Cycle Parameters Research Articles

The Development Cycle of Machining Operations on an Educational CNC Machine

The paper presents a technological analysis, the phases and working methods, as well as the parameters of the processing cycle of a flange for a high-pressure hydraulic gear pump, which has the code FHP-05-12-24, made of polymeric material of ERTALON 66 SA type. The processing was made by cutting with the help of an educational milling and drilling machine with numerical control called EMCO MILL 55 CNC. The commands were programmed through a computer interface, using a conventional numerical code that commands the same kinematic chains, defining specific elements such as the geometric structure of the part, the technological conditions, the structure of the CNC kinematics, the calculation of the programmable coordinates, the parameters of the cutting tools and the parameters of the cutting regime. Based on the characteristics of the polymer material, but also on the identification of programmable functions and routines, the complete development cycle of the complex part processing operations was defined using special functions dedicated to the drilling and milling processes of the profiled surfaces. The part program structure contains program blocks associated with each stage and machining tools. The purpose of the study is to highlight, at an early stage, how students and young researchers can use computer numerical control (CNC) machines, which can be used as a support for the physical processing of complex surfaces, possibly obtained by digitizing and measuring data through a digital correlation based on specialized software products (e.g. GOM Scan, GOM Inspect, FEM analysis, etc.).

Effects of meteorology and lunar cycle on the post-thawing quality of avian sperm.

Various climatological and lunar cycle parameters have a direct impact on animal reproduction, and in the case of the avian species, spermatozoa are extremely sensitive to heat stress. These parameters could influence sperm freezability, which will ultimately affect post-thawing semen quality, being sperm motility in roosters a relevant indicator of this quality as it is highly related to fertility. Therefore, the objective of the present study is to determine which are the climatological and lunar cycle parameters that have a greater effect on sperm freezability in roosters. Sperm was obtained from 16 Utrerana breed roosters and a total of 27 replicates were performed. A pool was made with those ejaculates that met the minimum quality criteria for each replicate, and four freezing-thawing samples per replicate were analyzed. The straws were thawed, and sperm motility was evaluated, classifying the results obtained into four seminal quality groups according to the guidelines of the Food and Agriculture Organization of the United Nations (Group 1: Good, Group 2: Satisfactory, Group 3: Acceptable but undesirable and Group 4: Unsatisfactory). The following traits were recorded for each day of semen collection: maximum temperature, minimum temperature, maximum barometric pressure, minimum barometric pressure, maximum gust, wind direction, mean wind speed, sunshine hours, rainfall, moon phase, and percentage of illuminated lunar surface over the total area. A discriminant canonical analysis was performed to determine which of these parameters offered the most information when classifying an ejaculate in each quality group, with minimum temperature, the new moon as moon phase, minimum barometric pressure, and rainfall being the most significant variables. According to the results obtained, semen quality decreases when temperature and precipitation are lower, pressure is higher, and when there is a new moon phase. Therefore, these environmental conditions should be avoided for sperm collection and processing.

The effects of bathymetry on the long-term carbon cycle and CCD

The shape of the ocean floor (bathymetry) and the overlaying sediments provide the largest carbon sink throughout Earth's history, supporting ~one to two orders of magnitude more carbon storage than the oceans and atmosphere combined. While accumulation and erosion of these sediments are bathymetry dependent (e.g., due to pressure, temperature, salinity, ion concentration, and available productivity), no systemic study has quantified how global and basin scale bathymetry, controlled by the evolution of tectonics and mantle convection, affects the long-term carbon cycle. We reconstruct bathymetry spanning the last 80 Myr to describe steady-state changes in ocean chemistry within the Earth system model LOSCAR. We find that both bathymetry reconstructions and representative synthetic tests show that ocean alkalinity, calcite saturation state, and the carbonate compensation depth (CCD) are strongly dependent on changes in shallow bathymetry (ocean floor ≤600 m) and on the distribution of the deep marine regions (>1,000 m). Limiting Cenozoic evolution to bathymetry alone leads to predicted CCD variations spanning 500 m, 33 to 50% of the total observed variations in the paleoproxy records. Our results suggest that neglecting bathymetric changes leads to significant misattribution to uncertain carbon cycle parameters (e.g., atmospheric CO2 and water column temperature) and processes (e.g., biological pump efficiency and silicate-carbonate riverine flux). To illustrate this point, we use our updated bathymetry for an Early Paleogene C cycle case study. We obtain carbonate riverine flux estimates that suggest a reversal of the weathering trend with respect to present-day, contrasting with previous studies, but consistent with proxy records and tectonic reconstructions.

