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Optimizing the installation parameters of photovoltaic panels in a photovoltaic array to reduce dust accumulation, thereby enhancing their power generation, is a crucial research topic in the construction of solar power stations in desert regions. Utilizing a series of wind tunnel experiments on a photovoltaic array comprising four equally sized panels, this study assessed how variations in tilt angle, mounting height, spacing, and incoming flow direction influence both the accumulation mass of dust and the particle size distribution in a photovoltaic array. The results indicate that the dust accumulation on the first panel exponential growth with increasing tilt angle, incoming flow angles, and height, while subsequent panels displayed a trend of initial increase followed by a decrease, with a maximum increasing ratio achieved at specific installation configurations, the difference of dust mass on each panel can even be several times. Notably, when the spacing between panels exceeds twice the panel height, the mutual influence on dust deposition becomes negligible, providing a quantifiable threshold for optimal panel spacing. Additionally, significant differences exist in the particle size characteristics of dust in the panel of the array, influenced by the installation parameters of panels and the direction of the incoming flow. This research not only enhances the understanding of dust accumulation in solar energy systems but also offers practical recommendations for optimizing installation strategies, thereby improving the economic viability of solar power stations, particularly in desert regions.

Due to its simple structure and good deployable characteristics, scissor-like structure (SLS) is widely used in many fields, such as mechanical engineering, structure engineering, and aerospace engineering. Because of its inherent structural characteristics, a SLS can possess superior nonlinearities both in equivalent stiffness and damping only with linear component. It also has high loading capacity and excellent equilibrium stability. Thus, it is promising as a vibration isolator. Based on recent findings, a theoretical study is herein executed to build up a universal stiffness model of full types of SLS (including 6 assembly types), considering mass of scissor arm, Coulomb and viscous friction forces in joint parts. Plus more, perturbation method (PM) and average method (AM) are applied to investigate vibration isolation performances of SLS with different assembly types and installation parameters and to compare them with known quasi-zero-stiffness vibration isolators in the literature. Finally, a simulation is done to testify the presented findings and to compare them with former studies. It is shown that: without changing its overall structure and outside dimensions, a SLS vibration isolator can have significantly different nonlinear stiffness for specific nonlinear characteristics only through adjusting assembly type, installation parameters, and initial deformation of its linear component. Since allowable workspace of a vibration isolator is always limited by isolation object and its surrounding structure, this finding indicates a new way to design and modify vibration isolation performance of a system. It will greatly expand application of SLS in vibration isolation.

The novel approach of the study is implementing the installation procedure of fly ash (FA) replaced cement deep mixing (DM) columns to field cases aiming at managing FA waste and reducing cement utilization. FA replaced cement DM columns (diameter of 30 cm and length of 80 cm) were installed on clayey soils using a laboratory type DM machine. The effect of installation parameters such as the binder dosage, FA replacement ratio, superplasticizer content, water/binder ratio, and the liquidity index (LI) of the soil on column performance was investigated. The design of experiments and optimization process were conducted using the Taguchi method, S/N and ANOVA analyses, and the desirability function method. Observations have shown that the mixing time required for a homogeneously mixed column depends on the LI of the soil and the volume ratio (VR) of the slurry. A key parameter (LI∙VR) is defined to decide the minimum number of the mixing process. The blade rotation number should be minimum of 252 rev/m to obtain a homogeneous soil-slurry mixture. The highest strength of the column was obtained when LI of fresh soilcrete (LI mix ) is 1.25∙LI. Optimum installation parameters were determined as binder dosage of 425 kg/m 3 , FA replacement ratio is 40%, superplasticizer content is 3%, water/binder ratio is 0.8, and LI of the untreated soil is 1. In the optimum design, the mixing efficiency of the soil-slurry mixture increased and the best column performance was obtained. In addition, cement utilization and binder cost decrease 40% and 33%, respectively, in FA-replaced cement DM columns. SEM images prove the increase in column performance due to the cementation products (CSH and CAH gels) formed in the microstructure of the column.

