Nonequilibrium equations of state can provide an effective thermodynamic-like description of far-from-equilibrium systems. We experimentally construct such an equation for a direct energy cascade in a turbulent two-dimensional Bose gas. Our homogeneous gas is continuously driven on a large length scale and, with matching dissipation on a small length scale, exhibits a nonthermal but stationary power-law momentum distribution. Our equation of state links the cascade amplitude with the underlying scale-invariant energy flux, and can, for different drive strengths, gas densities, and interaction strengths, be recast into a universal power-law form using scalings consistent with the Gross-Pitaevskii model.
Hans-Peter Platzer, Anika Köck, Wolfgang Schobersberger
et al.
ABSTRACT Platzer, H-P, Köck, A, Schobersberger, W, and Dünnwald, T. Ischemic preconditioning does not improve climbing specific performance in elite athletes. J Strength Cond Res 40(1): e69-e75, 2026-The aim of the present investigation was to analyze the performance enhancing potential of an Ischemic Preconditioning (IPC) application in elite climbers and to evaluate its effects on fatigue resistance and metabolic responses. In a crossover design, female and male competitive climbers (n = 11) completed intermittent hangboard tests (8-s hanging phases alternating with 3-s passive rests until exhaustion) on 2 separate occasions (IPC/SHAM). Next to recordings of the number of completed intervals in the hangboard test, heart rate, rating of perceived fatigue (RPF), and rating of perceived exertion (RPE), measurements of blood lactate and blood gases (BGA) were performed. Near-infrared spectroscopy (NIRS) was used to examine muscular and cerebral oxygenation. The level of significance was set at p < 0.05. No differences between the 2 conditions were found for the hangboard test, RPF, RPE, and heart rate (p ≥ 0.05). Analysis of variance for BGA and NIRS variables showed no significant interaction effects except for partial pressure of oxygen and partial pressure of carbon dioxide (p < 0.05). However, these effects were not clinically relevant. As IPC was not able to elicit improved hanging performance nor alterations in other variables that would indicate a beneficial effect on recovery, there is no justification to recommend the use of IPC in elite climbing.
Roupa Agbadede, Tosin Folorunsho, Cornelius Sunday Omoniabipi
This study investigates the application of artificial neural networks for the detection of compressors fouling degradation in industrial gas turbines during operation to mitigate the loss in engine performance. An Artificial Neural Network (ANN)-based model was developed to monitor and predict compressor fouling degradation in an aero-derivative gas turbine derived from the Siemens SGT 400 class of gas turbines. Performance data from a Siemens SGT 400 gas turbine unit were obtained and used for the investigation. The obtained engine data represent all faults indicative of compressor performance. For the baseline, data were collected after maintenance actions had taken place, while the degraded case covers historical engine performance from 01 January 2013 to 28 February 2013, accounting for approximately 1,392 Equivalent Operating Hours (EOH). The dataset, encompassing variables such as temperature, pressure, gas flow, power, compressor discharge temperature, and compressor discharge pressure, was processed to eliminate irrelevant and redundant parameters before usage. A Multi-Layer Perceptron (MLP) was chosen as the architecture for the ANN. The outcomes of the training phase showed that the ANN achieved a classification accuracy of 96.2 % in proficiently distinguishing between “fouling” and "other factors" conditions. Additionally, the validation performance plot demonstrates that the network achieved its best performance with a value of 0.077507 at 18 epochs out of 24 training iterations. Finally, the confusion matrix demonstrates the model's capability to predict both fouling and non-fouling scenarios with a minimal rate of misclassification.
R. F. V. Capelleveen, M. Kenworthy, C. Ginski
et al.
