Position Operators Research Articles

Integrating human-centric simulations in educational production lines: advancing ergonomics for industry 5.0 applications

This research in the Industry 5.0 field focuses on a human-centered simulation of the FAS200 SMC educational production line, utilizing Tecnomatix Process Simulate Human software for developing a virtual human environment. A key aspect of this study is the integration of inertial sensors, enhancing the accuracy and depth of ergonomic analysis. These sensors play a pivotal role in capturing precise human movement data, crucial for ergonomic assessments. Adopting a defined working methodology, the study extensively employs the RULA method to evaluate operator postures in the production line. This approach has led to significant ergonomic improvements, evidenced by a 40 percent reduction in the RULA index at each workstation. The integration of inertial sensors has been instrumental in achieving these results, providing detailed insights into human movements and interactions with the production environment. The research transcends traditional ergonomic assessments by incorporating a new human-centered approach, emphasizing the well-being of individuals working alongside machines. This approach, bolstered by the use of inertial sensors, marks a significant advancement in ergonomic studies, aligning with the principles of Industry 5.0. The findings hold substantial potential for application in industrial settings, signaling a shift towards more human-friendly and efficient industrial practices.

Protecting Our Own: A Method for Reducing Breast Radiation Exposure in Healthcare Workers.

Standard lead aprons do not protect the female breast adequately from radiation exposure, which has been associated with breast cancer in healthcare workers. A novel lead shield was designed to reduce radiation to the breast, axilla, and thyroid (BAT). A procedure room was simulated with an anthropomorphic phantom representing the operator. Dosimeters were positioned on the outer quadrant of each breast, the chest, the thyroid, and deep inside of a phantom acrylic female torso with neck and head. Standard lead vest plus a thyroid shield was used as control and compared to standard lead vest plus BAT shield. Three operator and two image receptor positions were tested. The reductions in radiation exposure were calculated. The standard vest plus BAT shield provided significant reductions in radiation exposure for all anatomic locations compared to control. When averaging all operator positions, the BAT provided reductions of 91% (p < 0.0001) for near breast. Reductions for far breast, chest, thyroid, and deep tissues were 76% (p = 0.016), 94% (p < 0.0001), 52% (p = 0.026), and 60% (p = 0.004). With operator 90° to the table using a cross-table lateral beam, the BAT provided a 97.7% reduction in radiation to the near breast and significant reduction in radiation to the chest, thyroid, and deep tissues. The BAT shield reduces radiation exposure to the breast, chest, thyroid and deep hematopoietic tissues. Such shields could benefit healthcare workers to reduce the risk of breast cancer and other radiation-associated cancers.

AI-based engine performance prediction cum advisory system to maximise fuel efficiency and field performance of the tractor for optimum tillage

Tractor engine performance is critical for optimizing energy efficiency in tillage operations across various soil conditions. This study introduces an artificial neural network (ANN) based novel approach for predicting and optimizing specific fuel consumption (SFC) and fuel consumption per tilled area (FCA), during tillage operations. Field tests were conducted to collect the data on rear axle torque, forward velocity, fuel consumption, throttle position, engine speed, and depth of operation under soft, medium, and hard soil conditions while using a reversible MB plough, offset disc harrow, and rigid tyne cultivator. Tractor engine performance was predicted using ANN and optimized by matching the required rear axle power with the available rear axle power. Optimal operating parameters for three distinct tillage implements, each associated with varying soil types and tillage depths, were determined based on minimizing SFC and FCA. An integrated ANN-based user advisory system was developed to provide tractor engine performance predictions and recommendations for optimal operating parameters to maximize fuel efficiency. The recommendations were validated with actual field data, resulting in Mean Absolute Percentage Errors of 7.56% and 8.98% for MB plough, 11.19% and 9.36% for offset disc Harrow, and 10.90% and 10.57% for cultivator, respectively, for SFC and FCA. Highlights ANN-based novel approach is proposed to optimize fuel efficiency during tillage Advisory system is developed to recommend parameters for optimum tillage Suggestions for minimum SFC and FCA are provided in soft, medium and hard soil The accuracy and reliability of advisory system are proven by field validation