In this study, the installation parameters of the deep mixing (DM) column were optimized to manufacture a homogeneously mixed column and to reduce variability in the strength of the column. DM columns, 30 cm in diameter and 70 cm in length, were manufactured on clayey soils of different consistencies using a DM machine and slurry batch plant in the laboratory. The strength of DM columns and soil improvement ratio were investigated using installation parameters such as the cement dosage, the rotational speed of the mixing blades, the nozzle diameter, and the liquidity index of the soil. The design of experiments was conducted using the Taguchi method with a 4-parameter and 3-level L9 orthogonal array table. According to the observations during the installation of columns, the mixing time required to obtain a homogeneous soil-slurry mixture depended on the liquidity index of the fresh soilcrete. In addition, an interface layer, which is stiffer than the unimproved clay, was observed between the column and the unimproved soil. The thickness of the interface layer is 3–8% of the column diameter. Statistical evaluation was performed with S/N (signal-to-noise) and variance (ANOVA) analyses using the 28-day core strength of the columns. Optimum installation parameters were determined as cement dosage of 325 kg/m 3 , the rotation speed of the mixing blade is 80 rpm, nozzle diameter is 3 mm, and liquidity index of the soil is 1. The coefficient of variance for strength values decreased from 0.29 to 0.1 when the column was constructed with optimum installation parameters.

Supplying homogenous and suitable airflow schemes were explored in Chinese solar greenhouses, which had a positive impact on the crop yield and quality. This paper provided a multifunctional fan–coil unit system (FCU) to assist in circulating air. This system could collect the surplus heat of daytime air and release it to heat the greenhouse at nighttime. However, the main problem to be faced was the nonuniform airflow distributions. Thus, this paper aimed to optimize and analyze the placement strategy of the FCU system for a Chinese solar greenhouse using the numerical methodology. The computational fluid dynamics model was constructed to evaluate the effect of the FCU system on the airflow field and to uphold its validation. The complex structure of the FCU system was simplified to a fan model by fitting the pressure jump and the air velocity to enhance the practicality of the simulation model. Finally, the coefficient of variation was used to optimize four parameters: the tilt angle, swing angle, height above the ground, and shape of the outlet baffle. The effective disturbance velocity percentage was proposed as the evaluation index to improve the turbulence characteristics. The mean absolute error (MAE) between the measured and simulated values of the air velocity for the two planes was 0.06 m/s and 0.09 m/s, and the root mean square error (RMSE) was 0.08 m/s and 0.11 m/s. The simulated results showed that the coefficient of variation before optimization was 0.76, and the effective disturbance velocity percentages of the planes at 0.7 m and 1.0 m from the ground were 42.73% and 41.02%, respectively. After optimization, the coefficient of variation was reduced to 0.33, and the effective disturbance velocity percentages of the two planes increased to 58.68% and 43.73%, respectively. These results significantly improved the uniformity of the interior airflow field. This paper provides a reference for the design and installation of the FCU system.

The profile accuracy of screw rotors plays a vital role in stabilizing the meshing operation between mated rotors. Such stability can minimize the vibration and noise, as well as improve the sealing performance and wear resistance. This is the main reason why form grinding is extensively applied as a finishing process to maintain high screw rotor profile accuracy. Since the installation parameters for form grinding wheels affect both the grinding wheel profile accuracy and grinding performance, it is essential to obtain reasonable installation parameters to guarantee the high precision and good grinding performance of form grinding wheels. In this paper, a novel optimization design method for form grinding wheels for screw rotors has been proposed. For the first time, the relationship between the grinding wheel installation parameters and profile accuracy is established to evaluate the grinding performance. A parameterized program has been designed based on space engagement theory. The characteristics of the contact line and profile features of form grinding wheels under different installation parameters have been investigated. Then, the proposed method was employed to select the correct range of installation parameters. To validate the proposed method, a set of experiments, including the manufacture and measurement of several screw rotors, was carried out. The results reveal that the precision of the screw profile is significantly improved compared with the empirical method, thus showing the effectiveness of the proposed method.