Wide separation gas giant planets present a challenge to current planet formation theories, and the detection and characterisation of these systems enables us to constrain their formation pathways. The WIde Separation Planets In Time (WISPIT) survey aims to detect and characterise wide separation planetary-mass companions over a range of ages from $<5$ to $20$,Myr around solar-type host stars at distances of 75-500 (median 140) parsecs. The WISPIT survey carries out two five-minute H-band exposures with the VLT/SPHERE instrument and IRDIS camera separated by at least six months to identify co-moving companions via proper motion analysis. These two H-band observations in combination with a follow-up K_s-band observation were used to determine the colour and magnitude of the co-moving companions and to derive their masses through comparison to AMES-COND and AMES-DUSTY evolutionary tracks. We report the discovery of and two gas giant exoplanets that are co-moving with the stellar binary which itself consists of a K4 star and M5.5 star in a multi-decadal orbit. The planets are at projected separations of 338,au and 840,au and have masses of 10 and 4 respectively. We identified two common proper motion planetary companions of a (previously unknown) stellar binary with a Sun-like primary. These targets are ideal for follow-up characterisation with both ground- and space-based telescopes. Monitoring of the orbit with the GRAVITY interferometer will place constraints on their eccentricity, and spectroscopic characterisation will identify the composition and metallicity, providing information on their formation pathways.
Eftixia Chatzikamagianni, Athanasios Poulios, Alexandra Avloniti
et al.
ABSTRACT Chatzikamagianni, E, Poulios, A, Avloniti, A, Rosvoglou, A, Liakou, C, Papanikolaou, K, Stampoulis, T, Tsimeas, P, Batrakoulis, A, Chatzinikolaou, A, Draganidis, D, Jamurtas, AZ, and Fatouros, IG. Evaluation of the physiological responses and energy expenditure induced by suspension training exercises. J Strength Cond Res XX(X): 000-000, 2025-This study determined the energy expenditure and physiological responses of 6 beneficial suspension training (ST) exercises (overheads [OS], single-leg squat [SLS], torso rotations [TR], back row [BR], chest press [CP], and plank). Ten healthy young adults randomly completed both of 2 trials of ST exercises, for 30 (T30) or 45 (T45) seconds. The training load was monitored using a mobile gas analyzer, heart rate monitors, and blood lactate measurements. The total energy expenditure (TEE) (classified as the sum of oxidative [OES], glycolytic [GC], and excess postexercise energy cost [EPOC]) was estimated using the V̇o2 consumption (at rest, during exercise, and postexercise) and blood lactate (La) concentration (at rest and postexercise). The level of significance was set at p ≤ 0.05. All exercises were associated with a low-to-moderate physiological strain (rate of perceived exertion: 7.3-12.3; % of maximal heart rate: 52.3-61.7%; METs: 2.6-3.7; La: 2.2-3.9 mM; EPOC duration: 5.7-7.8 minutes), with the OS and the SLS associated with the greatest physiological/metabolic load in both trials. T45 induced a greater heart rate (53.7-61.7 %HRmax), with SLS and OS inducing the highest values. Minimal differences were noted between T30 and T45 for TEE, MET, and La values for most. EPOC had a greater contribution to TEE compared with OES and GC. Low-to moderate physiological effort during ST results in a TEE of 16.6-24.7 and 20.1-30 kcal·min-1 when performed for 30 and 45 seconds, respectively. There is a variation in TEE and physiological overload among ST exercises. Weight management exercise programs and dietary regimens need to take these finding into account.
