bluuebunny/crossref_metadata_2025 huggingface dataset:
The Development of High-Output Free-Piston Gas Generators
Authors: Lasley R. A. , Lewis F. M.
Published: July 2022

The development of free-piston gas generators suitable for naval-propulsion purposes was started in 1943 at the Baldwin-Lima-Hamilton Corporation, then the General Machinery Corporation, under a contract with the U. S. Navy Department. At that time little was known in this country regarding the free-piston developments of Pescara in France or Sulzer in Switzerland, which had already been under way for some years. This paper traces the progress made in this project and describes the construction and operating characteristics of various models which have been made during the course of the program.
An Analytical Approach to the Design of Four-Link Mechanisms
Authors: Freudenstein Ferdinand
Published: July 2022

The symmetry inherent in four-link mechanisms has been used in deriving a general analytical expression relating the diagonals of a four-link mechanism by means of a characteristic parameter. The nature of this expression has been analyzed. The particular case obtained by using as a parameter the square root of the sum of the squares of the lengths of the links diminished by the sum of the squares of the diagonals, has been worked out in detail and the results reduced to a form believed to be useful in design work. Design applications have been considered.
Minimization of Gear-Train Inertia
Authors: Burgess E. G.
Published: July 2022

In the design of a system consisting of a motor driving an inertial load through gearing it is often necessary that the acceleration of the load be a maximum. The gear ratios giving a maximum acceleration are determined here either for a specified over-all train ratio, or for the condition where the over-all ratio must be found. Charts, which embody certain simplifying assumptions, are provided for selecting the optimum number of gear ratios and the ratios of the individual meshes corresponding to maximum load acceleration.
Effect of Single Roughness Elements on the Heat Transfer From a 1:3 Elliptical Cylinder
Authors: Seban R. A. , Levy S. , Doughty D. L. , Drake R. M.
Published: July 2022

The effect of single roughness elements on the heat transfer from the surface of a 1:3 elliptical cylinder to an air stream has been investigated by placing single spanwise nylon filaments on the surface of the cylinder. The results are compared with those for the smooth surface of the same cylinder which have already been presented and, as before, these results are given in terms of the pressure coefficient, recovery factor, and local heat-transfer coefficient. On-stream air speeds ranged from 184 to 423 fps giving Reynolds numbers, based on the 6-in. chord of the cylinder, from 531,000 to 1,200,000. The roughness element produced an effect in all cases and in the majority there was an apparent transition to turbulent flow either at or downstream of the element. In those cases in which the roughness element was not too large compared to the thickness of the laminar boundary layer, the heat-transfer coefficients after the point of transition were in good accord with those predicted from the Colburn equation. The point of transition itself was in approximate agreement with values found by other experimenters.
An Experimental Study of Metal Extrusions at Various Strain Rates
Authors: Frisch J. , Thomsen E. G.
Published: July 2022

A 4.3-in-diam cylindrical commercially pure lead billet was extruded at room temperature into a 1.5-in-diam solid bar at three extrusion rates of 0.1, 0.74, and 5.15 ipm. Particle velocities, magnitude, and direction, for the inverted extrusion process using a sharp-edged die, were determined on a meridian plane by a stepwise extrusion method. It was found that for the extrusion rates investigated the flow pattern was invariable with respect to the extrusion rates. Measured wall pressures were found to increase approximately linearly with the extrusion speed in a similar manner as the extrusion load, such that the ratio of applied pressure to the wall pressure remained constant. Theoretical considerations appear to agree with the experimental observations. The mean pressure within the metal differed from the measured wall pressure by the condition necessary to establish plastic flow. The predicted mean pressure obtained from a graphical analysis of the velocity pattern of the billet agreed approximately with the measured mean pressure.
Better Yield Through Dimensional Control in Small-Sawmill Operation
Authors: Bethel J. S.
Published: July 2022

Small sawmills often are criticized on the lack of dimensional control in their products. The opportunities presented for increasing yields by control are discussed in this paper together with the realization of increased profit to the operator.
Thermal-Shocking Austenitic Stainless Steels With Molten Metals
Authors: Tidball R. A. , Shrut M. M.
Published: July 2022

Specimens of AISI 347 pipe and pipe welds have been subjected to repeated thermal shocks by quenching the inner surface with cool sodium-potassium alloy. The equipment used and a method of measuring the transient fluid and wall temperatures are described. Temperature changes encountered during tests and resulting stresses are shown. The effects of 2500 transient thermal cycles on one specimen are discussed.
Design and Operation of High-Recovery Regenerative-Type Air Preheaters: Part 2—Operation of High-Recovery Regenerative-Type Air Preheaters
Authors: Waitkus Joseph
Published: July 2022

