Precision Machinery Research Articles

Repeated binge ethanol drinking enhances electrical activity of central amygdala corticotropin releasing factor neurons in vivo

Binge ethanol drinking is an increasingly problematic component of alcohol use disorder costing the United States approximately over $150 billion every year and causes progressive neuroplasticity alterations in numerous brain regions. However, the precise nature or machinery that underlies binge drinking has not yet been elucidated. Corticotropin releasing factor (CRF) neurons in the central amygdala (CeA) are thought to modulate binge drinking, but the specific circuit mechanisms remain poorly understood. Here, we combined optogenetics with in vivo electrophysiology to identify and record from CeA CRF neurons in mice during a repeated binge ethanol drinking task. First, we found that CeA CRF neurons were more active than CeA non-CRF cells during our binge drinking paradigm. We also observed that CeA CRF neurons displayed a heterogeneous spectrum of responses to a lick of ethanol including, pre-lick activated, lick-excited, lick-inhibited, and no response. Interestingly, pre-lick activated CeA CRF neurons exhibited higher frequency and burst firing during binge drinking sessions. Moreover, their overall tonic and phasic electrical activity enhances over repeated binge drinking sessions. Remarkably, CeA CRF units and pre-lick activated CeA CRF neurons did not show higher firing rate or bursting activity during water and sucrose consumption, suggesting that ethanol may “hijack” or plastically alter their intrinsic excitability.This article is part of the special issue on ‘Neurocircuitry Modulating Drug and Alcohol Abuse’.

Amphibian regeneration and mammalian cancer: Similarities and contrasts from an evolutionary biology perspective: Comparing the regenerative potential of mammalian embryos and urodeles to develop effective strategies against human cancer.

Here we review and discuss the link between regeneration capacity and tumor suppression comparing mammals (embryos versus adults) with highly regenerative vertebrates. Similar to mammal embryo morphogenesis, in amphibians (essentially newts and salamanders) the reparative process relies on a precise molecular and cellular machinery capable of sensing abnormal signals and actively reprograming or eliminating them. As the embryo's evil twin, tumor also retains common functional attributes. The immune system plays a pivotal role in maintaining a physiological balance to provide surveillance against tumor initiation or to support its initiation and progression. We speculate that susceptibility to cancer development in adult mammals may be determined by the loss of an advanced regenerative capability during evolution and believe that gaining mechanistic insights into how regenerative capacity linked to tumor suppression is postnatally lost in mammals might illuminate an as yet unrecognized route to cancer treatment.

Research Status and Prospects of Materials for Aero-engines in China

Aero-engine, a highly complex and precise thermal machinery, is the engine that provides the aircraft with the necessary power for flight. As the heart of aircraft, it directly affects the performance, reliability, and economy of the aircraft, and it is also an essential embodiment of a country’s scientific, technological, industrial, and national defense strength. Thus, this paper compares the material, structure, and process characteristics of China’s aero- engines and the development process and research status of high-temperature alloys in the field of aero-engines. Finally, some prospects are put forward for the development of aero-engine materials.

Structural Design and Physical Mechanism of Axial and Radial Sandwich Resonators with Piezoelectric Ceramics: A Review.

Piezoelectric ceramics are inexpensive functional materials which are widely used in sonar detection, home appliances, meteorological detection, telemetry and environmental protection and other applications. Sensors fabricated from these materials are compact and have fast response characteristics. Their underlying functional methodology is based on the direct piezoelectric effect whereby very small mechanical vibration signals are converted into electrical signals. Piezoelectric resonators are based on the reverse piezoelectric effect and they are widely used for the control of precision instruments and precision machinery, microelectronic components, bioengineering devices and other in applications requiring components to provide precision control of the relevant functional mechanism. In this paper, the structural evolution and design mechanism of sandwich resonators based on piezoelectric materials are reviewed, and the advantages and disadvantages of different structures are compared and analyzed. The goal is to provide a comprehensive reference for the selection, application and promotion of piezoelectric resonators and for future structural innovation and mechanism research relevant to sandwich resonators.