Owing to the vibrations and thermal shocks that arise during the launch and orbit penetration process, the on-orbit installation parameters of multiple star sensors are different from the on-ground measured parameters, causing inconsistencies in the attitude determinations from different combination modes and seriously affecting the geometric accuracy of high-resolution optical remote sensing images. This study presents an on-orbit calibration approach for the installation parameters of a multiple star sensors system using ground control points (GCPs). Based on the on-ground installation parameters of the optical axes of conventional star sensors, a fiducial coordinate system is proposed as the calibration coordinate system. The installation parameters of the conventional star sensors are calibrated using the statistical characteristics of angles between axes of the star sensor and three fiducial vectors in the J2000 celestial coordinate system. Based on the GCPs, the relative fiducial parameters are calculated, and the installation parameter of unconventional star sensor is then calibrated with the relative fiducial parameters and statistical characteristics of angles. It can be used for high-resolution optical remote sensing satellite measuring with only two star sensors to unify the fiducial coordinate system. The proposed method is tested using simulated data and on-orbit measurement data. The results demonstrate that the proposed method can calibrate the optical axis of the star sensor without the restriction of the accuracy of horizontal axis. Moreover, the star sensor with a large installation angle error can be calibrated well using the proposed approach. The results of attitude determinations from different star sensor combination modes are consistent, and the geometric accuracy of the remote sensing images is significantly improved.

In the course of experimental studies, the method of operational setting of the parameters of mass crystallization of gas hydrate in reservoir systems that have not reached a state of equilibrium is substantiated. The technique is implemented by setting the process parameters at the moment of visual identification of the solid phase of the gas hydrate on the interphase surface of the gas bubble or the place of its exit from the liquid. The requirements for the construction of the reactor unit of the laboratory installation for the implementation of this technique are substantiated. A laboratory installation has been developed and implemented. The results of test studies are presented and the features of identification of the solid phase of gas hydrate at the moment of the beginning of its mass crystallization are demonstrated. The proposed method allows you to quickly obtain objective information about the possible behavior of this system in the case of intensive changes in parameters in non-equilibrium conditions.

With the development of industrial automation, articulated robots have gradually replaced labor in the field of bolt installation. Although the installation efficiency has been improved, installation defects may still occur. Bolt installation defects can considerably affect the mechanical properties of structures and even lead to safety accidents. Therefore, in order to ensure the success rate of bolt assembly, an efficient and timely detection method of incorrect or missing assembly is needed. At present, the automatic detection of bolt installation defects mainly depends on a single type of sensor, which is prone to mis-inspection. Visual sensors can identify the incorrect or missing installation of bolts, but it cannot detect torque defects. Torque sensors can only be judged according to the torque and angel information, but cannot accurately identify the incorrect or missing installation of bolts. To solve this problem, a detection method of bolt installation defects based on multiple sensors is proposed. The trained YOLO (You Only Look Once) v3 network is used to judge the images collected by the visual sensor, and the recognition rate of visual detection is up to 99.75%, and the average confidence of the output is 0.947. The detection speed is 48 FPS, which meets the real-time requirement. At the same time, torque and angle sensors are used to judge the torque defects and whether bolts have slipped. Combined with the multi-sensor judgment results, this method can effectively identify defects such as missing bolts and sliding teeth. Finally, this paper carried out experiments to identify bolt installation defects such as incorrect, missing torque defects, and bolt slips. At this time, the traditional detection method based on a single type of sensor cannot be effectively identified, and the detection method based on multiple sensors can be accurately identified.

Large deformations often occur during and after the construction of deep roadways, particularly in fractured hard rock. With persistent deformation, there may be mechanistically unexplained, repeated failure phenomena—they are difficult problems to analyse and address. One strategy is to analyse the failure characteristics of roadways and internal cracking characteristics of the surrounding rock which can be analysed with a digital borehole televiewer and three-dimensional laser scanning equipment. Here, we used this approach combined with research on geostress, joint information, and mechanical properties of rock to reveal the preliminary large deformation mechanism of deep fractured roadways. Based on a cracking-restraint method for engineering design, a control technique is proposed to prevent and control large deformations. The depth and degree of cracking are considered to design parameters and determine the appropriate installation time of the support system. To test this approach, the proposed control technique was applied to a roadway project more than 700 meters deep. The monitoring results demonstrated that this control strategy effectively restrained the cracking of surrounding rocks, improved the quality index of the rock mass, and reduced surface displacement. In addition, due to the improved deformation capacity of the bolt structure, an anti-deformation and energy-absorbing bolt can bear large deformations, preventing premature bolt failures in mining environments.