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2,4-Dichlorophenol (2,4-DCP) is difficult to degrade rapidly in the environment due to its stable chemical properties, so it was easy to lead to serious chlorophenol pollution in soil. Consequently, a remediation method which is efficient, safe, and economical is required. In this study, electrokinetic (EK) remediation was used to transfer sodium persulfate (Na2S2O8) into soil to degrade 2,4-DCP, and the effect of several factors (including the addition location of Na2S2O8, applied voltage, and running time) on the remediation efficiency was explored. The concentration of Na2S2O8, residual efficiency of 2,4-DCP and distribution characteristics of pH, and electrical conductivity were analyzed. The results showed that the cathode was the optimal position to add Na2S2O8. Under this condition, Na2S2O8 was uniformly distributed in the whole soil column through electromigration. The optimal removal efficiency of 2,4-DCP in soil by adding Na2S2O8 was approximately 26% when the voltage gradient was 1.0 V/cm and the operating time was 9 days, which was mainly due to the degradation of S2O82−. [ABSTRACT FROM AUTHOR]

Compared with spray gun spraying, electrostatic spray rotating bell (ESRB) spraying can provide better film forming quality and higher adhesion rate, which is more suitable for the automobile painting. However, the complexity of the automobile surface geometry and the spray pattern produced by ESRB painting makes the trajectory planning and the determination of spraying parameters challenging. This research presents a coating thickness distribution model for ESRB atomizer with uniform motion and establishes a parametric model to express the functional relationship between the thickness distribution model and atomizer parameters. The proposed parametric model aims to provide a guideline for the determination of spraying parameters in the process of off-line programming in the painting industry. Firstly, a novel feature points fitting distribution model was established based on the characteristics of ESRB uniform linear spraying coating. The model can fully visualize the cumulative profile characteristics of coatings. Secondly, the orthogonal experiment, multilevel and multifactor, was designed to analyze the variation of feature points with the painting parameters. Then, based on the requirements of the spraying process, an objective function is established for the coating thickness and other indicators of each area, and a genetic algorithm is used to solve it, so as to determine the ESRB spraying parameters. Finally, three simulation experiments show that the new model is effective and has high prediction accuracy, which can be effectively applied to the ESRB spraying system. [ABSTRACT FROM AUTHOR]

Compared with spray gun painting, electrostatic spraying rotating bell (ESRB) painting can provide better film-forming quality and higher adhesion rate, which is more suitable for automobile base coating. However, the complexity of the spray pattern of the ESRB and the automobile surface geometric makes the spray process planning a more challenging problem. This paper aims to provide a new parameterized model of the ESRB to facilitate the thickness calculation and trajectory planning in the off-line painting programming. Firstly, according to the distribution characteristics of paint particles and the force analysis of adhesion process, a new static deposition rate model—offset asymmetric Gaussian model is proposed on the plane. The parameters in the new model have intuitive practical significance and can fully reflect the characteristics of ESRB coating deposition rate. Then based on the analysis of the relationship between the static model and uniform linear spraying deposition, the static model is established by measuring the layer data of corresponding uniform linear spraying. In order to further simulate the paint thickness on curved surfaces, the projection model with variable spraying distance and deposition point normal deflection is also deduced. Finally, a parameterized static model and sampling points library are established which provide efficient and accurate prediction of static deposition result, and is more suitable for off-line programming. Three different groups of simulation proved that the proposed static deposition rate model has high calculation accuracy for different working conditions and fast simulation speed for different spraying parameters. [ABSTRACT FROM AUTHOR]

