bluuebunny/crossref_metadata_2025 huggingface dataset:
A Transient Infinite Element for Multi-Dimensional Acoustic Radiation
Authors: Astley R. Jeremy
Published: March 2021

A novel family of infinite “wave envelope” elements is proposed for the solution of transient wave problems in unbounded regions. The elements are formed by applying an inverse Fourier transformation to a discrete wave envelope model in the frequency domain. This gives a coupled system of second-order equations which are readily integrated in time to yield transient pressure histories at nodal points on the surface of the radiating body and — in retarded form — at discrete points within the infinite domain. The infinite elements formed in this way can be applied quite generally to two-dimensional and three-dimensional problems and are fully compatible with conventional finite acoustical elements. They can be used to model radiating bodies of arbitrary shape but are demonstrated in the current instance in application to test problems which involve sound fields generated by spherical surfaces excited from rest, the exterior region being modeled by finite and infinite elements with explicit transverse interpolation. The computed transient solutions obtained from this formulation are compared to analytic solutions and shown to yield accurate results over a full range of exciting frequencies. The utility of the method for problems which involve broadband excitation is confirmed by comparisons of computed and analytic surface impedances for the steady harmonic case. These indicate that the accuracy of the scheme is limited only by a requirement to match element order to the highest order multi-pole component present in the radiated field. That is to say, elements of radial order 1 give an exact solution for monopole fields at all frequencies; elements of order 2 give an exact solution for dipole fields; elements of order 3 give an exact solution for quadrupole fields and so on. Similar results are presented for the fully three dimensional case. These support the extension of this hypothesis to three dimensional transient solutions subject only to the normal limitations imposed by spatial resolution in the transverse direction.
Vibration Control of Rotor Systems With Noncollocated Sensor/Actuator by Experimental Design
Authors: Yang S. M. , Sheu G. J. , Yang C. D.
Published: March 2021

This paper presents a controller design methodology for vibration suppression of rotor systems in noncollocated sensor/actuator configuration. The methodology combines the experimental design method of quality engineering and the active damping control technique such that their advantages in implementation feasibility and performance-robustness can be integrated together. Compared with LQ-based design, the controller order is smaller and it is applicable to systems in an operation speed range. In addition, neither preselected sensor/actuator location nor state measurement/estimation is needed. By using the locations of sensor/actuator and the feedback gains as design parameters, the controller is shown to achieve the best possible system performance while maintaining the closed loop system stability. Analyses also show that, contrary to common believe, the performance of a closed loop system with noncollocated sensor/actuator can be superior to that with a collocated one.
Application of Harmonic Shape Function in Finite Element Modal Analysis
Authors: Surampudi R. , Gupta A.
Published: March 2021

Existing element types available in finite element codes typically utilize polynomial shape functions to define the displacement field in the problem of interest. The polynomial shape functions serve the purpose adequately in static analysis where the displacements and the stresses in a structure are of primary interest. These shape functions give rise to increasing inaccuracy for higher natural frequencies. It is shown that harmonic shape functions yield better results for the higher natural frequencies with same element count. Axial vibrations of bars and transverse vibrations of beams have been analyzed using harmonic shape functions. A comparative analysis has been made between results predicted by the harmonic interpolation functions and polynomial interpolation functions using same number of nodes.
Flexural Vibration of Turbine Generator Rotors: Application of Modal Analysis to Predictions of the Effects of Light Rubs
Authors: Wilkinson Terence S.
Published: March 2021

Methods for calculating the effects of periodic contact between the stators and rotors of large turbine generator systems are discussed. The case of periodic contact between a stator and part of the LP turbine rotor of a modern turbine generator is selected for study. The rotor is part of a train which includes, in order, HP, IP, and (one) LP turbines, each supported by two journal bearings solidly coupled to each other and to an alternator which is supported by three bearings, one of which carries little load and is popularly known as a steady bearing. The periodic contact is supposed to be caused by poor alignment of the rotor relative to the stator and by vibration of the rotor due to unbalance. Comparisons are made between the effects predicted using modal analysis, using models of the LP turbine rotor of Jeffcott type (Wilkinson, 1987), and those obtained using more accurate methods. It is assumed that the normal forces generated during contact are proportional to the interference between rotor and stator and that the tangential force can be calculated with sufficient accuracy by using a coefficient of friction. It is shown that light rubs usually causes periodic synchronous responses but subharmonics may also appear. There is little doubt that chaotic vibration will ensue if rubs become heavier than those considered.

It is suggested mat modal analysis methods are probably best for long rotor systems, however, the simplest models reveal the correct qualitative behaviour.

