Large-scale accelerator alignment using an inclinometer

A precise inclinometer (Talyvel 4) was adopted for evaluating aligning straightness of the first 71 m of the KEK electron/positron injector linear accelerator (linac). The straightness could be evaluated with a standard deviation of less than 49 μm. It is in good agreement with those obtained using a conventional alignment telescope and our laser-based alignment system.Error estimation based on the rules of error propagation shows that shape evaluation with a standard deviation of 0.3 mm for a distance of 500 m can be achieved using the proposed method. It indicates that this method is suitable for evaluating straightness of several hundred meters of linacs with sub-millimeter of accuracy.     

Straightness evaluation using inclinometers with a pair of offset bars

To evaluate the straightness of large objects, the use of an inclinometer is advantageous because it requires neither straight shape references nor transferring mechanisms. Herein, we consider adopting it for precise (with greater accuracy than 1 mm) evaluation of the straightness of linear particle accelerators (linacs) that are several hundred meters long or longer. In this study, the straightness evaluation of a 206-m-long part of the KEK injector linac was demonstrated using inclinometers with a pair of cantilevers called offset bars. The offset bars were adopted to extend the evaluation length by avoiding obstacles that block the evaluation path. Errors caused by the offset bars can be eliminated by reversal measurement considering the slope angles of the offset bars. The derived straightness corresponded with those derived by an alignment telescope and a laser-based alignment system within several millimeters and partly within several hundred micrometers. The reproducibility of slope angles for an arbitrary measurement point was 15 μrad at standard deviation. This corresponds to a standard deviation of 0.47 mm for straightness, with a total evaluation length of 500 m and measurement intervals of 2 m. The results indicate that our newly devised method is applicable for evaluating the straightness.     

Evolution of wear,roughness, and friction of Alloy 600 superalloy surfaces in water-submersed sliding

Self-mated wear and friction of Alloy 600 superalloy was studied in a water-submersed ring-on-rod configuration, loading the side of a 6.35 mm diameter rod across the flat surface of a rotating annular ring of 100 mm outer diameter and 70 mm inner diameter producing two sliding contacts along the ring. Tests were conducted at sliding speeds of 0.178 and 0.330 m/s for sliding distances of 100 m. Normal loads of 51 and 204 N were applied, and initial R_a surface roughnesses of the rings along the sliding direction were either smooth (～0.2 μm) or rough (～7.5 μm). Increased initial ring roughness caused a ～20-fold increase in rod wear at the lighter load, whereas at the heavier load increased initial roughness only caused a ～4-fold increase in wear. At lower initial ring roughness the 4-fold decrease in normal load caused a large (one order-of-magnitude) decrease in rod wear, whereas for rings of higher initial roughness the 4-fold decrease in normal load caused only minor (2-fold or less) decreases in rod wear. Wear during this 100 m sliding distance only experienced a minor effect from the 1.8-fold change in sliding speed, as did friction. In all cases friction coefficient rapidly settled into the range 0.6–0.7, except in the cases of lower load on rings of lower initial roughness where friction coefficient remained above 1 for most of this sliding duration. At this lower load the initial ～0.2 μm rod roughnesses increased to nearly 0.8 μm by the 100 m sliding distance, whereas at the higher load this same sliding distance resulted in roughnesses returning near to the initial 0.2 μm. It was hypothesized more highly loaded cases also went through initial roughening prior to smoothening back to 0.2 μm roughness within the 100 m sliding distance, and given additional sliding the more lightly loaded cases would also experience subsequent smoothening. Increasing sliding distance to 400 m, roughnesses indicated a smoothening back to 0.2 μm level during those lightly loaded tests, with friction coefficient correspondingly dropping from 1 into the 0.6–0.7 range observed in all other cases. Extended sliding to 400 m at light loading against rings of lower initial roughness also allowed a rod wear rate which increased with increased sliding distance to be observed, approaching the same rate observed against initially rough rings within the 100 m sliding distance.     

