Prime Mover Research Articles

Age-related changes in reticulospinal contributions to anticipatory postural adjustments between back extensors and abdominal muscles.

Anticipatory postural adjustments (APAs) give feedforward postural control of the trunk, but they are delayed with ageing, affecting balance and mobility in older individuals. The reticulospinal tract contributes to postural control of the trunk; however, the extent to which age-related changes affect the reticulospinal contributions to APAs of the trunk remains unknown in humans. Here, we tested the hypothesis that a startling acoustic sound, which activates the reticulospinal tract, improves delayed APAs in older individuals. Twenty-two old (75±6years) and 20 healthy young adults (21±4years) performed a self-initiated fast bilateral shoulder flexion or shoulder extension task in response to visual, visual and auditory (80dB), or visual and startling (115dB) cues. Electromyography (EMG) was recorded from bilateral anterior deltoid (AD) and erector spinae (ES) during shoulder flexion and from bilateral posterior deltoid (PD) and rectus abdominis (RA) during shoulder extension. EMG onset of all muscles shortened during the startling cue in both age groups, suggesting a non-specific modulation of the reticulospinal tract on prime movers (AD or PD) and non-prime movers (ES or RA). Interestingly, APAs of the ES were accelerated in older participants to a similar degree as in younger participants during the startling cue. Conversely, APAs of the RA were not influenced by the startling cue in older participants. Our results suggest differential effects of ageing on functional contributions of the reticulospinal tract to APAs between back extensors and abdominal muscles.

Residential Micro-CHP system with integrated phase change material thermal energy storage

This paper presents an analysis and experimental investigation of the effect of integrating Phase Change Material (PCM) within a heat exchanger within a Micro Combined Heat and Power (Micro-CHP) system intended for residential applications. A commonly used Micro-CHP layout is replicated in a test rig to characterise the performance of two alternative heat exchanger arrangements. The first is a conventional arrangement where the exhaust gas produced by the prime mover is directed to an air-to-water heat exchanger to heat water and store it in a tank. In the second arrangement, PCM material is encapsulated within specially designed compartments in a heat exchanger to store part of the exhaust thermal energy from the prime mover while heating the water in the storage tank. The time needed to heat the water and discharge heat is compared for both cases, as well as the amount of thermal energy stored during the same operating period. The study also explored the potential to improve the designed unit by using different PCM materials. The test results show that adding 4.7 L capacity paraffin compartments within the heat exchanger extended the discharge time of the hot water by over 400 %, which reflects a marked improvement in the heat storage capacity of the system. This would result in a significant increase in the viable operating period of a CHP system. The one-dimensional analysis revealed that replacing the paraffin with ClimSel C58 PCM can reduce the charging time of the water tank by around 54 % improve the heat storage capacity by factor of 2.35 comparing to Paraffin. The proposed heat exchanger with encapsulated PCM has a potential in other applications such as storage of excess renewable energy or integration with heat pumps to improve matching of supply and demand and thus flexibility of an energy system with integrated intermittent renewables.

Optimal Rotor Design and Analysis of Energy-Efficient Brushless DC Motor-Driven Centrifugal Monoset Pump for Agriculture Applications

The agricultural sector emphasizes sustainable development and energy efficiency, particularly in optimizing water pumping systems for irrigation. Brushless DC (BLDC) motors are the preferred prime mover over induction motors due to their high efficiency in such applications. This article details the rotor design and analysis of an energy-efficient BLDC motor with specifications of 1 hp, 3000 rpm, and 48 V, specifically tailored for a centrifugal monoset pump for irrigation. The focus lies in achieving optimal energy efficiency through grey wolf optimization (GWO) algorithm in the rotor design to determine optimal dimensions of the Neodymium Iron Boron (NdFeB) magnet as well as its grade. The finite element method analysis software, MagNet, is used to model and analyze the BLDC motor. The motor parameters, such as speed, torque, flux functions, temperature, and efficiency, are analyzed. For performance comparison, the same model with different magnet models is also analyzed. Validation via 3D finite element analysis highlights improvements in magnet flux linkage, stator tooth flux density, and rotor inertia with increased magnet thickness. Simulation results affirm the consistent performance of the designed BLDC motor, preferably when efficiency is increased. This efficiency and the constant speed lead to an improvement in the overall conversion efficiency of 7% within its operating range, affirming that the motor pump system is energy-efficient.

