Dependence Of Growth Rate Research Articles

Simulation of parametric decay instability excited by oscillating pump near lower hybrid frequency

Parametric decay instability of lower hybrid waves plays an important role in plasma heating. Simulation of such instability requires inclusion of both electron and ion kinetics with a realistic mass ratio. In this work, the gyrokinetic electron and fully kinetic ion (GeFi) particle simulation model is used to study parametric instabilities in uniform, magnetized plasmas. A pump electric field near the lower hybrid frequency is imposed, which is treated in the dipole approximation. Three types of parametric decay processes are obtained, including purely growing modulational instability, resonant decay instability, and non-resonant decay instability. Dependences of parametric growth rates on the wavenumber, pump strength, and pump frequency are systematically investigated. The simulation results agree well with those in the linear growth stage of parametric decay instability obtained in an existing theory. Whether electron or ion nonlinearity dominates in the parametric decay process is assessed, and the importance of the electron E×B drift in the three-wave interaction process is confirmed.

Foundation of multilevel apploach to fracture modeling for materials with submicrostructure applicable for Arctic and Subarctic environment

A short review of research on multiscale modeling of the fracture processes of heterogeneous materials with submicrostructures applicable to Arctic and Subarctic environments is presented. The results of solving a number of model problems, both in terms of macroscopic strength and main crack growth, and describing the accumulation of microscopic defects and hierarchical fracture processes by the mechanisms of formation, growth, and fusion of secondary and microcracks, and microscopic pores are provided. Thus, for the fracture process of samples of porous concrete modified with oil palm fruit fibers to improve its consumer qualities, a simulation of crack growth was conducted, which showed a decrease in the crack resistance of the material with increasing fiber content. A three-point bend test was used to evaluate the bending strength and modulus of elasticity, and the compressive strength and modulus of elasticity were determined. An increase in the fiber content led to a decrease in the compressive strength and modulus of elasticity. The fracture surface analysis revealed the mechanism of crack propagation through the coalescence of micropores. The basis of the modeling was an experimentally substantiated criterion for concentrated fractures during crack formation based on percolation theory. Macroscopic finite-element and stochastic modeling of fractures during the bending of a beam made of wood have also been carried out. For wooden structures, the peculiarity is the anisotropic behavior of the material in the loading direction. The structure of the Bilinga tree timber at the mesoscopic and microscale levels was considered, and a hierarchy of the spatial and temporal scales of the fracture process was constructed. The crack growth rates at different scales were determined and compared with macroscopic FE simulations. Another task was to determine the dependence of the crack growth rate in the soil, such as regolith, under the influence of an ultrasonic impactor. Stochastic modeling of the crack growth in the array of micropores revealed the crack growth rate dependence on the ultrasonic transmitter beater parameters and pulse amplitude.

Nutrients strengthen density dependence of per-capita growth and mortality rates in the soil bacterial community.

Density dependence in an ecological community has been observed in many macro-organismal ecosystems and is hypothesized to maintain biodiversity but is poorly understood in microbial ecosystems. Here, we analyze data from an experiment using quantitative stable isotope probing (qSIP) to estimate per-capita growth and mortality rates of bacterial populations in soils from several ecosystems along an elevation gradient which were subject to nutrient addition of either carbon alone (glucose; C) or carbon with nitrogen (glucose + ammonium-sulfate; C + N). Across all ecosystems, we found that higher population densities, quantified by the abundance of genomes per gram of soil, had lower per-capita growth rates in C + N-amended soils. Similarly, bacterial mortality rates in C + N-amended soils increased at a significantly higher rate with increasing population size than mortality rates in control and C-amended soils. In contrast to the hypothesis that density dependence would promote or maintain diversity, we observed significantly lower bacterial diversity in soils with stronger negative density-dependent growth. Here, density dependence was significantly but weakly responsive to nutrients and was not associated with higher bacterial diversity.

An investigation of the relation between life expectancy & socioeconomic variables using path analysis for Sustainable Development Goals (SDG) in Bangladesh.

