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Journal articles on the topic 'Fragmentation upon impact'

Author: Grafiati

Published: 4 June 2021

Last updated: 9 February 2022

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1

Victorov, S. D., A. N. Kochanov, and V. N. Odintsev. "Fragmentation of Coal Samples upon Intense Dynamic Impact." Bulletin of the Russian Academy of Sciences: Physics 83, no. 6 (June 2019): 673–76. http://dx.doi.org/10.3103/s1062873819060376.

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2

Rontani, J. F., and C. Aubert. "Fragmentation of 1-phenyl-2-alkylcyclobutanols upon electron impact." Organic Mass Spectrometry 28, no. 7 (July 1993): 795–96. http://dx.doi.org/10.1002/oms.1210280713.

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3

Vais, V., and A. Mandelbaum. "Stereospecific Fragmentation of 3-Dimethylaminocyclohexanols upon Electron Impact Ionization." Journal of Mass Spectrometry 32, no. 7 (July 1997): 750–54. http://dx.doi.org/10.1002/(sici)1096-9888(199707)32:7<750::aid-jms527>3.0.co;2-y.

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4

Guccione, Davide Ettore, Klaus Thoeni, Stephen Fityus, François Nader, Anna Giacomini, and Olivier Buzzi. "An Experimental Setup to Study the Fragmentation of Rocks Upon Impact." Rock Mechanics and Rock Engineering 54, no. 8 (June 5, 2021): 4201–23. http://dx.doi.org/10.1007/s00603-021-02501-3.

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5

Golosov, Grigorii V., and Kirill Kalinin. "Presidentialism and legislative fragmentation: Beyond coattail effects." British Journal of Politics and International Relations 19, no. 1 (December 19, 2016): 113–33. http://dx.doi.org/10.1177/1369148116682654.

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Using data from a nearly comprehensive set of the world’s electoral democracies, 1992–2014, this article empirically evaluates the impact of presidentialism upon legislative fragmentation. The analysis demonstrates that the impact is strong, consistent across a wide variety of political contexts, and conditioned by the type of presidential regime, the scope of presidential powers, electoral system effects, and essential party system properties. While much of the reasoning regarding the interplay between presidentialism and legislative fragmentation has been traditionally focused on short-term coattail effects of presidential elections, this study shows that these effects are real, but they are insufficient to make a significant impact upon the parameter of crucial importance for the functioning of presidential regimes: the number of parties in the legislature. The main impact of presidentialism is systemic, stemming from its tendency to restrict the number of parties to a limited set of viable competitors for the presidential prize.

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6

Herrmann, Michael, and Gerhard W. Fischer. "Fragmentation of 1-aryl-5-(2-dialkylaminovinyl)-1H-tetrazoles upon electron impact." Organic Mass Spectrometry 24, no. 9 (September 1989): 823–29. http://dx.doi.org/10.1002/oms.1210240917.

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7

Medina-Franco, José Luis, Cecilia Juárez-Gordiano, Alicia Hernández-Campos, Georgina Duarte-Lisci, Margarita Guzmán, and Rafael Castillo. "New fragmentation processes of pyridin-2(1H)-ones upon electron impact ionization." Rapid Communications in Mass Spectrometry 19, no. 16 (2005): 2350–54. http://dx.doi.org/10.1002/rcm.2059.

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8

Ye, Yang, Klaus Thoeni, Yawu Zeng, Olivier Buzzi, and Anna Giacomini. "Numerical Investigation of the Fragmentation Process in Marble Spheres Upon Dynamic Impact." Rock Mechanics and Rock Engineering 53, no. 3 (September 30, 2019): 1287–304. http://dx.doi.org/10.1007/s00603-019-01972-9.

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9

Wang, Yuannian, and Fulvio Tonon. "Discrete Element Modeling of Rock Fragmentation upon Impact in Rock Fall Analysis." Rock Mechanics and Rock Engineering 44, no. 1 (July 27, 2010): 23–35. http://dx.doi.org/10.1007/s00603-010-0110-9.

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10

Sekiguchi, Osamu, Toshiyuki Kosaka, Takeshi Kinoshita, and Susumu Tajima. "Fragmentation of organosulfur compounds upon electron impact: 2-mercaptoethanol and 1,2-ethanedithiol." International Journal of Mass Spectrometry and Ion Processes 145, no. 1-2 (July 1995): 25–33. http://dx.doi.org/10.1016/0168-1176(95)04165-h.

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11

Mastilovic, Sreten. "Damage-fragmentation transition: Size effect and scaling behavior for impact fragmentation of slender projectiles." International Journal of Damage Mechanics 27, no. 2 (September 25, 2016): 201–17. http://dx.doi.org/10.1177/1056789516671775.

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The focus of the present article is on the size effect of a transition region from the damaged to the fragmented phase in impact-induced breakup of a slender projectile. Molecular dynamics simulations of the classic ballistic Taylor test are performed with a simple generic model to explore an extended low-energy range. In the simulation setup, flat-ended, monocrystalline, nanoscale projectiles, with a fixed aspect ratio but 10 different diameters, collide perpendicularly with a rough rigid wall. With gradually increasing impact energy, a non-negligible projectile disintegration eventually takes place and is identified with the damage-fragmentation phase transition. These atomistic simulations offer an indispensable tool to gain an insight into damage evolution in the neighborhood of the damage-fragmentation transition resulting in the occurrence of fragmentation at the critical point. A finite size scaling analysis of the average fragment mass is carried out to determine critical exponents and dependence of the critical striking velocity upon the slender projectile’s diameter.