This section of the paper is devoted to the operation of high-recovery regenerative-type air preheaters from the standpoint of removing deposits and controlling metal temperature. Emphasis is placed on several requirements for an effective removal of deposits by blowing steam or air and washing with treated water. Attention is directed to the need for a dry cleaning medium which has stimulated interest in the use of superheater steam and compressed air. The washing procedure currently recommended assures a higher degree of deposit removal with better protection from acid action. Alkalized or treated water, instead of raw water, accelerates the washing operation and produces a more thorough job. The control of metal temperature is discussed from several possible arrangements and combinations. The comparison is made of corresponding features and their effect on the operation and efficiency of the plant.
Controlled Circulation at Chesterfield
Authors: Crossan T. E. , Ryan W. F.
Published: July 2022

This paper deals with the reasons why controlled-circulation boilers were adopted for the Chesterfield Station and the economics of the installation. Early operating experience is described and more detailed descriptions of elements of the system are discussed.
The Kaplan Turbine—Design and Trends
Authors: Fisch J.
Published: July 2022

The adjustable-blade propeller turbine, known in the hydropower industry as a Kaplan turbine, in honor of its inventor, Dr. V. Kaplan of Brunn, Czechoslovakia, was first introduced in Europe in the early 1920’s and in the United States in 1928. Since then, approximately 274 units with a total output of 7,647,000 hp have been installed, or are under construction, in this country. Runner diameters vary from 30 to 292 in. and maximum operating heads for the individual units range from 7 to 105 ft. The world’s most powerful Kaplan turbine is in operation at the U. S. Engineers, McNary Dam, developing a guaranteed output of 111,300 hp under a net head of 80 ft. This output will be surpassed by the Dalles units, also for the U. S. Engineers, which are rated at 123,000 hp under 81-ft head.
The Thermal Conductivity of Fluids
Authors: Schmidt A. F. , Spurlock B. H.
Published: July 2022

In this paper an apparatus is developed which is capable of measuring the thermal conductivity of gases, vapors, and liquids over a wide range of temperatures. A compensating-type hot-wire apparatus was employed to make absolute thermal-conductivity determinations of various fluids; in particular, air was used to check the agreement of experimental results between previous investigations and the present one. In addition, the thermal conductivities of furfural vapor and liquid were measured in order to supplement existing data in the field of heat conduction with results of considerable industrial importance.
The Thermal Conductivities of Some Organic Liquids
Authors: Dick M. F. , McCready D. W.
Published: July 2022

A horizontal parallel plate apparatus was designed and constructed for the measurement of thermal conductivities of liquids. The liquid was held as a thin circular disk while the heat flux was downward through the liquid disk. The thickness of the liquid can be varied so the effect of thickness can be studied. The precision of the instrument is such that the results are within 1 per cent of the mean value. The thermal conductivities of nineteen liquid organic compounds were determined at 20 and 60 C. The compounds included isomeric ethers of varying structure, some esters of varying structure, and a hydrocarbon. All theoretical equations and empirical correlations for the prediction of the thermal conductivities of liquids were tested using the thermal conductivities of the nineteen liquids. The only available physical characteristic which would correlate the experimental results was the ASTM viscosity slope, and compounds containing rings did not correlate in this case. The experimental results were found to correlate best with the number of atoms in the longest chain. Corrections can be made for the effects of side chains and rings.
Mechanical Analog-Computing Elements and Their Applications to Automatic Control
Authors: Piatt Alvin
Published: July 2022

In this paper some representative mechanical computing elements are described. The manner in which these computing elements can be utilized in computing systems applicable to the automatic control of industrial processes also is discussed. As examples of the way in which these mechanical computing elements can be used in computers, a computing flowmeter and a multi-element controller for a heat-transfer process are described.
Proportional Control of Rate-Type Servomotors
Authors: Shearer J. L.
Published: July 2022

Optimum proportional control of various kinds of rate-type servomotors having second-order lag effects has been determined by means of an electronic-analog study. The results of this study, presented in the form of non-dimensional graphs, establish the conditions for obtaining the fastest closed-loop response with no overshoot and closed-loop response with 20 per cent overshoot. Information relating to the speed of response associated with optimum control also is given graphically. It is shown that the results of this work may be applied likewise to the floating control of second-order processes.
The Viscosity, Thermal Conductivity, and Prandtl Number for Air, O2, N2, NO, H2, CO, CO2, H2O, He, and A
Authors: Hilsenrath Joseph , Touloukian Y. S.
Published: July 2022

The low-pressure viscosity and heat-transfer parameters —thermal conductivity and Prandtl number—are tabulated for air, nitrogen, oxygen, hydrogen, argon, carbon monoxide, carbon dioxide, nitric oxide, steam, and helium. The values reported are based on recent critical correlations of the thermodynamic and transport properties of these gases at the National Bureau of Standards. The properties are tabulated for atmospheric pressure and extend from 100 K (180 R) to as high as 2000 K (3600 R) in some instances. The effect of pressure on the viscosity is presented in tabular form for oxygen, nitrogen, hydrogen, steam, carbon dioxide, and argon for pressures up to 100 atm in the experimental range of temperatures. The Prandtl numbers for air given in this work are compared with existing published and unpublished values which are in extensive use. Plots are included showing the scatter among the experimental data and deviations between them and the tabulated values. They present a very clear picture of the extent and concordance of the experimental data. A nomogram is included for obtaining fractional powers of the Prandtl number.
Stability of Gas Flow in a Tube as Related to Vertical Annular Gas-Liquid Flow
Authors: Laird A. D. K.
Published: July 2022