In today's world, the key variable for measuring population health is life expectancy (LE). The purpose of this research is to find out how life expectancy is related to other factors and develop a model to account for the predictors that contribute to LE. This study is also conducted to investigate and measure the effect of socioeconomic variables on LE in Bangladesh. In this study, the predictor variables are employment rate, gross national income (GNI), population growth rate, unemployment rate, and age dependency ratio. Path analysis disintegrated bivariate analysis and showed that employment rate, GNI, and age dependency ratio are significantly related to life expectancy, although bivariate analysis showed all variables are significantly related to LE. The maximum values of significant factors, GNI and employment rates, are $1930 and 21.32% happened in 2019, which is positively correlated with life expectancy. Also, the maximum value of the age dependency ratio (81.52%) happened in 1991, whereas the maximum value of the dependent variable LE (72.59 years) happened in 2019. It has been observed that LE, GNI, and employment rates all rise with one another. There exists an adverse relationship between LE and age dependency ratio. Based on comparisons with other highly developed nations, Bangladesh's GNI needs to grow faster than other significant factors to boost life expectancy. We have forecasted variables that were significantly related to LE until 2030 for the purpose of sustainable development goals, especially the 3rd goal.

Glassy dynamics in bacterial growth rate temperature dependence

An empirical expression for the temperature dependence of bacterial growth rate, k=b(T−T0), where k is the intrinsic growth rate, T is the ambient temperature, T0 is the hypothetical temperature, and b is the regression coefficient, has been exemplified for practical bacterial growth. Although this relationship has been popularly used as the standard evaluation of the bacterial growth rate, its scientific foundation is not clear. We propose a new relation, k = k0 exp[−Ea/kB(T − Tc)], where k0 is a constant, Ea is the activation energy (eV), kB is the Boltzmann constant, T is the absolute temperature (K), and Tc is the characteristic (frozen-in) temperature (K). The present equation resembles that for temperature-dependent fluidity (inverse viscosity) originally found for glass-forming liquids in inorganic materials. This commonality is attributed to the glass-like properties of the bacterial cytoplasm in accordance with the recent findings of glassy dynamics in active or lived matter.

Thin-film (Al)BCN materials synthesized by sequential precursor pulses to mimic atomic layer deposition

This work brings novel insights into the existing knowledge on the deposition of films containing boron (B), carbon (C), nitrogen (N), and aluminum (Al). The (Al)BCN films are obtained at low substrate temperatures (TS) of 250–400 °C from triethylborane, ammonia (NH3), and trimethylaluminum. For BCN films, a nearly similar elemental composition of B0.42C0.41N0.15O0.02, with 1–2 at. % variations, is observed for substantial ranges of TS and NH3-exposure time. This can indicate a similar growth mechanism and/or formation of a single-phase material. While excluding precursor underdosing, a remarkable dependence of growth rate per cycle (GPC) on total gas pressure (Ptot) is observed. The GPC approaches near saturation regime for Ptot between 1 and 10 mbar, for TS = 330–375 °C, which might support the occurrence of a surface-adduct assisted pathway. The level of GPC saturation is influenced by TS. For a wide range of process conditions, N-share in the films slightly varies between 12 and 16 at. %. C-share only changes between 40 and 42 at. %. The attempt to increase N-share by dissociating NH3 into NH2 radicals by hot wire assistance remarkably shows the opposite effect, i.e., a decrease in the N-share from 15 to 6 at. %. This is accompanied by a corresponding increase in the B- and, in particular, C-shares, suggesting that the removal of carbon can occur via the incorporation of nitrogen. For AlBCN films, changing Ptot has a strong effect on their elemental composition. At Ptot = 10 mbar, Al-deficient films grow, whereas a Ptot of 0.2 mbar leads to mainly AlN-containing films with some inclusions of BN.

Cherenkov terahertz surface magnetoplasmons excitation by an electron beam

We developed the scheme of terahertz (THz) surface magnetoplasmons (SMPs) over n-type semiconductor by an electron beam in the presence of an external magnetic field. Electron beam bunching by SMPs generates perturbed current density and develops THz SMPs by resonant Cherenkov interaction. More beam energy is required for the generation of high-frequency THz SMPs in the presence of large applied magnetic field. Growth rate of Cherenkov THz SMPs grows with THz frequency and attains a maximum value and then falls off with THz frequency. It grows with temperature and decreases with the electron cyclotron frequency. Growth rate is directly proportional to beam density's cube root and inversely proportional to γ0b, where γ0b is relativistic factor of incident electron beam. The proposed mechanism may develop an actively tunable device for the generation of THz SMPs due to growth rate dependence on semiconductor temperature, applied magnetic field, and electron beam energy. The beam energy of 212.31–222.03 keV is used for the excitation of SMPs 0.81–2.3 THz.

