29 research outputs found
Recommended from our members
An Evaluation of Electrostatic Lofting and Subsequent Particle Motion on Bennu
No full textElectrostatic lofting is the detachment of particles from a surface that occurs if the electrostatic force on the particles is greater than the forces binding the particles to the surface. Electrostatic lofting has been hypothesized to occur on the Moon and observed in the laboratory environment. Because gravity is much weaker on asteroids than on the Moon, the hypothesis of electrostatic lofting has naturally been extended to these smaller airless bodies. We evaluate the feasibility of electrostatic lofting on Bennu using two formulations of the patched charge model. We find that submillimeter particles can be lofted from Bennu’s dayside and, depending on their initial conditions, will reimpact or escape. The size and speed of the predicted electrostatically lofted particles are compared to those of the particle ejection events recently observed on Bennu. We find that dayside electrostatic lofting is not consistent with the size and speed of particles in the largest ejection events observed by the OSIRIS-REx mission. However, the escape of submillimeter particles has implications for the particle size distribution on Bennu’s surface. Additionally, we model particle charging on Bennu’s nightside due to secondary electron emission and find the resulting electrostatic force to be too weak to produce electrostatic lofting on the nightside. © 2022. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Photoelectric charging and lofting of dust particles on a conducting surface with external electric fields
No full textWe present a laboratory study of photoelectric charging of dust particles and their lofting on a conducting surface in the presence of external electric fields. Insulating particles with diameter <45 μm are dispersed on a conducting surface exposed to ultraviolet (UV) light. In addition to the UV exposure, a positive or negative external electric field is applied. Independent of the orientation of the external electric field, the dust particles are found to be positively charged but with different mechanisms. It is shown that the orientation of the external electric field controls the dynamics of photoelectrons emitted from the dust particles and the conducting substrate surface. Distinctly different lofting results are shown between these two electric field cases. The results provide insight for understanding dust charging and release and helping develop mitigation solutions in particle accelerators, semiconductor manufacturing, fusion reactors, and space exploration to planetary bodies
Fantastic story by Hugh Lofting
No full textBritanski književnik Hugh Lofting (1886. – 1947.) autor je serije popularnih priča o neobičnom doktoru Dolittleu koji razumije jezik životinja. Loftingova je fantastika posebne vrste: izrasla na ljubavi prema životinjama, iz iskustva s ratišta 1. svjetskog rata i iz otpora prema ratnim stradanjima ljudi i životinja. Cilj je rada književnoteorijskom analizom utvrditi karakteristike fantastičnih priča Hugha Loftinga, prisutne u serijalu priča o doktoru Dolittleu te njihovu primjerenost u radu s djecom mlađe školske dobi. Rezultati analiza u ovome radu ističu kako je najčešći pomak u irealno, u pričama Hugha Loftinga, upravo sposobnost doktora Dolittlea da razumije jezik kojim se životinje sporazumijevaju. Nadalje, rezultati također ukazuju kako Loftingove priče zadovoljavaju formu fantastične priče sadržavajući pomak u irealno, fantastična bića i fantastične događaje kao glavne elemente fantastičnih priča. Također, jedan od zaključaka je i taj da se Loftingove priče ističu prožetošću poučnim opisima, koji su proizašli iz autorove motivacije i stava da se prema životinjama treba odnositi, kao i prema ljudima, s poštovanjem i humanošću.British writer Hugh Lofting (1886. – 1947.) is the author of a series of popular stories about the unusual Doctor Dolittle who understands the language of animals. Lofting's fiction is of a special kind: it grew out of love for animals, from experience on the battlefields of World War I and from resistance to the wartime suffering of people and animals. The aim of the work is to determine the characteristics of Hugh Lofting's fantastic stories, present in the series of stories about Doctor Dolittle, and their appropriateness in work with younger school-age children through a literary-theoretical analysis. The results of the analyses in this paper point out that the most common shift to the unreal in Hugh Lofting's stories is precisely Doctor Dolittle's ability to understand the language used by animals to communicate. Furthermore, the results also indicate that Lofting's stories satisfy the fantasy story form by containing a shift into the unreal, fantastic beings and fantastic events as the main elements of fantasy stories. Also, one of the conclusions is that Lofting's stories stand out for being imbued with instructive descriptions, which arose from the author's motivation and attitude that animals should be treated, as well as people, with respect and humanity
