Relative Velocity Research Articles

The Impact of Rest Intervals on the Force–Velocity Relationship Obtained During the Keiser’s 10-Repetition Leg Press Test

Background: The Keiser 10-rep leg press test protocol employs short inter-repetition rest intervals (2–38 s), raising concerns as to whether athletes perform optimally. Objectives: The aim of this study was to compare the results of the standard Keiser protocol with an identical protocol modified to include a significantly longer inter-repetition rest intervals and to evaluate whether these effects differed between men and women. Methods: A total of 30 athletes (age 17.1 ± 0.9 years, height 177.8 ± 8.8 cm, and body mass 71.9 ± 11.3 kg) performed three separate tests (total of ~900 repetitions) in a Keiser A420 leg press machine, separated by 4 to 8 days. Test day 1 included a 1RM test followed by a 10-repetition force–velocity test with a standard rest intervals. Test days 2 and 3 involved the same test, with either standard short rest intervals or fixed 3 min inter-repetition rest intervals. Results: Increasing inter-repetition rest intervals significantly improved V0 and Pmax for men and V0 and FVslope for women. The benefits of longer rest were notably more pronounced in men, particularly at light to moderate loads, where standard Keiser rest intervals are short (2–9 s). However, extending rest intervals beyond approximately 30 s, as applied at higher loads, provided no additional advantages. Conclusions: Longer rest intervals improved force–velocity metrics more in men than women, with the effect being most pronounced at light to moderate loads where standard protocols utilize short rest intervals (2–9 s). These findings suggest that women recover faster than men under these conditions. However, extending rest beyond 30 s at higher loads provides no additional benefits and is counterproductive at maximal loads.

Factors Influencing the Use of Shave Biopsy for Lesions Suspicious of Melanoma in Australia: An Exploratory Mixed-Methods Study.

Recent Australian trends indicate that shave biopsies for diagnosing lesions suspicious of melanoma are increasing, yet reasons for this remain relatively unknown. We sought to understand which factors influence Australian clinicians' use of shave biopsy for managing thin lesions suspicious of melanoma in sites of low cosmetic sensitivity. We used a convergent, exploratory mixed-methods design, with a cross-sectional online survey (n = 59) and semi-structured qualitative interviews (n = 15). We recruited clinicians working in skin cancer medicine across Australia, mostly general practitioners (> 80%) with some dermatologists (n = 7 survey and n = 1 interview participant). Survey participants indicated how frequently they used shave biopsies and rated the importance of factors when considering the use of a shave biopsy. Interview participants elaborated on the motivating factors for using different biopsy techniques. Qualitative data were professionally transcribed and analysed with content analysis. Most survey participants (95%) reported that identifying fewer signs of locally advanced melanoma was 'very important' for using shave biopsy. Fifty per cent of survey participants also reported that faster procedure speed and greater convenience were 'very important' reasons for using shave biopsy. Procedure speed was particularly important for using shave biopsy among clinicians self-identifying as time-poor. Interview participants noted (a) the risk of transecting the lesion base or (b) incomplete lesion removal from shave biopsies as reasons against their use. The relative speed and convenience of shave biopsies in clinical practice are strong motivators for their use. Further evidence on patient outcomes with widespread use of shave biopsy is required to inform clinical guidelines.

Topologies of Nanoscale Droplets upon Head-On Collision from Large Molecular Dynamics Simulations.

