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The problem of the technological quality of elements is one of the primary problems of modern machine production. In many cases, elements are made from new construction materials with specific properties considered to have poor machinability in cases where conventional technologies are applied. Thus, there is a need to identify the capabilities of new technologies, including the technology of cutting with a high-pressure abrasive water jet for the production of elements made of multi layered materials, while observing qualitative machining requirements. This paper presents the results of studies of the accuracy of production of elements with a complex shape made of Dibond composite board The measure of the accuracy of production, independent of dimensional accuracy, was assumed to be the size of chamferring on the side surface of the cut element caused by a specific mechanism of material decohesion occurring under the influence of water jet technology. In cases where composite boards are cut, depending on assumed conditions, it is possible to shape the side surface of an element with a positive, negative, or neutral (zero) wall inclination (side of the element). In the process of cutting, specific errors in the shape of the element occur and appear on curved fragments of the object or in discontinuous areas of the profile (e.g. transition from a straight fragment to an arc fragment); this is caused by a shift in the exit of the high-pressure abrasive water jet from the object relative to the point of entry. Consequently, selection of cutting parameters for the water jet method for elements with complex shapes is, in essence, a compromise between the obtained inclination of the wall of the processed element and the required surface coarseness, and between the required (acceptable) inclination of the wall of the element or lack thereof and the obtained coarseness of the element's surface. Thus, in the outlined problem, it is not possible to simultaneously obtain two satisfactory criterial quantities of element quality, that is, accuracy of shape and requisite coarseness of the surface of the machined element, if the water jet method is applied for the purpose of machining composite board. This article related to a paper at PCM-CMM-2019.

Nanopositioning techniques present an important capability to support the state-of-the-art synchrotron radiation instrumentation research for the Advanced Photon Source (APS) operations and upgrade project. To overcome the performance limitations of precision ball-bearing-based or roller-bearing-based stage systems, compact nanopositioning flexure stages have been designed and developed at the APS for x-ray beamline instrumentation applications. Recent progress of such stages development is discussed in this paper, which includes: rotary flexure stages with degrees travel range and 10-nrad-level resolution for x-ray monochromators and analysers, tip-tilting flexure stages for K-B mirror based nanofocusing hard x-ray optics, and linear vertical and horizontal nanopositioning flexure stages with centimeter-level travel range and microradian-level motion trajectory reproducibility for x-ray optics and sample manipulation. The mechanical design and preliminary test results are described in this paper.

The development of spacecraft large-sized reflectors is one of the most urgent issues for the space industry. The reflector structure is to meet such principle criteria as high accuracy in reflective surface configuration and weight. The accuracy in the reflective surface configuration during continuous operation is ensured by the control system. The authors suggest using piezo motors in the control system. The motors of such type of certain small mass-overall characteristics can create high force. This paper presents a new piezo motor design and its operation. A mathematic model of piezo motor operation modes has been worked out which became the basis for setting new designed piezo motor operation modes depending on different loads. The results of the experimental tests of the new designed piezo motor confirmed the results of the theoretical calculations.The development of spacecraft large-sized reflectors is one of the most urgent issues for the space industry. The reflector structure is to meet such principle criteria as high accuracy in reflective surface configuration and weight. The accuracy in the reflective surface configuration during continuous operation is ensured by the control system. The authors suggest using piezo motors in the control system. The motors of such type of certain small mass-overall characteristics can create high force. This paper presents a new piezo motor design and its operation. A mathematic model of piezo motor operation modes has been worked out which became the basis for setting new designed piezo motor operation modes depending on different loads. The results of the experimental tests of the new designed piezo motor confirmed the results of the theoretical calculations.

As various international and government institutions have decreed that electronic devices must adhere to electromagnetic safety standards before they enter the market, electromagnetic shielding has become an important aspect of design considerations. Various materials at different price points have specific characteristics that may cause them to become either optimal or ill-fitting for specific applications, however, testing their shielding capability can be difficult without the expensive equipment in testing facilities. In this paper, a handheld electromagnetic (EM) meter was used in a simplified test set up to assess the shielding effectiveness of 6 shielding materials: silver sleeve, steel mesh, conductive ABS, Al tape, and Al metallised film. Silver sleeve, Al tape, and Al metallised film were chosen to shield a robotic medical device based on their shielding capability, cost-effectiveness, and design flexibility. The CISPR 11 radiated emissions test results of the robotic medical device validated the shielding effectiveness of the materials chosen showing that the handheld EM meter was able to assess the materials’ shielding capability.As various international and government institutions have decreed that electronic devices must adhere to electromagnetic safety standards before they enter the market, electromagnetic shielding has become an important aspect of design considerations. Various materials at different price points have specific characteristics that may cause them to become either optimal or ill-fitting for specific applications, however, testing their shielding capability can be difficult without the expensive equipment in testing facilities. In this paper, a handheld electromagnetic (EM) meter was used in a simplified test set up to assess the shielding effectiveness of 6 shielding materials: silver sleeve, steel mesh, conductive ABS, Al tape, and Al metallised film. Silver sleeve, Al tape, and Al metallised film were chosen to shield a robotic medical device based on their shielding capability, cost-effectiveness, and design flexibility. The CISPR 11 radiated emissions test results of the robotic medical device validated th...

The pulsed plasma thruster (PPT) is a potential electric thruster for microsatellites. One important content of PPT performance research is the measurement of micro-thrust and micro-impulse. This paper summarizes the 4 typical dynamic measuring systems at home and abroad, which include the single pendulum type, the torsion pendulum type, the cantilever type and the balance type. In the paper, the structure principle, measurement performance, advantages and disadvantages of various configurations are compared and analyzed. The development process of each micro-thrust and micro-impulse measurement technology is summarized, and its developing trend is prospected.

The advent of Automated Fiber Placement (AFP) systems have aided the rapid manufacturing of composite aerospace structures. One of the challenges that AFP systems bring is the variability of the deposited prepreg tape layers, which are prone to gaps, overlaps and twists. The current detection method used in industry involves halting fabrication and performing a time consuming visual inspection of each tape layer. Typical AFP systems use a quartz lamp to heat the base layer to make the surface tacky as it deposits another tape layer. The innovation discussed in this paper is to use the preheated base layer as a through transmission heat source and inspect the newly added tape layer in situ using a thermographic camera mounted onto the AFP structure. Such a system would not only increase manufacturing throughput by reducing inspection times, but would also aid in process development for new structural designs or material systems. To this end, a small thermal camera was mounted onto an AFP robotic research platform at NASA, and thermal data was collected during typical and experimental layup operations. The data was post processed to reveal defects such as tow overlap/gap, wrinkling, and peel-up. Defects that would have been impossible to detect visually were also revealed in the data, such as poor/loss of adhesion between plies and the effects of vacuum debulking. This paper will cover the results of our experiments, and the recent progress on the data reduction algorithms in preparation for machine learning development.

