Mass Parameters Research Articles

Mass-redshift dependency of supermassive black hole binaries for the gravitational wave background

ABSTRACT Studying how the black hole (BH)–(galaxy) bulge mass relation evolves with redshift provides valuable insights into the co-evolution of supermassive black holes and their host galaxies. However, obtaining accurate measurement of BH masses is challenging due to the bias towards the most massive and luminous galaxies. Instead, we focus on the BH and bulge masses as they vary with redshift using the EAGLE, Illustris, TNG100, TNG300, Horizon-AGN, and SIMBA large-scale cosmological simulations. We use an analytical astrophysical model with galaxy stellar mass function, pair fraction, merger time-scale and BH–bulge mass relation extended to include redshift evolution. The model can predict the intensity of the gravitational wave background (GWB) produced by a population of supermassive black hole binary (SMBHB) as a function of the frequency. This allows us to compare the predictions of this model with the constraints of pulsar timing array observations. Here, we employ Bayesian analysis for the parameter inference. We find that all six simulations are consistent $\le 3.5\sigma$ with a range of simulated GWB spectra. By fixing the BH–bulge mass parameters to the simulations we analyse the changes in the constraints on the other astrophysical parameters. Furthermore, we also examine the variation in SMBHB merger rate with mass and redshift between these large-scale simulations.

Analysis and development of criteria for the operational efficiency of urban electric buses

Problem. Currently, manufacturers and research specialists primarily utilize the amount of autonomous mileage and/or the specific electricity consumption of autonomous DEEs per unit of mileage to describe the general characteristics of urban electric buses. However, the structural mass and the key operational parameter, the nominal passenger capacity, are often disregarded. Therefore, comparing electric buses of the same type with identical dimensional parameters based solely on these criteria is illogical and incorrect. Goal. This study aims to establish criteria for the operational efficiency of urban low-floor electric buses of various types, considering autonomous DEE and their charging or replacement systems. These criteria should account for structural mass and nominal passenger capacity, facilitating a proper comparative assessment and the selection of the most optimal options for use in urban passenger transportation systems. Methodology. Criteria for the operational efficiency of city electric buses of various types are proposed based on an analysis of electricity consumption required for both movement and the operation of heating, ventilation, and air conditioning systems. The criteria consider the mass in the equipped state and the main parameter - nominal passenger capacity. Results. Several operational efficiency criteria for urban electric buses, incorporating mass parameters and passenger capacity, are suggested. The feasibility of their application is demonstrated through a comparison of five sketch projects of electric buses of various types with modern models. Originality. The proposed criteria for the operational efficiency of urban electric buses offer a method for adequately comparing any selected models, regardless of their types and technical specifications. Practical value. The proposed criteria for the operational efficiency of urban electric buses of various types can be beneficial for transport company specialists in selecting suitable rolling stock for specific routes. Additionally, design bureau and scientific and technical center specialists can utilize these criteria during the design process of new urban electric transport models.

Mechanism Analysis of the Effect of Wake Vortex on Cylinder Vibration in Flow Induced Motion

Abstract Unsteady Reynolds-averaged Navier–Stokes (RANS) method combined with Spalart–Allmaras turbulence model and dynamic mesh technology was used to investigate the impact of wake vortex on the vibration response of a cylinder. By analyzing the phase difference between the wake vortex force and the displacement under different mass parameters in flow-induced vibration (FIV), the study reveals that the influence of wake vortex on the cylinder varies significantly in different vibration branches. The wake vortex of the initial branch enhances the cylinder's vibration, whereas the wake vortices of the upper, lower, and desynchronized branches suppress the vibration. At the critical point between the initial branch and the upper branch of vortex-induced vibration (VIV), there is a 90 degree phase jump, and the instantaneous phase difference fluctuation between the wake vortex force and displacement of the VIV branch remains relatively constant. In the galloping branch, there are wake vortices in different directions that affect the cylinder's vibration every quarter of the vibration period, and the phase difference undergoes periodic large fluctuations (either in-phase or out-of-phase), with the result that the wake vortex force periodically promotes or restrains the cylinder's vibration, which can serve as a novel criterion for identifying the occurrence of galloping. Furthermore, when varying the mass parameters at a constant reduced velocity, the impact of the wake vortex in the initial branch is relatively insignificant. However, as the mass ratio increases in other vibration branches, the suppressive effect increases, and the wake vortex force can prevent VIV induced galloping phenomenon by affecting the vibration intensity.