A model study of the pressure drop in the gas column of an upward annular gas-liquid flow system is described. The models were two rubber tubes with walls oscillating as axisymmetric standing waves. Pressure drops were shown to increase rapidly with increase of wave length, wave amplitude, and wave frequency. The mathematical analysis of the system was extended.
A Bibliography of the Frequency-Response Method as Applied to Automatic-Feedback-Control Systems
Authors: Fuchs A. M.
Published: July 2022

The frequency-response method has grown from its beginning during World War II to its present position as the principal method of analyzing and synthesizing automatic-feedback-control systems. This growth can be traced by an examination of the pertinent published material. Dividing this material into fields of interest, such as, Basic Theory; Nonlinear Systems; Books; Applications—Autopilot, Process Control, Components, and so on, makes it possible to study the development of these diverse aspects of the frequency-response method.
Determination of Transient Response From Frequency Response
Authors: Leonhard A.
Published: July 2022

When calculating the transient response of a control loop by means of the classical differential-equation method, the solution of the characteristic equation and the determination of the integration constants becomes extremely difficult for complicated configurations. If the operational calculus, i.e., the Laplace transformation, is applied, the constants of integration are produced automatically as long as definite but meaningful initial conditions are assumed, and the calculating work is simplified considerably. Even with this method, however, the roots of the characteristic equation must still be found. This presupposes that the equation can be expressed analytically, and that it can be solved, which is not always the case, as for example, if the equation is transcendental. Graphical methods have been developed for such cases, which allow the determination of the transient output response with sufficient approximation and with a moderate amount of calculating work. These methods, based on the frequency response, will be treated in detail in this paper, and their practical application will be demonstrated by means of a few problems.
A Uniform Approach to the Optimum Adjustment of Control Loops
Authors: Oldenbourg R. C. , Sartorius Hans
Published: July 2022

The paper describes the common aspects of the problems encountered in achieving optimal adjustment in all fields of automatic control. With the aid of a linear and a quadratic measure of error the general principles are obtained by considering the output behavior that follows a normalized disturbance of the equilibrium. After examining the advantages and disadvantages of these methods as well as the limits of their applicability, a method to be termed “practical optimum” is suggested, which combines general applicability with simplicity of practical handling.
A Statistical Approach to Servomechanisms and Regulators
Authors: Pélegrin M. J.
Published: July 2022

The servo field is developing rapidly in all of its aspects. The methods presently used are based upon the theory of analytic functions and consist mainly of the study of the system subjected to steady sine-wave disturbances. Recently it has been proved that, in certain cases, it is possible to compute the system directly from statistical data concerning inputs (inputs composed of “orders” and “disturbances”). The paper first reviews the results that were obtained recently by the author in this field. A particular servocircuit is computed by statistical methods, and the output autocorrelation function of a relay also is obtained. Classical and statistical methods are then used in the analysis of a variable-inertia regulator. The principal properties of the variable-inertia regulator are derived for the cases where the inertia is controlled through an external source of power and where the inertia is self-adjusted by a passive network.
Stability Characteristics of Closed-Loop Systems With Dead Band
Authors: Thomas C. H.
Published: July 2022

This paper presents a method of analyzing closed-loop systems under cyclic motion of the self-sustaining type, as caused by the presence of dead band. One common form of dead band considered occurs in mechanical linkages in conjunction with spring action, inertia, and viscous damping. The analysis is shown to be facilitated by means of an equivalent system representation. Simpler types of dead band, derivable from the more complex case, are considered. Stability criteria are developed, and the conditions are established under which sustained oscillations occur. The frequency and amplitude of oscillation may be predicted satisfactorily. Furthermore, the results are in a form which clearly indicates ways of suppressing the undesirable oscillations. One way of eliminating the hunting caused by dead band is shown. In support of the analysis the results of a differential-analyzer study are presented.
Thermometry of an optically levitated nanodiamond
Authors: Rivière François , de Guillebon Timothée , Maumet Léo , Hétet Gabriel , Schmidt Martin , Lauret Jean-Sébastien , Rondin Loïc
Published: July 2022

Using the spin properties of nitrogen-vacancy (NV) centers in levitated diamonds, we characterize the absorption of single nanodiamonds. We first calibrate the thermometry response of the NV centers embedded in our nanodiamonds. Then, using this calibration, we estimate the absorption cross-section of single levitated nanodiamonds. We show that this absorption is extrinsic and dominated by volumic effects. Our work opens the way to diamond material optimization for levitation quantum experiments. It also demonstrates optical levitation as a unique platform to characterize material thermal properties at the nanoparticle level.
REVIEWS OF ACOUSTICAL PATENTS
Authors: Fulop Sean A.
Published: July 2022

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Patents are available via the internet at the USPTO website.
Measuring competitive exclusion in non–small cell lung cancer
Authors: Farrokhian Nathan , Maltas Jeff , Dinh Mina , Durmaz Arda , Ellsworth Patrick , Hitomi Masahiro , McClure Erin , Marusyk Andriy , Kaznatcheev Artem , Scott Jacob G.
Published: July 2022

