scholarly journals X. A method of measuring the pressure produced in the detonation of high, explosives or by the impact of bullets

1914 ◽  
Vol 213 (497-508) ◽  
pp. 437-456 ◽  
Keyword(s):  
Practical Interest ◽  
Direct Determination ◽  
High Explosives ◽  
Time Curve ◽  
Considerable Difficulty ◽  
Cylindrical Steel ◽  
Set Up ◽  
The Right ◽  
The Impact

The determination of the actual pressures produced by a blow such as that of a rifle bullet or by the detonation of high explosives is a problem of much scientific and practical interest but of considerable difficulty. It is easy to measure the transfer of momentum associated with the blow, which is equal to the average pressure developed, multiplied by the time during which it acts, but the separation of these two factors has not hitherto been effected. The direct determination of a force acting for a few hundred-thousandths of a second presents difficulties which may perhaps be called insuperable, but the measurement of the other factor, the duration of the blow, is more feasible. In the case of impacts such as those of spheres or rods moving at moderate velocities the time of contact can be determined electrically with considerable accuracy.* The present paper contains an account of a method of analysing experimentally more violent blows and of measuring their duration and the pressures developed. If a rifle bullet be fired against the end of a cylindrical steel rod there is a definite pressure applied on the end of the rod at each instant of time during the period of impact and the pressure can be plotted as a function of the time. The pressure-time curve is a perfectly definite thing, though the ordinates are expressed in tons and the abscissae in millionths of a second; the pressure starts when the nose of the bullet first strikes the end of the rod and it continues until the bullet has been completely set up or stopped by the impact. Subject to qualifications, which will be considered later, the result of applying this varying pressure to the end is to send along the rod a wave of pressure which, so long as the elasticity is perfect, travels without change of type. If the pressure in different sections of the rod be plotted at any instant (fig. l) then at a later time the same curve shifted to the right by a distance proportional to the time will represent the then distribution of pressure. The velocity with which the wave travels in steel is approximately 17,000 feet per second. As the wave travels over any section of the rod, that section successively experiences pressures represented by the successive ordinates of the curve as they pass over it. Thus the curve also represents the relation between the pressure at any point of the rod and the time, the scale being such that one inch represents the time taken by the wave to travel that distance which is very nearly 1/200,000 of a second. In particular the curve giving the distribution of pressure in the rod along its length is, assuming perfect elasticity, the same as the curve connecting the pressure applied at the end and the time, the scale of time being that just given.

Predictive modelling of hospital readmission: Evaluation of different preprocessing techniques on machine learning classifiers

2021 ◽  
Vol 25 (5) ◽  
pp. 1073-1098
Author(s):  
Nor Hamizah Miswan ◽  
Chee Seng Chan ◽  
Chong Guan Ng
Keyword(s):  
Machine Learning ◽  
Hospital Readmission ◽  
Performance Metrics ◽  
Predictive Performance ◽  
Predictive Modelling ◽  
Machine Learning Classifiers ◽  
Learning Classifiers ◽  
Set Up ◽  
The Right ◽  
The Impact

Hospital readmission is a major cost for healthcare systems worldwide. If patients with a higher potential of readmission could be identified at the start, existing resources could be used more efficiently, and appropriate plans could be implemented to reduce the risk of readmission. Therefore, it is important to predict the right target patients. Medical data is usually noisy, incomplete, and inconsistent. Hence, before developing a prediction model, it is crucial to efficiently set up the predictive model so that improved predictive performance is achieved. The current study aims to analyse the impact of different preprocessing methods on the performance of different machine learning classifiers. The preprocessing applied by previous hospital readmission studies were compared, and the most common approaches highlighted such as missing value imputation, feature selection, data balancing, and feature scaling. The hyperparameters were selected using Bayesian optimisation. The different preprocessing pipelines were assessed using various performance metrics and computational costs. The results indicated that the preprocessing approaches helped improve the model’s prediction of hospital readmission.

