scholarly journals Droplet Fate in a Cough Puff

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 841 ◽  
Author(s):  
Paolo Martano
Keyword(s):  
Environmental Conditions ◽  
Size Range ◽  
Equations Of Motion ◽  
Gravitational Settling ◽  
Surface Evaporation ◽  
Switching Threshold ◽  
Seasonal Behaviour ◽  
Temperature And Humidity ◽  
Spherical Cloud ◽  
Basic Equations

The dynamic and thermodynamic evolution of droplets, in a size range characterizing a cough, has been analysed using basic equations of motion and coupled to the evolution of a spherical cloud puff in which they are supposed to be expired. It has been found that the maximum contamination range of the emitted droplets is controlled by two different mechanisms: surface evaporation and inertia-gravitational settling—with a switching threshold between them for a radius around a few tens of microns. For the smallest droplets, the environmental conditions (the temperature and humidity) are found to be very effective in determining the contamination range, even for weak entrainment in the cloud puff. This last fact could be of some relevance in the seasonal behaviour of air-borne epidemics.

scholarly journals Symmetry analysis of rotating fluid

2005 ◽  
Vol 47 (1) ◽  
pp. 65-74 ◽  
Author(s):  
K. Fakhar ◽  
Zu-Chi Chen ◽  
Xiaoda Ji
Keyword(s):  
Steady State ◽  
Infinite Number ◽  
Special Function ◽  
Equations Of Motion ◽  
Time Dependent ◽  
Lie Theory ◽  
Rotating Fluid ◽  
Type Solution ◽  
Function Type ◽  
Basic Equations

AbstractThe machinery of Lie theory (groups and algebras) is applied to the unsteady equations of motion of rotating fluid. A special-function type solution for the steady state is derived. It is then shown how the solution generates an infinite number of time-dependent solutions via three arbitrary functions of time. This algebraic structure also provides the mechanism to search for other solutions since its character is inferred from the basic equations.

scholarly journals Construction And Test Of Thermostats And Twirlers For Molecular Rotations

2003 ◽  
Vol 58 (7-8) ◽  
pp. 377-391 ◽  
Author(s):  
Siegfried Hess
Keyword(s):  
Time Reversal ◽  
Rotational Diffusion ◽  
Equations Of Motion ◽  
Dynamical Variable ◽  
Two Dimensional ◽  
Polymer Molecules ◽  
Isotropic Harmonic Oscillator ◽  
Molecular Rotations ◽  
Basic Equations ◽  
Nonlinear Elastic

The equations of motion are coupled with a dynamical variable, referred to as twirler, which randomizes the angular momentum. The equations are time-reversal invariant, just as those for the standard Gaussian, Nosé-Hoover and configurational thermostats. The derivation of the basic equations is outlined. Test calculations are performed for the two-dimensional isotropic harmonic oscillator and for a nonlinear elastic dumbbell, used as a simple model to study properties of polymer molecules. Graphs of characteristic quantities and orbits, some of which are rather intriguing, are displayed. As applications, the rotational diffusion and the influence of a shear flow on the angular velocity and the deformation of the model polymer are analyzed.

Nonlinear Dynamic Response of a Tension Leg Platform

1999 ◽  
Vol 121 (4) ◽  
pp. 219-226 ◽  
Author(s):  
P. Bar-Avi
Keyword(s):  
Environmental Conditions ◽  
Nonlinear Dynamic ◽  
Equations Of Motion ◽  
Continuous System ◽  
Offshore Structures ◽  
Physical Parameters ◽  
Wave Forces ◽  
Tension Leg Platform ◽  
Nonlinear Dynamic Response ◽  
Nonlinear Equations Of Motion

Of the classes of offshore structures, the tension leg platform (TLP) is particularly well suited for deepwater operation. The structure investigated in this paper is assumed to consist of a flexible cable attached to a buoyant deck at the top. The cable is modeled as a beamlike continuous system subjected to wave, current, and wind forces. The derivation of the nonlinear equations of motion include nonlinearities due to geometry as well as due to wave forces. The equations of motion are solved and the TLP’s response to various environmental conditions and other physical parameters is evaluated.

scholarly journals Plesio-geostrophy for Earth’s core: I. Basic equations, inertial modes and induction

