Bariatric surgery and exercise: A pilot study on postural stability in obese individuals

This study aimed to analyze the changes in postural stability of individuals with obesity after bariatric surgery, and the effect of three months of regular exercise on the static postural stability. Twenty-two subjects (7 females and 15 males) aged 31 to 68 years (Body mass index 35–55 kg.m-2) completed the study. Participants were divided into two groups: one group participated in an exercise program after the bariatric surgery (n = 10; age 48.9 ± 7.5 years; Body mass index 42 ± 5.6 kg.m-2) while the second group did not exercise at all after bariatric surgery (n = 12; age 44.7 ± 13.6 years, Body mass index 42.6 ± 6.0 kg.m-2). Static postural stability was measured using a Tekscan MobileMat pressure plate before and 4 months after the bariatric surgery. The exercise program included exercising three times a week including: one hour of strengthening, one hour of aerobic group exercise and at least one session of individual exercise at home. There were no significant differences in Center of force sway, Center of force ranges and average speed before and 4 months after bariatric surgery. Also, no effect of exercise was found. Post-pre differences of some parameters were negatively related to age (r from—0.46 to—0.72). Further studies are needed to explore this topic in depth.

Faster R-CNN Algorithm Based Relay Protection Platen State Identification Method

Currently, the check of the relay protection pressure plate’s throw-out status is mainly carried out manually, due to the extremely large number of decompression plates, manual methods can cause detection errors due to fatigue. This paper proposes the processing of relay protection pressure plate photographs by using image processing techniques, the Faster R-CNN image recognition algorithm uses the feature of generating detection frames directly using RPN to identify the platen throwback status of the processed platen images, greatly improving the speed and accuracy of the detection frame generation. The experimental results show that, the method proposed in this paper effectively solves the problem of errors arising from manual verification checks of platen throwbacks, reduced workload for substation staff, the platen recognition rate can be over 98% correct.

Modeling and Dynamics Analysis of a Dual-Mass Flywheel with the Conformal Contact Action of Friction Damping Ring and Pressure Plate

To study the nonlinear dynamic characteristics of the dual-mass flywheel (DMF) under the conformal contact action between the friction damping ring and primary flywheel pressure plate, the contact action model is established and analyzed based on Winkler model. Through analysis and calculation, the contact deformation, contact pressure at different contact positions, and equivalent torsional contact stiffness are obtained. The nonlinear dynamic analysis model of three-degree-of-freedom (3DOF) which takes the conformal contact into account and two-degree-of-freedom (2DOF) without considering conformal contact is established. The approximate analytical solution of the nonlinear frequency characteristics of the system at steady state is derived. By comparing with the results obtained from numerical method, the theoretical analysis process is proved to be valid. And it is found that the overall amplitude and angular displacement transmissibility of the 3DOF model are smaller than the 2DOF model, especially at resonance frequency. The effects of the friction damping ring moment inertia, stiffness of DMF, and axial friction torque on the frequency characteristics of system and angular displacement transmissibility are analyzed. The forced vibration response analysis of the 3DOF model is conducted, through which the torsional angle variations of the primary flywheel, friction damping ring, and secondary flywheel with time are obtained. The results show that the amplitude of the secondary flywheel is much smaller than that of the primary flywheel, indicating that the DMF has prominent damping performance.

Design and Experiment of the Buckwheat Hill-Drop Planter Hole Forming Device

The hole forming device is an important element of the buckwheat hill-drop planter, and its design level directly affects the seeding quality of the hill-drop planter. A hole forming device with a duckbill structure is widely used in hill-drop planters for wheat, cotton, peanuts, etc. According to the requirements of buckwheat seeding operations, this study designs the components of the duckbill hole forming device. It is determined that the duckbill upper jaw length is 65 mm, the duckbills number is 10, the pressure plate on the spring side length is 90 mm, the duckbill opening size is 8.79 mm, and the duckbill effective opening time is 0.1 s. Through co-simulation analysis of discrete element software EDEM (DEM-Solutions, Edinburgh, United Kingdom) and multi-body dynamics software RecurDyn (FunctionBay, Inc., Seongnam-si, South Korea), it is measured that when the pressure plate on the spring side is directly below the rotation axis of the dibber wheel, the spring compression is 33.3 mm, the pressure on the pressure plate is 95–102.6 N, and the contact time of a single duckbill with the soil is 0.2 s at a speed of 40 r/min. Based on the results of the design and simulation analysis, the large end diameter, small end diameter, original length and wire diameter of the duckbill spring are 36 mm, 26 mm, 60 mm, and 1.8 mm, respectively. An experimental bench for the seeding wheel of a buckwheat hill-drop planter was built, and three wire diameter duckbill springs of 1.6 mm, 1.8 mm and 2.0 mm were tested to verify the simulation and calculation results. The experimental results show that the optimal wire diameter of the duckbill spring is 1.8 mm. Finally, a single factor experiment of the dibber wheel rotation speed was carried out. The experimental results show that when the rotation speed of the dibber wheel is 40–65 r/min, the seeding qualification rate, seeding void hole rate and seeding damage rate of the buckwheat hill-drop planter are ≥85.3%, 0, and <0.3%, respectively. This study provides a basis and reference for the hole forming device design of a buckwheat hill-drop planter.