scholarly journals Nonperturbative Uncertainties on the Transverse Momentum Distribution of Electroweak Bosons and on the Determination of the W Boson Mass at the LHC

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Giuseppe Bozzi ◽  
Andrea Signori
Keyword(s):  
Transverse Momentum ◽  
W Boson ◽  
Direct Determination ◽  
Boson Mass ◽  
Proton Proton ◽  
Theoretical Predictions ◽  
Quark Transverse Momentum ◽  
The Impact ◽  
Proton Proton Collisions

In this contribution we present an overview of recent results concerning the impact of a possible flavour dependence of the intrinsic quark transverse momentum on electroweak observables. In particular, we focus on the qT spectrum of electroweak gauge bosons produced in proton-proton collisions at the LHC and on the direct determination of the W boson mass. We show that these effects are comparable in size to other nonperturbative effects commonly included in phenomenological analyses and should thus be included in precise theoretical predictions for present and future hadron colliders.

scholarly journals Continuous action right knife unit with ground interaction analysis

2020 ◽  
Vol 17 (4) ◽  
pp. 452-463
Author(s):  
V. A. Nikolayev ◽  
D. I. Troshin
Keyword(s):  
Total Energy ◽  
Soil Layer ◽  
Practical Interest ◽  
Longitudinal Force ◽  
Energy Costs ◽  
Continuous Action ◽  
Action Unit ◽  
The Face ◽  
The Right ◽  
The Impact

Introduction. To solve the problem of accelerating the construction of roads, improving their quality, it is advisable to use a continuous action unit to form a underlying layer. The main working bodies of this unit are buckets, which cut off the soil layer from below and on the side. At the same time, the bottom knife cuts off the ground layer from below, the right knife on the side, and the console knife partially cuts the top layer of soil from below for the next bucket. In particular, the analysis of interaction with the soil of the right knife of the continuous action unit is of theoretical and practical interest. To do this, the right knife is divided into elements and analyzed the interaction of these elements with the ground. The consistent impact on the soil of many right knives, within the width of the grip of the unit, is replaced by the impact on the ground of one conventional right knife at a distance necessary for the development of one cubic meter of soil. The forces of interaction of the conventional right knife with the ground are called conditional forces.The method of research. The method for calculating the energy costs during punching the right knife into the ground is shown: on separating the formation of the ground from its body, on overcoming the ground friction on the edge of the blade, on overcoming the ground pressure on the edge of the blade, on accelerating the ground of the blade by means of the axle, on overcoming the ground friction on the shelf, to overcome the ground friction against the outside surface.The total energy costs of interacting with a soil of one cubic meter are derived from the addition of private energy costs. The method of calculating the horizontal longitudinal force needed to move the right knife is given.Results. On the basis of the methodology developed, energy costs are calculated when introducing the right knife into the ground: on separating the soil from its body, on overcoming the friction of the ground on the edge of the blade, on overcoming the pressure of the ground on the face of the blade, on the acceleration of the ground with a fascia blade, on overcoming the ground friction on the face. The total energy costs of the right knife interact with the soil of one cubic meter. The horizontal long-lived force needed to move the right knife has been determined.Conclusion. As a result of the calculations: the energy needed to cut the ground with the right knives, more than 71 J/cube. The horizontal longitudinal force needed to move the right knife is 730 N. To determine the total energy spent on cutting the ground by buckets of the unit to remove the top layer of soil from the underlying layer of the road, it is necessary to analyze the interaction with the soil of other elements of the bucket.

scholarly journals INFLUENCE OF ERRORS IN DETERMINATION OF TRACING SLOPE ON THE ACCURACY OF GEODETIC BASE FOR ROUTE

2021 ◽  
pp. 111-117
Author(s):  
Kostiantyn Mamonov ◽  
Svitlana Kamchatnaya ◽  
Yevhen Orel ◽  
Oleksandr Saiapin
Keyword(s):  
High Speed ◽  
Methodological Approach ◽  
Line Length ◽  
Route Length ◽  
The Difference ◽  
Artificial Development ◽  
The Right ◽  
The Impact ◽  
Further Development