Brazil nut–enriched diet modulates bone mineral density and body composition in an experimental model of chronic kidney disease

ObjectiveThis study investigates the effects of a Brazil nut-enriched diet on body composition and bone parameters in CKD animal model. MethodsMale Wistar rats were assigned to the following groups: Sham (n=8), Nx (n=6), nephrectomized rats, and NxBN (n=6), nephrectomized rats and an enricheddiet with 5% Brazil nut. Body composition parameters were obtained by dual-energy X- ray absorptiometry (DXA). Bioclin kits determined plasmatic calcium. The femurs werecollected to determine absolute mass and length, bone mineral density, and biomechanical tests. ResultsThe NxBN group exhibited a higher total body bone mineral density (BMD) value than the Nx group (0.177±0.004g/cm2vs 0,169±0.003g/cm2; p=0.0397). No significant differences were observed regarding absolute mass, length, BMD, and biomechanical parameters in the femurs of the groups. Moreover, no significant differences were found in plasmatic calcium levels among the groups. ConclusionsBrazil-nut enriched diet modulated BMD in CKD experimental model, and further studies are demanded to understand the pathways involved in this finding.

Quark and proton anomalous magnetic moments in confining models

We compute the one-loop quark-photon vertex and the quark magnetic moment in three different models with an infrared-modified gluon propagator, namely: the massive (Curci-Ferrari-like) model, the Gribov-Zwanziger model, and the refined Gribov-Zwanziger model. We show results for the F2 form factor and analyze the role played by the mass parameters associated with the confined gluon in these models. Using the framework of the constituent quark model, we further construct the observable proton magnetic moment including the effects of quantum chromodynamics (QCD) interactions generated by the different confining models. Our results show that there is no qualitative observable difference stemming from the presence of complex-conjugated poles. On the other hand, quantitative differences between the various confining models can be sizable, so that observable constraints would in principle be possible, provided one has sufficient information about the constituent quark mass and the QCD running coupling. Published by the American Physical Society 2024

FIRST COMPREHENSIVE ECHOCARDIOGRAPHIC ASSESSMENT IN PATIENTS WITH VASCULAR EHLERS-DANLOS SYNDROME WITH OR WITHOUT CELIPROLOL THERAPY AT THE MAXIMUM RECOMMENDED DOSE

Objective: Vascular Ehlers-Danlos syndrome (vEDS) is an inherited connective tissue disorder characterized by arterial fragility. Celiprolol is a beta1-adrenoceptor antagonist with partial beta2 agonist activity that has been shown to reduce rates of vascular events in this setting, though the underlying mechanisms are not yet fully understood. Moreover, few data on echocardiographic assessment are available in patients with vEDS. Design and method: Twenty patients with genetically confirmed diagnosis of vEDS followed at our Institution were divided into two groups (10 patients each) according to whether or not they were on celiprolol therapy at the maximum recommended dose (400 mg daily) for at least 12 months. Both groups were compared to 10 healthy individuals matched for sex, age, body mass index (BMI), and office blood pressure values. Each participant underwent transthoracic echocardiography with tissue Doppler analysis for a comprehensive evaluation of cardiac structure and function. Results: Mean age was 35 years and mean BMI was 21.6 kg/m2. Female sex was prevalent (60%). Left ventricular (LV) internal diameter values tended to be lower in patients with untreated vEDS than in healthy controls, though this difference was not statistically significant (4.33 vs 4.74 cm, respectively; p=0.053). Similar data were observed for LV mass index (56.9 vs 68.6 g/m2; p=0.093), stroke volume (56.6 vs 71.6 mL; p=0.068), and E/A ratio (1.26 vs 1.66; p=0.082), whereas an opposite trend was observed for e’ lateral (13.2 vs 12.2; p=0.096). No statistically significant difference was found between groups in terms of other parameters of LV mass, systolic and diastolic function. A normal LV geometry was found in all the cases. Indices of mechano-energetic efficiency and ventricular-arterial coupling were also similar between groups. No patient presented with aortic root dilation, mitral valve prolapse, valve insufficiency of more than mild degree, or valve stenosis of any degree. Conclusions: Our study suggests that patients with vEDS have normal cardiac mass and geometry, as well as normal systolic and diastolic function. Celiprolol therapy does not seem to significantly influence such aspects. Future studies on larger cohort of patients should confirm these aspects.

