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This study investigates a theoretical model of a Quantum Otto Cycle (QOC) that utilizes a working fluid spin‐chain‐star model. The system consists of a central atom interacting with multiple Heisenberg spin chains. Employing unitary transformations, the spin‐chain‐star system is transformed into a spin‐star model. The work done and heat transferred for three distinct working fluid configurations: the X$X$, XX$XX$, and XYZ$XYZ$ cases are discussed. The efficiency of the heat engine is examined, and a comparative study between the efficiencies of the three configurations is presented. The study assumes two interaction scenarios for the central atom: either with a single chain (resulting in a two‐qubit system after transformation) or with three Heisenberg chains. The results demonstrate that increasing the ratio between the central atom's frequency in the hot bath and the cold bath leads to an enhancement in positive work performed for the X$X$ and XX$XX$ cases. In the XYZ$XYZ$ case, the magnitude of this enhancement exhibits a dependence on the system's temperature. The QOC employing the X$X$ configuration working fluid exhibits superior efficiency compared to the other two configurations. Moreover, increasing the central atom's relative frequency improves efficiency for all three cases. [ABSTRACT FROM AUTHOR]

A comparative study was conducted on Levitation Frame with Mid-set Air Spring (LFMAS) and Levitation Frame with End-set Air Spring (LFEAS). First of all, the work done by air spring force and by track excitation on two levitation frames were analysed, respectively, and the mechanism of the low dynamic interaction of LFMAS with guideway was explained theoretically; then, dynamics simulation and coupled vibration test on LFEAS and LFMAS were carried out using coupled vibration test bench of single levitation frame. Theoretical equations show that both the work done by the air spring forces and by track excitation on LFMAS are less than those on LFEAS under the same vibration condition, demonstrating that LFMAS has better levitation stability than LFEAS. Simulation and test results show that the fluctuation of levitation gap as well as the vibration acceleration of track beam platform, levitation frame and car-body of LFMAS are all smaller than those of LFEAS; with the increase of sine excitation frequency or vehicle speed, the superiority of LFMAS in dynamics performance is more obvious. [ABSTRACT FROM AUTHOR]

The core principle of MIRCE Science revolves around the idea that the purpose of any working system is to perform work. The work is accomplished when a specific measurable function is carried out over time. All working systems require maintenance throughout their lifespan. It is generally understood that, during maintenance, the system is not actively performing any work. The duration and frequency of these tasks directly influence the amount of work lost due to maintenance. That work loss is known to have various consequences, such as monetary, reputational, or social implications. The main objective of this paper is to present how a proactive management approach, known as group replacement, can enhance work productivity compared to individual replacements. Under this strategy, the entire group must be replaced when any item within that group fails. This approach aims to minimize the number of maintenance tasks required and maximize the amount of work accomplished. The provided numerical example demonstrates the practical application of MIRCE Science in quantitatively evaluating the impact of group replacement on work productivity and resource allocation. [ABSTRACT FROM AUTHOR]

Resetting, in which a system is regularly returned to a given state after a fixed or random duration, has become a useful strategy to optimize the search performance of a system. While earlier theoretical frameworks focused on instantaneous resetting, wherein the system is directly teleported to a given state, there is a growing interest in physical resetting mechanisms that involve a finite return time. However employing such a mechanism involves cost and the effect of this cost on the search time remains largely unexplored. Yet answering this is important in order to design cost-efficient resetting strategies. Motivated from this, we present a thermodynamic analysis of a diffusing particle whose position is intermittently reset to a specific site by employing a stochastic return protocol with external confining trap. We show for a family of potentials $U_R(x) \sim |x|^{m}$ with m > 0, it is possible to find optimal potential shape that minimises the expected first-passage time for a given value of the thermodynamic cost, i.e. mean work. By varying this value, we then obtain the Pareto optimal front, and demonstrate a trade-off relation between the first-passage time and the work done.

