Precision Equipment Research Articles

Online learning method based on artificial neural network to optimize magnetic shielding characteristic parameters

Magnetic shielding plays an important role in magnetically susceptible devices such as cold atom clocks, atomic interferometers and other precision equipment. The residual magnetic field in a magnetic shield under a varying external magnetic field can be calculated by the Jiles-Atherton (J-A) hysteresis model and magnetic shielding coefficient. According to the calculation results, the variation of internal magnetic field can be compensated for the active compensation coils. However, it is difficult to practically obtain the exact values of the five magnetic-shielding-related parameters in the J-A hysteresis model and the other two magnetic-field-attenuation-related parameters. It usually takes a lot of time to match the parameters manually according to the measured hysteresis loop and it is difficult to ensure that the final parameters are the global optimal values. The machine learning method based on artificial neural network has been used as an efficient method to optimize the parameters of complex systems. Owing to the powerful computing capability of modern computers, using the artificial neural network to optimize parameters is usually much faster than manual optimization method, and has a greater probability of finding the global optimal parameters. In this paper, the five J-A parameters and the other two parameters relating to magnetic field attenuation are optimized by the method of online learning based on artificial neural network, and the residual magnetic field in the magnetic shield is predicted under the simulated satellite magnetic field environment. By comparing the measured residual magnetic field with the predicted value, it is found that the machine learning method can optimize the magnetic shielding characteristic parameters more quickly and accurately than the manual optimization method. This result can not only help us to compensate for the magnetic field better and optimize the parameters of our cold atom system, but also validate the application of neural network in a multi-parameter physical system. This proves that the in-depth learning neural network can be conveniently applied to other physical experiments with multi-parameter interaction, and can quickly determine the optimal parameters needed in the experiment. This application is especially effective for remote experiments with slow response to parameter adjustment, such as scientific experiments carried out on satellites or deep space.

Testing Cooling Technology

The increasing importance of thermal management in electric vehicle powertrain development calls for sophisticated and precise testing equipment

Effect of Structure Parameters on Polycal Wire Rope Isolator Stiffness‐Damping Characteristics

Wire rope isolators are mainly used to isolate vibration and protect precise equipment. However, the issue of regulation of vibration isolators taking into account the nonlinearity of their characteristics was poorly understood in the modern literature. In this paper, the influence of structural parameters (diameter ratio and lay pitch of the single strand, and lay pitch and bending radius of the wire rope) on stiffness‐damping characteristics of the Polycal WRI was investigated by the simplified finite element analysis method. The stiffness and damping prediction models including structural parameters and material properties were established. The results showed that the stiffness‐damping characteristics were the best; when the diameter ratio of wire strand was 1.1, the inside layer wire pitch length was 6 times the diameter of the wire strand, the outside layer wire pitch length was 11 times the diameter of the wire strand, the pitch length of the wire rope was 7.5 times its diameter, and the bending radius was equal to 46.5 mm. The errors of the prediction for prestiffness and softened stiffness were within 5%, and the errors of prediction for the energy dissipation coefficient were within 10%.

Continuous IEQ monitoring system: Performance specifications and thermal comfort classification

The quality of buildings can be assessed in terms of the indoor air quality, thermal comfort, lighting quality, acoustic comfort afforded the occupants, collectively referred to as Indoor Environmental Quality (IEQ). A major barrier to a more thoroughly representative audit of actual IEQ performance are the expense and complexity of the measurement instrumentation required. Rapid developments in sensor technology in recent years present the opportunity for continuous and pervasive IEQ monitoring to deliver truly representative characterisations of building performance at a modest cost. The last remaining obstacle to realising these developments seems to be a concern about instrument accuracy.In this paper we test the performance of a low-cost IEQ monitoring system (SAMBA) introduced in an earlier paper. Calibration data from 100 devices was analysed to calculate the standard error of the estimate as a measure of equipment accuracy. Those performance specifications were used in a Monte Carlo simulation based on measurements of thermal comfort parameters from 24 office buildings. Performance measures suggests the low-cost system, whilst not as accurate as laboratory equipment, is more than sufficient for building IEQ diagnostics and compliance assessments. Furthermore, the results of the Monte Carlo simulation show that continuous monitoring systems are better at characterising long-term performance than ad hoc measurement strategies using precision equipment. Low-cost pervasive monitoring technologies therefore offer a unique opportunity to improve our quantitative understanding of, and response to, indoor environmental quality issues.

