Gotowa bibliografia na temat „Shallow Point Packing”

AbstractWind-tunnel experiments were carried out on four urban morphologies: two tall canopies with uniform height and two super-tall canopies with a large variation in element heights (where the maximum element height is more than double the average canopy height, $$h_{max}=2.5h_{avg}$$ h max = 2.5 h avg ). The average canopy height and packing density are fixed across the surfaces to $$h_{avg} = 80~\hbox {mm}$$ h avg = 80 mm , and $$\lambda _{p} = 0.44$$ λ p = 0.44 , respectively. A combination of laser Doppler anemometry and direct-drag measurements are used to calculate and scale the mean velocity profiles with the boundary-layer depth $$\delta $$ δ . In the uniform-height experiment, the high packing density results in a ‘skimming flow’ regime with very little flow penetration into the canopy. This leads to a surprisingly shallow roughness sublayer (depth $$\approx 1.15h_{avg}$$ ≈ 1.15 h avg ), and a well-defined inertial sublayer above it. In the heterogeneous-height canopies, despite the same packing density and average height, the flow features are significantly different. The height heterogeneity enhances mixing, thus encouraging deep flow penetration into the canopy. A deeper roughness sublayer is found to exist extending up to just above the tallest element height (corresponding to $$z/h_{avg} = 2.85$$ z / h avg = 2.85 ), which is found to be the dominant length scale controlling the flow behaviour. Results point toward the existence of a constant-stress layer for all surfaces considered herein despite the severity of the surface roughness ($$\delta /h_{avg} = 3 - 6.25$$ δ / h avg = 3 - 6.25 ). This contrasts with the previous literature.

Lack of soil physical data, particularly soil water release data and hydraulic conductivity data, is recognised as one of the greatest limitations to the widespread application of simulation models, needed to address environmental issues. Because of the expense of generating new soil physical data pedotransfer functions may be used to predict soil physical data from existing information, notably soil morphology. Pedological horizon descriptions can then be used to estimate soil physical properties for many points in the landscape. The soils used in this study were derived from a systematic sampling of soil profiles for soil physical characteristics for 8 soils series within 2 drainage sequences on the post-glacial and glacial surfaces of the Canterbury Plains. Soil series in each sequence varied from shallow sandy loam, well-drained soils to deep clay loam, poorly drained soils. Each soil series was represented by 9 profiles. Three horizons in each soil profile were sampled for soil porosity values, particle size, and saturated- and near-saturated hydraulic conductivity. Pedological horizons were grouped into functional horizons on the basis of soil morphologic attributes expected to have closest relationships with soil physical properties (ped size, ped type, packing class, consistence and presence of argillic horizons). For topsoils, functional horizons based on ped size were found to have greatest predictive ability and provided separation between horizons for bulk density, macroporosity, clay content, wilting point, readily available water, and near-saturated hydraulic conductivity. For subsoils, horizons with clay content >35% had distinct relationships with soil physical properties and needed to be separated from other subsoil horizons. For the remaining horizons, separations in soil water release characteristics and some hydraulic conductivity data were obtained by functional horizons based on packing class and the presence of argillic horizons. Adding ped size to the functional horizon definition provided further separation of horizons for hydraulic conductivity. This study demonstrates that a range of pedological horizons, derived from a wide range of soil types, can be grouped into 4 functional topsoil horizons and 3–5 functional subsoil horizons on the basis of simple morphological attributes or merged pedological horizons. The functional horizons, thus created, enable statistical distributions of soil water release and hydraulic conductivity data to be predicted for map units.

From the start of this century there has been a proliferation not only in the study of neurosciences and the physiology of perception/emotion, but also in its dissemination. This has resulted in countless programs, courses, etc., that pretend to help the designer, be it architectural, advertising, product, packaging or others (Ulrich, R. S. 1999) to appropriately impact the experience of the end user; tendencies such as biophilia, neuromarketing, user centered design, the influence of color in a space (Aseel AL-Ayash, Robert T. Kane, Dianne Smith, Paul Green-Armytage, 2016), or the impact on behavior and the brain when observing works of art (Kendall J. Eskine, Natalie A. Kacinik, Jesse J. Prinz, 2012), are intended to give us answers based on the neurology and physiology of perception/emotion. Nevertheless, it is hard to separate science from pseudoscience, and even to organize into a useful model the copious scientific information available. The objective is to present a theoretical model that incorporates and synthesizes the state of knowledge in this field, to facilitate its application in the diverse art and design disciplines; this will help both the creator-artist to have a better understanding of their process and comprehension of their work, as well as the designer, to be able to predict the impact their projects will have upon the audience they are directed towards. We are talking from photographers and painters, to architects and illustrators, etc. The methodology consists mainly in the exegesis — and organization of the material resulting thereof — of basic text on this field. In this talk, we present the Theory of Emotive Reactions model, that has been developing in Tijuana since the beginning of this century, we give a shallow explanation of its scientific foundations, we point out its correlation with the state of knowledge and we present the basic principles for its application in the diverse artistic and design disciplines. Key words: design, emotion, neurosciences, perception, end user experience