The flutter response of a rectangular cylinder model with an aspect ratio of 5 is investigated by direct numerical simulation for various Reynolds numbers (Re) and flow angles of attack (α). The results show that the lower α and Re , the larger the torsional amplitude at the critical reduced flow velocity (Ur) corresponding to the occurrence of flutter. High-order Koopman mode analysis method (HOKM) was developed to synchronously capture the inherent flow and structural modes. The element-mode-based energy transfer between cylinders and flow modes was used to reveal the underlying mechanism. HOKM analysis shows that only odd-order modes contribute to the occurrence of flutter, with an augmentation in Ur enhancing this phenomenon. By analyzing the work done in odd-order modes, it is found that the primary mode always occupies the main contribution to the work done. The leading-edge endpoint portion is always where the maximum work is done. An escalation in Re and α notably influences both the spatially relevant part (W Φ) and the temporally relevant part (W c), while an increase in Ur predominantly impacts W Φ. This study offers universal guidance on the safety and protection of ocean engineering structures and flow control strategies. [Display omitted] • High-order Koopman mode analysis method (HOKM) was proposed to synchronously capture the inherent flow and structural modes. • HOKM analysis shows that only odd-order modes contribute to the occurrence of flutter. • An escalation in Re and α notably influences both the W Φ and the W c of work done. [ABSTRACT FROM AUTHOR]

Even though the mechanical behavior of granular soil–rubber mixtures has attracted significant attention and promising applications in geotechnical engineering, less attention has been paid to the influence of creep and long-term response of these composites. The present study examined the compression behavior of two types of sands mixed with recycled granulated rubber with emphasis on the influence of rubber percentage and sand grain type, providing in this way some new insights with emphasis on creep influences. One natural material is composed of Leighton Buzzard quartz sand of noncrushable grains, and the second material is composed of completely decomposed granite of crushable grains (note that the terms crushable and noncrushable refer to the range of maximum overburden pressures applied in the study that ranged from 0.3 to 6.7 MPa). The influence of creep on the compression behavior of the samples was associated with the location (or not) of the pure sand and their mixtures on the normal compression line (NCL) when creep deformations were evaluated. In specific, the rate of creep deformation was found to be independent of the stress level as long as the sample had reached its NCL during compression. Even though for LBS–rubber, there was a clear decrease of the stiffness of the mixtures expressed with the constrained modulus, this was not the case for the CDG–rubber mixtures, and within the scatter of the data, the ratio of creep index to compression index fell in a relatively narrow range (0.005–0.05), suggesting that the creep deformations could be predicted based on conventional oedometer tests with short-term measurements of the applied normal stress. [ABSTRACT FROM AUTHOR]

An Alpha type Stirling engine is different from the other two types in a way that it has two power pistons; one in hot cylinder while other in the cold one. Based on expansion and compression in both cylinders, the engine operates on cyclic manner through external heat source. The efficiency of the engine is recognised by its work done which relies on a number of factors including phase angle, swept volume and dead space. This research demonstrates the efficient working of an Alpha type Stirling engine through optimising the three parameters with a particular focus on the ratio of dead space of two cylinders using Schmidt analysis. Dead space in a Stirling engine is the total void volume in all spaces of engine which does not take part in efficient working of the engine and is unavoidable. The analysis of impact of other parameters to counter the effect of dead space is also the part of examination. The results reveal that negative effects of dead space could be neutralized through suitable selection of other variable parameters. The appropriate combination of swept volumes of both cylinders helps in minimising the effects of dead space and assists in attaining the desired efficiency. The optimal selection of phase angle is also vital, though a little complexed. The results are presented graphically. The examination reveals that negative effects of a parameter could be countered through appropriate selection of other parameters to attain the desired efficiency. [ABSTRACT FROM AUTHOR]