Dependence of Pit Growth Rate on Applied Potential and Chloride Concentration under Conditions with and without Fluid Flow

Pitting corrosion on stainless steel is one of the most serious problems caused by seawater intrusion into power plants because it possibly perforates boundary structures, such as piping or containers, and leads to solution leakage. Although the evaluation of the pit growth rate in accordance with the corrosion condition is required to secure the plant’s safety, the dependence of the pit growth rate on various corrosion conditions is not fully understood. In this study, the effects of applied potential and chloride concentration on the pit growth rate on Type 304L stainless steel were assessed with and without fluid flow by performing the pit penetration test with in situ observations of pit initiation and penetration. An artificial one-dimensional pit experiment was performed to obtain a fundamental understanding of pit growth with and without fluid flow. In addition, three-dimensional pit growth behavior was further analyzed by measuring a dissolution current of a single three-dimensional pit. In the pit penetration test, the effects of applied potential and chloride concentration on the pit growth rate differed depending on the fluid flow condition; the pit growth rate is almost independent of the applied potential and chloride concentration without fluid flow, whereas the growth rate was decreased by decreasing the potential and chloride concentration with fluid flow. For the results of the artificial one-dimensional pit experiment, regardless of the fluid flow condition, stable pit growth in the depth direction was suggested to be diffusion-controlled. Measuring the time variation of the dissolution current of a single three-dimensional pit indicated that the three-dimensional pit growth involves temporary passivation and reactivation, which depend on the fluid flow condition and applied potential. This suggested pit growth in the pit penetration test proceeded discontinuously depending on the corrosion conditions, resulting in a dependence of the pit growth rate on the corrosion conditions.

Оценка скорости развития трещин и ресурса магистральных трубопроводов

In this article, based on determining strain parameters such as the equivalent (von Mises) strain and average strain, calculations of the depth growth rate of fatigue and stress-corrosion cracks as well as the operating life of the pipeline sections are performed. The results are presented as the operating time to failure and cycles number to failure by loading internal pressure. The obtained graphs of the dependence of the crack growth rate, crack depth, equivalent (von Mises) strain, average strain in the defective zone on the pipeline operation time are presented. During computational experiments for the main pipeline the destructive depth of defects, the residual operating life of the pipeline with cracks having different initial depth and length were determined.

Региональные факторы роста производства зерна в России

The record gross grain harvest in 2022 made it possible to strengthen Russia’s food security and increase its export potential. This increases the relevance of the study of regional factors of grain production growth to maintain this trend. A study of 27 regions with the most developed grain subcomplex, which produce almost 90% of grain in the country, showed a low dependence of grain production growth rates on the value of indicators of material and financial security of agriculture. It is concluded that a ranked increase in the growth rate of grain production in almost half of the regions occurred with a decrease in the staffing of enterprises with basic types of agricultural machinery, a decrease in the volume of mineral and organic fertilizers, a reduction in the volume of investment and subsidization of agriculture and an increase in the degree of general and complete depreciation of fixed assets of agriculture. Over the past eight years, the indicators of material and financial security of agriculture in all surveyed regions have sharply decreased, which significantly reduces the possibility of further growth in grain production. The selected regions were grouped according to the existing level of agricultural production potential. It was revealed that only ten regions have a relatively balanced material and financial potential, which makes it possible to continue increasing grain production in the near future with a high probability while maintaining the existing volumes of state support. In the remaining seventeen regions, further increase in grain production will be impossible without a significant increase in support and financing of the grain subcomplex.