The purpose of this article is to study and develop a methodological approach tosolving the problem of accuracy of the geodetic base of the route. For this purpose, the followingtasks are set: mathematical substantiation the dependence of the line length on the ratio of the traceslope and the guide slope; description of the function of optimal use of the guiding slope at highspeed; determination of the impact of errors in the course of the geodetic justification on the routelength. Starting from the determined point and further to the right, artificial development of the lineis required. Because when a trace is planed using level curves, this point can be reached sooner orlater, and in some cases, this point can not be reached not at all, the line length designed accordingto the plan will be slightly different than in the case of tracing with usage the exact data. Thus, theobtained results indicate the following. If the error positions during a high-speed segment are suchthat the ordnance datum of the passage is less than the truth, the route length will be less than thetrue and vice versa. This trivial result indicates that the location of geodetic support points ondifferent sides of the pass is not recommended. It is established that due to the accumulation of errorsin the transmission of coordinates in the working substantiation networks, the conditions of the linedesign and the amount of operating costs change. It is mathematically substantiated that the linelength depends on the depth of the excavation on the pass and the height of the embankment at thepoint, and also on the difference of ordnance datum at these points. The difference between the traceslope and the guiding slope has an inversely proportional effect. In addition, the function of optimaluse of the guide slope at a high-speed segment has the form of a broken line according to its fracturesthe need for artificial development of the route can be established. The influence of errors in the course of the working justification is manifested in the discrepancy between the true and projectedroute length. If this error is not taken into account, it will lead to significant overspending duringbuilding a longer line than necessary. Further development of the problem of increasing the accuracyof tracing and reducing the impact of errors is planned in the direction of creating methods of digitalmodelling and automated programs.

scholarly journals Visibility study of Galileo satellites from a VLBI network

2021 ◽  
Author(s):  
Helene Wolf ◽  
Johannes Böhm ◽  
Matthias Schartner ◽  
Urs Hugentobler
Keyword(s):  
Reference Frames ◽  
Direct Determination ◽  
Satellite Constellation ◽  
Long Baseline ◽  
Space Geodetic Techniques ◽  
Satellite Scheduling ◽  
Observation Geometry ◽  
The Impact

<p>Over the last years, ideas have been proposed to install a Very Long Baseline Interferometry (VLBI) transmitter on one or more satellites of the Galileo constellation. Satellites transmitting signals that can be observed by VLBI telescopes provide the opportunity of extending the current VLBI research with observations to geodetic satellites. These observations offer a variety of new possibilities such as high precision tying of space geodetic techniques but also the direct determination of the absolute orientation of the satellite constellation with respect to the International Celestial Reference Frame (ICRF) and have implications on the determination of long-term reference frames. </p><p>This contribution provides a visibility study of the Galileo satellites from a VLBI network. The newly developed satellite scheduling module in VieSched++ is used to determine the time periods during which a satellite is observable from a VLBI network. The possible satellite observations are evaluated through the number of stations from which a satellite is observable. Moreover, the impact on determining the orientation of the satellite constellation, caused by the observation geometry, is investigated with using the UT1-UTC Dilution of Precision (UDOP) factor.</p>

scholarly journals Discharge Flow Rate for the Initiation of Jet Flow in Sky-Jump Spillways

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1814
Author(s):  
Raffaella Pellegrino ◽  
Miguel Ángel Toledo ◽  
Víctor Aragoncillo
Keyword(s):  
Flow Rate ◽  
Direct Determination ◽  
Jet Flow ◽  
Effective Solution ◽  
Discharge Flow Rate ◽  
Impact Area ◽  
Experimental Laboratory ◽  
New Formula ◽  
The Impact

