Confined and Eruptive Catastrophes of Solar Magnetic Flux Ropes Caused by Mass Loading and Unloading

It is widely accepted that coronal magnetic flux ropes are the core structures of large-scale solar eruptive activities, which have a dramatic impact on the solar-terrestrial system. Previous studies have demonstrated that varying magnetic properties of a coronal flux rope system could result in a catastrophe of the rope, which may trigger solar eruptive activities. Since the total mass of a flux rope also plays an important role in stabilizing the rope, we use 2.5 dimensional magnetohydrodynamic numerical simulations in this article to investigate how a flux rope evolves as its total mass varies. It is found that an unloading process that decreases the total mass of the rope could result in an upward (eruptive) catastrophe in the flux rope system, during which the rope jumps upward and the magnetic energy is released. This indicates that mass unloading processes could initiate the eruption of the flux rope. Moreover, when the system is not too diffusive, there is also a downward (confined) catastrophe that could be caused by mass loading processes via which the total mass accumulates. The magnetic energy, however, is increased during the downward catastrophe, indicating that mass loading processes could cause confined activities that may contribute to the storage of energy before the onset of coronal eruptions.

Testing Device for Hydraulic Rope System Tensile Force Equalizing Unit

Rope elevators, also referred to as traction elevators, have a cabin suspended from a system of ropes. The system of ropes consists of at least two load-bearing steel ropes with six strands or, from the point of view of easier bending, and currently more widespread, ropes with eight strands. Lifting or lowering of the car, run between the guides, is ensured by the frictional force of the steel ropes in the grooves of the traction disk of the elevator machinery. As the load-bearing capacity of the elevator increases, the required number of load-bearing ropes also increases, especially in the case where small diameter ropes are used in traction elevators. The actual weight of the car and the weight of the load must be evenly distributed among all supporting ropes that are used in the given layout of the elevator. Currently, several principles are known by which it is possible to detect and also change the values of the instantaneous magnitudes of the tensile forces acting in a system of ropes. The paper describes the principle of operation of hydraulic balancing of tensile forces in the system of supporting ropes, which uses the laws of hydromechanics and knowledge of pressure transfer to any place in the fluid, known as Pascal's law. Balancing of differently set values of tensile forces in three supporting ropes, to values of the same size, can be simulated on a test device. This presents the correct operation of the hydraulic system and the possibility of balancing tensile forces in the system of supporting ropes described by the principle of hydraulic device.

Providing the vertical dimension of a self-propelled machine with a rod mechanism for install-ing and fixing the end tower for a mobile ropeway

Mobile ropeways for carrying out loading and unloading and transport and transfer operations in previously unsettled or inaccessible areas, formed with the help of terminal base stations connected by a single rope system on the basis of self-propelled wheeled or tracked chassis of increased carrying capacity and cross-country ability, are a promising type of lifting and transport equipment ensuring the prompt deployment of the necessary technological tools. The article deals with the layout of the mechanism for installing and fixing the end tower using a folding bar, consisting of two articulated links. A mathematical model has been developed that provides the required normative vertical dimension of a self-propelled base station of a mobile ropeway with the aim of its safe independent movement to the place of deployment of the ropeway along general roads. The analysis of the influence of standard dimensional requirements, design dimensions of the chassis carrying frame and the height of the end tower on the main design dimensions of the articulated folding rod in the transport position is carried out. Calculations have shown that the considered design makes it possible to provide the standard vertical dimension of a base station on a 6-axle self-propelled chassis with an end tower length of up to 18 m.

Comparison of clinical efficacy between arthroscopically assisted Tight-Rope technique and clavicular hook plate fixation in treating acute high-grade acromioclavicular joint separations

Introduction: The purpose of this study was to compare the results of arthroscopically assisted reduction of acute acromioclavicular (AC) joint separations with the Tight-Rope technique with results of clavicular hook plate fixation. Materials and Methods: The 28 patients with acute high-grade AC joint dislocation were treated with arthroscopic assisted fixation using the Tight-Rope system, the arthroscopic evaluation and treatment of glenohumeral lesions were performed before AC ligament reconstruction. Each Tight-Rope technique group patient was matched with three controls that underwent clavicular hook plate fixation, and preoperation and postoperative visual analogue scale (VAS) and functional recovery (Constant Score) of the shoulder joint was assessed,. Furthermore, the demographics and clinical characteristics were compared between the two groups. Results: All patients had clinical and radiological results available at 2 years or greater (mean: 34; range: 24–72 months), they were statistically significant improvement in the constant score and VAS score at the end of follow-up respectively ( P < 0.001). Compared with the clavicular hook plate group, Tight-Rope system group patients were incurred significant statistically lower skin incision, hospitalization time and estimated blood loss ( P < 0.001), and the constant score and VAS score at the end of follow-up was significantly higher in the Tight-Rope group ( P < 0.001). Patients who underwent clavicular hook plate had a higher incidence of fixation failure [10 cases (11.9%) versus 2 cases (7.1%)] than those of the Tight-Rope system group. Conclusions: The Tight-Rope technique is advantageous for treating these patients because it is a minimally invasive procedure with low complications and superior clinical outcomes.

Laboratory Device for Checking the Functionality of the Elevator Rope Sensors

The paper describes the structural design of a laboratory device that allows for presenting operation, simulating work procedures and checking functionality of the elevator “rope sensors” when equalizing different tensile forces in partial ropes of a rope system of traction elevators. The laboratory device is modified for checking operations of commonly used rope sensors. In an overwhelming number of cases, elevator technicians use them for setting up the unequally distributed tensile forces in elevator ropes. The device is equipped with three, mutually attached pulleys, over which the rope is installed. The unknown tensile force in the rope is determined by an “indirect method”, i.e. from the resultant of the forces of the rope bent over the pulleys, which have an effect on the force sensor. The tensile force along the rope axis can be determined numerically, but also experimentally, from the inclination angle of the rope installed on the pulleys, diameter of the pulleys, diameter of the rope and the force detected by the force sensor of the stretched rope. The paper presents experimentally obtained tensile force values at the rope sensor, deduced from stretching the rope. The paper also describes the procedure for determining the measured load in the rope by rope sensors of the SWR, SWK and RMT-1 types based on the variable axial force in the rope.

Tension force equalizer in a rope system using a proximity sensor

Different values of tension forces in the load-bearing ropes of elevators, which push the rope into the grooves of the traction discs with different pressure, are the cause of uneven wear of the grooves of the traction discs under operating conditions. Current technical standards in the EU stipulate that the load suspended on load-bearing ropes be evenly distributed to all ropes used, using one of the many construction designs for tension force equalizers in the rope system. The main subject and primary objective of this paper are to present the construction design, 3D model and produced device of one of four produced prototypes, which were constructed in the “Research and Testing Laboratory”, and allow setting of differing values of tension forces in the system of ropes of a traction elevator, to values of the same size. Laboratory measurements were performed on the produced device, which enables the detection of tension forces in ropes and the magnitude of these forces in the required period to be graphically displayed on a PC. The prototype tension force equalizer can show the functionality and practical applicability of the procedure of balancing the levels of tension forces, which are of unequal strengths at the start of the laboratory measurement.