rectangular shape
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2022 ◽  
Vol 789 ◽  
Author(s):  
Bruna Maria Silva Cavalcante ◽  
Kjell Arne Johanson

Oxyethira Eaton, 1873 is one of the most diverse genera of Hydroptilidae, comprising over 240 species distributed in all biogeographical regions. Here three new species of Oxyethira (Trichoglene) Neboiss, 1977 are described and illustrated from male specimens collected in New Caledonia: O. (Trichoglene) hamus sp. nov., recognized by the hook-shaped apex of the long inferior appendages in lateral view and by the posterior margin of segment IX with a trilobed appearance in ventral view; O. (Trichoglene) rectangulata sp. nov., recognized by the rectangular shape of the inferior appendages, which are totally fused and with two pairs of small setae on the inner face; and O. (Trichoglene) spiralis sp. nov., recognized by the strongly curvilinear shape of the subgenital process in dorsal and lateral views and by the long process spiralling around the ejaculatory duct at the phallus apex.


Archaeology ◽  
2021 ◽  
pp. 66-81
Author(s):  
Serhii Ryzhov ◽  
◽  
Valentyna Shumova ◽  

The Trypillia settlement is located at the western edge of Hlybochok village (former Zvenyhorodka district of Cherkasy Oblast), at the plateau of the western bank of the Hirskyi Tikych River. According to the geophysical surveys, the settlement size reached 100 ha. Its dwellings were organized into two ellipses. The remains of two dwellings (ploshchadki) were excavated in 1994—1995. Ploshchadka No. 1 was located in the southern part of the external construction ellipse, while ploshchadka No. 2 was located in the second internal ellipse at the eastern part of the site. The remains of both houses had a rectangular shape and included several layers of burnt clay. Houses had fireplaces on the lower storey. The second house also included an elevation of rectangular shape with grinding stones. Living areas are associated with the upper storey of houses. The majority of materials, mainly kitchen and table pottery, were found between the layers of burnt clay. Kitchen pottery (6—7 %) is represented by conical bowls and pots with S-shaped profiles with poor ornamentation. Table pottery (92—93 %) is represented by ceramics ornamented with black monochromic painting. Nearly 45 % of pottery forms and 25 % of ornamentation schemes were reconstructed. Ceramic shapes are represented by bowls, goblets, biconical, spherical and conical vessels, amphorae, pear-shaped vessels, leads, craters, pots and binocular-shaped vessels. Anthropomorphic figurines were found in fragments. The Hlybochok settlement is referred to the late phase of Nebelivska group (the end of BII period) of the development of the Western Trypillia culture. The settlement is dated to the range of 3925—3825 BC. The Nebelivska group marks the migration of the Western Trypillia culture populations to the north-eastern direction, towards the Middle Dnieper region. Its further development between the Ros and the Dnieper rivers resulted in the formation of Kanivska local group, which pottery is also characterized by the influence of the Eastern Trypillia traditions. In the indigenous area the Nebelivska local group was replaced by the Tomashivska group.


Author(s):  
A. V Cherepkov ◽  
I. V. Konoshin

Grain before feeding to animals exposed to grinding with the purpose of increasing its digestibility. As a result of this increases the area of interaction of the feed with the gastric juice and decreases the conversion coefficient. Surface theory formulated by German scientist Rittinger, suggests that the work of AR required for the grinding process is directly proportional to newly formed surface. The purpose of this paper is a theoretical evaluation of the intensity of grinding with the use of sieves with rectangular and circular shape holes. When getting groats with the same grinding module by the use of sieves with holes of rectangular shape, one should expect the decrease of specific energy intensity. By reducing the content of dust-like fractions and reduce the total surface feed should be expected to reduce the energy intensity of pneumo transportation.


