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OR Spectrum ◽  
2021 ◽  
Author(s):  
Herbert Meyr ◽  
Mirko Kiel

AbstractA real-world planning problem of a printing company is presented where different sorts of a consumer goods’ label are printed on a roll of paper with sufficient length. The printer utilizes a printing plate to always print several labels of same size and shape (but possibly different imprint) in parallel on adjacent lanes of the paper. It can be decided which sort is printed on which (lane of a) plate and how long the printer runs using a single plate. A sort can be assigned to several lanes of the same plate, but not to several plates. Designing a plate and installing it on the printer incurs fixed setup costs. If more labels are produced than actually needed, each surplus label is assumed to be “scrap”. Since demand for the different sorts may be heterogeneous and since the number of sorts is usually much higher than the number of lanes, the problem is to build “printing blocks”, i.e., to decide how many and which plates to design and how long to run the printer with a certain plate so that customer demand is satisfied with minimum costs for setups and scrap. This industrial application is modeled as an extension of a so-called job splitting problem which is solved exactly and by various decomposition heuristics, partly basing on dynamic programming. Numerical tests compare both approaches with further straightforward heuristics and demonstrate the benefits of decomposition and dynamic programming for large problem instances.


2021 ◽  
Vol 11 (24) ◽  
pp. 12024
Author(s):  
Tengfei Zhao ◽  
Hong Yan ◽  
Panpan He ◽  
Lei Zhang ◽  
Zhiwen Lan ◽  
...  

Transmission tower connection joint is an important connection component of the tower leg member and diagonal member. Its axial stiffness directly affects the stable bearing capacity of a transmission tower. The axial stiffness of the joint is mainly related to the connection form of joint. This paper takes the double-limb double-plate connection joint as the research object. Through the comparative study with the single-limb single-plate connection joint, the influence law of single-limb single-plate and double-limb double-plate joint on stable bearing capacity of quadrilateral transmission tower is studied from three aspects of model test, theoretical analysis and numerical simulation. Through the scale model test, it is found that the elastic stiffness of the double-limb double-plate joint is 3.12 times that of the single-limb single-plate joint, which can increase the bearing capacity of the joint by 26.1%. Through the energy method, the theoretical calculation expression of the stable bearing capacity of the quadrilateral tower considering the influence of the axial stiffness of the joint is derived. Compared with the effect of the single-limb single-plate connection joint, the double-limb double-plate joint can improve the stable bearing capacity of the quadrilateral tower by 15.6%. Considering the influence of geometric nonlinearity of tower and connecting joint, it is found that the double-limb double-plate connecting joint can improve the nonlinear stability bearing capacity of a transmission tower by 14.9%. The results show that the double-limb double-plate connection joint can not only improve the bearing capacity of the joint, but also greatly improve the stable bearing capacity of the tower. The research results can provide reference for the engineering application and design of double-limb double-plate connection joints.


Author(s):  
B. Gowthama Rajan ◽  
S. Padmanabhan ◽  
K.V. Mani Prathap ◽  
U.V. Satya Prasad ◽  
G. Pavan Kumar

2021 ◽  
Author(s):  
◽  
Amandine Chambord

<p>Quantifying past motions of tectonic plates in the southwest Pacific is important because the Pacific-Antarctic ridge is the only non-destructive boundary between the Pacific plate and other major plates. However, formation of sea-ice near Antarctica impairs the collection of magnetic anomaly data that are necessary to calculate plate rotations. A detailed analysis of all ship-track magnetic data available in the southwest Pacific (61 cruises, 153 profiles, including several cruises collected after 1995) is presented here. Four different sources of uncertainty are quantified: (1) confidence of magnetic anomaly identification, (2) magnetic reversal location picking precision, (3) ship navigation precision, and (4) magnetic data quality. Finite plate rotations are calculated for the southwest Pacific (42.5 to 79 Ma) using the resulting magnetic anomaly database (1528 magnetic reversal data). Finite rotations were calculated using the Hellinger criterion, or by a new method presented here that assumes orthogonality between fracture zones and ridge segments. The new method requires less parameters and is hence able better estimate rotations in cases with an uneven distribution of sparse magnetic data. Rotations and formal uncertainties are calculated for thirty-one chrons (c20y to c33o). They confirm the existence of a three plate system (Pacific, Marie Byrd Land, Bellingshausen) in the southwest Pacific from before c31o (68.7 Ma) until c28y (62.5 Ma). After c28y, the Bellingshausen and Marie Byrd Land plates moved as a single plate.</p>