The binary collision of nanoscale droplets is studied with molecular dynamics simulation for droplets consisting of up to 2 × 107 molecules interacting via a truncated and shifted form of the Lennard-Jones potential. Considering head-on collisions of droplets with a temperature near the triple point that occur in a saturated vapor of the same fluid, this work explores a range of collision topologies. Four droplet sizes, with a radius ranging from 30 to 120 molecule diameters, are simulated with a varying initial relative collision velocity, covering 36 cases in total. Due to the relatively large size of the droplets, this study aims to resolve the differences in the collision behavior between droplets on the micro- and on the macroscale. By analyzing various metrics of the impact, four distinct collision regimes are found: coalescence, stable collision, holes and shattering. Coalescence, observed at low Weber and Reynolds numbers, is the formation of a stable droplet without significant deformations of the merging objects. Stable collisions, characterized by the formation of one stable droplet with notable deformations during collision, occur within a Weber number range between 10 and 505. The holes regime is only observed for droplet radii greater than 30 molecule diameters and a Weber number between 505 to 750, while collision cases surpassing this Weber number fall into the shattering regime, resulting in the breakup into satellite structures.

Airborne pollen concentrations overpass expectations in the tropical city of Medellín, Colombia.

Aerobiology in the tropics is still a science in development, where very little about their dynamics is known. Airborne pollen concentrations in the city of Medellín (Colombia) were measured using a Hirst-type sampler and correlated with meteorological parameters (relative humidity, rainfall, temperature, wind speed, and wind direction, this last analyzed by using circular statistics). Sampling was conducted over three years (2019-2022), and pollen grains were detected on all days of sampling, at higher concentrations than expected for tropical conditions. The highest pollen concentrations were observed from December to January and July-August, corresponding to the months with the lowest rainfall, which sheds light about how La Niña phenomena influenced pollen concentrations during the sampling period. The Main Pollen Season (MPS) ranged in length from 277 to 342days. The highest intra-diurnal peaks pollen concentrations occurred around noon, whilst something very different and rarely reported occurs with Cecropia, which is much more abundant at night, from 20:00 to 1:00h. Circular statistics revealed statistically significant wind direction patterns from SW, matching the same intra-diurnal pollen variations. This work helps to complete the blurred situation of the Aerobiology in the Neotropics and the dynamics of particles in the tropical atmosphere, being a first step towards the construction of pollen calendars to help pollen sufferers to mitigate symptoms.

Dissecting inertial clustering and sling dynamics in high-Reynolds number particle-laden turbulence

We advance the understanding of inertial clustering and the role of sling events in high-Reynolds number (Re) particle-laden turbulence. To this end, we perform one-way coupled particle tracking in flow fields obtained from direct numerical simulations (DNS) of forced homogeneous isotropic turbulence. Additionally, we examine the impact of filtering utilized in large eddy simulations by applying a sharp spectral filter to the DNS fields. Our analysis reveals that while instantaneous clustering through the centrifuge mechanism explains clustering at early times, the path history effect—the sampling of fluid flow along particle trajectories—becomes important later on. The filtered fields expose small-scale fractal clustering that cannot be predicted by the instantaneous flow field. We show that there exists a filter-effective Stokes number that governs the degree of fractal clustering and preferential sampling, revealing scale-similarity in the spatial distributions and fractal dimensions. Sling events are prevalent throughout our simulations and impose prominent patterns on the particle fields. In pursuit of investigating the sling dynamics, we compute the relative velocity, averaged over proximal neighboring particles, to identify particles undergoing caustics. As postulated in recent theories, we find that in fully resolved, high-Re turbulence, sling events occur in thin sheets of high strain, situated between turbulent vortices. This behavior is driven by rare, extreme events of compressive straining, manifested by characteristic fluctuations of the flow velocity gradients.

The magnitude of Ascochyta blight of chickpea and its relationship with prevailing environmental conditions in the Thal region of Punjab, Pakistan