A study of the equilibrium dynamics of the test particle in the collinear circular restricted four-body problem with non-spherical central primary

We consider the collinear restricted four-body problem (CR4BP), where the test particle of infinitesimal mass is moving under the gravitational influence of the three primary bodies. It is further assumed that the central primary is a non-spherical body, particularly either an oblate or prolate spheroid, whereas the peripheral primaries are spherical in shape. A numerical analysis is presented to unveil the effect of the oblateness and prolateness parameters on the position of equilibrium points (EPs) and their linear stability in the CR4BP. Moreover, the permissible regions of possible motion as determined by the zero-velocity surface and associated equipotential curves and the basins of convergence linked with the EPs on the orbital plane are presented. The existence and number of collinear EPs and non-collinear EPs in the problem depend on the combination of the mass parameter of the primaries and the oblateness/prolateness parameter. Additionally, the application of the problem in the Saturn-Moon(1)-Moon(2)-System has been presented.

TriOS Schwarzschild Orbit Modeling: Robustness of Parameter Inference for Masses and Shapes of Triaxial Galaxies with Supermassive Black Holes

Evidence for the majority of the supermassive black holes in the local Universe has been obtained dynamically from stellar motions with the Schwarzschild orbit superposition method. However, there have been only a handful of studies using simulated data to examine the ability of this method to reliably recover known input black hole masses M BH and other galaxy parameters. Here, we conduct a comprehensive assessment of the reliability of the triaxial Schwarzschild method at simultaneously determining M BH, stellar mass-to-light ratio M*/L, dark matter mass, and three intrinsic triaxial shape parameters of simulated galaxies. For each of 25 rounds of mock observations using simulated stellar kinematics and the TriOS code, we derive best-fitting parameters and confidence intervals after a full search in the 6D parameter space with our likelihood-based model inference scheme. The two key mass parameters, M BH and M*/L, are recovered within the 68% confidence interval, and other parameters are recovered between the 68% and 95% confidence intervals. The spatially varying velocity anisotropy of the stellar orbits is also well recovered. We explore whether the goodness-of-fit measure used for galaxy model selection in our pipeline is biased by variable complexity across the 6D parameter space. In our tests, adding a penalty term to the likelihood measure either makes little difference, or worsens the recovery in some cases.

An experimental study on thermal runaway propagation over cyclic aging lithium-ion battery modules with different electrical connections

This paper investigates the thermal runaway propagation characteristics of cyclic aging battery modules connected in series, parallel, and series-parallel configurations. Additionally, a comparative analysis of the thermal runaway characteristics among the three battery module configurations is performed. In this experiment, voltage, mass, and other parameters of cells are measured. The temperature response reveals that: when comparing the three battery module configurations, the parallel module has the highest maximum temperature of thermal runaway at 720 °C, followed by the series and series-parallel combined configurations at 683 °C and 669 °C, respectively. The parallel module also exhibits the fastest propagation rate of thermal runaway, which is further intensified by cyclic aging. Regarding the voltage response: the series configuration has five stages of voltage variation during thermal runaway, while the parallel configuration has two stages, and the series-parallel combined configuration has three stages. Cyclic aging accelerates the voltage decline during thermal runaway for all three battery module types. In terms of mass response: the 2P2S configuration experiences the highest mass loss of 55.7 g, followed by the parallel (40.8 g) and series (34.7 g) configurations. Preliminary heat transfer analysis shows that: the average heat transfer during thermal runaway is highest for the 2P2S configuration (20,161 J), followed by the 4S (18,913 J) and 4P (18,773 J) configurations. Cyclic aging reduces the overall heat transfer. Electrical connections have minimal impact on heat transfer within the battery modules. Specifically, in the 4S, 4P, and 2P2S configurations, the heat transfer attributed to electrical connections accounts for only 1.2 %, 0.4 %, and 7.3 % respectively, of the overall heat conduction through the battery shell.