Henry Hun and his family: Three foundational stories in the history of nineteenth-century American neurology, Part I. Thomas Hun (1808–1896): Nineteenth-century patriarch, neurophilosopher, and proto-neurologist

ABSTRACT Thomas Hun (1808–1896)—along with his sons Edward (1842–1880) and Henry (1854–1924)—were prime movers in establishing the clinical practice and academic discipline of neurology in the Hudson River Valley of New York in the ninteenth and early-twentieth centuries. This article outlines the life of the family’s semi-aristocratic patriarch, beginning with Thomas’s unusual educational background and his six-year post-graduate hiatus in Paris of the 1830s, where he came under the influence of P. C. A. Louis (1787–1872). It lays out his subsequent career as professor of the Institutes of Medicine and ultimately as dean of an American medical school that was not situated in a major metropolis. It also will demonstrate how Thomas Hun’s career as a medical practitioner, academician, neurophilosopher, and “proto-neurologist” recapitulates the evolution of clinical and academic neurology in nineteenth-century America.

Condensation shock induced in wet thermoacoustic prime mover

This Letter unveils a novel observation of condensation shock in a thermoacoustic prime mover with a wet stack, powered by a consistent 70 W heat input and maintained at atmospheric pressure. Intermittent pressure bursts, triggered by distinct acoustic cycles, reveal new characteristics of non-combustion-driven thermoacoustic instabilities, expanding the horizon beyond the energy conversion applications of traditional heat engines. Our findings, highlighted by pressure bursts reaching up to 35.8 kPa and detailed through time–frequency analysis, not only emphasize the critical role of phase-change dynamics but also pave the way for potential applications in heat transfer and material separation.

Neuromuscular Control during the Bench Press Exercise Performed with Free Weights and Pneumatic Loading

The main objective of the research was to determine neuromuscular control for different external loads, from 75% to 100% 1 RM (One Rep Max), during the flat bench press (BP) exercise performed with free weights and pneumatic loading. Despite extensive research on the internal structure of the BP exercise, few studies have examined the differences between muscular activity during the flat bench press movement between Free Weights and Pneumatic Loading. For this purpose, 10 male, trained subjects performed the BP exercise under two conditions with three different external loads (70%, 85%, and 100% 1RM), alternately with free weights and pneumatic loading. Pneumatic loading was performed on the Keiser Power Rack, where the pneumatic load was transferred as the resistance of the cables attached to the ground. EMG activity was recorded during the lifts for the following muscles: PM (Pectoralis Major), AD (Anterior Deltoid), Tblat, and TBlong (Triceps Brachii). The EMG signals were sampled at a rate of 1000 Hz. Signals were band-pass filtered with a cutoff frequency of 8 Hz and 450 Hz, after which the root-mean-square (RMS) was calculated. After completion of all the tests in a single day, 2–3 s evaluations of Maximal Voluntary Isometric Contraction (MVIC) of the prime movers in the bench press movement (AD, PM, and TBlong) were performed according to SENIAM procedures. The results of the present study indicate that pneumatic loading provides a significantly different muscle activation pattern compared to a standard bar during a heavy-loaded BP exercise. The pneumatic load was superior in activating the AD and TB muscles compared to the standard bar during the BP exercise.

Silicon Tetrachloride as innovative working fluid for high temperature Rankine cycles: Thermal Stability, material compatibility, and energy analysis

Silicon Tetrachloride (SiCl4) is proposed as a new potential working fluid for high-temperature Rankine Cycles. The capability to overcome the actual thermal stability limit of fluids commercially employed in the state-of-the-art Organic Rankine Cycles (ORC) is demonstrated by static thermal stability and material compatibility tests. Experimental static test proves its thermo-chemical stability with a conventional stainless-steel alloy (AISI 316L) up to 650 °C. A preliminary material compatibility analysis performed with optical microscope on the AISI 316L cylinder, after exposure of 300 h to SiCl4 at temperature higher than 550 °C, confirms the potentiality of this fluid when coupled with high-grade heat sources. A thermodynamic analysis has been carried out accounting for the effect of operating conditions on the axial turbine efficiency. A comparison with fluids adopted in medium–high temperature ORCs is performed, evidencing that the proposed fluid could achieve more than + 10 % points as thermal efficiency gain compared to any commercial solutions when coupled with high-temperature sources such as solar, biomass, waste heat from industrial processes and prime movers. A 2 MW SiCl4 cycle operating full-electric at 550 °C reaches a thermal efficiency of 38 %, exceeding values attainable by any other working fluid under similar conditions and power size.

