Number Of Work Cycles Research Articles

Особенности интерпретации результатов резистограмм при оценке качества стволовой древесины сосны

The article presents the resistogram analysis results of the healthy and damaged pine trunks with the systematic resistance error identification to drilling of pine wood when using the resistograph. The influence of the bore drilling channel length on the amount of resistance to drilling of pine wood has been established. It is indicated that when using resistograms as an express method for assessing the quality of wood trunks, it is necessary to adjust its dataset. A method of modeling the effect of the trunk drilling depth on the amount of resistance to wood drilling is proposed. The influence of the bore drilling channel length on the value of the systematic error of the resistance to pine wood drilling was revealed. The systematic error of pine wood drilling resistance depends on the number of the drill bit working cycles. When the number of work cycles is up to 100, the systematic error is up to 20 Resi; from 100 to 200 — from 20 to 60 Resi; more than 200 — from 60 to 200 Resi. When using a drill bit after 100 working cycles, a linear dependence of systematic errors of resistance to pine wood drilling on the length of the bore drilling channel is noted.

Effect of cobalt (nickel) oxide on the properties of zinc\u2013titanium sorbents for high temperature desulphurization of model coal gas

Zn–Ti–Co(Ni) sorbents for H2S removal from model hot coal were prepared and characterized. Effects of cobalt (Co) and nickel (Ni) on the sorbents texture, structure, H2S sorption capacity and regeneration properties were determined. TiO2 formed mixed metal oxides with CoO and NiO in the fresh sorbents, while TiO2 and nanocrystalline sulfides of Zn, Co, Ni were found in sulphided ones. The oxidative regeneration of sulphided sorbents re-formed mixed oxides. Sorption capacity of studied materials increased along with an increase of the amount of added Co (Ni) and also with the number of work cycles. Co-doped Zn–Ti materials adsorbed up to 244% more sulfur than these of Zn–Ti, while Ni-doped materials adsorbed ca. twice more H2S than the corresponding Co-doped sorbents. The addition of Co (Ni) decreased the temperature of ZnS oxidation. The catalytic effect of the Co (Ni) oxides on the oxidation of ZnS was suggested.

Construction of Stretching-Bending Sequential Pattern to Recognize Work Cycles for Earthmoving Excavator from Long Video Sequences.

Counting the number of work cycles per unit of time of earthmoving excavators is essential in order to calculate their productivity in earthmoving projects. The existing methods based on computer vision (CV) find it difficult to recognize the work cycles of earthmoving excavators effectively in long video sequences. Even the most advanced sequential pattern-based approach finds recognition difficult because it has to discern many atomic actions with a similar visual appearance. In this paper, we combine atomic actions with a similar visual appearance to build a stretching–bending sequential pattern (SBSP) containing only “Stretching” and “Bending” atomic actions. These two atomic actions are recognized using a deep learning-based single-shot detector (SSD). The intersection over union (IOU) is used to associate atomic actions to recognize the work cycle. In addition, we consider the impact of reality factors (such as driver misoperation) on work cycle recognition, which has been neglected in existing studies. We propose to use the time required to transform “Stretching” to “Bending” in the work cycle to filter out abnormal work cycles caused by driver misoperation. A case study is used to evaluate the proposed method. The results show that SBSP can effectively recognize the work cycles of earthmoving excavators in real time in long video sequences and has the ability to calculate the productivity of earthmoving excavators accurately.

Experimental tests of static friction coefficient for selected material combinations of expanded graphite - steel used in sealing nodes

The paper presents the results of static friction coefficient tests of selected material sets used in sealing nodes. Four graphite materials were tested - pure expanded graphite, expanded graphite with the addition of PTFE plastic of different densities (1.4 and 1.8 [g/cm3]) and expanded graphite laminated with austenitic steel foil - matching the steel surface. The combinations operated in a reciprocal movement. The measurements were made at different unit pressures (0.5, 2 and 5 MPa) and for different work cycles (0, 500, 1500 and 3000). On the basis of the results obtained, it was found that both the load and the number of work cycles have a significant influence on the value of the static friction coefficient of the tested materials. Not without significance is also the density of selected graphite materials. It was found that expanded graphite with PTFE and density of 1.8 g/cm3 was characterized by the lowest static friction coefficient in comparison with other materials. It is also worth noting the fact of a layer on the steel surface of combination which promotes the formation of stick-slip phenomenon.

Tribological examination of lumbar intervertebral disc implants

The article presents results of friction and wear tests of three-piece systems of the intervertebral disc implant. The number of work cycles proved to have an effect on the coefficient of friction for polyethylene-on-metal and metal-on-metal tribojoints. In addition, for polyethylene-on-metal tribojoints, the effect of compressive force on the coefficient of friction was specified. The influence of working cycles on roughness changes of implant’s working surfaces was analyzed. Based on the microscopic examination of the working surface of implants and morphology of the wear products, the wear mechanism was described. Studies were performed at the Laboratory of Surface Engineering and Tribology in the Metal Forming Institute in Poznan using a SBT-03 simulator.

Assessment System of Remaining Life for Bridge Crane Based on the Internet of Things

In view of the highly randomness and uncertainty in the working condition of crane, take bridge crane as the research object. Firstly, based on the technology of the internet of things, the load capacity and the number of work cycles would be recorded, and the fatigue stress spectrum would be formed. Secondly, based on the Miners fatigue damage accumulation theory and the rain-flow algorithm, the equivalent stress amplitude would be obtained. Thirdly, curve regression model has been used to characterizing the relationship between the crack propagation and equivalent stress amplitude, and predicting the current crack size. Lastly, taking the predicted value of the crack size into the fracture mechanics formula, and estimated the remaining fatigue life of the bridge crane. The example demonstrated that, it is simple and practical to apply the techniques of the internet of things and the regression forecasting to the data collection and crack size prediction; it not only be able to estimate the remaining fatigue life quickly and accurately, but also be able to overcome the drawback of requiring the initial crack size in the fracture mechanics.

Biomechanical modelling and evaluation of construction jobs for performance improvement

Occupational risk factors, such as awkward posture, repetition, lack of rest, insufficient illumination and heavy workload related to construction-related MMH activities may cause musculoskeletal disorders and poor performance of the workers, ergonomic design of construction worksystems was a critical need for improving their health and safety wherein a dynamic biomechanical models were required to be empirically developed and tested at a construction site of Tata Steel, the largest steel making company of India in private sector. In this study, a comprehensive framework is proposed for biomechanical evaluation of shovelling and grinding under diverse work environments. The benefit of such an analysis lies in its usefulness in setting guidelines for designing such jobs with minimization of risks of musculoskeletal disorders (MSDs) and enhancing correct methods of carrying out the jobs leading to reduced fatigue and physical stress. Data based on direct observations and videography were collected for the shovellers and grinders over a number of workcycles. Compressive forces and moments for a number of segments and joints are computed with respect to joint flexion and extension. The results indicate that moments and compressive forces at L5/S1 link are significant for shovellers while moments at elbow and wrist are significant for grinders.