This study assessed Ascochyta blight disease in chickpea across five districts in the ‘Thal’ region of Punjab, Pakistan: Bhakkar, Jhang, Layyah, Muzaffargarh, and Mianwali. The disease prevalence, incidence, and severity were recorded over two consecutive years, 2020-2021 and 2021-2022, during the chickpea-growing season. Disease prevalence ranged from 76% in Layyah to 40% in Muzaffargarh. Layyah also exhibited the highest disease incidence (84.2%) and severity (59.41%), while Muzaffargarh recorded the lowest disease incidence (20.55%) and severity (8.55%). All thirty-seven fungal isolates obtained from diseased samples were morphologically identified as Ascochyta rabiei. Twenty-five isolates, including five representatives from each district, were characterized based on their pathogenicity. The isolate ARL1 from Layyah exhibited the highest pathogenicity, with disease rating scores of 8.5 in detached leaf assays and 7.3 in attached leaf assays. Pathogen virulence showed a positive relationship with the disease intensity observed in the respective districts. Disease incidence and severity were further correlated with various prevailing environmental factors in these districts. Disease incidence was positively correlated with relative humidity and wind speed, while disease severity showed a positive correlation with relative humidity and rainfall but a negative correlation with maximum temperature. Other epidemiological factors did not exhibit significant relationships with the disease. This study concludes that the ‘Thal’ region is highly threatened by Ascochyta blight disease due to relatively higher relative humidity, rainfall, wind speed, and fungal virulence. Therefore, proper and timely management practices are essential to mitigate the impact of Ascochyta blight disease and address these influencing factors effectively.

New Torsional Surface Elastic Waves in Cylindrical Metamaterial Waveguides for Sensing Applications.

In this paper, we demonstrate that torsional surface elastic waves can propagate along the curved surface of a metamaterial elastic rod (cylinder) embedded in a conventional elastic medium. The crucial parameter of the metamaterial rod is its elastic compliance s44(1)ω, which varies as a function of frequency ω analogously to the dielectric function εω in Drude's model of metals. As a consequence, the elastic compliance s44(1)ω can take negative values s44(1)ω<0 as a function of frequency ω. Negative elastic compliance (s44(1)ω<0) enables the emergence of new surface states, i.e., new types of surface elastic waves. In fact, the proposed torsional elastic surface waves can be considered as an elastic analog of Surface Plasmon Polariton (SPP) electromagnetic (optical) waves propagating along a metallic rod (cylinder) embedded in a dielectric medium. Consequently, we developed the corresponding analytical equations, for the dispersion relation and group velocity of the new torsional elastic surface wave. The newly discovered torsional elastic surface waves exhibit virtually all extraordinary properties of their electromagnetic SPP counterparts, such as strong subwavelength concentration of the wave energy in the vicinity of the cylindrical surface (r=a) of the guiding rod, very low phase and group velocities, etc. Therefore, the new torsional elastic surface waves can be used in: (a) near-field subwavelength acoustic imaging (super-resolution), (b) acoustic wave trapping (zero group and phase velocity), etc. Importantly, the newly discovered torsional elastic surface waves can form a basis for the development of a new generation of ultrasonic sensors (e.g., viscosity sensors), biosensors, and chemosensors with a very high mass sensitivity.

Configuration synthesis and screening method for magnetic gear two-speed transmission for electric vehicles

Magnetic field modulated gears have contactless, lubrication-free and highly flexible transmission characteristics, which provide an inherent technological advantage in solving the vibration, jerk and lubrication problems of two-gear transmissions in electric vehicles. To this end, a magnetic gear two-speed transmission drive concept is proposed, and a configuration preference method for two-speed transmissions based on weighted directed topology maps is investigated. A directed weighted graph modulo adjacency matrix and topological evolution rules describing the structure of the system are established. Adjacency matrix ergodic evolution and isomorphism discrimination are investigated for single and two-stage magnetic gear two-speed transmissions, respectively. Through the constructed relative speed link identification algorithm, the speed ratio between any component is calculated quickly. A configuration preference method was established for the defined evaluation objectives via hierarchical analysis. Finally, a prototype was built based on the screening results. The test results showed that the optimal solution could accurately meet the design requirements and realize two-speed transmission. The accuracy of the configuration and screening method of the magnetic gear two-speed transmission system proposed in this article is verified. It provides a theoretical reference for the design of high-performance magnetic gear two-speed transmission.

