Collision of a Field-Driven Polymer with a Post: Implications for Electrophoresis in Microlithographic Arrays

1996 ◽  
Vol 463 ◽  
Author(s):  
E. M. Sevick ◽  
D.R.M. Williams

ABSTRACTWe study the simplest model of a polyelectrolyte impinging upon a point, frictionless obstacle in the presence of a field. Using numerical simulation, we show that the wide range of impacts, ranging from direct impact forming a long-lived hairpin conformation, to glancing impacts where the chain slides off of the obstacle in short time, can be described universally. In strong field, the average collision time, 〈tc〉, and average distance traveled during collision, 〈zc〉, depend upon the impact and follow universal curves over a large range of molecular weights and field strengths. This result provides analytic formulas for the chain's mobility in an array of posts and yields insight into the effect of post spacing.

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 519
Author(s):  
Vitalii Bezgin ◽  
Agata Dudek ◽  
Adam Gnatowski

This paper proposes and presents the chemical modification of linear hydroxyethers (LHE) with different molecular weights (380, 640, and 1830 g/mol) with the addition of three types of rubbers (polysulfide rubber (PSR), polychloroprene rubber (PCR), and styrene-butadiene rubber (SBR)). The main purpose of choosing this type of modification and the materials used was the possibility to use it in industrial settings. The modification process was conducted for a very wide range of modifier additions (rubber) per 100 g LHE. The materials obtained in the study were subjected to strength tests in order to determine the effect of the modification on functional properties. Mechanical properties of the modified materials were improved after the application of the modifier (rubber) to polyhydroxyether (up to certain modifier content). The most favorable changes in the tested materials were registered in the modification of LHE-1830 with PSR. In the case of LHE-380 and LHE-640 modified in cyclohexanol (CH) and chloroform (CF) solutions, an increase in the values of the tested properties was also obtained, but to a lesser extent than for LHE-1830. The largest changes were registered for LHE-1830 with PSR in CH solution: from 12.1 to 15.3 MPa for compressive strength tests, from 0.8 to 1.5 MPa for tensile testing, from 0.8 to 14.7 MPa for shear strength, and from 1% to 6.5% for the maximum elongation. The analysis of the available literature showed that the modification proposed by the authors has not yet been presented in any previous scientific paper.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Doron Azoury ◽  
Michael Krüger ◽  
Barry D. Bruner ◽  
Olga Smirnova ◽  
Nirit Dudovich

AbstractThe Coulomb interaction between a photoelectron and its parent ion plays an important role in a large range of light-matter interactions. In this paper we obtain a direct insight into the Coulomb interaction and resolve, for the first time, the phase accumulated by the laser-driven electron as it interacts with the Coulomb potential. Applying extreme-ultraviolet interferometry enables us to resolve this phase with attosecond precision over a large energy range. Our findings identify a strong laser-Coulomb coupling, going beyond the standard recollision picture within the strong-field framework. Transformation of the results to the time domain reveals Coulomb-induced delays of the electrons along their trajectories, which vary by tens of attoseconds with the laser field intensity.


2018 ◽  
Vol 7 (2.28) ◽  
pp. 234 ◽  
Author(s):  
Karolina Kuligowska ◽  
Paweł Kisielewicz ◽  
Aleksandra Włodarz

The present speech synthesis systems can be successfully used for a wide range of diverse purposes. However, there are serious and important limitations in using various synthesizers. Many of these problems can be identified and resolved. The aim of this paper is to present the current state of development of speech synthesis systems and to examine their drawbacks and limitations. The paper dis-cusses the current classification, construction and functioning of speech synthesis systems, which gives an insight into synthesizers implemented so far. The analysis of disadvantages and limitations of speech synthesis systems focuses on identification of weak points of these systems, namely: the impact of emotions and prosody, spontaneous speech in terms of naturalness and intelligibility, preprocessing and text analysis, problem of ambiguity, natural sounding, adaptation to the situation, variety of systems, sparsely spoken languages, speech synthesis for older people, and some other minor limitations. Solving these problems stimulates further development of speech synthesis domain. 