In the aviation industry high-performance thermoplastic materials have started to replace metals in many fields. In this paper a novel pipe-extrusion process for high-temperature polyetherimide (PEI) is presented with special emphasis on the calibration and cooling of the pipes. Both the weight advantage over stainless steel pipes and the price advantage over titanium confirm a high potential of thermoplastic pipe systems in the aviation sector. The pipe systems installed in aircrafts are characterised by many variations in terms of geometries (diameter, wall thickness, etc.). The design diversity of thermoplastics can be used to exploit additional potentials in terms of mass savings, production efficiency and cost reduction. In order to address the forecasts of growing aviation transport capacity and aircraft production volume especially the production efficiency will be stronger focused in long term. This paper describes an approach to extrude PEI pipes with variable wall thickness. Thus, studies were conducted to analyse the effects of parameter changes on the pipe geometry and surface quality. In addition to that special emphasis was laid on the temperature profiles of the pipes inside the calibration system. An approach is presented to locally adjust the wall thickness of the pipes in longitudinal direction for defined geometry changes. The results of the simulation and the measurements led to an in-depth understanding of the process parameters needed to extrude PEI pipes with variable wall thickness.

Electrohydrodynamic inkjet printing (e-jet printing) is one type of micro/nano scale 3D printing techniques that automatically deposit functional materials to form 3D structures on the substrate. Unlike traditional thermal or acoustic inkjet printing, e-jet printing utilizes high electrical forces for the ink to overcome surface tension at the tip of micro needles. The droplets and filaments coming out from the needle have dimensions much smaller than the dimension of the needle, thus to print geometries in micro and nano scale. E-jet printing process parameters can affect the final quality attributes of fabricated constructs. Currently, assessment of these critical geometries and attributes information must be performed offline using optical microscopy or scanning electron microscopy. This drawback affected the efficiency of micro/nano printing from translation to industrial practice. The research in this paper focused on fundamental research to enable in-situ monitoring of e-jet printing using a real-time images characterization technique. In conclusion, the study in this paper investigated using machine vision for real-time monitoring of micro/nano scale 3D printing. The method worked well for micro-filament detection in e-jet printing, and may be further implemented into feedback control system of complicated e-jet printing. However, the optical machine vision was limited to micro scale detection. One of the future research topic is to develop nano scale in-situ detection mechanism for e-jet printing.

As a part of the Argonne Strategic Partnership Project (SPP) 85E77, collaboration between Argonne National Laboratory (ANL) and Shanghai Institute of Applied Physics (SINAP), has produced designs for a precision compact flexure bending mechanism to provide elliptically shaped 90-mm and 160-mm long hard x-ray mirrors. The design utilizes Argonne’s laminar nanopositioning flexure technique. The flexure mirror bending mechanism will be incorporated into the beamline upgrade project at the Shanghai Synchrotron Radiation Facility (SSRF). Additionally, an Argonne Laboratory-Directed Research and Development (LDRD) project at the Advanced Photon Source (APS) has adopted a modified optomechanical design of the precision compact mirror benders for 300-mm-long hard x-ray mirrors with integrated profile monitoring and feedback, which are described in this paper. The mirror benders are designed with configurations for open-loop or closed-loop controls. Capacitive sensors can be applied to the mirror benders to ensure positioning reproducibility. Design specifications as well as finite element analyses results of the compact mirror benders for hard x-ray mirrors with trapezoid and rectangular shapes are discussed in this paper.

In the field of metal rolling, the quality of the steel roller’s surface is significant for the final rolling products, e.g. metal sheets or foils. Besides the dimensional accuracy and surface roughness, the optical uniformity of the roller surface is also required for high quality rolling application. The typical optical defects of rollers after finish grinding include speckles, chatter marks, feed traces, and combination of all above. Unlike surface roughness, the optical defects can hardly be characterized by the topography or scanning electrical microscope measurement. Only the inspection by bared eyes of experienced engineers appears to be the effective manner for surface optical defects examination for large steel rollers. In this paper, an on-site machine vision system is designed to add on to the roller grinding machine to capture the surface image, and then an improved optical defects segmentation algorithm is developed based on the active contour model. Finally, experiments are carried out to verify the efficacy of the improved model.In the field of metal rolling, the quality of the steel roller’s surface is significant for the final rolling products, e.g. metal sheets or foils. Besides the dimensional accuracy and surface roughness, the optical uniformity of the roller surface is also required for high quality rolling application. The typical optical defects of rollers after finish grinding include speckles, chatter marks, feed traces, and combination of all above. Unlike surface roughness, the optical defects can hardly be characterized by the topography or scanning electrical microscope measurement. Only the inspection by bared eyes of experienced engineers appears to be the effective manner for surface optical defects examination for large steel rollers. In this paper, an on-site machine vision system is designed to add on to the roller grinding machine to capture the surface image, and then an improved optical defects segmentation algorithm is developed based on the active contour model. Finally, experiments are carried out to ve...

To solve the problems in the DEM simulations of the screening process of a swing-bar sieve, in this paper we propose the real-virtual boundary method to build the geometrical model of the screen deck on a swing-bar sieve. The motion of the swing-bar sieve is modelled by the planer multi-body kinematics. A coupled model of the discrete element method (DEM) with multi-body kinematics (MBK) is presented to simulate the flowing and passing processes of soybean particles on the screen deck. By the comparison of the simulated results with the experimental results of the screening process of the LA-LK laboratory scale swing-bar sieve, the feasibility and validity of the real-virtual boundary method and the coupled DEM-MBK model we proposed in this paper can be verified. This work provides the basis for the optimization design of the swing-bar sieve with circular apertures and complex motion.

