Separation characteristics and structure optimization of double spherical tangent double-field coupling demulsifier

The demulsification and dewatering of the W/O emulsion are widely used in petrochemical industry, oilfield exploitation, and resource and environmental engineering. However, efficiently treating emulsion via traditional single methods. In this study, a new double-field coupling demulsification and dewatering device is proposed, where the conical structure of the device is double spherical tangential type. The numerical model for double-field coupling is established, especially, the population balance model (PBM) is used to simulate the coalescence and breakup of dispersed droplets under the double-field coupling action. And the effects of three conical structures on the internal flow and separation efficiency are analyzed. Results show that the conical structure has a significant effect on the coalescence of droplets, especially the double spherical tangential cone is more conducive for improving the coalescence ability of small droplets and improving the separation efficiency of the device. After optimization, the optimal R value of the double spherical tangential coupling device is 300 mm, and the separation efficiency can be up to 96.32%, which is 6.13% higher than the separation efficiency of the straight double-cone coupling device.

Two-photon-polymerization enabled and enhanced multi-channel fibre switch

This article discusses the fabrication and performance of a multi-channel fibre switch, consisting of 19 single-mode fibres, with enhanced coupling efficiency due to micro-optics, directly printed via two-photon-polymerization on the end-face of each fibre. The use of high-resolution two-photon-polymerization not only allows the enhancement of the coupling efficiency with respect to the coupling device in use but likewise offers great freedom in the arrangement of the used fibres. This letter gives a thorough explanation of the fabrication method as well as the optical simulations for the lenses on the fibre assembly.

ESTIMATION OF THE EFFICIENCY OF THE LUBRICATION OF THE WORKING SURFACES OF THE SADDLE-COUPLING DEVICE OF THE FOREST TRUCK

The importance of the need for further constructive improvement of fifth-wheel couplings of timber tractors with semi-trailers has been substantiated. The main operational factors arising during the movement of a timber tractor with a semitrailer in the process of hauling timber and affecting the premature failure of the main parts of the fifth wheel coupling are considered. The influence on the resource of the fifth wheel coupling device of strict fulfillment of the mandatory operations of periodic lubrication of the saddle and the base plate of the semitrailer in the process of connecting and disconnecting it with a timber tractor is given. Described is the actual problem associated with excessive consumption of lubricant in the process of applying it to the friction surfaces of the saddle and the base plate of the semitrailer by the traditional method of extrusion. A possible method of dosed supply of the required volume of lubricant through the optimal number of lubrication holes to the friction surfaces is considered, which makes it possible to significantly reduce the cost of maintaining the operable state of the fifth wheel coupling. In order to preliminary evaluate the application of this lubrication method, which ensures the effective functioning of the fifth wheel coupling of a timber tractor with a semitrailer, several series of computer experiments were performed to determine the optimal number of lubrication holes in the saddle that evenly and dosed distribute the lubricant between the saddle and the base plate of the semitrailer.

A steering control system for the tractor – semi-trailer combination vehicle with the electromechanical transmission

The article offers an algorithm for the operation of the steering and active drive control system of a saddle-type tractor – trailer combination. The algorithm allows reducing the width of the cornering corridor when maneuvering at low speeds. In the combination vehicle under study, all the wheels of the tractor and semi-trailer are driving and steered. The algorithm of the steering control system takes into account the current values of the folding angle and speed of the combination vehicle. The active drive control is based on the analysis of the forces in the coupling device. The efficiency and effectiveness of the proposed algorithm has been proved using computational experiments.

INVESTIGATION OF THE DYNAMIC LOAD OF THE JOINT-PLATFORM OF THE JOINT TYPE FROM ROUND PIPES LOADED BY TANKER CONTAINERS

The dynamic loading of the load-bearing structure of the articulated platform car made of round pipes loaded with tank containers was determined. The research was conducted by mathematical modeling. The solution of the equations of motion is carried out in the MathCad software package. It is established that under the influence of a longitudinal force of 2.5 MN on the front stops of the autocoupling, the acceleration on the first section of the platform car is 27.7 m/s² from the side of the force application, and on the second - 24.4 m/s2. To reduce the dynamic load of the load-bearing structure of the platform car, the possibility of using the concept of a harness device on it as an alternative to a typical self-coupling device is considered. The quenching of the kinetic energy of the impact is carried out due to the viscous resistance forces arising in the concept. The proposed implementation allows to reduce the dynamic load of the load-bearing structure of the platform car by 10% compared to the use of a standard self-coupling device. The conducted researches will promote creation of innovative designs of cars-platforms and increase of efficiency of use of railway transport.

Mechanical Anastomotic Coupling Device versus Hand-sewn Venous Anastomosis in Head and Neck Reconstruction—An Analysis of 1694 Venous Anastomoses

Background There is a steep learning curve to attain a consistently good result in microvascular surgery. The venous anastomosis is a critical step in free-tissue transfer. The margin of error is less and the outcome depends on the surgeon’s skill and technique. Mechanical anastomotic coupling device (MACD) has been proven to be an effective alternative to hand-sewn (HS) technique for venous anastomosis, as it requires lesser skill. However, its feasibility of application in emerging economy countries is yet to be established. Material and Method We retrospectively analyzed the data of patients who underwent free-tissue transfer for head and neck reconstruction between July 2015 and October 2020. Based on the technique used for the venous anastomosis, the patients were divided into an HS technique and MACD group. Patient characteristics and outcomes were measured. Result A total of 1694 venous anastomoses were performed during the study period. There were 966 patients in the HS technique group and 719 in the MACD group. There was no statistically significant difference between the two groups in terms of age, sex, prior radiotherapy, prior surgery, and comorbidities. Venous thrombosis was noted in 62 (6.4%) patients in the HS technique group and 7 (0.97%) in the MACD group (p = 0.000). The mean time taken for venous anastomosis in the HS group was 17 ± 4 minutes, and in the MACD group, it was 5 ± 2 minutes (p = 0.0001). Twenty-five (2.56%) patients in the HS group and 4 (0.55%) patients in MACD group had flap loss (p = 0.001). Conclusion MACD is an effective alternative for HS technique for venous anastomosis. There is a significant reduction in anastomosis time, flap loss, and return to operation theater due to venous thrombosis. MACD reduces the surgeon’s strain, especially in a high-volume center. Prospective randomized studies including economic analysis are required to prove the cost-effectiveness of coupler devices.