СТАБИЛИЗАЦИЯ ПРОЦЕССА – УСЛОВИЕ ЕГО ОБЪЕКТИВНОГО ИССЛЕДОВАНИЯ

Research of the interrelationships between the time periods of stabilization of the technological process of trier grain cleaning from: feeding the grain mixture into the trier; its initial contamination; speed mode of operation and angular position of the output tray relative to the horizon are satisfied. They were carried out using experimental equipment that provided separate, regulated and continuous supply of grain mixture components into the trier with a looped movement of purified grain. Standard methods and instruments, as well as special instruments developed at the Federal State Budgetary Institution VNIITiN, were used to assess the physical and mechanical properties of the components of the grain mixture. It was found that with a supply of 1.2 t/h, an initial contamination of 1.3% and a lifting angle of the output tray of 55°, the speed mode of operation of 36.0 rpm is excessive, while stabilization of the process is not completed even after 15 minutes (92% ), the length of the free section of the cellular surface is 0.70 - 0.75 m, which increases the level of residual grain contamination to 0.025 - 0.04%, which does not meet the requirements for seeds of the OS category. The possibility of reducing the comparable level of process stabilization by 6 times when the operating speed is reduced to 34.6 rpm (by 3.9%) has been confirmed. Reducing the operating speed to 34.0 rpm leads to an increase in process losses to 16.85%. It has been established that with an increase in the initial contamination of the grain mixture to 2.6%, the stabilization period of the process at a speed mode of 34.6 rpm increases from 4.5 to 5.5 minutes, and technological losses reach the maximum permissible value (5%). The method for calculating the actual degree of stabilization of the process with its assessment based on the removal of impurities has been refined.

FINANCIAL ANALYSIS AND VALUATION OF SELECTED UK LISTED COMPANY: A CASE STUDY

Objective: The objective of this study is to investigate the financial analysis and valuation of UK listed companies, with the aim of gaining insight into the financial performance and operational position of Hill and Smith Plc and other key players in the industry. Theoretical Framework: In this study, the main concepts and theories that underpin the research include the irrelevance theory, trade off theory, pecking order theory and market timing theory. These theories explain the underlying factors that determine the financing and valuation choices of listed firms. Method: The study adopted the net assets valuation, dividend discount model, free cashflows, earnings model, comparative companies, and comparative transactions valuation methodologies. The study adopted Hill and Smith Plc as a case study, extracting relevant data from its annual financial records. Results and Discussion: The study revealed a +4.17% abnormal return, suggesting an exceptional performance. It compared financial positions with peers like Morgan Advanced Materials and Keller Group, employing multiple valuation methods. The earnings model indicated a share price of £14.1, suggesting a potential overvaluation in the stock market at £10.0 per share. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of corporate finance and valuation. These implications impact various stakeholders such as the researched firms, investors, and academia. Originality/Value: This study contributes to the literature by highlighting the valuation methodologies employed in the study, emphasisng the importance of accurate valuation techniques in informing investment decisions.

Encoding a Many-Body Potential Energy Surface into a Grid-Based Matrix Product Operator.

