Optimization of the installation sequence for the temporary fasteners in the aircraft industry

2021 ◽  
pp. 1-25
Author(s):  
Tatiana Pogarskaia ◽  
Sergey Lupuleac ◽  
Julia Shinder ◽  
Philipp Westphal
Keyword(s):  
Combinatorial Problem ◽  
Hole Drilling ◽  
Assembly Process ◽  
Process Verification ◽  
Final Assembly ◽  
Uncertain Input ◽  
Uncertain Input Data ◽  
Aircraft Production

Abstract Riveting and bolting are common assembly methods in aircraft production. The fasteners are installed immediately after hole drilling and fix the relative tangential displacements of the parts, that took place. A proper fastener sequence installation is very important because a wrong one can lead to a “bubble-effect”, when gap between parts after fastening becomes larger in some areas rather than being reduced. This circumstance affects the quality of the final assembly. For that reason, the efficient methods for determination of fastening sequence taking into account the specifics of the assembly process are needed. The problem is complicated by several aspects. First of all, it is a combinatorial problem with uncertain input data. Secondly, the assembly quality evaluation demands the time-consuming computations of the stress-strain state of the fastened parts caused by sequential installation of fasteners. Most commonly used strategies (heuristic methods, approximation algorithms) require a large number of computational iterations what dramatically complicates the problem. The paper presents the efficient methods of fastener sequence optimization based on greedy strategy and the specifics of the assembly process. Verification of the results by comparison to commonly used installation strategies shows its quality excellence.

scholarly journals Inverse Identification of Elastic Properties of Constituents of Discontinuously Reinforced Composites

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2332 ◽  
Author(s):  
Witold Ogierman
Keyword(s):  
Composite Materials ◽  
Elastic Properties ◽  
Micromechanical Model ◽  
Reinforced Composites ◽  
Inverse Identification ◽  
Identification Procedure ◽  
Uncertain Input ◽  
Uncertain Input Data ◽  
Selection Of

This paper is devoted to determination of elastic properties of composite constituents by using an inverse identification procedure. The aim of the developed identification procedure is to compute the elastic constants of individual material phases on the basis of known properties of composite materials. The inverse problem of identification has been solved by combining an evolutionary algorithm with a micromechanical model. The paper also focuses on selection of a suitable micromechanical model for optimization which should ensure a compromise between accuracy and complexity. Two different cases have been studied: composite reinforced with short cylindrical fibers and composite reinforced with cubic particles. Moreover, Monte Carlo simulations have been carried out to expose a difference in outcome of identification which may occur when uncertain input data is considered. Obtained results show that identification is successful only when properties of composite materials with at least two different volume fractions of the reinforcement are known.

Tingkat Pemahaman Kompetensi Guru Pada Mahasiswa Pendidikan Geografi Sebagai Calon Guru Geografi

2020 ◽  
Vol 21 (1) ◽  
pp. 102-117
Author(s):  
Novia Zalmita ◽  
Muhajirah Muhajirah ◽  
Abdul Wahab Abdi
Keyword(s):  
Prospective Teachers ◽  
Prospective Teacher ◽  
Quantitative Description ◽  
Population Data ◽  
Geography Education ◽  
Teacher Competence ◽  
Education Department ◽  
Long Time

One that influences human resource indicators is education. The teacher is a profession as a job of academic specialization in a relatively long time in college. Understanding related to teacher competence is very important to have by a prospective teacher because it can affect the quality of performance as a professional teacher. The teacher's competence is known as pedagogic, professional, social and personality competencies. The issue in this study is how the competency of the teacher of the Department of Geography Education FKIP Unsyiah as a prospective teacher of geography? The purpose of this study was to determine the competence of teachers in the Department of Geography Education FKIP Unsyiah as prospective geography teachers. Quantitative description approach is used in this study to find answers to the issue. The population in this study were students of the Department of Geography Education FKIP Unsyiah class of 2015 and 2016 who had been declared to have passed the Micro Teaching and Magang Kependidikan 3 course totaling 50 people. Because the population is small and can be reached, the determination of the sample using total sampling techniques so that the sample in this study is the whole population. Data collection is done by distributing test questions to respondents. The data was analyzed using the descriptive statistics percentage formula. The results of the study indicate that the level of teacher competence of Geography Education Department students as prospective teachers is in the moderate category, namely as many as 22 respondents (44%). A total of 12 respondents (24%) were in the high category, 15 respondents (30%) were in the low category and 1 respondent (2%) were in the very low category.

