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One often-overlooked consequence of stroke is a deficit in emotion regulation. Acting with awareness in everyday life has been found to support emotion regulation but it is an open question whether such associations generalize to stroke populations. Factors associated with emotion regulation in stroke survivors are key to inform rehabilitation efforts. This study used up to 14 repeated daily life assessments to examine everyday associations between acting with awareness and affect in a sample of 86 community-dwelling adults post-stroke living in Southern British Columbia, Canada (M age  = 68.70, SD = 10.56; range = 33-88; 26.7% female; 63.8% with less than college degree). Multilevel models examined the extent to which daily acting with awareness, previous-day negative affect, and previous-day positive affect were associated with daily negative and positive affect. Multilevel models operationally defined emotion regulation as affect carry-over, the extent to which affect lingered from one day to the next. Results revealed that on days when acting with awareness was elevated, negative affect did not carry over from the previous day, suggesting greater emotion regulation. Additionally, on days when acting with awareness was elevated, positive affect was maintained from day to day, indicating lingering positivity effects. Future research should expand upon our correlational findings, as the opposite causal direction might also hold-affect may increase the likelihood of acting with awareness. Overall, findings suggest that mindfulness-based interventions after stroke might benefit from a greater focus on daily acting with awareness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

An ambient modal framework for inertia estimation using synchrophasor data is proposed in this letter. Specifically, an analytical formulation is developed for the estimation of inertia based on the frequency and damping ratio modes extracted from ambient data. An advantage of the proposed framework is that it can rely on synchronized ambient data under non-disturbed conditions for online estimation and tracking of inertia. Ultimately, numerical simulation studies and physical experiments demonstrate the feasibility of the proposed approach.

Compared to conventional DC transmission, Voltage source converter based high voltage direct current transmission (VSC-HVDC) has the advantages of independently controllable transmission power, no commutation failure, no reactive power compensation and low harmonic levels. However, VSC-HVDC transmission cannot provide effective frequency support and regulation for the system after grid connection. For this reason, an adaptive neural fuzzy virtual inertia control method is proposed to impose a control strategy on the converter at the receiving end of a VSC-HVDC transmission. The method uses the frequency change rate and the amount of change of frequency as constraints to dynamically adjust the virtual inertia and damping coefficients. It provides larger inertial support when the frequency fluctuation is large and smaller inertial support when the frequency fluctuation is small, thus adapting to different operating conditions. Finally, a hardware-in-the-loop simulation platform is built. The superiority and application prospect of the proposed strategy in frequency stability of the system are verified by comparing the proposed strategy with the traditional virtual control strategy.

Bluetongue (BT) is a non-contagious virus in the Reoviridae family that infects both wild and domestic animals. It causes economic losses and reduces infected animals' production and reproduction. A total of 233 apparently healthy animals were screened for BT. Profiles of health condition of animals were identified using multiple correspondence analysis (MCA) and hierarchical cluster analysis (HCA), and the impact of the change in disease condition of animals was explored by examining the subjective evaluation of the impact of risk factors like (age, sex, season, species, and locality) with regard to BT disease providing an insight into a dataset through information visualization and it presents a useful application for visualizing associations amongst variable categories. The first two MCA dimensions retained up to 27% of the total inertia contained in the data. The positive BT results, summer, and old animals categories were loaded in the first dimension, while negative cases, Al-mounfia and winter categories were related to the second dimension. HCA identified three clusters. Cluster 1 was characterized by frequent and largely exclusive seronegative BT animals 91.67 % of animals in the cluster were seronegative, negative BTV category is the most important and related to cluster 1 with positive v-test=8.75. Cluster 3 can named a cluster of seropositive BT, up to 88% of cases were seropositive. We can conclude that seropositive BT is associated with summer and old age categories, whereas seronegative BT is associated with young age and winter categories, and thus MCA and HCA provide convenient and easy-to-interpret analytical tools for assessing categorical data relationships.

