scholarly journals Analysis of PDA measurements in double injection GDI sprays

2017 ◽  
Author(s):  
Lucio Araneo ◽  
Robert Dondè ◽  
Lucio Postrioti ◽  
Andrea Cavicchi
Keyword(s):  
Short Distance ◽  
Ambient Air ◽  
Injection Rate ◽  
Droplet Velocity ◽  
Appreciable Effect ◽  
Time Length ◽  
Double Injection ◽  
Phase Doppler Anemometry ◽  
Photographic Analysis ◽  
The One

A N-heptane spray from a GDI multi-hole injector operated in ambient air at fixed conditions and with doubleinjection commands is studied with different experimental techniques to better understand the spray behaviors, focusing the analysis on the effect of different dwell times between the two pulses. Results from spray photographic analysis, fuel injected quantity, droplet velocity and sizing by Phase Doppler Anemometry are presented and compared.  The peculiarities and usefulness of a complementary application of the different techniques is illustrated. The two spray pulses have the same time length, so that the first spray evolves in a nearly quiescent and clean ambient, while the second, nominally identical to the first one, evolves in its trailing edge. The direct comparison allows an immediate perception of the differences among the two sprays, at the different dwell times, where the shorter tested, 160 microseconds, was chosen as the one that shows the first appreciable effect with at least one of the used techniques; the differences are clearly evident in the PDA results, sufficiently visible from the injection rate, not appreciable in the imaging at short distance. The effect of the longerdwell times becomes more evident and is illustrated.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.5007

Global Warming and Its Multiple Causes

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Romdhane Ben Slama
Keyword(s):  
Global Warming ◽  
Greenhouse Gases ◽  
Greenhouse Effect ◽  
Infrared Radiation ◽  
Fossil Fuels ◽  
Ambient Air ◽  
The Earth ◽  
The One ◽  
Heat Released ◽  
Emission Of Greenhouse Gases

The global warming which preoccupies humanity, is still considered to be linked to a single cause which is the emission of greenhouse gases, CO2 in particular. In this article, we try to show that, on the one hand, the greenhouse effect (the radiative imprisonment to use the scientific term) took place in conjunction with the infrared radiation emitted by the earth. The surplus of CO2 due to the combustion of fossil fuels, but also the surplus of infrared emissions from artificialized soils contribute together or each separately,  to the imbalance of the natural greenhouse effect and the trend of global warming. In addition, another actor acting directly and instantaneously on the warming of the ambient air is the heat released by fossil fuels estimated at 17415.1010 kWh / year inducing a rise in temperature of 0.122 ° C, or 12.2 ° C / century.

Гігієнічні нормативи хімічних речовин в атмосферному повітрі: досягнення минулого та сучасні погляди у майбутнє

2021 ◽  
pp. 51-57
Author(s):  
I.O. Chernychenko ◽  
◽  
O.M. Lytvychenko ◽  
V.F. Babii ◽  
N.V. Balenko ◽  
...  
Keyword(s):  
Air Pollution ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Monitoring Methods ◽  
Chemical Agents ◽  
Regulatory Frameworks ◽  
The Usa ◽  
Averaging Time ◽  
The One ◽  
Acute And Chronic Effects

Objective: We generalized and assessed the prior chemical pollutants in accordance with the time of their averaging by the data of domestic and foreign regulatory frameworks. Materials and methods: To achieve the goal, we used the bibliographic and analytical methods. We analyzed the databases of Ukraine and the EU countries, the USA and Canada on the current standards for chemical agents and the time of their averaging in accordance with the purpose - prevention of acute and chronic effects. Results and discussion: As a result of the comparison of the data on the regulations and standards for chemical agents in ambient air, we identified the agents that are criterial ones in most countires. For these substances, monitoring methods have been developed and standards have been substantiated and adopted for two averaging periods: twenty-minute and average daily. In most countries, two standards have been also adopted for each agent, but the averaging period is longer there: an average annual and a daily average. Such standards may control and prevent the chronic effect of substances. As a result, the use of the Ukrainian and foreign standards leads to the controversial estimates of the actual air pollution. The average daily standard adopted in Ukraine, on the one hand, is much stricter in comparison with the similar foreign criteria, and on the other hand, it does not correspond to the peculiarities of the formation of ambient air pollution, and is inadequate for the averaging time. Conclusions: 1. Comparative analysis of hygienic standards indicates the needs to harmonize the ambient air quality standards in force in Ukraine with international ones. 2. The existing system of the hygienic standards in Ukraine must be supplemented with the standard for the annual averaging period by transferring the operating average daily concentrations to this rank.

