Elements and Materials Improve the FDM Products: A Review

2016 ◽  
Vol 16 ◽  
pp. 33-51 ◽  
Author(s):  
Abduladim Salem Bala ◽  
Saidin bin Wahab ◽  
Mazatusziha binti Ahmad
Keyword(s):  
Matrix Material ◽  
Process Parameter ◽  
Correct Selection ◽  
Complex Environment ◽  
Technology Process ◽  
The Matrix ◽  
Additive Materials ◽  
Insight Into ◽  
Selection Of

This work aims to provide a review of available published literature that explores the opportunities to improve the quality of fused deposit modelling (FDM) products, particularly in medical applications. The paper presents details concerning the basis of the technology, process parameter settings and their responses, and reviews the properties of common FDM engineering/bio-materials and the available methods applied for improving their performance. Based on the researches which have been reviewed, FDM technology works within a complex environment from process parameters. Thus, it can achieve good results only with the proper settings for these parameters according to the properties of the material used. Improving the polymers is essentially based on the correct selection of additive materials, which can particularly enhance the key property/properties in the matrix material. This review provides a brief insight into FDM technology, provides an idea of the process parameter settings, the available materials and ways of modifying their properties to consequently improve the quality of FDM products.

Plasma Spraying of Self-Lubricating Cr2O3-CaF2 Coatings

1997 ◽  
Author(s):  
F. Vos ◽  
L. Delaey ◽  
M. De Bonte ◽  
L. Froyen
Keyword(s):  
Plasma Spraying ◽  
Matrix Material ◽  
Production Method ◽  
Atmospheric Plasma ◽  
Spray Parameters ◽  
The Matrix ◽  
Preparation Step ◽  
Plasma Sprayed ◽  
The Relationship ◽  
Selection Of

Abstract Results are presented of a project analysing the relationship between the production parameters of plasma sprayed self-lubricating Cr2O3-CaF2 coatings and their structural, wear and lubricating properties. The production method consists of a preparation step where a powder blend of the matrix material (Cr203) and solid lubricant (CaF2) is agglomerated, followed by atmospheric plasma spraying (APS) of the agglomerates. Selection of the most appropriate agglomeration and plasma spray parameters as well as the microstructure of the coatings will be discussed.

A Process Planning Method for Improving the Build Performance in Stereolithography

1999 ◽  
Author(s):  
Aaron P. West ◽  
David W. Rosen
Keyword(s):  
Process Planning ◽  
Planning Method ◽  
Analytical Models ◽  
Multi Objective Optimization ◽  
Process Variables ◽  
Build Time ◽  
Insight Into ◽  
Conflicting Goals ◽  
Selection Of

Abstract A process planning method is presented in this paper to aid stereolithography users in the selection of appropriate values of build process variables in order to achieve specific goals and characteristics that are desirable in the end prototype. To accomplish this, user-defined input in the form of goal preferences and feature tolerances are used to control how the prototype will be built by way of process planning. The user inputs will be used to drive the creation of the process plan so that a prototype is produced, which reflects the intent of the operator. The process planning method is adapted from multi-objective optimization and utilizes empirical data, analytical models, and heuristics to quantitatively relate build process variables to goals of surface finish, accuracy, and build time. The objective is to render decision support by handling tradeoffs among conflicting goals quantitatively and give the user some degree of insight into what quality of prototype may ultimately be produced. The process planning method is demonstrated on a part with non-trivial geometric features.

Overview radiography of abdominal organs in dogs and cats

2020 ◽  
Vol 1 (4) ◽  
pp. 6-14
Author(s):  
V. N. Baymatov ◽  
◽  
A. V. Metelev ◽  
Keyword(s):  
Barium Sulfate ◽  
Bile Ducts ◽  
Individual Characteristics ◽  
Correct Selection ◽  
X Ray ◽  
Abdominal Organs ◽  
Modern Methods ◽  
Extrahepatic Bile Ducts ◽  
Selection Of

Today, less attention has been paid to x-ray studies of animals in connection with the advent of more modern methods. At the same time, the quality of radiopaque substances decreased, which is reflected in this article. The Omnipack, Urografin, Visipack, Barium sulfate, Iodipamide, Bilignost and Biligrafin used in radiopaque contrast studies in most cases did not reveal the hepatobiliary system. Only the last two drugs gave satisfactory results. The complexity of the X-ray examination of the biliary system in cats and dogs lies in the features of the location of the extrahepatic bile ducts and the condition of the intestine, the size of the liver, its structure, echogenicity, the state of the vessels and surrounding organs. In this work, we took into account the anatomical variants of the development and location of organs in animals, which may complicate the study or evaluation of the data obtained. These included changes in the contours, shape, location of the gallbladder and its filling. The results obtained were compared with the available general species standards, taking into account the possible individual characteristics of each animal. Other studied drugs gave satisfactory results with an overall assessment of the abdominal organs, but we preferred Omnipack. Survey radiography provides a large amount of information with the correct selection of radiopaque substances.