An efficient algorithm for compressing a given many-body potential energy surface (PES) of molecular systems into a grid-based matrix product operator (MPO) is proposed. The PES is once represented by a full-dimensional or truncated many-body expansion form, which is obtained by ab initio calculations at each grid mesh point, and then all terms in the expansion are compressed and merged into a single MPO while maintaining the bond dimension of the MPO as small as possible. It was shown that the ab initio PES of the H2CO was compressed by more than 2 orders of magnitude in the size of the site operators without loss of accuracy. By the use of grid basis, the tensor rank of the site operators of the MPO is reduced from four to three due to the diagonal nature of the position-dependent operators on grid basis, which significantly reduces the computational cost of the tensor contractions required in the real and imaginary time evolution of the matrix product state (MPS) wave functions with the grid-based MPO (Grid-MPO) Hamiltonian. Similar to other grid-based methods, Grid-MPO is easily applicable to any kinds of potentials of molecular systems, such as analytical empirical model potentials expressed by position operators and ab initio potentials, if the values at the grid points are available. Using the Grid-MPO combined with the MPS, we calculated the time correlation function of the Eigen cation to predict the infrared spectrum and compared with the experimental and the previous theoretical studies. The actual scaling with the size of systems was examined for the multidimensional Henon-Heiles Hamiltonian. It was shown that the method is considerably accelerated by the graphic processing unit (GPU) because the sizes of site operators were kept small and all tensors were able to be stored on the VRAM of a GPU.

Effects of dust controls on respirable coal mine dust composition and particle sizes: case studies on auxiliary scrubbers and canopy air curtain

Control of dust in underground coal mines is critical for mitigating both safety and health hazards. For decades, the National Institute of Occupational Safety and Health (NIOSH) has led research to evaluate the effectiveness of various dust control technologies in coal mines. Recent studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains (CACs) to reduce respirable dust in key operator positions. While detailed dust characterization was not a focus of such studies, this is a growing area of interest. Using preserved filter samples from three previous NIOSH studies, the current work aims to explore the effect of two different scrubbers (one wet and one dry) and a roof bolter CAC on respirable dust composition and particle size distribution. For this, the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive X-ray. Results indicate that dust composition was not appreciably affected by either scrubber or the CAC. However, the wet scrubber and CAC appeared to decrease the overall particle size distribution. Such an effect of the dry scrubber was not consistently observed, but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return air. Aside from the insights gained with respect to the three specific dust control case studies revisited here, this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.

The principle of magnetic flux switch

This paper introduces an innovative Magnetic Switch (MFS) designed to control and alter magnetic flux within energy system components, offering an alternative to conventional power electronic devices. The MFS comprises a low-current control coil, a control core, and a high-density magnetic flux-carrying main core combined with a main coil energy system. In this novel magnetic configuration, when a low-power current excites the control coil, the magnetic flux in the main core (supplied by the main coil) decreases to nearly zero. Conversely, when the control coil disconnects from the power source, the magnetic flux within the main core attains its maximum value. This operation positions the MFS as a groundbreaking concept within magnetic-based energy systems, akin to transistors in power electronics. The main outcomes of the MFS concept are that it can vary the magnetic flux of the main core in the large range, and it is a fast magnetic switch with a simple and low power loss control circuit and an independent control coil from the main coil. Analytical studies thoroughly elucidate the performance and advantages of this proposed magnetic switch, substantiated by Finite Element Method simulations and experimental prototype outcomes.

Analysis of Rail Potential and Stray Current with an Unified Chain Model of Dual Traction Power Supply System

In dual traction power supply systems, the overhead catenary system operates in different power supply modes. It passes across the AC section, DC section, and a neutral part, which influences the features and properties of the feedback current and aggregates its effects on stray current and rail potential. This research paper presents an integrated model of an AC and DC traction power system (TPS), along with a unified chain equivalent circuit model, the ground wire through the AC section, and the insulation joints fixed in the AC–DC neutral section under different operating positions. To make a unified impedance and admittance matrix for traction network, a virtual conductor wire has been added in the DC section to make the balance order of the TPS. The influence of reflex system configuration on rail potential, stray current, and distribution of rail potential at AC and DC stations has also been calculated. The simulation results demonstrate that establishing the insulation joints in the AC–DC section and using ground wires in the AC part can significantly decrease the stray current and rail potential.

