25,339 research outputs found
Characterization of graphite polyurethanes composite from renewable based oils
This thesis aims to evaluate the characterization of graphite polyurethane composite
from renewable based oils. Virgin cooking oil (VCO) as a renewable resource is the
main substance in fabricating the renewable polyurethane (PU) and its graphite as
called polyurethane graphite (PG). The fabricating sample have two methods that is
open casting and heat press method. PU and PG with different percentage of graphite
as filler were investigated for structural, morphological, physical and mechanical
properties that going through a several testing including Optical Microscope (OM),
Scanning Electron Microscope (SEM), Ultraviolet-visible (UV-Vis), Fourier
Transform Infrared (FT-IR), Density Test, Tensile test and cross-link density. The
renewable polyurethane is namely as PU and polyurethane graphite is namely as
PG2, PG4, PG6, PG8, PG10 with subscript numbers indicate the weight loading of
graphite content was varied in the renewable polyurethane from 2, 4, 6, 8, and
10wt%. The result of SEM and OM showed that the graphite particles are randomly
distributed and homogeneously scattered well in the PU due to interconnected
interface within the matrix of polymeric composites. UV- Vis technique is used to
characterize the absorption, transmission and reflectivity of the PU and PG’s
otherwise the FT-IR is used for determine the composition and characterize the
polymer structure of PU and PG’s. As expected, the mechanical properties of
composites proven that the addition of graphite can change the matrix properties of
PU to improve modulus and consequent lowered the tan delta with respected of
increasing the temperature. The calculated cross-linked density of PU and PG
composites revealed the increment of graphite particle loading gives highest result of
cross-linking and this is due to the PG10 is the highest graphite content and the
highest value of storage modulus, highest value of tensile strength and the highest
value of young modulus. Therefore, the result shows the renewable polymer graphite
composite is suitable to be used in various composites applications
Linear Programming for a Cutting Problem in the Wood Processing Industry – A Case Study
In this paper the authors present a case study from the wood-processing industry. It focuses on a cutting process in which material from stock is cut down in order to provide the items required by the customers in the desired qualities, sizes, and quantities. In particular, two aspects make this cutting process special. Firstly, the cutting process is strongly interdependent with a preceding handling process, which, consequently, cannot be planned independently. Secondly, if the trim loss is of a certain minimum size, it can be returned into stock and used as input to subsequent cutting processes. In order to reduce the cost of the cutting process, a decision support tool has been developed which incorporates a linear programming model as a central feature. The model is described in detail, and experience from the application of the tool is reported.one-dimensional cutting, linear programming, wood-processing industry
Notes and laboratory reports on “Technology of Structural materials and Material Science” Part 2
“Technology of Structural materials and Material Science” is one of the basic technical disciplines in the syllabus for “Engineering mechanics” field of study.
During the implementation of laboratory work considerable attention is given to the educational and experimental work for the study of materials that are used in different branches of an industry; alloy’s properties dependance on the chemical composition; structure, methods of treatment and external environments. The study of the theory and practice of different methods of materials strengthening is to provide a high reliability and longevity of the machine’s details, devices, tools etc.
After every practical class in the laboratory, students will fill the laboratory report. The content of the laboratory class corresponds with the syllabus of the course “Material Science” for students of the “Engineering mechanics” field of study.
The purpose of this manual is to provide guidelines for the students in preparation for independent laboratory work and to project its results in the laboratory reports
One-Dimensional Cutting Stock Optimisation by Suborders
This paper introduces a method for solving a one-dimensional cutting stock problem by suborders. The method is used for large orders that for technological and logistical reasons cannot be filled in a single order, but only in several successive suborders. The method has two stages. In the first stage, the suborders are generated and in the second the trim-loss is minimised. All leftovers longer than D are returned to stock and reused. Shorter leftovers are treated as trim-loss and discarded. A detailed description of the method is provided by using a practical case. The method is tested by solving 108 randomly generated problem instances
Evaluation of Procurement Scenarios in One-Dimensional Cutting Stock Problem with a Random Demand Mix
The one-dimensional cutting stock problem describes the problem of cutting standard length stock material into various specified sizes while minimizing the material wasted (the remnant or drop as manufacturing terms). This computationally complex optimization problem has many manufacturing applications. One-dimensional cutting stock problems arise in many domains such as metal, paper, textile, and wood. To solve it, the problem is formulated as an integer linear model first, and then solved using a common optimizer software. This paper revisits the stochastic version of the problem and proposes a priority-based goal programming approach. Monte Carlo simulation is used to simulate several likely inventory order policies to minimize the total number of shortages, overages, and the number of stocks carried in inventory
A pattern enumeration approach to the trim loss problem
This thesis examines the characteristics of practical one dimensional trim loss problems. As a result of the wide range of these characteristics, previous scheduling methods have only had a limited range of applicability. A heuristic approach is proposed, based on pattern enumeration, which can be used to develop scheduling methods for a reasonably wide class of trim loss problems. The effectiveness of the approach depends on its ability to avoid the intractable residual problems which normally arise towards the end of a heuristic scheduling procedure. The approach is used in three case studies, and the efficiency of the schedules generated is compared with that yielded by other methods
- …