1,592 research outputs found
Investigating the rheological properties and compatibility behaviours of RET/PE and WR/CR/ SBS compound-modified bitumen
No full textTwo types of elastomer/plastic compound-modified bitumen were developed by means of incorporating the reactive elastomeric terpolymer (RET) into the plastic (high-density polyethylene HDPE or recycled polyethylene RPE) modified bitumen and adding the wax residue (WR) into the bitumen/elastomer (crumb rubber CR or styrene–butadiene–styrene SBS) blends. The rheological properties, morphology microstructure and storage stability of these novel elastomer/plastic compound-modified binders were characterised. The results revealed that RET elastomer positively improved the high-temperature modulus, temperature insensitivity, rut resistant, elastic recovery and shear-resistance of HDPE- and RPE-modified bitumen. However, excessive RET dosage adversely influenced the cracking resistance of plastic-modified bitumen, and its optimum dosage was recommended as 1 wt%. Moreover, RET elastomer significantly strengthened the storage stability of HDPE and RPE-modified binders. The elasticity improvement effect of RET was attributed to the generated polymer network. On the other hand, adding WR limitedly deteriorated the rutting resistance and weakened the elastic recovery performance of elastomer (CR and SBS) modified bitumen. To ensure the low-temperature performance, the optimum level of WR was 2 wt%. Furthermore, the addition of WR promoted the compatibility and dispersion of CR and SBS modifiers in bitumen.Pavement Engineerin
WR 280 Practicum Report: Wildlife Management Techniques
No full textWildland RecreationAs part of the Wildland Recreation Spring Practicum, the author worked at the Fort St. John Fish and Wildlife Branch of the Ministry of Environment and Parks for two weeks, under the supervision of Rob Woods, Habitat Protection Technician. The author's volunteer work gave him an understanding of wildlife management techniques that included radio telemetry, classified counts, and ungulate aging/Harvest Cards
Vrist - brist - rist : Development of old initial wr in Scandinavian, particularly Swedish, dialects
No full textThe Germanic initial sound combination wr (e.g. in *wrītan 'write') has not been preserved in any standard language. In the Scandinavian languages the development of this sound combination has resulted in five different initial sounds or sound combinations, namely rw, r, w, br and vr. The aim of this study is to describe the occurrence of these sound combinations, and to explain their age and origin. A limited number of words, mainly from Swedish dialects, has been investigated. The Swedish material has been assembled in a collection that has largely also been mapped, and so has a collection of Norwegian dialect material. The result shows that br is frequent in the Swedish dialects and that it also occurs in Trøndelagen and Østlandet in Norway, and on Jutland. R is widespread in Norway and occurs in Sweden in some words in Norrland, Dalarna, Värmland, Dalsland, Uppland and on the island of Gotland. Rw has been documented in Upper Dalarna, and w in the same area, as well as in the Kalix dialect in northernmost Sweden. The author demonstrates that the Norwegian loss of w might have started already in the 6th century in western Norway. The loss on Gotland is independent and can be demonstrated in Old Gutnish. The metathesis rw is found in Swedish and Norwegian 13-14th century sources from Uppland, Västmanland, Östergötland and southeastern Norway. The developments wr > r and wr > rw probably have their roots in a difference between the west Norwegian wr and the east Norwegian and Swedish war which is documented from PrimScand times. W is a secondary development of rw. The change wr > br can be dated by place-name material to the early 15th century. The change wr > vr appears to have taken place at approximately the same time. The author demonstrates that the result, wr > br or wr > yr, is apparently governed by certain phonetic factors. The failure of the Germanic wr to survive depends on the combination being phonetically complex. The risk that w would be lost was therefore considerable. However, differentiating forces worked for its retention. All developments emanating from wr, apparently disparate, can be seen as features of a larger process where a general linguistic tendency towards a weakening of sounds is confronted by conservative forces, with the above results as a consequence.Doktorsavhandling vid Uppsala universitet 1991</p
Dynamic Imprints of Colliding-wind Dust Formation from WR 140