Impact of relative humidity variations on Carrara marble mechanical properties investigated by nonlinear resonant ultrasound spectroscopy

Like many other stones, marble mechanical properties can be significantly changed in presence of water. Water most often induces a weakening which can lead to marble degradation when coupled to temperature variations. Yet, marble artefacts are more frequently subjected to relative humidity (RH) variations than episodes of water imbibition and/or drastic temperature variations. Thus, one could wonder how do variations of RH alone impact marble mechanical state. In this study, Carrara Gioia marble samples are subjected to adsorption-desorption cycles. They were previously thermally-damaged between 40 and 105 °C, and their microstructure was characterized for each heating temperature. The evolution of their mechanical properties is monitored non-destructively with two parameters measured by Nonlinear Resonant Ultrasound Spectroscopy. The resonant frequency decreases weakly with increasing RH, indicating a diminution in sample stiffness due to low moisture-induced softening. The nonlinear parameter increases strongly, probably due to higher capillary pressure associated to a capillary condensation increase with RH. However, these phenomena are reversible: during adsorption-desorption cycling both parameters remain quite constant for a given RH. Therefore, while a RH increase impacts the mechanical properties of Carrara marble, adsorption-desorption cycling shows a reversible behavior which does not induce any permanent change in mechanical properties.

Design and simulated characterization of the dual-band polarizer based on metasurface structure

Dual-band polarizers must simultaneously exhibit high transmittance and bandwidth efficiency in fields such as polarization navigation and efficient detection. However, in most studies, the detection of dual bands is inefficient. To address this issue, we designed a dual-band polarizer similar in structure to the Roman numeral II, and it allows transmission of two different linear polarizations within different frequency bands. The interaction of the dual-band nano-polarizer with the polarization state of the incident light was analyzed through simulation experiments on the material, height, duty cycle, and other parameters of the periodic structure of the polarizer unit. The simulation results show that the proposed dual-band polarizer could achieve a polarization degree above 0.75 in the visible range and above 0.8 in the near-infrared (NIR) range. In addition, the transmittance was above 80% for x-polarization light in most of the visible wavelengths and reached 97.7% for y-polarization light in the NIR region, where NIR bandwidth accounted for 83.3% of the NIR wavelengths. The proposed design can achieve high transmittance and can be applied to ultrawide single-band polarization detection or dual-band vertical polarization detection.

Inferred drought-induced plant allocation shifts and their impact on drought legacy at a tropical forest site.

While droughts predominantly induce immediate reductions in plant carbon uptake, they can also exert long-lasting effects on carbon fluxes through associated changes in leaf area, soil carbon, etc. Among other mechanisms, shifts in carbon allocation due to water stress can contribute to the legacy effects of drought on carbon fluxes. However, the magnitude and impact of these allocation shifts on carbon fluxes and pools remain poorly understood. Using data from a wet tropical flux tower site in French Guiana, we demonstrate that drought-induced carbon allocation shifts can be reliably inferred by assimilating Net Biosphere Exchange (NBE) and other observations within the CARbon DAta MOdel fraMework. This model-data fusion system allows inference of optimized carbon and water cycle parameters and states from multiple observational data streams. We then examined how these inferred shifts affected the duration and magnitude of drought's impact on NBE during and after the extreme event. Compared to a static allocation scheme analogous to those typically implemented in land surface models, dynamic allocation reduced average carbon uptake during drought recovery by a factor of 2.8. Additionally, the dynamic model extended the average recovery time by 5 months. The inferred allocation shifts influenced the post-drought period by altering foliage and fine root pools, which in turn modulated gross primary productivity and heterotrophic respiration for up to a decade. These changes can create a bust-boom cycle where carbon uptake is enhanced some years after a drought, compared to what would have occurred under drought-free conditions. Overall, allocation shifts accounted for 65% [45%-75%] of drought legacy effects in modeled NBE. In summary, drought-induced carbon allocation shifts can play a substantial role in the enduring influence of drought on cumulative land-atmosphere CO2 exchanges and should be accounted for in ecosystem models.