In this study, we experimentally measure the frequency-dependent interactions between a gefitinib-resistant non–small cell lung cancer population and its sensitive ancestor via the evolutionary game assay. We show that cost of resistance is insufficient to accurately predict competitive exclusion and that frequency-dependent growth rate measurements are required. Using frequency-dependent growth rate data, we then show that gefitinib treatment results in competitive exclusion of the ancestor, while the absence of treatment results in a likely, but not guaranteed, exclusion of the resistant strain. Then, using simulations, we demonstrate that incorporating ecological growth effects can influence the predicted extinction time. In addition, we show that higher drug concentrations may not lead to the optimal reduction in tumor burden. Together, these results highlight the potential importance of frequency-dependent growth rate data for understanding competing populations, both in the laboratory and as we translate adaptive therapy regimens to the clinic.
Resolving the different bulk moduli within individual soft nanogels using small-angle neutron scattering
Authors: Houston Judith Elizabeth , Fruhner Lisa , de la Cotte Alexis , Rojo González Javier , Petrunin Alexander Valerievich , Gasser Urs , Schweins Ralf , Allgaier Jürgen , Richtering Walter , Fernandez-Nieves Alberto , Scotti Andrea
Published: July 2022

The bulk modulus,
K
, quantifies the elastic response of an object to an isotropic compression. For soft compressible colloids, knowing
K
is essential to accurately predict the suspension response to crowding. Most colloids have complex architectures characterized by different softness, which additionally depends on compression. Here, we determine the different values of
K
for the various morphological parts of individual nanogels and probe the changes of
K
with compression. Our method uses a partially deuterated polymer, which exerts the required isotropic stress, and small-angle neutron scattering with contrast matching to determine the form factor of the particles without any scattering contribution from the polymer. We show a clear difference in softness, compressibility, and evolution of
K
between the shell of the nanogel and the rest of the particle, depending on the amount of cross-linker used in their synthesis.
Arrested-motility states in populations of shape-anisotropic active Janus particles
Authors: Katuri Jaideep , Poehnl Ruben , Sokolov Andrey , Uspal William , Snezhko Alexey
Published: July 2022

The emergence of large-scale collective phenomena from simple interactions between individual units is a hallmark of active matter systems. Active colloids with alignment-dominated interparticle interactions tend to develop orientational order and form motile coherent states, such as flocks and swarms. Alternatively, a combination of self-propulsion and excluded-volume interactions results in self-trapping and active phase separation into dense clusters. Here, we reveal unconventional arrested-motility states in ensembles of active discoidal particles powered by induced-charge electrophoresis. Combining experiments and computational modeling, we demonstrate that the shape asymmetry of the particles promotes the hydrodynamically assisted formation of active particles’ bound states in a certain range of excitation parameters, ultimately leading to a spontaneous collective state with arrested motility. Unlike the jammed clusters obtained through self-trapping, the arrested-motility phase remains sparse, dynamic, and reconfigurable. The demonstrated mechanism of phase separation seeded by bound state formation in ensembles of oblate active particles is generic and should be applicable to other active colloidal systems.
Peyer’s patch T
H
17 cells are dispensable for gut IgA responses to oral immunization
Authors: Gribonika Inta , Strömberg Anneli , Lebrero-Fernandez Cristina , Schön Karin , Moon James , Bemark Mats , Lycke Nils
Published: July 2022

T helper 17 (T
H
17) cells located at the Peyer’s patch (PP) inductive site and at the lamina propria effector site of the intestinal immune system are responsive to both pathogenic and commensal bacteria. Their plasticity to convert into follicular helper T (T
FH
) cells has been proposed to be central to gut immunoglobulin A (IgA) responses. Here, we used an IL-17A fate reporter mouse and an MHC-II tetramer to analyze antigen-specific CD4
+
T cell subsets and isolate them for single-cell RNA sequencing after oral immunization with cholera toxin and ovalbumin. We found a T
FH
-dominated response with only rare antigen-specific T
H
17 cells (<8%) in the PP. A clonotypic analysis provided little support that clonotypes were shared between T
FH
and T
H
17 cells, arguing against T
H
17 plasticity as a major contributor to T
FH
differentiation. Two mouse models of T
H
17 deficiency confirmed that gut IgA responses to oral immunization do not require T
H
17 cells, with

CD4
Cre
Rorc
fl/fl

mice exhibiting normal germinal centers in PP and unperturbed total IgA production in the intestine.
Monocyte-derived alveolar macrophages autonomously determine severe outcome of respiratory viral infection
Authors: Li Fengqi , Piattini Federica , Pohlmeier Lea , Feng Qian , Rehrauer Hubert , Kopf Manfred
Published: July 2022