No full textCarbon-rich Wolf-Rayet (WR) binaries are a prominent source of carbonaceous dust that contribute to the dust budget of galaxies. The “textbook” example of an episodic dust-producing WR binary, WR 140 (HD 193793), provides us with an ideal laboratory for investigating the dust physics and kinematics in an extreme environment. This study is among the first to utilize two separate JWST observations, from Cycle 1 ERS (2022 July) and Cycle 2 (2023 September), to measure WR 140’s dust kinematics and confirm its morphology. To measure the proper motions and projected velocities of the dust shells, we performed a novel point-spread function (PSF) subtraction to reduce the effects of the bright diffraction spikes and carefully aligned the Cycle 2 to the Cycle 1 images. At 7.7 μm, through the bright feature common to 16 dust shells (C1), we find an average dust shell proper motion of 390 ± 29 mas yr−1, which equates to a projected velocity of 2714 ± 188 km s−1 at a distance of 1.64 kpc. Our measured speeds are constant across all visible shells and consistent with previously reported dust expansion velocities. Our observations not only prove that these dusty shells are astrophysical (i.e., not associated with any PSF artifact) and originate from WR 140, but also confirm the “clumpy” morphology of the dust shells, in which identifiable substructures within certain shells persist for at least 14 months from one cycle to the next. These results support the hypothesis that clumping in the wind collision region is required for dust production in WR binaries
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The orbit and stellar masses of the archetype colliding-wind binary WR 140
No full textWe present updated orbital elements for the Wolf-Rayet (WR) binary WR 140 (HD 193793; WC7pd + O5.5fc). The new orbital elements were derived using previously published measurements along with 160 new radial velocity measurements across the 2016 periastron passage of WR 140. Additionally, four new measurements of the orbital astrometry were collected with the CHARA Array. With these measurements, we derive stellar masses of and . We also include a discussion of the evolutionary history of this system from the Binary Population and Spectral Synthesis model grid to show that this WR star likely formed primarily through mass-loss in the stellar winds, with only a moderate amount of mass lost or transferred through binary interactions. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.Immediate accessThis 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]
Vrist - brist - rist [Elektronisk resurs] : Utvecklingen av gammalt uddljudande <em>wr</em> i nordiska, särskilt svenska, dialekter
No full textThe Germanic initial sound combination wr (e.g. in *wrītan 'write') has not been preserved in any standard language. In the Scandinavian languages the development of this sound combination has resulted in five different initial sounds or sound combinations, namely rw, r, w, br and vr.The aim of this study is to describe the occurrence of these sound combinations, and to explain their age and origin. A limited number of words, mainly from Swedish dialects, has been investigated. The Swedish material has been assembled in a collection that has largely also been mapped, and so has a collection of Norwegian dialect material.The result shows that br is frequent in the Swedish dialects and that it also occurs in Trøndelagen and Østlandet in Norway, and on Jutland. R is widespread in Norway and occurs in Sweden in some words in Norrland, Dalarna, Värmland, Dalsland, Uppland and on the island of Gotland. Rw has been documented in Upper Dalarna, and w in the same area, as well as in the Kalix dialect in northernmost Sweden.The author demonstrates that the Norwegian loss of w might have started already in the 6th century in western Norway. The loss on Gotland is independent and can be demonstrated in Old Gutnish. The metathesis rw is found in Swedish and Norwegian 13-14th century sources from Uppland, Västmanland, Östergötland and southeastern Norway. The developments wr > r and wr > rw probably have their roots in a difference between the west Norwegian wr and the east Norwegian and Swedish war which is documented from PrimScand times. W is a secondary development of rw. The change wr > br can be dated by place-name material to the early 15th century. The change wr > vr appears to have taken place at approximately the same time. The author demonstrates that the result, wr > br or wr > yr, is apparently governed by certain phonetic factors.The failure of the Germanic wr to survive depends on the combination being phonetically complex. The risk that w would be lost was therefore considerable. However, differentiating forces worked for its retention. All developments emanating from wr, apparently disparate, can be seen as features of a larger process where a general linguistic tendency towards a weakening of sounds is confronted by conservative forces, with the above results as a consequence.</p
Dynamic Imprints of Colliding-wind Dust Formation from WR 140
No full textThis article was originally published in The Astrophysical Journal Letters. The version of record is available at: https://doi.org/10.3847/2041-8213/ad9aa9.