High precision self-alignment using liquid surface tension for additively manufactured micro components

Self-assembly of components using liquid surface tension is an attractive alternative to traditional robotic pick-and-place as it offers high assembly accuracy for coarse initial part placement. One of the key requirements of this method is the containment of the liquid within a designated binding site. This paper looks to expand the applications of self-assembly and investigates the use of topographical structures applied to 3D printed micro components for self-assembly using liquid surface tension. An analysis of the effect of edge geometry on liquid contact angle was conducted. A range of binding sites were produced with varying edge geometries, 45–135°, and for a variety of site shapes and sizes, 0.4–1 mm in diameter, and 0.5 mm × 0.5 mm–1 mm × 1 mm square. Liquid water droplets were applied to the structures and contact angles measured. Significant increases in contact angle were observed, up to 158°, compared to 70° for droplets on planar surfaces, demonstrating the ability of these binding sites to successfully pin the triple contact line at the boundary. Three challenging self-assembly cases were examined: (1) linear initial component misplacement >0.5 mm, (2) angular misplacement of components, and (3) misplacement of droplet. Across all three assembly cases the lowest misalignments in final component position, as well as highest repeatability, were observed for structures with actual edge geometries <90° (excluding 45° nominal), where the mean magnitude of misalignment was found to be 31 μm with 14 μm standard deviation.     

Analysis of tunnel displacement accuracy with total station

The remote distance measurement (RDM) method requires only common total stations and not special post-processing software. Moreover, this method is easy to operate and highly accurate results can be obtained. Therefore, RDM is used in the displacement monitoring of tunnel engineering. This study presents the calculation formulas for the crown settlement and wall convergence of tunnel as measured by RDM with total station. The mean error formulas are derived based on error propagation laws. When tunnel displacements measured by using total station with the m_s not more than 2 mm + 2D ppm (D is the measurement distance) and m_α not more than 1″, the horizontal distance between the rear viewpoint and the monitoring section is in the range of 50–150 m, the horizontal distance between the total station and the monitoring section ranges from 40 m to 60 m, and the total station is near the tunnel centerline, the measurement accuracy can reach 1 mm.     

Surface roughness measurement based on fiber optic sensor

The multi-wavelength fiber sensor for measuring surface roughness and surface scattering characteristics were investigated. In this paper, specimens with different surface roughness were analyzed by using 650 nm, 1310 nm and 1550 nm laser as the light source, respectively. The working distance of 2 mm was chosen as the optimum measurement distance. The experimental results indicate that multi-wavelength fiber sensor can accurately measure surface roughness, and can effectively reduce the unsystematic error. The light scattering intensity ratio has a good linear relationship with the surface roughness. The minimum relative error of the surface roughness is 2.92%, the maximum relative error is 13.4%, and the average relative error is about 7.48%. The accuracy for measuring surface roughness by multi-wavelength fiber sensor is about twice as large as that by single-wavelength fiber sensor.     

Micro-rotary ratchets driven by migratory phytoplankton with phototactic stimulus

This study proposes micro-rotary ratchets driven by a migratory phytoplankton–Volvox, exhibiting a positive phototaxis. Two types of micro-discs, i.e., ratchet- and starfish-like ratchets are fabricated using conventional photolithography. The ratchet is floated in the center of a Petri dish filled with Volvox suspension under an optical microscope with halogen lamp illumination and is covered by a mask with a small hole so that the microorganisms are concentrated around the micro-ratchets by the phototaxis. Rotations of the ratchets with the same diameter of 0.567 mm were observed through a biological microscope; a rotation speed of 0.86 rpm for the micro-ratchet and 2.01 rpm for the starfish ratchet were obtained for a Volvox density of 1000–3000/mL under an illumination intensity of 0.18 W/cm². As the driving mechanism of the ratchet is based on the microorganisms adhesion to the ratchets surface rather than collision impacts, a gelatin coating on the ratchet was used to enhance the adhered number of Volvox. Although the drag force was increased owing to the larger ratchet diameter, a rotation speed of 0.16 rpm was observed. A particle tracking velocimetry measurement using polystyrene beads was performed to study the fluid flow around the micro-ratchet. A vortex generation by the micro-ratchets was confirmed; this effect may work as a micro-mechanical power booster for microorganisms. This drive system may open the possibility of a solar-power-driven and sustainable micro-mechanism using phytoplankton.     