Study on jet dynamic impact performance under the influence of standoff

Due to the sensitivity of the shaped charge jet to standoff and the complexity of its impact under lateral disturbances, this study aims to investigate the dynamic impact evolution of the jet influenced by standoff and lateral disturbances. A finite element model for the dynamic impact of shaped charge jets was established. Dynamic impact experiments were designed and conducted to validate the effectiveness of the numerical simulations. Utilizing dimensional analysis, a predictive model was developed for jet dynamic impact considering the combined effects of target plate strength, standoff and lateral disturbances. The results indicate that as the standoff varies between 90 mm and 225 mm, the dynamic impact depth of the jet decreases approximately linearly with increasing standoff. Meanwhile, for lateral disturbance velocities ranging from 100 m/s to 400 m/s, the impact depth decreases exponentially with increasing lateral relative velocity of the target. The lateral disturbance velocity is identified as the primary factor influencing jet impact, while the standoff is a secondary factor. The agreement among computational results, numerical simulations, and experimental outcomes confirms the accuracy and effectiveness of the predictive model and simulations, providing a basis for evaluating the dynamic impact potential of shaped charges.

Portions of the force–velocity relationship targeted by weightlifting exercises

We compared the force–velocity (F–V) characteristics between jump squat (JS) and weightlifting (hang clean [HC] and HC pull [HCP]) to determine lower limb F−V portions targeted by weightlifting exercises. Ten weightlifters performed JS at 0% (body weight only) to 70% of their one-repetition maximum (1RM) for back squat, and HC and HCP at 30‒90% and 30‒110% of their 1RM for HC, respectively. Force and velocity values at each relative load were plotted to determine the F–V features of JS, HC, and HCP. Linear regression was used to evaluate each participant’s JS F–V results to obtain individual F–V relationships. Regression equations evaluated the JS force at a given velocity for each relative load of HC and HCP. HC produced significantly less force than JS at given velocities for 30%, 40%, and 50% 1RM. Furthermore, HCP produced significantly less force than JS at a given velocity for 30% 1RM and exhibited less force than JS at a given velocity for 40% 1RM with moderate effect size. HC and HCP produce comparable forces to JS within the velocity ranges of 60‒90% and 50‒110% 1RM, respectively. Thus, weightlifting exercises target low‒moderate-velocity portion of the lower limb F–V relationship.

Distributed strategies for pursuit-evasion of high-order integrators

This paper presents decentralized solutions for pursuit-evasion problems involving high-order integrators with intracoalition cooperation and intercoalition confrontation. Distinct error variables and hyper-variables are introduced to ensure the control strategies to be independent of the relative velocities, accelerations and higher order information of neighbors. Consequently, our approach only requires agents to exchange position information or to measure the relative positions of the neighbors. The distributed strategies take into consideration the goals of intracoalition cooperation or intercoalition confrontation of the players. Furthermore, after establishing a sufficient and necessary condition for a class of high-order integrators, we present conditions for capture and formation control with exponential convergence for three scenarios: one-pursuer-one-evader, multiple-pursuer-one-evader, and multiple-pursuer-multiple-evader. It is shown that the conditions depend on the structure of the communication graph, the weights in the control law, and the expected formation configuration. Finally, the effectiveness of the proposed algorithm is demonstrated through simulation results.

Regressão Logística entre Poluição do Ar e Mortalidade por Doenças Respiratórias em Santa Gertrudes, SP (2014-2023)

Air pollution is a critical environmental problem that affects human health in many regions around the world. In cities with intense industrial activity, such as Santa Gertrudes, SP, the concentration of particulate matter, such as PM10, can have significant impacts on the respiratory health of the population. This study aims, using advanced statical modeling, to investigate the relationship between PM10 concentration and mortality from respiratory diseases. The main objective was to apply generalized linear models, specifically logistic regression, to analyze how the concentration of PM10 influences the mortality of patients hospitalized for respiratory diseases in the city of Santa Gertrudes during the period from 2014 to 2023. The methodology involved building and comparing several logistic models to assess the effect of PM10 and additional variables on mortality, such as relative humidity and wind speed. The quality of the models was assessed using the Akaike information criterion (AIC) and deviance. The results showed that PM10lag4 and “days of hospitalization” were the most statistically significant variables. The odds ratio associated with PM10lag4 indicated an increase of approximately 0.8% in the chance of death for each 1 µg/m³ increase in PM10 concentration. The variable “days of hospitalization” increased the chance of death by around 6.7% per additional day of hospitalization, highlighting the need for public policies aimed at reducing pollution and properly managing health conditions in the region.