One of the solutions for improving quality of a railway pantograph-catenary contact during a high speed run is to implement an active control in the pantograph system. The goal of the control is to adjust an actual uplift force exerted by a pantograph on a contact line to reduce fluctuations observed in the reaction force course. While the closed-loop control is conducted, the actual contact force has to be measured. The paper presents a new design of the load cell dedicated for that purpose. The shape of the designed and manufactured device was chosen to allow for easy implementation in a pantograph construction. The load cell is based on the Fiber-Bragg grating sensor, since more popular techniques based on electric quantities measurements may be disturbed by strong electromagnetic field which is present in the vicinity of pantograph-catenary interface. The paper discusses the results of sensor validation procedure.

There is need to replace the traditional materials used in mechanical constructions with cheaper materials characterized by high durability and simplicity of manufacturing. An alternative technology is 3D printing technology that uses ABS material (poly (acrylonitrile-co-butadiene-co-styrene)). 3D printing technology ensures the rapid change of model dimensions and shapes at the prototyping stage and a relatively cheap cost of new elements. There are many plastic materials producers on the market for a 3D printer. In this paper two of them have been choosen to a comparison and their mechanical parameters have been determined. The modal analysis of this material was carried out and the obtained values of resonance frequencies were compared.There is need to replace the traditional materials used in mechanical constructions with cheaper materials characterized by high durability and simplicity of manufacturing. An alternative technology is 3D printing technology that uses ABS material (poly (acrylonitrile-co-butadiene-co-styrene)). 3D printing technology ensures the rapid change of model dimensions and shapes at the prototyping stage and a relatively cheap cost of new elements. There are many plastic materials producers on the market for a 3D printer. In this paper two of them have been choosen to a comparison and their mechanical parameters have been determined. The modal analysis of this material was carried out and the obtained values of resonance frequencies were compared.

This paper describes the aerodynamic design of the scaled air test rig of axial exhaust casing. The axial exhaust casings are used to benefit steam turbines of less than 180 MW, and their design can significantly affect the performance of the last stage and thus the performance of the entire steam turbine. The proposed test rig, along with extensive CFD simulations, will help to optimize the flowing in the exhaust casing and provide the ability to reliably predict losses in the exhaust casing on real steam turbines. Part of the study will be the detection of the influence of the individual components of the velocity at the diffuser inlet, the effect of the number, shape and arrangement of the internal struts. Last but not least, the effect of a wall jet blowing into the outer diffuser wall will be studied. The aerodynamic design of the test rig itself required a lot of numerical simulations to achieve the desired velocity profile at the diffuser inlet. It has been shown that it is difficult to simulate the radial component of the velocity in experimental conditions. The desired circumferential component of the velocity can be achieved more easily by suitable shaping of the stationary blade grid at the diffuser inlet.This paper describes the aerodynamic design of the scaled air test rig of axial exhaust casing. The axial exhaust casings are used to benefit steam turbines of less than 180 MW, and their design can significantly affect the performance of the last stage and thus the performance of the entire steam turbine. The proposed test rig, along with extensive CFD simulations, will help to optimize the flowing in the exhaust casing and provide the ability to reliably predict losses in the exhaust casing on real steam turbines. Part of the study will be the detection of the influence of the individual components of the velocity at the diffuser inlet, the effect of the number, shape and arrangement of the internal struts. Last but not least, the effect of a wall jet blowing into the outer diffuser wall will be studied. The aerodynamic design of the test rig itself required a lot of numerical simulations to achieve the desired velocity profile at the diffuser inlet. It has been shown that it is difficult to simulate th...

The Rim-driven Thruster (RDT) is a new type of marine electric thruster proposed in recent years. In this paper, the author proposed a new type of permanent magnet synchronous rim thrust motor (RTM). The motor uses a Halbach array permanent magnet rotor, which can improve the torque density of the propulsion motor by utilizing the unilateral magnetic field of the Halbach array. In this paper, the electromagnetic properties of the motor were measured and compared with that of the ordinary magnetic pole motor through numerical analysis. The results show that at the same power, the new motor can significantly reduce the thickness of the rotor’s permanent magnet and yoke core, and has obvious advantages in power density, moment of inertia, dynamic performance, and cost.

Nowadays, satellites have a short lifespan due to the limited quantity of propellant that can be taken on board. On the other hand, some of the used propellants are not environmentally friendly, some of them being considered even poisonous, as hydrazine. This paper presents a new design concept for an environmentally friendly satellite propulsion system where an advanced technology and materials are used. This propulsion system is presently in a research-design-manufacturing stage at the Romanian Research and Development Institute for Gas Turbines - COMOTI. To reduce the necessary propellant quantity, in the case of cold gas propulsion systems working with gaseous N2, the periodical heating of gas using concentrated solar light was considered. When the correction of satellite attitude is necessary, the cold N2 is sent from the main tank in a small service tank placed in the focal point of a gold plated composite parabolic mirror. The mirror is permanently oriented with the concave (reflective) surface to the Sun. The sun rays parallel with the mirror’s symmetry plane are focused by the parabolic mirror on the service tank placed in its focal point (line). In this way the temperature of N2 from the service tank increases quickly with several degrees Celsius and the reaction force increases when the gas is expanded in the Laval nozzles. The parabolic mirror is made of carbon fiber composite, thus making the structure very light, (around 0.5 kg). The Laval nozzles have extremely thin walls (0.5 mm) being made using a technology of wall stiffening with Cerrobend alloy during machining.Nowadays, satellites have a short lifespan due to the limited quantity of propellant that can be taken on board. On the other hand, some of the used propellants are not environmentally friendly, some of them being considered even poisonous, as hydrazine. This paper presents a new design concept for an environmentally friendly satellite propulsion system where an advanced technology and materials are used. This propulsion system is presently in a research-design-manufacturing stage at the Romanian Research and Development Institute for Gas Turbines - COMOTI. To reduce the necessary propellant quantity, in the case of cold gas propulsion systems working with gaseous N2, the periodical heating of gas using concentrated solar light was considered. When the correction of satellite attitude is necessary, the cold N2 is sent from the main tank in a small service tank placed in the focal point of a gold plated composite parabolic mirror. The mirror is permanently oriented with the concave (reflective) surface to ...