Rainfall forecasting in arid regions in response to climate change using ARIMA and remote sensing

Climate changes in increasing at alarming rates which caused outward changes in the hydrological cycle parameters such as temperature and precipitation. The spatial and temporal distribution of rainfall has changed all over the world. Rainfall forecasting is considered an important tool that could help decisionmakers for managing water resources. Syria is facing several drought events that may affect its water resources. Due to the lack of available rainfall data from land stations in Syria after the civil war started in 2010 till now, one of the aims of this study is to depend on rainfall data from satellite images after correcting these data using the available land stations data. This study also aims to assess rainfall trends in Syria due to climate change and forecasting rainfall. The rainfall data were collected from 71 land stations from 1991 to 2009. Satellite images from Climate Data Record (CDR) were downloaded from 1983 to 2020 and ArcMap was used to extract rainfall data at locations of land stations. The extracted rainfall data from satellite images were corrected by land stations data from 1991 to 2009. Then Statistical Package for the Social Sciences (SPSS) program with Auto-Regressive Integrated Moving Average (ARIMA) models are used to fit and forecasting rainfall in Syria. The rainfall trends at the studied stations were analyzed for 40 years (1983–2022) and a forecast of one year is conducted. The results showed decreasing trends at all the stations that lead to a decrease the quantity of water received every year which could affect the water resources in Syria and agriculture and food security will be also affected. The results are consistent with Intergovernmental Panel on Climate Change (IPCC) reports that concluded a decrease in rainfall at southern and eastern Mediterranean regions. The results of the current study could help in the management of water resources in Syria and forecasting using ARIMA is recommended for rainfall predictions.

Robotic-arm assisted versus manual total knee arthroplasty: Functional gait analysis from a randomised controlled trial

The primary aim of this study was to assess whether measures of functional gait assessment were improved with robotic total knee arthroplasty (rTKA) when compared to manual TKA (mTKA). Gait analysis was performed as part of a randomised controlled trial. Walking and relaxed standing assessments were performed using an instrumented mat system. Spatiotemporal variables included gait cycle parameters, anteroposterior and lateral sway, and plantar pressure ratios. Measurements were recorded at pre-operative baseline and 12 months post-operatively. 100 patients were randomised, 50 to each group. Complete gait cycle data were available for 26 rTKA and 23 mTKA patients. Cadence and walking velocity showed overall improvements following surgery, with no difference between the two groups. In the operated limb, overall step and stride times decreased, while step and stride lengths increased. Subgroup analysis showed reduced propulsion time with rTKA, and decreased foot flat and mid stance times with mTKA. Lateral sway was decreased in the rTKA group. Plantar pressure ratios showed an overall increase in hindfoot loading on the operated limb, with no difference between the two groups. No other significant differences were identified between rTKA and mTKA at 12 months, and limitations may include statistical error. A small sample of the study cohort was followed up; analysis may represent the results of satisfied patients with well-functioning TKA. Further study could incorporate proprioceptive and 3D gait analysis techniques to analyse knee kinetics and kinematics with robotic surgery. Pressure mapping could further subdivide the plantar surfaces to explore any nuances in differential loading.