Urban ropeways are a novel option to extend public transport. Technically suited to a range of use cases, urban ropeways have not yet been implemented as part of a public transport solution in Germany. Rather than the technology itself, specific routines and practices of the public transport service regime have been identified as main challenges. Building on series of expert workshops conducted in 2017 (23 participants in total), we look beyond technical characteristics and study the preparedness of service regime actors regarding processes and routines as well as structural factors of inertia. Generally, we observe an increasing openness towards reflecting about integrating urban ropeways into public transport. However, misalignment is still clearly visible: First, lacking experiences with this new option at the local level imply a time-consuming need for information and clarification. Second, and more fundamentally, the suitability of established planning routines is questioned, which is critical because the dense regulatory framework existing in Germany currently requires these. We discuss the implications at the level of the service regime and the relevance of these structural mechanisms in considering technological potentials in a mobility transition more generally.

Background: The prevalence of diabetes mellitus is growing worldwide, showing almost a 10-fold increase in the last five decades. Despite advances in the understanding of the disease mechanisms, preventive measures, and treatment options, morbidity and mortality remain high. Moreover, the burden of uncontrolled glycemia and associated complications have a significant impact on healthcare costs. To be ready for the future and emerging issues in the management of diabetes and related disorders, a holistic approach is essential for the prevention of the next generations. So many challenges in the management of diabetes exist globally, which differ according to the health infrastructure, and cultural, economic, and sociodemographic status of the nations. Conclusions: In this minireview and commentary on previously unaddressed needs relating to the management of diabetes, we discuss the ubiquitous and most compelling challenges and suggest potential solutions in the care of patients with diabetes.

In studies of dynamic stability and power quality, it is necessary to know the values of the mechanical parameters determining the transient response of wind turbines. Their exact values are not as decisive as the power curve, but an inaccurate estimate can distort or even invalidate the simulation results. From a review of the literature, it has been found that, despite their importance, the values of inertia, stiffness and damping are hardly available for any turbine model. Another detected problem is the lack of confidence in the data origin. This article aims to solve the issue of the scarcity and unreliability of data on inertia, and gathers the information found on the remaining mechanical parameters. Available blade inertia values in kg · m2 are presented. Special treatment has been given to those providing the mass distribution along the blade span, for which the provided values of inertia have been compared with those obtained numerically, showing good matching. With this, different reliable relations are obtained that allow for the calculation of the turbine rotor inertia, based on the mass and length of the blade. When the center of gravity is also available, a very correlated expression (r2=0.975) is provided to obtain the inertia. The references to the stiffness and damping constant of the drive train, which are even more rare, will also be presented. In addition, the study includes a revision of gearboxes, generators and blade weight, according to their IEC-class and material.

Purpose: Knowledge inertia is the tendency to rely on past procedures, knowledge, or experience to address new issues and problems. In other words, it considers the future as today. In fact, individuals and organizations rely on their previous knowledge and experience to navigate unprecedented and new conditions. Therefore, the present study was conducted to analyze the consequences of knowledge inertia in knowledge-based companies. Method: The current research utilizes a mixed methods approach, incorporating both qualitative and quantitative methods within the inductive-deductive paradigm. It is also practical in terms of its purpose and exploratory in terms of its nature and method. It is important to note that the statistical population for both the qualitative and quantitative parts of the research consists of experts, including managers of knowledge-based companies in Lorestan province and professors from the management department of Lorestan University. A purposeful sampling method was used to select 14 individuals as sample members. Therefore, according to the principle of theoretical sufficiency (which occurs when the researcher has gathered all available data and information necessary to understand the phenomenon and gain knowledge), the necessary data were collected to the fullest extent. It should be noted that in the qualitative aspect of the thematic analysis approach, apart from reviewing articles, books, and magazines, semi-structured interviews were also conducted. The validity and reliability of these interviews were assessed using the CVR coefficient and the Kappa-Cohen test, respectively. Confirmed. In the quantitative section, the data collection tool is the Delphi questionnaire. Its validity and reliability were confirmed using content validity and inconsistency rate, respectively. Findings: The current research utilizes a mixed approach (qualitative and quantitative). The results obtained in the qualitative part indicate the identification of the consequences of knowledge inertia in knowledge-based companies. The results of this section, following data analysis using the coding approach (open, central, and selective coding) and Atlas.ti software, reveal fifteen factors as consequences of knowledge inertia in knowledge-seeking companies. In the quantitative aspect of the research, the fuzzy Delphi method was employed to prioritize the consequences of knowledge inertia in scientific companies. The results indicate that the disclosure of the organization's strategies, the enhancement of predictability in the organization's operations, and the increase in stagnation and intellectual inertia are significant outcomes. The most significant consequences of knowledge inertia in knowledge-based companies are the loss of creativity and innovation, resistance to change, reduced performance, diminished organizational learning, and decreased agility and flexibility. Conclusion: Knowledge is considered one of the most fundamental and crucial assets for competing in the new millennium. No matter how many resources an organization has, if it does not leverage modern knowledge and science, its resources will remain stagnant and it will be practically unable to use them optimally. Acquiring knowledge and leveraging it can enhance the organization's growth and excellence, ultimately improving its competitive position. In other words, knowledge determines the efficient and effective utilization of other resources for the organization. In this way, the dominance of knowledge inertia causes the organization to cease acquiring new knowledge and learning, and instead rely on outdated versions and strategies to solve its issues and challenges. In other words, stagnation and intellectual inertia within the organization are increasing day by day. It should be noted that the organization is losing the ability to generate new and original ideas, as well as other methods and techniques to address recurring threats and ultimately predict competitors' actions. On the other hand, knowledge inertia poses a challenge by hindering the organization's ability to respond quickly, effectively, and efficiently to the opportunities created in the environment. This distortion affects the organization's agility and speed of action.

