

In combination with an aeroplane having a wing with an aileron hinged to the rear portion thereof to swing up or down from a neutral position to either an ordinary or extreme deflected position and back again, a control for the aileron comprising an actuating element in the pilot's compartment of the aeroplane, a sleeve connected pivotally to the front portion of the aileron and adapted in response to axial shift thereof to swing said aileron, a plunger having one end thereof fitting within the sleeve and its other end mounted in the wing so that said plunger is rotatable without axial displacement, means between the actuating element and said other end of the plunger for effecting rotation of the plunger in response to control movement of said element, and a roller and cam slot motion imparting connection between the plunger and sleeve operative in response to rotation of said plunger to shift the sleeve axially and thus effect swinging of the aileron, the slot of said connection being of helical design and formed in the sleeve and having the intermediate part thereof adapted to receive the roller when the aileron is in or near its neutral position and arranged so that when the roller is disposed therein the aileron is locked against swinging movement except by rotation of the plunger, and also having one end part thereof adapted to receive the roller when said plunger is rotated in one direction in order to swing upwards the aileron into its ordinary or extreme deflected position and curved and of such pitch that when the roller is therein the aileron is free so that it tends in response to flow of air there‐against during flight of the aeroplane to return downwards to its neutral position, and its other end adapted to receive the roller when the plunger is rotated in the reverse direction in order to swing the aileron downwards into an ordinary or extreme deflected position and curved and of such pitch that when the roller is therein the aileron is free so that it tends in response to flow of air there‐against during flight of the aeroplane to return upwards to its neutral position.

Two friction models of Fe-Fe and Diamond-like carbon (DLC)-Fe were established by molecular dynamics (MD) method to simulate the friction behavior of traditional fracturing pump plunger and new DLC plunger from atomic scale. This paper aims to investigate the effects of temperature and load on the friction behavior between sealed nitrile butadiene rubber (NBR) and DLC films.

In this study, MD method is used to investigate the friction behavior and mechanism of DLC film on plungers and sealing NBR based on Fe-Fe system and DLC-Fe system.

The results show that the friction coefficient of DLC-Fe system exhibits a downward trend with increasing load and temperature. And even achieve a superlubricity state of 0.005 when the load is 1 GPa. Further research revealed that the low interaction energy between DLC and NBR promoted the proportion of atoms with larger shear strain in NBR matrix and the lower Fe layer in DLC-Fe system to be much lower than that in Fe-Fe system. In addition, the application of DLC film can effectively inhibit the temperature rise of friction interface, but will occur relatively large peak velocity.

In this paper, two MD models were established to simulate the friction behavior between fracturing pump plunger and sealing rubber. Through the analysis of mean square displacement, atomic temperature, velocity and Interaction energy, it can be seen that the application of DLC film has a positive effect on reducing the friction of NBR.

The purpose of this paper is to provide a study of inertial propulsion.

In this paper, the theory of inertial propulsion under dry friction and under viscous friction is developed.

As inertia propelled devices do not have any external moving parts; the propelling mechanism is completely enclosed inside the device. For inertial propulsion under dry friction, the equations of movement are explicitly derived and provided in closed form, so that such a device can be designed with its parameters computed exactly. For inertial propulsion under viscous friction, on the other hand, there is no closed form for the equations of movement, its dynamics are provided so that a device can be designed using a computer algebra system, as illustrated in the paper.

The paper demonstrates that an inertia propelled device under dry friction moves in the opposite direction than the same device under viscous friction.

THE following description of the fuel supply systems of the BMW 132K and 132N, “Bramo” Fafnir 323 P‐1 and BMW 801 air‐cooled radial engines is based on the following reports supplied by the Ministry of Aircraft Production.

In a constant speed, variable pitch propeller an over‐ride device is automatically brought into operation to move the blades to the feathering position when the power unit stops, and means are provided by which the over‐ride is automatically put out of action when an attempt is made to start the power unit by ‘wind‐milling’, and by which the over‐ride is automatically restored when the speed rises to that at which the unit should be self‐operating. When the power unit stops a governor 23 allows a spring 22 to force a valve 19 to the left, thereby allowing motive fluid from a pipe 12 to flow into the left‐hand end of a cylinder 16 to operate a plunger 15 which moves the propeller blades 13 to the minimum pitch position. The resultant change of torque acting on a torque meter 39 closes a switch 37 to complete an electrical circuit for actuating a solenoid 35 controlling a valve 34 which allows motive fluid to be applied from pipe 31 to the spring‐loaded plunger 28 of the over‐ride device. The plunger moves the valve 19 to the right, allowing fluid into the right‐hand end of cylinder 16, thereby moving the blades to the feathering poistion. The circuit may also be completed by the pilot closing the fuel isolator valve 36. To start the power unti by wind‐milling, ignition switch 46 of the power unit is closed, the govenor controlled switch 47 being already closed. A solenoid 45 then opens a switch 44 and breaks the circuit to the solenoid 35 so that the valve 34 closes to cut‐off the supply of fluid to the over‐ride plunger. The spring 22 is thus able to move the valve 19 to the left with the result that the blades are moved from the feathered position to cause ‘wind‐milling’. If at a predetermined speed the unit does not then become self‐operating, its governor will open the switch 47 causing switch 44 to close to complete the circuit to the solenoid 35. The valve 34 will be raised to bring the over‐ride into operation, causing plunger 28 to move valve 19 so that the propeller blades are moved to the feathered position.

The seeker value is a crucial part of a navigation system, able to adjust the nitrogen airflow of the system so as to manipulate guiding and tailing movement. The paper aims to determine the causes of failure of the valve system.

In order to reduce friction and ensure the smooth operation of the valve, a new MoS₂ solid film lubricant cured at room temperature, was coated on the plunger surface of the valve. SEM, EDS, and FTIR analysis was conducted.

Through analysis it was found that the lock failure of the valves was caused by the absence of MoS₂ in the surface and softening and melding of the film at an extended electrifying.

The paper outlines the strategies to avoid lock failure – by improving the quality of the solid film lubricant and modifying the assembly process of the valve.

A clamp comprising in combination a guide having parallel upper and lower members and inter‐connecting side member forming a closed guide frame, said lower member carrying a plane clamping surface, a plunger passing through the said lower member of said frame, a second plane clamping surface carried on one end of said plunger and positioned adjacent said first mentioned clamping surface carried by said frame, a spring in said guide frame surrounding said plunger and extending between said lower member and an abutment carried by said plunger adapted normally by applying force between said lower member and said abutment to force said clamping surfaces together and means carried by said plunger and movably associated with said frame to compress said spring and force said clamping surfaces apart whereby they may be placed over objects to be clamped.

The purpose of this paper is to present a new device (thermoelastic actuator) for accurate control of position whose principle is based on thermal dilatation of its working unit brought about by induction heating.

The device must satisfy the prescribed operation parameters (mainly the above thermal dilatation). The task to find them is a multiply coupled problem (interaction of electromagnetic field, temperature field and field of thermoelastic displacements) that is solved by the finite element method supplemented with a number of other procedures.

The control of position based on the described thermoelastic effect is very accurate and ranges from 1×10⁻⁶ to 1×10⁻³ m.

The device also contains two self‐locking friction clutches of conical shapes whose purpose is to fix the position of the plunger in the prescribed position. Further attention should be paid to their dynamic behaviour during the process of fixing.

The device can be used in various technical domains such as optics and laser or microscope techniques.

The principal part of the device contains no movable element, which is a substantial advantage in comparison to other systems based on mechanical, hydraulic or pneumatic principles working with movable elements or media.