Kuwait Energy Egypt company is currently operating Area A Field a Brownfield "since 1960" in Eastern Desert, Egypt with unique challenges for redevelopment due to their aging wells, and facilities. This paper explores effective strategies for redeveloping brownfield sites, focusing on three main challenges Infrastructural Upgrades, Reservoir Management and improve the productivity of existing wells. By using of digitalization and data Analytics, understanding, and mitigating risks in field facilities due to facilities bottlenecking, old flowlines, depleted reservoirs with sever sand production also lack of most of data of old wells, high failure rates. This paper provides insights and recommendations to guide decision-makers and practitioners involved in brownfield redevelopment projects. Area A redevelopment strategy first challenge focused on Infrastructural upgrades which required upgrading the existing infrastructure to accommodate improved production techniques by replacing old flowlines by cond. B tubing for cost optimization and construct and modern fit to propose facility at main production area at SHNW and connect all facilities to it to handle the increased production rates. Second challenge is the effective reservoir management as it is a crucial for the redevelopment strategy of Area A field to increase the extraction of oil from these depleted reservoirs by analysis of reservoir characteristics, fluid properties, and production data lead us to produce with pumps below perforations and keep eyes on sand production as well. Last and main challenge in the strategy is improving the productivity of existing wells after completing surveys on all wells with wireline to make checklist with all available data, set time frame to gather all essential missing data, develop the intervention techniques for the re-entries on the old wells with good selection for qualified vendors in critical services like fishing service and materials suppliers, and by applying innovative technologies in well completions to overcome high artificial lift failures frequency environment as a result of wells harsh conditions like using OTP "Unconventional Oversized SRP" and high clearance pump also the integration of digital technologies and data analytics in failure analysis plays a significant role in redevelopment strategy. The redevelopment strategy of Area A has several outcomes such as increased oil recovery from the existing wells from 2000 BOPD till reaching 6500 BOPD, Extended field life by applying innovative reservoir management strategies and technologies result in reduction of well failures and enhanced MTBF more than 415 days and 1.3-day MTTR in 2023. The optimization of existing infrastructure including wells, pipelines, and processing facilities lead to increased operational efficiency, reduced maintenance costs, and improved safety standards. By exploring the strategies outlined in this paper, stakeholders can make informed decisions and successfully redevelop brownfield sites in the oil and gas industry.
Abstract McCarthy, SF, McKie, GL, Howe, GJ, Vanderheyden, LW, and Hazell, TJ. Metabolic effects of reduced volume sprint interval training during and postexercise. J Strength Cond Res 38(5): 891–897, 2024—It is unclear what dose of sprint-interval training exercise (exercise volume) is required to derive beneficial metabolic effects during and postexercise. Therefore, we examined how reducing the volume of sprint interval training (SIT) from 2 minutes of “all-out” efforts (8 bouts) to 1.5 minutes (6 bouts) and 1 minute (4 bouts) affected during and postexercise metabolism. Fourteen recreationally active males (age: 25 ± 3 years; body mass index: 25.1 ± 3.1 kg·m−2) had gas exchange measured during and following (3 h) 4 experimental sessions: (a) no-exercise control (CTRL), (b) 8 × 15 SIT (2 minutes exercise), (c) 6 × 15 minutes SIT (1.5 minutes exercise), and (d) 4 × 15 SIT (1 minute exercise). All SIT protocols were 15 seconds “all-out” running efforts with 2 minutes recovery (4, 6, or 8 bouts). Changes were considered important if p 2.98) and greater than CTRL (p 2.12); however, the rate of O2 consumption (L·min−1) was similar between protocols (p = 0.479, ηp2 = 0.055). Total V̇o2 (L) postexercise was elevated following all conditions compared with CTRL (p 1.25). Overall session V̇o2 was different in each condition (p 1.89). Fat oxidation was elevated postexercise following all SIT protocols compared with CTRL (p 0.98) with no differences between protocols (p > 0.566, d < 0.48). Our results suggest reducing the number of all-out 15 seconds bouts during a SIT session from 8 to 6 or 4 had no differential effects on postexercise metabolism and differences during exercise were due to the longer duration of exercise.
Christopher J. Ho, Simon M. Fischer, Gevorg Martirosyan
et al.
We revisit the classic Joule-expansion experiments, now with a quantum-degenerate atomic Bose gas. In contrast to the classical-gas experiments, where no temperature change was measured, here we observe and quantitatively explain both cooling and heating effects, which arise, respectively, due to quantum statistics and inter-particle interactions.
Thermodynamic functions of the ideal Fermi gas at arbitrary temperatures are calculated using the standard Fermi-Stoner functions. The properties of the Fermi-Stoner functions are analyzed. The limiting cases of low-temperature and classical limits with taking into account quantum corrections and the special case of zero chemical potential are considered.
