scholarly journals Exploring Torricelli's theorem with Arduino

2021 ◽  
Vol 4 (04) ◽  
pp. 22-28
Author(s):  
Ana Carolina Maranni ◽  
Robert Rogger de Lima ◽  
Diogo Duarte dos Reis ◽  
Alem-Mar B Goncalves
Keyword(s):  
Water Column ◽  
Theoretical Models ◽  
Flow Meter ◽  
Discharge Velocity ◽  
Distance Sensor ◽  
Pvc Pipe ◽  
Coefficient Of Discharge ◽  
Made In

We explore the dynamics of the water in a PVC pipe during the drain using two independent sensors simultaneously. We track the height of the water column and the discharge velocity of the water through the hole made in the lower part of the pipe. The ultrasonic distance sensor and the flow meter used as sensors were controlled by an Arduíno board. The acquired data follows the theoretical models but, with a coefficient of discharge smaller than 1.

Confirmation of Solar-Like Oscillations in η Bootis

2002 ◽  
Vol 185 ◽  
pp. 470-471
Author(s):  
H. Kjeldsen ◽  
T.R. Bedding ◽  
I.K. Baldry ◽  
S. Frandsen ◽  
H. Bruntt ◽  
...  
Keyword(s):  
Theoretical Models ◽  
Frequency Separation ◽  
Balmer Line ◽  
Average Amplitude ◽  
Optical Telescope ◽  
Oscillation Modes ◽  
Excess Power ◽  
Large Frequency ◽  
Line Equivalent Width ◽  
Made In

Kjeldsen et al. (1995) detected excess power in the GO subgiant η Boo from measurements of Balmer-line equivalent widths. The excess was at the expected level, and these authors were able to extract frequency separations and individual frequencies which agreed well with theoretical models (Christensen-Dalsgaard et al., 1995; Guenther & Demarque, 1996). A more detailed discussion of theoretical models for η Bootis was given by Di Mauro & Christensen-Dalsgaard (2001).Kjeldsen et al. (1995) estimated the average amplitude of the strongest modes to be 7 times solar, corresponding to 1.6 m/s in velocity. 13 individual oscillation modes were identified consistent with a large frequency separation of 40.3 μHz. We note, however, that a search for velocity oscillations in this star by Brown et al. (1997) failed to detect a signal, setting limits at a level below that expected on the basis of the Kjeldsen et al. result.In this paper we report further observations made in 1998. We observed this star in Balmer-line equivalent width with the 2.5-m Nordic Optical Telescope and in velocity with the 24-inch Lick CAT.

Trophic group and the end-Cretaceous extinction: did deposit feeders have it made in the shade?

Paleobiology ◽  
1996 ◽  
Vol 22 (1) ◽  
pp. 104-112 ◽  
Author(s):  
Jeffrey S. Levinton
Keyword(s):  
Water Column ◽  
Deep Sea ◽  
Trophic Group ◽  
Food Shortage ◽  
Suspension Feeders ◽  
Deposit Feeders ◽  
Relative Ability ◽  
Organic Particles ◽  
Cretaceous Period ◽  
Made In

It has been suggested that a sudden event at the end of the Cretaceous period caused a major extinction that was felt disproportionately by creatures in the water column. It also has been argued that benthic deposit feeders, being relatively independent of abundance of organic particles in the water column, should have survived the crisis more readily than suspension feeders, which depended more upon feeding upon phytoplankton. I argue that the hypothesis of relative immunity of deposit feeders is insufficient, because deposit feeders by and large depend upon a supply of organic matter from the water column and would have succumbed to food shortage nearly as rapidly as suspension feeders, possibly within a maximum of three to six months. This near simultaneity of extinction would have been especially true of continental shelf environments. Even in some parts of the deep sea, it is likely that a dependence upon the water column above might have caused deep-sea deposit feeders to succumb rapidly. Therefore, deposit feeders would not necessarily have outsurvived suspension feeders during a crisis of depleted water-column phytoplankton, increased shading by inert particles, or poisoning of the water column and killing of phytoplankton. The relatively lower rate of extinction of nuculoid bivalves may relate instead to their presence in deeper-water refuge habitats, their apparent relative ability to diversify in higher latitudes, or their resistance to factors other than food shortage.