The Dynamical Equations of the Restricted Three-Body Problem with Poynting-Robertson Drag Force and Variable Masses

The restricted three-body problem (R3BP) is a formulation which defines the motion of a passively gravitating test particle having infinitesimal mass and moving in the gravitational environment of two bodies, called primaries. The R3BP is still an exciting and active research field that has been getting attention of scientists and astronomers because of its applications in dynamics of the solar and stellar systems, lunar theory, and artificial satellites. The equations of motion are usually the starting point in the investigations of the dynamical predictions of the infinitesimal mass. Therefore, in this paper, we examine the derivations of the dynamical equations of the R3BP with Poynting-Robertson (P-R) Drag force and variable masses. In this model formulation, both primaries are assumed to vary their masses under the combined Mestschersky law (CML) and they move in the frame of the GyldenMestschersky equation (GME). Further, the bigger primary is assumed to be emitting radiation force, which is a component of the radiation pressure and the P-R drag. The non- autonomous dynamical equations of the model are derived and converted into the autonomized equations with constant coefficients using the Mestschersky transformation (MT), the CML, the particular solutions of the GMP, and a transformation for the time dependent velocity of light. We observed that the P-R drag of the bigger primary depends on the mass parameter, radiation pressure, velocity of light and the mass variation constant . The derived systems of equations with variable and constant coefficients can be used to model the long-term motion of satellites and planets in binary systems.

To the question of construction of welding inverter sources with a high power factor

Purpose. Design a power-factor-corrected, energy- and cost-efficient switchmode power supply for welding. Methodology. It is proposed to use the principle of direct conversion and to develop the "hybrid" power circuit consisting of a main power path using direct conversion and an auxiliary power path having a converter with an intermediate DC link with relatively low stored energy. Since a load to the welding power supply is the welding arc, its instantaneous power fluctuations during the mains voltage period essentially do not influence the welding process due to the thermal constant of the weld pool molten metal. Effective use of this features of the welding arc allows to optimize the power processing, reduce the amount of energy stored in the reactive elements of the circuit and improve the economical, mass and dimensional parameters of the supplies. Findings. A new power factor corrected switchmode power supply topology is proposed utilizing beforementioned principles of power processing. The algorithm for calculating the switching frequency of supply power switches is given. To confirm the adequacy of the developed provisions, an experimental sample of the power supply was created. Oscillograms of mains voltage and source current consumption and oscillograms in output current limitation mode are obtained. The results of experiments showed that the supply has a power factor > 0.94 in a wide range of powers. Originality. A distinctive feature of the supply is the absence of additional inductive components in the power path, a lower capacitance of the DC-link bulk capacitor and a simplified scheme for limiting its inrush current during initial charging. The supply has an increased open circuit voltage, independent of the mains voltage, which allows for easy arc ignition during manual arc welding. Practical value. Due to the increased power factor, the current drawn from the mains is 30 % to 45 % lower than that of widespread inverter supplies without a power factor corrector. These features allow to simultaneously use more power supply units with the same mains current load, and/or to provide stable welding in conditions of a "weak" mains.

A Kustaanheimo–Stiefel regularization of the elliptic restricted three-body problem and the detection of close encounters with fast Lyapunov indicators

We present the Kustaanheimo–Stiefel (KS) regularization of the elliptic restricted three-body problem (ER3BP) at the secondary body P2, and discuss its use to study a category of transits through its Hill’s sphere (fast close encounters). Starting from the Hamiltonian representation of the problem using the synodic rotating–pulsating reference frame and the true anomaly of P2 as independent variable, we perform the regularization at the secondary body analogous to the circular case by applying the classical KS transformation and the iso-energetic reduction in an extended 10-dimensional phase-space; this translates into an efficient algorithm that can be readily implemented to numerically integrate the equations of motion. Using such a regularized Hamiltonian we recover a definition of fast close encounters in the ER3BP for small values of the mass parameter μ (while we do not require a smallness condition on the eccentricity of the primaries), and we show that for these encounters the solutions of the variational equations are characterized by an exponential growth during the fast transits through the Hill’s sphere. Thus, for small μ, we justify the effectiveness of the regularized fast Lyapunov indicators (RFLIs) to detect orbits with multiple fast close encounters. Finally, we provide numerical demonstrations and show the benefits of the regularization in terms of the computational cost.