High-amplitude effect on single-mode Richtmyer–Meshkov instability of a light–heavy interface

The high-amplitude effect on the Richtmyer–Meshkov instability flow characteristics is investigated by examining the interaction of a planar shock with a single-mode air–SF6 interface both experimentally and numerically. In our experiments, the soap–film technique is adopted to generate well-defined initial interfaces, and the shocked flows are recorded by high-speed schlieren photography. Numerical simulations are performed to highlight the effects of wave patterns on interface movements at the early stage. For cases with high initial amplitudes, a cavity is formed at each spike tip. The cavity formation is ascribed to the vorticity deposition on the slip lines resulting from the Mach reflection of the transmitted shock wave. A series of transverse shocks introduce the secondary compression effect, which changes the interface morphology and causes the failure of the impulsive model in predicting the amplitude linear growth rate. Those modified linear models considering a reduction factor are also found incapable of accurately predicting the linear growth rate. Moreover, a non-monotone dependence of linear growth rate on initial amplitude is observed. Although similar observations were reported in previous numerical simulations, they have never been reported in experiments before. According to the pressure and velocity distributions, the effects of shock–shock interaction on the movements of the interface peak and trough are demonstrated, and the mechanism of non-monotone dependence is discussed. The validity of the existing nonlinear model proposed for predicting the development of a single-mode interface is further tested. It is shown that the applicability of the model worsens as the initial amplitude or dimensionless time increases.

The impact of institutional quality on economic growth: Evidence from post-soviet countries

The paper investigates the long-run impact of the institutional environment on economic growth for the sample of post-Soviet countries in 1996-2021. Using the Autoregressive Distributive Lag Model, we found that a U-shaped link exists between institutional quality and economic growth. Regarding the institutional quality dimensions, a similar link was observed for four out of six factors (POLSTAB, GOVEFF, RULELAW, CONTCORR). In contrast, the other two dimensions (REGQUAL, VOACC) exhibited inverted U-shaped impact on the dependent variable. Moreover, findings provide insight into the impact of control variables such as inflation (INF), openness (OPE), and population growth rate (POPGROWTH) on economic growth. More precisely, openness was found to have positive impact on the dependent variable, while inflation and population growth rate both had negative effect on economic growth. Based on these results, the paper suggests some policy implications for post-Soviet countries in terms of achieving economic growth by improving the institutional quality environment.

Effects of residual stress on orientation dependent fatigue crack growth rates in additively manufactured stainless steel

Localized heating and resulting temperature gradients during additive manufacturing (AM) create significant residual stress that influences mechanical behavior, such as fatigue performance. To quantify residual stress effects on fatigue crack growth in AM materials, crack growth rates parallel and perpendicular to the build direction in directed energy deposition (DED) Type 304L austenitic stainless steel were measured. The on-line crack compliance method was used to determine the residual stress intensity factor, Kres, while simultaneously collecting fatigue crack growth rate (FCGR) data. Constant applied alternating stress intensity factor (constant ΔKapp) tests revealed the primary influence on measured FCGR is the orientation dependent Kres. Critical analysis of the compliance data from decreasing ΔKapp tests was used to quantify Kres, which was then used to correct FCGR data in the near-threshold regime. Results demonstrated that the fatigue response of DED Type 304L is inherently similar to that of annealed wrought Type 304/304L.

Coherent tracer correlations in deep-sea corals and implications for biomineralization mechanisms underlying vital effects

Deep-sea corals are a useful archive of thermocline, intermediate, and deep waters in past oceans. However, application of traditional oceanographic tracers to deep-sea corals remains a challenge due to our insufficient understanding of their “vital effects”. Deep-sea corals are ideal test organisms to study the mechanism underlying vital effects generally, due to the large tracer gradients in individual corals living under relatively constant environmental conditions. Lessons learned from these corals might apply to other scleractinia and to marine calcifiers more generally. Here we present stable isotope, minor and trace metal (Me/Ca ratios) data in a suite of modern Desmophyllum dianthus specimens, collected over multiple spatial scales in individual corals (bulk, micromill, SIMS, NanoSIMS), with multi-proxy analyses made on the same material whenever possible. Spatially coherent Me/Ca correlations are observed in the fibrous aragonite of individual corals, including positive correlations between Mg/Ca, Li/Ca and B/Ca, as well as negative correlations between Mg/Ca and Sr/Ca, consistent with previous studies. We also for the first time document strong correlations between the isotopic (δ18O and δ13C) and elemental compositions of the skeletons, most notably a negative correlation between δ18O and Mg/Ca. The centers of calcification (COCs) in the coral skeletons show distinct tracer correlations from the aragonite fibers that possibly reflect a more complicated formation mechanism. We interpret the spatially coherent tracer correlations in deep-sea corals with a numerical model of coral calcification previously developed for stable isotopes that considers the role of the enzyme carbonic anhydrase in the calcification processs. With the carbonate chemistry in the model constrained by the stable isotope data, we are able to explain the observed Me/Ca correlations as well as their range of variability, as a result of internal pH elevation in the extracellular calcifying fluid (ECF) of the corals with limited Ca-pumping through the calicoblastic membrane. In particular, the positive Mg/Ca–B/Ca correlation in the fibrous aragonite suggests a borate (B(OH)4–) substitution for carbonate ion (CO32–) incorporation mechanism in biogenic aragonite. We also suggest the growth rate dependence of the incorporation of minor and trace elements based conceptually on an ion-by-ion growth model may help explain the absolute Me/Ca values in biogenic aragonites. Finally, we generally find more limited tracer variability in corals from undersaturated seawater compared to their counterparts from supersaturated conditions, suggesting a limit to their internal pH elevation in response to this environmental stress. Understanding the biomineralization mechanisms underlying the vital effects is important for better use of these tracers for paleoceanographic applications, and may shed light on the response of marine calcification to future ocean acidification.