Additive Manufacturing (AM) processes offer the potential for manufacturing cost savings and rapid insertion into service through production of near net shape components for complicated structures. Use of these parts in high reliability applications such as those in the aerospace industry will require nondestructive characterization methods to ensure post-process material quality in as-built condition. Ultrasonic methods can be used for this quality verification. Depending on the application, the service life of AM components can be sensitive to the part surface condition. The surface roughness and layered structure inherent to the electron-beam powder-bed fusion process necessitates new approaches to evaluate subsurface material integrity in its presence. Experimental methods and data analytics may improve the evaluation of as-built additively manufactured materials. This paper discusses the assessment of additively manufactured EBM Ti-6Al-4V panels using ultrasonic methods and the data analytics applied to evaluate material integrity. The assessment was done as an exploratory study as the discontinuities of interest in these test samples were not known when the measurements were performed. Water immersion ultrasonic techniques, including pulse-echo and through transmission with 10 MHz focused transducers, were used to explore the material integrity of as-built plates. Subsequent destructive mechanical tests of specimens extracted from the plates provided fracture locations indicating critical flaws. To further understand the effect of surface-roughness, an evaluation of ultrasonic response in the presence of as-built surfaces and with the surface removed was performed. The assessment of additive manufactured EBM Ti-6Al-4V panels with ultrasonic techniques indicated that ultrasonic energy was attenuated by the as-built surface roughness. In addition, feature detection was shown to be sensitive to experimental ultrasonic parameters and flaw morphology.Additive Manufacturing (AM) processes offer the potential for manufacturing cost savings and rapid insertion into service through production of near net shape components for complicated structures. Use of these parts in high reliability applications such as those in the aerospace industry will require nondestructive characterization methods to ensure post-process material quality in as-built condition. Ultrasonic methods can be used for this quality verification. Depending on the application, the service life of AM components can be sensitive to the part surface condition. The surface roughness and layered structure inherent to the electron-beam powder-bed fusion process necessitates new approaches to evaluate subsurface material integrity in its presence. Experimental methods and data analytics may improve the evaluation of as-built additively manufactured materials. This paper discusses the assessment of additively manufactured EBM Ti-6Al-4V panels using ultrasonic methods and the data analytics applied...

As an important part of the valve opening and closing controller in engine, camshaft has high machining accuracy requirement in designing. Taking the high-speed camshaft grinder spindle system as the research object and the spindle system performance as the optimizing target, this paper firstly uses Solidworks to establish the three-dimensional finite element model (FEM) of spindle system, then conducts static analysis and the modal analysis by applying the established FEM in ANSYS Workbench, and finally uses the design optimization function of the ANSYS Workbench to optimize the structure parameter in the spindle system. The study results prove that the design of the spindle system fully meets the production requirements, and the performance of the optimized spindle system is promoted. Besides, this paper provides an analysis and optimization method for other grinder spindle systems.

The technology of parabolic trough collectors (PTC) is used widely in concentrating Solar Power (CSP) plants worldwide. However this type of large-size collectors cannot be officially tested by an accredited laboratory and certified by an accredited certification body so far, as there is no standard adapted to its particularity, and the current published standard for solar thermal collectors are not completely applicable to them. Recently some standardization committees have been working on this technology. This paper aims to give a summary of the standardized testing methodology of large-size PTC for CSP plants, giving the physical model chosen for modeling the thermal performance of the collector in the new revision of standard ISO 9806 and the points still to be improved in the standard draft IEC 62862-3-2. In this paper, a summary of the testing validation performed on one parabolic trough collector installed in one of the test facilities at the Plataforma Solar de Almeria (PSA) with this new model is also presented.

LS-type screw conveyor has been extensively used in the transportation of powder coal mine. Reasonable selection and design of the structure and parameters of conveyor body is the most significant for the transportation of powder coal mine. The whole structure and the working principle of the LS-type screw conveyor were introduced in the paper. And then the design and calculation formula of key components on LS-type spiral conveyor body, such as screw shaft, spiral blade and intermediate bearing are given. This paper makes a further research on design of key components on LS-type spiral conveyor, providing theoretical basis for the application of the screw conveyor in powder coal mine.

This paper proposes the design of liner type hydraulic motor on the base of inner curved radial piston hydraulic motor. The hydraulic cylinders of the new type motor are in the straight line which will improve the utilization of the axial space and different out power can be supplied by changes the number of cylinders. In this paper, the structure and working principle of the liner type hydraulic motor is introduced.

Traditional rake type mulching film recycling machine has the problem of difficulty in unloading and packing film, poor continuity of the work. In order to solve such problems, this paper designs a kind of chain rake type mulching film recycling machine which can realize continuous raking film, collecting film, transporting film, shaking off soil, unloading film. Rake teeth is the basic part of chain rake mulching recycling machine. The stability of rake teeth’s inserting soil is an important factor to ensure recovery efficiency of the plastic film recovery. By virtual prototype simulation, this paper study the influence of different factors on the stability of rake teeth inserting soil. The results are as follow: ①The speed of chain rake has no significant effect on the stability of rake teeth inserting soil; ②Reducing resistance of rake teeth in the process of working, is conducive to improve the stability of rake teeth inserting soil; ③Appropriate increasing elastic modulus of chain rake, is helpful to...

This paper reviews the literature on the response of polymers to high strain rate deformation. The main focus is on the experimental techniques used to characterize this response. The paper includes a small number of examples as well as references to experimental data over a wide range of rates, which illustrate the key features of rate dependence in these materials; however this is by no means an exhaustive list. The aim of the paper is to give the reader unfamiliar with the subject an overview of the techniques available with sufficient references from which further information can be obtained. In addition to the ‘well established’ techniques of the Hopkinson bar, Taylor Impact and Transverse impact, a discussion of the use of time-temperature superposition in interpreting and experimentally replicating high rate response is given, as is a description of new techniques in which mechanical parameters are derived by directly measuring wave propagation in specimens; these are particularly appropriate for polymers with low wave speeds. The vast topic of constitutive modelling is deliberately excluded from this review.