Synthetic granite composite for precision equipment structures

The structure is a component that plays an extremely important role in the equipment’s performance, it must withstand efforts without compromising the function, receive and transfer heat, dampen vibrations and position the elements, as well as promote ergonomics and aesthetics. In lightweight and precision equipment’s the raw material used must also allow thin walls, rigid, resistant and low density. The objective of the present work is the development of a synthetic granite composite for manufacturing of equipment’s structures. For this, an abundant Brazilian granite, a high strength epoxy resin and segmented carbon fibers were selected as materials. Test specimens, with maximized packing with granite gravel less than 2.0 mm were fabricated and tested for tensile strength, compression, flexural, damping, hardness, dilatometry, thermal conductivity and density. The maximized composition supported flexural stresses above 42 MPa, without fiber reinforcement and 51 MPa with carbon fiber reinforcement. The damping coefficient was about 7 times higher than cast iron, coefficient of thermal expansion of 1.4E-05 m/m.K, thermal conductivity coefficient of 1.2 W/m.K and density of 2.1 g/cm³. The developed composite showed potential for refining structures, with ease of molding of thin-walled elements, use of inserts, re-machining, providing economical manufacture of single parts, and is still able to perform the function with high damping coefficient and low weight. Keywords: Synthetic granite, composite, machine structure, damping

Research on the precision loss of ball screw with short-time overload impact

Ball screw is the driving functional component most frequently used for the precision equipment. To a certain extent, the transmission accuracy of precision equipment is affected by the position error of ball screw caused by the elastic–plastic deformation between ball and raceway under the overload impact. This article aims to investigate the precision loss of ball screw considering short-time overload impact. A novel precision loss model combining the Hertzian and Thornton contact theories is established to describe the variations in the axial deformation depths. Thus, the axial precision loss can be defined as the differential value between the initial no-loading travel variations and the loading stroke variations caused by the axial plastic deformation of raceway. Meanwhile, the maximum stress and the residual plastic deformation for four couples of ball-raceway materials are analyzed. Furthermore, the relationship between the precision loss and the elastic–plastic deformation is studied by the theoretical analysis and experiments. The results show that the position and precision is affected indeed by the contact deformation. The position and precision loss of the nut relative to the screw increases with the increase in the axial load. The results can help to provide the prediction for the precision life of ball screw operating in high-load condition.

Small Farms, Big Plans: Mechanization and Specialization as Measures of “The Middle”

AbstractOver the past decades, farms in the U.S. have become fewer and larger. Along with the trend of increasing in size, farms have become increasingly specialized, producing fewer products per farm, and mechanized, relying on precision equipment rather than human labor. The concepts of farm size, specialization, and mechanization, appear to be tightly articulated. As a farm increases in size, it becomes more specialized and reliant on equipment. Conversely, a smaller farm is more diverse and labor‐intensive. This paper attempts to disconnect these three concepts by first showing where anthropologists have questioned the inevitability of increasing specialization and mechanization as farm size increases, particularly in the years following the 1980s farm crisis. Second, using ethnographic examples from local food producers in Iowa, this paper explores the utility of specialization and mechanization, even on very small acreages. Using ethnographic analysis to disentangle specialization and mechanization with farm size can help us reconceptualize what we mean by the agricultural middle, focusing on farm practices, rather than farm size.

