Vibration and displacement analysis during turning of hardened steel

A low-cost approach for three-dimensional (3-D) full-field displacement measurement is applied for the analysis of large displacements involved in two different mechanical events. The method is based on a combination of fringe projection and two-dimensional digital image correlation (DIC) techniques. The two techniques have been employed simultaneously using an RGB camera and a color encoding method; therefore, it is possible to measure in-plane and out-of-plane displacements at the same time with only one camera even at high speed rates. The potential of the proposed methodology has been employed for the analysis of large displacements during contact experiments in a soft material block. Displacement results have been successfully compared with those obtained using a 3D-DIC commercial system. Moreover, the analysis of displacements during an impact test on a metal plate was performed to emphasize the application of the methodology for dynamics events. Results show a good level of agreement, highlighting the potential of FP + 2D DIC as low-cost alternative for the analysis of large deformations problems.

Holographic interferometry and speckle application are powerful techniques for deformation, displacement and vibration analysis especially when they can be applied in real time. Bismuth Silicon Oxide crystals Bi₁₂ Si 0₂₀ (BSO) were used for real-time deformation displacement and vibration analysis using holography and "speckle photography". After a short introduction of holographic interferometry for deformation measurement using BSO crystals, speckle applications for deformation, displacement and vibration analysis in real time will be discussed.

C6 glioma cells were used as a model system to study the regulation of EAAC1-mediated Na(+)-dependent L-[3H]glutamate transport. Although a 30-min preincubation with forskolin had no effect on transport activity, preincubation with phorbol 12-myristate 13-acetate (PMA) increased transport activity two- to threefold. PMA caused a time-dependent and concentration-dependent increase in EAAC1-mediated L-[3H]glutamate transport activity. A 2-min preincubation with PMA was sufficient to cause more than a twofold increase in transport activity and the protein synthesis inhibitor cycloheximide had no effect on the increase. These data suggest that this increase is independent of protein synthesis. The EC50 value of PMA for stimulation of transport activity was 80 nM. Kinetic analyses demonstrated that the increase in transport activity was due to a 2.5-fold increase in Vmax with no change in Km. PMA also increased the transport of the nonmetabolizable analogue, D-[3H] aspartate to the same extent. In parallel assays, PMA did not, however, increase Na(+)-dependent glycine transport activity in C6 glioma. The inactive phorbol ester alpha-phorbol 12,13- didecanoate, did not stimulate L-[3H]glutamate transport activity, and the protein kinase C inhibitor chelerythrine blocked the stimulation caused by PMA. Okadaic acid and cyclosporin A, which are phosphatase inhibitors, had no effect on the stimulation of transport activity caused by PMA. The Ca2+ ionophore A23187 did not act synergistically to increase PMA stimulation. In previous studies, PMA caused a rapid increase in amiloride-sensitive Na(+)/H+ transport activity in C6 glioma. In the present study, pre- and coincubation with amiloride had no effect on the stimulation of transport activity caused by PMA. These studies suggest that activation of protein kinase C causes a rapid increase in EAAC1-mediated transport activity. This rapid increase in Na(+)-dependent L-[3H]-glutamate transport activity may provide a novel mechanism for protection against acute insults to the CNS.

With the continuous development of milling technology and the increasing number of slim hole plugging removal operations worldwide, how to guide operators to select reasonable working parameters to achieve efficient plugging removal has become a problem worth paying attention to. At present, the research on the optimization of working parameters based on the characteristics of plugging material is not complete. In order to explore the feasibility of efficient unplugging operation with low weight on bit and high rotational speed in slim hole, this paper chooses cement plug as plugging material, and uses Mechanical Specific Energy (MSE) and Rate of Penetration (ROP) as the evaluation index of plugging efficiency. A test bench was established and a low WOB milling test was designed. Meanwhile, a 3D simulation model of full-size PDC bit milling cement plug was established. Through the test and numerical simulation analysis, it is found that when the bit weight is enough to destroy the blockage, efficient operation can be realized under the working condition of low WOB and high rotational speed. A working parameter optimization method is proposed, and the recommended working interval is 3 kN WOB and 1500 ~ 2000 r/min rotational speed; 5 kN WOB, 1000 r/min rotational speed. The results show that the increase of WOB and rotational speed can improve the ROP of the bit, and it is feasible to use rotational speed to compensate the WOB to increase the ROP. In simulation and test, the efficiency of milling plugs is not good when the WOB is lower than 3 kN. To achieve high efficiency milling plugs, the priority should be to ensure that the WOB is enough to allow the cutter to normally break the plug. When analyzed with power drilling tools in conjunction with downhole motors, the ROP obtained by PDC bit with turbodrill under the condition of low WOB and high rotational speed is better than that obtained by a positive displacement motor with high WOB and low rotational speed, the results highlight the advantages of low WOB and high rotational speed milling cement plug. This paper provides a new idea for the optimization of working parameters of coiled tubing during plugging removal in slim holes.