Variations in running conditions cause fluctuation in the temperature field of precision machine tools, which inevitably results in thermal errors. To meet the demands of dynamic and time-varying temperature control capability, an active temperature control (ATC) method based on time grating principle is proposed, and the ATC system is developed. The ATC system contains main-loop and sub-loops. The oil target temperature in the sub-loop is determined according to the running parameters and the matching principle of the generalized heat generation–dissipation power. In accordance with the time grating principle, dynamic and differential oil temperature control of each sub-loop is achieved via the inlet time regulation of high-temperature (H-t) or low-temperature (L-t) oil in the main-loop. The main-loop H-t and L-t oil target temperatures are determined by the target range of the sub-loop temperature. The dynamic distribution of the refrigeration capacity and proportional heating mode is adopted to control the temperatures of H-t and L-t oil. By focusing on the feed system of precision machine tool, we carry out both dynamic simulation study and verification experiments, and the results show that the ATC method and system can effectively regulate the temperature field of precision machine tools, thus improving the thermal accuracy of the precision machine tool. [ABSTRACT FROM AUTHOR]

Error compensation is an effective method to guarantee the machining accuracy of machine tools. This paper proposes a method for geometric error identification and compensation of CNC machine tools based on volumetric diagonal error measurements. A geometric error model for CNC machine tools was established. Thereafter, the error measurement principle of the laser tracker was established. Based on this characteristic, error identification equations used to describe the position-dependent geometric errors were derived based on polynomials. A regularisation method was then selected to identify geometric error parameters. The identified geometric errors could be substituted in the space compensation module for error compensation. This paper takes a horizontal three-axis machining centre as an example to illustrate the proposed method. Results of the experiment reveal that the error identification and compensation method is convenient and effective in reducing volumetric diagonal errors. Moreover, the final volumetric diagonal positioning error with compensation was controlled at approximately 20 μm. [ABSTRACT FROM AUTHOR]

Generally, the accuracy stability of a precision motorized spindle unit is influenced by its structural thermal balance behaviors (power matching degree of spindle structural heat generation–dissipations). For the accurate analysis of this spindle heat transfer behaviors based on temperature detections, this paper describes a method constructed with the numerical simulation technology and a proposed genetic algorithm-extreme learning machine (GA-ELM) algorithm. Firstly, the heat–fluid–solid coupling FE transient model is established to simulate spindle thermal behaviors, determinations of its thermal loads/boundary conditions are initially based on empirical calculations. Secondly, according to spindle temperature detections, these initial values are applied to thermal simulations and corrected by GA to make simulated spindle temperatures gradually approach detections. Specially, ELM is adopted to estimate the functional relationships from the parent population to the child population generated by genetic operators with increasing fitness values, and the trained ELM model is utilized to ensure the GA faster convergence. Eventually, based on the corrected thermal load/boundary condition values and simulation results, the time-varying power matching conditions of spindle structural heat generation–dissipation are analyzed. This study provides a theoretical basis for the optimization and promotion of spindle structural design and coolant control strategy. [ABSTRACT FROM AUTHOR]

A novel orthogonalization-free method together with two specific algorithms is proposed to address extreme eigenvalue problems. On top of gradient-based algorithms, the proposed algorithms modify the multicolumn gradient such that earlier columns are decoupled from later ones. Locally, both algorithms converge linearly with convergence rates depending on eigengaps. Momentum acceleration, exact linesearch, and column locking are incorporated to accelerate algorithms and reduce their computational costs. We demonstrate the efficiency of both algorithms on random matrices with different spectrum distributions and matrices from computational chemistry. [ABSTRACT FROM AUTHOR]

The support point layout has an important influence on the working performance of the machine tool, when the material, manufacturing process, and internal structure of machine bed are given. In order to ensure the performance, stability, and anti-interference of precise machine tool, this paper presents an optimized design method of 3-point support for T-shaped bed of precision horizontal machining center. This article first establishes the statics model of the T-shaped bed and analyzes grillage beam model used to characterize the main static deformation trend of the bed based on the singular function method. After verifying the rationality of the model through simulation, the optimized 3-point support position can be obtained. Then this paper measured the deformation of the upper surface of a simple bed due to gravity. The deviation between the experimental results and the simulation results is less than 20%, which verifies the reliability of the simulation and theoretical results. Based on the ISIGHT multidisciplinary optimization platform, this paper completes the multi-objective optimization of the support point layout of the bed, and the optimization results prove the accuracy of the theoretical model. This paper takes the bed of M800H precision horizontal machining center as an example to illustrate the application process of the proposed method. Then, the optimization effect of the bed and the static characteristics of the whole machine by simulation are compared. The maximum deformation of the bed has reduced by 27.1%. In the whole machine status, the deformation of the spindle end has reduced by 50.8%, and the maximum deformation of the workpiece end has reduced by 50.0%. Finally, a verification experiment of the relative position deviation between the end of the spindle and the worktable on the complete machine was carried out. The error of the simulation and experiment results was about 22%, which proves the effect of the optimization of the support position. [ABSTRACT FROM AUTHOR]