Comparative studies of oxygenated fuel synthesis with diesel from the measurements of density, speed of sound and refractive index

An experimental investigation on the feasibility and relevance of the tri fuel blends of ethanol and dibutyl ether with diesel was studied to replace pure diesel. The solubility of the ethanol and dibutyl ether with a percentage of 25% and 75% resulted with no phase separation, found miscible and stable with diesel at any percentage. However, the properties such as densities and refractive index experimentally verified for different blend ratios. A density of test samples with various compositions was tested. High precise equipment is engaged to analyze the density, speed of sound, refractive index for various fuel compositions. The temperature ranges between 298 K and 343 K show a greater impact on variation in the fuel properties. Density, speed of sound, refractive indices measured as a function of the temperature with an accuracy of ± 0.001 and ± 0.0001. Further, the validation of experimental method has been tested using Lorentz–Lorenz (L–L) analysis with a deviation of 0.4%. The uncertainty for fluid velocity is ± 0.3 m s−1, and the experimental estimated excess molar volume uncertainty is 2 × 10−3 cm3 mol−1. The substantiation of intermolecular interactions between the liquids is found to be significant in both experimental and prediction analysis of each sample. The exergy destruction specifies with 46% which includes the air flow and chemical heat energy transfer losses.

Data center holistic demand response algorithm to smooth microgrid tie-line power fluctuation

With the rapid development of cloud computing, artificial intelligence technologies and big data applications, data centers have become widely deployed. High density IT equipment in data centers consumes a lot of electrical power, and makes data center a hungry monster of energy consumption. To solve this problem, renewable energy is increasingly integrated into data center power provisioning systems. Compared to the traditional power supply methods, renewable energy has its unique characteristics, such as intermittency and randomness. When renewable energy supplies power to the data center industrial park, this kind of power supply not only has negative effects on the normal operation of precision equipment, such as CPU/GPU chips and hard disk, in data center, but it would also impact the stability of the utility power grids operation. To solve this problem, this paper presents a novel tie-line power fluctuation smoothing algorithm with consideration of data center’s holistic demand response. The contributions of this paper are: (1) overcoming the limitations of treating IT load as uncontrollable workload in the traditional demand response research, we design a data center resource scheduling model to realize IT load demand response controllability; (2) two novel mechanisms are proposed: (i) the server cluster workload scheduling method with time shift mechanism, and (ii) the data center UPS (Uninterruptible Power Supply) energy storage dynamic response mechanism. (3) Combining these two mechanisms as holistic demand response of data center, we present a tie-line power fluctuation smoothing algorithm to improve power supply reliability, which is beneficial to both the high density and precision IT equipment in the data center and the utility power grid. In the experiments, the results show that the new algorithm can effectively regulate the tie-line power fluctuations under different server cluster utilization ranges and scenarios of large-scale penetration of distributed renewable energy scenarios. The new algorithm is hence able to contribute beneficially to the reliability and stability of intelligent industrial park micro-grid and utility power grids.

Study of the correlation between outdoor and indoor electromagnetic exposure near cellular base stations in Leuven, Belgium

A measuring campaign for the assessment of electromagnetic radiation near base stations in the city center of Leuven, Belgium, has been carried out. The main objective of this assessment is to study the correlation between the outdoor and the indoor exposure produced by cellular base stations and to investigate the changes of electromagnetic exposure within a typical day and over 1 month in the vicinity of these base stations. The study was also carried out as a function of location and time using highly precise measurement equipment. The measurements were performed in both public and private areas in sixty (30 indoor and 30 outdoor) different locations in Leuven. The measurement was focused on mobile communication networks: GSM (Global System for Mobile Communication, 900 MHz and 1800 MHz) and UMTS (Universal Mobile Telecommunications System, 2110 MHz) were the frequency bands of interest. The data at these frequencies were extracted from raw measurements in the 824–2170 MHz frequency band. The results show that all analyzed locations are in compliance with the exposure limits recommended by ICNIRP (International Commission on Non-Ionizing Radiation Protection) and that the (maximum) indoor exposure correlates to the outdoor exposure with a factor of about 0.5.