Experiments on filtration in plankton nets

1967 ◽  
Vol 18 (1) ◽  
pp. 89 ◽  
Author(s):  
DJ Tranter ◽  
AC Heron
Keyword(s):  
Water Column ◽  
Flow Patterns ◽  
Filtration Efficiency ◽  
Wind Tunnels ◽  
Gradual Decline ◽  
Test Tank ◽  
Suitable Site ◽  
Made In

Experiments were carried out in wind tunnels, in a test tank, and at sea, to investigate the interaction between the water column and a towed plankton net. Flow patterns about stationary nets held in a stream of air were observed and photographed. The velocity and turbulence of the stream near the net, and the drag upon the net, were measured. Experimental tows were made in the laboratory and in the field to test the effect of various factors on "filtration efficiency". This interaction between the discharge and the flow around the net leads to enhanced filtration. The effect is accentuated by a flared mouth which increases the velocity differential. The effect is reduced by encasing the net, which separates the interacting streams and probably causes the stream from the net surface to lose momentum. Filtration efficiency is independent of towing velocity, except for a gradual decline at velocities less than 1-2 kt. Filtration efficiency is also independent of filtering area in nets of usual length, but declines sharply in nets shorter than twice their mouth diameter. There is a zone of turbulence and reduced velocity in the centre of a net with bridles. At approximately one-quarter of a radius from the ring, the stream is flowing at mean mouth velocity. This seems to be the most suitable site for a flowmeter.

Magnetic fields in the solar photosphere

2008 ◽  
Vol 366 (1884) ◽  
pp. 4465-4476 ◽  
Author(s):  
Paul J Bushby
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Active Regions ◽  
Theoretical Models ◽  
Solar Photosphere ◽  
Complex Field ◽  
Theoretical Understanding ◽  
Magnetic Features ◽  
Localized Magnetic Field ◽  
Made In

Recent high-resolution observations of the surface of the Sun have revealed the fine structure of a vast array of complex photospheric magnetic features. Observations of these magnetic field structures have already greatly enhanced our theoretical understanding of the interactions between magnetic fields and turbulent convection, and future photospheric observations will inevitably present new theoretical challenges. In this review, I discuss recent progress that has been made in the modelling of photospheric magnetic fields. In particular, I focus upon the complex field structures that are observed within the umbrae and the penumbrae of sunspots. On a much smaller scale, I also discuss models of the highly localized magnetic field structures that are observed in less magnetically active regions of the photosphere. As the spatial resolution of telescopes has improved over the last few years, it has now become possible to observe these features in detail, and theoretical models can now describe much of this behaviour. In the last section of this review, I discuss some of the remaining unanswered questions.

Intensity Profile of Electron Beam

1970 ◽  
Vol 28 ◽  
pp. 52-53
Author(s):  
S. M. Ohr ◽  
T. S. Noggle
Keyword(s):  
Electron Beam ◽  
Theoretical Models ◽  
Effective Area ◽  
Oak Ridge ◽  
Black And White ◽  
Viewing Screen ◽  
Shadow It ◽  
Electron Dosimetry ◽  
Made In

In situ studies of electron displacement damage in graphite are being made in Oak Ridge using a 200 kV Hitachi HU 200-E electron microscope. Examples of the damage structure that develops in the area upon which the illuminating beam is incident are shown in Fig. 1. The spot structures (both black and white) are identified as clusters of interstitial atoms. It is of particular interest in this study to have accurate electron dosimetry in order to relate the damage structures to theoretical models. In this paper we wish to report on the technique and some preliminary results obtained in measuring the intensity profiles of the electron beam.Measurements of the beam profiles have been made by replacing one of the side windows of the viewing chamber with a 1” brass plate in which is mounted a retractable arm which can insert a Faraday cup into a position on the axis and at a level approximately one-third the distance from the projector lens to the viewing screen. This arrangement allows one to take pictures with the cup in position, and from the shadow it casts determine its effective area in the magnified image of the beam.

Design, Construction, and Programming of a Mobile Robot Controlled by Artificial Vision

2019 ◽  
pp. 411-431
Author(s):  
Claudio Urrea ◽  
Alex Yau
Keyword(s):  
Mobile Robot ◽  
Mobile Robotics ◽  
Artificial Vision ◽  
Precise Positioning ◽  
Surrounding World ◽  
Distance Sensor ◽  
Design Construction ◽  
Made In

The design, construction and programming of a mobile robot controlled by means of artificial vision, capable of recognizing, grabbing and moving specific objects in a completely autonomous way is presented, together with the conceptual and theoretical-practical grounds for the work. A mechanically robust robot is built and a system is designed, allowing the mobility of two sensors jointly, i.e., artificial vision camera and distance sensor. This makes it possible to improve the range of artificial vision, over approximately 180°, achieving precise positioning of the mobile robot. The artificial vision camera, CMUCam 2, provides the mobile robot with great autonomy thanks to its excellent interaction with its surrounding world. Having a mobile robot like this will allow interesting developments to be made in various areas of mobile robotics.