This paper aims to study the effect of the thermoforming process on the assembly of a newly developed stretchable material for electric circuit and LEDs for manufacturing of automotive lighting. The thermoforming process was conducted using a mould developed based on commercially available automotive lighting product. The circuit was initially printed on a flat thermoplastic substrate using screen printing technique prior to the thermoforming process. The quality of the product was investigated before and after thermoforming process through quantitative measurement and visual inspection in terms of the circuit’s resistivity and the electrical conductivity, respectively. The resistivity measurement was conducted by using four point probes instrument to compare the resistivity of the circuit which depends on stretch level of circuit and substrate during the thermoforming process. The stretch level was found to be different along the geometry due to the unsymmetrical geometry of the mould. The electrical conductivity of the circuit was also tested by LEDs illumination through power supply connection. This study shows promising results in applying thermoforming process in the fabrication of 3-dimensional shape product with lower cost equipment.This paper aims to study the effect of the thermoforming process on the assembly of a newly developed stretchable material for electric circuit and LEDs for manufacturing of automotive lighting. The thermoforming process was conducted using a mould developed based on commercially available automotive lighting product. The circuit was initially printed on a flat thermoplastic substrate using screen printing technique prior to the thermoforming process. The quality of the product was investigated before and after thermoforming process through quantitative measurement and visual inspection in terms of the circuit’s resistivity and the electrical conductivity, respectively. The resistivity measurement was conducted by using four point probes instrument to compare the resistivity of the circuit which depends on stretch level of circuit and substrate during the thermoforming process. The stretch level was found to be different along the geometry due to the unsymmetrical geometry of the mould. The electrical con...

Dynamically induced phase transitions in metals, within the present discussion, are those that take place within a time scale characteristic of the shock waves and any reflections or rarefactions involved in the loading structure along with associated plastic flow. Contemporary topics of interest include the influence of loading wave shape, the effect of shear produced by directionality of the loading relative to the sample dimensions and initial velocity field, and the loading duration (kinetic effects, hysteresis) on the appearance and longevity of a transformed phase. These topics often arise while considering the loading of parts of various shapes with high explosives, are typically two or three-dimensional, and are often selected because of the potential of the transformed phase to significantly modify the motion. In this paper, we look at current work on phase transitions in metals influenced by shear reported in the literature, and relate recent work conducted at Los Alamos on iron’s epsilon phase transition that indicates a significant response to shear produced by reflected elastic waves. A brief discussion of criteria for the occurrence of stress induced phase transitions is provided. Closing remarks regard certain physical processes, such as fragmentation and jet formation, which may be strongly influenced by phase transitions.Dynamically induced phase transitions in metals, within the present discussion, are those that take place within a time scale characteristic of the shock waves and any reflections or rarefactions involved in the loading structure along with associated plastic flow. Contemporary topics of interest include the influence of loading wave shape, the effect of shear produced by directionality of the loading relative to the sample dimensions and initial velocity field, and the loading duration (kinetic effects, hysteresis) on the appearance and longevity of a transformed phase. These topics often arise while considering the loading of parts of various shapes with high explosives, are typically two or three-dimensional, and are often selected because of the potential of the transformed phase to significantly modify the motion. In this paper, we look at current work on phase transitions in metals influenced by shear reported in the literature, and relate recent work conducted at Los Alamos on iron’s epsilon phase ...

The paper presents a vertical U-tube steam generator mathematical model which is developed in MATLAB environment. In the model is used single phase or humongous fluid and are made some simplifications in order to save computational time. After the model was build several numerical simulations were conducted. The changes of some main parameter values like primary water temperature, metal tube temperature, steam generator pressure, and so on are presented in graphs and tables.The paper presents a vertical U-tube steam generator mathematical model which is developed in MATLAB environment. In the model is used single phase or humongous fluid and are made some simplifications in order to save computational time. After the model was build several numerical simulations were conducted. The changes of some main parameter values like primary water temperature, metal tube temperature, steam generator pressure, and so on are presented in graphs and tables.

The paper presents preliminary results of dynamic tests of the masonry barrel vault in a technical scale. Experimental studies are intended to identify material properties of homogenized masonry vaults under dynamic loads. The aim of the work is to create numerical models to analyse vault’s dynamic response to dynamic loads in a simplest and accurate way. The process of building the vault in a technical scale is presented in the paper. Furthermore a excitation of vibrations with an electrodynamic modal exciter placed on the vault, controlled by an arbitrary waveform function generator, is discussed. Finally paper presents trends in the research for homogenization algorithm enabling dynamic analysis of masonry vaults.Experimental results were compared with outcomes of so-called macromodels (macromodel of a brick masonry is a model in which masonry, i.e. a medium consisting of two different fractions – bricks and mortar, is represented by a homogenized, uniformed, material). Homogenization entail significan...

Eddy current transducers (ECT) are used to construct a sensor for investigating titanium sheets connected by a welded joint. The paper provides key technical information about the eddy current transducer used and describes the procedure of measurements that makes it possible to control defects in welded joints of titanium alloys. It is capable of automatically changing the filtering cutoff frequency and operating frequency of the device. Experiments were conducted on welded VT1-0 titanium plates. The paper contains the results of these measurements. The dependence data facilitates the assessment of the quality of the welded joints and helps make an educated conclusion about welding quality.

This paper researched experiment results and analysis of ceramic insert turning nickel-based HSTR Inconel 718. According to the curves and pictures, discuss the relationship of cutting parameters and cutting force and the factors. This paper also researched tool failure by insert picture and sought the reasons for it.

The paper deals with use of LOOP thermosyphon heat pipe to transfer heat from electrotechnical box and describe of construction individual types of LOOP heat pipes. The LOOP heat pipe is very good cooling device which requires no mechanical parts in their design. LOOP heat pipe use only phase change during heat transfer, without a compressor, fan or pump. LOOP heat pipe is more energy saving compared to conventional cooling systems with forced convection. The main advantage of cooling by heat pipe is that electrotechnical box can be hermetically closed (dust -free construction), because dust reduces the lifetime of electrotechnical elements in box. Lifetime of LOOP heat pipe equals to the lifetime of construction material. The paper describes mathematical model of LOOP thermosyphon heat pipe (condenser). Compares selected types of working fluids which are filled with a heat pipe and construction materials of heat pipe.