PT-Finder: A multi-modal neural network approach to target identification

Efficient target identification for bioactive compounds, including novel synthetic analogs, is crucial for accelerating the drug discovery pipeline. However, the process of target identification presents significant challenges and is often expensive, which in turn can hinder the drug discovery efforts. To address these challenges machine learning applications have arisen as a promising approach for predicting the targets for novel chemical compounds. These methods allow the exploration of ligand–target interactions, uncovering of biochemical mechanisms, and the investigation of drug repurposing. Typically, the current target identification tools rely on assessing ligand structural similarities. Herein, a multi-modal neural network model was built using a library of proteins, their respective sequences, and active inhibitors. Subsequent validations showed the model to possess accuracy of 82 % and MPRAUC of 0.80. Leveraging the trained model, we developed PT-Finder (Protein Target Finder), a user-friendly offline application that is capable of predicting the target proteins for hundreds of compounds within a few seconds. This combination of offline operation, speed, and accuracy positions PT-Finder as a powerful tool to accelerate drug discovery workflows. PT-Finder and its source codes have been made freely accessible for download at https://github.com/PT-Finder/PT-Finder.

The Explicit Form of the Unitary Representation of the Poincaré Group for Vector-Valued Wave Functions (Massive and Massless), with Applications to Photon Localization and Position Operators

We geometrically derive the explicit form of the unitary representation of the Poincaré group for vector-valued wave functions and use it to apply speed-of-light boosts to a simple polarization basis to end up with a Hawton–Baylis photon position operator with commuting components. We give explicit formulas for other photon boost eigenmodes. We investigate the underlying affine connections on the light cone in momentum space and find that while the Pryce connection is metric semi-symmetric, the flat Hawton–Baylis connection is not semi-symmetric. Finally, we discuss the localizability of photon states on closed loops and show that photon states on the circle, both unnormalized improper states and finite-norm wave packet smeared-over washer-like regions are strictly localized not only with respect to Hawton–Baylis operators with commuting components but also with respect to the noncommutative Jauch–Piron–Amrein POV measure.

Research and application of bag filter system for railway ballast bed coal suction vehicles: An optimization and application study.

The current bag filter system used by railway ballast bed coal suction vehicles for cleaning coal dust from railway tunnels has low operational efficiency and generates significant volumes of dust. This paper describes a simulation test unit designed to enhance the dust removal performance in railway tunnels. The flow field inside the simulation test unit is investigated under different operating conditions through numerical simulations, and the variations in air volume and working resistance, total dust collection efficiency, and optimal operating parameters of a pulse cleaning system are identified through a series of experiments. The numerical results show that the pulse cleaning system does not significantly affect the uniformity of the flow field distribution at the bottom of the filter cartridge during the process of operation. The experimental research indicates that the simulation test unit satisfies the design requirements, achieving an average total dust removal efficiency of 99.93%. A field application shows that the total dust mass concentration at the operator position can be reduced from 335.8 mg∙m-3 to 4.2 mg∙m-3, effectively improving the operating environment within the tunnel.

A novel cooperative optimization method of course and speed for wing-diesel hybrid ship based on improved A* algorithm

The wing-diesel hybrid ship, utilizes a wind propulsion system, which is significantly influenced by weather conditions. Therefore, a cooperative optimization method for course and speed is proposed based on an improved A* algorithm, considering weather changes and the ship characteristics, to achieve further improvement in the ship operational energy efficiency. Firstly, a meteorological and hydrological dataset is utilized to establish a dynamic maritime area model with complex weather conditions. Based on this model, the paper considers the actual navigation circumstances to define prohibited and navigable areas. Secondly, the improved A* algorithm incorporates the impact of weather on wing-sails. The improved A* algorithm considers the ship operating position and enhances the evaluation function by variables normalization of fuel consumption and voyage time. This cooperative optimization ensures the maximization of wind energy utilization, thereby achieving the goal of reducing fuel consumption while meeting the overall voyage time requirement. Experimental validation is conducted with the ship “New Aden” in the Indian Ocean region, and the results show that, compared to the original route, the optimized route reduces total fuel consumption by 5.48%, increases the navigation distance by up to 2.18% and increases the navigation time by 5.74%.