Abstract Mitchinson, CJ, Best, S, Caruso, J, and Bollinger, LM. Cardiorespiratory responses to flywheel-based inertial training squats with varying moments of inertia. J Strength Cond Res 39(3): 300–306, 2025—Flywheel-based inertial training (FIT) has gained popularity as a means to enhance muscle hypertrophy. Other applications, such as aerobic exercise training, remain unexplored. The aim of this study was to determine the cardiorespiratory responses to acute FIT with varying moments of inertia (MOIs). Overall, 20 (10 M, 10 F) healthy, physically active subjects underwent maximal graded exercise testing and completed 3 bouts of FIT exercise (1 familiarization session and 2 identical data collection sessions). Subjects completed quarter squats (60° peak knee flexion) at a pace of 50 squats·minute−1 until volitional fatigue. Flywheel-based inertial training MOI was increased by 0.005 kg·m2 every 3 minutes until a final workload of 0.020 kg·m2. Heart rate and gas exchange data were collected continuously and averaged over the final 60 s of each stage. Data were analyzed by a linear mixed model. During the final testing session, there was a main effect of MOI to increase heart rate (HR), V̇o2, and RER. Men displayed greater oxygen consumption, but a similar %V̇o2peak compared with women. We noted a significant inertia × sex interaction where RER tended to be lesser in women at higher MOI. In the final stage of exercise (MOI: 0.020 kg·m2), HR and V̇o2 were approximately 75–80 and 55% of peak, respectively, and RER was approximately 0.95–1.00. FIT quarter squats elicit moderate HR and V̇o2 responses, but near-maximal RER suggests a novel metabolic training stimulus. This exercise may supersede the lactate threshold and may not be sustainable for prolonged times. The physiological and performance effects of training in this manner are unclear.
Pablo R Fleitas-Paniagua, Rafael de Almeida Azevedo, Mackenzie Trpcic
et al.
Abstract Fleitas-Paniagua, PR, de Almeida Azevedo, R, Trpcic, M, Murias, JM, and Rogers, B. Combining near-infrared spectroscopy and heart rate variability derived thresholds to estimate the critical intensity of exercise. J Strength Cond Res 38(1): e16–e24, 2024—Critical intensity determination often requires costly tools and several testing sessions. Alternative approaches display relatively large individual variation. Therefore, simpler estimations with improved precision are needed. This study evaluated whether averaging the heart rate (HR) and oxygen uptake (V̇O2) responses associated with the muscle deoxyhemoglobin concentration breakpoint ([HHb]BP) and the heart rate variability (HRV) given by the detrended fluctuation analysis second threshold (HRVT2) during ramp incremental (RI) test improved the accuracy of identifying the HR and V̇O2 at the respiratory compensation point (RCP). Ten female and 11 male recreationally trained subjects performed a 15 W·minute−1 RI test. Gas exchange, near-infrared spectroscopy (NIRS), and RR interval were recorded to assess the RCP, [HHb]BP, and HRVT2. Heart rate (mean ± SD: 158 ± 14, 156 ± 13, 160 ± 14 and, 158 ± 12 bpm) and V̇O2 (3.08 ± 0.69, 2.98 ± 0.58, 3.06 ± 0.65, and 3.02 ± 0.60 L·minute−1) at the RCP, [HHb]BP, HRVT2, and HRVT2&[HHb]BP average (H&HAv), respectively, were not significantly different (p > 0.05). The linear relationship between H&HAv and RCP was higher compared with the relationship between [HHb]BP vs RCP and HRVT2 vs RCP for both HR (r = 0.85; r = 0.73; r = 0.79, p > 0.05) and V̇O2 (r = 0.94; r = 0.93; r = 0.91, p > 0.05). Intraclass correlation between RCP, [HHb]BP, HRVT2, and H&HAV was 0.93 for V̇O2 and 0.79 for HR. The [HHb]BP and the HRVT2 independently provided V̇O2 and HR responses that strongly agreed with those at the RCP. Combining [HHb]BP and the HRVT2 resulted in estimations of the V̇O2 and HR at the RCP that displayed smaller variability compared with each modality alone.
B. G. Prashantha, S. Seetharamu, G. S. V. L. Narasimham
et al.
