Effects of interactions between transient granular flows and macroscopically rough beds and their implications for bulk flow dynamics

Author(s):  
Clarence E. Choi ◽  
George Robert Goodwin

Steep-creek beds are macroscopically rough. This roughness causes channelised flow material to decelerate and dissipate energy, which are accounted for by depth-averaged mobility models (DMM). However, practical DMM implementations do not explicitly account for grain-scale basal interactions which influence macroscopic flow dynamics. In this study, we model flows using physical tests with smooth and macroscopically rough bases, and hence evaluate Discrete Element Method (DEM) and DMM models. A scaling effect is identified relating to roughened beds: increasing the number of grains per unit depth tends to suppress dispersion, such that small-scale flows on smooth beds resemble large-scale flows on roughened beds, at least in terms of bulk density. Furthermore, the DEM shows that rougher beds reduce the peak bulk density by up to 15% compared to a smooth bed. Rough beds increase the vertical momentum transfer tenfold, compared to smooth ones. The DMM cannot account for density change or vertical momentum, so DMM flow depths are underestimated by 90% at the flow front and 20% in the body. The Voellmy model implicitly captures internal energy dissipation for flows on rough beds. The parameter ξ can allow velocity reductions due to rough beds observed in the DEM to be captured.

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 52
Author(s):  
Iman Borazjani

Copepods are small aquatic creatures which are abundant in oceans as a major food source for fish, thereby playing a vital role in marine ecology. Because of their role in the food chain, copepods have been subject to intense research through different perspectives from anatomy, form-function biology, to ecology. Numerical simulations can uniquely support such investigations by quantifying: (i) the force and flow generated by different parts of the body, thereby clarify the form-function relation of each part; (ii) the relation between the small-scale flow around animal and the large-scale (e.g., oceanic) flow of its surroundings; and (iii) the flow and its energetics, thereby answering ecological questions, particularly, the three major survival tasks, i.e., feeding, predator avoidance, and mate-finding. Nevertheless, such numerical simulations need to overcome challenges involving complex anatomic shape of copepods, multiple moving appendages, resolving different scales (appendage-, animal- to large-scale). The numerical methods capable of handling such problems and some recent simulations are reviewed. At the end, future developments necessary to simulate copepods from animal- to surrounding-scale are discussed.


2021 ◽  
Author(s):  
◽  
Anne Isaac

<p>For decades, New Zealand historians and architects have sought answers to the question: What is New Zealand architecture? New Zealand longs for a place in the architectural world, seeking the significance of our buildings in the wider realm of world architecture. In 2016, in a presentation based on his book Worship: a history of New Zealand church design, Bill McKay suggested that perhaps, “our most interesting architecture lies in the intersections of our cultures”.  An opportunity is offered by the current shifts of New Zealand society where the impact of immigration on society is one of the most pressing issues that currently needs addressing. This thesis endeavours to explore the specific relationship between the heritage and culture of the existing Assyrian community and its context of Wellington, with reference to McKay’s suggestion that our most interesting architecture is birthed from the intersection of different cultures.  Socially speaking, sense of identity and place attachment play a vital role in the integration of migrant communities into their new home country. Recalling and employing elements of not only tangible Assyrian heritage, but also the intangible qualities found in traditional Assyrian architecture, has the potential to create the connection and enhance the sense of identity which allows for the feeling of belonging in migrants in their host society. This thesis focuses on the space of worship.   This project of an Assyrian Orthodox church building in New Zealand might reflect the life of the migrants who occupy it. Is it a replica of the traditional building in its original context, unchanged and uninfluenced by the shift to a new place? Or is it influenced and integrated; a building which can identify with the soil it stands on? Furthermore, if one considers that architecture reflects society, it is hoped that this design led research will participate in the discussion about New Zealand architecture’s unique identity and emerging new societal makeup.  This design led research discovers that creating a sense of belonging relies on both keeping aspects of the traditional and gaining influence from its new context. As focus shifts from the design of the building at a large scale to details and objects at a small scale, it becomes more important to reflect and retain the traditional qualities of the architecture. At a large scale, the building may be influenced by its context so as to be integrated into its new place, as if it belongs within its new urban fabric. As we move into the smaller scale in design, we draw closer to the body. It is these elements of the design which an occupant experiences more intimately, and through sensory experience and triggering memories of home, can help to create a feeling of belonging. The main findings of this research express the close relationship between architectural scales of intervention and the effects of individual and collective memory.</p>