Simultaneous distributed measurement of the strain and temperature for a four-point bending test using polarization-maintaining fiber Bragg grating interrogated by optical frequency domain reflectometry

We demonstrate a simultaneous distributed strain and temperature measurement technique with the spatial resolution of 1 mm using fiber Bragg gratings inscribed in a polarization-maintaining and absorption-reducing fiber (PANDA-FBGs) and optical frequency domain reflectometry (OFDR). We conduct four-point bending tests in an environmental chamber. Using high birefringent PANDA-FBGs that are manufactured specifically for the simultaneous measurements, the uniform temperature distributions and the typical strain distribution profiles of the four-point bending tests were successfully obtained. The measurement errors of strain were from −31 με to 19 με, and of temperature were from −0.9 °C to 1.3 °C. The spatial standard deviation was 7.5 με and 0.9 °C. We also discussed the effect of the residual strain of the sensor-bonding procedures and the data averaging.     

Performance tests of a new non-invasive sensor unit and ultrasound electronics

Industrial applications involving pulsed ultrasound instrumentation require complete non-invasive setups due to high temperatures, pressures and possible abrasive fluids. Recently, new pulser-receiver electronics and a new sensor unit were developed by Flow-Viz. The complete sensor unit setup enables non-invasive Doppler measurements through high grade stainless steel. In this work a non-invasive sensor unit developed for one inch pipes (22.5 mm ID) and two inch pipes (48.4 mm ID) were evaluated. Performance tests were conducted using a Doppler string phantom setup and the Doppler velocity results were compared to the moving string target velocities. Eight different positions along the pipe internal diameter (22.5 mm) were investigated and at each position six speeds (0.1–0.6 m/s) were tested. Error differences ranged from 0.18 to 7.8% for the tested velocity range. The average accuracy of Doppler measurements for the 22.5 mm sensor unit decreased slightly from 1.3 to 2.3% across the ultrasound beam axis. Eleven positions were tested along the diameter of the 48.4 mm pipe (eight positions covered the pipe radius) and five speeds were tested (0.2–0.6 m/s). The average accuracy of Doppler measurements for the 48.4 mm sensor unit was between 2.4 and 5.9%, with the lowest accuracy at the point furthest away from the sensor unit. Error differences varied between 0.07 and 11.85% for the tested velocity range, where mostly overestimated velocities were recorded. This systematic error explains the higher average error difference percentage when comparing the 48.4 mm (2.4–5.9%) and 22.5 mm (1.3–2.3%) sensor unit performance. The overall performance of the combined Flow-Viz system (electronics, software, sensor) was excellent as similar or higher errors were typically reported in the medical field. This study has for the first time validated non-invasive Doppler measurements through high grade stainless steel pipes by using an advanced string phantom setup.     

Determination of particle impacts and impact energy in the erosion of X65 carbon steel using acoustic emission technique

An in-situ acoustic emission (AE) monitoring technique has been implemented in a submerged jet impingement (SIJ) system in an effort to investigate the effect of sand particle impact on the degradation mechanism of X65 carbon steel pipeline material in erosion conditions.A detailed analysis of the acoustic events' count rate enabled the number of impacts per second to be quantified for a range of flow velocities (7, 10, 15 m/s) and solid loadings (0, 50, 200, 500 mg/L) in a nitrogen-saturated solution at 50 °C. The number of impacts obtained from acoustic signals showed a strong agreement with theoretical prediction for flow velocities 7 and 10 m/s. A deviation between practical readings and theory is observed for flow velocity of 15 m/s which may be due to error from detected emissions of multiple rebounded particles.Computational fluid dynamics (CFD) was used in conjunction with particle tracking to model the impingement system and predict the velocity and impact angle distribution on the surface of the sample. Data was used to predict the kinetic energy of the impacts and was correlated with the measured AE energy and material loss from gravimetric analysis. The results demonstrate that AE is a useful technique for quantifying and predicting the erosion damage of X65 pipeline material in an erosion–corrosion environment.     