Rapid increases in traffic volumes in countries such as Malaysia may lead to exposure to poor air quality both outdoors and indoors. This study investigated asthma symptoms among Malaysian schoolchildren in relation to indoor and outdoor air pollution in urban and semi-rural settings in a school-based cross-sectional study of 1,952 schoolchildren living in urban and semi-rural areas. Parents completed a questionnaire including questions on asthma symptoms and environmental risk factors. Air pollutant concentrations were measured at 16 schools. Analysis used multiple logistic regression controlling for sociodemographic and indoor air pollution factors. A total of 11.4, 7.6, 9.5 and 7.0 % schoolchildren had asthma, current wheeze, dry cough at night and wheezing after exercise, respectively. Asthma and dry cough were significantly higher among urban schoolchildren. A 10-μg/m3 increase in outdoor NO2 level was associated with a twofold increase in the reporting of current wheeze (odds ratio (OR) 1.90; 95 % confidence interval (CI) 1.02–3.52); a 10-μg/m3 increase in indoor PM2.5 was similarly associated with a twofold increase in the reporting of wheeze during exercise (OR 2.08; 95 % CI 1.02–4.26). Secondhand smoke (SHS), mold and the presence of new furniture at home were also linked to asthma symptoms. NO2 concentrations in urban Malaysia frequently exceed those of the international standards. Exposure to traffic-related air pollution may be linked to asthma symptoms among children in Malaysia.

Design and stress analysis of a high speed rotor for an advanced induction motor

Today, short- and long-term structural health monitoring of bridge infrastructures and their safe, reliable and cost-effective maintenance have received considerable attention. For this purpose, image-assisted total station (here, Leica Nova MS50 MultiStation) as a modern geodetic measurement system can be utilized for accurate displacement and vibration analysis. The Leica MS50 measurements comprise horizontal angles, vertical angles and distance measurements in addition to the captured images or video streams with practical sampling frequency of 10 Hz using an embedded on-axis telescope camera. Experiments were performed for two case studies under (1) a controlled laboratory environment and (2) a real-world situation observing a footbridge structure using a telescope camera of the Leica MS50. Furthermore, two highly accurate reference measurement systems, namely, a laser tracker Leica AT960-LR and a portable shaker vibration calibrator 9210D in addition to the known natural frequencies of the footbridge structure calculated from the finite element model analysis are used for validation. The feasibility of an optimal passive target pattern and its accurate as well as reliable detection at different epochs of time were investigated as a preliminary step. Subsequently, the vertical angular conversion factor of the telescope camera of the Leica MS50 was calibrated, which allows for an accurate conversion of the derived displacements from the pixel unit to the metric unit. A linear regression model in terms of a sum of sinusoids and an autoregressive model of the coloured measurement noise were employed and solved by means of a generalized expectation maximization algorithm to estimate amplitudes and frequencies with high accuracy. The results show the feasibility of the Leica MS50 for the accurate displacement and vibration analysis of the bridge structure for frequencies less than 5 Hz.

The green alga Selenastrum minutum (Naeg.) Collins is able to assimilate NH(4) (+) in the dark under anaerobic conditions (GC Vanlerberghe, AK Horsey, HG Weger, DH Turpin [1989] Plant Physiol 91: 1551-1557). In the present study, analysis of metabolites following addition of NH(4) (+) to cells acclimated to anaerobic conditions has shown the following. There was a transient decline in adenylate energy charge from 0.6 to 0.4 followed by a recovery back to ~0.6. This was accompanied by a rapid increase in pyruvate/phosphoenolpyruvate and fructose-1,6-bisphosphate/fructose-6-phosphate ratios indicating activation of pyruvate kinase and 6-phosphofructokinase, respectively. There was also an increase in fructose-2,6-bisphosphate, which, since this alga lacks pyrophosphate dependent 6-phosphofructokinase can be inferred to inhibit gluconeogenic fructose-1,6-bisphosphatase. These changes resulted in an increase in the rate of anaerobic starch breakdown. Anaerobic NH(4) (+) assimilation also resulted in a two-fold increase in the rate of production of the major fermentative end-products in this alga, d-lactate and ethanol. There was no change in the rate of accumulation of the fermentative end product succinate but malate accumulated under anoxia during NH(4) (+) assimilation. A rapid increase in Gln and decline in Glu indicates that primary NH(4) (+) assimilation under anoxia was via glutamine synthetase-glutamate synthase. Almost all N assimilated under these conditions was sequestered in alanine. These results allow us to propose a model for the regulation of carbon metabolism during anaerobic NH(4) (+) assimilation.

