Recent Patents on Mechanical Engineering - Volume 6, Issue 3, 2013

A review of recent patents and academic articles on micro flat heat pipes over the past decade is presented herein. Firstly, the development history of the mathematical models of the micro flat heat pipes is chronologically summarized. Then, some major investigations in the micro flat heat pipes, both experimental and theoretical, are summed up. Besides, some innovative ideas and novel micro flat heat pipe designs for particular applications are also documented along with comparisons and discussion on various cross-sectional shapes and designs of wick structure, such as grooves, sintered powders, nanotubes and their combinations. Finally, the challenges in the research of micro flat heat pipes are discussed briefly and the development tendency is prospected according to the existing achievements.

Micro Electro-Mechanical System (MEMS) mainly includes two parts, sensor and resonator. Micro resonators are widely applied in the radio frequency (RF) field for its high isolation and low loss. The principles of micro resonators are introduced firstly, including comb resonator, beam resonator, disk resonator, film bulk acoustic resonator (FBAR), cavity structure resonator, and surface acoustic wave resonator (SAW). The applications of micro resonators secondly are discussed, such as in the filter, duplex, sensor, mixer, and oscillator. The filter character of micro resonators is analyzed. The frequency range and Q value of micro resonators are discussed too. Function of frequency conversion, micro resonator work in different frequency bands, will be a new development direction of micro resonator, besides high frequency, high Q, and wide bandwidth. In this article, various patents have been discussed.

This work (a continuation of the author's prior research on small arms recoil reduction) presents a rifle operating group design for small arms recoil reduction. This recently-patented invention is an application of a previouslypatented 7.62mm concept demonstrator to reduce the recoil force transmitted to the user during operation. The recoilmitigating technology developed for the original 7.62mm concept demonstrator has been packaged into a compact and practical rifle operating group design. Like its predecessor, the rifle operating group (the rifle internal components that are responsible for ammunition feeding, firing extracting and ejecting) includes design features to reduce the propellant gas contribution to recoil force and cancel the moving internal component contribution to recoil force. The specific design features in the original invention and follow-on invention for recoil reduction are a translating barrel, a spring-supported upper receiver and a counter-mass that is driven by rack and pinion gears. In computer-based firing simulations, the rifle operating (like its predecessor) produced recoil reaction forces that were substantially less than those produced by the M240 machine gun.

Sound radiation from vibrating panels plays a crucial role in the study of interior noise in transportation vehicles. In recent years, several patents have been issued for inventions in the field of sound reduction technologies to mitigate aircraft noise. This work presents a theoretical analysis and simulations to investigate sound transmission through plate-like multi wall structures. An analytical model is developed to predict sound transmission through infinite-sized triple panel partitions placed in a rigid baffle, from a viewpoint of practical noise control. A numerical procedure is also developed to evaluate the transmission characteristics of finite partitions due to an incident diffuse field. The method is based on a hybrid FEM/Rayleigh methodology and utilizes numerically calculated sound transmission loss of flat multi panel partitions and box like cavities with idealized boundary conditions. Two simplifying assumptions are made: the surrounding medium is air and the radiated sound power is calculated by an array of discrete elemental radiators. Several examples are presented to demonstrate the accuracy of the proposed approach. A theoretical performance analysis is finally carried out on a triple panel partition representative of a more complex triple wall aircraft-type window. The testbed design, used for this study, is guided by an effort to quantify sound insulation capabilities of aircraft windows with a specific focus on passenger's protection against noise transmitted through fuselage panels.

In recent years, a large number of patents have been devoted to developing the rapid molding technology of metal arc spraying with high melting point and high hardness metal. It is extremely attractive to manufacture arc spraying die not only because the material is relatively cheap but also the die shell with high hardness and strength could greatly improve the service life of spraying die thus to expand the application scope of spraying die to provide better precision for forming manufacture industry. Among them, one patent is about a high-melting metal mold shell non-internal stress rapid manufacturing process and device wherein the high-melting metal wire material is used as a self-fluxing electrode and an arc with an extremely high temperature generated by gas discharge is used as a heat source, atomizing the high-melting metal material in a molten state by high-speed gas flow of compressed gas, spraying and depositing the molten spraying particles on the alloyed master mold surface. In the paper, the theoretical analysis and experimental research for rapid manufacture technology of arc spraying 3Cr13 automobile's front hood die have been done. SOMOS 14120 resin master pattern is made with stereo lithography apparatus (SLA). The allumen basement for master pattern is made with Sulzer Metco arc spraying device. QD8-LA arc spraying system is used to spray 3Cr13 martensite stainless steel with the diameter of φ2. The fusion metal material is pulverized with 0.5MPa high pressure air flow; sprayed and deposited on the surface of master pattern to form compact metal shell in 3-6mm thickness, which is the die shell. The die shell accurately copies geometry of resin master pattern and gets the necessary die cavity. The rapid manufacture of automobile's front hood die is completed after the post-processing technology is finished of die shell, including reinforcement, demould and polishing, etc. In addition, the rapid die's mechanical property is evaluated and the result has been proved that, the bond strength between coating and matrix is more than 28.2MPa, the surface hardness is more than HRC48; the shape error for free-form surface is < 5% (1m) and the surface roughness Ra is less than 3.2μm

In recent years, a number of patents have been devoted to designing micro robots for minimally invasive therapies inspired by Paramecium. Paramecium changes its swimming direction due to application of an external magnetic or electric field. Changing ciliary beat direction and frequency have been identified as possible methods for maneuvering through water; however, effects of variations in ciliary spacing on swimming trajectory have been poorly studied. In this work, it is aimed to analyze the effects of adjusting the ciliary spacing on swimming trajectory. For determining the swimming trajectory, Paramecium membrane is discretized to boundary elements with length of 15μm on which there are 5 cilia beating in an effective and a recovery stroke. It is observed that increasing the ciliary spacing on the upper boundary by 5% for 0.35 seconds leads to a mean 10 degrees of Paramecium rotation. This proves that even a slight error in measuring this parameter leads to great errors in determining the swimming trajectory. Also, due to lower energy consumption, variations in ciliary spacing could be an optimum means for micro robotic maneuvering.

In this paper, transient heat transfer through rectangular porous fin is numerically investigated. The effects of thermo-geometric fin parameter and convection heat transfer in porous media are considered. In this work, Darcy's model is adopted to derive the energy equation governing the heat transfer process through the porous fin. The Darcy's model simulates the solid-fluid interactions inside the porous fin due to the flow infiltration through it. The governing equation with the associated initial and boundary conditions is solved using MATLAB. The thermal performance is governed by three parameters; porosity parameter SH, thermo-geometric fin parameter M and Biot Number Bi. A parametric study is carried out to study the effects of these parameters on the porous fin transient thermal behavior. It is found that more enhancements in the porous fin performance can be achieved as SH increases especially at the final stages of the heat transfer process. The thermal efficiency of porous fins is estimated and it is observed that the efficiency decreases as the porosity parameter increases. Furthermore, the heat transfer rate from the porous fin increases by increasing both the thermogeometric fin parameter and Biot Number. In this article, recent patents on porous fins have been discussed.