Analysis of load-speed sensitivity of friction composites based on various synthetic graphites

The frictional response of a multi-component phenolic-based friction material is highly complex under a set of variable loads and speeds. The present paper discusses the sensitivity of friction coefficient (μ) of friction composites containing synthetic graphite with different particle sizes (with similar crystallinity range) to braking pressure and sliding speed. The friction studies were carried out on a sub scale brake-test-rig, following 4 loads × 3 speeds experimental design. The best combination of performance properties was observed for the composite containing synthetic graphite with an average particle size of 410 μm. Other particle sizes which resulted in good performance were 38 and 169 μm. Very fine particle sizes were not beneficial for desired combination of performance properties. Regression analysis of μ following an orthogonal L₉(3 × 3) experimental design method revealed that the first order influences of sliding speed and braking pressure were significant. When all the combinatorial influences of braking pressure and sliding speed are taken into account together their simultaneous effects would be most effective in the range of graphite particle size ～80–250 μm.     

Effects of flow patterns and salinity on water holdup measurement of oil-water two-phase flow using a conductance method

This research investigates the effects of flow pattern and salinity of oil-water two-phase flow on water holdup measurement using a conductance method. Firstly, vertical upward oil-water two-phase flow experiment is conducted in a 20 mm inner diameter (ID) pipe, in which the salinities of aqueous solutions are set as 151 ppm, 1003 ppm, 2494 ppm and 4991 ppm respectively. Experimental water-cut and mixture velocity are set as 80–100% and 0.0184–0.2576 m/s. In the experiment, three different flow patterns, i.e., dispersed oil-in-water slug flow (D OS/W), dispersed oil-in-water flow (D O/W) and very fine dispersed oil-in-water flow (VFD O/W) are observed and recorded by a high speed camera. Meanwhile, we collect the response of Vertical Multiple Electrode Array (VMEA) conductance sensor excited by a sine voltage signal. The result shows that, for VFD O/W, the water holdup from VMEA sensor shows a satisfied agreement with that of quick closing valve (QCV) method under certain salinities, i.e., 1003 ppm as well as 2494 ppm. For D OS/W flow and D O/W flow characterized by dispersed oil droplets with various sizes, considerable deviations of water holdup between VMEA sensor and QCV method under four kinds of salinity aforementioned are presented. Afterward, according to experimental analysis along with theoretical deviation, it is concluded that the deviation of the measurement system reaches its minimum when reference resistance in the measurement circuit and salinity of the aqueous solution satisfy constraint conditions, and the accuracy of water holdup using the conductance method can be improved through adjusting reference resistance to match the salinity of water phase. Finally, the recurrence plot algorithm is utilized to identify typical flow patterns mentioned above and it shows satisfied results on comprehending the discrepancies among different flow patterns, demonstrating that the recurrence plot algorithm can be effectively applied in flow pattern identification regarding oil-water flows.     

Effect of soft carbon black on tribology of deproteinised and polyisoprene rubbers

In this work, the tribological properties of deproteinised natural rubber (DPNR) were examined and compared with synthetic cis-1,4-polyisoprene rubber (IR), namely Natsyn 2200. The effect of adding carbon black (CB) (0, 25 and 50 phr) to both DPNR and IR on the friction and wear characteristics was investigated. Dry abrasion tests were carried out using pin-on-cylinder tribometer with abrasive paper (Diamond 50) under different operating test conditions such as applied normal load (5–35 N), sliding speed (0.3–1.5 m/s) and sliding distance (90–450 m).Experimental results showed that the addition of CB has significantly affected the wear and friction characteristics of both DPNR and IR, i.e. it reduces the abrasion weight loss by more than 70% compared to unfilled rubber, depending on the test conditions and the concentration of CB. The friction coefficient of DPNR was decreased by about 12.5% upon the addition of 50 phr CB, compared to unfilled DPNR. Meanwhile, adding (25–50 phr) CB to IR drastically deteriorates the friction coefficient, i.e. an increase in the friction by about 200% at 25 phr CB and 300% at 50 phr CB compared to unfilled IR.Finally, scanning electron microscopy (SEM) technique is employed to observe the abrasion pattern of rubber in order to correlate the experimental test results to the wear mechanisms.     