Improvements to Linear and Nonlinear Models of Machine Key Components

Precision machinery has come a long way over the years. Factories that once relied on manpower now use machines, and this development has brought with it innumerable benefits including improvements to accuracy, repeatability, productivity and efficiency. Naturally, though, machines are imperfect in that precision of a batch of machines vary slightly. On top of that, machines experience wear and tear or even break-downs. These unpredictable events can be costly to manufacturers. This is why research to better understand factors that affect a machine's precision is important. This knowledge can be used to reduce the issues that occur with machine tools and thereby maximise the efficiency and quality of production. This is the goal of Dr Yum-Ji Chan, Department of Mechanical Engineering, National Chung Hsing University, Taiwan. His research on vibration engineering, structural dynamics and the dynamics of rotors is seeking to better understand machine tools and, in doing so, improve their performance. He believes more research is required to understand the behaviour of specific components in machine tools, and he is seeking to fill this gap in knowledge. This involves understanding the vibration phenomena that occur in components in machine tools and, to do so, Chan and his team are producing accurate dynamic behaviour in machine tool models. This will, in turn, enable researchers to develop virtual machine tools that can monitor the condition of machines.

Modeling and analysis on the static stiffness of cross roller guide under five degrees of freedom

<p indent=0mm>The cross roller guide has been widely used in precision machinery, such as machine tools, and contact stiffness is an important performance index of the cross roller guide. However, no report can be found on modeling about the contact stiffness of the cross roller guide. In this study, a theoretical model for the static stiffness of cross roller guide with five degrees of freedom was established. On the basis of the Hertzian line contact theory and the Boussinesq solution of elasticity theory, the function expressions of contact force and moment between the roller and the raceway were derived using the slicing method. On this basis, the guide deformation compatible equation, physical equation, and force equilibrium equation of the guide were established, and the static stiffness of the cross roller guide with degrees of freedom was obtained by iteratively solving the equations. Then, a test rig was developed to measure the static stiffness of the cross roller guide, and the proposed model was verified by comparing the experimental data with the theoretical results. Further analysis regarding the effect of preload on the displacement and stiffness of the cross roller guide was conducted, which lays a theoretical foundation for the preload adjustment of the cross roller guide.

Design and analysis of magnetic matrix screw based on green manufacturing concept

Lead screws are the most commonly used transmission components in tool machinery and precision machinery, and are widely used in various industrial equipment and precision instruments. However, the screw tooth profile squeezes and friction causes the gear to break, tooth surface wear, tooth surface pitting and other damage, which reduces the service life of the screw; the use of a large amount of lubricants can not ignore the environmental impact. The design and research of this subject are based on the traditional ball screw mechanism, and based on the magnetic field force, the force transmission and state transformation can be realized without contact. It has significant advantages in terms of improving product service life and reducing pollution caused by lubricating fluid, which is in line with the trend of green and sustainable development. This paper analyzes the principle of non-contact magnetic matrix structure and transmission principle, and conducts finite element analysis on the parameters of screw thrust and torque. Finally, a non-contact screw experimental platform is designed to verify the screw thrust.

Transfer RNA-derived non-coding RNAs (tncRNAs): Hidden regulation of plants' transcriptional regulatory circuits

The emergence of distinct classes of non-coding RNAs has led to better insights into the eukaryotic gene regulatory networks. Amongst them, the existence of transfer RNA (tRNA)-derived non-coding RNAs (tncRNAs) demands exploration in the plant kingdom. We have designed a methodology to uncover the entire perspective of tncRNAome in plants. Using this pipeline, we have identified diverse tncRNAs with a size ranging from 14 to 50 nucleotides (nt) by utilizing 2448 small RNA-seq samples from six angiosperms, and studied their various features, including length, codon-usage, cleavage pattern, and modified tRNA nucleosides. Codon-dependent generation of tncRNAs suggests that the tRNA cleavage is highly specific rather than random tRNA degradation. The nucleotide composition analysis of tncRNA cleavage positions indicates that they are generated through precise endoribonucleolytic cleavage machinery. Certain nucleoside modifications detected on tncRNAs were found to be conserved across the plants, and hence may influence tRNA cleavage, as well as tncRNA functions. Pathway enrichment analysis revealed that common tncRNA targets are majorly enriched during metabolic and developmental processes. Further distinct tissue-specific tncRNA clusters highlight their role in plant development. Significant number of tncRNAs differentially expressed under abiotic and biotic stresses highlights their potential role in stress resistance. In summary, this study has developed a platform that will help in the understanding of tncRNAs and their involvement in growth, development, and response to various stresses. The workflow, software package, and results are freely available at http://nipgr.ac.in/tncRNA.