Experimental investigation of fatigue for one way power transmission clutches using accelerated life tests

One way clutch (OWC) has emerged as one of the most vital devices used in heavy industries to safeguard the machines running with prime movers. It acts as a safety device to restrict the motion in the reverse direction. OWC also transmits the torque in one direction using wedge contact developed at the highly localized stress regions. The work presented consists of the development of a test bench specifically designed to simulate one way torque transmission of OWC for estimating the fatigue life based on the accelerated load tests. Accelerated load tests are performed to increase the severity within a short testing period. The microstructure disorder of the material is one the prime reasons for scattering in fatigue lives of identical batches of specimens. Therefore, several experimental tests are performed at distinct elevated load levels for different sizes of OWC. The effect of contact pressure and contact angle on fatigue lives are investigated. The fatigue life results obtained using accelerated testing correlate well with the Lundberg-Palmgren model. The load-life relationship follows the Weibull distribution. The failed ramp geometries are studied using a scanning electron microscope (SEM) to understand the governing failure mechanism for OWC.

Deep transfer learning strategy in intelligent fault diagnosis of gas turbines based on the Koopman operator

The gas turbine engine is a predominant prime mover in the transport and energy sectors, and ensuring its reliable operation holds paramount significance. While intelligent fault diagnosis (FD) approaches have seen successful advancements within the gas turbine FD landscape, many existing methods operate under the assumption of identical health states during both data collection and the FD process. Moreover, most previous studies have overlooked the diagnosis of both sensors and actuators. Another critical challenge lies in isolating simultaneous and multiple faults and providing compromising FD performance, especially in the face of continued system performance degradation. Aiming at these problems, this study develops a novel unsupervised data-driven FD strategy based on leveraging the potential of transfer learning and the Koopman operator. A deep neural network-based transfer learning framework is proposed for realizing a precise adaptive linear model called the deep transfer linear (DTL) model enabling reliable prediction of the system’s behavior in various situations and designing structured fault residuals. To this end, a deep neural network framework is used to obtain a precise Koopman model realization using the richly collected data in the source domain. Subsequently, the realized model is fine-tuned for the target domains associated with the degraded system, mitigating the adverse effects of domain shift and addressing the rich data scarcity problem in the target domain. In addition, the dedicated and generalized residual sets are designed and generated employing the geometric approach for fault isolation and a decision-making analysis is developed to diagnose simultaneous faults. The reliability of the proposed strategy is demonstrated through various experiments in the presence of noise and performance degradation, and a comparative performance analysis is conducted between the proposed strategy and another data-driven method showcasing the superiority of the proposed approach.

Voltaire’s Breadfruit

The British Government-facilitated introduction of breadfruit trees (Artocarpus altilis) from the Pacific to the Caribbean during the late eighteenth century was a notable feat of economic botany, but the identities of the earliest originators of the idea remain unclear. Previous historical scholarship has focused mainly upon the role of Joseph Banks as the prime mover behind the scheme, while more investigative scholarship has identified one of Banks’s correspondents, Valentine Morris, as having made an early suggestion of the idea in writing. This focus on Banks and Morris, however, may have overlooked or understudied even earlier origins of the idea. After discussing several key individuals involved in the inception of the breadfruit project, this article then considers a series of passages on breadfruit in the writings of Voltaire and presents a hypothetical pathway by which those involved in the actual transfer of breadfruit from the Pacific to the Caribbean, including Banks via Morris, may have been influenced by the French philosopher.

High-Density Electromyography Excitation in Front vs. Back Lat Pull-Down Prime Movers.