Abstract Background It has been found that alterations in passive muscle properties may be associated with low back pain, and these may be responsible for the altered gait parameters often observed in subjects with back pain. The purpose of the present study was to assess total hip and passive hip extensor moments in people with or without low back pain during the hip flexion component of walking. Methods 52 subjects volunteered for this study (low back pain group, n = 25 (male n = 13, female n = 12), control group, n = 27 (male n = 15, female n = 12)). Passive hip moments were calculated using an adapted force transducer during supine testing. A biomechanical model and predictive equation were used to calculate passive hip moments during walking. Total hip moments were calculated with the use of a 9 camera, 3-D motion-capture system. Findings Independent samples t -tests demonstrated no significant differences between groups for gait parameters or hip or knee angles. Results of the ANOVAs demonstrated significant differences in passive hip flexor moments during the second half of hip flexion (P < 0.05).There were also significant differences in hip power and work done during peaks of power absorption and the second peak of power generation (P < 0.05). Interpretation The present data demonstrates that subjects with low back pain have altered passive hip extensor and total power and work done during walking compared with healthy controls. Biomechanical models should include individual measurements of passive joint moments. Highlights • Low back pain is one of the leading causes of disability globally. • Passive muscle properties may be associated with low back pain. • Total hip moments, power and work done are affected by low back pain. • Interventions should differentiate between passive and active factors. [ABSTRACT FROM AUTHOR]

The current paper aims to investigate the pushover schemes for buildings with asymmetric plan in nonlinear static procedures (NSPs). Moreover, this paper will propose an extension of the energy-based adaptive pushover analysis (EAPA) procedure for the seismic design/assessment of 3D irregular structures, which will be denoted as energy-based pushover-analysis with torque-effects (EPT). This innovative single-run adaptive method is proposed based on the work done produced by modal force in each step of analysis; and is validated on 3D steel structures with asymmetric plan composed from moment-resisting frames. EPT uses the concepts of energy to produce an incremental, adaptive load pattern that takes into account the effects of structural deterioration due to seismic loads, the higher modes of vibration, and the characteristics of the frequency content of the excitations. Also, an innovative MDOF-to-SDOF transformation method is proposed based on energy concept, removing the ambiguity of choosing a controlling point in asymmetric plan buildings. The seismic response obtained from nonlinear analyses under 20 earthquake excitations are plotted over the height of the structures. The results of the analytical studies of these buildings show that the EPT method provides a good prediction of maximum inter-story drifts and displacements over the height of the structures. [ABSTRACT FROM AUTHOR]

A new approach to correlate fatigue crack growth data of metals on the basis of the change in net-section strain energy is presented. Extensive experimental data, including some historically significant fatigue crack growth data, generated using center-cracked (CCT) and single-edge notched (SENT) tension specimens, are used to demonstrate this correlation. It is shown that this correlation, quite remarkably, is as strong as that based on the stress intensity factor range (ΔK) in fracture mechanics. The reason for this surprising similarity is explored using the analysis of the net-section stress increase in fracture mechanics specimens. It is found that the actual role of the finite-width-correction factor in fracture mechanics is to create the stress amplification effect on the finite specimen, having a given crack length, to produce the same K as that of an infinite specimen. The present work demonstrates that the phenomenon of fatigue crack growth can be easily understood on the basis of the accumulated change in net-section strain energy which directly relates to the accumulated work done at the loading ends, which determines the rate of fatigue crack growth. It is a simpler and a physical approach for the accurate description of fatigue crack growth behavior of metals. The approach simultaneously validates the use of fracture mechanics parameters (∆K) for fatigue crack growth, by providing the insight that the physical meaning of stress intensity factor is embedded in the change in the net-section strain energy. [ABSTRACT FROM AUTHOR]

Toe-out/-in gait has been prescribed in reducing knee joint load to medial knee osteoarthritis patients. This study focused on the effects of toe-out/-in at different walking speeds on first peak knee adduction moment (fKAM), second peak KAM (sKAM), knee adduction angular impulse (KAAI), net mechanical work by lower limb as well as joint-level contribution to the total limb work during level walking. Gait analysis of 20 healthy young adults was done walking at pre-defined normal (1.18m/s), slow (0.85m/s) and fast (1.43m/s) walking speeds with straight-toe (natural), toe-out (15°>natural) and toe-in (15°