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12

Halberstadt, Nadine, and David A. Bonhommeau. "Fragmentation dynamics of Ar4He1000 upon electron impact ionization: Competition between ion ejection and trapping." Journal of Chemical Physics 152, no. 23 (June 21, 2020): 234305. http://dx.doi.org/10.1063/5.0009363.

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13

Vetter, Walter, Walter Meister, and Gottfried Oesterhelt. "2-Alkylimidazoline derivative to control fatty acid fragmentation upon electron impact and electrospray ionization." Journal of Mass Spectrometry 33, no. 5 (May 1998): 461–72. http://dx.doi.org/10.1002/(sici)1096-9888(199805)33:5<461::aid-jms656>3.0.co;2-3.

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14

Verreault, Jimmy. "Analytical and numerical description of the PELE fragmentation upon impact with thin target plates." International Journal of Impact Engineering 76 (February 2015): 196–206. http://dx.doi.org/10.1016/j.ijimpeng.2014.09.012.

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15

Castleman, A. W., and Bruce D. Kay. "Evidence for the fragmentation of clusters upon electron impact ionization from electric deflection experiments." International Journal of Mass Spectrometry and Ion Processes 66, no. 2 (July 1985): 217–22. http://dx.doi.org/10.1016/0168-1176(85)83011-1.

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16

Wang, Y., and L. Bourouiba. "Non-isolated drop impact on surfaces." Journal of Fluid Mechanics 835 (November 27, 2017): 24–44. http://dx.doi.org/10.1017/jfm.2017.755.

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Upon impact on a solid surface, a drop expands into a sheet, a corona, which can rebound, stick or splash and fragment into secondary droplets. Previously, focus has been placed on impacts of single drops on surfaces to understand their splash, rebound or spreading. This is important for spraying, printing, and environmental and health processes such as contamination by pathogen-bearing droplets. However, sessile drops are ubiquitous on most surfaces and their interaction with the impacting drop is largely unknown. We report on the regimes of interactions between an impacting drop and a sessile drop. Combining experiments and theory, we derive the existence conditions for the four regimes of drop–drop interaction identified, and report that a subtle combination of geometry and momentum transfer determines a critical impact force governing their physics. Crescent-moon fragmentation is most efficient at producing and projecting secondary droplets, even when the impacting drop Weber number would not allow for splash to occur on the surface considered if the drop were isolated. We introduce a critical horizontal impact Weber number $We_{c}$ that governs the formation of a sheet from the sessile drop upon collision with the expanding corona of the impacting drop. We also predict and validate important properties of the crescent-moon fragmentation: the extension of its sheet base and the ligaments surrounding its base. Finally, our results suggest a new paradigm: impacts on most surfaces can make a splash of a new kind – a crescent-moon – for any impact velocity when neighbouring sessile drops are present.

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17

Planchette, C., E. Lorenceau, and G. Brenn. "The onset of fragmentation in binary liquid drop collisions." Journal of Fluid Mechanics 702 (May 1, 2012): 5–25. http://dx.doi.org/10.1017/jfm.2012.94.

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AbstractBinary collisions of drops of immiscible liquids are investigated experimentally at well-defined conditions of impact. In the experiments we vary all relevant properties of an aqueous and an oil phase, the impact parameter, the drop size and the relative velocity. The drops observed after the collisions exhibit three main phenomena: full encapsulation, head-on fragmentation, and off-centre fragmentation. The regimes characterized by these phenomena replace the ones observed in binary collisions of drops of the same liquid: coalescence, reflexive separation, and stretching separation. Our aim is a universal description of the two fragmentation thresholds of such collisions. Based on the capillary instability and an energy balance, we establish for head-on collisions a scaling law for the evolution of the threshold impact velocity with the properties of the liquids and the droplet size. The fragmentation threshold for off-centre collisions is compared to established models from the literature, which appear unsatisfactory. Introducing an effective impact parameter, which accounts empirically for the deformation and rotation of the drops upon impact, we describe this fragmentation threshold in a universal way. For both fragmentation thresholds, the agreement between experimental data and their theoretical representation is very good. Our work yields new insight into binary collisions of drops and proposes a perspective to develop a more general description with implications for binary collisions of drops of a single liquid as well.

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18

SEKIGUCHI, Osamu, and Susumu TAJIMA. "Fragmentation of Organosulfur Compounds upon Electron Impact. II. Metastable Decomposition of Methyl and Ethyl Thiolactates." Journal of the Mass Spectrometry Society of Japan 44, no. 2 (1996): 211–18. http://dx.doi.org/10.5702/massspec.44.211.

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19

Myagkov, N. N. "Scaling invariance of spherical projectile fragmentation upon high-velocity impact on a thin continuous shield." Journal of Experimental and Theoretical Physics 124, no. 1 (January 2017): 57–69. http://dx.doi.org/10.1134/s1063776116150115.

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20

Ng, C. W. W., C. E. Choi, D. K. H. Cheung, and Y. Cui. "Effects of dynamic fragmentation on the impact force exerted on rigid barrier: centrifuge modelling." Canadian Geotechnical Journal 56, no. 9 (September 2019): 1215–24. http://dx.doi.org/10.1139/cgj-2018-0092.

