Optimal Orthogonal Subdivision of Rectangular Sheets

1996 ◽  
Vol 118 (3) ◽  
pp. 281-288 ◽  
Author(s):  
M. Shpitalni ◽  
V. Manevich

The two-dimensional problem of optimal orthogonal subdivision of rectangular sheets (stock cutting) is of great interest to industry. In this paper, a new model is presented which formulates the problem in terms of integer linear programming (ILP). Using this new model, three objective functions dealing with important practical applications are formulated and demonstrated. They are: (i) selection and placement, including orientation, of rectangles on a given (single) sheet, while minimizing the unused (scrap) material; (ii) grouping the rectangles together in a predicted form, leaving a “good” and predetermined unused part of the sheet in cases where all the rectangles can be placed on a single sheet; and, (iii) optimal arrangement of rectangles on multiple sheets, including selection of the sheets to be used.

The boundary integral equations of potential theory can be solved to a tolerable accuracy without undue labour by digital computer techniques, and the computed datagenerate numerical values of the potential field wherever required. Tests have been made with a representative selection of two-dimensional problem s, some of which would not be amenable to any other treatment.


2020 ◽  
Vol 39 (5) ◽  
pp. 6339-6350
Author(s):  
Esra Çakır ◽  
Ziya Ulukan

Due to the increase in energy demand, many countries suffer from energy poverty because of insufficient and expensive energy supply. Plans to use alternative power like nuclear power for electricity generation are being revived among developing countries. Decisions for installation of power plants need to be based on careful assessment of future energy supply and demand, economic and financial implications and requirements for technology transfer. Since the problem involves many vague parameters, a fuzzy model should be an appropriate approach for dealing with this problem. This study develops a Fuzzy Multi-Objective Linear Programming (FMOLP) model for solving the nuclear power plant installation problem in fuzzy environment. FMOLP approach is recommended for cases where the objective functions are imprecise and can only be stated within a certain threshold level. The proposed model attempts to minimize total duration time, total cost and maximize the total crash time of the installation project. By using FMOLP, the weighted additive technique can also be applied in order to transform the model into Fuzzy Multiple Weighted-Objective Linear Programming (FMWOLP) to control the objective values such that all decision makers target on each criterion can be met. The optimum solution with the achievement level for both of the models (FMOLP and FMWOLP) are compared with each other. FMWOLP results in better performance as the overall degree of satisfaction depends on the weight given to the objective functions. A numerical example demonstrates the feasibility of applying the proposed models to nuclear power plant installation problem.


1996 ◽  
Vol 8 (3) ◽  
pp. 133-144 ◽  
Author(s):  
María del Mar del Pozo Andrés ◽  
Jacques F A Braster

In this article we propose two research techniques that can bridge the gap between quantitative and qualitative historical research. These are: (1) a multiple regression approach that gives information about general patterns between numerical variables and the selection of outliers for qualitative analysis; (2) a homogeneity analysis with alternating least squares that results in a two-dimensional picture in which the relationships between categorical variables are graphically presented.


2016 ◽  
Vol 11 (1) ◽  
pp. 119-126 ◽  
Author(s):  
A.A. Aganin ◽  
N.A. Khismatullina

Numerical investigation of efficiency of UNO- and TVD-modifications of the Godunov method of the second order accuracy for computation of linear waves in an elastic body in comparison with the classical Godunov method is carried out. To this end, one-dimensional cylindrical Riemann problems are considered. It is shown that the both modifications are considerably more accurate in describing radially converging as well as diverging longitudinal and shear waves and contact discontinuities both in one- and two-dimensional problem statements. At that the UNO-modification is more preferable than the TVD-modification because exact implementation of the TVD property in the TVD-modification is reached at the expense of “cutting” solution extrema.


Nanophotonics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 2125-2145 ◽  
Author(s):  
Lu Ming Dong ◽  
Cui Ye ◽  
Lin Lin Zheng ◽  
Zhong Feng Gao ◽  
Fan Xia

AbstractTransition metal carbides and nitrides (MXenes), which comprise a rapidly growing family of two-dimensional materials, have attracted extensive attention of the scientific community, owing to its unique characteristics of high specific surface area, remarkable biocompatibility, and versatile applications. Exploring different methods to tune the size and morphology of MXenes plays a critical role in their practical applications. In recent years, MXenes have been demonstrated as promising nanomaterials for cancer therapy with substantial performances, which not only are helpful to clarify the mechanism between properties and morphologies but also bridge the gap between MXene nanotechnology and forward-looking applications. In this review, recent progress on the preparation and properties of MXenes are summarized. Further applications in cancer therapy are also discussed. Finally, the current opportunities and future perspective of MXenes are described.


2014 ◽  
Vol 18 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Johanna C Gerdessen ◽  
Olga W Souverein ◽  
Pieter van ‘t Veer ◽  
Jeanne HM de Vries

AbstractObjectiveTo support the selection of food items for FFQs in such a way that the amount of information on all relevant nutrients is maximised while the food list is as short as possible.DesignSelection of the most informative food items to be included in FFQs was modelled as a Mixed Integer Linear Programming (MILP) model. The methodology was demonstrated for an FFQ with interest in energy, total protein, total fat, saturated fat, monounsaturated fat, polyunsaturated fat, total carbohydrates, mono- and disaccharides, dietary fibre and potassium.ResultsThe food lists generated by the MILP model have good performance in terms of length, coverage and R2 (explained variance) of all nutrients. MILP-generated food lists were 32–40 % shorter than a benchmark food list, whereas their quality in terms of R2 was similar to that of the benchmark.ConclusionsThe results suggest that the MILP model makes the selection process faster, more standardised and transparent, and is especially helpful in coping with multiple nutrients. The complexity of the method does not increase with increasing number of nutrients. The generated food lists appear either shorter or provide more information than a food list generated without the MILP model.


2001 ◽  
Vol 124 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Eduardo A. Rinco´n ◽  
Fidel A. Osorio

A new two-dimensional concentrator for solar energy collection has been developed. The concentrator has the following advantages, when compared with the classic Compound Parabolic Concentrators invented by Roland Winston, W. T. Welford, A. Rabl, Baranov, and other researchers: 1) It allows the use of parabolic mirrors, which have a reflecting area much smaller for a given concentration ratio and acceptance angle. 2) Between the mirror and the absorber, there is a large gap so that conduction losses are reduced. Convection losses can be reduced, too, if the absorber is enclosed within a glass tube. 3) It can be easily manufactured. Instead of seeking the shape of the mirrors for a given shape of the absorber, we have made the inverse statement of the problem, and we have obtained the optimal shapes of the absorbers with a prescribed acceptance angle, for parabolic mirrors, assuming that the intercept factor is unity, the mirrors are perfect, and the absorber surfaces are convex. The concentrator should be east-west oriented, and could be seasonal or monthly tilt adjusted. This concentrator could have many practical applications, such as fluid heating, steam generation, etc.


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