The sky-jump spillway is an economical and effective solution to return water to a river, eventually complemented by a pre-excavated basin. However, an inappropriate design could endanger spillways and even the dam itself. For the design of a sky-jump it is necessary to evaluate the position and dimensions of the potential pre-excavated basin based on the characteristics of the water flow to be evacuated and the geometric configuration of the sky-jump. The jump of the water jet occurs when a certain flow rate is reached. This flow rate for the initiation of the jet flow determines the position of the impact area closest to the spillway. We propose a new formula for the determination of the flow rate for the initiation of the jet flow, which incorporates as a novelty the influence of the curvature of the flip bucket. A methodology for the direct determination of the flow rate for the initiation of the jet flow is also presented. The new formula and methodology, based on experimental laboratory work and numerical modeling, will support the designer to choose the energy dissipation way, in the riverbed or inside the flip bucket, for low and frequent discharge flows.

scholarly journals Three-Dimensional Salt Dynamics in Well-Mixed Estuaries: Influence of Estuarine Convergence, Coriolis, and Bathymetry

2017 ◽  
Vol 47 (7) ◽  
pp. 1843-1871 ◽  
Author(s):  
Xiaoyan Wei ◽  
Mohit Kumar ◽  
Henk M. Schuttelaars
Keyword(s):  
Coriolis Force ◽  
Three Dimensional ◽  
Temporal Correlation ◽  
Salt Transport ◽  
Residual Circulation ◽  
Three Dimensional Model ◽  
Coriolis Effects ◽  
Set Up ◽  
The Right ◽  
The Impact

AbstractA semianalytical three-dimensional model is set up to dynamically calculate the coupled water motion and salinity for idealized well-mixed estuaries and prognostically investigate the influence of each physical mechanism on the residual salt transport. As a study case, a schematized estuary with an exponentially converging width and a channel–shoal structure is considered. The temporal correlation between horizontal tidal velocities and tidal salinities is the dominant process for the landward residual salt transport. The residual salt transport induced by residual circulation is locally significant, but the induced salt transport integrated over the cross section is small. The impacts of the estuarine geometry, Coriolis force, and bathymetry on the salt dynamics are studied using three dedicated experiments, in which the impact of each of these factors is studied separately. To assess the impact of width convergence, a convergent estuary without bathymetric variations or Coriolis force is considered. In this experiment, the temporal correlation between tidal velocities and salinities is the only landward salt transport process. In the second experiment, Coriolis effects are included. This results in a significant residual salt transport cell due to the advection of the tidally averaged salinity by residual circulation, with salt imported into the estuary from the left side and exported on the right (looking seaward). In the last experiment, a lateral channel–shoal structure is included while the Coriolis effects are excluded. This results in a significant landward salt transport through the deeper channel and a seaward salt transport over the shoals due to the advection of the tidally averaged salinity by residual circulation.

scholarly journals Chemical Analysis through CL-Detection Assisted by Periodate Oxidation

2007 ◽  
Vol 2007 ◽  
pp. 1-10 ◽  
Author(s):  
Nicholaos P. Evmiridis ◽  
Athanasios G. Vlessidis ◽  
Nicholas C. Thanasoulias
Keyword(s):  
Chemical Analysis ◽  
Flow Injection ◽  
Research Work ◽  
Periodate Oxidation ◽  
Direct Determination ◽  
Good Reproducibility ◽  
Through Flow ◽  
Set Up ◽  
Simple Flow

The progress of the research work of the author and his colleagues on the field of CL-emission generated by pyrogallol oxidation and further application for the direct determination of periodate and indirect or direct determination of other compounds through flow-injection manifold/CL-detection set up is described. The instrumentation used for these studies was a simple flow-injection manifold that provides good reproducibility, coupled to a red sensitive photomultiplier that gives sensitive CL-detection. In addition, recent reports on studies and analytical methods based on CL-emission generated by periodate oxidation by other authors are included.

scholarly journals A method of measuring the pressure produced in the detonation of high explosives or by the impact of bullets

1914 ◽  
Vol 89 (612) ◽  
pp. 411-413 ◽  
Keyword(s):  
Pressure Wave ◽  
Total Pressure ◽  
Total Duration ◽  
Maximum Pressure ◽  
Velocity Of Sound ◽  
High Explosives ◽  
Magnetic Attraction ◽  
Ballistic Pendulum ◽  
Cylindrical Steel ◽  
The Impact