Various lung insults can result in replacement of resident alveolar macrophages (AM) by bone marrow monocyte–derived (BMo)–AM. However, the dynamics of this process and its long-term consequences for respiratory viral infections remain unclear. Using several mouse models and a marker to unambiguously track fetal monocyte–derived (FeMo)–AM and BMo-AM, we established the kinetics and extent of replenishment and their function to recurrent influenza A virus (IAV) infection. A massive loss of FeMo-AM resulted in rapid replenishment by self-renewal of survivors, followed by the generation of BMo-AM. BMo-AM progressively outcompeted FeMo-AM over several months, and this was due to their increased glycolytic and proliferative capacity. The presence of both naïve and experienced BMo-AM conferred severe pathology to IAV infection, which was associated with a proinflammatory phenotype. Furthermore, upon aging of naïve mice, FeMo-AM were gradually replaced by BMo-AM, which contributed to IAV disease severity in a cell-autonomous manner. Together, our results suggest that the origin rather than training of AM determines long-term function to respiratory viral infection and provide an explanation for the increased severity of infection seen in the elderly.
Gut check: Intestinal microbial diversity empowers lung immunity
Authors: Clark Rachael A.
Published: July 2022

Neonatal antibiotics−induced gut dysbiosis generated hyper-inflammatory innate and exhausted T cells, reducing clearance of
S. pneumoniae
infection.
Reduced COVID-19 severity elicited by weight loss from a medically supervised ketogenic diet in a geographically diverse ambulatory population with type 2 diabetes and obesity
Authors: Volk Brittanie M , Roberts Caroline G P , VanTieghem Michelle , George M Patricia , Adams Rebecca N , Athinarayanan Shaminie J , McKenzie Amy L
Published: July 2022

Objective

To investigate factors associated with COVID-19 severity in ambulatory individuals with type 2 diabetes mellitus (T2DM) and obesity treated with a medically supervised ketogenic diet (MSKD).

Research design and methods

In this real-world, retrospective, exploratory analysis, multivariate modelling was used to assess clinical factors associated with hospitalisation for COVID-19 in a geographically diverse outpatient population with T2DM treated virtually.

Results

Leading up to COVID-19 onset, non-hospitalised patients had higher average ketones (0.64 vs 0.52 mmol/L; p=0.016) and greater weight loss (6.8% vs 4.2%; p=0.009) compared with those hospitalised. Greater weight loss was significantly associated with lower likelihood of hospitalisation (adjusted OR=0.91, p=0.005), controlling for enrolment demographics and medical characteristics.

Conclusions

Therapies such as MSKD, which elicit rapid, significant weight loss, may favourably impact COVID-19 hospitalisation rate and severity in individuals with T2DM and obesity.
Self-reported contraceptive use and satisfaction among women accessing telemedicine medical abortion at the onset of the COVID-19 pandemic at 3–6-month follow-up
Authors: Vianello Margherita , Reynolds-Wright John Joseph , Cameron Sharon
Published: July 2022

Background

Changes in legislation due to COVID-19 led to the introduction of telemedicine for early medical abortion (EMA) at home in Scotland. The opportunity to provide contraception at presentation may be more limited with this model of care. We compared contraceptive use immediately post-abortion with 3–6 months later to determine if contraceptive needs were being met.

Methods

We contacted 579 women by telephone call or text message who agreed to be involved in a service evaluation of telemedicine EMA in NHS Lothian at 3–6 months post-abortion. A research nurse administered a questionnaire on the women's current contraception use. The research nurses also offered women support in switching or initiating contraception via the abortion service if desired.

Results

The response rate to the contact was 57% (331/579). Under a third of the women (30%, 98/331) were using the progestogen-only pill (POP) at 3–6 month follow-up, a significant decrease (p<0.00) compared with 65% (215/331) who were provided with POP at the time of abortion. Thirty-nine women (12%) were provided with contraception through this telephone contact, leading to a significant increase in the proportion using subdermal implants, the progestogen injectable or intrauterine contraception.

Conclusions

This study shows that there was a decrease in the use of the POP 3–6 months after telemedicine EMA during the COVID-19 pandemic. Telephone contact at 3–6 months to facilitate obtaining contraception may be a promising strategy to improve access to effective methods with this model of abortion care.
Continuous dependence on the initial data in the Kadison transitivity theorem and GNS construction
Authors: Spiegel Daniel , Moreno Juan , Qi Marvin , Hermele Michael , Beaudry Agnès , Pflaum Markus J.
Published: July 2022