Deep-groove ball bearings for the eAxles of electric vehicles must adapt to higher rotational speed conditions because the speed of eAxle motors have been increasing as the size and weight of the motors decrease. Therefore, understanding the oil-lubricated conditions inside ball bearings at high rotational speeds is essential for optimizing their design for eAxles. To clarify the oil-lubricated conditions inside ball bearings at these high speeds, a new test apparatus was developed. This apparatus is capable of simultaneously measuring the friction torque of deep-groove ball bearings, the oil-film thickness on the rolling balls, and observing the oil distributions inside the bearings at rotational speeds up to 20,000 min-1. The oil-film thickness was measured using three-wavelength optical interferometry, and the oil distribution was observed using fluorescence. It was found that the oil-film thickness became constant at rotational speed conditions exceeding approximately 7,700 min-1. Oil starvations were observed on the raceway around the rolling ball, and these regions increased with increasing rotational speeds. Additionally, in the deep-groove ball bearing with a crown-shaped cage, the oil was mainly supplied to the rolling balls from the inner ring side through the space between the cage claws that held the ball. Moreover, the amount of mixed air tended to increase as the rotational speed increased to approximately 7,700 min-1. Those oil starvations and increasing air in oils were considered to be factors that prevent the increase in oil-film thickness. The findings of the reported study will contribute to the development of multibody dynamic technology for high-speed ball bearings necessary in electric vehicles.

We propose a high-speed and precise gap servo control system that is based on the feed-forward control method that can reduce the harmonic disturbance (RHD-FFC) on a near-field optical recording system with a solid immersion lens. An optical disk of 1.2 mm thickness rotates with about 30 µmp–p of axial run-out. The axial run-out prevents a gap servo from performing precisely at high rotational speed. The RHD-FFC method can suppress harmonic disturbances of gap error signal and can perform at high speed while keeping less than 25 nm of gap length between an optical head and a rotational disk surface. We confirmed that the gap servo applying the RHD-FFC method performed precisely and achieved at high disk rotational speed of 11000 rpm with a 1.2-mm-thick optical disk with a track pitch of 0.16 µm, corresponding to a data capacity of 100 Gbyte.

We propose a high-speed and precise gap servo control system that is based on the feed-forward control method that can reduce the harmonic disturbance (RHD-FFC) on a near-field optical recording system with a solid immersion lens. An optical disk of 1.2 mm thickness rotates with about 30 µmp–p of axial run-out. The axial run-out prevents a gap servo from performing precisely at high rotational speed. The RHD-FFC method can suppress harmonic disturbances of gap error signal and can perform at high speed while keeping less than 25 nm of gap length between an optical head and a rotational disk surface. We confirmed that the gap servo applying the RHD-FFC method performed precisely and achieved at high disk rotational speed of 11000 rpm with a 1.2-mm-thick optical disk with a track pitch of 0.16 µm, corresponding to a data capacity of 100 Gbyte.