© 2025. The Author(s). Published by the American Astronomical Society.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence (https://creativecommons.org/licenses/by/4.0/). Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Carbon-rich Wolf–Rayet (WR) binaries are a prominent source of carbonaceous dust that contribute to the dust budget of galaxies. The "textbook" example of an episodic dust-producing WR binary, WR 140 (HD 193793), provides us with an ideal laboratory for investigating the dust physics and kinematics in an extreme environment. This study is among the first to utilize two separate JWST observations, from Cycle 1 ERS (2022 July) and Cycle 2 (2023 September), to measure WR 140's dust kinematics and confirm its morphology. To measure the proper motions and projected velocities of the dust shells, we performed a novel point-spread function (PSF) subtraction to reduce the effects of the bright diffraction spikes and carefully aligned the Cycle 2 to the Cycle 1 images. At 7.7 μm, through the bright feature common to 16 dust shells (C1), we find an average dust shell proper motion of 390 ± 29 mas yr−1, which equates to a projected velocity of 2714 ± 188 km s−1 at a distance of 1.64 kpc. Our measured speeds are constant across all visible shells and consistent with previously reported dust expansion velocities. Our observations not only prove that these dusty shells are astrophysical (i.e., not associated with any PSF artifact) and originate from WR 140, but also confirm the "clumpy" morphology of the dust shells, in which identifiable substructures within certain shells persist for at least 14 months from one cycle to the next. These results support the hypothesis that clumping in the wind collision region is required for dust production in WR binaries.The work of E.P.L. is supported by NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the U.S. National Science Foundation. J.L.H. acknowledges support from the National Science Foundation under award AST-1816944. T.O. acknowledges support by the Japan Society for the Promotion of Science (JSPS) KAKENHI grant No. JP24K07087. N.D.R. is grateful for support from the Cottrell Scholar Award #CS-CSA-2023-143 sponsored by the Research Corporation for Science Advancement. J.S.-B. acknowledges the support received from the UNAM PAPIIT project IA 105023. C.M.P.R. acknowledges support from NASA Chandra Theory grant TM3-24001X. This material is based upon work supported by NASA under award number 80GSFC24M0006 and based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract number NAS 5-03127 for JWST. These observations are associated with programs #3823 and #1349. Support for program #3823 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. We thank the anonymous reviewer for insightful feedback that improved the quality of this manuscript. We thank Christopher Packham and Mason Leist for their valuable discussions about the MIRI PSF subtraction
Data protection: the challenges facing social networking
No full textThe popularity of social networking sites has increased dramatically over the past decade. A recent report indicated that thirty-eight percent of online users have a social networking profile. Many of these social networking site users (SNS users) post or provide personal information over the internet every day. According to the latest OfCom study, the average adult SNS user has profiles on 1.6 sites and most check their profiles at least once every other day. However, the recent rise in social networking activity has opened the door to the misuse and abuse of personal information through identity theft, cyber stalking, and undesirable screenings by prospective employers. Behavioral advertising programs have also misused personal information available on social networking sites. Society is now facing an important question: what level of privacy should be expected and required within the social networking environment
Real Exchange Rate in China : A Long-run Perspective
No full textThis paper investigates the RMB exchange rate from a long-run viewpoint. Whether Chinas rapid economic growth brought about real exchange rate appreciation between 1975 and 2002 is empirically examined, based on a supply-side model, the BalassaSemuelson Hypothesis (BSH). The same test is conducted on Japan, Hong Kong, Korea, Malaysia, Singapore, Thailand, the Philippines, Indonesia and India. Our result indicates that the BSH only exists where the industrial structure has been upgraded and the economy has been successfully transformed from an agricultural economy to a manufacturing economy. Interestingly, China, among those where the BSH does not present, appears to be upgrading its industrial and trade structure. We then try to answer the question of why past rapid growth has no significant relationship with the RMB real exchange rate and what factors are underlying the trend of the RMB real exchange rate. We expect an appreciating trend of RMB real exchange rate in the foreseeable future, presuming that Chinas industrial upgrading process continues and the factors pertaining to the BSHs prediction, such as rise of wage rates in both tradables and nontradables, become more significant.RMB real exchange rate, economic growth
Modes in Algol Y
No full textIt recently appeared to the author that the semantics of recursively
defined data-types (from now on the term circularly defined data-types
will be used to keep away from the "recursive function theory" connotation
of the adjective "recursive") could benefit largely from the bulk of
recent work on domain equations initiated by Dana Scott
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