Purpose: The method using persulfate (PS) activation is effective for the remediation of organic pollutants contaminated soil. This study aims to evaluate the possibility of the application of green synthesized nanoscale zero valent iron (nZVI) activating PS for 1,2-dichlorobenzene (1,2-DCB) degradation in soil, investigate the effect of environmental factors such as nZVI dosage, PS concentration, and initial pH on 1,2-DCB removal efficiency and interpret the activation mechanism of nZVI for PS and degradation pathways of 1,2-DCB in soil. Materials and methods: The contaminated soil was added to a brown bottle of 250 mL and dispersed in deionized water with a volume ratio of 1:5. Specified concentration of PS and nZVI were added to the bottle to initiate the degradation reaction. The bottle was placed on a reciprocating shaker at room temperature of 25 ºC. Control experiments containing PS or nZVI were also performed under the same reaction conditions. At desired time intervals, the well-mixed suspension of 10 mL slurry was transferred into 50 mL glass vials and centrifuged. 20 mL organic solvent with a volumetric ratio of hexane to acetone of 1:1 was added to 50 mL glass vials after the supernatant was discarded. 1,2-DCB and its degradation intermediates were analyzed by Gas Chromatograph-Mass Spectrometer (GC-MS) through extract. Results and discussion: The maximum degradation efficiency of 97.3% with total organic carbon (TOC) removal of 61.3% for 1,2-DCB was achieved under the reaction conditions of initial 1,2-DCB concentration of 28.6 mg kg−1 in soil, 67.2 mg L−1 nZVI, 1.2 mmol L−1 PS and pH 7.5. Electron paramagnetic resonance (EPR) test indicated that SO4•− and •OH radicals were the dominant species being responsible for the degradation of 1,2-DCB. In addition, the GC-MS analysis showed that 3,4-dichlorophenol and o-chlorophenol were the primary intermediates, and the degradation pathways of 1,2-DCB were proposed subsequently. Conclusions: nZVI was successfully synthesized through green processes based on extracted tea polyphenol, and utilized for the remediation of 1,2-DCB contaminated soil by activated PS. The generated free radicals were responsible for the efficient degradation of 1,2-DCB with high TOC removal. The findings might have significant implications for the remediation of 1,2-DCB contaminated soil utilizing the nZVI/PS system. [ABSTRACT FROM AUTHOR]

Being a critical factor affecting the motion accuracy of precision machine tools, structural thermal elongation of precision ball screw unit is generally caused by the comprehensive influence from heat generations of screw-nut pair/bearings and time-varying ambient temperature. To resist 2 thermal disturbances above to guarantee precisely the original length of screw shaft, an active coolant control strategy is proposed in this paper. This strategy is based on a premise hypothesis: For the slender and long tubular structure of screw shaft, the screw shaft temperature is approximately equal to its recirculating coolant temperature. The reason is that the intensive forced coolant convection is capable of eliminating screw shaft temperature rises caused by friction heat generations and ambient air convections. Based on this premise, screw coolant temperature can be consistently controlled by an active strategy, further to correct the thermal elongation of screw shaft. It can be experimentally verified that the thermal variations of machine positioning accuracy caused by the active coolant control strategy are not more than 10 μm, which are lower than traditional strategy. Besides, based on detected structural temperatures of precision ball screw unit, the theoretical model above is further proved to be reliable by FE simulation method. [ABSTRACT FROM AUTHOR]