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Bi-dispersity is a prerequisite for grain-size segregation, which transports the largest particles to the flow front. These large and inertial particles can fragment upon impacting a barrier. The amount of fragmentation during impact strongly influences the force exerted on a rigid barrier. Centrifuge modelling was adopted to replicate the stresses for studying the effects of bi-dispersity in a granular assembly and dynamic fragmentation on the impact force exerted on a model rigid barrier. To study the effects of bi-dispersity, the ratio between the diameters of small and large particles (δs/δl), characterizing the particle-size distribution (PSD), was varied as 0.08, 0.26, and 0.56. The volume fraction of the large particles was kept constant. A δs/δl tending towards unity characterizes inertial flow that exerts sharp impulses, and a diminishing δs/δl characterizes the progressive attenuation of these sharp impulses by the small particles. Flows dominated by grain-contact stresses (δs/δl < 0.26), as characterized by the Savage number, are effective at attenuating dispersive stresses of the large particles, which are responsible for reducing dynamic fragmentation. By contrast, flows dominated by grain-inertial stresses (δs/δl > 0.26) exhibit up to 66% more impulses and 4.3 times more fragmentation. Dynamic fragmentation of bi-disperse flows impacting a rigid barrier can dissipate about 30% of the total flow energy.

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21

Vasyukova, N. I., B. L. Tumanskii, B. N. Strunin, K. I. Grandberg, Yu S. Nekrasov, N. N. Bubnov, S. P. Solodovnikov, and A. I. Prokof'ev. "Fragmentation pathways of [(Ph3P)AuM(CO)3(n5-C5H4CHO)] upon electron impact in the gas phase or upon photolysis in solution." Bulletin of the Academy of Sciences of the USSR Division of Chemical Science 36, no. 12 (December 1987): 2504–9. http://dx.doi.org/10.1007/bf00957221.

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22

Swope, Nicole, Wai Keen Chung, Mingyan Cao, Dana Motabar, Dengfeng Liu, Sanjeev Ahuja, and Michael Handlogten. "Impact of enzymatic reduction on bivalent bispecific antibody fragmentation and loss of product purity upon reoxidation." Biotechnology and Bioengineering 117, no. 4 (January 23, 2020): 1063–71. http://dx.doi.org/10.1002/bit.27264.

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23

Szczepaniak, Walenty, and Adam S. Płaziak. "Mass spectrometry of dithiophophate metal complexes: Fragmentation of nickel(II) bis(diaryldithiophosphate) complexes upon electron impact." Organic Mass Spectrometry 20, no. 5 (May 1985): 379–81. http://dx.doi.org/10.1002/oms.1210200512.

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24

Szczepaniak, Walenty, and Adam S. Plaziak. "Mass spectrometry of dithiophosphate metal complexes: Fragmentation of thallium(I)O,O′-diaryldithiophosphates upon electron impact." Organic Mass Spectrometry 20, no. 12 (December 1985): 785–86. http://dx.doi.org/10.1002/oms.1210201218.

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25

Guccione, Davide Ettore, Olivier Buzzi, Klaus Thoeni, Stephen Fityus, and Anna Giacomini. "Predicting the fragmentation survival probability of brittle spheres upon impact from statistical distribution of material properties." International Journal of Rock Mechanics and Mining Sciences 142 (June 2021): 104768. http://dx.doi.org/10.1016/j.ijrmms.2021.104768.

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26

Guccione, D. E., K. Thoeni, A. Giacomini, O. Buzzi, and S. Fityus. "EFFICIENT MULTI-VIEW 3D TRACKING OF ARBITRARY ROCK FRAGMENTS UPON IMPACT." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 12, 2020): 589–96. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-589-2020.

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Abstract. This paper presents a new methodology to accurately obtain 3D rotational velocities of blocks and fragments. Four high speed cameras are used to capture the scene. An additional two tilted mirrors are used to multiply the number of views. Hence, a total of six different viewing perspectives can be used to track translational and rotational velocities in 3D. The focus in the current work is on the rotational velocities, as tracking of the translation is generally straightforward. A common outline tracking algorithm based on the visual hull is adapted. The visual hull is further meshed using triangular elements to approximate the shape of the object. This 3D reconstruction is then used to track the 3D motion of the object. However, the accuracy of the results strongly depends on the accuracy of the 3D reconstruction which is mainly influenced by the number and position of the available views. In any case, the 3D reconstruction from the visual hull is only an approximation and significant errors can be introduced which influence the tracking accuracy. Hence, an in-house post-processing algorithm based on the knowledge of the real geometry of the object, which can generally be accurately determined after a test, was developed. The improved performance of this new post-processing method is shown by controlled spinning tests. Finally, results of a real example of an impact fragmentation test are discussed.

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27

Wang, Y., and L. Bourouiba. "Unsteady sheet fragmentation: droplet sizes and speeds." Journal of Fluid Mechanics 848 (June 13, 2018): 946–67. http://dx.doi.org/10.1017/jfm.2018.359.

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Understanding what shapes the drop size distributions produced from fluid fragmentation is important for a range of industrial, natural and health processes. Gilet & Bourouiba (J. R. Soc. Interface, vol. 12, 2015, 20141092) showed that both the size and speed of fragmented droplets are critical to transmission of pathogens in the agricultural context. In this paper, we study both the size and speed distributions of droplets ejected during a canonical unsteady sheet fragmentation from drop impact on a target of comparable size to that of the drop. Upon impact, the drop transforms into a sheet which expands in the air bounded by a rim on which ligaments grow, continuously shedding droplets. We developed high-precision tracking algorithms that capture all ejected droplets, measuring their size and speed, as well as the detachment time from, and link to, their ligament of origin. Both size and speed distributions of all ejected droplets are skewed. We show that the polydispersity and skewness of the distributions are inherently due to the unsteadiness of the sheet expansion. We show that each ligament sheds a single drop at a time throughout the entire sheet expansion by a mechanism of end-pinching. The droplet-to-ligament size ratio $R\approx 1.5$ remains constant throughout the unsteady fragmentation, and is robust to change in impact Weber number. We also show that the population mean speed of the fragmented droplets at a given time is equal to the population mean speed of ligaments one necking time prior to detachment time.