Author(s):  
Rahul Yadav ◽  
◽  
Kamlesh Kumar Singh

Temperature control system is nothing but a complicated process which is aimed to maintain the temperature in a particular defined area to a certain maxima or minima level or say defined in a range which is quite certain. We can witness this process commonly used in many parts of the India and many other countries. In recent times, we are witnessing a rapid growth in industries at global level which has led to globalization and industrialization which further has led the necessary use of the temperature control system and its application in these industries at day-to-day level in manufacturing and maintenance with the increase in the greenhouse effect and depletion of ozone layer. Many factories both at small scale as well as at large scale always maintain a certain area or say a section of operation in their infrastructure that must maintain a range of temperature for process to work successfully. The laboratories of research uncertainly sometimes lack in the use of temperature control system which has further necessitated the use of large chambers of different sizes to perform specific temperature related re-search work which further led to the increase in the cost of research work. In certain specific areas there are lot of electronic activities happening or some machinery function like in the server rooms or the area where production plant is, so basically these places work constantly for 24hrs and during the whole day the temperature has to be monitored precisely and frequently so that it can be ensured that the temperature do not instantly rise or fall below the marked temperature which may lead to the acceleration of wearing and tearing of whole system. Living rooms, hospitals, malls, aircrafts etc., are also one of the most important places where monitoring of temperature is required so as to ensure that the thermal comfort is ensured, and thermal comfort here means that the state of mind which feels satisfied with the temperature in the present environment. This is important because if there will be any dissatisfaction with the thermal environment then it can cause the body to be too warm or too by unwanted heating and unwanted cooling of the equipment may further lead to the functional disbalance.


2018 ◽  
Vol 12 (1) ◽  
pp. 151-170
Author(s):  
Hannah Vandegrift Eldridge

Abstract In recent years, theories of rhythm have been proposed by a number of different disciplines, including historical poetics, generative metrics, cognitive literary studies, and evolutionary aesthetics. The wide range of fields indicates the transdisciplinary nature of rhythm as a phenomenon, as well as its complexity, highlighting the degree to which many of the central questions surrounding rhythm remain extraordinarily difficult even to state in terms that can traverse the disciplinary boundaries effortlessly transgressed by rhythm as a phenomenon. In particular, any theory of rhythm, whether in music, dance, sociology, or language, must grapple with two quandaries. First, the precise site of rhythm remains opaque: rhythms occur in, affect, and are produced by all of bodies, cultures, and universals (whether metaphysical or species-physiological). What is the relation between species-wide characteristic, individual body, cultural context, and the history of art making in the experience of rhythm? Second, rhythm is simultaneously a phenomenon of fixed, organizing form and one of dynamic, changing flow. How can rhythm encompass both the measurement of regular recurrences across time and the organizing of temporal phenomena as they unfold? In this article, I draw on Emile Benveniste and Henri Meschonnic to elucidate these quandaries or conflicts before turning to Friedrich Nietzsche’s work on rhythm. I argue that Nietzsche’s work with rhythm provides a historically situated model for how we might continue to take the questions and conflicts within rhythm seriously, rather than privileging an abstract and universally applicable theory of rhythm. This model is especially crucial for our own historical moment, when cultural-political emphasis on science and technology at the expense of aesthetics devalues all insights not presented in the form of countable data points or empirically testable facts. Nietzsche is, of course, one of the great critics of positivist-scientistic epistemologies, part of a long tradition questioning the naturalness of natural-scientific paradigms and alerting us to the metaphors at play even in the ›hard sciences‹. I use rhythm as one paradigmatic place to resist the importation of scientistic thought into discussions of language, literature, and culture. I show how Nietzsche’s writings on rhythm prove illuminating for contemporary understandings of rhythm because the tensions in his work are shaped by the quandaries inherent to rhythm that I have used Benveniste and Meschonnic to elaborate, namely the question of rhythm’s site as individual, cultural, or universal, and the conflict between rhythm as form and as flow. The question of the site of rhythm appears in Nietzsche’s discussions of Greek and Latin meters both in his philological works, in his aphorisms, and in his letters: on the one hand, he argues that Greek and Latin metrical and rhythmic resources are irrevocably lost to modern cultures (indicating that rhythm is a product of culture), while on the other, he emphasizes the impact of rhythm on the body and offers advice for replicating Ancient metrical and rhythmic techniques (suggesting that rhythm is based on physiological universals). And the conflict between flow and form appears as Nietzsche praises both the productive constraint created by large-scale, architectonic, or macro-formal rhythms and the freedom from such constraint enabled by small-scale, leitmotiv-based, or micro-formal rhythms. The conflicts in Nietzsche’s work between the loss and recovery of Ancient rhythms and between rhythm as small scale freedom vs. large scale constraint thus represent one particular unfolding of the dilemmas for rhythmical theory worked out by Benveniste and Meschonnic. The various modern disciplines engaged with rhythm will answer different sets of these questions in different ways. Most practitioners of, e. g., evolutionary aesthetics, neuroaesthetics, or cognitive poetics would no doubt contend that they are using the tools of the natural sciences to investigate long-standing humanistic inquiries. Nietzsche, as a critic of his own era’s scientific positivism who allows tensions inherent in these questions to remain open in his own work, is an ideal interlocutor with whom to ask whether even the adoption of these tools ends up placing excessive faith in natural-scientific paradigms and undercutting other—affective, bodily, metaphorical, poetic, etc.—ways of knowing, as I demonstrate briefly in the examples of evolutionary aesthetics and generative metrics. Because Nietzsche leaves open the conflicts over rhythm’s site and its qualities as form or flow, he can use individual bodily experience to make physiological arguments about the effects of rhythm on culture and vice versa: Nietzsche takes his bodily response to be an index of cultural values inherent to rhythmical practices. The particular values that Nietzsche critiques shift across his career—early on he condemns German musical and poetic rhythms for being too rigid, while later he sees them as pathologically heightening affect and emotion. In both cases, detrimental rhythmic practices lead to detrimental bodily practices and to the degeneration of culture, while rhythmic practices work as a bodily and cultural corrective. In his critiques of German forms and praises of Greek forms, and in the moments in which he brings them together, Nietzsche thus asserts the complex interrelation of culture, body, and history.