Fluctuations of Annual Precipitation and Water Resources Quality in Ukraine

2016 ◽  
Vol 10 (4s) ◽  
pp. 621-629
Author(s):  
Valentina Pidlisnyuk ◽  
◽  
John Harrington JR ◽  
Yulia Melnyk ◽  
Yuliya Vystavna ◽  
...  
Keyword(s):  
Water Resources ◽  
Surface Waters ◽  
Precipitation Amount ◽  
Ion Concentration ◽  
Annual Precipitation ◽  
Resource Quality ◽  
Phosphate Ion ◽  
Regional Trends

The article focuses on examining the influence of fluctuations in annual precipitation amount on the quality of surface waters. Water quality was estimated with data on BOD, COD and phosphate–ion concentration within five selected regions of Ukraine. Analysis of the precipitation data (1991 – 2010) showed different regional trends. Using the statistics, determination of the interconnection between precipitation amount and water resources quality were done. The obtained regularities and associated uncertainties can be used for prediction of changes in water resource quality and as a guide for future adaptation to possible climate change.

POTENSI PENGEMBANGAN SADE SEBAGAI DESA WISATA LOMBOK

2016 ◽  
Vol 20 (2) ◽  
pp. 69-82
Author(s):  
W. Suprihatin ◽  
H. Hailuddin
Keyword(s):  
Analytical Hierarchy Process ◽  
Environmental Aspect ◽  
Priority Level ◽  
Highest Weight ◽  
Local Tradition ◽  
Tourist Village ◽  
Hierarchy Process ◽  
Initial Pattern

The background of the problems in this study is the decreasing quality of Sade hamlet amid rising tourist arrivals. From the environmental aspect, the conditions of the hamlet began to decline, in which the initial pattern of Sade has started a lot of changes towards the deficient and began to leave the local tradition. One effort to improve the condition of Sade hamlet in social, cultural and the environmental aspect is through the formulation of a sustainable structuring, the presence and identity maintaining and making a sustainable Tourism Village. Through analysis of AHP (Analytical Hierarchy Process) by collecting the perceptions of some experts through interviews and questionnaires, obtained by weighting the priority of the experts, namely the preservation of culture as an element of priority-level goals to be achieved in the development of Sade Hamlet as a tourist village at 0,476. While the determination of the level of the main criteria in the achievement of these objectives is the highest weight while maintaining a typical village environment at 0.319. Priority strategies that get the highest weight of the experts is that Sade Hamlet Revitalization with a priority weighting of 0.583. The second priority is the relocation of Hamlet at 0.235. Lowest weighting or last priority is Replication Sade Hamlet at 0.182.

Automation of selected brazes' dynamic properties in high-temperatures' measurement process

2013 ◽  
Vol 18 (2-3) ◽  
pp. 33-41
Author(s):  
Dominik Sankowski ◽  
Marcin Bakala ◽  
Rafał Wojciechowski
Keyword(s):  
Surface Tension ◽  
High Temperatures ◽  
Dynamic Properties ◽  
Automatic Measurement ◽  
Measurement Methodology ◽  
Joining Process ◽  
Wetting Force ◽  
Research Grant

Abstract The good quality of several manufactured components frequently depends on solidliquid interactions existing during processing. Nowadays, the research in material engineering focuses also on modern, automatic measurement methods of joining process properties, i.a. wetting force and surface tension, which allows for quantitative determination of above mentioned parameters. In the paper, the brazes’ dynamic properties in high-temperatures’ measurement methodology and the stand for automatic determination of braze’s properties, constructed and implmented within the research grant nr KBN N N519 441 839 - An integrated platform for automatic measurement of wettability and surface tension of solders at high temperatures, are widely described

X-ray fluorescence determination of zinc sulfate in acidic zinc plating electrolyte

2020 ◽  
Vol 86 (10) ◽  
pp. 18-22
Author(s):  
K. N. Vdovin ◽  
K. G. Pivovarova ◽  
N. A. Feoktistov ◽  
T. B. Ponamareva
Keyword(s):  
Zinc Sulfate ◽  
Zinc Coating ◽  
Electrolyte Composition ◽  
Complexometric Titration ◽  
X Ray ◽  
Fluorescence Determination ◽  
Zinc Plating ◽  
Zinc Determination