The current study compared the spatial excitation of the primary muscles during the lat pull-down exercise with the bar passing in front (front-LPD) or behind the neck (back-LPD) using high-density electromyography. Fourteen resistance trained men performed a front-LPD or a back-LPD within a non-fatiguing set with 8-RM as the external load. The muscle excitation centroid of latissimus dorsi, middle trapezius, pectoralis major, biceps brachii, triceps brachii and posterior deltoid muscles were recorded during the ascending and the descending phase. During the descending phase, the front-LPD showed superior excitation of the latissimus dorsi (ES = 0.97) and the pectoralis major (ES = 1.17), while in the ascending phase, the back-LPD exhibited superior excitation of the latissimus dorsi (ES = 0.63), and the front-LPD showed superior excitation of the biceps brachii (ES = 0.41) and the posterior deltoid (ES = 1.77). During the descending phase, the front-LPD showed a more lateral centroid of the latissimus dorsi (ES = 0.60), the biceps brachii (ES = 0.63) and the triceps brachii (ES = 0.98), while the centroid was more medial for the middle trapezius (ES = 0.58). The centroid of the middle trapezius was also more medial in the front-LPD during the ascending phase (ES = 0.85). The pectoralis major centroid was more cranial in the front-LPD for both the descending (ES = 1.58) and the ascending phase (ES = 0.88). The front-LPD appears to provide overall greater excitation in the prime movers. However, distinct spatial excitation patterns were observed, making exercise suitable for the training routine.

Development of High-Temperature Permanent Magnet Synchronous Motor for Autonomous Robotic Navigation: A Design and Finite Element Analysis Approach

The traditional industrial robots come with the prime mover, i.e. Electric Motors (EM) which ranges from a few hundred too few kilo watts of power ratings. However, for autonomous robotic navigation systems, we require motors which are light weighted with the aspect of high torque and power density. This aspect is very critical, when the EMs in robotic navigations are subjected to harsh high temperature survival conditions, where the sustainability of the performance metrics of the electromagnetic system of the EMs degrade with the prevailing high temperature conditions. Hence, this research work address and formulate the design methodology to develop a 630 W High Temperature PMSM (HTPMSM) in the aspect of high torque and power density, which can be used for the autonomous robotic navigation systems under high temperature survival conditions of 200°C. Two types of rotor configurations i.e. the Surface Permanent Magnet type (SPM) and the Interior Permanent Magnet type (IPM) of HTPMSM are examined for its optimal electromagnetic metrics under the temperature conditions of 200°C. The 630 W HTPMSM is designed to deliver the rated torque of 2 Nm within the volumetric & diametric constraints of D x L which comes at 80 x 70 mm at the rated speed of 3000 rpm with the survival temperature of 200°C with the target efficiency of greater than 90%. The FEM based results are validated through the hardware prototypes for both SPM and IPM types, and the results confirm the effectiveness of the proposed design methodology of HTPMSM for sustainable autonomous robotic navigation applications.

Flat-Back vs. Arched-Back Bench Press: Examining the Different Techniques Performed by Power Athletes.

Bartolomei, S, Caroli, E, Coloretti, V, Rosaci, G, Cortesi, M, and Coratella, G. Flat-back vs. arched-back bench press: Examining the different techniques performed by power athletes. J Strength Cond Res XX(X): 000-000, 2024-The International Powerlifting Federation recently changed the regulations concerning the bench press (BP) technique, not allowing an accentuated dorsal arch anymore. We investigated the difference between the flat-back vs. arched-back BP performed by competitive powerlifters as concerns the following parameters: (a) 1 repetition maximum (1RM) and barbell displacement; (b) mean and peak barbell velocity and power, and (c) the excitation of the prime movers. Fifteen highly resistance trained individuals (BP 1RM/body mass ratio: 1.38 ± 0.18) performed the flat-back and arched-back BP at their 50, 70, and 90% of the respective 1RM and performed each lift with the intent to maximally accelerate the barbell. Barbell displacement and velocity, power, and the excitation of the upper and lower pectoralis and triceps brachii were assessed. The 1RM was greater with the arched-back BP (+4.2 Kg, 95% confidence intervals + 0.0/+8.4, effect size [ES]: 0.22), whereas the barbell displacement was greater with the flat-back BP for all loads (ES from 0.40 to 0.61). Greater mean (+0.052 m·s-1, 0.016/0.088, ES: 0.42) and peak barbell velocity (+0.068 m·s-1, +0.026/0.110, ES: 0.27) were observed in the flat-back BP, whereas power did not differ. The excitation of upper and lower pectoralis was similar, while an overall trend for an increased activation of triceps brachii was noted in the arched-back vs. flat-back BP. Interestingly, no between-load difference in the excitation of upper and lower pectoralis was observed (p > 0.05). Depending on the training purposes, both flat-back and arched-back BP may be used. The present outcomes may assist practitioners and competitive powerlifters to inform training session.