Radiologically derived 3D virtual models for neurosurgical planning

Three dimensional (3D) virtual models for neurosurgery have demonstrated substantial clinical utility, especially for neuro-oncological cases. Computer-aided design (CAD) modelling of radiological images can provide realistic and high-quality 3D models which neurosurgeons may use pre-operatively for surgical planning. 3D virtual models are useful as they are the basis for other models that build off this design. 3D virtual models are quick to segment but can also be easily added to normal neurosurgical and radiological workflow without disruption. Three anatomically complex neuro-oncology cases that were referred from a single institution by three different neurosurgeons were segmented and 3D virtual models were created for pre-operative surgical planning. A face-to-face interview was performed with the surgeons after the models were delivered to gauge the usefulness of the model in pre-surgical planning. All three neurosurgeons found that the 3D virtual model was useful for presurgical planning. Specifically, the virtual model helped in planning operative positioning, understanding spatial relationship between lesion and surrounding critical anatomy and identifying anatomy that will be encountered intra-operatively in a sequential manner. It provided benefit in Multidisciplinary team (MDT) meetings and patient education for shared decision making.3D virtual models are beneficial for pre-surgical planning and patient education for shared decision making for neurosurgical neuro-oncology cases. We believe this could be further expanded to other surgical specialties. The integration of 3D virtual models into normal workflow as the initial step will provide an easier transition into modalities that build off the virtual models such as printed, virtual, augmented and mixed reality models.

Effectiveness Study on Mind Mapping Approach to Students’ Operation Position Performance and Creativity on Traditional Chinese Painting

Under current diplomaism, students’ painting ability is cultivated, but the creativity development is restricted. Students mainly learn painting skills that technique training is mostly emphasized. To improve such a problem, it is necessary to build the operation position performance ability and the value and attitude towards creativity, cultivate creativity with multiple intelligences as the structure, stress on the creativity process and taking pressure in the experience, and integrate creativity into course teaching. Using experimental design model for this study, 202 art major students of a university in China, as the experimental subjects, are preceded the 18-week (2 hours per week for total 36 hours) experimental teaching research. The research results show that 1.mind mapping approach would positively affect operation position performance, 2.mind mapping approach would positively affect creativity, and 3.operation position performance shows significant and positive effects on creativity. According to the results to propose discussions, it is expected to provide students with the learning strategy of creative thinking through teachers’ teaching model, cultivate students’ operation position performance and creativity on traditional Chinese painting with the system structure and divergent thinking of mind mapping symbolism, as well as actually apply to the artistic creation of traditional Chinese painting.

Kubo formula for dc conductivity: Generalization to systems with spin-orbit coupling

We revise the Kubo formula for the electric dc conductivity in the presence of spin-orbit coupling (SOC). We discover that each velocity operator that enters this formula differs from ∂H/∂p, where H is the Hamiltonian and p is the canonical momentum. Moreover, we find an additional contribution to the Hall dc conductivity from noncommuting coordinates that is missing in the conventional Kubo-Středa formula. This contribution originates from the “electron-positron” matrix elements of the velocity and position operators. We argue that the widely used Rashba model does in fact provide a finite anomalous Hall dc conductivity in the metallic regime (in the noncrossing approximation) if SOC-corrections to the velocity and position operators are properly taken into account. While we focus on the response of the charge current to the electric field, linear response theories of other SOC-related effects should be modified similarly. Published by the American Physical Society 2024