Fantastic story by Hugh Lofting
No full textBritanski književnik Hugh Lofting (1886. – 1947.) autor je serije popularnih priča o neobičnom doktoru Dolittleu koji razumije jezik životinja. Loftingova je fantastika posebne vrste: izrasla na ljubavi prema životinjama, iz iskustva s ratišta 1. svjetskog rata i iz otpora prema ratnim stradanjima ljudi i životinja. Cilj je rada književnoteorijskom analizom utvrditi karakteristike fantastičnih priča Hugha Loftinga, prisutne u serijalu priča o doktoru Dolittleu te njihovu primjerenost u radu s djecom mlađe školske dobi. Rezultati analiza u ovome radu ističu kako je najčešći pomak u irealno, u pričama Hugha Loftinga, upravo sposobnost doktora Dolittlea da razumije jezik kojim se životinje sporazumijevaju. Nadalje, rezultati također ukazuju kako Loftingove priče zadovoljavaju formu fantastične priče sadržavajući pomak u irealno, fantastična bića i fantastične događaje kao glavne elemente fantastičnih priča. Također, jedan od zaključaka je i taj da se Loftingove priče ističu prožetošću poučnim opisima, koji su proizašli iz autorove motivacije i stava da se prema životinjama treba odnositi, kao i prema ljudima, s poštovanjem i humanošću.British writer Hugh Lofting (1886. – 1947.) is the author of a series of popular stories about the unusual Doctor Dolittle who understands the language of animals. Lofting's fiction is of a special kind: it grew out of love for animals, from experience on the battlefields of World War I and from resistance to the wartime suffering of people and animals. The aim of the work is to determine the characteristics of Hugh Lofting's fantastic stories, present in the series of stories about Doctor Dolittle, and their appropriateness in work with younger school-age children through a literary-theoretical analysis. The results of the analyses in this paper point out that the most common shift to the unreal in Hugh Lofting's stories is precisely Doctor Dolittle's ability to understand the language used by animals to communicate. Furthermore, the results also indicate that Lofting's stories satisfy the fantasy story form by containing a shift into the unreal, fantastic beings and fantastic events as the main elements of fantasy stories. Also, one of the conclusions is that Lofting's stories stand out for being imbued with instructive descriptions, which arose from the author's motivation and attitude that animals should be treated, as well as people, with respect and humanity
Fantastic story by Hugh Lofting
No full textBritanski književnik Hugh Lofting (1886. – 1947.) autor je serije popularnih priča o neobičnom doktoru Dolittleu koji razumije jezik životinja. Loftingova je fantastika posebne vrste: izrasla na ljubavi prema životinjama, iz iskustva s ratišta 1. svjetskog rata i iz otpora prema ratnim stradanjima ljudi i životinja. Cilj je rada književnoteorijskom analizom utvrditi karakteristike fantastičnih priča Hugha Loftinga, prisutne u serijalu priča o doktoru Dolittleu te njihovu primjerenost u radu s djecom mlađe školske dobi. Rezultati analiza u ovome radu ističu kako je najčešći pomak u irealno, u pričama Hugha Loftinga, upravo sposobnost doktora Dolittlea da razumije jezik kojim se životinje sporazumijevaju. Nadalje, rezultati također ukazuju kako Loftingove priče zadovoljavaju formu fantastične priče sadržavajući pomak u irealno, fantastična bića i fantastične događaje kao glavne elemente fantastičnih priča. Također, jedan od zaključaka je i taj da se Loftingove priče ističu prožetošću poučnim opisima, koji su proizašli iz autorove motivacije i stava da se prema životinjama treba odnositi, kao i prema ljudima, s poštovanjem i humanošću.British writer Hugh Lofting (1886. – 1947.) is the author of a series of popular stories about the unusual Doctor Dolittle who understands the language of animals. Lofting's fiction is of a special kind: it grew out of love for animals, from experience on the battlefields of World War I and from resistance to the wartime suffering of people and animals. The aim of the work is to determine the characteristics of Hugh Lofting's fantastic stories, present in the series of stories about Doctor Dolittle, and their appropriateness in work with younger school-age children through a literary-theoretical analysis. The results of the analyses in this paper point out that the most common shift to the unreal in Hugh Lofting's stories is precisely Doctor Dolittle's ability to understand the language used by animals to communicate. Furthermore, the results also indicate that Lofting's stories satisfy the fantasy story form by containing a shift into the unreal, fantastic beings and fantastic events as the main elements of fantasy stories. Also, one of the conclusions is that Lofting's stories stand out for being imbued with instructive descriptions, which arose from the author's motivation and attitude that animals should be treated, as well as people, with respect and humanity