2020 ◽  
Vol 476 (2243) ◽  
pp. 20200513
Author(s):  
Andrew Jackson ◽  
Stefano Maffei
Keyword(s):  
Rotation Axis ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Normal Modes ◽  
Planetary Cores ◽  
Motional Induction ◽  
Basic Equations ◽  
Short Time ◽  
Magnetic Case

An approximation is developed that lends itself to accurate description of the physics of fluid motions and motional induction on short time scales (e.g. decades), appropriate for planetary cores and in the geophysically relevant limit of very rapid rotation. Adopting a representation of the flow to be columnar (horizontal motions are invariant along the rotation axis), our characterization of the equations leads to the approximation we call plesio-geostrophy , which arises from dedicated forms of integration along the rotation axis of the equations of motion and of motional induction. Neglecting magnetic diffusion, our self-consistent equations collapse all three-dimensional quantities into two-dimensional scalars in an exact manner. For the isothermal magnetic case, a series of fifteen partial differential equations is developed that fully characterizes the evolution of the system. In the case of no forcing and absent viscous damping, we solve for the normal modes of the system, called inertial modes. A comparison with a subset of the known three-dimensional modes that are of the least complexity along the rotation axis shows that the approximation accurately captures the eigenfunctions and associated eigenfrequencies.

scholarly journals Perancangan Jaringan Sensor Nirkabel (JSN) untuk Memantau Suhu dan Kelembaban Menggunakan nRF24L01+

2014 ◽  
Vol 2 (4) ◽  
pp. 267 ◽  
Author(s):  
Dwi Intan Af'idah ◽  
Adian Fatchur Rochim ◽  
Eko Didik Widianto
Keyword(s):  
Environmental Conditions ◽  
Sensor Node ◽  
Sensor Nodes ◽  
Environmental Condition ◽  
Maximum Range ◽  
Temperature And Humidity ◽  
Communication Module ◽  
And Control ◽  
Fertilization Experiments ◽  
Monitoring Temperature

The environmental condition in a large areas often requires the monitoring. For example, in the case of greenhouse were used to cultivation experiments, fertilization experiments, plant resistance experiments, tissue culture experiments, experimental planting of crops in the off-season, and it needs equipment to monitor and control the environmental conditions to suit the characteristics required environment. The extent of land that is must be monitored, making it needs distribute the monitor at some point so that monitoring of environmental conditions can cover the entire desired area. This is the basis for the design of wireless sensor network for monitoring temperature and humidity using the communication module nRF24L01 +. The system consists of hardware for measuring the temperature and humidity at some point in a certain area. The system is divided into several sections that is referred to as nodes. Node in the system is divided into two functions, namely the sensor node and the concentrator node.. There are two the sensor nodes which will serve to data of temperature and humidity in separate areas and transmit data to the concentrator node. The communication between nodes is done using a module nRF24L01+. The design of communication protocol designed to connect between nodes concentrator with a sensor node capable of running properly. This makes the system capable of monitoring temperature and humidity through a web page, so it can be known conditions of temperature and humidity at some point at the maximum range of 93 meters.

scholarly journals CONSTRUCTION AND RESEARCH OF FULL BALANCE ENERGY OF VARIATIONAL PROBLEM MOTION SURFACE AND GROUNDWATER FLOWS

2017 ◽  
Vol 1 ◽  
pp. 45-52
Author(s):  
Petro Venherskyi
Keyword(s):  
Variational Problem ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Variational Problems ◽  
Energy System ◽  
Problem Solution ◽  
Flow Energy ◽  
Balance Energy ◽  
Basic Equations ◽  
Surface And Groundwater

Based on the laws of conservation of mass and momentum the basic equations of motion with unknown quantities velocity and piezometric pressure are written. These equations are supplemented with boundary and initial conditions describing the motion of compatible flows. Based on the laws of motion continuum, received conditions contact on the common border interaction of surface and groundwater flows. Variational problems formulated compatible flow. Energy norms of basic components of variational problem are analyzed. Correctness of constructing variational problem arising from construction of the energy system of equations that allow to investigate properties of the problem solution, its uniqueness, stability, dependence on initial data and more. Energy equation of motion of surface and groundwater flows are derived and investigated. It is shown that the total energy compatible flow depends on sources that are located inside the domain or on its border.