The work forms part of a wider investigation of the effects of rotor/stator interaction and at the time of writing a test rig is being manufactured to facilitate the measurement of response to unbalance, the effects of misalignment and the response to light rubs. Aspects of the design of the six bearing rig, which is claimed to be a true scale model of a substantial fragment of the nine bearing turbine generator rotor system discussed earlier, are also described.
Calculated Rotordynamic Behaviour of a Twin Spool Engine and the Comparison With Test Results
Authors: Domes B. , Hartmüller H. , Tokar G. , Wang G.
Published: March 2021

The new BR 700 series of twin spool engines, of the thrust class of 15,000 to 20,000 pounds, is being developed for business jets. In this paper the rotordynamic vibration analysis is performed with a detailed whole engine model including both rotors, bearings with oil squeeze film dampers and squirrel cages, the engine structure, the mounts and the fuselage. The analytical method is described and some calculated results are presented. The effectiveness of the oil squeeze film dampers on all main bearings will be demonstrated. The comparison of the analytical and the measured results gives a good agreement in the resonance frequencies and in the damping characteristics. It also shows that a linear analysis can describe with sufficient accuracy the dynamic behaviour of such a complex structure like a twin spool engine under normal operating conditions.
Forced and Natural Vibration Analysis of Mistuned Practical Turbomachine Impellers Using Multifreedom Models
Authors: Petrov Evgueni P.
Published: March 2021

A computational technique is suggested to calculate forced and natural vibrations of axial flow turbomachine impellers having any kind of distortions of blading symmetry: as caused by blades’ mistuning due to inaccuracies of blade geometry within manufacturing tolerances and as caused by special design of blade connections by shrouds or wires. The impellers with flexible and stiff disk are examined. Multifreedom models are used for analysis. Peculiarities of excitation due to inhomogeneous aerodynamic loadings or rotor vibrations as well as damping in material, aerodamping are taken into account.
Passenger Ride Comfort Through Observer Based Control
Authors: Taghirad H. D. , Esmailzadeh E.
Published: March 2021

An analytical investigation of a half-car model including passenger dynamics, subjected to random road disturbances is performed, and the advantage of active over conventional passive suspension systems are examined. Two different performance indices for optimal controller design are proposed. The performance index is a quantification of both ride comfort and road handling. Due to practical limitations, all the states required for the state-feedback controller are not measurable, and thus must be estimated with an observer. Stochastic inputs are applied to simulate realistic road surface conditions, and statistical comparisons between passive system and the two controllers, with and without state estimator, are carried out to gain a clearer insight into the performance of the controllers. The simulation results demonstrate that an optimal observer-based controller, when including passenger acceleration in the performance index, retains both excellent ride comfort and road handling characteristics.
Rigid and Flexible Body Modeling for a Triaxial Shaker Control System
Authors: Dougherty John J. , El-Sherief Hossny , Nguyen Thanh
Published: March 2021

The modeling of a triaxial shaker system is discussed. The shaker system has eight inputs and six outputs. The models have been implemented in a computer simulation; both the rigid body and flexible body effects have been simulated. Results from the simulation have been compared to test data.
Dynamic Walk of a Quadruped Locomotion Robot Using Robust Optimal Tracking Control
Authors: Uchida Hiroaki , Nonami Kenzo
Published: March 2021

We propose a new control system design strategy that is called “frequency-shaped optimal tracking control method” in this paper. We make sure that the proposed method is very useful by creating the quasi-dynamic walk of a quadruped locomotion robot. During control of the locomotion robot, high feedback (FB) gains should be selected to work against the force and the moment from the body and the reaction force from the ground. However, if high FB gains are used, high frequency vibration comes out because of the backlash of the gear. Frequency-shaped optimal control is the control method to improve the robustness against the disturbance like high frequency vibration. Frequency-shaped optimal tracking control extends the frequency-shaped optimal control to the servo system like the trajectory following control of the robot. First, we’ll show the design scheme of the frequency-shaped optimal tracking control. Next, we’ll show how decentralized control is realized in order to apply frequency-shaped optimal tracking control. Finally, we’ll compare the frequency-shaped optimal tracking control with the optimal tracking control from the points of view of the simulations and the experiments.
Magnetically Induced Vibration in an 8-Pole, 9-Slot Brushless DC Motor
Authors: Chuang Thomas Y. , Lieu Dennis K.
Published: March 2021

A parametric study was conducted to determine the effect of motor geometry on the force imbalance in an 8-pole/9-slot motor. The study is based on a quasi-static finite element analysis in which the force calculations were made by integrating the Maxwell stresses along the center of the airgap. For small variations from the base motor geometry, the study revealed the following trends. The magnitude of the force imbalance decreases as the slot width decreases. The imbalance also decreases as the airgap length increases. A rotor/stator eccentricity introduces a constant force imbalance which increases proportionally to, and in the direction of, the eccentricity. As the size of the motor is scaled up uniformly, the mass increases faster than the imbalance. The results suggest that the force imbalance is caused predominantly by the stress concentrations at the corners of the stator teeth.
Optimal Length of Constrained Layers on a Substrate With Linearly Varying Strain
Authors: Demoret Kimberly B. , Torvik Peter J.
Published: March 2021