High precision (Advanced) angle metrology: pushing the limits for nanoradian uncertainty demands

Precise angle measuring devices – such as angle encoders, angle interferometers, small angle generators and autocollimators – are extensively used in various applications where high precision is demanded. Recently, an angle metrology project supported under European Metrology Research Programme (EMRP) has been completed. This project has made a significant contribution to traceable angle metrology targeting at nanoradian uncertainty (less than 50 nrad) for stringent demands and achieved milestones. It has provided novel methods, tools, instruments, guides and knowledge that will help to ensure use of precise angle metrology equipment for the demands which have not been answered before. Some of the new devices are already commercially available and have been started to be used for critical needs. This paper gives highlights of the project’s outputs and inform the community about recent developments in high precision advanced angle metrology.

Study of a Teaching Method to Grow the Control Engineer of Precision Apparatus

This paper proposes a teaching method and material to learn the control engineering in an industrial company. It is very important to teach engineers who have knowledge of control engineering in a company which is developing high precision equipment. However, there were not teaching curriculum and material that are suitable for beginner and intermediate engineers. Particularly, it is important the teaching material is low cost and linear system. Moreover, it is good to be the teaching material that is able to control with less programs. This paper proposes the one axis stage system that adopts Arduino ® which is low-priced microcomputer for education and hobby. Arduino ® is suitable for education of beginner and intermediate engineers because it can control peripheral devices with less programs. Then, engineers are not confused by making complicate programs. Therefore, engineers can learn the basics of control engineering surely because the one axis stage system is comprised of only linear elements. Here, even though the low-priced position sensor has a non-linear characteristic, it seems to be the linear sensor because it is linearized and encapsulated by Lagrange interpolation method. Engineers attending the lecture do not need to care non-linearity. This paper describes the one axis stage system and the teaching curriculum using the one axis stage. Then, this paper describes growing up of an engineer via developing of the active damping system. An engineer improved a repeatability of measurement accuracy of the LSI line width by developing of an active damping system.

A fast and practical method for initial diagnosis of Piscinoodinium pillulare outbreaks: piscinootest

ABSTRACT: The dinoflagellate Piscinoodinium pillulare is a parasite with low parasitic specificity and unspecific geographical distribution. This research reported a simple and practical method - the principle of spontaneous sedimentation - to identify the presence of P. pillulare during massive infestations which does not require using precision equipment. Agitation in water of the gill arches of infested fish will elicit, after a period of rest, recording the accumulation of trophonts in the bottom of flasks. The method was applied during outbreaks of P. pillulare in tambaqui, Colossoma macropomum and matrinxã, Brycon amazonicus, in fish farms of the Amazon region and proved to be effective.

Numerical algorithms of marine diesel engine instantaneous speed based on Hilbert-Huang Transform

As is known to all, there are lots of measurement noises and ambient noises among diesel engine instantaneous speed signal, for the warship engine room environment is not convenient to install precise equipment, such as photoelectric encoder etc. The instantaneous speed signal processing method of diesel engine should be thoroughly studied. The Hilbert-Huang transform is introduced to decompose the instantaneous speed signal by EMD empirical mode and to analyze the spectrum. The IMF component which affects the fluctuation of the speed is superimposed to obtain the HHT (Hilbert-Huang Transform)-based filtering curve. Then a low pass filter is designed to solve the attenuation signal problem in the useful signal based on the HHT filter. Subsequently the filter technical parameters are determined according to the spectrum analysis of the IMF component. Experimental results show that the filtering effect of the designed algorithms is fairly well.

Improving the Formability of Metals in Microforming

Microforming is effective to economically and precisely manufacture metallic micro products that have extensive applications in medical devices, precision equipment, communication devices, micro-electromechanical systems and micro fluidics systems. However, the formability of metals in microforming would be greatly impacted due to the unique characteristic of size effects existed in microscale. This paper has introduced the approaches that are applicable to the improvement of formability of metals in microforming, which will be helpful for those who are studying and working on metallic micro products and their microforming technologies.