Zinc sulfate is the main component in the composition of the acidic zinc plating electrolyte. Deviation in the electrolyte composition from the optimum content leads to destabilization of the electrolysis process and deteriorate the quality of the resulting zinc coating. The proper quality of a zinc coating obtained by galvanic deposition can be ensured only with timely monitoring and adjustment of the electrolyte composition. A technique of X-ray fluorescence determination of zinc (in terms of zinc sulfate) in an acidic zinc plating electrolyte is proposed. The study was carried out using an ARL Quant’X energy dispersive spectrometer (Thermo Fisher Scientific, USA) with a semiconductor silicon-lithium detector. The features of the spectrometer design are presented. The optimal parameters of excitation and detection of zinc radiation were specified when the electrolyte sample was diluted 1:1000. The ZnKα1 line was used as an analytical line. The plotted calibration graph is linear, the correlation coefficient being 0.999234. The results of zinc determination according to the developed method were compared with the data of the reference method of complexometric titration to prove the reliability of the procedure. The results are characterized by good convergence and accuracy. The proposed method of X-ray fluorescence zinc determination in a zinc plating electrolyte equals complexometric titration in the limiting capabilities and even exceeds the latter in terms of the simplicity of sample preparation and rapidity. The developed method of X-ray fluorescence determination of zinc is implemented in analysis of the electrolyte used in the continuous galvanizing unit at «METSERVIS LLC».

INFLUENCE OF DICARBOXYLIC ACIDS ON SOWING QUALITY OF SPRING BARLEY

1970 ◽  
pp. 22-25
Author(s):  
N. N. Loy ◽  
S. N. Gulina
Keyword(s):  
Organic Acids ◽  
Spring Barley ◽  
Dose Range ◽  
Dicarboxylic Acids ◽  
Rotary Machine ◽  
Working Solution ◽  
Negative Effect ◽  
Sprouted Seeds

The effect of presowing seed treatment on various concentrations of dicarboxylic (organic) acids on the sowing characteristics of spring barley has been studied. Seeds were treated with organic acids obtained by exposing cuttings to the radiation with a dose of 100 kGy and consequent hydrolysis, in concentrations: 1•10-7 %; 1•10-9; 1•10-11; 1•10-13 and 1•10-15 % on a laboratory rotary machine RVO-64 for one day before laying for germination. Distilled water was used for the control case. The rate of application of the working solution calculated as 10 liters / ton of seeds. Seeds were germinated in filter paper rolls in accordance with GOST 12038-84 requirements. The temperature was maintained at +24 ° C in the thermostat where the glasses with rolls were placed. For determination of germinative power and laboratory germination the sprouted seeds were evaluated after three and seven days, respectively. In laboratory experiments it was established that the treatment of barley seeds of varieties Zazersky 85, Nur and Vladimir with organic acids (OK) in different concentrations had both a stimulating and a negative effect. On the Zazersky 85 variety, in variants with acid concentrations of 1•10-9 and 1•10-11, an increase in germination energy (EP) by 2-4% and a significant decrease (by 3-4%) of laboratory germination (LV) of barley seeds were noted. On the Nur variety, the increase in EP was observed at 4% (concentration 1•10-11), LV and seed growth force (CPC) by 2-7% at a concentration of 1•10-7 and in the dose range 1•10-11 - 1•10-14 compared to the control values. On the grade of Vladimir, an increase in EP, LV, and CPC was found to increase by 1-6% at concentrations OK 1•10-7 and 1•10-13. It was shown that the treatment of seeds with acids led to an increase in the length of the germ in all studied varieties (by 3-9%) and dry biomass of 7-day-old seedlings - by 3-6%. Consequently, the treatment of seeds with a mixture of dicarboxylic acids has a stimulating effect on the sowing quality of spring barley.

MODIFIKASI MODEL PEMBELAJARAN TEAM ASSISTED INDIVIDUALIZATION DENGAN STRATEGI PEMBELAJARAN TUGAS DAN PAKSA

2019 ◽  
Vol 2 ◽  
Author(s):  
Lea Christy Restu Kinasih ◽  
Dewi Fatimah ◽  
Veranica Julianti
Keyword(s):  
Cooperative Learning ◽  
Learning Strategies ◽  
Learning Process ◽  
Learning Model ◽  
Learning Models ◽  
Classroom Learning ◽  
Quality Of Learning ◽  
The Given

The selection and determination of appropriate learning strategies can improve the results to be obtained from the application of classroom learning models. This writing aims to discipline students to develop individual abilities of students to be more active in the learning process and improve the quality of learning. The learning process in Indonesia in general only uses conventional learning models that make students passive and undeveloped. In order for the quality of learning to increase, the Team Assisted Individualization learning model is combined with the task learning and forced strategies. The Team Assisted Individualization cooperative learning model is one of the cooperative learning models that combines learning individually and in groups. Meanwhile, task and forced learning strategies are strategies that focus on giving assignments that require students to complete them on time so that the learning process can run effectively. Students are required to do assignments according to the given deadline. This makes students become familiar with the tasks given by the teacher. Combining or modifying the learning model of the assisted individualization team with forced and forced learning strategies is expected to be able to make students more active, disciplined, independent, creative in learning and responsible for the tasks assigned. Therefore this method of incorporation is very necessary in the learning process and can be applied to improve the quality of learning in schools.

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