The growing share of generation from wind farms is becoming one of the challenges in maintaining the sustainability of electric power systems. System operators approve requirements for the participation of such plants in frequency and power regulation, but they do not contain requirements for specific technologies in the control of wind turbines. There are several methods of frequency and power control, which are implemented by additional control systems, the implementation of underload mode, extraction of hidden inertia, the use of energy storage devices, etc. Each of these methods has both advantages and disadvantages. In this paper we consider the combined coordinated control of type 3 wind turbines using kinetic energy and energy from hydrogen storage to provide the best frequency response in order to minimize the negative factors. A digital-analog-physical model of type 3 wind turbine is used as a model, which allows to reproduce the whole range of transients most accurately and avoid the limitations of strictly numerical simulation. [ABSTRACT FROM AUTHOR]

This paper investigates the importance of bureaucratic inertia in foreign aid allocation. Inertia puts a limit on the ability of foreign aid to alleviate poverty and promote growth. We exploit the 9/11 attacks as a natural experiment that provides a lower bound on the effects of inertia. We make use of a dynamic panel data model combined to a proper treatment of the sample selection problem inherent to virtually all models on aid decisions. The paper moves beyond existing studies and provides an ordering of the donor's motivations. Interestingly, merit-based motivations have sizable effects on aid decisions. However, inertia is found to drive most of the aid distribution. This may provide a rationale for the weak enforcement of aid contracts. Inertia introduces a time inconsistency problem on the side of the donor. Ex-post, the donor of conditional aid has incentives to deliver it regardless of reforms' implementation or recipient's discipline. Anticipation that this will happen destroys the recipient's incentive to carry out costly policy reforms. This puts the whole aid architecture under strain. Coordination among donor agencies, donors' investment in reputation and institution building as well as changing aid modalities rather than volumes seems to be promising routes toward re-establishing efficiency. [ABSTRACT FROM AUTHOR]

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For positive real numbers r, p0, and p1 < ··· < pn; let Kr be the n × n Kraus matrix whose (i; j) entry is equal to ... [ABSTRACT FROM AUTHOR]

The modern power system is experiencing transformation from the rotational-generation-equipment-dominated system to a power-electronics-converter-dominated system, with the increasing penetration of renewable energy resources such as wind and photovoltaic. The power-electronics-based renewable generation, as well as energy storage system, can lead to the reduction of system inertia. As dc systems such as dc microgrids are attracting more attention, the low-inertia issues will challenge their stability. In this paper, a comprehensive review of inertia-enhancement methods in dc power systems is presented. The concept and significance of the inertia in dc systems is firstly introduced, and then the types of inertia-providing sources in dc systems are discussed. After that, the different virtual inertia control strategies applied in power electronics converters are classified and investigated. These virtual inertia control methods are proven to have a great ability to enhance the inertia of a dc system. The challenges and future research direction are discussed at the end of the article. In this paper, the previous research work on the inertia of dc power systems is summarized in detail, the inertia-enhancement methods of DC systems are comprehensively introduced, and the future research directions are prospected. [ABSTRACT FROM AUTHOR]