A Compact Review of Laser Welding Technologies for Amorphous Alloys

Amorphous alloys have emerged as important materials for precision machinery, energy conversion, information processing, and aerospace components. This is due to their unique structure and excellent properties, including superior strength, high elasticity, and excellent corrosion resistance, which have attracted the attention of many researchers. However, the size of the amorphous alloy components remains limited, which affects industrial applications. Significant developments in connection with this technology are urgently needed. Laser welding represents an efficient welding method that uses a laser beam with high energy-density for heating. Laser welding has gradually become a research hotspot as a joining method for amorphous alloys due to its fast heating and cooling rates. In this compact review, the current status of research into amorphous-alloy laser welding technology is discussed, the influence of technological parameters and other welding conditions on welding quality is analyzed, and an outlook on future research and development is provided. This paper can serve as a useful reference for both fundamental research and engineering applications in this field.

Collimated Microbeam Reveals that the Proportion of Non-Damaged Cells in Irradiated Blastoderm Determines the Success of Development in Medaka (Oryzias latipes) Embryos.

Simple SummaryStudies on teratogenesis in mammals have revealed that exposure to ionizing radiation (IR) during the pre-implantation period induces a high frequency of lethality instead of teratogenesis. Here, to elucidate the IR-induced disturbance of embryonic development when IR exposure occurs during the pre-implantation period, we utilized medaka as a vertebrate model for clear observation of developmental process for its transparency. Blastula embryos exposed to IR with a lower lethal dose (gamma-rays) transiently exhibited smaller brains than those of sham-controls, however, their brain size restored equally to those of controls until hatching. We then conducted targeting irradiation, which allowed various proportions of blastoderm cells to be exposed to IR (carbon-ions), and identified that the loss of approximately 10% or less of blastoderm was compensated by the remaining non-damaged blastoderm cells even though they transiently exhibited smaller brains. In contrast, when IR exposure occurred during the late embryogenesis period, 3 days post fertilization, the brain size was not completely restored until hatching even with a lower lethal dose. Collectively, blastoderm cells with IR-induced injury undergo transient delays in brain development, however, can avoid teratogenesis at hatching presumably for their pluripotency whereas embryos during the late embryogenesis period lack the ability to do so.It has been widely accepted that prenatal exposure to ionizing radiation (IR) can affect embryonic and fetal development in mammals, depending on dose and gestational age of the exposure, however, the precise machinery underlying the IR-induced disturbance of embryonic development is still remained elusive. In this study, we examined the effects of gamma-ray irradiation on blastula embryos of medaka and found transient delay of brain development even when they hatched normally with low dose irradiation (2 and 5 Gy). In contrast, irradiation of higher dose of gamma-rays (10 Gy) killed the embryos with malformations before hatching. We then conducted targeted irradiation of blastoderm with a collimated carbon-ion microbeam. When a part (about 4, 10 and 25%) of blastoderm cells were injured by lethal dose (50 Gy) of carbon-ion microbeam irradiation, loss of about 10% or less of blastoderm cells induced only the transient delay of brain development and the embryos hatched normally, whereas embryos with about 25% of their blastoderm cells were irradiated stopped development at neurula stage and died. These findings strongly suggest that the developmental disturbance in the IR irradiated embryos is determined by the proportion of severely injured cells in the blastoderm.

Bolt Tightening Methods on the Combined Surface of Assembly Structure

Machine tools are assembled by thousands of components. The surface between two components is the mating surface. The bolt tightening methods will affect the stress and deformation of mating surface which influences the accuracy and rigidity of machine tools. In the precision machinery industry, if the structure needs to tighten in line such as linear guideway, the senior engineers will tighten the bolts from sides to the middle or middle to sides instead of tightening in order. Furthermore, engineers use two-step of tightening rather than one-step of tightening. Based on their experience, these tightening methods will reduce the stress of mating surface and increase the rigidity of entire structure. In this study, the three bolts tightening model is used to investigate these tightening methods. Three bolts tightening CAD model is created by using the SolidWorks software. The finite element analysis is used the ANSYS workbench R19 software to simulate the bolt tightening methods (tightening sequences and pre-tightening force ratio) on the mating surface and entire model. From the simulation results, the minimum stress is observed in the tightening sequence from sides to middle and maximum stress is obtained in the tightening sequence in order. The experimental results of bolt tightening sequences match the simulation results. The stresses of mating surface and entire model drastically decrease when the tightening step is two-step of tightening. In two-step tightening process, the pre-tightening force ratio 1:1 is the optimal tightening methods for reducing the stress of mating surface compared to another pre-tightening force ratio.