The performance of a constrained layer damping treatment is greatly affected by its length, and the damping effectiveness can be optimized by choosing a damping treatment length appropriate to the geometry and material properties of the viscoelastic and constraining layers. In this paper, the equilibrium equation and boundary conditions are formulated for a constraining layer on a substrate with a linearly varying strain distribution, and an analysis is developed that allows conclusions to be drawn about the optimal length of the constraining layer. Plunkett and Lee1 analyzed this problem for the special case of uniform strain in the substrate, and they showed that a loss coefficient depends only on the viscoelastic loss factor and a stiffness parameter that is a function of the material properties and thickness of the damping layers. In this paper, the uniform strain analysis is extended for the case of linearly varying substrate strain of the form ax+b, where a and b are arbitrary constants. The corresponding loss coefficient was shown to be a function of the parameters identified in the uniform strain problem, plus an additional parameter that accounts for the degree of non-uniformity of the substrate strain. It is shown that the non-uniformity of the substrate strain increases the length at which the damping treatment is optimized.
Optimal Damping of Vibrations in Multibody Systems Through Equivalent Friction Control Laws
Authors: Dakev Nikolay V. , Chipperfield Andrew J. , Fleming Peter J.
Published: March 2021

In the paper modelling and optimization of friction laws and energy exchange processes in multibody systems are considered. The multibody systems are regarded as chains of absolutely rigid bodies with compliance and friction concentrated at the connections. It is proposed to control the vibration level of such systems by introducing equivalent frictional forces. Such an approach enables modelling and optimization of passive and semi-active damping methods together with active control of vibrations in multibody systems within a unified framework. In particular, the equivalent friction laws can be regarded as controls minimizing deviations of the multibody system motion from the reference trajectory and used for total compensation of links cross interactions and stabilization of fast modes.

The corresponding optimal vibration control problem is formulated and reduced to a constrained optimization one in order to determine the optimal friction laws dissipating the oscillation energy. For linear vibration control problems numerical methods based on solving matrix Lyapunov and Riccati equations are discussed. Additionally, an approach employing a global search mechanism, the genetic algorithm, and parallel processing techniques, to alleviate the problem of computational burden, is proposed to solve general control problems for optimal vibration damping.

Two examples are presented in order to illustrate the proposed approach.
Experimental Identification of Structural Damage by Neural Networks
Authors: Ceravolo Rosario , De Stefano Alessandro , Grosjacques Michel , Sabia Donato
Published: March 2021

The problems involved in structural damage identification by means of pattern recognition neural techniques are addressed. As is known, mechanical system recognition can be achieved by making appropriate use of these connectionistic instruments. Recognition takes place on the basis of an incomplete set of data contained in the system’s dynamic response.

Some methods, previously developed by the authors on the basis of numerical models, are validated through the use of noisy data. To this end, an experimental research was carried out on simply supported beams. The tests made it possible to acquire a wealth of dynamic response data from beams damaged artificially to produce defects of varying entity and position. The data obtained, appropriately normalised, are used as inputs for supervised neural networks. In particular, frequency analysis data are able to provide a summary characterisation of the distortion in a structure’s dynamic behaviour.

Different signal processing and analysis procedures are compared in order to identify the best resolution and sensitivity capabilities in the diagnostic performance of neural networks.
Application of a Model Updating Technique for Health Condition Monitoring and Damage Detection of Flexible Structures
Authors: Pereira Joao A. , Heylen Ward , Lammens Stefan , Sas Paul
Published: March 2021

This paper discusses the application of a damage detection methodology to monitor the location and extent of partial structural damage. The methodology combines, in an iterative way, the model updating technique based on frequency response functions (FRF) with monitoring data aiming at identifying the damage area of the structure. After the updating procedure reaches a good correlation between the models, it compares the parameters of the damage structure with those of the undamaged one to find the deteriorated area. The influence of the FEM mesh size on the evaluation of the extent of the damage has also been discussed. The methodology is applied using real experimental data from a spatial frame structure.
Intensified Training Supersedes the Impact of Heat and/or Altitude for Increasing Performance in Elite Rugby Union Players
Authors: Racinais Sebastien , Périard Julien D. , Piscione Julien , Bourdon Pitre C. , Cocking Scott , Ihsan Mohammed , Lacome Mathieu , Nichols David , Townsend Nathan , Travers Gavin , Wilson Mathew G. , Girard Olivier
Published: March 2021

Purpose: To investigate whether including heat and altitude exposures during an elite team-sport training camp induces similar or greater performance benefits. Methods: The study assessed 56 elite male rugby players for maximal oxygen uptake, repeated-sprint cycling, and Yo-Yo intermittent recovery level 2 (Yo-Yo) before and after a 2-week training camp, which included 5 endurance and 5 repeated-sprint cycling sessions in addition to daily rugby training. Players were separated into 4 groups: (1) control (all sessions in temperate conditions at sea level), (2) heat training (endurance sessions in the heat), (3) altitude (repeated-sprint sessions and sleeping in hypoxia), and (4) combined heat and altitude (endurance in the heat, repeated sprints, and sleeping in hypoxia). Results: Training increased maximal oxygen uptake (4% [10%], P = .017), maximal aerobic power (9% [8%], P < .001), and repeated-sprint peak (5% [10%], P = .004) and average power (12% [14%], P < .001) independent of training conditions. Yo-Yo distance increased (16% [17%], P < .001) but not in the altitude group (P = .562). Training in heat lowered core temperature and increased sweat rate during a heat-response test (P < .05). Conclusion: A 2-week intensified training camp improved maximal oxygen uptake, repeated-sprint ability, and aerobic performance in elite rugby players. Adding heat and/or altitude did not further enhance physical performance, and altitude appears to have been detrimental to improving Yo-Yo.
Parallel molecular mechanisms for enzyme temperature adaptation
Authors: Pinney Margaux M. , Mokhtari Daniel A. , Akiva Eyal , Yabukarski Filip , Sanchez David M. , Liang Ruibin , Doukov Tzanko , Martinez Todd J. , Babbitt Patricia C. , Herschlag Daniel
Published: March 2021