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Nasielski-Hinkens, Raymonde, Michel Kaisin, Robert Flammang, and André Maquestiau. "Fragmentation of 1,4,5,8-tetraazaphenanthrenes upon electron impact: A new example of structural integrity of gas phase heteroaromatic cations." Organic Mass Spectrometry 20, no. 12 (December 1985): 733–37. http://dx.doi.org/10.1002/oms.1210201207.

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29

May, S. A., and T. W. Norton. "Influence of fragmentation and disturbance on the potential impact of feral predators on native fauna in Australian forest ecosystems." Wildlife Research 23, no. 4 (1996): 387. http://dx.doi.org/10.1071/wr9960387.

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The current knowledge is reviewed of the diet and predator–prey relationships of the feral cat (Felis catus), fox (Vulpes vulpes) and dingo (Canis familiaris dingo) (including wild dogs). The effect of forest fragmentation by roads on the use of native forest ecosystems by these species and the significance of this for native fauna is considered. The cat, fox and dingo are significant predators in Australia that interact with native fauna in various ways, including predation, competition for resources, and transmission of disease. On the basis of current knowledge, it is clear that the nature and impact of predation by the cat, fox and dingo on native fauna are primarily determined by prey availability, although there are exceptions to this rule. Generally, dingoes prey upon large to medium-sized prey species (e.g. wallabies, common wombats, and possums), foxes prey upon medium-sized to small prey (e.g. possums and rats) and consume a significant component of scavenged material and vegetation, while cats also prey upon medium-sized to small prey, but may have a greater proportion of reptiles and birds in their diet. The cat is generally considered to be an opportunistic predator and to have contributed to the demise of a number of mammals. The fox is considered more of a threat to small native mammals and it has been asserted that all species of mammals that fall within the critical weight range (CWR) of 120–5000 g are at risk of local extinction when the fox is present. The severity of the impact of the dingo upon the native fauna is considered to be minimal, at least in comparison with the impact that the cat and fox can have on populations. The dingo is not considered a threat to CWR mammals in undisturbed environments. The fox, feral cat and dingo are all considered to have the ability to selectivity prey upon species and, to some extent, individual sexes and age-classes of a number of larger prey species. Although many of Australia's forested areas are relatively heavily fragmented by roads, there are no published studies specifically investigating the use of roads by feral predators. Information on the distribution and abundance of foxes, cats and dingoes in these ecosystems, their ecology and their impact on native fauna is particularly limited. Further, the extent to which roads influence the distribution and abundance of these species and the consequences of these for native fauna are poorly known. One of the most important research needs is to establish the relative impact that exotic predators may have on native fauna under varying degrees of road construction within native forests. For example, are areas with and without roads in forests used differently by exotic predators and what is the significance of this in terms of the potential impact on fauna? The extent to which feral predators forage away from roads needs further investigation, as does the rates of predation within edges, because this may have several consequences for the design, location and size of retained strips and wildlife corridors as well as restoration programmes. Further observations on regional differences influencing predator–prey interactions are required, as is research on the potential impacts on native fauna resulting from prey selection in forests subjected to various degrees of fragmentation and modification.

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30

Krause, Simon, Volodymyr Bon, Hongchu Du, Rafal E. Dunin-Borkowski, Ulrich Stoeck, Irena Senkovska, and Stefan Kaskel. "The impact of crystal size and temperature on the adsorption-induced flexibility of the Zr-based metal–organic framework DUT-98." Beilstein Journal of Nanotechnology 10 (August 20, 2019): 1737–44. http://dx.doi.org/10.3762/bjnano.10.169.

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In this contribution we analyze the influence of adsorption cycling, crystal size, and temperature on the switching behavior of the flexible Zr-based metal–organic framework DUT-98. We observe a shift in the gate-opening pressure upon cycling of adsorption experiments for micrometer-sized crystals and assign this to a fragmentation of the crystals. In a series of samples, the average crystal size of DUT-98 crystals was varied from 120 µm to 50 nm and the obtained solids were characterized by X-ray diffraction, infrared spectroscopy, as well as scanning and transmission electron microscopy. We analyzed the adsorption behavior by nitrogen and water adsorption at 77 K and 298 K, respectively, and show that adsorption-induced flexibility is only observed for micrometer-sized crystals. Nanometer-sized crystals were found to exhibit reversible type I adsorption behavior upon adsorption of nitrogen and exhibit a crystal-size-dependent steep water uptake of up to 20 mmol g−1 at 0.5 p/p 0 with potential for water harvesting and heat pump applications. We furthermore investigate the temperature-induced structural transition by in situ powder X-ray diffraction. At temperatures beyond 110 °C, the open-pore state of the nanometer-sized DUT-98 crystals is found to irreversibly transform to a closed-pore state. The connection of crystal fragmentation upon adsorption cycling and the crystal size dependence of the adsorption-induced flexibility is an important finding for evaluation of these materials in future adsorption-based applications. This work thus extends the limited amount of studies on crystal size effects in flexible MOFs and hopefully motivates further investigations in this field.