Author(s):  
JASON SETH GOLDSTEIN ◽  
EHUD SPANIER

Temperature serves a predominant motivator for movement and activity over a wide range of mobile marine ectotherms. Water temperature modulates the movements of many lobster species, which can vary widely over spatial and temporal scales. Providing insight into the thermal preferences (and refuges) that some lobsters seek remains a key tenet to our understanding of the behavioral ecology of these animals. The Mediterranean slipper lobster (Scyllarides latus) shows seasonal movements throughout most of its range and is subject to a changing thermal environment. We examined the seasonal movements of S. latus within a small marine reserve (Rosh Hanikra Marine Reserve, RHR) off the coast of Israel and tested the hypothesis that S. latus engage in increased movements when subjected to temperatures outside their range. We conducted a field survey in the RHR and tagged lobsters (n = 81, carapace length, CLavg= 88.7 ± 4.6) to investigate their activity during their putative summer movement. In the lab, we exposed a separate set of lobsters (n = 10, CLavg= 83.1 ± 6.1) to the same thermal profiles as in the field and assayed their locomotion using activity wheels. Field results revealed that lobsters tagged in shallow waters moved to deeper, cooler waters (~ 30 m) over the course of 2-2.5 months traveling an average distance of 3.4 km (range = 1-5 km). Our lab results showed that S. latus are more active at higher temperatures, but moreover, revealed that warming water temperatures elicited markedly longer movements over a similar timeframe. Combined, these findings suggest that increasing water temperatures in the eastern Mediterranean (Levant) may affect lobster movements and could alter seasonal patterns of distribution as well.


2007 ◽  
Vol 46 (9) ◽  
pp. 1480-1497 ◽  
Author(s):  
Olivier P. Prat ◽  
Ana P. Barros

Abstract The focus of this paper is on the numerical solution of the stochastic collection equation–stochastic breakup equation (SCE–SBE) describing the evolution of raindrop spectra in warm rain. The drop size distribution (DSD) is discretized using the fixed-pivot scheme proposed by Kumar and Ramkrishna, and new discrete equations for solving collision breakup are presented. The model is evaluated using established coalescence and breakup parameterizations (kernels) available in the literature, and in that regard this paper provides a substantial review of the relevant science. The challenges posed by the need to achieve stable and accurate numerical solutions of the SCE–SBE are examined in detail. In particular, this paper focuses on the impact of varying the shape of the initial DSD on the equilibrium solution of the SCE–SBE for a wide range of rain rates and breakup kernels. The results show that, although there is no dependence of the equilibrium DSD on initial conditions for the same rain rate and breakup kernel, there is large variation in the time that it takes to reach steady state. This result suggests that, in coupled simulations of in-cloud motions and microphysics and for short time scales (<30 min) for which transient conditions prevail, the equilibrium DSD may not be attainable except for very heavy rainfall. Furthermore, simulations for the same initial conditions show a strong dependence of the dynamic evolution of the DSD on the breakup parameterization. The implication of this result is that, before the debate on the uniqueness of the shape of the equilibrium DSD can be settled, there is critical need for fundamental research including laboratory experiments to improve understanding of collisional mechanisms in DSD evolution.


2021 ◽  
Author(s):  
Natalie Ramtahal

This MRP will examine how food can be used as a tool for challenging traditional nation stories and growing notions of what it means to be Canadian. There is an opportunity to write and shape a Canadian narrative that is inclusive of its evolving demography while simultaneously reconciling its violent history by developing a Canadian culinary identity. Food is political, social and cultural. Food can bring people together and can provide a platform to have compelling discussions about what it means to be Canadian; who is included in the definition of Canadian; and, how we can develop a sense of Canadianness that speaks to an evolving population. Historically and at present, Canada’s story has often excluded or minimized the cultural, political and social contributions of Indigenous peoples and racialized immigrants. There remains a prevailing sense of Canadian identity being tethered to whiteness despite over a century of global immigration. However, the very idea of what defines Canadianness is relatively tenuous one. There are few traits, markers, or qualities that are seen as characteristically Canadian. This is even more true for Canada’s culinary identity. What exactly is Canadian food? Canada, as a nation, is a relatively new country without a clear culinary identity. Further, Canada is an expansive land mass covering different time zones, geographic regions, and climates. To further complicate matters, it is place for people from all over the world to immigrate. Nowhere is the impact of immigration and the diversity of people more evident than in Toronto. How the city has changed demographically is reflected in the diversification of it’s culinary landscape. The wide range of available foods reveals and affirms how the appetites and desires of those that live here have also changed. International foods, restaurants and markets are not only ubiquitous, but a defining characteristic of the city. Where, what and how people eat can provide insight into how historical systems of inequality and colonial narratives persist. Growing and developing Canadian culinary identity is a way of challenging the idea of whiteness as a prerequisite for being Canadian. It is a potential way to acknowledge and include immigrant contributions. Food is wrapped up in politics of inequality and injustice, just as much as it is in pleasure and desire. Mapping how food is used as a tool that furthers colonization and racist dogma is key for shifting food to a tool for education and understanding. Food has the power to open up conversation and reshape understandings of Canadian identity through developing and defining a distinct Canadian culinary position. If an understanding about Canadian culinary identity is inclusive of its complex and divergent cultural and political history, then perhaps there is an opportunity to rethink Canadian identity as a whole. The goal of this MRP is to establish that food can be used as an ideological intervention that examines, challenges and reimagines Canadian identity.