A general linear random-effects model y = X β + ε with β = Z α + γ that includes both fixed and random effects and its two transformed models A : Ay = AXZ α + AX γ + A ε and B : By = BXZ α + BX γ + B ε are considered without making any restrictions on correlation of random effects and any full rank assumptions. Predictors of joint unknown parameter vectors under the transformed models A and B have different algebraic expressions and different properties in the contexts of the two transformed models. In this situation, establishing results on relations and making comparisons in between predictors under the two models are the main focuses. We first investigate relationships of best linear unbiased predictors (BLUPs) of general linear functions of fixed and random effects under the models A and B and construct several equalities for the BLUPs. Then, the comparison problem of covariance matrices of BLUPs under the models is considered. We derive from matrix rank and inertia formulas the necessary and sufficient conditions for variety of equalities and inequalities of covariance matrices' comparisons under the models A and B. [ABSTRACT FROM AUTHOR]

Experience is the best teacher. Yet, in the context of repeated decisions, experience was found to trigger deviations from maximization in the direction of underweighting of rare events. Evaluations of alternative explanations for this bias led to contradicting conclusions. Studies that focused on the aggregate choice rates, including a series of choice prediction competitions, favored the assumption that this bias reflects reliance on small samples. In contrast, studies that focused on individual decisions suggest that the bias reflects a strong myopic tendency by a significant minority of participants. The current analysis clarifies the apparent inconsistency by reanalyzing a data set that previously led to contradicting conclusions. Our analysis suggests that the apparent inconsistency reflects the differing focus of the cognitive models. Specifically, se- quential adjustment models (that assume sensitivity to the payoffs' weighted averages) tend to find support for the hypothesis that the deviations from maximization are a product of strong positive recency (a form of myopia). Conversely, models assuming random sampling of past experiences tend to find support to the hypothesis that the deviations reflect reliance on small samples. We propose that the debate should be re- solved by using the assumptions that provide better predictions. Applying this solution to the data set we analyzed shows that the random sampling assumption outperforms the weighted average assumption both when predicting the aggregate choice rates and when predicting the individual decisions. [ABSTRACT FROM AUTHOR]

This paper considers comparison problems of predictor and estimator in the context of seemingly unrelated regression models (SURM s). SURM s are a class of multiple regression equations with correlated errors among the equations from linear regression models. Our aim is to establish a variety of equalities and inequalities for comparing covariance matrices of the best linear unbiased predictors (BLUP s) and the ordinary least squares predictors (OLSP s) of unknown vectors under SURM s by using various rank and inertia formulas of block matrices. The results for comparisons of the best linear unbiased estimators (BLUE s) and the ordinary least squares estimators (OLSE s) in the models are also considered. [ABSTRACT FROM AUTHOR]

Seed dispersal by wind is one of the most important dispersal mechanisms in plants. The key seed trait affecting seed dispersal by wind is the effective terminal velocity (hereafter "terminal velocity", Vt), the maximum falling speed of a seed in still air. Accurate estimates of Vt are crucial for predicting intra‐ and interspecific variation in seed dispersal ability. However, existing methods produce biased estimates of Vt for slow‐ or fast‐falling seeds, fragile seeds, and seeds with complex falling trajectories. We present a new video‐based method that estimates the falling trajectory and Vt of wind‐dispersed seeds. The design involves a mirror that enables a camera to simultaneously record a falling seed from two perspectives. Automated image analysis then determines three‐dimensional seed trajectories at high temporal resolution. To these trajectories, we fit a physical model of free fall with air resistance to estimate Vt. We validated this method by comparing the estimated Vt of spheres of different diameters and materials to theoretical expectations and by comparing the estimated Vt of seeds to measurements in a vertical wind tunnel. Vt estimates closely match theoretical expectations for spheres and vertical wind tunnel measurements for seeds. However, our Vt estimates for fast‐falling seeds are markedly higher than those in an existing trait database. This discrepancy seems to arise because previous estimates inadequately accounted for seed acceleration. The presented method yields accurate, efficient, and affordable estimates of the three‐dimensional falling trajectory and terminal velocity for a wide range of seed types. The method should thus advance the understanding and prediction of wind‐driven seed dispersal. [ABSTRACT FROM AUTHOR]