The influences of corrosion on the tightening and anti-loosening properties of a flank-locking precision locknut

ABSTRACT Locknut is a critical component used in the precision machinery and its stable service performance over a long period of time in a variety of different environments presents a crucial challenge. In this study, a flank-locking precision locknut was pretreated in an immersion corrosion of 5 wt% NaCl solution to simulate the possible corrosion effects. The tightening and loosening of the locknut after 0-, 1-, 2- and 4-h corrosion treatments, respectively, was tested according to the ISO 2320 Standard. An in-house test setup with horizontal configuration was employed in measuring the torque–axial force characteristics under loading–unloading cycles. It was found that the corrosion of the locknut accelerated after 1-h immersion. The corroded specimens after 2- and 4-h treatment demonstrated more variance in measured tightening and loosening torques than their less corroded counterparts. However, after five loading–unloading cycles, the variance in measured torque decreased and the associated torque constants became more stable. Moreover, the torque constants were ∼10% higher for the 2- and 4-h corrosion-treated locknuts than their pristine counterpart. The surface morphology after corrosion and friction wear was closely related to the measured testing results.

Fusion of Slippery Interfaces and Transistor-Inspired Architecture for Water Kinetic Energy Harvesting

Download : Download high-res image (171KB) Download : Download full-size image Wanghuai Xu is currently a doctoral candidate in the Department of Mechanical Engineering at the City University of Hong Kong and the Department of Precision Machinery and Precision Instrumentation, at University of Science and Technology of China. His research interest focuses on water-based energy harvesting, electrical phenomena at the water-solid interface and bioinspired surface engineering. Download : Download high-res image (243KB) Download : Download full-size image Zuankai Wang is a Professor in the Department of Mechanical Engineering at the City University of Hong Kong. He received his PhD degree in mechanical engineering from Rensselaer Polytechnic Institute, USA, in 2008, his MS degree in microelectronics from Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, in 2003, and BS degree in mechanical engineering from Jilin University, China, in 2000. His research mainly focuses on nature-inspired materials and devices.

Kinematic error analysis of the rotor vector gear reducer with machining tolerances

The rotor vector (RV) gear reducer is a mechanism used for motion and torque transmission. With characteristics similar to a traditional cycloidal gear drive, it has been popularly applied in precision machinery because of its high-speed reduction ratio, large torque capacity, and high efficiency. In this work, we aim to analyze the kinematic error (transmission error) of the RV reducer with manufacturing and/or assembly tolerances. Formulae for the kinematic error are established by using the theory of gearing as well as tooth contact analysis. Subsequently, sensitivities of the kinematic error with respect to various design parameters are investigated. Lastly, a process to simulate the distribution of maximum kinematic errors of the gear reducer with various tolerance grades of the parts is developed via Monte Carlo method. It is shown that through selected tolerance control on the machine parts, the accuracy of the gear drive can be retained. The results of this work can be useful for controlling the manufacturing precision on the machine parts and assessing the overall accuracy of the mechanism in the design phase.

Ebara builds vacuum pump overhaul facility in Dresden

Ebara Precision Machinery Europe (EPME) is investing €1.6 million in a new centre in Dresden, Germany for the overhaul of dry vacuum pumps.

A General Framework for Aliasing Corrections of Inductive Oil Debris Detection Based on Artificial Neural Networks

Induction-based oil debris detection methods have shown a great potential for providing non-invasive monitoring and measurement to prolong the life of precise machinery. However, the superimposition of the induced voltages by the multiple debris particles prevents these methods from being more accurate. An artificial neural network is employed in this work to establish a general corrective framework aiming at solving the modeling and adaptability problems for different sensors, and a hybrid detection strategy is proposed to further reduce the detecting error under different aliasing conditions. A simulative test using two sinusoidal waveforms is conducted to validate the performance of the proposed method. Finally, an experiment is carried out with known oil debris concentrations ranging from 5 mg/L to 100 mg/L, and the linearity of the detected signals under the given concentrations is used to evaluate the performances of different methods. The results indicate that the maximum error by the proposed measurements is less than 20%, while for the non-corrected measurements, the maximum error is over 40%.