AbstractIn this paper, the design and analysis of 500 W thermoacoustic refrigerators for the temperature difference of 28 K using helium and air are discussed. Helium is the best working gas, but air is chosen to study the possibility of replacing helium for the future cost-effective refrigerator since it is much cheaper than helium. Heat and work flow equations of thermoacoustic refrigerators are discussed. The refrigerator models are optimized by normalizing the design parameters using Rott’s linear thermoacoustic theory. The effect of gas spacing expressed in terms of the thermal penetration depth in stack-heat exchanger unit at 85% porosity is discussed. The effect of the resonance frequency of air on the stack-heat exchanger sheets spacing and thickness and on the theoretical performance is discussed. The effect of the resonance frequency of air on the theoretical performance at 200 Hz, 300 Hz, and 400 Hz is discussed. The cooler shows better COP of 1.72 at 300 Hz for air and 1.53 at 400 Hz for helium. The theoretical results are compared with the DeltaEC software results. The DeltaEC predicts cooling power and COP of 347 W at 1.02 for helium and 224 W at 0.79 for air, respectively.
Abstract Bitel, M, Keir, DA, Grossman, K, Barnes, M, Murias, JM, and Belfry, GR. The effects of a 90-km outdoor cycling ride on performance outcomes derived from ramp-incremental and 3-minute all-out tests. J Strength Cond Res 38(3): 540–548, 2024—The purpose of this study was to determine whether laboratory-derived exercise intensity and performance demarcations are altered after prolonged outdoor cycling. Male recreational cyclists (n = 10; RIDE) performed an exhaustive ramp-incremental test (RAMP) and a 3-minute all-out test (3MT) on a cycle ergometer before and after a 90-km cycling ride. RAMP-derived maximal oxygen uptake (V̇O2max), gas exchange threshold (GET), respiratory compensation point (RCP), and associated power output (PO), as well as 3MT-derived critical power (CP) and work performed above CP, were compared before and after ∼3 hours of outdoor cycling. Six active men served as “no-exercise” healthy controls (CON), who, instead, rested for 3 hours between repeated RAMP and 3MT tests. During the 90-km ride, the duration within the moderate-intensity, heavy-intensity, and severe-intensity domains was 59 ± 24%, 40 ± 24%, and 1 ± 1%, respectively. Compared with pre-90 km, post-RAMP exhibited reductions in (a) V̇O2max (4.04 ± 0.48 vs. 3.80 ± 0.38 L·min−1; p = 0.026) and associated PO (392 ± 30 W vs. 357 ± 26 W; p = 0.002); (b) the V̇O2 and PO at RCP (3.49 ± 0.46 vs. 3.34 ± 0.43 L·min−1; p = 0.040 and 312 ± 40 W vs. 292 ± 24 W; p = 0.023); and (c) the PO (214 ± 32 W vs. 198 ± 25 W; p = 0.027), but not the V̇O2 at GET (2.52 ± 0.44 vs. 2.44 ± 0.38 L·min−1; p = 0.388). Pre-90 km vs. post-90 km 3MT variables showed reduced W′ (9.8 ± 3.4 vs. 6.8 ± 2.6 kJ; p = 0.002) and unchanged CP (304 ± 26 W and 297 ± 34 W; p = 0.275). In the CON group, there were no differences in V̇O2max, GET, RCP, W′, CP, or associated power outputs (p > 0.05) pre-to-post 3 hours of rest. The preservation of critical power demonstrates that longer-duration maximal efforts may be sustained after long-duration cycle. However, shorter sprints and higher-intensity efforts eliciting V̇O2max will exhibit decreased PO after 3 hours of a predominantly moderate-intensity cycle.
C. Hingrand, Nicolas Olivier, Adrien Combes
et al.
Abstract Hingrand, C, Olivier, N, Combes, A, Bensaid, S, and Daussin, FN. Power is more relevant than ascensional speed to determine metabolic demand at different gradient slopes during running. J Strength Cond Res 37(11): 2298–2301, 2023—Trail running is characterized by successive uphill and downhill running sessions. To prescribe training intensity, an assessment of maximal running capacity is required. This study compared 2 uphill incremental tests using the same ascensional speed increment to identify the influence of the slope gradient on performance. Ten subjects (8 men and 2 women) performed 3 incremental exercises on various slope (1%: IT01, 10%: IT10, and 25%: IT25), and the ascensional speed increment was similar between IT10 and IT25 (100 m·h−1 every minute). Gas exchanges, heart rate, and power were monitored continuously during the tests. Similar V̇o2max levels were observed in the 3 conditions: 68.7 ± 6.2 for IT01, 70.1 ± 7.3 for IT10, and 67.6 ± 7.0 for IT25. A greater maximal ascensional speed was reached in the IT25 (1760 ± 190 vs. 1,330 ± 106 for IT25 and IT10, respectively, p < 0.01). A significant relationship was observed between relative V̇o2 levels and relative power without any effect of slope. Power should be the parameter used for prescribing training intensity compared with ascensional speed in trail.