For thermal perception and control onto spindle bearings without spindle/bearing structural modifications for built-in thermal sensors, this paper proposes a thermal simulation speculation-based active coolant control strategy onto spindle bearings, for spindle accuracy guarantee. Firstly, numerical simulation technology is adopted to construct thermal collection of spindle bearings influenced by coolants. Secondly, this collection is utilized as the basis for ELM speculation modeling for bearing thermal behaviors. Eventually, the previous active coolant strategy is modified to be equipped with the model above for the speculation perception (according to the detectable spindle working parameters) and active control realization onto thermal behaviors of spindle bearings. It is verified by experiment and simulation that the thermal simulation speculation-based active coolant strategy is more advantageous than the previous strategy, in thermal stabilization and accuracy guarantee of motorized spindle unit. Besides, the power ratio between coolant heat dissipation and bearing heat generation is suggested to be 1.15:1 for a sufficient thermal balance of spindle bearings, which brings the design guidance onto cooling capacity/strategy of recirculation cooling equipment for motorized spindle unit. [ABSTRACT FROM AUTHOR]

Calculations of transient thermal loads/boundary conditions are crucial for accurate thermal simulations of motorized spindle unit with time-varying working parameters (such as rotation speed). By the ELM theory, this paper proposes a modeling and calculation method onto transient thermal loads/boundary conditions for spindle simulation, according to spindle temperature detections. Firstly, heat-fluid-solid coupling finite element model is established to simulate spindle thermal behaviors. Secondly, the relationship between the real-time simulated spindle temperatures and the corresponding transient thermal loads/boundary conditions are constructed by ELM method. With real-time experimental temperatures being the input vector, transient thermal loads/boundary conditions for simulation are calculated by the established ELM model. Ultimately, with the spindle operation with progressive rotation being an example, the reliability of the proposed method is verified by the agreement between simulated spindle temperatures and their detections. Furthermore, obtained transient thermal loads/boundary conditions and simulation results are utilized to analyze spindle pure heat absorption, for the guidance onto spindle coolant strategy optimization. [ABSTRACT FROM AUTHOR]

Error compensation is one of effective and economical means to improve the machining accuracy of machine tools. The measurement accuracy of kinematic errors has great impact on the accuracy of machine tool error modeling. Some measurement errors are inevitably generated due to the distortion of the slide table and the limit of local measuring stroke. To solve these problems, an improved machine tool volumetric error compensation method is proposed in this paper, based on linear and squareness error correction method. The linear errors, including position errors and straightness errors, are corrected by considering the distance effect between optical mirror groups and the surface of worktable. The squareness errors are corrected through modifying local squareness errors measured with double ball bar to global squareness errors, with the aid of straightness errors measured with multi-laser calibrator. Then volumetric errors are obtained based on multi-body system theory, and volumetric diagonal errors are measured with laser interferometer. It is illustrated that the bidirectional systematic deviation of positioning of four volumetric diagonals reduced about 81.3%, 35.2%, 29.2%, and 4.5% respectively by using this improved machine tool volumetric error compensation method, and it is of obvious advantages in contrast with traditional compensation method with direct measurement data. The improved error compensation method proposed in this paper has universal applicability and has great significance on machine tool accuracy improvement. [ABSTRACT FROM AUTHOR]

Introduction: Comparisons between brand and biosimilar basal insulin in hospitalized patients are lacking. We aimed to compare the efficacy and safety of brand insulin glargine vs. biosimilar insulin glargine in non-critical hospitalized patients with type 2 diabetes mellitus (T2DM).Methods: This retrospective study was conducted using the electronic medical records of 194,006 patients at the Qingdao Endocrine and Diabetes Hospital between January 2006 and December 2017. A total of 476 patients diagnosed with T2DM, hospitalized, and treated with subcutaneous insulin glargine were included. After propensity score matching (1:3), patients who received biosimilar insulin glargine (Basalin) (n = 34) were compared to a matched group of patients who received brand insulin glargine (Lantus) (n = 101). Outcome measures were changes in fasting blood glucose (FBG), the incidence of hypoglycemia, and insulin dose.Results: Compared to patients who received Basalin, patients who received Lantus achieved more reduction in FBG during insulin treatment (- 1.24 mmol/L vs. - 2.20 mmol/L; p = 0.04) and had a lower mean FBG at the end of treatment (8.20 mmol/L vs. 7.26 mmol/L; p = 0.12). Patients in Basalin and Lantus groups had a comparable mean daily dose of basal insulin at initiation (0.19 vs. 0.18 IU/kg; p = 0.30) and end of treatment (0.21 vs. 0.21 IU/kg; p = 0.99), and a similar duration of basal insulin treatment (16.4 vs. 15.3 days; p = 0.74). Hypoglycemia was infrequent in both Basalin and Lantus treatment (one vs. four patients, respectively; p = 1.00) and no severe hypoglycemic events were reported.Conclusion: In a non-critical hospital setting, subcutaneous treatment with Lantus brought significant FBG improvement without increased hypoglycemic risk. [ABSTRACT FROM AUTHOR]