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Завилопуло, А. Н., О. Б. Шпеник, and О. В. Пилипчинец. "Масс-спектрометрия молекулы ксилита." Журнал технической физики 89, no. 1 (2019): 16. http://dx.doi.org/10.21883/jtf.2019.01.46955.100-18.

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AbstractThe technique and results of a mass spectrometric study on the yield of positive ions formed upon ionization of xylitol molecules by electron impact are discussed. The mass spectra of xylitol are studied in the range of mass numbers of 10–160 Da and in the range of bombarding electrons energies of 5–80 eV. Based on the analysis of the measured mass spectra, a scheme of xylitol fragmentation is proposed, which contains the most probable channels of formation of ion-fragments upon electron impact, when the energy of the incident electrons significantly exceeds the ionization potential of the molecule. The appearance energies of ionized fragments of xylitol are determined for the first time from the energy dependences of the effective cross-section formation of the ions upon electron impact. The dynamics of ionized fragment formation is studied in the temperature range of the initial substance evaporation of 340–410 K. The behavior of the temperature dependence indicates that the formation processes of water and oxonium cations compete with each other.

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Pálinkó, István, Pál Tamás Szabó, Béla Török, Zoltán Kele, and Irén Kapocsi. "Fragmentation of cyclobutane derivatives upon electron impact: transformation pathways elucidated by mass spectrometric methods and semiempirical quantum chemical calculations." Rapid Communications in Mass Spectrometry 12, no. 22 (November 30, 1998): 1771–76. http://dx.doi.org/10.1002/(sici)1097-0231(19981130)12:22<1771::aid-rcm361>3.0.co;2-r.

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33

Mendes, Mayara Ferreira, Monica Laner Blauth, Luana Amaral Dos Santos, Vera Lúcia da Silva Valente Gaiesky, and Marco Silva Gottschalk. "Temporal edge effects structure the assemblages of Drosophilidae (Diptera) in a Restinga forest fragment in Southern Brazil." Neotropical Biology and Conservation 16, no. 2 (May 12, 2021): 299–315. http://dx.doi.org/10.3897/neotropical.16.e61481.

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Anthropogenic habitat fragmentation directly affects ecological processes, leading to negative biodiversity impacts for insects and other biota. Increased edge effects are one consequence of fragmentation, and may alter the composition or abundance of species in the remaining habitat fragments. Understanding the ways in which edge effects impact upon the biota is essential for conservation decision-making in fragmented landscapes. Therefore, the aim of this study was to analyze the seasonal patterns of abundance, richness, and composition of Drosophilidae in a Restinga forest fragment in the extreme south of Brazil, as a function of the distance from the edge to the interior of the fragment. The data were analyzed using SIMPER analyses, which showed that the edge and the forest interior were most dissimilar during winter, followed by spring, autumn and summer. An NMDS and the SIMPER analyses showed that the lower dissimilarity between the edge and interior in spring, autumn and summer, compared to winter, is driven by immigration of individuals from outside of the forest fragment. Furthermore, some species were asymmetrically distributed in the fragment, with some species restricted to the edge of the fragment and others to the interior. This information aids in the understanding of the functioning and dynamics of fragmentation, which is fundamental for the maintenance and integrity of environments and their fauna.

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34

Stevenson-Moessner, Jeanne. "Cultural Dissolution: “I Lost Africa”." Missiology: An International Review 14, no. 3 (July 1986): 313–24. http://dx.doi.org/10.1177/009182968601400305.

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Cultural consolidation, introduced in the works of Erik Erikson, is difficult for the missionary child who has often been exposed to two or three cultures, unlike the children of uni-cultural experience upon which the Eriksonian developmental theory has been built. This article introduces the concept of cultural dissolution, the fragmentation of cultural identity into its distinct cultural components. The distinctness and impact of the various cultures to which the individual has been exposed may prevent the consolidation upon which a cultural identity depends, leaving a kind of cultural confusion, a lack of consolidation. The cultural equilibrium is most often upset for multicultured missionary children in their adolescent years upon returning to their “first culture.” Not only is the phenomenon of “rootlessness” or ambiguity toward “home” explored in the article, but the implications of a theological rootlessness as well.

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35

Myagkov, N. N. "Scaling Invariance and Characteristics of the Cloud of Spherical Projectile Fragmentation Products upon High-Velocity Impact on a Thin Mesh Shield." Journal of Experimental and Theoretical Physics 126, no. 1 (January 2018): 50–63. http://dx.doi.org/10.1134/s1063776117120068.

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36

Sekiguchi, Osamu, and Susumu Tajima. "Fragmentation of organosulfur compounds upon electron impact. Part III. Metastable decomposition of the molecular ions of methyl thioglycolate and ethyl thioglycolate." Journal of the American Society for Mass Spectrometry 8, no. 8 (August 1997): 801–8. http://dx.doi.org/10.1016/s1044-0305(97)00079-2.

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37

Blaisten-Barojas, Estela. "MOLECULAR DYNAMICS STUDY OF CLUSTER GROWTH AND POLYMER DEGRADATION." International Journal of Modern Physics B 06, no. 23n24 (December 1992): 3643–55. http://dx.doi.org/10.1142/s0217979292001705.