The falling body velocity is 00000 when mass and energy are interdependent. The overestimated 00000 prevails when mass and energy are separately independent. The falling time is found to be greater by a factor of 00000. A consistent account of the laws of motion from Galileo to Newton is made possible by using E = mv for conservative and dissipative systems. By the same token, the equivalence of energy and mass can be used for the mathematical assessment of gravitational waves at any velocities and not just at the speed of light. The personalized units should be replaced by the 'energy density unit' to avoid ambiguities. The key step is the application of the Hookean 'force' in conjunction with the work done as energy. The equivalence of mass and energy at any velocity were derived by using Ideomechanics, which is a mathematized verion of I-Ching. Gravitational waves are intimately related to the entanglement of multi-atom space-time. [ABSTRACT FROM AUTHOR]

Stirling engine is an external combustion engine operating on a closed regenerative cycle. The working relies on cyclic expansion and compression. The displacer which is meant for shuttling the hot gases from the displacer space may share a part of volume with the piston known as overlap volume. In this paper, an appropriate model for beta type Stirling engine is developed for optimizing its efficiency based on the swept volume ratio (SVR), i.e., theratio of swept volume of piston space to that of the displacer space. The analysis of impact of SVR on other parameters like phase angle and overlap volume has also been the part of this research. Based on the achieved results, it is observed that an optimum combination of swept volume of displacer and the piston space ensures the efficient working of the beta type Stirling engine and its efficiency increases with the increase of SVR but its impact lessens gradually as the SVR value increases by unity. The influence of phase angle and overlap volume on swept volume ratio is also investigated. The results are represented graphically. From this study, it is concluded that the required efficiency of the beta Stirling engine can be achieved by suitable combination of the discussed parameters. [ABSTRACT FROM AUTHOR]

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Abstract: The maximum swing speed of an implement is an important performance parameter in many sports. It is understood that moment of inertia (MOI) has an effect upon the swing speed of an implement and numerous studies have found a very similar relationship between swing speed and MOI. These different studies considered different movements which suggested that skill was less important than physique to this relationship. The aim of this work was to quantify the relationship between swing speed and moment of inertia and to determine whether a participant's physical characteristics are related to their swing speed performance. A series of eight visually identical rods, with varied MOI were swung in a heavily restricted, maximal motion. Feedback was supplied to the participants about their motion and all trials were recorded with a Motion Analysis Corporation motion capture system. The results found that a similar exponential relationship exists between swing speed and MOI. It was also found that a participant's maximum work done is significantly related to their swing speed. This is a relationship that could be used to predict a participant's swing speed for a specific MOI implement. More work is to be carried out on a larger population in order to be confident in the power of the relationships found. [Copyright &y& Elsevier]

The purpose of this study was to quantify the components of acceleration, load range and deceleration through a velocity spectrum during concentric hip abduction and adduction isokinetic exercise, and to investigate the effect of load range on peak torque and work done. 16 male healthy subjects performed 3 maximal concentric reciprocal hip abduction and adduction gravity corrected repetitions in a fixed order at 60, 120, 180, 240, 300, 360 and 420 ° ·s-1, with a 30 s rest between velocities. Hip abduction and adduction results revealed that load range significantly decreased while acceleration and deceleration ROM significantly increased (p < 0.05) with each increase in velocity. When the total peak torque data was corrected for load range there was a significant decrease (p < 0.05) in peak torque at velocities of 300 ° ·s-1 and above, for both hip abduction and adduction. Load range correction also resulted in a significant decrease (p < 0.05) in work done at velocities of 120 ° ·s-1 and above, for both hip abduction and adduction. The results demonstrate an inverse relationship between isokinetic velocity and load range during concentric hip abduction and adduction, and suggest a need for the clinician to carefully consider velocity selection when performing exercise on an isokinetic device. [ABSTRACT FROM AUTHOR]