Measurement and analysis of fluorescent whitening agent content in soybean milk based on image techniques

This paper presents a method for measuring and quantitatively analyzing the fluorescent whitening agent in soybean milk based on image techniques. After collecting the fluorescent images of the soybean milk samples, the top seven wavelet moment invariants are selected according to the sample training and experimental comparison. Then calculate the standard templates of the 49 classes of calibration samples with different fluorescent whitening agent content ranging from 0.02 mg/ml to 0.5 mg/ml. The minimum distance method is carried out to match the testing sample with the calibration template, which realizes the quantitative analysis. To verify the effectiveness of the presented method, the prediction experiment is carried out. Results show that the absolute errors are within 0.005 mg/ml and the relative errors are within 5%, which means this method can measure the fluorescent whitening agent in soybean milk. This research presents a new approach for detecting the illegal fluorescence additive in food production.     

Improved wear resistance in alumina-PTFE nanocomposites with irregular shaped nanoparticles

Past studies with PTFE nanocomposites showed up to 600× improvements in wear resistance over unfilled PTFE with the addition of Al₂O₃ nanoparticles. Irregular shaped nanoparticles are used in this study to increase the mechanical entanglement of PTFE fibrils with the filler. The tribological properties of 1, 2, 5 and 10 wt.% filled samples are evaluated under a normal pressure and sliding speed of 6.3 MPa and 50.8 mm/s, respectively. The wear resistance was found to improve 3000× over unfilled PTFE with the addition of 1 wt.% nanoparticles. The 5 wt.% sample had the lowest steady state wear rate of K = 1.3 × 10⁻⁷ mm³/N m and the lowest steady friction coefficient with μ = 0.21.     

Quasi-constant rotational stiffness characteristic for cross-spring pivots in high precision measurement of unbalance moment

This paper proposes a design method for cross-spring pivots with quasi-constant rotational stiffness in the field of unbalanced moment measurement. To achieve high precision measurement of unbalance moment, the relationship between instrument sensitivity and the rotational stiffness of the cross-spring pivot is revealed. In order to eliminate the impacts of payload changes on instrument sensitivity, the relationship between geometric parameters and the rotational stiffness of the pivot is studied. Further, cross-spring pivots with quasi-constant rotational stiffness are designed as the rotation unit of a static balancing instrument, while the center shift of pivot takes the minimum value. Certain amount of unbalance moments is measured by the instrument. Experimental studies of the instrument show that the maximum measurement errors of unbalance moments 0.162 g mm, 0.319 g mm and 1.300 g mm are 0.068 g mm, 0.086 g mm and 0.053 g mm, respectively, when the payload ranges from 0 g to 7000 g. The instrument can achieve a relatively high precision measurement and the instrument sensitivity is almost not affected by the changes of payloads. The effectiveness of the method and the stiffness property of the pivot are verified by the experiments. So this kind of pivot has good prospects in unbalance moment measurement.     

In-plane dead reckoning with knee and waist attached gyroscopes

This paper presents a Micro-Electro-Mechanical (MEM)-based system which comprises of two inertial sensors (gyroscopes) for indoor personal navigation. In this system, the position and orientation of a moving person on a flat surface (zero-slope) is determined through strategically placed sensors on the waist and knee of the human body. From the knee attached gyroscope, this system takes advantage of the repetitive angular displacement during each step of the walking person to bound the angular displacement error. Our algorithm continuously estimates the heading by integrating the measured angular rates from the waist attached gyroscope. Results show that on a flat surface, the average tracking error of 0.1935 m with a standard deviation 0.0512 m for total distance traveled of 62.32 m.     