The mean square displacement of a ballistic quantum particle

A commonly used quantum mechanical formulation of the mean square displacement δ x 2 ( t ) is based on the quantum correlation function of the position operator. While this quantity yields the classically expected result δ x 2 ( t ) ∝ t 2 for a ballistic particle in the interval topology, it is found here to diverge at essentially all times, when evaluated on infinitely large rings. A somewhat different formulation of the mean square displacement in quantum mechanics was proposed in a previous work (R. Marquardt, Mol. Phys. 119, e1971315 (2021)) and yielded the result δ x 2 ( t ) ∝ t for the ballistic particle on an infinitely large ring. Here, it is shown analytically that that formulation yields δ x 2 ( t ) ≡ 0 for the ballistic particle on an infinitely long interval. The two formulations define two different, topology dependent quantities that have the dimension of an area and that could in principle be determined from the same experiment, following a measurement idea proposed in the aforementioned work. That idea is critically reviewed here.

Operative Positioning and Intraoperative-Acquired Pressure Injury: A Retrospective Cohort Study.

To comprehensively assess the association between operative positioning with intraoperative-acquired pressure injury (IAPI) development. This retrospective cohort study included 455 patients who underwent surgery between October 2020 and January 2021. The authors grouped patients by operative positioning into the prone position and nonprone position groups. They used propensity-score matching at a 1:2 ratio to control for preoperative confounders, applied multiple logistic regression models to analyze the effects between positioning and IAPI, and assessed interactions of positioning and intraoperative factors on IAPI. The final enrollment was 92 cases in the prone position group and 181 in the nonprone position group. Multivariable logistic analysis suggested that the prone position had a 2.92 times higher risk of IAPI than the nonprone position (odds ratio, 2.92; 95% CI, 1.13-7.57; P = .026). Subgroup analysis showed a significant multiplicative interaction between positioning and foam dressing on IAPI (P < .05), which was not observed in other intraoperative factors (P > .05). This study provides evidence that prone operative positioning can increase IAPI risk. Patients in the prone position may particularly benefit from using dressings in Chinese populations. Further large-sample longitudinal studies are required to confirm these findings.

Workload Simulation and Comfort Evaluation of Workover Rig Driller

Considering that the method of evaluating comfort by subjective feeling isn’t precise enough, and there are few studies on the comfort of the wo-rkover rig operation, taking the XJ70 workover rig as an example, comprehen-sively considering the impact of operating time and operating cabin layout para-meters, the digital model of the human body sitting posture of Chinese adult males with typical percentiles is established in the AMS biomechanics software, the model of brake handle and seat is imported, and the inverse dynamics simu-lation of the brake handle operation is performed; Taking the muscle activity of relevant muscle groups as the evaluation index, the influence and mapping rela-tionship of sitting height and backrest inclination on the muscle groups during the brake handle operation are studied. The handling comfort evaluation model based on the muscle loads is built, which provides a new way for the evaluation of comfort and has a certain guiding significance for selecting comfortable operating posture and optimizing the adjustable range of seat.

Spectral and Krylov complexity in billiard systems

In this work, we investigate spectral complexity and Krylov complexity in quantum billiard systems at finite temperature. We study both circle and stadium billiards as paradigmatic examples of integrable and nonintegrable quantum-mechanical systems, respectively. We show that the saturation value and timescale of spectral complexity may be used to probe the nonintegrability of the system since we find that when computed for the circle billiard, it saturates at a later timescale compared to the stadium billiards. This observation is verified for different temperatures. Furthermore, we study the Krylov complexity of the position operator and its associated Lanczos coefficients at finite temperature using the Wightman inner product. We find that the growth rate of the Lanczos coefficients saturates the conjectured universal bound at low temperatures. Additionally, we also find that even a subset of the Lanczos coefficients can potentially serve as an indicator of integrability, as they demonstrate erratic behavior specifically in the circle billiard case, in contrast to the stadium billiard. Finally, we also study Krylov entropy and verify its early-time logarithmic relation with Krylov complexity in both types of billiard systems. Published by the American Physical Society 2024