In this paper, an energy-based approach to estimate the inelastic response of buildings is presented. In order to estimate torsional effects on the seismic response of structure, the associated plastic mechanism is developed in the three-dimensional model using an adapted version of the DRAIN-3DX program. The changing dynamic properties due to plastic mechanism are used for the calculation of modal lateral loads. Thus, the effects of both stiffness changes and localized response mechanisms at the structure under modal loading are included. The total input energy due to seismic loading is composed of both work done by (1) lateral force pattern acting through the translation displacement and (2) torsion acting through the rotation of each floor. For assessment of the seismic response of asymmetric buildings, the proposed procedure is shown to provide superior results compared to those obtained through deployment of the other methods commonly used: the adaptive modal combination (AMC) procedure, the modal pushover analysis (MPA), and the response history analysis (RHA) approach. [ABSTRACT FROM AUTHOR]

Abstract: The replacement of alveolar gases requires continual respiratory movements. Inspiration is active and expiration is normally passive. The lungs and chest wall recoil in opposite directions; the lungs inwards and the chest wall outwards. The recoil forces are due to the elastic properties of cartilage and muscles (chest wall) and to surface tension (lungs). The intrapleural pressure is slightly subatmospheric at functional residual capacity and becomes more negative after inspiration. During inspiration, intrapleural pressure is more negative than indicated by compliance forces alone, and during expiration, less negative. These differences reflect the extra forces required to move air through airways that have a resistance to airflow and to distort the tissues of the lung. They represent total pulmonary resistance. Work done during inspiration is required to overcome compliance and resistance forces. During expiration, the work released by the recoil of the lungs and chest wall is normally greater than that required to overcome pulmonary resistance, so expiration is passive. However, during airway constriction or rapid breathing, the forces required to produce airflow are increased and expiration becomes active. There is a gradient of intrapleural pressure from the apex to the base of the lung in an upright individual, the pressure at the apex being more subatmospheric. This means that the apical alveoli are on different regions of the compliance line. Since the compliance line of the lung is slightly curved, the fall in intrapleural pressure during inspiration causes the alveoli at the apex of the lung to be expanded less than those at the base. [Copyright &y& Elsevier]

The exploration of the disturbance of the gravitational field is an absorbing topic in physics. It might provide insight into the theory of gravitation. How is the disturbance of the gravitational field generated? What is the equation of the disturbed field? What is the relationship between the disturbance of the gravitational field due to Earth and the motion of the Moon? These problems are addressed in this paper. [ABSTRACT FROM AUTHOR]

The vortex-induced motions (VIM) of offshore floaters occur when the frequency of the vortex shedding is close to the natural frequency, and this phenomenon can severely affect the fatigue life of risers and moorings. During the design and operation stage of the semi-submersible (SS), VIM behavior has emerged as an important issue in offshore engineering. The shape of the columns, circular or square, and the wake interference, characterize the VIM of the SS. Numerical studies using the validated Detached Eddy Simulation (DES) method are carried out for parametric analysis of the VIM performance of various SS models consisting of different column shapes: with four rounded square columns, four circular columns and the mixed square-circular columns. The results show that the most significant transverse responses at 0 ∘ current incidence are observed for the SS with four circular columns and the one with two circular upstream columns. At a diamond configuration (i.e., 45 ∘ and 135 ∘), the SS models with a square upstream column all present the most pronounced VIM. The analysis shows that the vortex shedding characteristics of each column at different current incidence govern the VIM of the SS models. The square and circular columns both do large positive work on the transverse motions, and thus improve the VIM response at a certain current incidence. Therefore, the design of SS with square, circular and multi-shape columns can not mitigate the VIM behaviors efficiently. Designing a SS model with irregular polygon-shaped columns or twisted columns to avoid the strong vortex shedding may work. • Parametric study of VIM of semi-submersibles are performed numerically by DES method. • VIM behaviors of semi-submersibles vary with the column shape and configuration. • The SS models with two circular upstream columns all show the most significant VIM at 0°. • The current incidence for each column governs the VIM rather than the incidence of platform. • Square and circular columns both do large positive work on improving the VIM. [ABSTRACT FROM AUTHOR]