We consider how the outputs of the Kadison transitivity theorem and Gelfand–Naimark–Segal (GNS) construction may be obtained in families when the initial data are varied. More precisely, for the Kadison transitivity theorem, we prove that for any nonzero irreducible representation [Formula: see text] of a [Formula: see text]-algebra [Formula: see text] and [Formula: see text], there exists a continuous function [Formula: see text] such that [Formula: see text] for all [Formula: see text], where [Formula: see text] is the set of pairs of [Formula: see text]-tuples [Formula: see text] such that the components of [Formula: see text] are linearly independent. Versions of this result where [Formula: see text] maps into the self-adjoint or unitary elements of [Formula: see text] are also presented. Regarding the GNS construction, we prove that given a topological [Formula: see text]-algebra fiber bundle [Formula: see text], one may construct a topological fiber bundle [Formula: see text] whose fiber over [Formula: see text] is the space of pure states of [Formula: see text] (with the norm topology), as well as bundles [Formula: see text] and [Formula: see text] whose fibers [Formula: see text] and [Formula: see text] over [Formula: see text] are the GNS Hilbert space and closed left ideal, respectively, corresponding to [Formula: see text]. When [Formula: see text] is a smooth fiber bundle, we show that [Formula: see text] and [Formula: see text] are also smooth fiber bundles; this involves proving that the group of ∗-automorphisms of a [Formula: see text]-algebra is a Banach Lie group. In service of these results, we review the topology and geometry of the pure state space. A simple non-interacting quantum spin system is provided as an example illustrating the physical meaning of some of these results.
Absence of ground states in the renormalized massless translation-invariant Nelson model
Authors: Dam Thomas Norman , Hinrichs Benjamin
Published: July 2022

We consider a model for a massive uncharged non-relativistic particle interacting with a massless bosonic field, widely referred to as the Nelson model. It is well known that an ultraviolet renormalized Hamilton operator exists in this case. Further, due to translation-invariance, it decomposes into fiber operators. In this paper, we treat the renormalized fiber operators. We give a description of the operator and form domains and prove that the fiber operators do not have a ground state. Our results hold for any non-zero coupling constant and arbitrary total momentum. Our proof for the absence of ground states is a new generalization of methods recently applied to related models. A major enhancement we provide is that the method can be applied to models with degenerate ground state eigenspaces.
Per capita wealth in cities and regions fitted to Pareto, stretched exponential and econophysics Boltzmann–Gibbs distributions
Authors: Sánchez-Espinosa D. B. , Hernández-Casildo J. , Hernández-Ramírez E. , del Castillo-Mussot M.
Published: July 2022

From the years 2001 to 2017, per capita nominal and real (adjusted to inflation) GDP at purchasing power parity (PCGDP-PPP) distributions for cities and regions are fitted to various functions. For most years and regions, real PCGDP-PPP data are very well adjusted to the one-parameter Boltzmann–Gibbs distribution (BGD), in accordance with the exponential behavior predicted by the simple econophysics analogy between conserved money in economic trade and energy in elastic collisions in gases. Overall, fittings are better for large regions in recent years, which may reflect an increasing economic globalization in time. Cities, small regions and large regions values are well fitted by stretched exponential distributions.
INVESTMENT DYNAMICS OF SINGAPORE STOCK AND REAL ESTATE MARKETS
Authors: LIOW KIM HIANG , SONG JEONGSEOP , JUSTIN LAU JUN CHENG
Published: July 2022

This paper examines investment dynamics of six major Singapore asset markets (general stock, property stock, residential, office, retail and industrial) over the last 45 years by focusing on their dynamic correlations, varying spillover-connectedness, Granger causal dependence and selective frequency return connectedness to understand better the changing market relationships among the six markets, as well as the wealth effects between the stock and housing markets. We find that the six asset markets have not become more correlated over time. The 2007–2009 global financial crisis has created the most severe contagion among the markets and was followed by Singapore economic recession. Although these six markets were quite moderately connected in their returns and risk, the return and risk connectedness index measures reached their respective low levels in recent years. The net directional connectedness of the six markets varies in different periods of domestic economic development, external financial crisis and domestic economic recession. Moreover, the housing market leads significant causal interactive roles (linear and nonlinear) over other property and stock markets. On the other hand, the stock market is a strong return transmitter for most of the research periods. The long-term horizon was the most important in contributing to the leadership position in return connectedness of housing market during the Asian financial crisis. Finally, a key message derived from this “long-period” study is that an in-depth understanding of the various investment dynamics is crucial to help maximize mixed portfolio diversification benefits and managing risk in Singapore stock and property markets in the long run.
Fermion mass hierarchies and mixings in B − L model with Δ(27) × Z4 symmetry
Authors: Vien V. V.
Published: July 2022

In this study, a gauge [Formula: see text] model with [Formula: see text] symmetry is suggested to explain the fermion masses, mixings and hierarchies. We show that the Yukawa couplings in the lepton and quark sectors reach a range only about two orders of magnitude. The smallness of the light neutrino masses, fermion masses and mixings is obtained via the type-I seesaw mechanism. The model is predictive since it can reproduce the realistic lepton and quark mixing patterns, as well as predict the effective neutrino parameters of [Formula: see text] eV and [Formula: see text] eV which are highly consistent with the recent constraints.
Boltzmann and Tsallis statistical approaches to study quantum corrections at large distances and clustering of galaxies
Authors: Hameeda M. , Gani Q. , Pourhassan B. , Rocca M. C.
Published: July 2022