A new type of power plant. i.e, Electric Power Confined Piston Engine, is invented by combining the free piston engine and the crank connecting rod mechanism of the traditional internal combustion engine. Directly using the reciprocating movement of the piston, this new engine converts the heat energy produced by fuel to electrical energy and output it. The paper expounds the working mechanism of ECPE and establishes the kinematics and dynamics equations. Furthermore, by using the analytic method, the ECPE electromagnetic force is solved at load cases. Finally, in the simulation environment of MARLAB, the universal characteristic curve is obtained in the condition of rotational speed n between 1000 r/min and 2400 r/min, throttle opening α between 30% and 100%.A new type of power plant. i.e, Electric Power Confined Piston Engine, is invented by combining the free piston engine and the crank connecting rod mechanism of the traditional internal combustion engine. Directly using the reciprocating movement of the piston, this new engine converts the heat energy produced by fuel to electrical energy and output it. The paper expounds the working mechanism of ECPE and establishes the kinematics and dynamics equations. Furthermore, by using the analytic method, the ECPE electromagnetic force is solved at load cases. Finally, in the simulation environment of MARLAB, the universal characteristic curve is obtained in the condition of rotational speed n between 1000 r/min and 2400 r/min, throttle opening α between 30% and 100%.

According to available literature, it is assumed that outer packaging container, which is usually made of corrugated cardboard, does not influence the mitigation of the impact effects, thus in the designing process of packaging system the outer packaging is skipped. The purpose of this paper is to verify the above assumption, including determination of the influence of the 5-layer cardboard on the properties of structures that consist of that cardboard and polyethylene foam. Verification is performed with the use of the finite element method. To apply this method the dynamic compression curve of cushioning material is required. Therefore in the paper it is also presented the modified method to determine the curve.

Alstom is developing solar power tower plants utilizing molten salt as the working fluid. In solar power tower, the molten salt central receiver (MSCR) atop of the tower is constructed of banks of tubes arranged in panels creating a heat transfer surface exposed to the solar irradiation from the heliostat field. The molten salt heat transfer fluid (HTF), in this case 60/40%wt NaNO3-KNO3, flows in serpentine flow through the surface collecting sensible heat thus raising the HTF temperature from 290°C to 565°C. The hot molten salt is stored and dispatched to produce superheated steam in a steam generator, which in turn produces electricity in the steam turbine generator. The MSCR based power plant with a thermal energy storage system (TESS) is a fully dispatchable renewable power plant with a number of opportunities for operational and economic optimization.This paper presents operation and controls challenges to the MSCR and the overall power plant, and the use of dynamic model computer simulation based transient analyses applied to molten salt based solar thermal power plant. This study presents the evaluation of the current MSCR design, using a dynamic model, with emphasis on severe events affecting critical process response, such as MS temperature deviations, and recommend MSCR control design improvements based on the results. Cloud events are the scope of the transient analysis presented in this paper. The paper presents results from a comparative study to examine impacts or effects on key process variables related to controls and operation of the MSCR plant.

This paper seeks to determine whether the Finite Volume method within a commercially available Computational Fluid Dynamics (CFD) solver (ANSYS Fluent) can model radiation with comparable accuracy to a Monte Carlo ray-tracing software package (SolTrace). A detailed investigation was performed into modeling techniques that can be used to significantly reduce the optical errors traditionally associated with CFD modeling of radiation false scattering and ray effect using a simple optical test case. The strategies formulated in the first part of this paper were used to model a variety of Linear Fresnel Collector Concentrating Solar Power Plants. This paper shows that commercial CFD packages yield accurate results for line focusing concentrating solar applications and simple geometries, validating its use in an integrated environment where both optical and thermal performance of these plants can be simulated and optimized.

Beamline commissioning activities at the Sub-micron Resolution Spectroscopy Beamline, SRX, one of the project beamlines of the National Synchrotron Light Source II, began in December 2014. SRX is a hard x-ray micro-probe beamline. The technical capabilities presented in this paper include scanning micro-fluorescence microscopy (µ-XRF) and x-ray absorption near-edge structure (µ-XANES) spectroscopy. The high flux KBs station with sub-micron resolution in the step-scanning mode has been commissioned with results presented in this paper. Capabilities under commissioning/planning include XRF-XANES stack imaging, a high resolution station (sub-100 nm), x-ray fluorescence tomography, integration of Maia detector, and fly-scan mode. Early science commissioning results from SRX in the materials science field are presented in this paper. Topics being studied include nanoporous materials for energy conversion/storage, thin film materials for electronics, degradation of paint materials for art conservation, and grain boundary segregation in structural materials. On December 7th 2015, SRX officially became a user-operational beamline and started accepting general users. The users of interest are encouraged to contact the beamline staff and submit General User Proposals.

The paper presents preliminary results of a partnership project between academic research groups and industrial partners. The LFR500 project aims at developing a prototype of Linear Fresnel Reflector (LFR) solar power plants able to work above 500°C providing Direct Steam Generation (DSG) under 90 bars. LFR plants usually operate at 300°C, but at 500°C the efficiency is raised by more than 50%. Since thermal losses are mainly radiative at this working temperature, the absorber layers must satisfy both conditions of solar absorption and low thermal emittance in the infrared (IR) domain (beyond 2450nm…). The paper will present both modeling, design of the absorptive multilayer and experimental demonstration of an absorbing tube at industrial scale. Furthermore, characterization and aging testing will be considered and presented

This paper presents a summary of the testing procedure and a validation of the methodology of parabolic trough collector in solar thermal power plants. The applied testing methodology is the one proposed within the Spanish standardization sub-committee AEN/CTN 206/SC117 working group WG2 related to the components for solar thermal power plants. This methodology is also proposed within the international committee IEC TC 117 (Standard draft IEC 62862-3-2 Ed. 1.0). This study is done at Plataforma Solar de Almeria (PSA) in Almeria within the European project STAGE-STE. This paper presents the results of the optical and thermal efficiency of a large-size parabolic trough collector. The obtained values are similar to the previous analysis on this collector by PSA. The results of the tracking system have a good accuracy compared to the acceptance angle of the concentrator.