Optimising the steering clutch of a walking tractor using soft computing approaches

ABSTRACT Walking tractors are often used for weeding gardens, small fields, vineyards, and greenhouses. The clutch fork arm (CFA), which is used on the rotary axle, is subject to high loads. Therefore, an optimal design must be carried out under all load conditions while minimising weight. The present study aims to reduce the mass and load acting on the CFA and increase its safety factor. To achieve an optimal design, this study used the dimensions of the CFA as independent variables and the mass and maximum load exerted on the CFA as dependent variables. Multi-linear regression (MLR) and Artificial Neural Network (ANN) models were then developed. MLR and ANN models were proposed to predict the mass and load acting on the CFA. The proposed models were trained and validated using a dataset containing dimensions, mass parameters and maximum stresses for eighty-one CFA specimens based on the results of the finite element method (FEM). Based on the optimised structural properties, a FEM model of the CFA was then developed in Ansys R19.2. The results showed that the maximum absolute difference in stresses from the FEM and ANN models was less than 3.7%, while for mass it was less than 2.2%. Furthermore, the maximum reduction in mass and increase in safety factor were achieved by 52.0% (from 1.3 kg to 0.62 kg) and 36.0% (from 1.28 to 1.64), respectively. Therefore, these results were a confirmation of the ANN model to use as an alternative to the FEM method.

Capillary Imbibition Laws of Fresh–Brackish Waters in Sandstone

Understanding the capillary imbibition laws of brackish water in rocks is necessary to reveal the mechanism of fluid, salt, and ion transport. In this study, we investigated the capillary imbibition laws of a Na2SO4 solution of different concentrations in sandstone by measuring the parameters of water absorption mass, water migration front height, nuclear magnetic resonance (NMR) T2 spectra, and stratified moisture distribution. The results indicate the following: (1) With an increase in the salt solution concentration, the water absorption rate of samples increases, specifically manifested in an increase in the rate of absorption mass and a rising rate of the absorption front. (2) With an increase in the salt solution concentration, the total NMR signals in samples measured at the end of water absorption decreases; that is, the total amount of water absorption decreases. (3) When the solution concentration exceeds 0.50 g/L, variations in the NMR signal of samples and the absorbed water mass over time are not synchronic and are even opposite at some stages. Based on the capillary dynamic theories of liquid, the influence of salts on solution properties and the modification of the pore structure by crystallization are considered when discussing the underlying mechanism of capillary imbibition in sandstone. By calculating the physical properties such as the density, viscosity, surface tension, and contact angle of solutions with different concentrations, the imbibition process does not exhibit any significant variation with the difference in the properties of the liquid. The equivalent capillary radii of the samples at varying salt concentrations are obtained by fitting the capillary dynamics curves with the theoretically calculated values. The equivalent capillary radii of samples in higher salt concentrations are larger, i.e., the difference in capillary imbibition laws introduced by the salt concentration should be attributed to modifications to the pore structure caused by salt crystallization.

Experimental Validation of Comprehensive Calculation for High-Resolution Linear MALDI-TOF Mass Spectrometry.

This work discusses the effectiveness of the previously developed comprehensive calculation model to optimize linear MALDI-TOF mass spectrometers. The model couples space- and velocity-focusing to precisely analyze the flight-time distribution of ions and predict optimal experimental parameters for the highest mass resolving power. Experimental validation was conducted using a laboratory-made instrument to analyze CsI3 and angiotensin I ions in low to medium m/z range. The results indicate that the predicted optimal extraction voltage and delay were reasonably accurate and effective. In the low m/z range, the peak width obtained using optimal parameters reached the sub nanosecond range, corresponding to a mass resolving power of 10 000-17 000, or 20 000-34 000 if shot-to-shot random fluctuations were minimized by the dynamic data correction method. The observed optimal mass resolving power in the current experiment is 4.8-7.8 times that of commercial instruments. Practical limitations resulting in the gap between the observed and theoretical ultimate mass resolving power are discussed.