Some like it hot, others not

Enzymes strike a delicate balance between features that enhance chemical reactivity and those that contribute to stable structure. Both features are important and can be unrelated or antagonistic. Pinneyet al.combined rich experimental work on thermophilic and mesophilic variants of the enzyme ketosteroid isomerase (KSI) with bioinformatic data from a diverse set of bacterial enzymes to reveal the molecular determinants of thermal adaptation in enzymes. For KSI, they observed a trade-off between activity and thermal stability that comes down to a single active-site residue. With their larger dataset, they identified patterns of individual amino acid substitutions that are favored at higher temperatures, and also consider how networks of stabilizing interactions develop.

Science, this issue p.eaay2784
Infectious diseases and social distancing in nature
Authors: Stockmaier Sebastian , Stroeymeyt Nathalie , Shattuck Eric C. , Hawley Dana M. , Meyers Lauren Ancel , Bolnick Daniel I.
Published: March 2021

Nature's “responsible” response to disease

With the emergence of the COVID-19 pandemic, there have been global calls for the implementation of “social distancing” to control transmission. Throughout the world, some have resisted this requirement with the unfounded argument that it is unnecessary or ineffective. Social distancing, however, is a natural consequence of disease across animals, both human and nonhuman. Stockmaier
et al.
reviewed responses to disease across animal taxa and reveal how these responses naturally limit disease transmission. Understanding such natural responses and their impacts on pathogenic transmission provides epidemiological insight into our own responses to pandemic challenges.

Science
, this issue p.
eabc8881
A nearby transiting rocky exoplanet that is suitable for atmospheric investigation
Authors: Trifonov T. , Caballero J. A. , Morales J. C. , Seifahrt A. , Ribas I. , Reiners A. , Bean J. L. , Luque R. , Parviainen H. , Pallé E. , Stock S. , Zechmeister M. , Amado P. J. , Anglada-Escudé G. , Azzaro M. , Barclay T. , Béjar V. J. S. , Bluhm P. , Casasayas-Barris N. , Cifuentes C. , Collins K. A. , Collins K. I. , Cortés-Contreras M. , de Leon J. , Dreizler S. , Dressing C. D. , Esparza-Borges E. , Espinoza N. , Fausnaugh M. , Fukui A. , Hatzes A. P. , Hellier C. , Henning Th. , Henze C. E. , Herrero E. , Jeffers S. V. , Jenkins J. M. , Jensen E. L. N. , Kaminski A. , Kasper D. , Kossakowski D. , Kürster M. , Lafarga M. , Latham D. W. , Mann A. W. , Molaverdikhani K. , Montes D. , Montet B. T. , Murgas F. , Narita N. , Oshagh M. , Passegger V. M. , Pollacco D. , Quinn S. N. , Quirrenbach A. , Ricker G. R. , Rodríguez López C. , Sanz-Forcada J. , Schwarz R. P. , Schweitzer A. , Seager S. , Shporer A. , Stangret M. , Stürmer J. , Tan T. G. , Tenenbaum P. , Twicken J. D. , Vanderspek R. , Winn J. N.
Published: March 2021

A transiting rocky planet 8 parsecs away

Most exoplanets have been detected using either the radial velocity (RV) method or the transit method, which provide only limited information on the planet's physical properties. In the rare cases in which both methods detect the same planet, the combination determines the planet's mass, radius, and density. Trifonov
et al.
identified a planet, Gliese 486 b, using both RV and transit data. The host star is a red dwarf only 8 parsecs away, making this one of the closest exoplanet systems known. A rocky super-Earth, Gliese 486 b has an equilibrium surface temperature of 700 kelvin. The authors say that it is observationally favorable for searches for an atmosphere.

Science
, this issue p.
1038
Linear System of Differential Equations with a Quadratic Invariant as the Schrödinger Equation
Authors: Kozlov V. V.
Published: March 2021

Linear systems of differential equations with an invariant in the form of a positive definite quadratic form in a real Hilbert space are considered. It is assumed that the system has a simple spectrum and the eigenvectors form a complete orthonormal system. Under these assumptions, the linear system can be represented in the form of the Schrödinger equation by introducing a suitable complex structure. As an example, we present such a representation for the Maxwell equations without currents. In view of these observations, the dynamics defined by some linear partial differential equations can be treated in terms of the basic principles and methods of quantum mechanics.
Patients’ participation in government-sponsored guidelines in Latin America: a cross-sectional study
Authors: Garegnani Luis Ignacio , Meza Nicolás , Rosón-Rodriguez Pablo , Escobar-Liquitay Camila Micaela , Arancibia Marcelo , Madrid Eva , Franco Juan Victor Ariel
Published: March 2021

Background

It is recommended that patients actively participate in clinical practice guideline (CPG) development, which allows consideration of their values and preferences and improves adherence to recommendations. The development of CPGs throughout Latin America is variable and diverse, and the inclusion of patients’ participation is unknown.