Gyerekkirályfiak, beszélő állatok, csodálatos doktorok - életreform és gyermekirodalom
No full textThe author compares tree epic fairy tales born in the first thirty years of the 20th century (Lofting, Korczak,Béla Balázs), proving that the main motives are in direct relationship with the concept of children and societycoined with the life-reform movements and reformpedagogy of this period.A szerző három meseregényt hasonlít össze, melyek a XX. század első harmadában születtek (Lofting,Korczak, Balázs Béla), s kimutatja rokonságukat az életreformmozgalmak es reformpedagógiák gyermek- esemberképével
054 - Jennie Bukowski
No full textAirborne mineral dust has dilatant influences on the atmosphere and local environment: dust aerosols function as cloud condensation and ice nuclei, interact with radiation, fertilize maritime ecosystems, and are harmful to the human respiratory system. In arid regions, dust storms can loft an enormous amount of dust particles into the atmosphere and reduce visibility to near zero. In particular, the Arabian Peninsula reports frequent severe dust outbreaks as a result of strong surface winds, forced either by synoptic dynamics or mesoscale downdrafts, known as haboobs. Current forecast and climate models are run at high enough resolution to simulate synoptic events but still employ convective parameterizations, which are incapable of resolving many mesoscale processes. As such, the prediction of dust storms, specifically the location and timing of haboobs, remains a significant forecasting challenge. To understand the uncertainty introduced in the location and concentration of mineral dust via the use of convective parameterizations, the ratio of convective to non-convective dust events must first be established.
This study seeks to identify the origins of regional dust events across the Arabian Peninsula and quantify the relative contributions of synoptic versus mesoscale dust lofting. Here, the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) is used to simulate a 2016 summertime dust outbreak over the Arabian Peninsula. Several coarse grid simulations with various convective parameterizations are compared against the same runs with the convective parameterizations turned off, leaving only synoptic sources of dust lofting. These results are then contrasted against a fine grid simulation with resolved convection. For simulations including convection, the inception of individual dust plumes is separated into convective and non-convective source categories. Dust concentrations based on origin are then analyzed with respect to total domain dust abundance as well as horizontal and vertical extent. Results suggest that convective dust lofting over the Arabian Peninsula is a substantial source of dust to the atmosphere, and concentrations differ between simulations with convective parameterizations and those explicitly resolving convection
Mineral dust lofting and interactions with cold pools
No full text2021 Spring.Includes bibliographical references.Convective dust storms, or haboobs, form when strong surface winds loft loose soils in convective storm outflow boundaries. Haboobs are a public safety hazard and can cause a near instantaneous loss of visibility, inimical air quality, and contribute significantly to regional dust and radiation budgets. Nevertheless, reliable predictions of convective dust events are inhibited by a lack of understanding regarding the complex and non-linear interactions between cold pools, dust radiative effects, and land surface processes, and their associated uncertainties in numerical models. In this dissertation, model simulations of real and idealized haboobs are used to address limitations in regional dust modeling, the direct radiative effect of mineral dust on cold pool properties and dynamics, and feedbacks between haboobs and the land surface. In the first study, we assess the influence of horizontal resolution, specifically parameterized versus convection-allowing