Gravity is so different from other fundamental forces that it is now essentially treated as a nonfundamental force of entropic origin. Several good studies have been carried out in this direction. Quantum gravity is a theory which combines gravity well with quantum physics. However, there are still many impediments to our understanding, especially in the limits of extreme. The effects of quantum gravity start appearing on the scene at Planck length which is the smallest length in nature idealized so far. Although this study incorporates a model which is valid for potential energy corrections at small distances, we have also given a bold try to use it consistently for the corrections at very large distances as well. The model uses two techniques, namely, Boltzmann and Tsallis statistical approaches to explore the thermodynamics within the ambit of the braneworld model giving its further modified version. We have computed the partition function by using both Boltzmann and Tsallis statistical approaches and then used it to study the thermodynamics of the braneworld model. We have analyzed both analytically and graphically, the thermodynamic quantities like Helmholtz free energy and specific heat.
Witten index for weak supersymmetric systems: Invariance under deformations
Authors: Smilga Andrei
Published: July 2022

When a 4D supersymmetric theory is placed on [Formula: see text], the supersymmetric algebra is necessarily modified to [Formula: see text] and we are dealing with a weak supersymmetric system. For such systems, the excited states of the Hamiltonian are not all paired. As a result, the Witten index [Formula: see text] is no longer an integer number, but a [Formula: see text]-dependent function.

However, this function stays invariant under deformations of the theory that keep the supersymmetry algebra intact. Based on the Hilbert space analysis, we give a simple general proof of this fact. We then show how this invariance works for two simplest weak supersymmetric quantum mechanical systems involving a real or a complex bosonic degree of freedom.
Root Cause Analysis of Anomalies Based on Graph Convolutional Neural Network
Authors: Li Zhongliang , Tu Yaofeng , Ma Zongmin
Published: July 2022

With the gradual increase of network complexity and network scale in the cloud environment, Root Cause Analysis (RCA) of node failures has become a systematic problem of great research significance. This paper proposes Graph-Attention-Sage (GASage) algorithm, which is a fault RCA algorithm and scheme. The algorithm solves the RCA by incorporating TOPK sampling and Attention-Aggregation with GraphSage algorithm in large-scale and complex microservice network environment. The GASage algorithm is based on graph convolutional neural network and graph attention mechanism, which profoundly combines the characteristics of network fault RCA problems. TOPK sampling mechanism is applied in GASage to select the neighboring nodes with the top [Formula: see text] highest correlation as the objectives to be aggregated. GASage adopts an attention mechanism when aggregated, which aggregates the features of the central node according to the weights of the adjacent nodes and the central node. The weight aggregation method can greatly improve the node representation effect in the RCA scenario. The empirical results of our experiments have demonstrated that the model learned with GASage can outperform other model with the same learning framework and achieves more than 10% improvement in precision.
On row-factorization relations of certain numerical semigroups
Authors: Bhardwaj Om Prakash , Goel Kriti , Sengupta Indranath
Published: July 2022

Let [Formula: see text] be a numerical semigroup minimally generated by an almost arithmetic sequence. We give a description of a possible row-factorization (RF) matrix for each pseudo-Frobenius element of [Formula: see text]. Further, when [Formula: see text] is symmetric and has embedding dimension four or five, we prove that the defining ideal is minimally generated by RF-relations.
The order of the unitary subgroups of group algebras
Authors: Balogh Zsolt Adam
Published: July 2022

Let [Formula: see text] be the group algebra of a finite [Formula: see text]-group [Formula: see text] over a finite field [Formula: see text] of positive characteristic [Formula: see text]. Let ⊛ be an involution of the algebra [Formula: see text] which is a linear extension of an anti-automorphism of the group [Formula: see text] to [Formula: see text]. If [Formula: see text] is an odd prime, then the order of the ⊛-unitary subgroup of [Formula: see text] is established. For the case [Formula: see text] we generalize a result obtained for finite abelian [Formula: see text]-groups. It is proved that the order of the ∗-unitary subgroup of [Formula: see text] of a non-abelian [Formula: see text]-group is always divisible by a number which depends only on the size of [Formula: see text], the order of [Formula: see text] and the number of elements of order two in [Formula: see text]. Moreover, we show that the order of the ∗-unitary subgroup of [Formula: see text] determines the order of the finite [Formula: see text]-group [Formula: see text].
Analysis of cross-section, S-factor and thermonuclear reaction rate of 8Li(α,n)11B and 14N(p,γ)15O using TALYS and EMPIRE nuclear reaction codes
Authors: Mondal Satabdi , Das Pampa , Senapati Enakshi , Pandit Deepak , Dey Balaram , De Alokkumar , Bhattacharya Srijit
Published: July 2022

Theoretical nuclear reaction codes are crucial for studying cross-section and S-factors of nuclear reactions required for the thermonuclear reaction rate calculations. We analyze two reactions 8Li([Formula: see text])11B and 14N([Formula: see text])15O, using both TALYS and EMPIRE codes. We stress that these reactions are highly important for CNO cycle but the extent of involvement of experimental datasets are meager and conflicting. For the first reaction, the trend of experimental data has been predicted satisfactorily by the codes. The reaction rate is also matched with REACLIB calculation. However, in 14N([Formula: see text])15O, none of the codes could predict the resonant structures in the experimental data at the lower energies. The importance of our work is a sincere attempt to validate the TALYS and EMPIRE predictions for cross-section, S-factor and the reaction rate, simultaneously.
The Capitalized Generalized Autoregressive Conditional Heteroskedasticity
Authors: Kola Katlego , Sebehela Tumellano
Published: July 2022