Objectives

To evaluate the methods of patients’ participation in government-sponsored CPGs in Latin America, the type of CPG development and the use of Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methods.

Design

Cross-sectional study. We included CPGs developed over the last 10 years through a comprehensive hand search in official national government websites and biomedical databases.

Main outcome measure

The type of patients’ participation was coded according to five predefined categories. We also report the proportion of application of GRADE methods.

Results

We included 408 CPGs from 10 countries: 74% (n=303) were de novo development, 13%(n=55) used an adaptation method and 10%(n=41) used both adaptation and de novo methods. Only 45% (n=185) applied the GRADE approach, ranging from 14% (n=12) of CPGs in Brazil to 89% (n=56) of CPGs in Colombia. Only 23% (n=95) of CPGs included at least one method of patients’ participation. Mexico was one of the largest CPG producers (100 CPGs), but none included methods of patients’ participation; in turn, in countries with lower production of government-sponsored CPGs, patients’ participation was found in almost 88%. Guidelines using the GRADE approach were more likely to use methods of patients’ participation. These methods were highly variable: 46% (n=44) incorporated patients in the panel, 81% (n=77) searched for evidence about patients’ values and preferences, 43% (n=39) used an external review of the draft recommendations by patients, 38% (n=36) used public comments, and 2% included other methods for stakeholders’ participation.

Conclusion

Only one quarter of government-sponsored CPGs in the Latin American region incorporated a method for patients’ participation, which varied considerably across the selected countries. These findings highlight the need to improve CPG development methods to systematically incorporate patients’ values and preferences when drafting recommendations.
Testing and implementing video consulting for outpatient appointments: using quality improvement system thinking and codesign principles
Authors: Morrison Clare , Beattie Michelle , Wherton Joseph , Stark Cameron , Anderson Julie , Hunter-Rowe Carolyn , Gray Nicola M
Published: March 2021

Increasing demand for outpatient appointments (OPA) is a global challenge for healthcare providers. Non-attendance rates are high, not least because of the challenges of attending hospital OPAs due to transport difficulties, cost, poor health, caring and work responsibilities. Digital solutions may help ameliorate these challenges. This project aimed to implement codesigned outpatient video consultations across National Health Service (NHS) Highland using system-wide quality improvement approaches to implementation, involving patients, carers, clinical and non-clinical staff, national and local strategic leads. System mapping; an intensive codesign process involving extensive stakeholder engagement and real-time testing; Plan, Do, Study, Act cycles; and collection of clinician and patient feedback were used to optimise the service. Standardised processes were developed and implemented, which made video consulting easy to use for patients, embedded video into routine health service systems for clinicians and non-clinical staff, and automated much of the administrative burden. All clinicians and staff are using the system and both groups identified benefits in terms of travel time and costs saved. Transferable lessons for other services are identified, providing a practical blueprint for others to adapt and use in their own contexts to help implement and sustain video consultation services now and in the future.
Validation of ICD-10-CM codes for injuries complicating pregnancy, childbirth and the puerperium: a medical record review
Authors: Hansen Anna , Quesinberry Dana , Akpunonu Peter , Martin Julia , Slavova Svetla
Published: March 2021

Introduction

The purpose of this study was to estimate the positive predictive value (PPV) of International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) codes for injury, poisoning, physical or sexual assault complicating pregnancy, childbirth and the puerperium (PCP) to capture injury encounters within both hospital and emergency department claims data.

Methods

A medical record review was conducted on a sample (n=157) of inpatient and emergency department claims from one Kentucky healthcare system from 2015 to 2017, with any diagnosis in the ICD-10-CM range O9A.2-O9A.4. Study clinicians reviewed medical records for the sampled cases and used an abstraction form to collect information on documented presence of injury and PCP complications. The study estimated the PPVs and the 95% CIs of O9A.2-O9A.4 codes for (1) capturing injuries and (2) capturing injuries complicating PCP.

Results

The estimated PPV for the codes O9A.2-O9A.4 to identify injury in the full sample was 79.6% (95% CI 73.3% to 85.9%) and the PPV for capturing injuries complicating PCP was 72.0% (95% CI 65.0% to 79.0%). The estimated PPV for an inpatient principal diagnosis O9A.2-O9A.4 to capture injuries was 90.7% (95% CI 82.0% to 99.4%) and the PPV for capturing injuries complicating PCP was 88.4% (95% CI 78.4% to 98.4%). The estimated PPV for any mention of O9A.2-O9A.4 in emergency department data to capture injuries was 95.2% (95% CI 90.6% to 99.9%) and the PPV for capturing injuries complicating PCP was 81.0% (95% CI 72.4% to 89.5%).