2019 ◽  
Vol 5 (4) ◽  
pp. 280-287
Author(s):  
D. Shvaiba

Taking as a basis the scientific study of different concepts in the theory of security, it is necessary to assume that the inaccessibility of the threat in the absolute sense is impossible. In fact, there may not be a certain type of threat to a particular object in a specific period of time (if there is not yet or there is no longer a corresponding danger factor). It is necessary to take into account that interests are only a small part of a wide range of objects of state protection. This share differs subjectively and interacts with the implemented financial, economic and social policy, the productivity of which is largely dependent on the impact of individual groups of people and parties (based on socio–political preferences). In addition — it is quite a mobile category, which has the ability to change qualitatively. It is obvious that the danger is one of the many destructive moments of security, along with those of which have already been discussed, for example threat, challenge, risk, decline, crisis, cataclysm, destruction, deformation processes, etc. It is necessary to clarify that the danger in the context of the ‘security triad’ is always modified: in a short time, they have all chances to transform from the present into the probable and vice versa.


2020 ◽  
Author(s):  
Laura Mulvey ◽  
Bryan Shirley ◽  
Fiona Pye ◽  
Nussaïbah B. Raja ◽  
Emilia Jarochowska

<p>One of the most versatile tools in a palaeontologists’ “tool-kit” is body size analysis, which can be used to characterise and quantify a wide range of ecological and physiological traits.  Utilisation of these data allows insight into predator prey relationships, respiration rates, mortality rates, and even population dynamics. Body size analysis becomes essential when studying extinct organisms where few other clues to their ecology are available. An extreme example of such organisms are conodonts, which are hypothesised to be among the first predators.  Here, changes are tracked  through the Silurian Period using coniform conodont elements as a proxy for body size. Previous research focuses primarily on species turnover, however the data collected in this study is independent of species identification, relying purely on body size changes to reflect the ecology of the community. The size of coniform elements are measured across a number of bathymetries spanning approximately 10 million years. This allows a comparison of body size change not only across differing environments, but also through time. The morphometric measurements were determined using FossilJ, a plugin for ImageJ which facilitates semi-automated measurement of two-dimensional images. Firstly, our results show a clear correlation between body size change and onshore offshore gradients with smaller organisms residing at shallower water depths, unlike what is seen in today’s oceans. Secondly, specimens span across two of the three recorded isotopic excursions during the Silurian Period, the Mulde and Lau events. The impact of these events on conodont communities is represented by a reduction in body size directly after each. Furthermore, the results suggest the Mulde event may have had a stronger effect on these communities and could potentially reflect a time of stress and/or extinction for coniform conodonts.</p>


2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Jinzhao Tian

In the face of ever-increasing globalisation, the question of how to manage project teams efficiently andsuccessfully was never likely to be settled easily. It has been shown that 92% of project team members believe that softskiils are needed in their teamwork, 60% think that soft skill impacts project management, and 83% hold the view thatsoft skill is relevant to the performance of project teams. The research aims to help overseas project managers to obtaingreater insight into the impact of soft skill on project teams and so manage them more effectively. The introduction contextpresents the general concepts of soft skills and project management. Through a wide range of cases and examples ofproject teams, the impact of those skills on project teams will be explored.


Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3123 ◽  
Author(s):  
Rafael Paseiro-Cerrato ◽  
Lowri DeJager ◽  
Timothy H. Begley

In this study, an accelerated migration test on food can coatings into food simulants was investigated. Food simulants covering a wide range of polarity were used to conduct migration tests at 60 °C with storage times ranging from 4 h to 30 days. Epoxy-resins, acrylic–phenolic, polyester, and vinyl coatings were exposed to water, 3% acetic acid, 50% ethanol, and Miglyol 812®. Using liquid chromatography coupled to a variety of detectors (UHPLC-Q-Orbitrap-MS, UFLC-MS/MS, and HPLC-DAD), migration of several monomers and previously identified oligomers, as well as some unidentified migrants, were determined during the experiment. The data from this study was compared to our findings from previous long-term migration studies with storage times ranging from 24 h to 540 days at 40 °C using the same can coating applications. The results illustrate that performing migration experiments for short time periods at 60 °C may mimic migration results that would be obtained at 40 °C after long-term migration tests (up to 1.5 years) from food can coatings into food simulants.


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