2021 ◽  
Author(s):  
◽  
Amandine Chambord

<p>Quantifying past motions of tectonic plates in the southwest Pacific is important because the Pacific-Antarctic ridge is the only non-destructive boundary between the Pacific plate and other major plates. However, formation of sea-ice near Antarctica impairs the collection of magnetic anomaly data that are necessary to calculate plate rotations. A detailed analysis of all ship-track magnetic data available in the southwest Pacific (61 cruises, 153 profiles, including several cruises collected after 1995) is presented here. Four different sources of uncertainty are quantified: (1) confidence of magnetic anomaly identification, (2) magnetic reversal location picking precision, (3) ship navigation precision, and (4) magnetic data quality. Finite plate rotations are calculated for the southwest Pacific (42.5 to 79 Ma) using the resulting magnetic anomaly database (1528 magnetic reversal data). Finite rotations were calculated using the Hellinger criterion, or by a new method presented here that assumes orthogonality between fracture zones and ridge segments. The new method requires less parameters and is hence able better estimate rotations in cases with an uneven distribution of sparse magnetic data. Rotations and formal uncertainties are calculated for thirty-one chrons (c20y to c33o). They confirm the existence of a three plate system (Pacific, Marie Byrd Land, Bellingshausen) in the southwest Pacific from before c31o (68.7 Ma) until c28y (62.5 Ma). After c28y, the Bellingshausen and Marie Byrd Land plates moved as a single plate.</p>


2021 ◽  
Author(s):  
Dae Jin Nam ◽  
Min Seok Kim ◽  
Tae Ho Kim ◽  
Min Woo Kim ◽  
Suc Hyun Kweon

Abstract Introduction: We evaluated the radiologic and clinical outcomes of a lateral incision single plate with and a single-incision double plating in elderly patients with osteoporotic distal femoral fractures.Materials and Methods: We performed a retrospective study of 82 cases of distal femoral fractures from May 2004 to June 2018. Group A consisted of 42 patients who underwent single-plate fixation. Group B consisted of 40 patients who underwent double-plate fixation. The mean patient age was 77 years (67–87 years) and 76 years (64–86 years) in groups A and B, respectively. All patients were evaluated for procedure duration, time to union, range of knee motion, Lysholm knee score, and presence of complications.Results: The average procedure time was 81 min (66–92 min) and 110 min (95–120 min) in groups A and B, respectively(p=0.33). One case in group B required bone grafting after 5 months. The average time to union was 14 weeks (9–19 weeks) and 12.2 weeks (8–19 weeks) (p=0.63), and the mean range of knee motion was 105° (90–125°) and 110.7° (90°–130°) (p=0.37) in groups A and B, respectively. There was no significant statistical difference between the two groups in the Lysholm knee score(p=0.44) and knee society score(p=0.53).Conclusion: The clinical and radiological outcomes were similar in the 2 groups. In elderly patients, double plate fixation for distal femoral fractures is an useful method for several advantages such as adequate exposure, easy manipulation, anatomical reduction and stable fixation.