Research on Off-Design Characteristics and Control of an Innovative S-CO2 Power Cycle Driven by the Flue Gas Waste Heat

Recently, supercritical CO2 (S-CO2) has been extensively applied for the recovery of waste heat from flue gas. Although various cycle configurations have been proposed, existing studies predominantly focus on the steady analysis and optimization of different S-CO2 structures under design conditions, and there is a noticeable deficiency in off-design research, especially for the innovative S-CO2 cycles. Thus, in this work aimed at the proposed novel S-CO2 power cycle, off-design characteristics and corresponding control strategies are investigated for the waste heat recovery. Based on the design parameters of the S-CO2 cycle, structural dimensions of printed circuit heat exchangers (PCHEs) and shell-and-tube heat exchangers are determined, and design values of turbines and compressors are specified. On this basis, off-design models for these key components are formulated. By manipulating variables such as cooling water inlet temperature, cooling water mass flow rate, flue gas inlet temperature and flue gas mass flow rate, cycle performances of the system are analyzed under off-design conditions. The simulation results show that when the inlet temperature and the mass flow rate of cooling water vary separately, the thermal efficiency both can reach the maximum value of 28.43% at the design point. For the changes in heat source parameters, the optimum point is slightly deviated from the design condition. Amidst the fluctuations in flue gas inlet temperature, the thermal efficiency optimizes to a peak of 28.56% at 530 °C. In the case of variation in the flue gas mass flow rate, the highest thermal efficiency 28.75% can be obtained. Furthermore, to maintain the efficient and stable operation of the S-CO2 power cycle, the corresponding control strategy of the cooling water mass flow rate is proposed for the cooling water inlet temperature variation. Generally, when the inlet temperature of cooling water increases from 23 °C to 27 °C, the cooling water mass flow should increase from 82.3% to 132.7% of the design value to keep the system running as much as possible at design conditions.

Research on an optimization design method for a TBCC propulsion scheme

Abstract An optimization methodology for a TBCC propulsion schemes was established for hypersonic vehicles, focusing on the integration of aircraft and engine performance. Altitude-velocity characteristics of TBCC propulsion were obtained through engine performance calculations. By analyzing mission requirements, lift-drag characteristics, and flight constraints, the take-off thrust-weight ratio and wing load of the vehicle were optimized to meet the flight conditions. In addition, the fuel ratio was calculated. To determine the vehicle’s gross take-off weight and the engine’s take-off thrust, a model considering the weight of the vehicle and the turbine engine were used. The optimization process selects four thermodynamic cycle parameters for the turbine engine as the independent variables. An improved particle swarm optimization-back propagation neural network was used to establish the relationship between the four parameters and the gross take-off weight, aiming to minimize the vehicle’s weight. The results of the optimization process show that the total take-off weight of the optimized vehicle has decreased from 112363.41 kg to 102218.98 kg. The required uninstalled take-off thrust of TBCC has also been reduced from 162.86 kN to 147.49 kN, resulting in a decrease in mass flow from 156.50 kg/s to 133.30 kg/s.

Use of Non-Isothermal cure cycles for reducing cure induced deformation in laminated composites

The aim of the present work is to demonstrate the effectiveness of non-isothermal (multi-ramp) cure cycles to reduce process induced deformation in laminated composites over the conventional isothermal cure cycles. For that purpose, a relationship between non-isothermal cure cycle parameters and the occurrence of two physical phenomena namely modulus development and cure shrinkage are first identified. Further, the influence of these phenomena on residual stresses/deformations through the competing mechanisms of thermal and cure shrinkage effects is demonstrated. Finally, optimal non-isothermal cure cycle parameters that minimize the process-induced deformations (∼10 %) are determined by using the process model and the NSGA-II genetic algorithm.

Risk Factors Associated with Chemotherapy-Induced Nausea and Vomiting Among Women with Breast Cancer Receiving Highly Emetogenic Chemotherapy: Individual Patient-Based Analysis of Three Prospective Antiemetic Trials.