Arctic permafrost soils have recently been identified as the largest mercury (Hg) reservoir on Earth. Today, rapid warming in the high latitudes may be altering the Arctic Hg cycle by accelerating permafrost thaw, leading to changes including deepening of the active layer, increasing organic matter decay, and increasing seasonal groundwater flow. However, few studies have investigated how the Hg cycle has responded to past changes in climate, and there is a lack of Arctic records that span the late glacial to early Holocene when climate conditions changed abruptly. We propose that the geochemical and physical changes in the sediment record of Burial Lake (68.43ºN, 159.17ºW; 460 m ASL), which document climatic and environmental changes in northwestern Alaska after the Last Glacial Maximum (LGM), can be used as an analog to investigate how today’s rapid warming affects Hg mobilization from permafrost soils to surficial waters. Warming in the Northern Hemisphere between ~15.0 and 8.0 ka resulted in rapid changes in northwest Alaska, including the submergence of the Bering Land Bridge that reconnected the Pacific and Arctic Oceans (~11.0 ka), in addition to changes in the hydroclimate. Our results indicate that the Hg concentration was relatively low and stable in the Burial Lake record during the transition from the LGM to the late glacial (20.0 and 16.0 ka) with a mean concentration of 64±7 μg/kg. Mercury concentrations begin to increase after 16.0 ka. Then, coinciding with a rapid temperature increase at the beginning of the Bølling Allerød (14.7 to 12.9 ka), Hg concentrations increased by ~20% and showed higher variability as temperatures fluctuated until the end of the Younger Dryas (12.9 to 11.7 ka). At 11.0 ka, the Hg concentration increased rapidly. It peaked at 140 µg/kg, with a mean Hg concentration of 119 μg/kg between 11.0 to 8.8 ka, coinciding with evidence of a rapid increase in regional precipitation and flooding of the Bering Land Bridge. From 8.8 to 0.1 ka, the mean Hg concentration decreased to 107 μg/kg and then increased rapidly over the last 100 years to a maximum concentration of 196 μg/kg occurring during the 1990s. Throughout the majority of the Burial Lake sediment record, the Hg concentration is most strongly correlated with total organic carbon content and geochemical proxies sensitive to changes in redox conditions. We interpret this finding as an indication that a large fraction of Hg is mobilized from the lake catchment along with dissolved organic matter (DOM), iron (Fe), and manganese (Mn) that are mobilized as a result of saturation and deepening of the active layer during periods of warmer, but most importantly, wetter climate. The Hg record from Burial Lake suggests that as the climate warmed after the LGM, organic-rich permafrost soils and Hg accumulated in the catchment. The sudden increase in Hg mobilization from permafrost soils was then initiated at the onset of the Holocene due to the rapid increase in precipitation that coincided with the flooding of the Bering Land Bridge.

The Space Transportation System has been planned as an evolving system, implementing new technologies that increase safety and reliability of Reusable Launch Vehicles, and innovative materials and joining technologies have been developed at NASA Marshall Space Flight Center (MSFC).In the framework of the Friction Stir Welding upgrade of the Space Shuttle External Tank, it has been spent an effort in defining a simple and reliable process, that take advantage of the high rotational speed of the pin tool. The author conducted at NASA MSFC a feasibility study for the High Speed Friction Stir Welding (HSFSW) process and the research consisted of three main phases: 1. theoretical modeling of the HSFSW process. 2. design and manufacturing of the HSFSW machine. 3. DOE and lab analyses of the experimental joints. The High Speed FSW process has been modeled implementing the “Rotating plug model” developed at NASA, and based on the Plastic-Analytic approach, which consist in superposing two flows : a primary flow comprising a plug of metal rotating with the pin tool and shearing over a cylindrical surface, and a secondary flow driven by threads on the pin and resembling a ring vortex around the pin. The model has been tested during phase 3 with some modifies to validate it in the high speed rotation condition: Parametric evaluation of conditions for surface slip. Flow stress at high temperatures and influence of the material characteristics (Al2219-Al2195). Once determined the main process parameters it has been designed the FSW system. It consisted in three main sub phases : 1. motor characteristics and machine design 2. process control 3. pin tools design. The factors that influenced this phase has been requirements imposed for Space application and for a technology transfer. Essential characteristics of the High Speed FSW machine are : light weight, low power consumption, high rotational spindle speed, forces and torque equilibrium of the whole system, easy to handle. The third phase consisted in planning the tests, according with the DOE method, considering the theoretical model values and the machine parameters. The main parameters are : Material (composition, thickness, surface) Pin tool (length, diameter, taper angle) Shoulder (length, diameter, taper angle) Machine (travel speed, RPM, angle, penetration) Finally lab tests has been conducted to evaluate the quality of the joints (Macro pictures, Xray, Ultrasonics). The standard NASA testing procedure for welded Space vehicles components has been adopted and the results showed excellent microstructural and mechanical properties of the FSW welded joints.The feasibility study was successfully completed, proving a new technology, with possible application in Space. Long duration space flights requires a repair technique in Space and compared to all the other joining techniques available, the High Speed Friction Stir Welding appears to be the best one, for its simplicity , reliability , quality and safety. The material is new and original, as part of a research conducted at MSFC, NASA, and its content has not been presented to previous meetings. The author take responsibility to deliver the paper in Bremen.