The electrical transport properties of anatase TiO₂ polycrystalline have been systematically investigated using high pressure in-situ impedance spectroscopy measurements. The anomalous behaviors of resistance, parameter factor and relaxation frequency of grain and grain boundary can be found at 6.4, 11.5 and 24.6 GPa. Results indicate that the former two discontinuous points (6.4 and 11.5 GPa) correspond to the phase transitions of TiO₂ from anatase to a-PbO₂ and then to baddeleyite, respectively. Above 24.6 GPa, TiO₂ completely transforms into the baddeleyite phase. Based on the change of grain and grain boundary resistance under pressure, intrinsic defects play a crucial effect on the electrical transport properties of TiO₂ at high pressure. At 6.4 GPa, the occurrence of phase transition gives rise to the variation of defects' role, from a deep energy level defect (as a recombination centre) changes into a shallow energy level defect (providing carriers to the conduction and valence bands). In addition, the position of defect in energy band changes with pressure increasing. Furthermore, the phase transition of TiO₂ at 6.4 GPa is the rearrangement of TiO₆ octahedron, while the other one at 11.5 GPa can be attributed to the migration of oxygen Schottky defects from inner to surface. Combining the packing factor and relaxation frequency, the electrical transport properties of TiO₂ under pressure are revealed, the packing factor and the relaxation frequency are closely related to the mobility and the carrier concentration, respectively. The activation energies of grain and grain boundary decrease as the pressure elevating, indicating that the transport of carriers in grain and grain boundary become easier under pressure, and the former is smoother than the latter due to the activation energy of grain is smaller than that of grain boundary in the same pressure range. Moreover, the relaxation frequency ratio of grain and grain boundary of TiO₂ decreases with pressure increasing, and the grain boundary effect under high pressure is not obvious.

We study a host of geometric optimization problems that are NP-hard and design polynomial time approximation algorithms for them. More precisely, we are given a family of geometric objects and a point set, mostly in the plane, and study different variants and generalizations of Packing and Covering problems. Our objects of study are mostly family of non-piercing regions in the plane. We call a set of simple and connected regions to be non-piercing if for any pair of intersecting regions, A and B both A\B and B\A are connected regions. A set of disks, squares, half-planes are examples of non-piercing regions, whereas, a set of lines, rectangles are examples of piercing objects. For most of the problems we have studied, a simple local search algorithm is enough to yield a PTAS whose analysis of approximation requires a suitable bipartite graph on the local search solution and the optimal solution to have a balanced sub-linear separator. We study a generalization of the standard packing problem, called the Capacitated Region Packing problem and its slight variant, the Shallow Packing problem. We devise a PTAS for both these problems with restrictions on the capacities. For the former problem, the objects are non-piercing whereas for the latter problem the objects can be even more general and only have sub-quadratic union complexity with the capacities at most some constant for both the cases. The non-triviality here is to show that the intersection graph of arrangements with shallow depth, which is not planar, has balanced sub-linear separators. Our results complement the Maximum Independent Set of Rectangles problem as rectangles are both piercing and have quadratic union complexity. We also study the Shallow Point Packing problem and are able to show that local search works here as well for unit capacity and devise a constant factor approximation algorithm using an adaptation Brannaman-Goodrich technique for packing problems. Runaway Rectangle Escape problem is closely related to the above packing problems and is motivated from routing in printed circuit boards. Here we are given a set of axis-parallel rectangles inside a rectangular boundary R and a maximum allowed depth d. The objective is to extend the maximum number of input rectangles to one of the four sides of R such that the maximum depth of a point is at most d after extension. We show that local search gives a (2 + )-approximation for d = O(1). When the input rectangles are all disjoint then we devise a simple 4(1 + 1=(d 􀀀 1))-approximation algorithm. We also propose a randomized (1 + )-approximation algorithm based on randomized rounding making some density assumptions. Lastly, we show the problem to be NP-hard even when the rectangles are unit squares aligned in a grid. We study the Multi-Cover problem which is a generalization of the Set Cover problem. We give a PTAS for non-piercing regions when the depth of every point is at most constant. We also study different variants of the covering problem like the Unique Coverage, and Prize Collecting Set Cover problem. For Unique Cover we show that local search yields a PTAS for non-piercing regions for bounded depth and degree. For Prize Collecting Set Cover a PTAS works for non-piercing regions if the weight of every region is within a range [1; a], where a is some constant. Lastly, we consider variants of the Art Gallery problems called the Minimum (Horizontal) Sliding Cameras problem, M(H)SC. We are given an orthogonal polygon and we need to deploy mobile guards who can walk along an orthogonal (horizontal) line segment and can guard a point inside the polygon if the perpendicular drawn from the point onto the line segment lies inside the polygon. Our local search algorithm yields a PTAS for the MHSC problem and also the MSC problem when the polygon has no holes. In order to do so we prove an appropriate graph on orthogonal line segments to be planar by proposing a graph drawing scheme.

Abstract The centrifugal particle receiver (CentRec), a direct absorbing receiver operating with ceramic particles, demonstrated at the Julich solar power tower under solar conditions technical large-scale feasibility, generating particle outlet temperatures up to 965 °C. To push particle based CSP technology further towards commercial application the high particle temperatures have to be transferred to a working fluid, like air. A gas-particle trickle flow direct contact heat exchanger (TFHX) has been identified with great potential for high efficiency heat transfer. Inspired by chemical trickle flow reactors and previous work in literature focusing on the gas-particle TFHX concept for temperatures up to 500 °C, the approach and its applicability for high temperature heat exchanger shall be developed further in future. In preparation for subsequent research activities, the present work focuses on the preliminary selection of suitable packing structures for the TFHX. Packing assessment criteria are defined and used to assess the particle behavior within a variety of 44 different packing geometries. The analysis was performed using the open source DEM software LIGGHTS-PUBLIC whereas at this early stage of investigation gas presence was neglected. In the analysis process the packing structures are assessed with the previously defined assessment criteria and reduced to one type of a favorable geometry type. In conclusion, the advantageous characteristics of the identified geometry type are discussed. The presented study gives a methodical selection for packing structures and first starting point for further investigating in the field of the gas-particle TFHX whereas in subsequent work the influence of gas flow to the particle dynamic must be investigated by experimental and simulation work.