High thermal conductivity liquid metal pad for heat dissipation in electronic devices

Novel thermal interface materials using Ag-doped Ga-based liquid metal were proposed for heat dissipation of electronic packaging and precision equipment. On one hand, the viscosity and fluidity of liquid metal was controlled to prevent leakage; on the other hand, the thermal conductivity of the Ga-based liquid metal was increased up to 46 W/mK by incorporating Ag nanoparticles. A series of experiments were performed to evaluate the heat dissipation performance on a CPU of smart-phone. The results demonstrated that the Ag-doped Ga-based liquid metal pad can effectively decrease the CPU temperature and change the heat flow path inside the smart-phone. To understand the heat flow path from CPU to screen through the interface material, heat dissipation mechanism was simulated and discussed.

Direct speed of sound measurement within the atmosphere during a national holiday in New Zealand

Measuring the speed of sound belongs to almost any physics curriculum. Two methods dominate, measuring resonance phenomena of standing waves or time-of-flight measurements. The second type is conceptually simpler, however, performing such experiments with dimensions of meters usually requires precise electronic time measurement equipment if accurate results are to be obtained. Here a time-of-flight measurement from a video recording is reported with a dimension of several km and an accuracy for the speed of sound of the order of 1%.

Ready-to-eat meat products as a source of Listeria monocytogenes

Abstract In 2015 in the European Union member states listeriosis caused 270 deaths. Food is the route of transmission in 99% of all human infection cases. Several studies from different countries have shown that the presence of Listeria monocytogenes in food can be as high as 58.3%. One of the most important ways to protect food from these microorganisms is to prevent the spread of the bacteria at processing plants at different stages of food production chain. The ability of L. monocytogenes to survive in extreme conditions and to form biofilms on various surfaces is a significant challenge for food safety. Removal of these bacteria from niches in processing plants is difficult and requires the use of sanitisers and precise equipment cleaning. The presence of L. monocytogenes in processing environment at slaughterhouses, deli meat factories or in retail may be a reason of cross-contamination. Proper hygienic systems applied by workers in food preparing places and knowledge about different routes of spreading of these bacteria may effectively decrease the risk of food contamination. Standardised legal regulations and control of meat product manufacture should be a fundamental way to protect food from L. monocytogenes contamination.

Ready-to-eat Meat Products As a Source of Listeria Monocytogenes

In 2015 in the European Union member states listeriosis caused 270 deaths. Food is the route of transmission in 99% of all human infection cases. Several studies from different countries have shown that the presence of Listeria monocytogenes in food can be as high as 58.3%. One of the most important ways to protect food from these microorganisms is to prevent the spread of the bacteria at processing plants at different stages of food production chain. The ability of L. monocytogenes to survive in extreme conditions and to form biofilms on various surfaces is a significant challenge for food safety. Removal of these bacteria from niches in processing plants is difficult and requires the use of sanitisers and precise equipment cleaning. The presence of L. monocytogenes in processing environment at slaughterhouses, deli meat factories or in retail may be a reason of cross-contamination. Proper hygienic systems applied by workers in food preparing places and knowledge about different routes of spreading of these bacteria may effectively decrease the risk of food contamination. Standardised legal regulations and control of meat product manufacture should be a fundamental way to protect food from L. monocytogenes contamination.

Determination of the frequency characteristics of a magnetorheological elastomers vibration control platform

To reduce the effects of external vibration disturbances, various methods of vibration protection are used, including active, semi-active and passive vibration isolation systems. For vibration isolation of modern precision equipment, it is proposed to use a plate-like vibration isolation based on magnetorheological elastomers. Studies of the frequency characteristics of this platform and its management capabilities are necessary to determine the effective modes of operation of the platform. Thanks to the tests on the vibration electrodynamic installation, the dependence of the coefficient of transfer of the amplitude of vibration displacement on the oscillation frequency at different currents was obtained and showed that the effective range of vibration isolation is from 38 to 100 Hz.