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This work is an overview on two molecular dynamics studies of processes at temperatures characteristic of a flame — growth of silicon clusters from binary cluster collisions and thermal degradation of polymers. In the first study, silicon clusters grow as a consequence of cluster-cluster collisions by forming transient agglomerates that coalesce in a few picoseconds. The collision energy accommodates within the cluster favoring the formation of globular larger clusters regardless of the collision energy and of the impact parameter. On the average the probability for the clusters to stick upon collision is almost 1, showing clearly that the process is irreversible. The second study concerns simple polymeric chains undergoing fragmentation when they burn. These fragments are products of thermal degradation. The consorted sequence of depolymerization reactions arises after fragmentation. As a result, a sample of degrading fragments is formed where the polymer chains have dramatically coiled. These fragments self trap themselves in coiled conformations due to the cooling effect produced by the depolymerization reaction.

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Jacob, Steve. "L'institutionnalisation de l'évaluation des politiques publiques en Belgique : entre balbutiements et incantations." Res Publica 46, no. 4 (December 31, 2004): 512–34. http://dx.doi.org/10.21825/rp.v46i4.18415.

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Since a few decades, policy evaluation is a main topic in Western democracies. lt identifies, measures and appreciates effects, outcomes and impacts of a policy. Yet, there is not a common way to institutionalise that policy instrument; one can observe many differences in terms of its intensity and maturity, as well as a diversity of institutional device. Compared to other countries, Belgium is characterized by a low visibility and weak decisional impact of evaluation. Public demand for enlightening state action rarely takes the form of a demand for evaluation. The word 'Evaluation' is frequently pronounced, but most often in a political sense.In this article three types of arguments can be put forward to explain this Jack of evaluation: a lacking commitment of Parliament and political staff, the fragmentation and weak autonomy of the civil service and the domination of political parties upon the Belgian political and administrative system.

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Law, Kock-Yee, F. Court Bailey, and Lynn J. Bluett. "Squaraine chemistry. On the anomalous mass spectra of bis(4-dimethylaminophenyl)squaraine and its derivatives." Canadian Journal of Chemistry 64, no. 8 (August 1, 1986): 1607–19. http://dx.doi.org/10.1139/v86-267.

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The electron impact (EI) mass specra of bis(4-dimethylaminophenyl)squaraine 1 and its derivatives 2–14 have been studied. Ions of mass number higher than the molecular ion, which are shown to be precursors of fragment ions of lower mass numbers, are observed. From the structure–property relationship, these ions are assigned to [Formula: see text] and [Formula: see text] where CH2R is the alkyl group in the N,N-dialkylanilino moiety of squaraine. Evidence is provided that the formation of [Formula: see text] and [Formula: see text] is the result of alkyl transfer and H transfer reactions within a squaraine aggregate rather than intermolecular vapor phase reactions in the mass spectrometer. This molecular aggregate is later shown to be a trimer by analysis of metastable ion data and chemical ionization mass spectrometry. The fragmentation sequence of this trimeric species is elucidated with the assistance of metastable ions. Results show that the trimer may break down to monomelic and dimeric species upon electron impact; alternatively, the four-membered ring of the central squaraine in the trimer may cleave to generate two species of approximately equal mass number. These two species usually dominate the mass spectrum and further fragment into [Formula: see text] and [Formula: see text] Detailed fragmentation schemes for [Formula: see text] and [Formula: see text] are proposed and discussed.

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40

Santana, Marco Aurélio, and Ricardo Medeiros Pimenta. "Public History and Militant Identities: Brazilian Unions and the Quest for Memory." International Labor and Working-Class History 76, no. 1 (2009): 65–81. http://dx.doi.org/10.1017/s0147547909990093.

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AbstractThe aim of this paper is to analyze how Brazilian trade unions are using social memory as a tool to build up workers' collective identities, in an attempt to fight the fragmentation resulting from the impact of the industrial restructuring of the 1990s. We will draw upon two ongoing programs conducted by the ABC Metal Workers Union (SMABC) and the Oil Workers Union of Brazil's state oil company Petrobras (Sindipetro). The SMABC and Sindipetro have recently been addressing the issue of workers memory with social and public projects. These projects are building up memories, which in spite of being institution-based are also collective, framed by the unions through the use of new types of communication and electronic media.

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Antonsen, Tarjei, Ingrid Mann, Jakub Vaverka, Libor Nouzak, and Åshild Fredriksen. "A comparison of contact charging and impact ionization in low-velocity impacts: implications for dust detection in space." Annales Geophysicae 39, no. 3 (June 15, 2021): 533–48. http://dx.doi.org/10.5194/angeo-39-533-2021.

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Abstract. We investigate the generation of charge due to collision between projectiles with sizes below ∼1 µm and metal surfaces at speeds ∼0.1 to 10 km s−1. This corresponds to speeds above the elastic limit and well below speeds where volume ionization can occur. Impact charge production at these low to intermediate speeds has traditionally been described by invoking the theory of shock wave ionization. By looking at the thermodynamics of the low-velocity solution of shock wave ionization, we find that such a mechanism alone is not sufficient to account for the recorded charge production in a number of scenarios in the laboratory and in space. We propose a model of capacitive contact charging that involves no direct ionization, in which we allow for projectile fragmentation upon impact. Furthermore, we show that this model describes measurements of metal–metal impacts in the laboratory well. We also address contact charging in the context of ice-on-metal collisions and apply our results to rocket observations of mesospheric dust. In general, we find that contact charging dominates at speeds of up to a few kilometres per second and complements shock wave ionization up to speeds where direct ionization can take place. The conditions that we consider can be applied to dust particles naturally occurring in space and in Earth's upper atmosphere and their direct impacts on rockets, spacecraft, and impacts of secondary ejecta.