In this paper, we consider a comparison problem of predictors in the context of linear mixed models. In particular, we assume a set of m different seemingly unrelated linear mixed models (SULMMs) allowing correlations among random vectors across the models. Our aim is to establish a variety of equalities and inequalities for comparing covariance matrices of the best linear unbiased predictors (BLUPs) of joint unknown vectors under SULMMs and their combined model. We use the matrix rank and inertia method for establishing equalities and inequalities. We also give an extensive approach for seemingly unrelated regression models (SURMs) by applying the results obtained for SULMMs to SURMs. [ABSTRACT FROM AUTHOR]

We provide eigenvalues bounds for a new formulation of the step equations in interior methods for convex quadratic optimization. The matrix of our formulation, named K 2.5 , has bounded condition number, converges to a well-defined limit under strict complementarity, and has the same size as the traditional, ill-conditioned, saddle-point formulation. We evaluate the performance in the context of a Matlab object-oriented implementation of PDCO, an interior-point solver for minimizing a smooth convex function subject to linear constraints. The main benefit of our implementation, named PDCOO, is to separate the logic of the interior-point method from the formulation of the system used to compute a step at each iteration and the method used to solve the system. Thus, PDCOO allows easy addition of a new system formulation and/or solution method for experimentation. Our numerical experiments indicate that the K 2.5 formulation has the same storage requirements as the traditional ill-conditioned saddle-point formulation, and its condition is often more favourable than the unsymmetric block 3 × 3 formulation. [ABSTRACT FROM AUTHOR]

Modern electricity networks may face inertia shortages based on increasing inverter-based renewable energy penetration, along with the (often concurrent) decommissioning of aging synchronous thermal generators. In the South African network, the market share of coal generation is projected to decrease significantly based on the country's energy policy, primarily to be replaced by wind and solar PV. In this paper the inertia adequacy on the future South African network is evaluated, and the viability of converting retired synchronous generators to synchronous condensers is assessed based on sufficiency of inertia support provided and economic viability. It is found that by 2030, the South African network will have insufficient inertia for a significant portion of the year. However, significant improvements in Rate of Change of Frequency and frequency nadir are observed when incorporating inertia from converted synchronous condensers during multiple-contingency trip events. Finally, the conversion of synchronous generators to synchronous condensers is found to be the least-cost solution when compared to the installation of new synchronous condensers or of large-scale battery systems. The contributions made in this paper highlight the importance of considering network inertia in establishing a national energy policy, while also informing solutions to future inertia constraints. • The future South African electricity network will face significant inertial shortages by 2030. • Converting retired synchronous generators to synchronous condensers will significantly reduce inertia shortages. • The conversion of retired synchronous generators to synchronous condensers is cost-effective as an inertia support mechanism [ABSTRACT FROM AUTHOR]

The large and sustained yield gains achieved since the introduction of maize hybrids in the 1930s (about 1.8 bushels per acre per year) have been accompanied by a remarkably parallel and steady increase in seeding density. This increase occurred in an environment characterized by rapid technological innovation, including genetic engineering, and commercial hybrid varieties with short life cycles. An important question, then, is whether and how breeders and farmers have learned about the optimal planting density. In this paper, we use unique and detailed U.S. farm‐level data, consisting of more than 400,000 planting choices from 1995–2016, to assess the nature of learning about seeding density. Importantly, we control for unobserved confounders through both hybrid and farm‐level fixed effects. We find that the variance in planting rates for a given hybrid has decreased over time, and that farmers tend to plant a given variety at higher rates over time. This is consistent with Bayesian learning in which risk‐neutral farmers possess priors consistently below the true optimal rate. We cast doubt on risk aversion as a credible explanation for this finding by analyzing the contrasting evolution of soybean planting rates (a crop with exogenously different agronomic determinants of seed density). We interpret our results as evidence of inertia: the initial bias in maize farmers' priors is tilted towards the optimal planting rates of varieties planted in the past. One implication of the finding that farmers historically underinvested in seeding rates is that eliminating this tendency could result in productivity gains. [ABSTRACT FROM AUTHOR]