Efficacy of anuran trapping and monitoring techniques in the tropical forests of Bioko Island, Equatorial Guinea

2018 ◽  
Vol 39 (4) ◽  
pp. 435-444
Author(s):  
Alexis Mraz ◽  
Mark Weir ◽  
Patrick McLaughlin
Keyword(s):  
Equatorial Guinea ◽  
Pitfall Traps ◽  
Pitfall Trapping ◽  
Effective Utilization ◽  
Bioko Island ◽  
Monitoring Techniques ◽  
Tropical Environments ◽  
Pvc Pipe ◽  
Effective Use ◽  
Made In

Abstract Anurans are of particular importance in monitoring the ecosystems of tropical environments. Existing literature reveals little standardization in methodology, and many of the techniques that have been shown to be effective in deciduous environments, such as polyvinyl chloride (PVC) refuges and pitfall traps, are either inadequate or too difficult to implement in tropical environments. This study evaluated three anuran trapping and monitoring techniques for use in a tropical environment: PVC pipe refuges, pitfall traps, and anuran census. Prior research validated the use of PVC refuges and pitfall traps in deciduous forests, but their use outside of the Americas has not been thoroughly examined. PVC refuges failed to attract anurans in this study, likely due to the abundance of natural refugia characteristic of tropical environments with dense foliage. Pitfall traps utilizing 19-liter buckets are difficult to implement in rocky soil and were shown to be ineffective utilizing buckets small enough to implement in this research. The modifications to the pitfall traps made in this research allowed for effective use with smaller, easier to install buckets. The anuran census described in this study utilizes established trails or paths for a continuous census. This study shows evidence for the effective utilization of both modified pitfall trapping and anuran census in monitoring population densities, assessing species richness, and detecting the presence of rare or cryptic species.

scholarly journals Old and New from Multifrequency Astrophysics

2014 ◽  
Vol 1 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Franco Giovannelli ◽  
Lola Sabau-Graziati
Keyword(s):  
Review Paper ◽  
Theoretical Models ◽  
Short Review ◽  
Experimental Results ◽  
Energy Bands ◽  
The Past ◽  
Limited Length ◽  
The Many ◽  
Made In

In this short review paper we comment on some the most important steps that have been made in the past decades for a better understanding of the physics governing our Universe. The results we discuss come from the many groundand-space-based experiments developed for measuring astrophysical sources in various energy bands. These experimental results are discussed within the framework of current theoretical models. Because of the limited length of this paper, we have selected only a few topics that, in our opinion, have been crucial for the progress of our understanding of the physics of cosmic sources.

Dissolved gases in perennially ice-covered lakes of the McMurdo Dry Valleys, Antarctica

1998 ◽  
Vol 10 (2) ◽  
pp. 124-133 ◽  
Author(s):  
D.T. Andersen ◽  
C.P. Mckay ◽  
R.A. Wharton
Keyword(s):  
Water Column ◽  
Turbulent Mixing ◽  
Bubble Formation ◽  
Gas Content ◽  
Main Process ◽  
Water Interface ◽  
Dry Valleys ◽  
The Mean ◽  
Ice Water ◽  
Made In

Measurements of dissolved N2, O2, Ar, CO2, and CH4 were made in perennially ice-covered Lake Hoare. Results confirm previous reports that O2 concentrations in the upper water column exceed atmospheric equilibrium and that N2 and Ar are supersaturated throughout the water column. The mean supersaturation of N2 was found to be 2.0 (±0.37) and Ar was 3.8 (±1.1). The ratios of N2/Ar (20.3 ±3.8), and O2/Ar (22.5 ±4.0) at the ice-water interface are consistent with those previously measured, suggesting that bubble formation is the main process for removing gas from the lake. However, the saturations of N2 and Ar greatly exceed those previously predicted for degassing by bubble formation only at the ice-water interface. The data support the hypothesis that removal of gas by bubbles occurs in the water column to a depth of 11 m in Lake Hoare. CO2 concentration increases from near zero at the ice-water interface to 80–100 times saturation at and below the chemocline at c. 28 m. There is considerable variability in the gas concentrations throughout the water column; samples separated in depth by one metre may vary by more than 50% in gas content. It is likely that this phenomenon results from the lack of turbulent mixing in the water column. Methane (c. 2 μg 1−1) was detected below the chemocline and immediately above the sediment/water interface at a depth of 30 m. Samples from lakes Vanda, Joyce, and Miers, also show supersaturations of O2, N2, and Ar at levels similar to levels found in Lake Hoare.

scholarly journals The prevalence of violence towards the elderly: a critical review of the literature

1970 ◽  
Author(s):  
Ana João Santos ◽  
Rita Nicolau ◽  
Ana Alexandre Fernandes ◽  
Ana Paula Gil
Keyword(s):  
Public Perception ◽  
Theoretical Models ◽  
The Elderly ◽  
Population Based ◽  
Anglo Saxon ◽  
Prevalence Studies ◽  
European Public ◽  
Research Designs ◽  
Definition Of ◽  
Made In

The studies on the prevalence of violence towards the elderly in a family context that have been conducted in the last thirty years, especially in Europe and Anglo-Saxon countries, are not sufficiently elucidative. This is due to shortcomings in both the definition of their theoretical models and their operative  concepts. The authors of this article have systematically reviewed the literature and identified a diversity of definitions and research designs, which has an inevitable impact in terms of varying estimates. The European public perception of this problem is also at odds with the low figures contained in this type of estimate. The authors offer somethoughts about the underlying reasons for these representations, and critique the estimates made in population-based prevalence studies.

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