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Duplan, Yannick, Pascal Forquin, Bratislav Lukić, and Dominique Saletti. "Numerical analysis of a testing technique to investigate the dynamic crack propagation in armour ceramic." EPJ Web of Conferences 183 (2018): 02039. http://dx.doi.org/10.1051/epjconf/201818302039.

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Ceramic materials are numerically studied to understand their fracturing behaviour upon dynamic conditions and impact loadings. During a ballistic impact of a projectile against a ceramic armour system, an intense fragmentation composed of numerous oriented cracks, develops in the target. It is the reason why the conditions of crack initiation, propagation and arrest in these materials need to be investigated. In the present work, a dynamic testing configuration has been developed in order to characterise the dynamic fracture toughness (K1,d), considering a single crack that propagates from the specimen notch tip. The “Rockspall” testing technique, which employs a two-notch specimen loaded in a spalling experiment, was used. Thanks to the reflection of a compression wave into a tensile load from the sample free-end, a single dynamic crack is triggered. The sample geometry is optimised by means of a series of FE numerical simulations involving an anisotropic damage model.

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Taylor, Lee N. H., and Hugh A. Ford. "Predation of artificial nests in a fragmented landscape on the New England Tablelands of New South Wales." Wildlife Research 25, no. 6 (1998): 587. http://dx.doi.org/10.1071/wr98034.

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Artificial, cup-shaped nests containing one quail egg and one plasticine egg were placed in small (20 ha), medium-sized (90 ha) and large (350 ha) remnants of eucalypt woodland. Nests were placed near edges and centres of the two larger sites; the small site was considered all edge. Overall, 69% (659/960) of nests were preyed upon within 4 days, reflecting a high predation pressure. More nests were preyed upon in the medium-sized than in the larger or smaller sites. Loss of nests was no higher at the edge than in the centre overall, though it was significantly higher at the edge than the centre of the largest site. The main predators were identified (from beak marks on plasticine eggs) as large and medium-sized birds. Our results provide only weak support for the hypothesis that habitat fragmentation has increased predation on open nests. It is possible that nest predators and their impact have increased regionally, rather than locally. Habitat degradation may also lead to higher predation of nests, due to loss of understorey and an increase in nest predators.

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Jones, Stephanie, and Fritz Knopf. "Forty-Year Changes in the Avifauna of Grand Teton National Park, Wyoming, with Emphasis on Neotropical Migrants." UW National Parks Service Research Station Annual Reports 17 (January 1, 1993): 75–76. http://dx.doi.org/10.13001/uwnpsrc.1993.3147.

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Ornithologists and wildlife biologists have always been interested in documenting long-term changes in bird populations (e.g., Temple and Temple 1976, Kendeigh 1982). Long-term comparisons can assist in identifying patterns of change. These patterns, in turn, provide assistance in defining human impacts that may lead to some species or groups declining towards extirpation. One study specifically (Wilcove 1988) has had a major impact upon current resource issues within the Fish and Wildlife Service. That study used 40-year comparisons to confirm that fragmentation of the eastern deciduous forest had led to declines of neotropical migrants. The Wilcove (1988) study along with an essay (Hutto 1988) and an ecological study in New Hampshire (Holmes and Sherry 1988) were fundamental in identifying that declines in this group of birds cannot be blamed solely upon changes on Latin American wintering grounds. Missing from the neotropical migrant story, however, is an image of how neotropical migrants from western North America have changed in recent decades. An historical data set for comparison is available for seven vegetative associations in the vicinity of Jackson, Wyoming (Salt 1957). This project was begun in 1993 to replicate Salt's 1957 study in Grand Teton National Park. The work in 1993 was a pre-study to evaluate the potential for replicating Salt's study in the mid 1990's, 40 years after the original work.

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Fras, Teresa. "Experimental and Numerical Study on a Non-Explosive Reactive Armour with the Rubber Interlayer Applied against Kinetic-Energy Penetrators—The ‘Bulging Effect’ Analysis." Materials 14, no. 12 (June 16, 2021): 3334. http://dx.doi.org/10.3390/ma14123334.

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The study concerns a protection system applied against kinetic-energy penetrators (KEPs) composed of steel plates sandwiching a rubber layer. Laminated steel-elastomer armours represent non-explosive reactive (NERA) armours that take advantage of a so-called ‘bulging effect’ to mitigate KEP projectiles. Upon an impact, the side steel plates deform together with the deforming rubber interlayer. Their sudden deformation (bulging) in opposite directions disturbs long and slender KEP projectiles, causing their fragmentation. The presented discussion is based on the experimental investigation, confirming that the long-rod projectiles tend to fracture into several pieces due to the armour perforation. A numerical simulation accompanies the ballistic test providing an insight into the threat/target interactions. The presented experimental–numerical study explains the principles of the analysed protection mechanism and proves the efficiency of the materials composition making up the laminated non-reactive protection system.

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Saito, Leland T. "How Low–Income Residents Can Benefit from Urban Development: The LA Live Community Benefits Agreement." City & Community 11, no. 2 (June 2012): 129–50. http://dx.doi.org/10.1111/j.1540-6040.2012.01399.x.