Влияет ли распределение доходов между трудом и капиталом на экономический рост?

The work is devoted to obtaining quantitative estimates of the impact of the dis-tribution of income between labor and capital on the rate of economic growth in the modern world. We used UN data on a set of European countries, post-Soviet countries, Israel, Canada, the USA and Turkey. To assess the impact of the distribution of income between labor and capital on economic growth rates, linear econometric models of the dependence of economic growth rates on the share of labor force in GDP by years of the period from 2007 to 2019 built. The obtained results showed that the relationship between the rates of economic growth and the share of labor force in GDP in the mod-ern world is not significant, the influence of the share of labor force in GDP on econom-ic growth is negative, but declining obliquely, in recent years it has become insignificant. it can be expected that in the 2020s this influence may become positive. Outpacing wage growth rates can help increase labor productivity and accelerate economic growth in the transition to a post-industrial economy.

EXTH-16. THE ORAL IRON-MIMETIC GALLIUM MALTOLATE SUPPRESSES TREATMENT-RESISTANT GLIOBLASTOMA – IN VIVO VALIDATION

Abstract BACKGROUND We previously reported on our in vitro and in vivo studies using the metallocompound gallium maltolate (GaM) to target glioblastoma (GBM). We demonstrated a profound cytotoxic effect in vitrov and in vivo. Additionally, our preliminary in vivo data suggested a substantial inhibitory effect on tumor growth, as well as a significant extension of disease-specific survival (OS). Here, we further validate the inhibitory effects of GaM in vivo. METHODS In vitro irradiated adult GBM U87-MG cells were stereotactically implanted into the right striatum of male and female athymic rats. Advanced MR imaging at 9.4T was carried out weekly starting two weeks after implantation. Daily oral GaM (50 mg/kg) or vehicle were provided on tumor confirmation. Longitudinal advanced MRI parameters were processed for enhancing tumor ROIs in OsiriX 8.5.1 (lite) with Imaging Biometrics Software (Imaging Biometrics LLC,). Statistical analyses included Kaplan-Meier survival plots, linear mixed model (LMM) comparisons, and t-statistic for slopes comparison (as indicator of tumor growth rate). RESULTS Median OS for the male pilot cohort (5 control, 5 GaM) was 28 and 51 days, respectively; 31 and 59 days for the male replication cohort (1 control, 3 GaM); 37 and 48 days for the female replication cohort (6 control, 7 GaM). GaM-treated xenograft tumors grew significantly slower than control tumors with sex and time dependent growth rates. No significant differences were seen between male and female cohorts in both control and treatment groups at all timepoints. Hence, subsequent analyses were performed on pooled data. Median OS was 30.5 days and 48 days for control and GaM groups, respectively (p < .001). A strong correlation between treatment and survival (Χ2 = 6.238187; p = .0125) and tumor growth suppression (LMM; p < .0001) was evident. CONCLUSION We have successfully validated the inhibitory effects of GaM on GBM growth in vivo.