scholarly journals Enabling experimental greenhouse for high-tech application

2021 ◽  
pp. 9-18
Author(s):  
Martín Eduardo Rodríguez-Franco ◽  
Víctor Arturo Maldonado-Ruelas ◽  
Francisco Javier Villalobos-Piña ◽  
Raúl Arturo Ortiz-Medina
Keyword(s):  
Environmental Conditions ◽  
Effective Interaction ◽  
High Tech ◽  
Graphical Interface ◽  
Open Communication ◽  
Labview Software ◽  
Temperature And Humidity ◽  
System Controller ◽  
Communication Standard

This work exposes the conditioning of the zenith greenhouse of the Polytechnic University of Aguascalientes for its conformation as a high-tech entity, through the adaptation of sensors, actuators and a controller, which ensure the supervision of the environmental conditions inside, mainly established by the variables of temperature and humidity. The development and application of a computer graphical interface is presented as an intuitive tool for monitoring and controlling the field devices used, and therefore, the environmental conditions provided or recorded from their activation. Likewise, the use of the open communication standard OPC is demonstrated as an alternative for effective interaction between the LabVIEW software, from which the management interface was developed, and the PLC, used as the system controller. The results achieved provide proof of the adequate operation of the devices adapted in the greenhouse installation, the compilation of the information associated with the performance of their task and the manipulation of their operation or reading, from the graphical interface developed for this purpose.

scholarly journals A general fluid–sediment mixture model and constitutive theory validated in many flow regimes

2018 ◽  
Vol 861 ◽  
pp. 721-764 ◽  
Author(s):  
Aaron S. Baumgarten ◽  
Ken Kamrin
Keyword(s):  
Constitutive Model ◽  
Equations Of Motion ◽  
Material Point ◽  
Mixed System ◽  
Two Phase ◽  
Mixture Phase ◽  
State Behaviour ◽  
Steady Shearing ◽  
Basic Equations ◽  
Sediment Mixture

We present a thermodynamically consistent constitutive model for fluid-saturated sediments, spanning dense to dilute regimes, developed from the basic balance laws for two-phase mixtures. The model can represent various limiting cases, such as pure fluid and dry grains. It is formulated to capture a number of key behaviours such as: (i) viscous inertial rheology of submerged wet grains under steady shearing flows, (ii) the critical state behaviour of grains, which causes granular Reynolds dilation/contraction due to shear, (iii) the change in the effective viscosity of the fluid due to the presence of suspended grains and (iv) the Darcy-like drag interaction observed in both dense and dilute mixtures, which gives rise to complex fluid–grain interactions under dilation and flow. The full constitutive model is combined with the basic equations of motion for each mixture phase and implemented in the material point method (MPM) to accurately model the coupled dynamics of the mixed system. Qualitative results show the breadth of problems which this model can address. Quantitative results demonstrate the accuracy of this model as compared with analytical limits and experimental observations of fluid and grain behaviours in inhomogeneous geometries.

The effect of environmental temperature and humidity on the respiration rate of Ayrshire calves

1955 ◽  
Vol 45 (4) ◽  
pp. 452-460 ◽  
Author(s):  
W. R. Beakley ◽  
J. D. Findlay
Keyword(s):  
Respiration Rate ◽  
Experimental Animal ◽  
Environmental Conditions ◽  
Environmental Temperature ◽  
Absolute Humidity ◽  
Saturation Deficit ◽  
Respiration Rates ◽  
Bull Calves ◽  
Temperature And Humidity ◽  
Frequency Of Respiration

1. The respiration rates of three 4-month old Ayrshire bull calves were measured in individual 6 hr. daily exposures to 15, 20, 25, 30, 35 and 40° C. dry bulb temperatures at 17 mg./l. absolute humidity and at 7 mg./l. saturation deficit at temperatures of 30, 35 and 40° C. in a planned sequence of environmental temperature. The schedule of experiments on each animal lasted 45 days consisting of five replications of these nine environmental conditions. Throughout the experimental programme the respiration rates of these three animals and of three control animals were measured in a holding room just before the experimental animal of each pair was transferred to the hot room.2. The frequency of respiration of all the calves increased with increasing environmental temperature and humidity.

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