This paper describes a new modular laboratory-scale experimental facility that was designed to conduct detailed aerothermal characterizations of volumetric absorbers for use in concentrating solar power plants. Absorbers are generally considered to be the element with the highest potential for efficiency gains in solar thermal energy systems. The configu-ration of volumetric absorbers enables concentrated solar radiation to penetrate deep into their solid structure, where it is progressively absorbed, prior to being transferred by convection to a working fluid flowing through the structure. Current design trends towards higher absorber outlet temperatures have led to the use of complex intricate geometries in novel ceramic and metallic elements to maximize the temperature deep inside the structure (thus reducing thermal emission losses at the front surface and increasing efficiency). Although numerical models simulate the conjugate heat transfer mechanisms along volumetric absorbers, they lack, in many cases, the accuracy that is required for precise aerothermal validations. The present work aims to aid this objective by the design, development, commissioning and operation of a new experimental facility which consists of a 7 kWe (1.2 kWth) high flux solar simulator, a radiation homogenizer, inlet and outlet collector modules and a working section that can accommodate volumetric absorbers up to 80 mm × 80 mm in cross-sectional area. Experimental measurements conducted in the facility include absorber solid temperature distributions along its depth, inlet and outlet air temperatures, air mass flow rate and pressure drop, incident radiative heat flux, and overall thermal efficiency. In addition, two windows allow for the direct visualization of the front and rear absorber surfaces, thus enabling full-coverage surface temperature measurements by thermal imaging cameras. This paper presents the results from the aerothermal characterization of a siliconized silicon carbide monolithic honeycomb, conducted at realistic conditions of incident radiative power per unit mass flow rate in order to validate its operation.

This paper discusses technological and construction ways to achieve a high working temperature with a high displacement in linear piezo motors. The first part reviews the results of the piezoelectric material development, its temperature stability testing and basic parameters for piezo motors. The second part focuses on the multilayer structure of piezoelectric elements, which are based on high-temperature piezoelectric materials (HTPM). Also analyzed are working temperatures of multilayer piezoelectric elements (MPE) and their hysteresis. Finally, the third part shows a comparison of three recent prototypes of high-temperature MPEs that were in our lab using different materials.This paper discusses technological and construction ways to achieve a high working temperature with a high displacement in linear piezo motors. The first part reviews the results of the piezoelectric material development, its temperature stability testing and basic parameters for piezo motors. The second part focuses on the multilayer structure of piezoelectric elements, which are based on high-temperature piezoelectric materials (HTPM). Also analyzed are working temperatures of multilayer piezoelectric elements (MPE) and their hysteresis. Finally, the third part shows a comparison of three recent prototypes of high-temperature MPEs that were in our lab using different materials.

Concentrating solar power co-generation systems have been identified as potential stand-alone solar energy supply solutions in remote rural energy applications. This study describes the modelling and synthesis of a combined heat and power Stirling CSP system in order to evaluate its potential performance in small off-grid rural village applications in Africa. This Stirling micro-Combined Heat and Power (micro-CHP) system has a 1 kW electric capacity, with 3 kW of thermal generation capacity which is produced as waste heat recovered from the solar power generation process. As part of the development of an intelligent microgrid control and distribution solution, the Trinum micro-CHP system and other co-generation systems are systematically being modelled on the TRNSYS simulation platform. This paper describes the modelling and simulation of the Trinum micro-CHP configuration on TRNSYS as part of the process to develop the control automation solution for the smart rural microgrid in which the Trinum will serve as a solar powerpack. The results present simulated performance outputs for the Trinum micro-CHP system for a number of remote rural locations in Africa computed from real-time TRNSYS solar irradiation and weather data (yearly, monthly, daily) for the relevant locations. The focus of this paper is on the parametric modelling of the Trinum Stirling micro-CHP system, with specific reference to this system as a TRNSYS functional block in the microgrid simulation. The model is used to forecast the solar energy harvesting potential of the Trinum micro-CHP unit at a number of remote rural sites in Africa.

Jet pumps are widely used in thermoacoustic Stirling heat engines and pulse tube cryocoolers to eliminate the effect of Gedeon streaming. The resistance properties of jet pumps are principally influenced by their structures and flow regimes which are always characterized by Reynolds numbers. In this paper, the jet pump of which cross section contracts abruptly is selected as our research subject. Based on linear thermoacoustic theory, a CFD model is built and the oscillating flow of the working gas is simulated and analyzed with different Reynolds numbers in the jet pump. According to the calculations, the influence of different structures and Reynolds numbers on the resistance properties of the jet pump are analyzed and presented. The results show that Reynolds numbers have a great influence on the resistance properties of jet pumps and some empirical formulas which are widely used are unsuitable for oscillating flow with small Reynolds numbers. This paper provides a more comprehensive understanding on resistance properties of jet pumps with oscillating flow and is significant for the design of jet pumps in practical thermoacoustic engines and refrigerators.

Liquefied hydrogen is presently mainly used for space applications and the semiconductor industry. While clean energy applications, for e.g. the automotive sector, currently contribute to this demand with a small share only, their demand may see a significant boost in the next years with the need for large scale liquefaction plants exceeding the current plant sizes by far. Hydrogen liquefaction for small scale plants with a maximum capacity of 3 tons per day (tpd) is accomplished with a Brayton refrigeration cycle using helium as refrigerant. This technology is characterized by low investment costs but lower process efficiency and hence higher operating costs. For larger plants, a hydrogen Claude cycle is used, characterized by higher investment but lower operating costs. However, liquefaction plants meeting the potentially high demand in the clean energy sector will need further optimization with regard to energy efficiency and hence operating costs. The present paper gives an overview of the currently applied technologies, including their thermodynamic and technical background. Areas of improvement are identified to derive process concepts for future large scale hydrogen liquefaction plants meeting the needs of clean energy applications with optimized energy efficiency and hence minimized operating costs. Compared to studies in this field, this paper focuses on application of new technology and innovative concepts which are either readily available or will require short qualification procedures. They will hence allow implementation in plants in the close future.

Applications in superconductivity have become widespread, enabled by advancements in cryogenic engineering. In this paper, the history of cryogenic refrigeration, its delivery, its preservation and the important scientific and engineering advancements in these areas in the last 100 years will be reviewed, beginning with small laboratory dewars to very large scale systems. The key technological advancements in these areas that enabled the development of superconducting applications at temperatures from 4 to 77 K are identified. Included are advancements in the components used up to the present state-of-the-art in refrigeration systems design. Viewpoints as both an equipment supplier and the end-user with regard to the equipment design and operations will be presented. Some of the present and future challenges in these areas will be outlined. Most of the materials in this paper are a collection of the historical materials applicable to these areas of interest.