Discussion

The O9A.2-O9A.4 codes captured high percentage true injury cases among pregnant and puerperal women.
Exploring the implications of the new ICD-10-CM classification system for injury surveillance: analysis of dually coded data from two medical centres
Authors: Poltavskiy Eduard A , Fenton Susan H , Atolagbe Oluseun , Sadeghi Banafsheh , Bang Heejung , Romano Patrick S
Published: March 2021

Introduction

External cause of injury matrices is used to classify mechanisms/causes of injuries for surveillance and research. Little is known about the performance of the Centers for Disease Control and Prevention’s new external cause of injury matrix for Clinical Modification of the 10th Revision of the International Classification of Diseases (ICD-10-CM), compared with the ICD-9-CM version.

Methods

Dually coded (ICD-9-CM and ICD-10-CM) administrative data were obtained from two major academic trauma centres. Injury-related cases were identified and categorised by mechanism/cause and manner/intent. Comparability ratios (CR) were used to estimate the net impact of changing from ICD-9-CM to ICD-10-CM on the number of cases classified to each mechanism/cause category. Chamberlain’s percent positive agreements (PPA) were calculated and McNemar’s test was used to assess the significance of observed classification differences.

Results

Of 4832 and 5211 dual-coded records from the two centres, 632 and 520 with injury-related principal diagnoses and external cause codes in both ICD-9-CM and ICD-10-CM were identified. CRs for the mechanisms/causes with at least 20 records ranged from 0.85 to 1.9 at one centre and from 0.97 to 1.07 at the other. Among these mechanisms/causes, PPAs ranged from 33% for ‘other transport’ to 94% for poisoning at one centre, and from 75% for ‘other transport’ to 100% for fires/burns at the other centre. Case assignment differed significantly for falls, motor vehicle traffic, other transport, and ‘struck by/against’ injuries at one centre, and for ‘other pedal cyclist’ at the other centre.

Conclusion

Switching to ICD-10-CM and the new external cause of injury matrix may affect injury surveillance and research, especially for certain mechanisms/causes.
Trends in inequalities in disability in Europe between 2002 and 2017
Authors: Rubio Valverde Jose R , Mackenbach Johan P , Nusselder Wilma J
Published: March 2021

Background

Monitoring socioeconomic inequalities in population health is important in order to reduce them. We aim to determine if educational inequalities in Global Activity Limitation Indicator (GALI) disability have changed between 2002 and 2017 in Europe (26 countries).

Methods

We used logistic regression to quantify the annual change in disability prevalence by education, as well as the annual change in prevalence difference and ratio, both for the pooled sample and each country, as reported in the European Union Statistics on Income and Living Conditions (EU-SILC) and the European Social Survey (ESS) for individuals aged 30–79 years.

Results

In EU-SILC, disability prevalence tended to decrease among the high educated. As a result, both the prevalence difference and the prevalence ratio between the low and high educated increased over time. There were no discernible trends in the ESS. However, there was substantial heterogeneity between countries in the magnitude and direction of these changes, but without clear geographical patterns and without consistency between surveys.

Conclusions

Socioeconomic inequalities in disability appear to have increased over time in Europe between 2002 and 2017 as per EU-SILC, and have persisted as measured by the ESS. Efforts to further harmonise disability instruments in international surveys are important, and so are studies to better understand international differences in disability trends and inequalities.
Spectroscopic study of EUV and SXR spectral lines with partition function and level population of W LVI
Authors: Sharma Rinku , Richa Paijwar
Published: March 2021

We present a comprehensive and elaborate study of W LVI (K-like W55+) by using multi-configuration Dirac–Fock method (MCDF). We have included relativistic corrections, QED (quantum electrodynamics) and Breit corrections in our computation. We have reported energy levels and radiative data for multipole transitions (i.e., electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2)) within the lowest 142 fine-structure levels and predicted soft X-ray transition (SXR) and extreme ultraviolet transitions (EUV) from higher excited states to the ground state. We have compared our calculated data with energy levels compiled by NIST and other available results in the literature and the small discrepancies found with them are discussed. Because only a few of the lowest levels are available in the literature, for checking excitation energies of higher excited states we have performed the same calculations with the distorted wave method. Furthermore, we have also provided relative population for the first five excited states, with both the partition function and thermodynamic quantities for W LVI and studied their variations with temperature. We believe that our reported new atomic data of W LVI may be useful in identification and analysis of spectral lines from various astrophysical and fusion plasma sources and may also be beneficial in plasma modeling.
Survey on Periodic Scheduling for Time-triggered Hard Real-time Systems
Authors: Minaeva Anna , Hanzálek Zdeněk
Published: March 2021