In this article, we analyze the phase synchronization and frequency synchronization for the bidirectionally coupled Kuramoto model under the effect of inertia. Unlike the classical Kuramoto model equipped with all-to-all coupled interaction, in the setting of this model, each oscillator θ i only interacts directly with θ i + 1 and θ i − 1. The bidirectional interaction is a typical setting of the concatenation in power systems. Additionally, it is necessary to impose the effect of inertia in the Kuramoto model in the applications such as power systems and Josephson junction array. In this article, we first present a theory of the global convergence for frequency synchronization for the identical case. For the non-identical case, we prove that the second-order bidirectionally coupled Kuramoto model exhibits a frequency synchronization if the coupling strength is large, inertia is small, and all oscillators are initially confined to a sector. We emphasize that the arc length of this sector possesses a positive lower bound which is independent of the number of oscillators. If, in addition, all natural frequencies are identical, we further show that the phase synchronization emerges. Moreover, we demonstrate the numerical simulations to support the main results. On the other hand, we observe that the model equipped with large inertia can exhibit the synchronization. Exploring the synchronization theory for large inertia case is left as the future work. [ABSTRACT FROM AUTHOR]

BackgroundThe current management of patients with Dementia, primarily with Alzheimer's Disease (AD) is rapidly evolving. However, limited information is available about the current gaps and decision-making in primary care.ObjectivesTo evaluate factors associated with gaps, risk preferences regarding diagnostic and therapeutic choices in the management of patients with AD by primary care physicians (PCP) from across Canada.MethodsWe propose a non-interventional, cross-sectional pilot study involving 120 primary care physicians referred from the College of Family Physicians of Canada to assess diagnostic and therapeutic decisions in the management of ten simulated AD-related case-scenarios commonly encountered in clinical practice. We initially describe the current landscape and gaps regarding diagnostic and therapeutic challenges in the management of patients with AD in primary care. Then, we provide concepts from behavioral economics and neuroeconomics applied to medical decision-making. Specifically, we include standardized tests to measure risk aversion, physicians' reactions to uncertainty, and questions related to risk preferences in different domains. Finally, we summarize the protocol to be implemented to address our goals. The primary study outcome is the proportion of participants that elect to defer initial investigations to the specialist and the associated factors. Secondary outcomes include the proportion of PCP willing to order cerebral spinal fluid studies, PET scans, or initiate treatment according to the simulated case-scenarios. The study will be conducted in English and French.ConclusionsThe study findings will contribute a better understanding of relevant factors associated with diagnostic and therapeutic decisions of PCP in the management of AD, identifying participant's preferences and evaluating the role of behavioral aspects such tolerance to uncertainty, aversion to ambiguity, and therapeutic inertia.

Large-scale photovoltaic (PV) generation grid connection causes lack of inertia and insufficient frequency regulation capacity of power system. To solve this problem, this study proposed the active power-frequency droop control (APFDC) and virtual inertia control (VIC) for single-stage PV generation. PV generation is able to participate in the grid frequency regulation by improving the control system of voltage source converter (VSC). The effect of control parameters on the inertia characteristic of PV generation is analyzed. On this basis, the distribution mechanism of unbalanced active power among PV generators with inertia control strategy is revealed. The simulation results indicated that PV generation can be controlled by setting the control strategy of the voltage source converter (VSC) to reduce or increase the active power; it also takes part in the frequency regulation of the system. The inertia provided by PV generation is controllable and frequency-dependent, increases with the increase in control gain, the decrease in the time constant of VIC, and the decrease in phase-locked loop (PLL) control bandwidth.

Abstract Seed dispersal by wind is one of the most important dispersal mechanisms in plants. The key seed trait affecting seed dispersal by wind is the effective terminal velocity (hereafter “terminal velocity”, Vt), the maximum falling speed of a seed in still air. Accurate estimates of Vt are crucial for predicting intra‐ and interspecific variation in seed dispersal ability. However, existing methods produce biased estimates of Vt for slow‐ or fast‐falling seeds, fragile seeds, and seeds with complex falling trajectories. We present a new video‐based method that estimates the falling trajectory and Vt of wind‐dispersed seeds. The design involves a mirror that enables a camera to simultaneously record a falling seed from two perspectives. Automated image analysis then determines three‐dimensional seed trajectories at high temporal resolution. To these trajectories, we fit a physical model of free fall with air resistance to estimate Vt. We validated this method by comparing the estimated Vt of spheres of different diameters and materials to theoretical expectations and by comparing the estimated Vt of seeds to measurements in a vertical wind tunnel. Vt estimates closely match theoretical expectations for spheres and vertical wind tunnel measurements for seeds. However, our Vt estimates for fast‐falling seeds are markedly higher than those in an existing trait database. This discrepancy seems to arise because previous estimates inadequately accounted for seed acceleration. The presented method yields accurate, efficient, and affordable estimates of the three‐dimensional falling trajectory and terminal velocity for a wide range of seed types. The method should thus advance the understanding and prediction of wind‐driven seed dispersal.