2021 ◽  
Vol 25 (12) ◽  
pp. 10-14
Author(s):  
R.Ya. Bikkulov ◽  
O.S. Dmitrieva ◽  
A.V. Dmitriev ◽  
G.R. Badretdinova

To solve the problem of increasing the efficiency of cleaning the exhaust air of painting chambers from fine particles, a separation device with elements of a square and rectangular shape has been developed and described by the principles of its operation. A method for calculating the design dimensions of the developed separation device is presented. Different versions of the height of the separation zone are considered, depending on the size of dispersed particles. It is shown that the device is able to capture particles smaller than 10 microns with an efficiency close to 100 %, provided they adhere to the walls. The peculiarity of the design of the separation device is that a set of small-diameter vortices is created, in which the flow regime is close to laminar, and to achieve large values of centrifugal force, it is not necessary to create high speeds in the crevices.


2021 ◽  
Vol 2 (2) ◽  
pp. 1-3
Author(s):  
Víctor Marcelo

Spain’s National Network of Silos and Granaries building a total de 665 silos and 285 granaries. 20 different typologies of silos were built, highlighting type D over all of them with a total of 389 units. This typology prolonged its construction for 34 years, appearing several subtypes (D1, D2, D3 D4 y D5). The Manganese of the Lampreana silo (Zamora) is a D5 type silo with 3,350 t of storage capacity, distributed in 24 storage tanks called cells, built in 1968. Architecturally speaking it is a simple and powerful silo. It has a rectangular shape, made up of three rows of square cells, the outer rows of cells rested directly on the ground storey floor and the center row is raised. Front tower between two cells, being embedded between them in a central position, achieving a compact and robust volume. The structure is made up of reinforced concrete pillars at the corners of the cells and the cell walls of reinforce bricks. Technologically speaking it has many similarities with its predecessors, types A and B. Here the elevator receives the grain directly from the reception hopper raising wheat and emptying it onto an upper horizontal belt conveyor, where dampers motorized valves, it is distributed across other tubes to one of the three cells in each bay. The grain is unloaded onto lower horizontal belt conveyors lying at different heights. From there it is carried to a raised cell for bulk offloading onto a lorry.


2021 ◽  
pp. 002199832110572
Author(s):  
Andreas Tsiantis ◽  
Yanwei Wang ◽  
Xianbo Huang ◽  
TD Papathanasiou

We present a comprehensive computational and theoretical analysis of diffusion through flake composites in which the flakes are of rectangular shape, spanning the entire spectrum from squares to ribbons. Following a large number of detailed 3D simulations in realistic Representative Volume Elements (RVEs), each containing 1000s of individual flakes, we propose a scaling which, for the first time in the technical literature, introduces the planar aspect ratio r of the flakes as a parameter affecting the barrier properties of the resulting composite. Subsequently, we examine the effect of r in several cases of practical significance, such as under the assumptions of (i) constant number-density N/Δ V and flake volume fraction ϕ, (ii) constant N/Δ V and flake diagonal and (iii) constant ϕ and varying N/Δ V—describing the problem of the fragmentation of ribbons into flakes. Both deterministic and stochastic systems in terms of r, are considered. One key result is that square flakes offer the best barrier performance compared to flakes of general rectangular shape—as long as N/Δ V and ϕ or the diagonal of the flakes remain constant. Randomness in flake aspect ratio only moderately impacts the barrier improvement factor as long as ϕ and N/Δ V remain constant but has a strong effect under the assumption of constant N/Δ V and flake diagonal. Finally, we show that, for r < 10 and M < 1, the scaling proposed in this work is valid not only for unidirectional flakes but also for flakes showing random in-plane orientations.


2021 ◽  
Vol 2070 (1) ◽  
pp. 012181
Author(s):  
P M Wadekar ◽  
A B Shinde ◽  
V B Patil ◽  
P D. Kulkarni ◽  
P V Kengar ◽  
...  