Dark Matter searches with photons at the LHC

We unveil blind spot regions in dark matter (DM) direct detection (DMDD), for weakly interacting massive particles with a mass around a few hundred GeV that may reveal interesting photon signals at the LHC. We explore a scenario where the DM primarily originates from the singlet sector within the Z3-symmetric Next-to-Minimal Supersymmetric Standard Model (NMSSM). A novel DMDD spin-independent blind spot condition is revealed for singlino-dominated DM, in cases where the mass parameters of the higgsino and the singlino-dominated lightest supersymmetric particle (LSP) exhibit opposite relative signs (i.e., κ < 0), emphasizing the role of nearby bino and higgsino-like states in tempering the singlino-dominated LSP. Additionally, proximate bino and/or higgsino states can act as co-annihilation partner(s) for singlino-dominated DM, ensuring agreement with the observed relic abundance of DM. Remarkably, in scenarios involving singlino-higgsino co-annihilation, higgsino-like neutralinos can distinctly favor radiative decay modes into the singlino-dominated LSP and a photon, as opposed to decays into leptons/hadrons. In exploring this region of parameter space within the singlino-higgsino compressed scenario, we study the signal associated with at least one relatively soft photon alongside a lepton, accompanied by substantial missing transverse energy (ɆT) and a hard initial state radiation jet at the LHC. In the context of singlino-bino co-annihilation, the bino state, as the next-to-LSP, exhibits significant radiative decay into a soft photon and the LSP, enabling the possible exploration at the LHC through the triggering of this soft photon alongside large ɆT and relatively hard leptons/jets resulting from the decay of heavier higgsino-like states.

Development and Analysis of Novel Integrable Nonlinear Dynamical Systems on Quasi-One-Dimensional Lattices. Two-Component Nonlinear System with the On-Site and Spatially Distributed Inertial Mass Parameters

The main principles of developing the evolutionary nonlinear integrable systems on quasi-onedimensional lattices are formulated in clear mathematical and physical terms discarding the whimsical mathematical formulations and computer-addicted presentations. These basic principles are substantiated by the actual development of novel semi-discrete integrable nonlinear system, whose auxiliary spectral and evolutionary operators are given by 4 × 4 square matrices. The procedure of reduction from the prototype nonlinear integrable system with twelve field functions to the physically meaningful nonlinear integrable system with four field functions is described in details prompted by our previous cumulative experience. The obtained ultimate semi-discrete nonlinear integrable system comprises the two subsystems of essentially distinct physical origins. Thus, the first subsystem is the subsystem of the Toda type. It is characterized by the on-site (spatially local) mass parameter and the positively defined elasticity coefficient. In contrast, the second subsystem is characterized by the spatially distributed mass parameters and the negatively defined elasticity coefficient responsible for the low-amplitude instability. We believe our scrupulous consideration of all main steps in developing the semidiscrete nonlinear integrable systems will be useful for the researchers unfamiliar with the numerous stumbling blocks inevitable in such an interesting and prospective scientific field as the theory of semi-discrete nonlinear integrable systems.