Volumetric accuracy is susceptible to thermal gradient caused by internal heat source (IHS) and external heat source (EHS). A temperature-structure multi-step calculation method is presented to investigate the influences of EHSs on volumetric thermal errors of precision machine tools. The temperature and structure of the machine tool are simulated first, and then, the volumetric thermal errors are calculated using multi-body theory method. Simulations are completed to study the effects of different EHSs on a machine tool, and series of validating experiments are carried out to verify the modeling method. The test results in specific position and working condition revealed that EHSs contribute 53, 21, and 68% of thermal deviations in X, Y, and Z directions individually. It is illustrated that the EHS is an important factor affecting the volumetric accuracy of precision machine tools. The methods provided in this paper are valuable for machine tool designers to evaluate the EHS effects on volumetric thermal errors during designing process; furthermore, some insulating measures are suggested to improve the accuracy and accuracy stability of precision machine tools by reducing the EHS influences. [ABSTRACT FROM AUTHOR]

Geometric accuracy is crucially important for machine tools. Identification of geometric errors, especially position-dependent geometric errors, is still a challenging issue. This paper presents a systematic and fast approach to identify the geometric error components of a precision machine tool using double ball bar (DBB). The approach can be implemented in three steps: (1) polynomial based error modeling that relates the DBB radius error directly to the geometric error parameters of machine tool; (2) spatial measurement trajectory planning with a single installation of DBB in order to avoid producing extra setup errors; (3) error identification with regularization method that can solve the ill-posed identification problem effectively. Simulations and experiments show the accuracy and effectiveness of the proposed identification approach. The results of the DBB test show that, utilizing the proposed identification method, the roundness errors of the three circular paths in xy-, yz- and xz-plane are reduced from 27.3 μm, 20.7 μm and 24.1 μm to 9.2 μm, 12.3 μm and 7.8 μm, respectively, with error compensation. [ABSTRACT FROM AUTHOR]

Motorized spindle unit is the core component of a precision CNC machine tool. Its thermal errors perform generally serious disturbance onto the accuracy and accuracy stability of precision machining. Traditionally, the effectiveness of the compensation method for spindle thermal errors is restricted by machine freedom degrees. For this problem, this paper presents an active, differentiated, and intelligent control method onto spindle thermal behaviors, to realize comprehensive and accurate suppressions onto spindle thermal errors. Firstly, the mechanism of spindle heat generation/dissipation-structural temperature-thermal deformation error is analyzed. This modeling conveys that the constantly least spindle thermal errors can be realized by differentiated and active controls onto its structural thermal behaviors. Based on this principle, besides, the active control method is developed by a combination of extreme learning machine (ELM) and genetic algorithm (GA). The aim is to realize the general applicability of this active and intelligent control algorithm, for the spindle time-varying thermal behaviors. Consequently, the contrasting experiments clarify that the proposed active and intelligent control method can suppress accurately and synchronously all kinds of spindle thermal errors. It is significantly beneficial for the improvements of the accuracy and accuracy stability of motorized spindle units. [ABSTRACT FROM AUTHOR]