Abstract Nowadays a lot of interest is given to the geometrical modification of heat sink systems to cool down the electronic components. To improve the performance index of the heat sinks, the use of geometrical features with different shapes and at different locations on the surface can be a valuable approach. In this paper, the effect of rectangular shape obstacles on the micro channel heat sink (MCHS) performance is studied. Due to surface features, vortex is developed which helps to increase the heat transfer rate. Numerical modeling software Comsol Multiphysics with heat transfer in fluid physics is used to investigate the characteristics of a micro-channel heat sink. The numerical result shows that the heat transfer rate can be improved through an appropriate arrangement of rectangular shape obstacles, on the heat sink. Numerical analysis and the comparison is carried out for micro-channel heat sink with and without obstacles. In this paper, various parameters like temperature rise, cell Peclet number and Mean effective thermal conductivity are studied.


2021 ◽  
Vol 926 (1) ◽  
pp. 012040
Author(s):  
A Indriawati ◽  
R Sari ◽  
Sulanjari

Abstract The development of spintronic devices in the magnetic memories industry has attracted researchers over decades. Therefore, researchers are trying to obtain materials which compatible to improve device performance. These materials are made in the form of thin layer. Cerium-iron-boron (Ce-Fe-B) alloy is one of potential materials to be applied for magnetic devices. In this study, the nucleation changes in the Ce-Fe-B thin layer were analyzed using circular and rectangular shapes. This phenomenon was observed through micromagnetic simulations. The magnetic moment stability of Ce-Fe-B was analyzed based on the response of the magnetic moment towards the presence of an external magnetic field. The magnitude of applied external magnetic applied is 0.4 Tesla in x-axis direction. Changes in the arrangement of magnetic moments due to external magnetic fields produce magnetization and anisotropy energy value which describing the characteristics of the Ce-FeB thin layer. Magnetization value of Ce-Fe-B thin film in circular shape was greather than rectangular shape. These value was 0.98 for circular shape and 0.93 for rectangular shape. On the other hand, anisotropy energy value on magnetic external apllied 400 mT, circular shape anisotropy energy’s value of Ce-Fe-B was 4.85×10-18 J, and 6.71×10-18 J for rectangular shape.


2021 ◽  
Vol 13 (3) ◽  
pp. 276-279
Author(s):  
G. Tihanov ◽  
G. Hristova

Abstract. A study has been conducted for some operational indicators of a machine-tractor unit (MTU) for direct sowing of barley. The data for this study has been collected and retrieved by using the JD Link telematics system from two different fields sown with barley: field A with irregular shape and area of 13.75 ha and field B with rectangular shape and area of 16.26 ha. It was found that for both fields the values for the most monitored parameters were very close as follows: for the engine speed of the sowing unit during working stroke – 1553.65 min-1 (A) and 1586.11 min-1 (B) (the difference is <2.08%); for the idle mode of the sowing unit – 900.08 min-1 (A) and 905.63 min-1 (B) (the difference is <0.62%); for the actual working speed – 9.97 km/h (А) and 10.16 km/h (В) (the difference is <1.9%), registered when the MTU is performing the technological operation “sowing”; those parameters of MTU are nor influenced by the field size and shape. Larger differences in values between the two fields were established in terms of the relative share of engine used – 19.98% (A) and 21.55% (B) (the difference is <7.3%) and for the consumed diesel fuel (in field А it was 7.2% liters higher than in field В, respectively, 11.7% higher referring to the average diesel fuel consumption – liters per hour). The actual hourly productivity in field A was 20% lower than in field B – 3.05 vs 3.81, which is due to the fact that in the field with irregular shape – A the sowing unit made more turns at the end of the levels than in the field with rectangular shape – B.


Author(s):  
Espanta Ferdowsian

Flow inside a rectangular shape nozzle is simulated in this study. Finite volume scheme is utilized as the main solver for the current study. Second order scheme is utilized to discretize pressure. Second order upwind scheme is utilized for solving momentum equation. Then the momentum equation is coupled with the continuity equation to obtain the pressure and velocity at each cell. Cavitation inception and super cavitation is also found and discussed in this study and the results were also verified with previous Winklhofer et al. experiments.


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