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Electrostatic storage rings have proven to be invaluable tools for atomic and molecular physics at the ultra‐low energy range from 1 to 100 keV/A. Due to the mass independence of the electrostatic rigidity these machines are able to store a wide range of different particles, from light ions to heavy singly charged bio‐molecules. Their beam dynamics is, however, fundamentally different to magnetic storage rings and therefore needs to be investigated in detail to optimize storage ring performance and experimental output. This paper first gives an overview of existing electrostatic storage rings and their experimental programs. Second, future machines in Heidelberg, Stockholm and the Facility for Antiproton and Ion Research (FAIR) are described and the main challenges are summarized. Finally, the focus is set on a flexible storage ring facility presently being built up at the King Abdulaziz Center for Science and Technology (KACST) in Riyadh, Saudi Arabia, that addresses a broad user community and will allow for a next‐generation experimental program in the low energy regime.Electrostatic storage rings have proven to be invaluable tools for atomic and molecular physics at the ultra‐low energy range from 1 to 100 keV/A. Due to the mass independence of the electrostatic rigidity these machines are able to store a wide range of different particles, from light ions to heavy singly charged bio‐molecules. Their beam dynamics is, however, fundamentally different to magnetic storage rings and therefore needs to be investigated in detail to optimize storage ring performance and experimental output. This paper first gives an overview of existing electrostatic storage rings and their experimental programs. Second, future machines in Heidelberg, Stockholm and the Facility for Antiproton and Ion Research (FAIR) are described and the main challenges are summarized. Finally, the focus is set on a flexible storage ring facility presently being built up at the King Abdulaziz Center for Science and Technology (KACST) in Riyadh, Saudi Arabia, that addresses a broad user community and will allow...

This paper presents the results of a data collection effort, allowing to assess the overall environmental impact of the air bending process using the CO2PE!-Methodology. First the different modes of the air bending process are investigated, including both productive and non-productive modes. In particular consumption of electric power is recorded for the different modes. Subsequently, time studies allow determining the importance of productive and non-productive modes of the involved process. The study demonstrates that the influence of standby losses can be substantial. In addition to life cycle analysis, in depth process analysis also provides insight in achievable environmental impact reducing measures towards machine tool builders and eco-design recommendations for product developers. The energy consumption of three different machine tool architectures are analysed and compared within this paper. ispartof: pages:1650-1655 ispartof: AIP Conf. Proc. vol:1353 issue:1 pages:1650-1655 ispartof: ESAFORM2011 location:Belfast date:27 Apr - 29 Apr 2011 status: published

A two‐stage long‐life, low mass and efficient pulse tube cooler for space applications has been developed and acceptance tested for flight applications.This paper presents the data collected on four flight coolers during acceptance testing. Flight acceptance test of these cryocoolers includes thermal performance mapping over a range of reject temperatures, launch vibration testing and thermal cycling testing. Designed conservatively for a 10‐year life, the coolers are required to provide simultaneous cooling powers at 95 K and 180 K while rejecting to 300 K with less than 187 W input power to the electronics. The total mass of each cooler and electronics system is 8.7 kg. The radiation‐hardened and software driven control electronics provides cooler control functions which are fully re‐configurable in orbit. These functions include precision temperature control to better than 100 mK p‐p. This 2 stage cooler has heritage to the 12 Northrop Grumman Aerospace Systems (NGAS) coolers currently on orbit with 2 operating for more than 11.5 years.A two‐stage long‐life, low mass and efficient pulse tube cooler for space applications has been developed and acceptance tested for flight applications.This paper presents the data collected on four flight coolers during acceptance testing. Flight acceptance test of these cryocoolers includes thermal performance mapping over a range of reject temperatures, launch vibration testing and thermal cycling testing. Designed conservatively for a 10‐year life, the coolers are required to provide simultaneous cooling powers at 95 K and 180 K while rejecting to 300 K with less than 187 W input power to the electronics. The total mass of each cooler and electronics system is 8.7 kg. The radiation‐hardened and software driven control electronics provides cooler control functions which are fully re‐configurable in orbit. These functions include precision temperature control to better than 100 mK p‐p. This 2 stage cooler has heritage to the 12 Northrop Grumman Aerospace Systems (NGAS) coolers currently on orbit with 2 ...

Two liquefaction cycles for LNG (liquefied natural gas) production are compared in this paper. One is a well known MR (mixed refrigerant) JT cycle with two phase separators and four heat exchangers. Another one is the novel concept of hybrid cycle, which is to replace the last stage JT expansion with a turbine expander. The inlet flow to the turbine expander is deliberately warmed up by NG (natural gas) stream to guarantee superheated vapor phase and increase useful work. The turbine expander is to extract pressure exergy and reduce entropy generation by producing work and alleviating work requirement in the compressor. This paper describes the detailed processes of hybrid JT‐expander cycle and the quantitative comparison results by HYSYS simulation under some realistic physical constraints.

A novel heat transfer loop for thermoacoustic‐Stirling engines which could substitute for a traditional heat exchanger was developed. This new heat transfer loop uses a pair of check valves to transform oscillating flow into steady flow that allows the oscillating flow system’s own working gas to go through a physically remote high‐temperature or cold‐temperature heat source. Since the early principle experiment has achieved success, this paper explores the real operating performance of this heat transfer loop by coupling with thermoacoustic‐Stirling engine. Furthermore, a new type water‐cooled heat exchanger was developed in this paper to deduce the extra acoustic power dissipation. In addition, the influence of two kinds of check valves the heat transfer loop was discussed in this paper. The loop with 0.1 mm valve disc thickness shows that the heat transfer capacity is higher than the traditional heat exchanger. Our experiments have demonstrated its feasibility and flexibility for practical applications.

This paper presents the use of a commercial CFD code to simulate the flow‐field within the regenerative pump and compare the CFD results with new experimental data. Regenerative pumps are the subject of increased interest in industry as these pumps are low cost, low specific speed, compact and able to deliver high heads with stable performance characteristics. The complex flow‐field within the regenerative pump represents a considerable challenge to detailed mathematical modelling. This paper also presents a novel rapid manufacturing process used to consider the effect of impeller geometry changes on the pump efficiency. Ten modified impeller blade profiles, relative to a standard radial configuration, were evaluated. The CFD performance results demonstrate reasonable agreement with the experimental tests. The CFD results also demonstrate that it is possible to represent the helical flow field for the pump which has only been witnessed in experimental flow visualisation until now. The ability to use CFD modelling in conjunction with rapid manufacturing techniques has meant that more complex impeller geometry configurations can now be assessed with better understanding of the flow‐field and resulting efficiency.