This survey covers the basic principles and related works addressing the time-triggered scheduling of periodic tasks with deadlines. The wide range of applications and the increasing complexity of modern real-time systems result in the continually growing interest in this topic. However, the articles in this field appear without systematic notation. To address it, we extend the three-field Graham notation to cover periodic scheduling. Moreover, we formally define three example periodic scheduling problems (PSPs) and provide straightforward implementations of these examples in the Satisfiability Modulo Theories formalism with source codes. Then, we present a summary of the complexity results containing existing polynomially solvable PSPs. We also provide an overview of simple state-of-the-art methods and tricks to solve the PSPs efficiently in terms of time. Next, we survey the existing works on PSP according to the resource environment: scheduling on a single resource, on parallel identical resources, and on dedicated resources. In the survey, we indicate which works propose solution methods for more general PSPs. Finally, we present related problems that are not periodic by nature to provide inspiration for the PSP solution.
Fine particulate matter (PM2.5) inhalation-induced alterations in the plasma lipidome as promoters of vascular inflammation and insulin resistance
Authors: Hill Bradford G. , Rood Benjamin , Ribble Amanda , Haberzettl Petra
Published: March 2021

We found that circulating plasma constituents are responsible for air pollution-induced vascular pathologies. Inhalation of fine particulate matter (≤PM2.5) promotes a unique form of dyslipidemia that manifests in a manner dependent upon pulmonary oxidative stress. The air pollution-engendered dyslipidemic phenotype is characterized by elevated free fatty acid species and diminished phospholipid species, which could contribute to vascular inflammation and loss of insulin sensitivity.
Extracellular vesicle interplay in cardiovascular pathophysiology
Authors: Saheera Sherin , Jani Vivek P. , Witwer Kenneth W. , Kutty Shelby
Published: March 2021

Extracellular vesicles (EVs) are nanosized lipid bilayer-delimited particles released from cells that mediate intercellular communications and play a pivotal role in various physiological and pathological processes. Subtypes of EVs may include plasma membrane ectosomes or microvesicles and endosomal origin exosomes, although functional distinctions remain unclear. EVs carry cargo proteins, nucleic acids (RNA and DNA), lipids, and metabolites. By presenting or transferring this cargo to recipient cells, EVs can trigger cellular responses. We summarize contemporary understanding of EV biogenesis, composition, and function, with an emphasis on the role of EVs in the cardiovascular system. In addition, we outline the functional relevance of EVs in cardiovascular pathophysiology, further highlighting their potential for diagnostic and therapeutic applications.
Benchmark Pashto Handwritten Character Dataset and Pashto Object Character Recognition (OCR) Using Deep Neural Network with Rule Activation Function
Authors: Uddin Imran , Ramli Dzati A. , Khan Abdullah , Bangash Javed Iqbal , Fayyaz Nosheen , Khan Asfandyar , Kundi Mahwish
Published: March 2021

In the area of machine learning, different techniques are used to train machines and perform different tasks like computer vision, data analysis, natural language processing, and speech recognition. Computer vision is one of the main branches where machine learning and deep learning techniques are being applied. Optical character recognition (OCR) is the ability of a machine to recognize the character of a language. Pashto is one of the most ancient and historical languages of the world, spoken in Afghanistan and Pakistan. OCR application has been developed for various cursive languages like Urdu, Chinese, and Japanese, but very little work is done for the recognition of the Pashto language. When it comes to handwritten character recognition, it becomes more difficult for OCR to recognize the characters as every handwritten character’s shape is influenced by the writer’s hand motion dynamics. The reason for the lack of research in Pashto handwritten character data as compared to other languages is because there is no benchmark dataset available for experimental purposes. This study focuses on the creation of such a dataset, and then for the evaluation purpose, a machine is trained to correctly recognize unseen Pashto handwritten characters. To achieve this objective, a dataset of 43000 images was created. Three Feed Forward Neural Network models with backpropagation algorithm using different Rectified Linear Unit (ReLU) layer configurations (Model 1 with 1‐ReLU Layer, Model 2 with 2‐ReLU layers, and Model 3 with 3‐ReLU Layers) were trained and tested with this dataset. The simulation shows that Model 1 achieved accuracy up to 87.6% on unseen data while Model 2 achieved an accuracy of 81.60% and 3% accuracy, respectively. Similarly, loss (cross‐entropy) was the lowest for Model 1 with 0.15 and 3.17 for training and testing, followed by Model 2 with 0.7 and 4.2 for training and testing, while Model 3 was the last with loss values of 6.4 and 3.69. The precision, recall, and f‐measure values of Model 1 were better than those of both Model 2 and Model 3. Based on results, Model 1 (with 1 ReLU activation layer) is found to be the most efficient as compared to the other two models in terms of accuracy to recognize Pashto handwritten characters.
Extraction of Flavonoids from Corn Silk and Biological Activities In Vitro
Authors: Tian Shuangqi , Sun Yue , Chen Zhicheng
Published: March 2021