Cascading parametric decay coupling between whistler and ion acoustic waves: Darwin particle-in-cell simulations

We present the results of numerical studies of the whistler wave parametric decay instability in the system with the suppressed Landau damping of ion acoustic waves (IAWs) based on the self-consistent Darwin particle-in-cell (PIC) model. It has been demonstrated that a monochromatic whistler wave launched along the background magnetic field couples to a counter-propagating whistler mode and co-propagating ion acoustic mode. The coupling of the electromagnetic mode to the electrostatic mode is guided by a ponderomotive force that forms spatio-temporal beat patterns in the longitudinal electric field generated by the counter-propagating whistler and the pump whistler wave. The threshold amplitude for the instability is determined to be δBw/B0 = 0.028 and agrees with a prediction for the ion decay instability: δBw/B0 = 0.042 based on the linear kinetic damping rates, and δBw/B0 = 0.030 based on the simulation derived damping rates. Increasing the amplitude of the pump whistler wave, the secondary and tertiary decay thresholds are reached, and cascading parametric decay from the daughter whistler modes is observed. At the largest amplitude (δBw/B0 ∼ 0.1) the primary IAW evolves into a short-lived and highly nonlinear structure. The observed dependence of the IAW growth rate on the pump wave amplitude agrees with the expected trend; however, quantitatively, the growth rate of the IAW is larger than expected from theoretical predictions. We discuss the relevant space regimes where the instability could be observed and extensions to the parametric coupling of whistler waves with the electron acoustic wave (EAW).

Fractional dynamics and modulational instability in long-range Heisenberg chains

We study the effective dynamics of ferromagnetic spin chains in presence of long-range interactions. We consider the Heisenberg Hamiltonian in one dimension for which the spins are coupled through power-law long-range exchange interactions with exponent α. We add to the Hamiltonian an anisotropy in the z-direction. In the framework of a semiclassical approach, we use the Holstein–Primakoff transformation to derive an effective long-range discrete nonlinear Schrödinger equation. We then perform the continuum limit and we obtain a fractional nonlinear Schrödinger-like equation. Finally, we study the modulational instability of plane-waves in the continuum limit and we prove that, at variance with the short-range case, plane waves are modulationally unstable for α<3. We also study the dependence of the modulation instability growth rate and critical wave-number on the parameters of the Hamiltonian and on the exponent α.

Foreign Direct Investment and Exports Stimulate Economic Growth? Evidence of Equilibrium Relationship in Peru

The purpose of this research is to estimate the dynamic impacts of foreign direct investments (FDI) and exports on economic growth in Peru (1970–2020) using annual series. Starting with the theoretical Mundell–Fleming static model with assumptions, we find that the change in exports does not affect GDP, and the effect of FDI on GDP can be positive or negative depending on the comparison between the slopes of the IS and LM curves. The variables are foreign direct investment net flow (% of GDP), exports of goods and services (% of GDP), and GDP growth rate (%). FDI and exports constitute first-order integrated processes; meanwhile, the GDP growth rate is a stationary process. The Granger causality evidences feedback between GDP and exports and the FDI-led growth hypothesis. Considering the dependent variable GDP growth rate, the autoregressive distributed lag cointegration bound test shows the findings regarding the cointegration consist of positive long-term equilibrium impacts from exports and FDI on GDP. Estimating an error correction model, in the short-term, the FDI explains to GDP and the exports have an insignificant impact on economic growth in Peru. Finally, we conclude that Peru’s economic policy path should continue to attract foreign capital to increase FDI.

Stochastic line integrals and stream functions as metrics of irreversibility and heat transfer

Stochastic line integrals are presented as a useful metric for quantitatively characterizing irreversibility and detailed balance violation in noise-driven dynamical systems. A particular realization is the stochastic area, recently studied in coupled electrical circuits. Here we provide a general framework for understanding properties of stochastic line integrals and clarify their implementation for experiments and simulations. For two-dimensional systems, stochastic line integrals can be expressed in terms of a stream function, the sign of which determines the orientation of nonequilibrium steady-state probability currents. Theoretical results are supported by numerical studies of an overdamped two-dimensional mass-spring system driven out of equilibrium. Additionally, the stream function permits analytical understanding of the scaling dependence of stochastic area growth rate on key parameters such as the noise strength for both linear and nonlinear springs.