vertical extension
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Fluids ◽  
2021 ◽  
Vol 6 (12) ◽  
pp. 447
Author(s):  
Marcello Lappa ◽  
Aydin Sayar ◽  
Wasim Waris

Convection induced in a layer of liquid with a top free surface by a distribution of heating elements at the bottom can be seen as a variant of standard Marangoni–Rayleigh–Bénard Convection where in place of a flat boundary at constant temperature delimiting the system from below, the underlying thermal inhomogeneity reflects the existence of a topography. In the present work, this problem is investigated numerically through solution of the governing equations for mass, momentum and energy in their complete, three-dimensional time-dependent and non-linear form. Emphasis is given to a class of liquids for which thermal diffusion is expected to dominate over viscous effects (liquid metals). Fixing the Rayleigh and Marangoni number to 104 and 5 × 103, respectively, the sensitivity of the problem to the geometrical, kinematic and thermal boundary conditions is investigated parametrically by changing: the number and spacing of heating elements, their vertical extension, the nature of the lateral boundary (solid walls or periodic boundary) and the thermal behavior of the portions of bottom wall between adjoining elements (assumed to be either adiabatic or at the same temperature of the hot blocks). It is shown that, like the parent phenomena, this type of thermal flow is extremely sensitive to the specific conditions considered. The topography can be used to exert a control on the emerging flow in terms of temporal response and patterning behavior.


2021 ◽  
Author(s):  
Ramilla Vieira Assunção ◽  
Anne Lebourges-Dhaussy ◽  
Alex Costa da Silva ◽  
Bernard Bourlès ◽  
Gary Vargas ◽  
...  

Abstract. The use of active acoustic to monitor abiotic structures and processes in the ocean have been gaining ground in oceanography. In some systems, acoustics allow the robust estimation of the depth of the pycnocline or thermocline either directly or indirectly when the physical structures drive the one of organisms. Here, we examined the feasibility of extracting the thermohaline structure (mixed-layer depth, upper and lower thermocline) from echosounder data collected in the oligotrophic Southwestern tropical Atlantic region at two seasons (spring and fall), more precisely in two areas with different thermohaline conditions, at both day and night. For that, we tested three approaches: (i) the vertical extension of the epipelagic community; (ii) the use of acoustic gradients; and (iii) a cross-wavelet approach. Results show that, even if the thermohaline structure impacts the vertical distribution of acoustic scatters, the resultant structuring did not allow for a robust estimation of the thermohaline limits indicating that other oceanographic or biological processes are acting. This result prevents for a fine-scale representation of the upper-layer turbulence from acoustic data. However, studying the proportion of acoustic biomass within each layer provides interesting insights on ecosystem structure in different thermohaline, seasonal and diel scenarios.


Author(s):  
Sujan Pradhan ◽  
Yuebing Li ◽  
Yasushi Sanada

AbstractMany reinforced concrete (RC) frame buildings in Nepal were significantly damaged by the 7.8 magnitude (Mw) earthquake in Nepal on April 25, 2015. To contribute to mitigate future earthquake disasters, the current study focuses on two specific characteristics of residential RC frame buildings in the capital city of Nepal, Kathmandu: the application of brick masonry infill to exterior and partition walls, and the conventional vertical extension of building stories different from the design. Although these factors are likely to significantly affect the seismic performance, their effects are frequently neglected in practical design and construction management in developing countries. Hence, the main objective of this research is to investigate and clarify the seismic performance of RC frame buildings considering the above factors through experimental and numerical investigations. The present paper (1) briefly introduces the characteristics of a typical residential RC frame building in Kathmandu, (2) illustrates the numerical modeling parametrically considering three different contributions of brick masonry infill walls and (3) investigates the seismic performance of the RC frame building considering the effects of the infill wall modeling and the vertical extension through numerical analyses. Consequently, it was found that the consideration of the in-plane stiffness and strength of the infill walls resulted in both positive and negative contributions to the seismic performance of low-rise (up to three stories) and medium-rise (more than three stories) buildings respectively, quantitatively clarifying significant effects of the presence of infill and the vertical extension. These findings contribute to provide realistic solutions to upgrade the seismic performance by utilizing or removing the brick masonry infill walls or by managing the building stories to mitigate future earthquake disasters on typical RC frame buildings not only in Nepal but also in other countries with similar backgrounds.