Conventional three-probe method of artifact roundness and spindle error measurements is subjected to the trouble of harmonic suppression, which is also mathematically complicated due to complex transformation processing. A novel three-probe method by solving system of multivariable equation (SSME) method is presented in this paper. The presented method simplifies the mathematical processing and has good robustness to the measurement angles which are difficult for conventional three-probe method. This paper gives mathematical models, detailed theoretical derivations, and numerical simulations. Selection criteria of the optimal measurement angle combinations can be determined in accordance with rank and condition number of the coefficient matrix. Then, to validate the feasibility and repeatability of the proposed method, experimental measurements are performed on a vertical machine tool spindle by using nanometer-resolution capacitive displacement sensors, high-precision indexing table, and professional data acquisition system. Artifact roundness error and spindle radial error are tested to validate separation accuracy by specialized instruments. The comparisons demonstrate that the proposed method has good feasibility and repeatability (the maximum deviations of spindle error and roundness error are 9.62 and 3.86%). SSME method, due to its simplicity in computation and the uniqueness of the solution provided, is more suitable to separate spindle radial error from the artifact roundness error. [ABSTRACT FROM AUTHOR]

Hydrostatic guideways are widely applied into precision and ultra-precision machine tools. Meanwhile, the oil film heat transfer causes thermal disturbance to the machine accuracy. Therefore, it is necessary to study the mechanism of the oil film heat transfer and the heat-transfer-reducing method to improve the machine accuracy. This paper describes a comprehensive thermal finite element (FE) simulation modeling method for the hydrostatic machine feed platform to study methods of reducing machine thermal errors. First of all, the generating heat power of viscous hydraulic oil flowing between parallel planes is calculated based on the Bernoulli equation. This calculation is then employed for the simulation load calculations for the closed hydrostatic guideways, which is adopted by the hydrostatic machine feed platform. Especially, in these load calculations, the changing of oil film thickness (resulted from external loads) and the changing of oil dynamic viscosity (influenced by its temperature) are taken into account. Based on these loads, thermal FE simulation modeling of the hydrostatic machine feed platform is completed to predict and analyze its thermal characteristics. The reliability of this simulation modeling method is verified by experiments. The studies demonstrate that the hydrostatic machine thermal error degree is determined by the oil film heat transfer scale, and this scale is mainly influenced by the relative oil supply temperature to ambient temperature (quantitative comparison of oil supply temperature and ambient temperature). Furthermore, the reduction of the absolute value of this relative oil supply temperature can reduce the oil film heat transfer scale and improve the machine accuracy. [ABSTRACT FROM AUTHOR]

The motion track of belt spindle is important for the radial error of belt spindle. An analytical modeling method for the motion track of belt spindle under the combined effects of bending moment-torque-thermal deformation is proposed in this paper. Three running phases of belt spindle have been analyzed and modeled: the start-up phase with leaping change due to the change in force and bending moment, the accelerating phase with axis deflection, and the constant speed phase with axis regression because of the combined effects of bending moment-torque-thermal deformation. The simulation and test were completed on the belt spindle of SKVM850 machine tool, which illustrates the variation law of the radial error of belt spindle during the whole running phases. [ABSTRACT FROM AUTHOR]

Aims: To examine and compare health-related quality of life (HRQoL) in people with previously known diabetes, new screen-detected asymptomatic diabetes and people without diabetes. Methods: HRQoL of 4,613 individuals who participated in a population-based cross-sectional diabetes survey in Qingdao, China, in 2009, was assessed using the 15D instrument. A Tobit regression model to estimate the effects of diabetes on HRQoL separate from effects of other health determinants was constructed. Results: Among the surveyed population, 220 (4.8 %) individuals had previously known diabetes and 531 (11.5 %) individuals had new screen-detected diabetes, defined by fasting plasma glucose ≥7.0 mmol/l and/or 2-h plasma glucose ≥11.1 mmol/l. The age-, gender-, and BMI-adjusted mean 15D score of people without diabetes, with new screen-detected diabetes, and previously known diabetes was 0.975, 0.975, and 0.964, respectively, for urban and 0.971, 0.972, and 0.960, respectively, for rural participants. HRQoL overall and on all the dimensions ( p < 0.05) except for hearing, eating, and speech was worse in the people with previously known diabetes compared to those with new screen-detected diabetes and those without diabetes. Compared to people without diabetes, people with new screen-detected diabetes were worse off on the dimension of usual activities ( p < 0.05). After adjusting for comorbid diseases and other confounders, the impact of diabetes on reduced HRQoL was diminished. Conclusion: Health-related quality of life was impaired in people with previously known diabetes who had co-morbid conditions, but was largely unaltered in people with newly detected asymptomatic diabetes as compared to people without diabetes. [ABSTRACT FROM AUTHOR]