Torque capacity of multidisc wet clutch with reference to friction occurrence on its spline connections

In this article developed mathematical model that includes friction occurrence on spline connections is presented. The work also contains results of experimental research on torque capacity of multidisc wet clutch. These results are expressed as a function of contact pressure for different number of friction surfaces. Due to increased interest in research concerning multidisc wet clutches it is essential to determine impact of friction on fit connections on transmitted torque. Analytical calculations that include both known loss coefficient and assumed lack of friction on fit connections are compared to results of experiments. The paper contains detailed description of test stand and methodology of experiment. As a result of conducted tests it was found that correction coefficients known from literature are highly inaccurate. Measured values of torque indicate that transmitted torque reach significantly higher values. It was also revealed that after slippage appeared, the pressure plate usually moved in the direction of exerted clamping force, but movement in reversed direction also took place for some experiments. While movement corresponding to clamping force reached ca. 0.08 mm, in opposite direction amounted to 0.02 mm. Furthermore, studies presented that lapping of adjacent friction surfaces greatly affects differences between respective results obtained for a specific experiment.

Experimental Research of Paperboard Cutting in Die Cutting Press with the Screw–Nut Transmission of Drive Mechanism of a Movable Pressure Plate

This paper reports experimental research of torques during paperboard cutting in the die cutting press with the screw–nut transmission in the drive mechanism of the movable pressure plate. The purpose of the study is to substantiate the practical implementation of the pressure plate drive mechanism with the use of screw–nut transmission for the production of cartons of paperboard blanks. The manufactured experimental bench for the research of paperboard blanks provides the possibility of getting dependencies of loads on different parameters of the die cutting process. The developed method of the experimental research envisages the use of the strain gauge method and the wireless module for data measurement and software for its processing that allow getting trustworthy results with minimum faults. As a result of experimental research studies, the impact of paperboard thickness and cutting velocity on torque values has been established. Results of experimental research allow getting trustworthy and systematised information about torque values depending on the thickness of the paperboard, the paperboard fibre direction and pressure plate displacement velocity. It is established that torque values on drive shaft during die cutting of paperboard blanks made of folding boxboard with thickness that lay in range of 0.3–0.7 mm. Experimental research studies show the impact of rotation speed of a drive shaft of the pressure plate drive mechanism on the torque value. The article shows the workability of the designed device with screw–nut transmission in the drive mechanism of a movable pressure plate.

SWCC of Calcareous Silty Sand Under Different Fines Contents and dry Densities

Investigating the soil-water characteristics of calcareous soil has a great significance for preventing geological disasters on island-reefs as well as maintaining the foundation stability of hydraulic-filled island-reefs. In this study, calcareous silty sands with different fines contents and dry densities were studied to reveal their effects on the soil-water characteristics of calcareous soil on hydraulic-filled island-reefs. The soil-water characteristic curve (SWCC) of the calcareous silty sand was measured using a pressure plate apparatus. Taking into account the porous meso-structure, the effects of fines content and dry density on the SWCC of calcareous silty sand were analyzed, and the applicability of existing SWCC models to calcareous silty sand was verified. A SWCC model suitable for assessing soil-water characteristic of calcareous silty sand was proposed. Results of this study provide some reference for quantifying the water-holding capacity of calcareous silty sand.

Simulation training technique for performing percutaneous endoscopic gastrostomy

The OBJECTIVE was to create a simulator for practicing manual skills of performing percutaneous endoscopic gastrostomy (PEG).METHODS AND MATERIALS. A patient simulator has been developed. It has a mouth, oropharynx, removable esophagus, stomach, and anterior abdominal wall that allows performing all stages of the operation. To objectify tension force of the gastrostomy tube during fixation and transmitting the proper manual sensations, a measuring device – bezmen was used. Initially, we used a single-use gastrostomy kit Freka PEG, FR 20 for the simulation. It increased the cost of the simulation. Therefore, instead of disposable kits, the Pezzer catheter No. 24 with a developed metal coneshaped tip was used as a gastrostomy tube (patent RU 2669483, 11.10.2018). Simulation was performed with reusable surgical instruments. At the final stage, an additional external pressure plate and a connector with a cover were used.RESULTS. The developed method of simulation training for PEG imposition allows performing all stages of endoscopic gastrostomy imposition. The simplicity of manufacturing and the possibility of replacing worn elements allows multiple implementation of the method. Using reusable instruments and a Pezzer catheter with a designed reusable tip increases the cost-effectiveness of training. The use of a measuring device allows to convey the necessary sensations of tension of the gastrostomy tube during fixation with an external pressure plate, corresponding to the sensations in real clinical simulation.CONCLUSION. The developed method of training for PEG imposition with the simulator allows to effectively work out manual skills and reduce the risk of iatrogenic complications during surgery on the patient.