Evaluating the impact of off-design CHP performance on the optimal sizing and dispatch of hybrid renewable-CHP distributed energy resources

The maturation of distributed energy resources (DER) has prompted the exploration of their deployment in commercial building applications due to their potential to supply energy at lower costs and emissions rates compared to centralized generation. While several software tools exist for evaluating the techno-economic potential of integrated renewable energy and combined heat and power (CHP) systems for distributed generation applications, many suffer from poor accuracy in capturing off-design (part load and changes in ambient air temperature and pressure) performance characteristics of microturbines, combustion turbines, or internal combustion engines. Thus, this paper presents a methodology for integrating these off-design characteristics in the mixed-integer linear program within REopt, a hybrid DER screening tool. The economic impact of the CHP off-design performance is observed through several application studies of various hybrid system configurations in different climates. Each study indicates how CHP off-design performance influences optimal sizing and dispatch decisions and therefore overall system economic value. We observe through case studies that modeling without the off-design effects, depending on the CHP prime mover and site, can result in Net Present Value predictions of hybrid systems that can be overoptimistic in frequently hot climates (up to 52 %), too conservative in frequently cold climates (up to 11 %), or unaffected (＋/−1 %) in temperate climates. Cases also highlight several advantages of hybrid systems relative to non-hybrid systems such as total economic value and the systems’ ability to mitigate potentially negative consequences attributed to off-design performance.

A Study on the Performance of the Electrification of Hydraulic Implements in a Compact Non-Road Mobile Machine: A Case Applied to a Backhoe Loader

This work presents a study of the performance of prime mover and hydraulic implement electrification in a backhoe loader. The results are validated through simulation and experimental tests. The construction and agriculture sector has grown in recent years with the aid of compact non-road mobile machines. However, as is common in fossil fuel-powered vehicles, they significantly contribute to increasing emissions. Previous research has primarily relied on powertrain electrification to address the low-efficiency drawbacks. Notably, compact off-road vehicles comprise implements less discussed in the literature. A hybrid series topology is employed, where the rear implement is driven by an electrical drive and the Diesel engine is coupled to a generator. A rule-based energy management strategy is applied. The operation of the Diesel engine and electrical machines in optimal points of the efficiency maps are the basis of the analysis. The design is validated using simulations and experimental tests in a commercial backhoe loader as a benchmark. Experimental and simulation results obtained from the hybrid series backhoe loader applied to the hydraulic implement show a 33% reduction in fuel consumption, demonstrating the effectiveness of electrification in reducing emissions and fuel consumption of compact non-road mobile machines.

P-702 Centrifugal Pump Damage Analysis Insights and Implications

Centrifugal pumps are widely used in industries for fluid transfer, operating on the rotation of an impeller driven by a prime mover. However, sudden performance drops and operational instability pose significant challenges, impacting overall system efficiency. Predictive maintenance relies on vibration analysis to assess rotating equipment condition, with vibration patterns indicating potential issues such as cavitation and corrosion. Prolonged cavitation leads to erosion of channel wall surfaces, resulting in structural damage. This study aims to address the knowledge gap in understanding the relationship between pump vibration, cavitation, and corrosion. Through comprehensive vibration analysis and examination of pump performance, our research identifies the mechanisms driving pump degradation. The findings highlight the critical role of predictive maintenance in mitigating pump failures and optimizing system performance. Highlights : Vibration analysis crucial for predictive maintenance: Identifying early signs of pump deterioration. Cavitation-induced erosion: Understanding the impact of prolonged cavitation on pump performance. Importance of proactive maintenance: Mitigating pump failures and optimizing system efficiency. Keywords : Centrifugal pumps, Vibration analysis, Cavitation, Corrosion, Predictive maintenance