2021 ◽  
Author(s):  
Alexander Caskey

<div>The default approach to building cities vertically is through the construction of towers. Such “common towers” multiply the “value” of a plot of ground by repeatedly stacking the most profitable types of private units vertically. These independent extrusions of land produce spaces that are disconnected from one another and the city below. The widespread proliferation of this default approach is rapidly filling the vertical territory of the world’s cities with privatized stacks of ordinary spaces.</div><div>A critical investigation of “Common Towers” and the conditions that have led to their proliferation exposes opportunities that their presence conceals. There is both architectural and urbanistic potential in the vertical territory above a city that cannot be realized through the “common tower.” This thesis explores the potential of the seamless vertical extension of the unconditionally public realm as a means of driving the three-dimensional organization of spaces within the volume of a city. <br></div>


2021 ◽  
Author(s):  
Alexander Caskey

<div>The default approach to building cities vertically is through the construction of towers. Such “common towers” multiply the “value” of a plot of ground by repeatedly stacking the most profitable types of private units vertically. These independent extrusions of land produce spaces that are disconnected from one another and the city below. The widespread proliferation of this default approach is rapidly filling the vertical territory of the world’s cities with privatized stacks of ordinary spaces.</div><div>A critical investigation of “Common Towers” and the conditions that have led to their proliferation exposes opportunities that their presence conceals. There is both architectural and urbanistic potential in the vertical territory above a city that cannot be realized through the “common tower.” This thesis explores the potential of the seamless vertical extension of the unconditionally public realm as a means of driving the three-dimensional organization of spaces within the volume of a city. <br></div>


ce/papers ◽  
2021 ◽  
Vol 4 (2-4) ◽  
pp. 2425-2433
Author(s):  
Charles Gillott ◽  
Danielle Densley‐Tingley ◽  
Buick Davison

2021 ◽  
Vol 25 (1) ◽  
pp. 89-100
Author(s):  
M Nasim ◽  
A Khatun ◽  
MJ Kabir ◽  
ABM Mostafizur ◽  
MAA Mamun ◽  
...  

Unavailability of suitable technologies including stress-tolerant cultivars, management options, irrigation facilities as well as extension supports are the key challenges for intensification of cropping through horizontal and vertical extension approaches. This study assesses the potential for increasing rice production through a horizontal extension approach. Historical and projected trend of area and production of rice, major cropping patterns and cropping intensity, as well as expert opinion, were the basis for extrapolation of the intensity of cropping by 2030. The analysis shows that about 1.52 M ha area with fallow period of the existing major cropping patterns and 0.65 M ha fallow land is potential for additional rice cropping. Resulting from that about 5.8 million tons additional rice can be added to total rice production in the country. An inclusion of a rice crop in certain percentage of the existing major cropping patterns, such as Boro-Fallow-T. Aman (25%), Boro-Fallow-Fallow (50%) and Fallow-Fallow-T. Aman (40%) may contribute, respectively 1.38 million tons, 1.57million tons and 0.80 million tons of rice in the total rice production. Besides, the addition of a certain percentage of cultural waste (50%), marshy land (25%), newly developed char land (50%), and Jhum (60%) and other extrapolation areas of Chittagong Hill Tract, respectively may contribute 0.4 million tons, 0.25 million tons, 0.34 million tons and 0.06 million tons rice in the total rice production. Strategic policy supports are required for implementing appropriate action plans to achieve the goals. Bangladesh Rice J. 25 (1) : 89-100, 2021


2021 ◽  
Vol 13 (7) ◽  
pp. 3647
Author(s):  
Soo-Yeon Seo ◽  
Byunghee Lee ◽  
Jongsung Won

Remodeling underground structures requires careful construction planning, including consideration of costs and scheduling. Therefore, this study aims to analyze and compare the effects of four methods for vertically extending the underground spaces of an existing building under scheduling and cost constraints. The study considers the following extension methods: (1) bottom-up method, (2) normal top-down method after demolition, (3) normal top-down method in parallel with demolition, and (4) top-down method using double beams in parallel with demolition. Twelve illustrative examples are presented to investigate the constructability of these methods in terms of construction scheduling and costs. The construction durations and costs of each example is calculated and compared. We also analyze the structural stability of the examples using MIDAS Gen 2017. We conclude that the top-down method using double beams is the most efficient method in terms of costs and scheduling. The results and analysis process can help practitioners to select appropriate methods to expand underground spaces without demolishing entire existing buildings and efficiently manage costs and schedules. In future studies, these extension methods should be applied to real-world projects in various countries to validate and verify their actual effects on construction costs and scheduling.


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