resolution, on dust lofting, vertical transport, and aerosol heating rates in the WRF-Chem regional model. On average, convection-permitting simulations exhibit higher surface wind speeds, enhanced convective activity, and drier soil, which leads to more dust emissions to the atmosphere. More frequent and stronger vertical velocities also transport dust further aloft and increase the atmospheric lifetime of these particles. We conclude that tuning dust emissions in coarse-resolution regional simulations can only improve the results to first-order and cannot fully rectify discrepancies in the representation of convective dust transport in terms of aerosol distributions or the net aerosol radiative effect. The second study, WRF-Chem is utilized to simulate the effect dust radiation interactions have on a long-lived haboob case study that spans three distinct radiative regimes: day (high shortwave), evening (low shortwave), and night (longwave only). A sophisticated algorithm, known as TOBAC, is used to track and identify the numerous cold pool boundaries and assemble statistics that represent the impact of including dust radiative effects. To first order, dust scattering of shortwave radiation in the day leads to a colder, dustier, and faster moving cold pool. In the transition period of early evening, the shortwave effects diminish while longwave absorption by dust leads to warmer and slower cold pools that loft less dust as they propagate onward. At night, the haboob is again warmer due to dust absorption, but gustier in the more stable nocturnal surface layer. Lastly, the third study focuses on feedbacks between parameters that affect both dust mobilization and cold pool dynamics. The Elementary Effects statistical method is applied to an ensemble of 120 idealized RAMS simulations of daytime and nighttime haboobs. This sensitivity analysis identifies and ranks the importance of different input factors in predicting haboob properties as: initial cold pool temperature, surface type, soil type, and finally soil moisture. Most of these parameters modify the cold pool via their impacts on surface fluxes, although the effect of surface type is dominated by the change in roughness length. A semi-linear connection between haboob dust and cold pool temperature is detected in the statistics, and a relationship between dust flux and cold pool temperature is proposed which relates haboob strength to the thermodynamic environment
Onomatopoeia Analysis on Doctor Dolittle Novel
No full textThis study deals with onomatopoeia in Doctor Dolittle novel by Hugh Lofting. The
objectives of the study were to analyze the types of onomatopoeia that used in the
Doctor Dolittle novel by Hugh Lofting, to analyze why onomatopoeia used in Doctor
Dolittle novel by Hugh Lofting, and to investigate how the author describe the
onomatopoeia word in his novel. The scope and limitation were focused about
onomatopoeia words found in the Doctor Dolittle novel by Hugh Lofting. The
researcher analyzed three types of onomatopoeia, there are Direct Onomatopoeia,
Associative Onomatopoeia, and Exemplary Onomatopoeia. This study applied a
descriptive qualitative method and it was taken place in library of UMSU to analyze
the data. The data of this reseach was taken from the Doctor Dolittle novel. were the
novel The technique of data analyzing was from the data collection, data
presentation, data verification and, data reduction. The research finding showed that
there were 38 of onomatopoeia found in this research which consist of 7 words direct
onomatopoeia, 24 words assiciative onomatopoeia, and 7 exemplary onomatopoeia
based on Bredin's (1996 : 558). Associative Onomatopoeia was the dominant types
of Doctor Dolittle novel by Hugh Lofting
Orbital motion of regolith around asteroids
No full textWe study the orbital motion of regolith around asteroids, lofted from the surface due to impact cratering events, to understand the displacement of material on the surface and in orbit. The cratering events could be natural such as from meteoroid impacts, or they can be induced from spacecraft activities such as in-situ sample collection. Understanding the dynamics of orbiting regolith is important for future science missions and commercial activities on asteroids. Knowledge about expected particulate environment due to impact ejecta can help mission designers in trajectory planning to avoid interference or damage from orbiting regolith with a spacecraft and/or its instruments. The same study could be exploited in the field of commercial in-situ asteroid mining for sorting material of different sizes and densities by artificially lofting them into an orbit...Aerospace Engineerin