If a rifle bullet be fired against the end of a cylindrical steel rod, or some gun-cotton be detonated in its neighbourhood, a wave of pressure is transmitted along the rod with the velocity of sound. If the pressure in different sections of the rod be plotted at any instant of time, the abscissae being distances along the rod, then at a later time the same curve shifted through a distance proportional to the time will represent the then distribution of pressure. Also the same curve represents the relation between of the pressure across any section of the rod and the time, the scale of time being approximately 2 inches for 10 -5 seconds. In particular it represents the relation between the total pressure applied to the end of the rod and the time, and the length of the curve represents the total duration of the blow. If the rod be divided at a point a few inches from the far end, the opposed surfaces of the cut being in firm contact and carefully faced, the wave of pressure travels practically unchanged through the joint. At the free end it is reflected as a wave of tension, and the pressure at any section is then to be obtained by adding the effects of the pressure wave and the tension wave. At the joint the pressure continues to act until the head of the reflected tension wave arrives there. If the tail of the pressure wave has then passed the joint the end-piece flies off, having trapped within it the whole of the momentum of the blow, and the rest of the rod is left completely at rest. The length of end-piece which is just sufficient completely to stop the rod is half the length of the pressure wave, and the duration of the blow is twice the time taken by the pressure wave to travel the length of the end-piece. Further, it is easy to see, as is proved in detail in the paper, that the momentum trapped in quite short end-pieces will be equal to the maximum pressure multiplied by twice the time taken by the wave in traversing the end-piece. Thus by experimenting with different lengths of end-pieces and determining the momentum with which each flies off the rod as- the result of the blow it is possible to measure both the duration of the blow and the maximum pressure developed by it. This is the basis of the experimental method described in the paper. A steel rod is hung up as a ballistic pendulum, and the piece is held on to the end by magnetic attraction.

scholarly journals Two-tier proportional electoral system in Ukraine: cross-regional analysis of the first approbation

2021 ◽  
pp. 62-79
Author(s):  
Oleksandr Fisun ◽  
◽  
Anton Avksentiev ◽  
Keyword(s):  
Regional Analysis ◽  
Electoral System ◽  
Local Elections ◽  
Party Leaders ◽  
High Figure ◽  
The Right ◽  
The Impact ◽  
The Relationship

The article examines some effects from the first approbation of a two-tier proportional system with „flexible” lists in the local elections in Ukraine in 2020. In the comparative-regional context, the impact of the new system on the increase in the number of invalid ballots is analyzed and the percentage of voters who exercised the right to preferential voting for a particular candidate from the district list of the elected party is calculated. Hypotheses about regional differences in these quantitative parameters are formulated: in particular, the share of invalid ballots may be influenced by ethnolinguistic and urban factors. It was found that about 80% of voters who took part in the autumn 2020 vote exercised the right to preferential voting by entering the number of a particular candidate on the ballot – this unexpectedly high figure is in the context of other national cases using proportional systems with „flexible” or clean „open” lists. Particular attention is focused on the relationship between the two levels of the electoral system – the single closed and district flexible lists, and, accordingly, the balance of influence of voters and party leaders on the passage of candidates to local councils. This ratio was calculated for all oblast councils, and the material of the Kharkiv and Lviv oblast councils determined the empirical probability of changing the order of candidates in the district party lists under the influence of voters. Although supporters and lobbyists called the introduction of a new electoral system in Ukraine a model with „open” lists, the article identifies two key institutional mechanisms for significantly downplaying the role of preferential voting in the final determination of candidates. It is argued that according to the results of the personal distribution of seats among the candidates in the party lists, this model of „flexible” lists was closer to the pole of „closed” than „open” lists. Keywords: electoral systems, electoral lists, Electoral Сode of Ukraine, proportional electoral system, „flexible” lists, preferential voting, invalid ballots.

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