Abstract Kipp, K and Kim, H. Muscle-specific contributions to vertical ground reaction force profiles during countermovement jumps: case studies in college basketball players. J Strength Cond Res 37(7): 1523–1529, 2023—The purpose of this study was to determine muscle-specific contributions to various types of vertical ground reaction force (vGRF) profiles in collegiate basketball players. Players from a men's (n = 5; height: 1.84 ± 0.14 m; mass: 92.8 ± 11.4 kg) and a women's (n = 5; 1.71 ± 0.09 m; mass: 80.1 ± 17.6 kg) basketball team completed 3–5 countermovement jumps (CMJ) while motion capture and force plate data were recorded. Muscle-specific contributions to vGRF were calculated through vGRF decomposition analysis. Profiles of vGRF were analyzed based on the presence of unimodal or bimodal peaks during the CMJ. The results showed that the soleus (SOL), gastrocnemii (GAS), vastii (VAS), and gluteus maximus (GMX) muscles all contributed to upward vGRF generation throughout the entire CMJ duration. The contributions were greatest for the SOL (1.78 body weight [BW]), intermediate for the GAS (0.96 BW) and VAS (0.72 BW), and negligible for the GMX (0.11 BW). For unimodal vGRF profiles, SOL contributions coincided with peak vGRF, whereas VAS contributions were stable throughout most of the CMJ. For bimodal vGRF profiles, SOL and VAS contributions explained the presence of the first vGRF peak, whereas GAS and VAS contributions explained the second vGRF peak. Differences between vGRF profiles appear to be the result of distinct force contributions from the VAS muscle, which may have implications for the analysis of vGRF time series data during CMJ testing.
Advanced techniques capable of early, rapid, and nondestructive detection of the impacts of drought on fruit tree and the measurement of the underlying photosynthetic traits on a large scale are necessary to meet the challenges of precision farming and full prediction of yield increases. We tested the application of hyperspectral reflectance as a high-throughput phenotyping approach for early identification of water stress and rapid assessment of leaf photosynthetic traits in citrus trees by conducting a greenhouse experiment. To this end, photosynthetic CO2 assimilation rate (Pn), stomatal conductance (Cond) and transpiration rate (Trmmol) were measured with gas-exchange approaches alongside measurements of leaf hyperspectral reflectance from citrus grown across a gradient of soil drought levels six times, during 20 days of stress induction and 13 days of rewatering. Water stress caused Pn, Cond, and Trmmol rapid and continuous decline throughout the entire drought period. The upper layer was more sensitive to drought than middle and lower layers. Water stress could also bring continuous and dynamic changes of the mean spectral reflectance and absorptance over time. After trees were rewatered, these differences were not obvious. The original reflectance spectra of the four water stresses were surprisingly of low diversity and could not track drought responses, whereas specific hyperspectral spectral vegetation indices (SVIs) and absorption features or wavelength position variables presented great potential. The following machine-learning algorithms: random forest (RF), support vector machine (SVM), gradient boost (GDboost), and adaptive boosting (Adaboost) were used to develop a measure of photosynthesis from leaf reflectance spectra. The performance of four machine-learning algorithms were assessed, and RF algorithm yielded the highest predictive power for predicting photosynthetic parameters (R2 was 0.92, 0.89, and 0.88 for Pn, Cond, and Trmmol, respectively). Our results indicated that leaf hyperspectral reflectance is a reliable and stable method for monitoring water stress and yield increase, with great potential to be applied in large-scale orchards.