2020 ◽  
Vol 644 ◽  
pp. A50
Author(s):  
Lizxandra Flores-Rivera ◽  
Mario Flock ◽  
Riouhei Nakatani

Context. In recent years hydrodynamical (HD) models have become important to describe the gas kinematics in protoplanetary disks, especially in combination with models of photoevaporation and/or magnetically driven winds. Our aim is to investigate how vertical shear instability (VSI) could influence the thermally driven winds on the surface of protoplanetary disks. Aims. In this first part of the project, we focus on diagnosing the conditions of the VSI at the highest numerical resolution ever recorded, and suggest at what resolution per scale height we obtain convergence. At the same time, we want to investigate the vertical extent of VSI activity. Finally, we determine the regions where extreme UV (EUV), far-UV (FUV), and X-ray photons are dominant in the disk. Methods. We perform global HD simulations using the PLUTO code. We adopt a global isothermal accretion disk setup, 2.5D (2 dimensions, 3 components) which covers a radial domain from 0.5 to 5.0 and an approximately full meridional extension. Our simulation runs cover a resolution from 12 to 203 cells per scale height. Results. We determine 50 cells per scale height to be the lower limit to resolve the VSI. For higher resolutions, ≥50 cells per scale height, we observe the convergence for the saturation level of the kinetic energy. We are also able to identify the growth of the “body” modes, with higher growth rate for higher resolution. Full energy saturation and a turbulent steady state is reached after 70 local orbits. We determine the location of the EUV heated region defined by Σr = 1019 cm−2 to be at HR ~ 9.7 and the FUV–X-ray heated boundary layer defined by Σr = 1022 cm−2 to be at HR ~ 6.2, making it necessary to introduce a hot atmosphere. For the first time we report the presence of small-scale vortices in the r − Z plane between the characteristic layers of large-scale vertical velocity motions. Such vortices could lead to dust concentration, promoting grain growth. Our results highlight the importance of combining photoevaporation processes in the future high-resolution studies of turbulence and accretion processes in disks.