The aim of this paper is to shed new light on hedging discrete volatilities, in particular when using the generalized autoregressive conditional heteroskedasticity (thereafter GARCH) model. Despite its elegance, GARCH does not account for (i) correlation coefficients of debt and equity, (ii) equity parameter, (iii) risk premium, (iv) interest rates, and (v) shocks-stock markets. The unaccounted listed parameters are included into the GARCH(1,1) and the paper inverts a new model, expanded GARCH, called the capitalized GARCH. The results show that the capitalized GARCH convergences in a similar manner to the GARCH(1,1) in modeling volatility of bonds, commodities, equities, and real estate indices.
Retail Investors and Stock Price Synchronicity
Authors: Wu Wenfeng , Rui Oliver M.
Published: July 2022

In this study, we use the number of retail investors in China’s stock market to investigate how retail investors affect stock price synchronicity. We find that a higher number of retail investors in a firm is associated with higher stock price synchronicity. Moreover, we trace this association to two sources. One is a negative effect of the number of retail investors on the probability of informed trading (PIN), suggesting that retail investors generate arbitrage risk which discourages informed trading. The other is a positive influence of the number of retail investors on price comovement (beta), resulting from correlated trading among retail investors.
Turań-type inequalities for two hypergeometric supertrigonometric functions associated with Kummer confluent hypergeometric series of first type
Authors: Geng Lu Lu , Yang Xiao Jun
Published: July 2022

In the paper, on account of the Kummer confluent hypergeometric series of first type, we suggest the Turań-type inequalities for the hypergeometric supersine and supercosine functions by using the Cauchy–Bunyakovsky–Schwarz inequality.
Asymptotic stability in a mosquito population suppression model with time delay
Authors: Hui Yuanxian , Zhao Zhong , Li Qiuying , Pang Liuyong
Published: July 2022

In this paper, a delayed mosquito population suppression model, where the number of sexually active sterile mosquitoes released is regarded as a given nonnegative function, and the birth process is density dependent by considering larvae progression and the intra-specific competition within the larvae, is developed and studied. A threshold value [Formula: see text] for the releases of sterile mosquitoes is determined, and it is proved that the origin is globally asymptotically stable if the number of sterile mosquitoes released is above the threshold value [Formula: see text]. Besides, the case when the number of sterile mosquitoes released stays at a constant level [Formula: see text] is also considered. In the special case, it is also proved that the origin is globally asymptotically stable if and only if [Formula: see text] and that the model exhibits other complicated dynamics such as bi-stability and semi-stability when [Formula: see text]. Numerical examples are also provided to illustrate our main theoretical results.
Dynamical analysis and optimal control for a delayed viral infection model
Authors: Li Fei , Zhang Suxia , Xu Xiaxia
Published: July 2022

To describe the interaction between viral infection and immune response, we establish a mathematical model with intracellular delay and investigate an optimal control problem to examine the effect of antiviral therapy. Dynamic analysis of the proposed model for the stability of equilibria and Hopf bifurcation is conducted. Theoretical results reveal that the dynamical properties are determined by both the immune-inactivated reproduction number and the immune-activated reproduction number. With the aim of minimizing the infected cells and viral load with consideration for the treatment costs, the optimal solution is discussed analytically. Numerical simulations are performed to suggest the optimal therapeutic strategy and compare the model-predicted consequences.
Are measured InSAR displacements a function of the chosen processing method?
Authors: Scoular Jennifer , Ghail Richard , Mason Philippa , Lawrence James
Published: July 2022

The benefits of InSAR to the civil engineering industry have been demonstrated on many occasions, however there is still a limited uptake by end-users, due to perceived differences between data providers and uncertainty around how to interpret results. This paper critically compares three datasets for London: Radarsat-2 (RS2) from 2011 to 2015, TerraSAR-X (TSX) from 2011 to 2017, and Sentinel-1 (STL1) from 2015 to 2017. Two of the datasets (TSX & RS2) were processed by commercial data providers, while the STL1 data were processed using ENVI
®
SARscape
®
by the authors. The results show an inverse relationship between the Pearson Correlation Coefficient and absolute total displacement of Persistent Scatterers (PS). There is a strong correlation between datasets for total displacement greater than 5 mm, but a weak or no correlation in the 0–3 mm range. Consequently, standard commercial InSAR datasets, processed with no
a priori
knowledge of the area of interest, have error margins below 3–5 mm but correctly detect all deformation phenomena exceeding this threshold. RS2-TSX both capture the spatial extent of the investigated area of dewatering induced subsidence, however STL1 measures a much broader, less pronounced zone of heave than TSX.

Thematic collection:
This article is part of the Remote sensing for site investigations on Earth and other planets collection available at:
https://www.lyellcollection.org/cc/remote-sensing-for-site-investigations-on-earth-and-other-planets