Measurement of High Thermodynamic Temperatures in the DLR Solar Furnace by UV-B Detection

Solar Energy ◽  
2002 ◽  
Author(s):  
Nicola Rohner ◽  
Andreas Neumann
Keyword(s):  
Temperature Measurement ◽  
Temperature Measurements ◽  
Solar Furnace ◽  
Correct Selection ◽  
Basic Material ◽  
Atmospheric Conditions ◽  
Spectral Measurements ◽  
System Temperature ◽  
Selection Of

The correct selection of the operating wavelength is essential for a precise pyrometric temperature measurement on solar irradiated samples, as the measurement may be disturbed by reflected solar radiation. Atmospheric conditions and particularly the emissivity as basic material property determine the amount of this reflected and the emitted radiation from a sample under investigation. An approach to solve this problem by using a monochromator system for temperature measurement in the UV-B range was developed and experimentally tested. With this system, temperature measurements were possible beginning at 1320°C and ranging up to about 2400°C. Two calculation methods are described and compared. The influence of the calibration temperature on the quality of the temperature measurement is shown. Measurements on a blackbody up to 1500°C were performed for calibration purpose. Temperature measurements on a real solar heated magnesia sample up to 2400°C are presented and discussed. These spectral measurements on hot bodies irradiated in the DLR Solar Furnace led to the final specification of the measurement wavelengths to be in the range from 280 nm to 293 nm.

The Gambler's Ruin Problem, Genetic Algorithms, and the Sizing of Populations

1999 ◽  
Vol 7 (3) ◽  
pp. 231-253 ◽  
Author(s):  
George Harik ◽  
Erick Cantú-Paz ◽  
David E. Goldberg ◽  
Brad L. Miller
Keyword(s):  
Genetic Algorithms ◽  
Building Blocks ◽  
Correct Selection ◽  
Problem Size ◽  
One Dimensional ◽  
Fitness Evaluation ◽  
Gambler’S Ruin ◽  
Gambler's Ruin Problem ◽  
Selection Of

This paper presents a model to predict the convergence quality of genetic algorithms based on the size of the population. The model is based on an analogy between selection in GAs and one-dimensional random walks. Using the solution to a classic random walk problem—the gambler's ruin—the model naturally incorporates previous knowledge about the initial supply of building blocks (BBs) and correct selection of the best BB over its competitors. The result is an equation that relates the size of the population with the desired quality of the solution, as well as the problem size and difficulty. The accuracy of the model is verified with experiments using additively decomposable functions of varying difficulty. The paper demonstrates how to adjust the model to account for noise present in the fitness evaluation and for different tournament sizes.

Synthesizing Single DOF Linkages Via Transition Linkage Identification

2007 ◽  
Vol 130 (2) ◽  
Author(s):  
Andrew P. Murray ◽  
Michael L. Turner ◽  
David T. Martin
Keyword(s):  
Classification Scheme ◽  
Degree Of Freedom ◽  
Physical Parameters ◽  
Single Degree Of Freedom ◽  
Loop Closure ◽  
Single Degree ◽  
The Matrix ◽  
Comprehensive Classification ◽  
Insight Into ◽  
Selection Of

A linkage is partially classified by identifying those links capable of unceasing and drivable rotation and those that are not. In this paper, we examine several planar single degree-of-freedom linkages to identify all changes to the physical parameters that may alter this classification. The limits on the physical parameters that result in no change in the classification are defined by transition linkages. More rigorously, a transition linkage possesses a configuration at which the matrix defined by the derivative of the loop closure equations with respect to the joint variables loses rank. Transition linkages divide the set of all linkages into different classifications. In the simplest cases studied, transition linkage identification produces a comprehensive classification scheme. In all cases, this identification is used to alter a linkage’s physical parameters without changing its classification and produces insight into the selection of these parameters to produce a desired classification.

scholarly journals Near Optimum Selection of Module Configuration for Efficient Modular Construction

2015 ◽  
pp. 95-104
Author(s):  
Osama Moselhi ◽  
Tarek Salama
Keyword(s):  
Volume Index ◽  
Construction Site ◽  
Modular Construction ◽  
Suitability Index ◽  
Optimum Selection ◽  
The Matrix ◽  
Project Construction ◽  
Cost Penalty ◽  
Selection Of