Origins

2018 ◽  
Author(s):  
Peter Mitchell
Keyword(s):  
Short Distance ◽  
Cervical Vertebra ◽  
Genetic Studies ◽  
Human Interactions ◽  
The Third ◽  
Wild Ass ◽  
History Of ◽  
Kill Site ◽  
The One ◽  
The Right

Over 50,000 years ago a Neanderthal hunter approached a wild ass on the plains of northeastern Syria. Taking aim from the right as the animal nervously assessed the threat, he launched his stone-tipped spear into its neck, penetrating the third cervical vertebra and paralyzing it immediately. Butchered at the kill site, this bone and most of the rest of the animal were taken back to the hunter’s camp at Umm el Tlel, a short distance away. Closely modelled on archaeological observations of that vertebra and the Levallois stone point still embedded within it, this incident helps define the framework for this chapter. At the start of the period it covers, human interactions with the donkey’s ancestors were purely a matter of hunting wild prey, but by its end the donkey had been transformed into a domesticated animal. Chapter 2 thus looks at how this process came about, where it did so, and what the evolutionary history of the donkey’s forebears had been until that point. Donkeys and the wild asses that are their closest relatives form part of the equid family to which zebras and horses also belong. Collectively, equids, like rhinoceroses and tapirs, fall within the Perissodactyla, the odd-toed division of hoofed mammals or ungulates. Though this might suggest a close connection with the much larger order known as the Artiodactyla, the even-toed antelopes (including deer, cattle, sheep, and goats), their superficial resemblances may actually reflect evolutionary convergence; some genetic studies hint that perissodactyls are more closely related to carnivores. Like tapirs and rhinoceroses, the earliest equids had three toes, not the one that has characterized them for the past 40 million years. That single toe, the third, now bears all their weight in the form of a single, enlarged hoof with the adjacent toes reduced to mere splints. This switch, and the associated elongation of the third (or central) metapodial linking the toe to the wrist or ankle, is one of the key evolutionary transformations through which equids have passed. A second involves diet since the earliest perissodactyls were all browsers, not grazers like the equids of today.

scholarly journals CALCULATION OF THE Bc LEPTONIC DECAY CONSTANT USING THE SHIFTED N-EXPANSION METHOD

2006 ◽  
Vol 21 (32) ◽  
pp. 6699-6714 ◽  
Author(s):  
SAMEER M. IKHDAIR ◽  
RAMAZAN SEVER
Keyword(s):  
Short Distance ◽  
Decay Constant ◽  
Expansion Method ◽  
Leptonic Decay ◽  
Scaling Relation ◽  
Potential Models ◽  
The One ◽  
Distance Coefficient

We give a review and present a comprehensive calculation for the leptonic constant fBc of the low-lying pseudoscalar and vector states of Bc-meson in the framework of static and QCD-motivated nonrelativistic potential models taking into account the one-loop and two-loop QCD corrections in the short distance coefficient that governs the leptonic constant of Bc quarkonium system. Further, we use the scaling relation to predict the leptonic constant of the nS-states of the [Formula: see text] system. Our results are compared with other models to gauge the reliability of the predictions and point out differences.

Detection of mantle CO2 in an underground salt mine via long-term and high-resolution monitoring by laser-based isotope techniques

2020 ◽  
Author(s):  
Alexander H. Frank ◽  
Robert van Geldern ◽  
Anssi Myrttinen ◽  
Axel Zimmer ◽  
Martin Zimmer ◽  
...  
Keyword(s):  
Ambient Air ◽  
High Temporal Resolution ◽  
Anthropogenic Influences ◽  
Salt Mine ◽  
Central Germany ◽  
Salt Mines ◽  
Set Up ◽  
The One ◽  
Isotope System

<p>Salt deposits may be affected by post-depositional CO<sub>2</sub> intrusions. In central Germany, such CO<sub>2</sub> contributions from the mantle may originate from Tertiary Rhön- and Vogelsberg-volcanism. The intrusion of those gases may cause technical and operational implications for storage caverns and salt mines.</p><p>Carbon isotope compositions of CO<sub>2</sub> are useful tools to differentiate between sources and are expressed as δ<sup>13</sup>C values in ‰ versus an international standard known as the Vienna Pee Dee Belemnite (VPDB). Typical average endmember values for CO<sub>2</sub> from the mantle are -5.1 ‰, while background air and anthropogenic influences range around averages of -11.9 ‰ and -29.8‰. Detection of fluctuations between these endmembers can be challenging with discrete sampling. This can be overcome by high-temporal resolution and long-term monitoring.</p><p>Towards this purpose, a laser-based isotope system was set up in an active underground salt mine in central Germany. For 34 days, continuous measurements of δ<sup>13</sup>C and concentrations of CO<sub>2</sub> were generated close to a site where mantle CO<sub>2</sub> intrusions were suspected. A timer regularly switched intakes from two capillaries, of which one was placed inside a borehole and the other in ambient air of the mine. Measured CO<sub>2</sub> concentrations ranged between 700 and 1600 ppmV, while δ<sup>13</sup>C values ranged between -21.5 ‰ and -11.5 ‰. Lower concentrations coincided with more positive isotope values and occurred around weekends when anthropogenic influences in the mine were less.</p><p>While influences of fresh air venting may have caused these weekly shifts, the admixture of mantle CO<sub>2</sub> seemed to play a continuous role. This is because small differences between the capillary from the borehole and the one with ambient air existed throughout the time series. Our results indicate that short-term dynamics on the order of hours to days are overlain by admixtures mantle gas intrusions of CO<sub>2</sub>.</p>

scholarly journals Realization of Maxwell’s Hypothesis: A Heat-Electric Conversion in Contradiction to the Kelvin Statement

