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The paper deals with the application of spectrophotometric method and the sensor for determination of contaminating hydrocarbon impurity presence in waste water. The sensor is designed on the basis of modern element base. For measurement accuracy increase it has computer processing of analysis results for the absorption spectra of liquid (water) media in the ultraviolet wavelength range. The proposed sensor and computer program enabled the study of hydrocarbon impurity presence in the water that is an important factor for continuous monitoring of the environment. The absorption spectra of gasoline, diesel fuel, synthetic motor oil, fuel oil, natural oil are given as the most frequently present as impurities in the water, measured on an automated spectrophotometric sensor model. The use of modern small-sized elements makes it possible to design a small-sized highly sensitive sensor for express analysis of the water quality.

To address the poor seeding uniformity and low stability of traditional seeders when sowing small, lightweight forage alfalfa seeds, this paper conducts a theoretical analysis of the key components of an air-blown alfalfa seeding mechanism. The Fluent–Rocky coupling simulation method is employed to investigate the effects of the structural parameters of the three-way pipe (contraction angle α and throat height h) on seeding performance. To obtain the optimal parameter combination, a two-factor, three-level orthogonal bench test was designed with throat height and contraction angle as independent variables. The results showed that when the contraction angle α was 20° and the throat height h was 18 mm, the coefficient of variation for seeding stability was 2.56%. Field validation tests indicated that under these parameter conditions, the average airflow velocity at the outlet of the seeding tube was 13.21 m/s, and the coefficient of variation for seeding stability was 3.09%, demonstrating good overall machine performance that met the requirements for alfalfa seeding operations. This study can provide a theoretical basis and technical reference for the optimal design of pneumatic seeding equipment for forage grass.

Spacecraft is severely limited in weight and volume, resulting in a small bending radius of the fiber coil used by IFOG (Interference Fiber Optic Gyroscope). The fiber coil has such a size that the influence of bending on fiber birefringence cannot be ignored. In this paper, we research magnetic-induced errors of small-sized IFOG working in low orbit space. Firstly, we use the Jones matrix to analyze the effects of radial magnetic field and axial magnetic field on IFOG. Secondly, we establish a three-dimensional model for the radial magnetic-induced errors and magnetic-induced errors of minor radius fiber coil. Using the finite element method, we analyze the magnetic-induced error between different levels of the fiber coil. Combined with the birefringence distribution of the minor radius fiber coil, an accurate three-dimensional magnetic-induced error model is established. Thirdly, in the experiment, we design the magnetic-induced error test platform that includes the Fluke standard current source, transconductance amplifier, and Helmholtz coil. The experimental results show that, compared with the traditional calculation method, the three-dimensional magnetic-induced error model reduces the RMSE (Root Mean Square Error) of the radial magnetic field by 56.9% and the RMSE of the axial magnetic field by 35.7%, respectively.

Small-sized inner intersecting holes are a common structure for large engine nozzles, hydraulic valves, and other parts. In order to ensure the uniform and stable fluid state in the intersecting hole, it is necessary to process the fillet at the intersecting line and accurately control the fillet radius. Limited by the structure and size, the rounding of the small-sized inner intersecting hole is a technical problem, and the traditional machining methods have problems, in terms of efficiency and accuracy. In order to solve this problem, electrochemical machining technology was applied to the rounding of small-sized inner intersecting holes. According to the structure of inner intersecting holes, an electrochemical rounding processing scheme with built-in fixed cathode was designed. The electric field distribution of different cathode shapes was analyzed using finite element method software. The influence of processing voltage and processing time on the current density distribution was studied for different cathode shapes, to determine the most reasonable cathode shape. Taking the inner intersecting hole with a diameter of 2 mm as the research object, and according to the analysis of the influence of processing voltage on the processing effect, a suitable control factor for controlling the rounding was processing time, and the optimal processing voltage was obtained. The formulas of fillet radius and processing time were obtained by regression analysis and verified using machining examples. The results provide a feasible method for the accurate and controllable machining of small-sized inner intersecting hole rounding.

Hill’48 yield function has been widely used to describe the anisotropic behaviors of material in FE simulation of tube and sheet metal forming process. To obtain the material behaviors of small-sized H96 brass extrusion double-ridged rectangular tube (DRRT) in bending process, an inverse method combining response surface method and three-point bending was proposed to identify the parameters of Hill’48 yield function. It was found that comparing with Hill’48 yield function only considering the normal anisotropy and Mises yield function, Hill’48 yield function with the identified parameters performs the best in reproducing the material behavior of H96 brass DRRT in three-point bending process. And then Hill’48 yield function with the identified parameters was also adopted in the FE simulations of rotary draw bending of DRRT. It was observed that the prediction accuracy of cross sectional deformation of DRRT in rotary bending process was improved effectively by using Hill’48 yield function with the identified parameters. This proves that the proposed inverse method is suitable to the real forming process.

The objective of this investigation is to clearly understand the aerodynamic characteristics of a small-sized wind turbine of NREL Phase VI, operating with a stall-regulated method using CFD code. Based on this, it is possible to provide turbine designers with the aerodynamic design data to increase efficiency and improve performance in the design phase of future small-sized wind turbine blades. Moreover, a comparison was made between experimental datasets, in order to verify the reliability and validity of the analysis results. The first height in the normal direction from the surface of a rotor blade is about 0.2 mm, and the average value of y + is about 7 at 7 m/s. The domain is chosen to consist of only two hexahedral mesh regions, namely the interior region, including the wind turbine blade, and the external region excluding the rectangle. The total cell number of the numerical grid is about N g = 3.0 × 10 6 . Five different inflow velocities, in the range V in = 7.0−25.1 m/s, are used for the rotor blade calculations. The calculated power coefficient is about 0.35 at a TSR of 5.41, corresponding to 7 m/s, and showed considerably good agreement with the experimental measurements, to within 0.08%. It was observed that the 3-D stall begins to generate near the blade root at a wind speed of 7 m/s. Therefore, root design approaches considering the appropriate selection of the angle of attack and the thickness are very important in order to generate the stall on the blade root. Through a clear understanding of aerodynamic characteristics of a small-sized NREL Phase VI wind turbine, it is expected that this useful aerodynamic data will be made available to designers as guidance in designing stall-regulated wind turbine blades in the development phase of small-sized wind turbine systems in the future.

The software package for dimensional precision processing of multilayer reflecting X-ray optical elements using small-sized tools is described. The program structure is described, which includes the following main components: database, required shape setting unit, specific workpiece setting unit, processing path calculation unit, and G-code generator for a numerical control machine. The feature of the presented work is the use of low-cost equipment, first of all measurement instrumentation. This necessitated the development of specialized programs of surface reconstruction. The features of three-dimensional surface reconstruction by the results of individual linear scans using a coordinate measuring machine were analyzed. An important element of reconstruction is noise removal. Noise classification was performed. For each noise type, a specific suppression algorithm was developed and implemented in the program.