Optimization of a vibro-impact damper design using MATLAB tools

The paper studies the dynamics of a vibro-impact system consisting of a main (primary) structure and a vibro-impact damper coupled to it. A vibro-impact damper is a vibro-impact nonlinear energy sink (VI NES). The optimal damper design should provide the best vibration mitigation for the primary structure. The optimization procedures for finding the optimal NES design are carried out using standard MATLAB tools. We used different MATLAB programs, namely surf program, which graphically shows the ranges of parameter pairs to be optimized; fminsearch and fminconprograms, which search for local minima of the objective function. It is shown that the optimization procedure itself is ambiguous and contains a sufficient amount of arbitrariness. Its result is also ambiguous. It is due to the presence of the many possible sets of damper parameters that can provide maximum mitigation of the main structure vibrations. We do not use the genetic algorithm gabecause it selects random intermediate results and yields randomly selected parameter sets from the optimal parameters manifold. Setting the objective function and its parameters plays a crucial role in the optimization process. We have chosen the maximum total energy of the primary structure as the objective function. Each resulting variant of the damper parameter set should be carefully tested and analyzed. We compared the five obtained optimal designs for dampers with two different masses. When analyzing them, we observed different motion modes, namely periodic modes of different periodicity with different number of impacts per cycle, with different ratio of bodies motion periods: 1:1 resonance with resonance capture and 2:1 resonance; amulti-periodic mode with many impacts per cycle, which turned out to be an amplitude-modulated mode – Amplitude Modulated Signal . The final decision on the optimal damper design may be made taking into account various engineering considerations regarding its mass and other parameters. It should be based on the options obtained as a result of the optimization procedure.

The impact of guideline recommended protein intake on mortality and length of intensive care unit and hospital stay in critically ill adults: A systematic review

International guidelines recommend a target protein intake of ≥1.2 g/kg/day to all critically ill patients for optimal outcomes. There are however various conflicting data related to this recommendation. The primary objective of this review was to compare a protein intake group (≥1.2 g/kg/day) with a lower protein intake group (<1.2 g/kg/day) in critically ill adult patients on mortality, length of intensive care unit (ICU) and hospital stay. Secondly, the effect of protein intake on length of mechanical ventilation, adverse nutrition-related events and muscle mass and strength parameters were investigated. Sixteen randomised controlled trials (RCTs) of adult patients admitted to an intensive or high care unit and receiving nutrition support in the form of enteral- and/or parenteral nutrition were selected against prespecified eligibility criteria. Two independent reviewers extracted relevant data and assessed the risk of bias of the included studies. Review Manager 5.4.1 was used to analyse data and GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) was used to evaluate the certainty of the evidence. The higher protein group, when compared to the lower protein group, probably results in little to no difference in mortality (risk ratio [RR] 1.01; 95% confidence interval [CI]: 0.89 to 1.14; moderate-certainty evidence); with a probable slight increase in length of ICU stay (mean difference [MD] 0.33; 95% CI -0.57 to 1.23; moderate-certainty) and length of hospital stay (MD 1.72; 95% CI -0.58 to 4.01; moderate-certainty evidence), on average. For secondary outcomes, it was found that the higher protein group probably does not reduce the length of mechanical ventilation (MD 0.08; 95% CI -0.38 to 0.53; moderate-certainty evidence). Higher protein group probably reduces the occurrence of diarrhoea and high gastric residual volume and may reduce the occurrence of constipation. It may also increase nitrogen balance (MD 3.66; 95% CI 1.81 to 5.51; low-certainty evidence). Importantly, there does not seem to be harm associated with the higher protein group, though it should be mentioned that for many of the adverse events in this study, the certainty of evidence was low or very low.

Study on the influence of orthogonal double pendulum on the ice shedding of transmission lines

ABSTRACT Ice shedding and vibration of ice-covered transmission lines can pose a serious threat to the safe operation of power lines in heavy ice areas. However, the common preventative practice of installing anti-vibration hammers, spacers and other devices on the line has limited effects on the safe operation of transmission lines. This paper focused on the simulation and experimental study of the influence of orthogonal double pendulum damper, a new type of anti-vibration device for transmission lines, on the ice shedding and vibration reduction of transmission lines. The 3-DOF calculation model of the orthogonal double pendulum damper was established, and the influence of the parameters of orthogonal double pendulum damper on the ice shedding of the line was simulated and analysed. In addition, natural ice shedding tests of lines were carried out at Xuefeng Mountain National Field Station, and ice shedding and vibration displacement response of lines was measured after the installation of orthogonal double pendulum dampers. The results showed that The three main structural parameters of mass, pendulum length and arm length can affect the maximum amplitude of ice shedding and vibration of transmission lines. The mass of the hammerhead has an effect on the vibration in both vertical and horizontal directions; the pendulum length mainly affects the vibration of the line in the horizontal direction; the arm length mainly affects the vibration in the vertical direction.