2019 ◽  
Author(s):  
Xinyong Fu ◽  
Zitao Fu
Keyword(s):  
Uniform Magnetic Field ◽  
Room Temperature ◽  
Electric Energy ◽  
Ambient Air ◽  
Second Law ◽  
Heat Reservoir ◽  
Net Migration ◽  
The One ◽  
A Charge ◽  
Static Uniform Magnetic Field

In a vacuum tube, two identical and parallel Ag-O-Cs surfaces, A and B, with a work function 0.8eV, ceaselessly emit thermal electrons at room temperature. The thermal electrons are controlled by a static uniform magnetic field (a magnetic demon), and the number of electrons migrate from A to B exceeds the one from B to A (or vice versa). The net migration from A to B quickly results in a charge distribution, with A charged positively and B negatively. A potential difference between A and B emerges, and the tube outputs an electric current and a power to a load (a resistance, e.g.). The ambient air is a single heat reservoir in the experiment, and all the heat extracted by the tube from the air is converted into electric energy without producing other effects. We believe the experiment is in contradiction to the Kelvin statement of the second law.

scholarly journals The Classical Topography of the Roman Campagna.–I.

1902 ◽  
Vol 1 ◽  
pp. 126-285 ◽  
Author(s):  
T. Ashby
Keyword(s):  
Short Distance ◽  
The Other ◽  
Sufficient Information ◽  
Long Distance ◽  
The Road ◽  
Local Roads ◽  
City Gates ◽  
The One ◽  
The City ◽  
Road System

It is a tendency of all great cities to possess two distinct and often independent sets of communications, the one for local, the other for long-distance traffic; and, unless a city has suddenly sprung into being, it will be found that, in order of development, the former precedes and is the germ of the latter. In the case of Rome, we are able to trace with remarkable clearness the successive stages of the development of the road system. The roads which, when this system had attained its perfection, we find radiating in all directions from the city, may be divided into two groups. The first of these, the local roads, take their name from the cities to which they lead; the second, the longdistance roads, from those who were chiefly responsible for their construction. All, however, must have originated as short-distance roads, leading to some town or other, and if we possessed sufficient information as to the spread of the Roman supremacy in Italy, we should be able to trace step by step the development of the long-distance roads from the local ones in every case. For the growth of the road system is intimately connected with the growth of the power of Rome. As soon as we are able to fix approximately the earliest bounds of her territory, we find her enclosed within very narrow limits. Except along the banks of the Tiber, her dominion extended hardly five miles from the city gates.

scholarly journals On the permeability of transparent screens of extreme tenuity by radiant heat

1833 ◽  
Vol 2 ◽  
pp. 310-311
Keyword(s):  
Thin Film ◽  
Elevated Temperatures ◽  
Ambient Air ◽  
Radiant Heat ◽  
The Other ◽  
Small Aperture ◽  
The One

The author states in this paper, that invisible radiant heat, from sources at elevated temperatures, freely permeates thin transparent screens in the same manner as light; but that as this doctine, established by Profesor Prévost and M. de la Roche has been controverted, he thinks it necessary to demonstrate it by fresh experiments: to this end he covered a small aperture with a film of glass almost iridescent, and keeping it constantly cold, by blowing on it, below the temperature of ambient air, he found that afi air-thermometer on one side of it was not affected by a heated iron ball on the other, if the temperature of the ball was low; but that as this temperature was raised, though not to the point of visible ignition, the effect on the thermometer became Sensible and even considerable. In another experiment, two air-thermometers, having their bulbs transparent, and as thin as possible, were placed equidistant from a heated ball just ceasing to be visible in the dark. The one was clear, the other coated inside with a thin film of pounded charcoal. The latter was most affected.

scholarly journals Realization of Maxwell’s Hypothesis: A Heat-Electric Conversion in Contradiction to the Kelvin Statement

2019 ◽  
Author(s):  
Xinyong Fu ◽  
Zitao Fu
Keyword(s):  
Uniform Magnetic Field ◽  
Room Temperature ◽  
Electric Energy ◽  
Ambient Air ◽  
Second Law ◽  
Heat Reservoir ◽  
Net Migration ◽  
The One ◽  
A Charge ◽  
Static Uniform Magnetic Field

In a vacuum tube, two identical and parallel Ag-O-Cs surfaces, A and B, with a work function of 0.8eV, ceaselessly emit thermal electrons at room temperature. The thermal electrons are controlled by a static uniform magnetic field (a magnetic demon), and the number of electrons migrate from A to B exceeds the one from B to A, (or vice versa). The net migration from A to B quickly results in a charge distribution: A charged positively and B negatively. A potential difference between A and B emerges, and the tube outputs ceaselessly an electric current and a power to a resistance (a load) and cools itself slightly. The ambient air is a single heat reservoir in the experiment, and all the heat extracted by the tube from the air is converted into electric energy without producing other effect. We believe the experiment is in contradiction to the Kelvin statement of the second law.

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