Analysis of the Causes of Turbine Power Efficiency Decreases

Abstract. The steam turbine as the prime mover converts steam energy into kinetic energy and kinetic energy is further converted into mechanical energy in the form of rotation of the shaft turbine. Turbines as generator drives so as to produce electric power that can be used in various industrial fields. The energy required is large and the continuous use of the turbine must operate with sufficient stability for a long time. Turbine efficiency will decrease due to several factors such as errors during operation and duration of maintenance. Based on data obtained from PT. Synergy of Gula Nusantara PG. Kremboong turbine power efficiency will decrease because there are several factors that cause corrosion, erosion and wear and tear on turbine engine components. Steam for turbine drive produced by steam boilers containing dirt or inappropriate water ph can cause scale on the turbine so that the turbine cannot rotate optimally.

Simulation studies on the performance comparison of thermoacoustic prime mover with various resonator geometries and different stack materials

Simulation studies on the performance comparison of thermoacoustic prime mover with various resonator geometries and different stack materials

Investigating the energy storage performance in optimal design of a solar hybrid multi‐generation system with distillatory

AbstractIn this study, a cogeneration system of heating, cooling and power used with the solar flat plate collectors (FPCs) and photovoltaic panels (PVs) integrates with a multi‐effect distillation through thermal vapor compression (MEE‐TVC), investigated as the first system to meet the loads of heating, cooling, electricity and fresh water. As an innovation, the combination of the first system with cooling and thermal storage tanks have been investigated. The systems are optimized with MATLAB and single‐objective genetic algorithm. The total annual cost considered as the objective function to compare the two systems and 36 and 61 design variables are obtained for the first and second systems, respectively. The design parameters considered for optimization included the capacity of the diesel engine as the prime mover, electrical chiller capacity, absorption chiller capacity, size of the boiler, partial loads of the diesel engine for each hour of the 2 days (1 day for hot months and 1 day for cold months), partial loads of the chillers for each hour of the first days (second day has no cooling load), number of FPCs and PVs, number of effects in the desalination unit, driving steam pressure, feed water flow rate, driving steam flow rate, and electric cooling ratio. The optimization aimed to fulfill the heating, cooling, electricity, and fresh water requirements of a residential town situated in Bandar Abbas, Hormozgan province, Iran. The second system's optimization results were compared with first system. The results have shown that the objective function for the first system was and the initial investment cost was , and for the second system the objective function was and the initial investment cost was . Therefore, by using energy storage, the objective function was reduced by 11.30%.

A hybrid solar-driven vacuum thermionic generator and looped multi-stage thermoacoustically driven cryocooler system: Exergy- and emergy-based analysis and optimization

Significant high-quality heat is wasted in the vacuum thermionic generator (VTIG), which can be efficiently utilized as a prime mover of a bottoming system for cogeneration applications. For this purpose, a new environmental-friendly hybrid system composed of a heliostat solar field, VTIG, and looped multi-stage thermoacoustically driven cryocooler (LMTC) is established, in which the high-temperature heat source of the solar receiver runs the VTIG to generate power, and the LMTC recovers the waste heat of the VTIG to produce a cooling load. Thermodynamic, economic, and environmental analyses of the system are carried out based on exergy and emergy concepts. Moreover, a parametric study is performed to assess the effect of design parameters on the system's thermodynamic, economic, and environmental criteria. Finally, the multi-criteria salp swarm optimization algorithm and decision-making procedures are conducted to improve the exergetic performance and decrease the system's cost and monetary emergy rates along with the environmental impact and ecological emergy rate. Findings depict that at the reliable, optimal operation of the system, the exergetic efficiency can reach 29.36% with a maximum power of 17.2 MW and cooling load of 0.260 MW. The system's cost and monetary emergy rate can be reduced to 0.059 $/s and 5.94 × 1010 seJ/s, with 10.6% and 10% reductions, respectively. Moreover, the environmental impact and ecological emergy rates decline by 6% and 7.4%, respectively. The theoretical findings may offer guidance for the optimum designing and practical running of such a solar solid-state cogeneration system.