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Large urban development projects highlight the vast disparities in the economic and political resources controlled by developers as compared to low–income residents. Studies have documented the negative impact of such projects on neighborhoods, such as the displacement of residents. This case study of the largest development project in contemporary downtown Los Angeles analyzes how a community coalition that included low–income residents successfully negotiated with the developer the first comprehensive Community Benefits Agreement (CBA) in the nation. This 2001 CBA addressed the interests of low–income residents and now serves as a model for major CBAs across the country. This article draws upon regime theory and urban political economy in examining the resources, organizations, and coalition composition behind the CBA. It suggests that CBAs represent a significant increase in political power for low–income residents when they ally with service sector unions concerned about permanent, living wage jobs. Low–income residents drew upon neighborhood and immigrant networks to organize even non–citizens. The L.A. coalition could also take advantage of the political opportunity provided by the fragmentation of growth interests and the strong real estate market in the city.

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Claude, Georges S., and R. Tabacchi. "Mass spectrometry of organometallic compounds I. the fragmentation upon electron impact of bis (η5 -cyclopentadienyl) vanadium (III) derivatives of the Cp2 v(sr) type and cp2 VCl." Bulletin des Sociétés Chimiques Belges 89, no. 10 (September 1, 2010): 875–82. http://dx.doi.org/10.1002/bscb.19800891013.

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Tserki, V., C. Panayiotou, and N. E. Zafeiropoulos. "A Study of the Effect of Acetylation and Propionylation on the Interface of Natural Fibre Biodegradable Composites." Advanced Composites Letters 14, no. 2 (March 2005): 096369350501400. http://dx.doi.org/10.1177/096369350501400202.

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Composite materials are a class of materials used in many diverse applications. Very recently the attention has shifted to the development of green composites that are easily recycleable and in this case the use of biodegradable matrices and fibres appear to be highly attractive. In the present study a class of biodegradable polyesters are used as matrices to produce fully biodegradable composites, reinforced with lignocellulosic natural fibres. This new class of composites is fully biodegradable, but the key aspect that governs the behaviour of the composites remains the interface. Surface treatments, although having a negative impact on economics, may improve the compatibility and strengthen the interface in natural fibre composite materials. In the present study the effect of two surface treatments, namely acetylation and propionylation, upon the interface of natural fibre composites is assessed by means of fragmentation tests. It has been found that both treatments led to an improvement of the stress transfer efficiency at the interface, and both applied treatments were optimised, accordingly.

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Jadidi, Mehdi, Sara Moghtadernejad, and Jack Hanson. "Numerical Study of the Effects of Twin-Fluid Atomization on the Suspension Plasma Spraying Process." Fluids 5, no. 4 (November 28, 2020): 224. http://dx.doi.org/10.3390/fluids5040224.

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Suspension plasma spraying (SPS) is an effective technique to enhance the quality of the thermal barrier, wear-resistant, corrosion-resistant, and superhydrophobic coatings. To create the suspension in the SPS technique, nano and sub-micron solid particles are added to a base liquid (typically water or ethanol). Subsequently, by using either a mechanical injection system with a plain orifice or a twin-fluid atomizer (e.g., air-blast or effervescent), the suspension is injected into the high-velocity high-temperature plasma flow. In the present work, we simulate the interactions between the air-blast suspension spray and the plasma crossflow by using a three-dimensional two-way coupled Eulerian–Lagrangian model. Here, the suspension consists of ethanol (85 wt.%) and nickel (15 wt.%). Furthermore, at the standoff distance of 40 mm, a flat substrate is placed. To model the turbulence and the droplet breakup, Reynolds Stress Model (RSM) and Kelvin-Helmholtz Rayleigh-Taylor breakup model are used, respectively. Tracking of the fine particles is continued after suspension’s fragmentation and evaporation, until their deposition on the substrate. In addition, the effects of several parameters such as suspension mass flow rate, spray angle, and injector location on the in-flight behavior of droplets/particles as well as the particle velocity and temperature upon impact are investigated. It is shown that the injector location and the spray angle have a significant influence on the droplet/particle in-flight behavior. If the injector is far from the plasma or the spray angle is too wide, the particle temperature and velocity upon impact decrease considerably.

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Prokopová, Marcela, Luca Salvati, Gianluca Egidi, Ondřej Cudlín, Renata Včeláková, Radek Plch, and Pavel Cudlín. "Envisioning Present and Future Land-Use Change under Varying Ecological Regimes and Their Influence on Landscape Stability." Sustainability 11, no. 17 (August 27, 2019): 4654. http://dx.doi.org/10.3390/su11174654.

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Climate change plays an important role in shaping ecological stability of landscape systems. Increasing weather fluctuations such as droughts threaten the ecological stability of natural and anthropogenic landscapes. Uncertainty exists regarding the validity of traditional landscape assessment schemes under climate change. This commentary debates the main factors that threaten ecological stability, discussing basic approaches to interpret landscape functioning. To address this pivotal issue, the intimate linkage between ecological stability and landscape diversity is explored, considering different approaches to landscape stability assessment. The impact of land-use changes on landscape stability is finally discussed. Assessment methodologies and indicators are reviewed and grouped into homogeneous classes based on a specific nomenclature of stability aspects which include landscape composition, fragmentation and connectivity, thermodynamic and functional issues, biodiversity, soil degradation, and ecological disturbance. By considering land-use change as one of the most important factors underlying climate change, individual components of landscape stability are finally delineated and commented upon. In this regard, specific trajectories of land-use change (including agricultural intensification, land abandonment, and urbanization) are investigated for their effects on ecological stability. A better understanding of land-use impacts on landscape stability is crucial for a better knowledge of processes leading to land degradation.

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