Modelling of technological process of joining steel ropes with the use of powder antifriction material and a conductor

When determining the causes of structural defects of a steel rope, the technology of carrying out work on splicing by a team of specialists was studied in detail. Field observations and experimental studies, as well as mathematical modeling of the process of structural defects formation in the rope joint section, allowed to establish that the cause is the imperfection of the existing technology for performing splice work [1-5]. The existing technology directly depends on the experience (professionalism) of a splicing team and provides for the work on splicing, as a solution to a new problem for every hawser, expressed in the design and calculation of the main parameters, according to the established standards of the rope manufacturer. It is noted that this labor function negatively affects a person, causing dangerous and harmful factors of the working environment, such as: severity and intensity of the labor process. Under the influence of dangerous and harmful factors, the specialist is subject to: static and dynamic overload, mental overstrain, neuropsychiatric overload, which negatively affect a person and, as a result, affect the quality of the work performed as a whole. The total accumulation of dangerous factors in the course of work leads to the decrease in the quality of the obtained results and deviation from the normalized indicators, which is unacceptable and leads to the formation of structural defects of a steel rope.

Study of Rail Squat Characteristics through Analysis of Train Axle Box Acceleration Frequency

In this study, a method for detecting the railway surface defects called “squats” using the ABA (Axle Box Acceleration) measurement of trains was proposed. ABA prototype design, implementation, and field tests were conducted to derive and verify the results. The field test was performed using a proven precision measurement system, and the measured data were signal-processed using a Matlab program. The algorithm used to determine the position of the squats was developed based on wavelet spectrum analysis. This study was verified for a section of a domestic general line and, following field verification for the section, squats was detected with a hit rate of about 88.2%. The main locations where the squats occurred were the rail welds and the joint section, and it was confirmed that in some sections, unsupported sleepers occurred at the locations where the squats occurred.

STUDY ON ARRANGEMENT OF COOLING WATER PIPE TO CONTROL HYDRATION HEAT OF CONCRETE IN BEAM OF CABLE-STAYED BRIDGE

The box girder joint section of the Yangtze River Highway Bridge is taken as the research background, and the finite element software MIDAS/FEA is used to simulate the hydration heat of concrete to the layout of cooling water pipe in building mass concrete. The finite element calculation results are in well agreement with the measured data. On this basis, the influence of changing the diameter and distance of the cooling water pipe, the inlet temperature and the flow rate on the temperature of hydration heat is studied. The results show diameter of the cooling water pipe and inlet temperature have a significant effect on the temperature of hydration heat. The change of water flow rate has little effect on the temperature of hydration heat. It provides a reference for the layout of the same concrete cooling water pipe arrangement.

History of Women in Neurosurgery (WINS)

In 2020, the Women in Neurosurgery (WINS) organization, a joint section of the AANS and Congress of Neurological Surgeons, celebrated 30 years since its inception. In this paper, the authors explore the history of WINS from its beginnings through its evolution over the past three decades. The achievements of the group are highlighted, as well as the broader achievements of the women in the neurosurgical community over this time period.

A Closed-Form Solution for the Inverse Kinematics of the 2n-DOF Hyper-Redundant Manipulator Based on General Spherical Joint

This paper presents a closed-form inverse kinematics solution for the 2n-degree of freedom (DOF) hyper-redundant serial manipulator with n identical universal joints (UJs). The proposed algorithm is based on a novel concept named as general spherical joint (GSJ). In this work, these universal joints are modeled as general spherical joints through introducing a virtual revolution between two adjacent universal joints. This virtual revolution acts as the third revolute DOF of the general spherical joint. Remarkably, the proposed general spherical joint can also realize the decoupling of position and orientation just as the spherical wrist. Further, based on this, the universal joint angles can be solved if all of the positions of the general spherical joints are known. The position of a general spherical joint can be determined by using three distances between this unknown general spherical joint and another three known ones. Finally, a closed-form solution for the whole manipulator is solved by applying the inverse kinematics of single general spherical joint section using these positions. Simulations are developed to verify the validity of the proposed closed-form inverse kinematics model.