Although risk factors related to chemotherapy-induced nausea and vomiting (CINV) have been identified in previous studies, only a few studies have evaluated the risk factors associated with contemporary antiemetic prophylaxis, including olanzapine/aprepitant- or NEPA-containing regimens. This study aimed to identify the risk factors associated with CINV development in Chinese breast cancer patients receiving doxorubicin and cyclophosphamide chemotherapy. Data from 304 patients enrolled in 3 previously reported prospective antiemetic studies were included. Multivariate logistic regression models were used to predict risk factors associated with CINV occurrence. Additionally, the likelihood of treatment failure in relation to the number of risk factors in individual patients was evaluated. Multivariate analysis of the entire study group revealed that obesity status (defined as body mass index/= 25.0 kg/m2) and the use of olanzapine/aprepitant- or NEPA-containing anti-emetic regimens were associated with a high likelihood, while a history of motion sickness was associated with a lower likelihood, complete response (CR), and "no nausea" in the overall phase. A history of vomiting during pregnancy was also associated with a lower likelihood of an overall CR. Patients with an increasing number of risk factors had a higher likelihood of treatment failure and shorter time to first vomiting. Those who did not achieve CR and "no nausea" in the first cycle were less likely to achieve these parameters in the subsequent cycle of chemotherapy. The present study confirmed previously reported risk factors for CINV in Chinese breast cancer patients receiving doxorubicin and cyclophosphamide. Further optimization of CINV control is required for patients with identifiable risk factors; olanzapine/aprepitant- or NEPA- containing prophylaxis are the preferred contemporary anti-emetics regimens for Chinese breast cancer patients undergoing doxorubicin and cyclophosphamide chemotherapy.

Small-Scale Power Plants Based on Organic Rankine cycle (ORC) using Low-Boiling Fluorocarbon Working Fluids when Operating at High Initial Cycle Conditions

The purpose of the work is to develop and analyze the operation of a thermal circuit based on the organic Rankine cycle (ORC) using low-boiling working substances of the fluorocarbon class when operating at high initial cycle parameters. This goal is achieved by energy analysis of single- and multi-stage thermal circuits of power plants with a turbine circuit operating on low-boiling fluorocarbon work-ing substances, such as octafluoropropane C3F8 and decafluorobutane C4F10. It is proposed to integrate the ORC thermal circuit as an extension to a small-capacity gas turbine power plant (GTU), operating on synthesis gas after a biomass gasifier. The most important results of the work are the possibility of implementing a cycle with a low condensation temperature of the medium, which allows, when using low-boiling working fluids, to significantly reduce the temperature of the heat removal process and, consequently, increase the efficiency of the cycle. The possibility of using the listed working substances in power plants with a turbine circuit, which until now have been used mainly as refrigerants for refrig-eration and heat pump systems, has been shown. The significance of the results of the work lies in the fact that, based on the analysis of the energy complex, a circuit solution has been proposed and justified that can increase the energy efficiency of the power supply complex, increasing the volume of generated electrical power and providing a number of technological and environmental advantages.

Investigation of the part load behavior for the R-Graz cycle with pure oxygen and hydrogen fuel

ABSTRACT In order to address the future demands for large-scale and efficient hydrogen storage and utilization, while considering the need of power dispatch and peak shaving, in this article, based on the cycle part load models and the conceptual design of the main components, the R-Graz cycle design parameters have been reoptimized, and subsequently, an analysis of the part load behavior and performance characteristics was conducted. The results show that within the load range discussed in this paper, i.e., 50% to 100%, the components of the R-Graz cycle are well matched, enabling high-efficiency operation. The net cycle efficiencies are 64.4% and 71.0% for 50% and 100% load respectively. Within this wide load range, the performance of the R-Graz cycle surpasses that of the Graz cycle consistently. When the load decreases, key parameters of the R-Graz cycle’s main components, such as rotational speed, pressure, temperature, mass flow rate and split ratio also decrease. Performance analysis under varying load conditions reveals that the maximum temperature in the cycle is a critical parameter affecting the efficiency of the R-Graz cycle. The research findings of this article lay the foundation for the practical application of the R-Graz cycle.