When harvesting corn, corn silk was discarded as waste, including the compounds isolated and identified from corn silk such as flavonoids, sterols, alkaloids, polysaccharides, organic acids, volatile oils, trace elements, and multivitamins. It not only pollutes the environment but also wastes resources. In this paper, extraction methods commonly used for extracting flavonoids from corn silk were reviewed, such as reagent method, enzymatic method, microwave, supercritical CO2 extraction, ultrasonic, and microwave-assisted ultrasonic. Flavonoids are natural antioxidants and have application value in scavenging free radicals, inhibiting bacteria, and regulating blood lipids. The in vitro biological activities of flavonoids from corn silk extracted by different extraction methods were also compared.
Allocating active power loss with network reconfiguration in electrical power distribution systems
Authors: Hota Ambika Prasad , Mishra Sivkumar , Mishra Debani Prasad , Salkuti Surender Reddy
Published: March 2021

This paper presents a branch exchange (BE) based heuristic network reconfiguration technique where, the proposed bus classification strategy remodels dynamically as per the modified topology in order to provide a reconfigured network with minimum loss. Further, for fair allocation of the active power losses, it develops a new active power loss allocation (APLA) technique which eradicates the influence of cross-term analytically from loss formulation without any assumptions and approximations. The effectiveness of the proposed procedure has been investigated against other established methods using a 69-bus radial distribution network (RDN). The results of APLA achieved for original and reconfigured 69-bus RDN are found to be promising and judicious as regard to their load demands and geographical locations. The implementation of present reconfiguration procedure provides a total loss reduction benefit of 55.73% to the utility which highlights the significance of the developed procedure against other established techniques.
Impact of the hybrid reactive power compensator on the power grid used a fuzzy PI regulator
Authors: Rahmouni Abdelkader
Published: March 2021

The work presented in this article is a contribution to the problem of controlling reactive powers and voltages in an electrical network. Among these control tools, the static reactive power compensator (SVC) was chosen because of its simplicity of control. SVC is one of the Alternative Flexible Current Transmission Systems (FACTS) devices which help to solve the problems encountered in the operation of electrical networks, either on the distribution side or on the transport side. To increase its compensation efficiency in the face of harmonic currents which cause voltage distortion, we have introduced a three-phase harmonic filter. This new hybrid SVC is used to control the reactive power, the voltage and in addition to reduce the voltage distortion and the correction of the power factor in the electrical energy transport network. In order to improve its efficiency, two voltage regulation systems have been chosen in the control system for this compensator, the fuzzy PI regulator and the PIP regulator.
Reactive power sharing among distributed generators in a microgrid by using virtual current
Authors: Molina-Viloria Eder A. , Becerra John Edwin Candelo , Velasco Fredy Edimer Hoyos
Published: March 2021

This paper presents a new autonomous effective power distribution control strategy for three-phase parallel inverters. The proposal uses a controller that can provide the system with accurate power sharing among distributed generators installed in the microgrid once some load variations are presented in the network. The methodology uses a virtual current loop introduced into the current controller of the inverter to optimize the output signal, which goes directly to the PWM. This virtual current is obtained by using a virtual impedance loop. Furthermore, a small-signal model of the system is used to check stability of the proposed control strategy, which was developed for island mode operation of the microgrid. Simulations were performed for a microgrid with two generators and a load with five households and implemented in MATLAB/Simulink software. The results show that the model provides a wide margin of stability and a rapid response when electrical loads change, thus fulfilling the reactive power sharing among generators. The proposed method shows a large margin of stability and a rapid transient response of the system.
Derivation of a Coronary Age Calculator Using Traditional Risk Factors and Coronary Artery Calcium: The Multi‐Ethnic Study of Atherosclerosis
Authors: Blaha Michael J. , Naazie Isaac N. , Cainzos‐Achirica Miguel , Dardari Zeina A. , DeFilippis Andrew P. , McClelland Robyn L. , Mirbolouk Mohammadhassan , Orimoloye Olusola A. , Dzaye Omar , Nasir Khurram , Page John H.
Published: March 2021

Background

The optimal method for communicating coronary heart disease (CHD) risk to individual patients is not yet clear. Recent research supports the concept of "coronary age" for more effective risk communication. We defined an individual's coronary age as the age at which an average healthy individual would have an equivalent estimated CHD risk as that calculated for the index individual, building on our previously validated MESA (Multi‐Ethnic Study of Atherosclerosis) 10‐year CHD Risk Score equations with and without coronary artery calcium (CAC).

Methods and Results

We derived a coronary age by (1) calculating the MESA 10‐year CHD risk; (2) mathematically setting this equal to an equation describing risk of an average healthy MESA participant, as a function of age; and (3) solving for age. The risk discrimination of the resultant coronary age was compared with that of chronological age, the MESA CHD Risk Score, and CAC alone. Approximately 95% of coronary age values ranged from 30 years less to 30 years higher than chronological age. Although the mean chronological age of individuals experiencing CHD events compared with those free of events was 67.4 versus 61.8 years, the difference in coronary age including CAC was larger (80.6 versus 62.8 years). Coronary age with CAC had identical predictive ability to that of MESA CHD Risk Score and outperformed chronological age and CAC alone.

Conclusions

The newly derived coronary age is a convenient transformation of MESA CHD Risk, retaining very good risk discrimination. This easy‐to‐communicate tool will be available for patients and clinicians, potentially facilitating risk communication in routine care.