Energy of a molecule plays an important role in physics, chemistry and biology. In mathematics, the concept of energy is used in graph theory to help other subjects such as chemistry and physics. In graph theory, nullity is the number of zeros extracted from the characteristic polynomials obtained from the adjacency matrix, and inertia represents the positive and negative eigenvalues of the adjacency matrix. Energy is the sum of the absolute eigenvalues of its adjacency matrix. In this study, the inertia, nullity and signature of the aforementioned structures have been discussed.

In a constantly and rapidly changing global environment, one of the main priority tasks for every country is preserving, maintaining, and operating an independent and individually robust and stable energy system. This paper aims at researching electrical power systems’ (EPSs) behavior during desynchronization from a synchronous area, its stability in islanded mode, and its synchronization. The analysis of EPS behavior was accomplished utilizing numerical simulations in a widely used programming/simulation package. The sudden tripping of the EPS into an isolated island mode with known generation and load values was simulated, analyzed, and discussed. We investigated the behavior of an isolated EPS in the case of the loss of a certain amount of active power, and determined the maximum power that must be available to ensure the reliable operation of the isolated EPS and the power reserve that must be maintained to prevent the EPS from triggering UFLS. The simulation of the synchronization of an isolated EPS with a synchronous area was accomplished and analyzed. The obtained results were applied to reveal the sequence of actions that will help an EPS to ensure and maintain the stable and reliable operation of electrical installations during desynchronization.

A mathematical model is developed to investigate the combined effect of fluid cavitation and inertia on the fluid pressure buildup of parallel textured surfaces. The fluid cavitation is analyzed using the Rayleigh–Plesset model, and the fluid inertia is analyzed with an averaged method. The finite element method and Newton-downhill method are employed to solve the governing equations. The numerical model is validated by comparing the experimental and numerical results, and the combined effect of fluid cavitation and inertia on the fluid pressure buildup is analyzed and discussed. The research indicates that the cavitation weakens the fluid inertia effect on the pressure distribution at the inlet area of textures. The fluid inertia greatly enhances the hydrodynamic effect and effectively limits the excessive extension of the low-pressure zone caused by cavitation. The fluid cavitation and inertia, especially their interaction, significantly affect the fluid pressure buildup and generate a net load-carrying capacity (LCC). The numerical model with the fluid inertia and cavitation is more time saving than the commercial CFD tools in solutions, which gives a novel and optional HD foundation for developing a more efficient and accurate THD or TEHD model by numerical programming.

Humans exhibit unique skeletal muscle morphologies that are known to matter in upright bipedalism. However, their relevance to the ease of leg swing, which limits locomotion performance, remains unclear. Here, we aimed to examine muscle mass distribution within the human leg and the effect of each muscle on the ease of leg swing. We calculated the mass, center of mass position, and moment of inertia around the hip extension-flexion axis for all leg muscles by using a publicly available dataset of the 3D reconstruction of the musculoskeletal components in human male and female legs. The leg muscles showed a top-heavy-bottom-light tapering trend; muscles far from the hip joint tended to have smaller masses. Interestingly, however, the soleus exhibited sizable mass for its location. Consequently, the moment of inertia of the soleus was exceptionally greatest, accounting for approximately one-quarter of that of all muscles. These results indicate that compared to the other muscles the soleus muscle has a much larger effect on the leg moment of inertia and uniquely makes humans difficult to swing the leg, although the leg muscles basically show the top-heavy bottom-light tapering trend favoring the leg swing. Our findings highlight a novel functional consequence of human body evolution, suggesting that muscular enlargement for postural stability and endurance capacity has compromised the locomotion speed during the adaptation to bipedalism. [ABSTRACT FROM AUTHOR]