Results of functional electrical stimulation of leg muscles during walking in a patient in the early recovery period after a stroke

Acute cerebrovascular accident throughout the world remains the main cause of subsequent disability in persons who have suffered a stroke.
 One promising area is neuromuscular stimulation. Functional electrical stimulation is a subtype of neuromuscular stimulation in which stimulation promotes functional and goal-oriented movements in the individual.
 A course of functional electrical stimulation was administered while walking to a 74-year-old patient in the late recovery period of an ischemic stroke (the right middle cerebral artery). 14 procedures were performed lasting from 20 to 30 minutes. Before and after the functional electrical stimulation course, a clinical study and a study of the biomechanics of walking were conducted.
 The results obtained showed an improvement in clinical indicators, inconsistent changes in the time parameters of the step cycle, an increase in amplitudes in the hip and knee joints, as well as normalization of the function of the knee and ankle joints of the paretic side. Functional EMG research showed both an improvement in muscle activity and normalization of their activity profile, as well as processes of function restructuring that require further study.
 During functional electrical stimulation, there were no negative reactions from the patient or irritation of the skin at the locations of the electrodes.
 The method of functional electrical stimulation requires further study and reasonable application in this category of patients.

Innovative metaheuristic algorithm with comparative analysis of MPPT for 5.5 kW floating photovoltaic system

Multiple localized maxima in power voltage features are triggered by non-uniform irradiance, which has a detrimental influence on photovoltaic (PV) system operation. Numerous control approaches for PV maximum power point tracking (MPPT) have lately been investigated. This paper proposes a metaheuristic algorithm to reach PV maximum power more efficiently based on the hybridization of Improved Grey Wolf Optimization (IGWO) and BAT algorithms, which are chosen for their reliability and fast MPPT for PV systems. However, they both encounter issues including delayed convergence and increased oscillations while tracking. To overcome these limitations, a newly Improved Grey Wolf BAT Optimization (IGWBO) is applied to specify the duty cycle parameter that is used in MPPT to enhance the performance of FPV systems under a variety of non-uniform weather scenarios. The results of implementing IGWBO-FPV are compared to those of IGWO-FPV, GWO-FPV, BAT-FPV, and FPV without any control algorithm. The findings revealed that the proposed IGWBO-FPV approach outperforms the annual generated power of the IGWO-FPV, GWO-FPV, BAT-FPV, and FPV without control by 5.64%, 10.58%, 17.54%, and 27.28% respectively. The optimal IGWBO-FPV enviro-economic evaluation indicates that 42.83 tons of CO2/year can be prevented from being released into the environment, with an LCOE of 0.052 $/kWh.

Estimation of constitutive parameters for shape memory polymer thermo-mechanical cycle by an integrated simulation and inverse optimization method

In this work, a method for inverse optimization of shape memory polymer material parameters is proposed to determine the intrinsic model parameters more quickly and accurately for simulated experimental test analysis. First, the basic mechanical properties of the material are characterized experimentally and the parameters of the generalized Maxwell model based on SMP material are fitted. Then, a joint simulation inversion optimization method is built in the ISIGHT-MATLAB-ABAQUS integrated environment to optimize the time domain Prony series parameters using downhill simplex optimization algorithm. The results show that the average errors of the stress curves before and after the optimization of the cooling solid phase and the experimental results are 0.31 MPA and 0.23 MPA, respectively, and the average errors of the strain curves in the warming recovery phase are 1.70% and 0.40%, respectively. After the inversion optimization, the average errors of the stress curves are optimized by 25.8% and the average errors of the strain curves are optimized by 76.5%. This method makes the simulation results more stable with the experimental results, which can effectively reduce the experimental cost and promote the shape memory property of SMP to be widely used in engineering.