Updating parameters according to the driving rate of input, the rate-dependent Prandtl-Ishlinskii (PI) model is widely used in hysteresis modeling and compensation. In order to improve the modeling accuracy, two PI models identified at low and high driving rates separately are incorporated through a combination law. For the piezo-driven flexure-based mechanism, the very low damping ratio makes it easy to excite the structural vibration. As a result, the measured hysteresis loop is greatly distorted and the modeling accuracy of the identified PI model is significantly affected. In this paper, a novel time-efficient parameter identification method which utilizes the superimposed sinusoidal signals as the control input is proposed. This method effectively avoids the excitation of the structural vibration. In addition, as the driving rate of the superimposed sinusoidal signals covers a wide range, all the coefficients required for modeling the rate-dependence can be identified through only one set of experimental data. Hysteresis modeling and trajectory tracking experiments were performed on a 2-DOF piezo-driven flexure-based mechanism. The experimental results show that the combined hysteresis model maintains the modeling accuracy over the entire working range of the flexure-based mechanism. The mechanism's hysteresis is significantly suppressed by the use of the inverse PI model as the feedforward controller; and better result is achieved when a feedback loop is also incorporated. The tracking performance of the flexure-based mechanism is greatly improved. [ABSTRACT FROM AUTHOR]

In this paper, eddy current sensors and thermocouple sensors were employed to measure the thermal field and thermal deformation of a spindle of a telescopic CNC boring-milling machine tool, respectively. A linear regression method was proposed to establish the thermal error model. Furthermore, two compensation methods were implemented based on the SIEMENS 840D system by using the feed shaft of z direction and telescopic spindle respectively. Experimental results showed that the thermal error could be reduced by 73.79% when using the second compensation method, and the thermal error could be eliminated by using the two compensation methods effectively. [ABSTRACT FROM AUTHOR]

Summary. Let P be a block p-cyclic stochastic matrix with stationary distribution ${\bf \pi}^{\rm T}$ , which is partitioned conformally in the form $({\bf \pi}_1^{\rm T},\ldots,{\bf \pi}_p^{\rm T})$ . This paper establishes the relative error bound for ${\bf \pi}_i^{\rm T}$ when each block of P gets a small relative perturbation. [ABSTRACT FROM AUTHOR]

Composite of nanoscale Zero Valent Iron (nZVI) loaded on Biochar (BC) was prepared and characterized as hydrogen peroxide (H2O2) activator for the degradation of trichloroethylene (TCE). nZVI is homogeneously loaded on lamellarly structured BC surfaces to form nZVI/BC with specific surface area (SBET) of 184.91 m2 g−1, which can efficiently activate H2O2 to achieve TCE degradation efficiency of 98.9% with TOC removal of 78.2% within 30 min under the conditions of 0.10 mmol L−1 TCE, 1.13 g L−1 nZVI/BC and 1.50 mmol L−1 H2O2. Test results from the Electron Spin Resonance (ESR) measurement and coumarin based fluorescent probe technology indicated that ∙OH radicals were the dominant species responsible for the degradation of TCE within the nZVI/BC-H2O2 system. Activation mechanism of the redox action of Fe2+/Fe3+ generated under both aerobic and anaerobic conditions from nZVI and single electron transfer process from BC surface bound C-OH to H2O2 promoted decomposition of H2O2 into ∙OH radicals was proposed. [ABSTRACT FROM AUTHOR]

A letter to the editor related to the effect of MYH9 disorder, autosomal dominant disorders is presented.