• Used Practical Epistemology Analysis and Transactional Learning Theory in two Dutch water cases. • Three-year embedded action research yields a worm-eye view on resistance and inertia. • Insights on learning moments reveal diverse dynamics of incumbency at the micro-level. • Co-creation stalled when citizen concerns were not resolved, or commitment waned. • Incumbency resides not only with regime-actors, but also governments and citizens. Existing transitions literature often highlights successful experiments for changing practices through multi-actor processes but overlooks the challenges of adjusting incumbent practices and engaging actors in reflexive learning. The current article addresses this gap through two qualitative case studies of water-related co-creation processes in the Netherlands. Each case met inertia and resistance from various actors in different forms. We examine the difficulties encountered using data from semi-structured interviews and observations of micro-level interactions from embedded action research. We find that using transactional learning perspective combined with Practical Epistemology Analysis is useful for obtaining a worm-eye view of dynamics of incumbency on the actor-level, in contrast to the eagle-eye view commonly adopted in transitions studies. Our main contribution is the identification of specific barriers to change and demonstrating how a worm-eye perspective offers detailed insights into micro-level interactions that hinder sustainability transitions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Failure of the mass-on-spring system is discussed. • Fracture delay and strength increase for high rates are studied. • The oscillator model is calibrated to address three sets of experimental data. • Analogies between the oscillator model and the incubation time model are shown. The work considers failure of a linear oscillator (a mass-on-spring system) and the corresponding simple engineering approach to dynamic fracture of solids. The system is studied when subjected to two distinct types of load: a short pulse load and a linearly increasing load. These two cases are used to reveal two key dynamic fracture effects observed in dynamically loaded media: the fracture delay and increase of the system strength for high-rate loading. The inertia of the mass helps to capture these effects and thus to clearly show inapplicability of standard strength models when dynamic loads are considered. The linear oscillator is shown to be a basis for an easy to operate yet capable fracture model which admits "ad-hoc" application to various dynamic fracture cases. In this work the model is calibrated in order to fit known experimental results on dynamic crack initiation in plates and on spallation observed in rods. The model shows good performance despite its simplicity and strength of the made assumptions. [ABSTRACT FROM AUTHOR]

The islanded mode of operation of an electric power system (EPS) that has generation capabilities provided by conventional thermal power plants, by a pumped-storage power station, or from an interlink with a neighboring electric power system through an HVDC BtB converter is addressed in this paper. The risk for electrical power systems to fall into an islanded mode has recently grown, as it is caused not just by technical reasons but by a geopolitical situation as well. The current strains demand the close consideration of problems related to EPS operation in an islanded mode. This paper considers several. The research covers the following issues. The response of the islanded system to a sudden and spasmodic load change is analyzed in cases when the system deals with the disturbance with internal resources alone and with the help of an HVDC BtB converter's frequency control functionality. Analysis of the impact of the settings of the HVDC BtB converter on the system's response to disturbances is presented and the optimal set of parameters found. The impact of the system's extended inertia on the system's response is evaluated by using an additional unit of the pumped-storage power station in synchronous condenser mode. Transients in the system when switching a unit operating in synchronous condenser mode on and off are analyzed. The capability of the system to withstand major disturbances, such as disconnection of the pumped-storage power station's unit operating in a pump mode and disconnection of the HVDC BtB converter in emergency modes, if a situation demands, is researched. The research is carried out by numerical simulations using PSS Sincal Electricity Basic software. Updated operating parameters of the isolated power system and the LCC HVDC BtB converter, as well as frequency control automation provided by ABB, were used in the simulations. [ABSTRACT FROM AUTHOR]

The reduced inertia levels in low-carbon power grids necessitate explicit constraints to limit frequency’s nadir and rate of change during scheduling. This can result in significant curtailment of renewable energy due to the minimum generation of thermal plants that are needed to provide frequency response (FR) and inertia. Additional consideration of fast FR, a dynamically reduced largest loss and under frequency load shedding (UFLS) allows frequency security to be achieved more cost effectively. This paper derives a novel constraint from the swing equation to contain the frequency nadir using all of these services. The expected cost of UFLS is found probabilistically to facilitate its comparison to the other frequency services. We demonstrate that this constraint can be accurately and conservatively approximated for moderate UFLS levels with a second order cone (SOC), resulting in highly tractable convex problems. Case studies performed on a Great Britain 2030 system demonstrate that UFLS as an option to contain single plant outages can reduce annual operational costs by up to $\pounds $ 559 m, 52% of frequency security costs. The sensitivity of this value to wind penetration, abundance of alternative frequency services, UFLS amount and cost is explored. [ABSTRACT FROM AUTHOR]