Modular construction has received considerable attention in recent years. This has been attributed to its impact on cost and time reduction and improved productivity and quality of constructed facilities. Modular construction can also result in improved safety on construction jobsites and reduced material waste. Most recent work in this field focused cranes selection and location, more suited scheduling methods and issues pertinent to logistics, without due consideration to optimized modules configuration. This paper introduces a newly developed unified modular suitability index to accomplish a near optimum selection of module configuration for efficient modular residential construction. The developed modular suitability index (MSI) utilizes five indices; 1) connections index (CI) that evaluates the module connections using the matrix clustering technique along with the bond energy algorithm, 2) transportation dimensions index (TDI) that accounts for the module dimensions’ effects on transportation, 3) transportation shipping distance index (TSDI) to evaluate the distance between modules fabrication and assembly facility and the project construction site, 4) crane cost penalty index (CCPI) to evaluate the crane cost relevant to the module placing rate, and 5) concrete volume index (CVI) to evaluate the project’s foundation concrete quantities. Calculating the modular suitability index (MSI) provides a unified indicator for the project stakeholders to assess the suitability of different modular configuration and support near optimum modules.

Procedure for Admittance of the Contractor Companies to Perform the Work at the Construction Site

2021 ◽  
pp. 24-28
Author(s):  
E.V. Glebova ◽  
◽  
E.A. Fomin ◽  
M.V. Ivanova ◽  
◽  
...  
Keyword(s):  
Injury Rate ◽  
Construction Site ◽  
Matrix Elements ◽  
Current Period ◽  
The Matrix ◽  
Industrial Injuries ◽  
High Level ◽  
The Given ◽  
Selection Of

The article is devoted to the assessment of the contractor companies activity in the field of safety both before the start of work execution and during the execution of work at the construction site of the Client’s company. Analysis is given concerning the industrial injuries from 2009 to 2018 in Russia, based on which the tendency to reduce industrial injuries for the current period is determined, and the coefficients of the frequency of injuries in various countries for 2015 are calculated. Based on the performed analysis, the injury rate in Russia is still at a high level. Economic component for the materials, personnel qualifications, and savings on safety from the Client’s company can also lead to injuries at the construction site. The main reasons for low quality of the work performed at the construction site, which in turn lead to injuries, are given in the article. Matrix for the assessment of the contractor companies was developed, with the help of which it is proposed to assess all the aspects of their activities that effect on safety of the work performed. Among the assessed aspects there are sections related to training, behavior and motivation of the personnel, audits conducted by the contractor companies in relation to the subcontractors, investigation of incidents by using the current procedures and contractor personnel responsibilities. One of the matrix elements is presented for assessment. Each element from the given section is proposed to be assessed on a scale from 0 to 3, where each aspect is presented in the form of an action, an assessment of this action and its result. Recommendations on the use of this methodology in the selection of contractors are provided.

The method of estimation of influence the type of intersection into environmental conditions

2018 ◽  
Vol 121 ◽  
pp. 351-362
Author(s):  
Aleksander Sobota
Keyword(s):  
Quality Of Service ◽  
Transport System ◽  
Environmental Conditions ◽  
Decision Problem ◽  
Road Transport ◽  
Correct Selection ◽  
Basic Assumptions ◽  
Selection Of

Functioning of transport system is determine by the quality of service realized by infrastructure of different transport branches. In case of road transport, very important are intersections. These objects are usually a bottleneck in the network. Therefore, the correct selection of the intersection type is really important in the planning and projecting process of infrastructure. So, decision problem have to be solved by the projectors, who have an influence on these process. But the selection of the intersection type is also the multi-criteria problem. Therefore the answer on the question like, does the intersection type have an influence on environmental conditions, have been presented in the article. For this purpose, the basic assumptions of the method of selections the intersection type, and results of the measurements realized at four type of intersection located on multilane arteries, have been presented in the article.

THE INFLUENCE OF ENVIRONMENTAL EFFECTS ON THE ACOUSTIC PHONON SPECTRA IN QUANTUM-DOT HETEROSTRUCTURES

2002 ◽  
Vol 12 (04) ◽  
pp. 1147-1158 ◽  
Author(s):  
SALVADOR RUFO ◽  
MITRA DUTTA ◽  
MICHAEL A. STROSCIO
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Environmental Effects ◽  
Phonon Spectrum ◽  
Acoustic Phonon ◽  
Matrix Material ◽  
Free Standing ◽  
Phonon Spectra ◽  
The Matrix ◽  
Selection Of

We present calculations of the acoustic phonon spectra for a variety of quantum dots and consider the cases where the quantum dots are both free-standing and embedded in a selection of different matrix materials — including semiconductors, plastic, and water. These results go beyond previous calculations for free-standing quantum dots and demonstrate that the matrix material can have a large effect on the acoustic phonon spectrum and consequently on a variety of phonon-assisted transitions in quantum-dot heterostructures.

Sign in / Sign up

Export Citation Format

Share Document