Study on Interlayer Interface Deterioration of Double-Block Ballastless Track in Humid and Hot Environments Based on Acoustic Emission Technique

The deterioration of the interlayer interface of a double-block ballastless track is affected by the environmental temperature and moisture conditions, which will have a negative effect on its service life. Composite specimens with interlayer interfaces of double-block ballastless track were fabricated and deteriorated by an accelerated method, i.e., immersed in saturated ammonium chloride solution with various temperatures for different times. Then, the deterioration condition and mechanical properties of the composite specimens were investigated experimentally by a universal material testing machine and acoustic emission technique. The automatic sensor test (AST) method is capable of assessing the deterioration condition of the interlayer interface based on the relative wave velocity. The deterioration depth of the interlayer interface tends to increase with increasing solution temperature and immersion time. Both the solution temperature and immersion time have a negative impact on the splitting tensile strength and direct shear strength. A linear relation is found between the splitting tensile strength (direct shear strength) and the cumulative AE energy released at the fracture moment. The damage factor defined by the cumulative AE energy for most composite specimens is no greater than 0.2 before they are going to be fractured but increases sharply to 1.0 at the fracture moment.

Machine Learning Methods Based on Limited Meteorological Data to Simulate Potential Evapotranspiration: A Case Study of Source Region of Yellow River Basin

ABSTRACTSimulation of potential evapotranspiration (PET) is an important part of drought warning and water resource planning. However, the commonly used empirical models need to input a large number of meteorological elements. Therefore, to improve the efficiency and accuracy of PET simulation in areas lacking meteorological data, this study evaluated the performance of Extreme learning machine (ELM), multi‐layer perceptron (MLP), and Random Forest (RF) three machine learning methods to simulate daily PET using limited meteorological data in the source region of the Yellow River (SYRB). Two bionic optimization algorithms, Grey Wolf Optimizer (GWO) and Sparrow Search Algorithm (SSA), were used to optimise the hyperparameters of the model to improve the accuracy of the model. In addition, the effect of months on daily PET simulations was evaluated. The results showed that the daily maximum temperature (Tmax) was the most important factor affecting the PET simulation, and the daily average relative humidity (RH) and wind speed (U10) were the secondary factors. It is recommended to use Tmax, RH, U10, and sunshine duration as the optimum combination of input (R2 &gt; 0.95). In the case of limited meteorological data, the input combination of Tmax, RH, U10, or Tmax, RH (R2 &gt; 0.75) was considered. Considering the accuracy and the time and space overhead of the model, the ELM‐GWO model is recommended. When month information was used as an input factor, model performance improved in all scenarios, and June to July was the most accurate month for the model to simulate daily PET. This research resultwill allow researchers to choose the appropriate meteorological factor when simulating the PET to provide the reference.