Effect of ozone pretreatment on the physical and mechanical properties of particleboard panels made from bagasse

The main objective of this study was to investigate the applied properties of particleboard panels made from bagasse, which were either treated or not treated with gaseous ozone (O₃). Variable parameters were ozone exposure time (1–3 min) at 9 ppm and storage period (1–5 months). Other parameters such as resin content (12 wt%), hardener content (1 wt%), type of hardener (NH₄Cl), press closing time (5 mm/s), board density (0.70 g/cm³), and press pressure (30 kg/m²) were held constant. The experimental panels were tested for their mechanical properties including modulus of elasticity (MOE), modulus of rupture (MOR); and internal bonding strength (IBS) and physical properties in terms of water absorption (WA) and thickness swelling (TS) according to the procedures defined by EN standards. Overall results showed that all panels made from treated bagasse exceeded the EN standards for MOE, MOR, and IBS. However, WA and TS values decreased after ozone pretreatment compared to the un-treated (control) panels. Application of Duncan’s Multiple Range Test for the mean values of the results showed that the effects of both variables, except their interactions, on the mechanical and physical properties were highly significant (p ⩽ 0.01%). All the mechanical properties of the panels decreased when the treatment duration increased from 1 to 5 months.     

Wear resistance of Cu–Ni–Mo austempered ductile iron

A series of ductile iron samples alloyed with 0.66% Cu, 1.02% Ni, and 0.26% Mo were austempered at 315 and 370 °C for 5–240 min and then tested for wear strength. A block-on-ring wear testing machine was used for this purpose. The wear samples were tested under a load of 45 N and a displacement speed of 2.40 m/s. The experimental outcome indicates that the wear properties of the austempered ductile iron (ADI) are strongly influenced by the exhibited microstructure. In particular, optimal wear properties were found in samples austempered at 370 and 315 °C for 90 and 120 min, respectively. These heat treatment times are long enough to promote the development of a relatively high volume fraction of high carbon retained austenite concomitant with ferrite and a fine dispersion of carbides. After wear testing, scanning electron microscopy (SEM) observations on the wear samples did not show any evidence of a transformation-induced-plasticity (TRIP). Hence, the experimental evidence suggests that the dominant wear mechanism was delamination associated with sub-surface crack formation and final wear particle debris removal.     

Enhancing electrical conductivity and electrical thermal characteristics of a PEDOT:PSS thin layer by using solvent treatment and adding Ag nanoparticle solution

A method of enhancing the electrical conductivity of 3,4-ethylenedioxythiophene:poly styrene sulfonate (PEDOT:PSS) by combining solvent treatment (adding high polar solvent: 5 wt% ethylene glycol) and adding a small amount of silver (Ag) nanoparticles in a solution was investigated. The main purpose of this was to apply a PEDOT:PSS conductive layer to micro-thermal devices driven by electricity and, for this, to reduce the layer thickness (for low stiffness) while maintaining necessary high electrical conductivity. Layers with thicknesses of less than about 10 μm were examined for electrical conductivity and temperature when electricity was applied. The solvent treated PEDOT:PSS had suitable electrical resistance to generate appropriate temperature properties. The added Ag nanoparticles reduced the electrical resistance by 30–70% over the measured thickness range. The electric conductivity applied with this method was 200–260 Ω⁻¹ cm⁻¹ for thicknesses of 1–2 μm (conductive area: 12 mm × 10 mm) and the generated temperature increase was 20–50 °C at applied voltages of 3–5 V. These characteristics are considered to be suitable to use the conductive layer as a heating element. In addition, the method we used scarcely degraded the transparency of the layer. Measurements of the conductive area in a layer with conductive atomic force microscope (AFM) indicated that the added Ag nanoparticles contributed to increasing the conductive areas and distributing them more uniformly.