2021 ◽  
Author(s):  
◽  
Anne Isaac

<p>For decades, New Zealand historians and architects have sought answers to the question: What is New Zealand architecture? New Zealand longs for a place in the architectural world, seeking the significance of our buildings in the wider realm of world architecture. In 2016, in a presentation based on his book Worship: a history of New Zealand church design, Bill McKay suggested that perhaps, “our most interesting architecture lies in the intersections of our cultures”.  An opportunity is offered by the current shifts of New Zealand society where the impact of immigration on society is one of the most pressing issues that currently needs addressing. This thesis endeavours to explore the specific relationship between the heritage and culture of the existing Assyrian community and its context of Wellington, with reference to McKay’s suggestion that our most interesting architecture is birthed from the intersection of different cultures.  Socially speaking, sense of identity and place attachment play a vital role in the integration of migrant communities into their new home country. Recalling and employing elements of not only tangible Assyrian heritage, but also the intangible qualities found in traditional Assyrian architecture, has the potential to create the connection and enhance the sense of identity which allows for the feeling of belonging in migrants in their host society. This thesis focuses on the space of worship.   This project of an Assyrian Orthodox church building in New Zealand might reflect the life of the migrants who occupy it. Is it a replica of the traditional building in its original context, unchanged and uninfluenced by the shift to a new place? Or is it influenced and integrated; a building which can identify with the soil it stands on? Furthermore, if one considers that architecture reflects society, it is hoped that this design led research will participate in the discussion about New Zealand architecture’s unique identity and emerging new societal makeup.  This design led research discovers that creating a sense of belonging relies on both keeping aspects of the traditional and gaining influence from its new context. As focus shifts from the design of the building at a large scale to details and objects at a small scale, it becomes more important to reflect and retain the traditional qualities of the architecture. At a large scale, the building may be influenced by its context so as to be integrated into its new place, as if it belongs within its new urban fabric. As we move into the smaller scale in design, we draw closer to the body. It is these elements of the design which an occupant experiences more intimately, and through sensory experience and triggering memories of home, can help to create a feeling of belonging. The main findings of this research express the close relationship between architectural scales of intervention and the effects of individual and collective memory.</p>


2020 ◽  
Vol 223 (1) ◽  
pp. 270-288
Author(s):  
Nooshin Saloor ◽  
Emile A Okal

SUMMARY We explore the possible theoretical origin of the distance–depth correction q(Δ, h) introduced 75 yr ago by B. Gutenberg for the computation of the body-wave magnitude mb, and still in use today. We synthesize a large data set of seismograms using a modern model of P-wave velocity and attenuation, and process them through the exact algorithm mandated under present-day seismological practice, to build our own version, qSO, of the correction, and compare it to the original ones, q45 and q56, proposed by B. Gutenberg and C.F. Richter. While we can reproduce some of the large scale variations in their corrections, we cannot understand their small scale details. We discuss a number of possible sources of bias in the data sets used at the time, and suggest the need for a complete revision of existing mb catalogues.


2000 ◽  
Vol 45 (4) ◽  
pp. 396-398
Author(s):  
Roger Smith
Keyword(s):  

2020 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
Evi Rahmawati ◽  
Irnin Agustina Dwi Astuti ◽  
N Nurhayati

IPA Integrated is a place for students to study themselves and the surrounding environment applied in daily life. Integrated IPA Learning provides a direct experience to students through the use and development of scientific skills and attitudes. The importance of integrated IPA requires to pack learning well, integrated IPA integration with the preparation of modules combined with learning strategy can maximize the learning process in school. In SMP 209 Jakarta, the value of the integrated IPA is obtained from 34 students there are 10 students completed and 24 students are not complete because they get the value below the KKM of 68. This research is a development study with the development model of ADDIE (Analysis, Design, Development, Implementation, and Evaluation). The use of KPS-based integrated IPA modules (Science Process sSkills) on the theme of rainbow phenomenon obtained by media expert validation results with an average score of 84.38%, average material expert 82.18%, average linguist 75.37%. So the average of all aspects obtained by 80.55% is worth using and tested to students. The results of the teacher response obtained 88.69% value with excellent criteria. Student responses on a small scale acquired an average score of 85.19% with highly agreed criteria and on the large-scale student response gained a yield of 86.44% with very agreed criteria. So the module can be concluded receiving a good response by the teacher and students.


2019 ◽  
Vol 61 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Loretta Lees

Abstract Gentrification is no-longer, if it ever was, a small scale process of urban transformation. Gentrification globally is more often practised as large scale urban redevelopment. It is state-led or state-induced. The results are clear – the displacement and disenfranchisement of low income groups in favour of wealthier in-movers. So, why has gentrification come to dominate policy making worldwide and what can be done about it?


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