Thermal performance enhancement of novel integrated vapor compression and organic rankine cycle for electricity production: a full-condensing vs. desuperheating approach comparison in ultra-low-grade waste heat recovery

This paper presents the thermodynamic analysis, performance assessment and working fluid selection for a novel integrated vapor compression cycle and the organic Rankine cycle system, which recovers ultra-low-temperature waste heat (50 °C) rejected by the condenser of a vapor compression cycle (VCC). The study is conducted on a vapor compression system of a 35 kW cooling capacity, followed by the component sizing of the organic Rankine cycle (ORC) based on the available waste heat in the condenser of the refrigeration system. The effect of the operational parameters of the vapor compression cycle on the overall system performance are investigated. The system performance of the integrated system is estimated in terms of coefficient of performance, cycle thermal efficiency and exergy efficiency. The novel integrated systems has been analyzed thermodynamically for 36 pairs of pure refrigerants. Results show that the working fluid pair R600a/R141b with combined coefficient of performance (3.54), ORC thermal efficiency (3.05 %), electricity saving ratio (13.34 %) and total exergy destruction (6.94 kW) is the most suitable VCC/ORC working fluid pair in full condensing method. R407c-R141b is found to be the best working fluid pair in desuperheating method for the same integrated system. The performance analysis for full condensation and desuperheating methods are also investigated. The results indicate a 12.5 % improvement in the coefficient of performance of the integrated system using the full condensation method and a 2.5 % improvement using the desuperheating method compared to the standalone air conditioning system. Additionally, the sensitivity analysis results show that there exists optimum operating condition that maximize the system performance of the integrated system.

Research on multi-objective parameter optimization of split flow dual flash thermodynamic cycle

In addition to considering the intermediate pressure variables, the split flow double flash thermodynamic cycle also needs to consider the operating conditions and split flow coefficient of the cycle. Traditional algorithms require too much computation and have a longer response time. Faced with sudden operating conditions or changes in production conditions, it is difficult to quickly re-optimize the intermediate parameters of the split flow double flash thermal cycle and carry out corresponding system control. This article uses intelligent optimization algorithms instead of global search methods to optimize multi-objective parameters in a split flow double flash thermodynamic cycle. By summarizing and analyzing the characteristics of algorithms such as SIO, EA, and ANN, it is believed that the GWO algorithm in the SIO class is the most suitable for multi-objective parameter optimization of the split flow double flash thermal cycle. It is combined with the SA optimization algorithm to propose the SA-GWO algorithm with faster optimization speed and higher optimization accuracy, taking the initial position of the wolf pack as the optimization objective. Combined with the cycle thermodynamic model, a multi-objective parameter optimization model for the split flow double flash thermal cycle is established.

Investigation of duty cycles for measuring activity in passive acoustic bat monitoring

Echolocating bats are important bioindicators that can be monitored effectively using passive acoustic monitoring (PAM) techniques. In PAM, duty-cycle-based temporal subsampling is often used to collect data at ON/OFF intervals to circumvent the limitations of recorder battery and storage capacity to enable long-term monitoring. However, potential bias introduced by temporal subsampling has not been systematically investigated for bat monitoring. Here, we use continuous audio recordings from the Union Bay Natural Area in Seattle in Summer 2022 to simulate the effects of temporal subsampling using different duty cycle parameters. We detected bat calls automatically using a deep learning model [Aodha et al., 2022, BioRxiv] and calculated three metrics as proxy for bat activity: number of calls, Activity Index (AI), and Bout Time Percentage (BTP). We found that although the number of calls and AI are more readily computable using the detected calls, BTP is likely a more accurate measure that relies less on the performance of automated call detection methods. In addition, reduced sampling for only a portion of the night (e.g., 4 hrs) was generally inadequate for capturing bat activity. Our results suggest that considering species-specific acoustic characteristics is crucial for reducing sampling bias for PAM of bats.