Development of Remote-Controlled Self-Propelled Flax Windrow Turner

The paper highlights efforts by major global engineering companies to develop agricultural robotic systems, with a particular focus on universal unmanned mobile energy vehicles designed to perform technological operations autonomously. Analysis of current machinery for harvesting and preparing flax straw indicates a lack of sufficient automation and robotization in these processes. Among the operations involved in flax harvesting, turning is defined as the least energy-intensive. In this regard, research has begun on the development of a remotely controlled, self-propelled flax windrow turner, with potential for further adaptation to autonomous operation. (Research purpose) The study aims to substantiate the optimal operating modes and develop a power electrical circuit for a remotely controlled, self-propelled flax windrow turner equipped with an electric drive. (Materials and methods) The study provides a theoretical basis for the conveyor's linear speed in relation to the rectilinear motion of the flax turner. (Results and discussions) The study identified the following operating modes for the flax windrow turner: the conveyor's angular velocity was determined to be 4.63 radians per second, with a machine speed of 2.78 meters per second. Considering the machine's weight, 7.00-12 F-42-1 drive wheels were selected, with tires that offer excellent road traction and maneuverability. The drive wheels had a load index of 133, an outer diameter of 660 millimeters, and a profile width of no more than 195 millimeters without load. Additionally, a power electrical circuit was designed for a remotely controlled self-propelled flax windrow turner. (Conclusions) The study determined the operating modes for an electrified radio-controlled, self-propelled flax windrow turner and proposed a powered electrical circuit for designing the units and assemblies of machinery used in flax straw harvesting.

Optimization-Assisted Filter for Flow Angle Estimation of SUAV Without Adequate Measurement

The accurate estimation of flow angles is crucial for enhancing flight performance and aircraft safety. Flow angles of fixed-wing small unmanned aerial vehicles (SUAVs) are more vulnerable due to their low airspeed. Current flow angle measurement devices have not been widely implemented in SUAVs due to their substantial cost and size constraints. Moreover, there are no general estimation methods suitable for SUAVs based on their rudimentary sensor suite. This study presents a generalized optimization-assisted filter estimation (OAFE) method for estimating the relative velocity and flow angles of fixed-wing SUAVs based on a standard sensor suite. This OAFE method mainly consists of a cubature Kalman filter and an optimizer. The filter serves as the main loop with which to generate flow angles in real time by fusing the acceleration, angular rate, attitude, and airspeed. Without flow angle measurements, the optimizer generates approximate aerodynamic derivatives, which serve as pseudo-measurements with which to refine the performance of the filter. The results demonstrate that the estimated angle of attack and side slip angle displayed root mean square errors of around 0.11° and 0.24° in the simulation. The feasibility was also verified in field tests. The OAFE method does not require flow angle measurements, the prior acquisition of aerodynamic parameters, or model training, making it suitable for quick deployment on different SUAVs.

A Planck scale theory of time, with a fast early cosmological time rate, and rederivations for relativistic energy and time dilation

Among the issues to be resolved between general relativity and quantum mechanics are their differences about time. Block time has been weakened in two areas of its foundations recently: The small-scale reversibility has been falsified by experiments in quantum processes, and spacetime is now widely seen as emerging from unknown physics, rather than fundamental. This leaves room for differences to the nature of time. Here a theory of time is set out, in which light and matter arise in the small-scale structure of space, as waves in the dimensions themselves, traveling on the axes. It reinterprets special relativity, with two rederivations. The reasoning that led to block time, such as Penrose's version with three objects in one frame, is removed via a difference to frames that usually has no effect—the two observers are related to the event separately, as their relationships to it imply different, incompatible, positionings for the axes. This also leads to an explanation for light always moving at the same speed in relation to matter: With several objects moving differently, each is related to the light beam separately. In cosmology, new data suggest galaxies formed earlier than expected, with higher masses. And even earlier, inflation and variable speed of light theories both describe extremely rapid events. Planck scale time (PST) theory includes a specific mechanism for an overall time rate, which starts fast, then slows over time, and is consistent with supernova and gamma ray burst data. This allows galaxies more time to form, and in PST all matter's mass‐energy descends with the time rate (proportional time and energy changes in a gravitational field can be taken in the same way). This can also explain the “downsizing” sequence in galaxy formation, first described in 1996, in which stars in more massive galaxies formed earlier and quicker.