Stationary shoulder friction stir welding has been used to weld 4-mm-thick 2219-T6 aluminium alloy at high rotation speeds. Strain plastic damage was applied to demonstrate the formation mechanism of welding defects at high rotation speeds above 2000 rpm. A three-way converging zone in the joint, in which materials of different microstructure characteristics converged from three directions during high tool rotation speed welding, was found. At the relatively high tool rotation speed, the significant differences in the microstructures would result in weld defects in this zone. It could be attributed to material toughness damage at high strain rate. With increasing tool rotation speed, the tensile strength of the joint constantly decreased. When the tool rotation speed varied from 2000 to 2600 rpm, the tensile strength decreased from 305 MPa (68.2% of the BM) to 238 MPa (53.2% of the BM).

Electroless plating, unlike electroplating, enables the application of metallic coatings without the need of providing electronic pathway to the plated region. As such, electroless plating is used to metalize non-conductive substrates and electrically isolated features. In semiconductor device metallization, electroless copper deposition is particularly advantageous for metalizing extremely small (nm scale) features because the process does not require a conductive seed layer. However, void-free metallization of vias and trenches typically requires bottom-up plating of the patterned feature, corresponding to high plating rate at the feature bottom and inhibited plating on the feature sidewalls, rim, and the top flat substrate. This is enabled in electrolytic plating by a special additives mixture that is not effective in the electroless system. In the absence of molecular level mechanistic understanding of the interaction between the additives and the plating process, the search for more effective additives is typically conducted empirically. However, the conventional injection technique,1,2 that provides rapid screening of electroplating additives by measuring the voltage transient following additives injection, is not applicable to the electroless system. Consequently, testing of additives for bottom-up fill in electroless systems entails actual plating of features and their microscopic examination, requiring significant effort and time. Further complication arises due to the fact that the additives containing electroless system is significantly more sensitive to transport and agitation than its electrolytic counterpart. Presented here is a novel approach providing simple and rapid screening of additives applicable to electroless systems. The technique is based on electroless plating of a flat (featureless) rotating disk electrode. Two electroless plating experiments are conducted in the same tested electrolyte: one, with the disk rotating at a high speed, and the second, at a low rotation rate, measuring in both experiments the electroless plating rate from the deposit amount. As illustrated schematically in Fig. 1, we look for an additives mixture that provides a low plating rate at the high rotation speed (which corresponds to the high transport rates and thin boundary layer prevailing on the flat substrate and feature rim), and a high plating rate at the low rotation speed (simulating the thick boundary layer at the bottom of the feature). The high rotation speed, ω1, which relates to the mass transport boundary layer thickness, δ1 through the Levich equation3 [Eq 1], is selected such that it corresponds to the relatively high transport rates prevailing over the flat substrate. In equation 1, D and ν are the additive’s diffusivity and the electrolyte kinematic viscosity, respectively. The low rotation rate, ω2, is selected to simulate the hindered transport of the additive to the feature bottom, corresponding the significantly larger mass transport boundary layer, δ2. The equality on the left-hand side of equation 2, can be derived following the analysis of Adolf and Landau4, where L and R are the feature’s depth and width, respectively, Γ is the additive surface saturation concentration, and Cb is its bulk concentration. ω2is selected from the equality on the right-most side of equation 2. As shown in Figure 2, in the absence of additives, the electroless plating rate increases with rotation rate, as copper transport is enhanced. This system is not expected to provide bottom-up fill, since the deposition rate will be higher on the via rim and the flat top substrate. However, utilizing 1.5 ppm mercaptopropanesulfonic acid (MPS) as an inhibiting additive, leads to the desired significantly lower plating rates at higher rotation speeds, as compared to those at lower rotation speeds. This is most likely due to the enhanced transport towards the substrate of the low concentration inhibitor at the higher rotation rates. Consequently, MPS is a promising additive for promoting bottom-up electroless plating of recessed features. Unfortunately, MPS by itself yields a dark and nonuniform deposit, so polypropylene glycol and dipyridyl were added to generate a bright and uniform deposit. Additional analysis and further experimental details are provided in the presentation. Acknowledgements Atotech GMBH is acknowledged for funding this study and for providing helpful input. References R. Akolkar and U. Landau, J. Electrochem. Soc., 151, C702 (2004).Lindsay Boehme and Uziel Landau, J. Appl. Electrochem., 46(1), 39-46 (2016).V. G. Levich, “Physicochemical Hydrodynamics”, Prentice-Hall, 1962.James Adolf and Uziel Landau, J. Electrochem. Soc., 158 (8) 1-8 (2011). Figure 1