Author(s):  
Wenqi Ding ◽  
Dong Zhou ◽  
Xiaoqing Chen ◽  
Chao Duan ◽  
Qingzhao Zhang

Grouting reinforcement was used to improve rock strength and avoid seepage in rock engineering. A self-developed visualised test platform was developed and the influences of different fracture openness on grouting diffusion modes were revealed; the Bingham rheological model was imported to simulate the grouting diffusion process in a single plate fracture, the spatio-temporal distribution of the velocity field under different obstructions was determined using the finite element method. The results indicate that: 1) The grout diffuses faster with the increase of fracture openness, while a stagnation effect of the grouting diffusion velocity behind the obstruction occurs. 2) Due to obstructions, the grouting diffusion process can be divided into four stages: circular diffusion, flat diffusion, vortex diffusion, and butterfly diffusion. 3) The grouting diffusion area is divided into a fully-reinforced zone and a semi-reinforced zone, and the area of the latter increases with the fracture openness, while being little affected by the size of any obstruction. 4) Furthermore, some new grouting diffusion laws were revealed considering the asymmetrical arrangement of obstructions. The results presented in this work will be helpful for describing and predicting the grouting process in fracture networks.


Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1757
Author(s):  
Kanishk Rauthan ◽  
Ferdinando Guzzomi ◽  
Ana Vafadar ◽  
Kevin Hayward ◽  
Aakash Hurry

Passive heat exchangers (HXs) form an inseparable part of the manufacturing industry as they provide high-efficiency cooling at minimal overhead costs. Along with the aspects of high thermal cooling, it is essential to monitor pressure loss while using plate-fin HXs because pressure loss can introduce additional power costs to a system. In this paper, an experimental study was conducted to look at the effects of dimples on the pressure drop characteristics of single plate-fin heat exchangers. To enable this, different configurations of National Advisory Committee for Aeronautics (NACA) fins with smooth surfaces and 2 mm-diameter dimples, 4 mm-diameter dimples and 6 mm-diameter dimples were designed and 3D printed using fused deposition modelling (FDM) of ABS plastic. The depth to diameter ratio for these dimples was kept constant at 0.3 with varied diameters and depths. These were then tested using a subsonic wind tunnel comprised of inlet and outlet pressure taps as well as a hot wire velocimeter. Measurements were taken for pressure differences as well as average velocity. These were then used to calculate friction factor values and to compare the smooth fin to the dimpled fins in relation to their relative pressure drop performance. It was observed that for lower velocities the 4 mm dimples provided minimum pressure drop, with a difference of 58% when compared to smooth fins. At higher velocities, 6 mm dimples increased the pressure drop by approximately 34% when compared to smooth fins. It can also be concluded from the observed data in this study that shallower dimples produce lower pressure drops compared to deeper dimples when the depth to diameter ratio is kept constant. Accordingly, deeper dimples are more effective in providing drag reduction at lower velocities, whereas shallower dimples are more effective for drag reduction at higher velocities.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6509
Author(s):  
Agnieszka Malec ◽  
Tomasz Cholewa ◽  
Alicja Siuta-Olcha

Domestic hot water preparation is one of the main sources of energy consumption in households. One of the most important elements of domestic hot water (DHW) preparation installation is the storage tank. Its design can significantly affect the efficiency of the system and energy consumption for hot water preparation. This paper presents the results of an experimental study to examine seven different designs of the cold water inlet to the storage tank and the use of two types of obstacles inside this tank placed at three different heights. The number of stratification and the energy efficiency of the system for each variant were examined. Additionally, tests were carried out for different profiles of hot water consumption in order to examine the temperature changes in the DHW tank. A system with an inlet, as an elbow facing down with a single plate, turned out to be the most advantageous variant (3–8% increase in energy efficiency compared to the basic inlet variant). An analogous analysis of the use of obstacles inside the tank showed that the most optimal solution is to place the partition, which allows the water flow on the sides of the tank, in its lower parts (energy efficiency higher by up to 15% compared to the variant without a partition). These solutions showed the highest energy efficiency for DHW production and the lowest energy demand for hot water heating in the tank among all analyzed variants.


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