초정밀 가공을 위한 ECTS 제어에 관한 연구

In the framework of the 4th industrial revolution, modern machine-building rapidly converges with IOT technology. This requires very high precision machining of the parts and assemblies, such as electronics, vehicle and components, agricultural and construction machines, optical instruments, and machine tools. However, high precision machinery is quite expensive, and there exists a general need for low-cost equipment. While many researchers are working on this, their major focus is on cutting tools. This study aimed to compensate for errors and enhance machinery precision by adding a servo controller to the processing unit. Consequently, the study is on servo control and processing precision for processing utilizing ECTS (Error Compensation Tool Servo) to compensate for errors.

A thermal model for real-time temperature forecast of rolling linear guide considering loading working conditions

Thermal behaviors significantly affect the contact stiffness and position accuracy of the rolling linear guide, which worsen the performance of the precision machinery. In this paper, based on the modified lumped capacitance method (MLCM) and finite element method (FEM), a thermal model of rolling linear guides has been formulated in terms of the geometric parameters, friction, gyroscopic moment, and loading conditions. Experimental results show that the thermal model can well predict the real-time temperature variation under different working conditions. Further analysis shows that, the applied vertical load, carriage velocity, and toque load significantly influence the temperature variation of linear guides, while the influence of the torque load on temperature variation decreases with increasing vertical load levels. Besides, the reasons of the steady-state temperature variation considering the load distribution model are also discussed.

Foreword

The 1st International Conference on Precision Machinery and Manufacturing Technology 2015 (ICPMMT) was held at Howard Beach Resort, Kenting, Taiwan on May 22-24, 2015. The papers submitted to ICPMMT 2015 were recommended to KEM (EI Compendex) through the peer reviewing process.The 2nd ICPMMT 2017 was held at Howard Plaza Resort, Kenting, Taiwan on May 19-21, 2017. And the 3rd ICPMMT 2018 has been taken place in Auckland, New Zealand on 4-8 February, 2018. After conference, all papers submitted to ICPMMT 2017 and 2018 were recommended to MATEC Web of Conferences, Open-access Journal in Materials science, Engineering and Chemistry (Google Scholar, CAS, EI Compendex, Inspec, DOAJ, Web of Science, Scopus). All papers through the peer reviewing process can be published in MATEC Web of Conferences. The 4th ICPMMT 2019 was back to Howard Plaza Resort, Kenting, Taiwan on May 24-26, 2019. All papers through the peer reviewing process can be published Key Engineering Materials and IOP: Materials Science Engineering with EI Compendex. This year the 5th ICPMMT 2020 is back to Crowne Plaza, Auckland, New Zealand on 3-7 February 2020. Some papers through the peer reviewing process can be published in Solid State Phenomena and Journal of Physics: Conference Series with EI Compendex. List of Conference Chair, Steering Committee and Scientific Committee are available in this pdf.

Mechanism Research and Discussion of the Quality of Precision Machining of a Fifth-order Variable-diameter Pipe Using Abrasive Flow

The solid-liquid two-phase abrasive flow precision machining technology is widely used in aerospace, precision machinery, the automotive industry and other fields, and is an advanced manufacturing technology that effectively improves the inner surface quality of workpieces. In this paper, the fifth-order variable-diameter pipe parts are researched. By discussing the collision between the abrasive particles and the wall surface, it is revealed that the material removal of the workpiece is caused by plastic deformation, and the mechanism of precision machining of the abrasive flow is clarified. Through numerical analysis and experimental research, it is found that the incident angle can affect the precision machining quality of the abrasive flow. When the inlet velocity of the abrasive flow is 45 m/s and the incident angle is 15°, the fifth-order variable-diameter pipe can obtain the best surface quality. Abrasive flow machining improves the surface quality of small holes better than that of large holes. To obtain uniform surface quality, it is necessary to use two-way machining to perform abrasive flow machining. The surface texture of the fifth-order variable-diameter pipe workpiece after precision machining by abrasive flow becomes clear and smooth, and the surface quality is significantly improved. The research results can provide theoretical guidance and technical support for the popularization and application of solid-liquid two-phase abrasive flow precision machining technology, with significant academic value and application value.