Research on the Optimal Control of Working Oil Pressure of DCT Clutch Based on Linear Quadratics Form

The control of the vehicle transmission system is of great significance to driving comfort. In order to design a controller for smooth shifting and comfortable driving, a dynamic model of dual-clutch transmission is established in this paper. An optimal control strategy for clutch oil pressure based on linear quadratics is proposed, which is used to optimally control the oil pressure of two clutches in the torque stage and inertia stage. The control strategy selects the slipping work and jerk as evaluation indices of shift quality and establishes an optimization objective function. On the premise of optimizing the input torque, the relative speed difference between the engine and the sliding clutch in the inertia stage is adjusted. Through the optimal trajectory control of the wet clutch oil pressure, slipping work and jerk are reduced, thereby improving driving comfort. The simulation results show that the slipping work and jerk generated by the system during the shift stage are reduced, and the shift quality is improved. Additionally, compared with the controller using the MATLAB particle swarm optimization algorithm, the response speed of the proposed controller is faster, the slipping work and jerk are better reduced, and the shift quality is improved.

DUVET: sub-kiloparsec resolved star formation driven outflows in a sample of local starbursting disc galaxies

ABSTRACT We measure resolved (kiloparsec-scale) outflow properties in a sample of 10 starburst galaxies from the Deep near-UV observations of Entrained gas in Turbulent (DUVET) galaxies sample, using Keck/KCWI observations of H $\beta$ and [O iii] $\lambda$5007. We measure $\sim 460$ lines of sight that contain outflows, and use these to study scaling relationships of outflow velocity ($v_{\rm out}$), mass-loading factor ($\eta$; mass outflow rate per star formation rate) and mass flux ($\dot{\Sigma }_{\rm out}$; mass outflow rate per area) with co-located star formation rate surface density ($\Sigma _{\rm SFR}$) and stellar mass surface density ($\Sigma _{\ast }$). We find strong, positive correlations of $\dot{\Sigma }_{\rm out} \propto \Sigma _{\rm SFR}^{1.2}$ and $\dot{\Sigma }_{\rm out} \propto \Sigma _{\ast }^{1.5}$. We also find shallow correlations between $v_{\rm out}$ and both $\Sigma _{\rm SFR}$ and $\Sigma _{\ast }$. Our resolved observations do not suggest a threshold in outflows with $\Sigma _{\rm SFR}$, but rather we find that the local specific star formation rate ($\Sigma _{\rm SFR}/\Sigma _\ast$) is a better predictor of where outflows are detected. We find that outflows are very common above $\Sigma _{\rm SFR}/\Sigma _\ast \gtrsim 0.1$ Gyr$^{-1}$ and rare below this value. We argue that our results are consistent with a picture in which outflows are driven by supernovae, and require more significant injected energy in higher mass surface density environments to overcome local gravity. The correlations we present here provide a statistically robust, direct comparison for simulations and higher redshift results from JWST.

In situ torque transmissibility frequency response function measurements of a centrifugal pendulum vibration absorber in a torque converter clutch damper

This investigation details torsional testing and characterization of torque converter clutch (TCC) damper variants containing centrifugal pendulum absorbers (CPAs) utilized in light duty production vehicles. Data collected on a torque converter dynamometer test stand was used to correlate a nonlinear model of the combination TCC damper and CPA when locked with zero relative slip speed. The range of test torques and speeds are related to when driveline, chassis and body noise and vibration concerns are high and the damper-CPA combination are required to provide maximum isolation. To facilitate model correlation efforts, modified configurations of the same torque converter design were procured, enabling separation of damping effects from the CPA and damper springs. Under load, the locked TCC was torsionally excited to acquire torque transmissibility frequency response functions (TTFRFs). The anti-resonance of the CPA was measured, and the viscous damping coefficient estimated. A manual tuning and modified half-power bandwidth method were used to estimate the equivalent viscous damping of the CPA. Additional test cases included torsional excitation amplitude and oil temperature to ascertain differences in CPA response and tuning order. The objective of the investigation is to demonstrate the influence of damper spring and CPA integration, extraction of CPA damping from actual hardware and the utility of including representative damping in model-based design of future damper-CPA assemblies.