Wyniki wyszukiwania - BazTech

1

Surface roughness of the Ti-6Al-4V ELI titanium alloy after the turning process

Rosik R., Kępczak N., Sikora M., Witkowski B., Wójcik R., Midera S.

Archives of Materials Science and Engineering

|

2019

|

Vol. 98, nr 2

74--80

EN

Purpose: The purpose of this article is discussing the methods of determining the surface roughness of the Ti-6Al-4V ELI titanium alloy obtained after longitudinal turning. The method of determining the mathematical model used for determining the Rz roughness parameter and then the results obtained were compared with values measured and calculated on the basis of equations available in the literature. Design/methodology/approach: The mathematical model in the form of multiple regression function of exponential polynomial was determined using the algorithm of the acceptance and rejection method. The data for calculations was obtained by measuring the surface roughness after turning with different machining parameter values. Findings: A mathematical model was elaborated in the form of a multiple regression function, enabling calculation of the Rz parameter describing the Ti-6Al-4V ELI titanium alloy surface roughness after longitudinal turning. The verification of the dependence obtained confirmed its accuracy. Research limitations/implications: Further research should encompass other values of machining plate geometry, as well as other types of cooling and lubricating fluids and method of applying them. Practical implications: The mathematical model can be helpful when choosing the conditions in which the turning process will be carried out. It also constitutes a basis for further optimisation of that process. Originality/value: The results of this research are a novelty on a worldwide scale. No research of this type has been conducted with regard to analyses and optimisation of longitudinal turning of the Ti-6Al-4V ELI titanium alloy.

2

Mathematical model for determining the expenditure of cooling and lubricating fluid reaching directly the grinding zone

Stachurski W., Sawicki J., Krupanek K., Midera S.

Archives of Materials Science and Engineering

|

2018

|

Vol. 94, nr 1

27--34

EN

Purpose: The purpose of this article is to discuss the method of determining the mathematical model used for calculating the amount of emulsion reaching directly the grinding zone during the hob sharpening process. Design/methodology/approach: The mathematical model, in the form of a multiple regression function, was determined based on the acceptance and rejection method. The data for the calculations was obtained by conducting numerical simulations of fluid flow in the Ansys CFX software. Findings: A mathematical model enables calculating the amount of efficient expenditure of emulsion reaching directly the zone of contact between the grinding wheel and workpiece (hob cutter rake face) at various nozzle angle settings and different nominal expenditures of emulsion. The verification of the mathematical relationship confirmed its accuracy. Research limitations/implications: Further research should focus on the other types of grinding process and other types of cooling and lubricating fluids. Practical implications: The mathematical model enables a selection and application in the workshop and industrial practice of various variants of emulsion supply during the grinding of hob cutter rake face. Analysis of the multiple regression equation created on the basis of the acceptance and rejection method also allows predicting changes in the analyzed numerical model. Originality/value: The literature review has shown that no research of this type has been conducted with regard to analyses and optimisation of the grinding process during hob cutter sharpening. The results of this research are a novelty on a worldwide scale.

3

Calculation of volume fractions of microstructural components in steels cooled from the austenitizing temperature

Trzaska J.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 65, nr 1

38--44

EN

Purpose: The paper presents method in predicting the volume fractions of ferrite, pearlite, bainite and martensite of steel cooled continuously from the austenitizing temperature, basing on the chemical composition, austenitizing temperature and cooling rate. Design/methodology/approach: In the paper it has been applied a hybrid approach that combined application of various mathematical tools including logistic regression and multiple regression to solve selected tasks from the area of materials science. Findings: Computational methods are an alternative to experimental measurement in providing the material data required for heat treatment process simulation.Research limitations/implications: All equations are limited by range of mass concentrations of elements which is presented in Table 2. Practical implications: The worked out formulae may be used in computer systems of steels’ designing for the heat-treated machine parts. Originality/value: The paper presents the method for calculating the volume fractions of ferrite, pearlite, bainite and martensite of the structural steels, depending on their chemical composition, austenitizing temperature and cooling rate.

4

Evaluation of efficiency of working time of equipment in blast furnace department

Kardas E.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

876--880

EN

Purpose: The main aim of the paper is the evaluation of efficiency of working time of equipment in blast furnace department with the use of Overall Equipment Effectiveness (OEE) and PAMCO method. Design/methodology/approach: The investigation was made for blast furnace department in Polish steel plant. Two methods: OEE and PAMCO was used. The analysis covers the period of 7 years. The analysis was made based on different data: different types of time connected whit work of blast furnaces, interruption in blast furnace work, level of pig iron production, unit production time and quantity of non-conformance production. Findings: Performed research made it possible to determine the level of efficiency of blast furnace department. It can be concluded that working time in this department is used efficient. Factors that reduce efficiency are usually not-dependent on the company: mainly are connected with the situation on the steel market. Research limitations/implications: It is necessary to continue the research in order to assess individual blast furnaces. That analysis may enable to show if these units has the same level of efficiency and if they are affected by the same factors in the same way. Practical implications: Optimal utilization of capacity and working time of machines and equipment are important for the reduction of production costs. Use of OEE and PAMCO methods helps to assess the level of efficiency of working time and allow to find factors that has great importance for level of efficiency. Originality/value: Results of this analysis can be taken into consideration by blast furnace department under study. Analysis can help to assess the level of efficiency and find factors that influence on it.

5

Analiza właściwości zbiornikowych skał węglanowych na podstawie wyników testów RPZ i pomiarów geofizyki wiertniczej (górnojurajskie podłoże zapadliska przedkarpackiego)

Dubiel S., Zubrzycki A., Maruta M.

AGH Drilling, Oil, Gas

|

2012

|

Vol. 29, no. 1

127-134

PL

W artykule przedstawiono wyniki analizy statystycznej zależności przepuszczalności efektywnej (KDST) od porowatości Phi/geof.) w celu oceny zmian właściwości zbiornikowych górnojurajskich skał węglanowych, występujących w podłożu centralnej części zapadliska przedkarpackiego, w strefie Bochnia - Dębica - Mędrzechów. Analizę przeprowadzono wykorzystując wyselekcjonowane dane uzyskane z pomiarów geofizyki wiertniczej oraz wyników testów złożowych rurowymi próbnikami złoża (RPZ). Metodą analizy statystycznej wyznaczono odpowiednie równanie regresji w postaci: log KDST = -0,142 + 0,178 x Phi/geof. mogące być przydatne do prognozowania współczynnika przepuszczalności efektywnej na podstawie wielkości współczynnika porowatości dla węglanowych skał górnej jury podłoża zapadliska przedkarpackiego.

EN

In the paper reservoir properties - effective permeability (K/DST) and porosity Phi/geof.) of the Upper Jurassic carbonate reservoir rocks were analyzed. Data of the permeability from DST and porosity from well logging were used to determine the relationship between them by statistic methods. On the basis of analysis's results the equation as log K/DST = -0.142 + 0.178 x Phi/geof. was established for oil and gas bearing Upper Jurassic carbonate formation in central part of the Carpathian Foredeep basement (in the area: Bochnia - Dębica - Mędrzechów).

6

Klasyfikacja przypadków medycznych metodą statystyczną

Wajs W.

Automatyka / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

|

2010

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T. 14, z. 2

211-223

PL

W pracy przedstawiono problem klasyfikacji danych metodami statystycznymi. Opisana metoda klasyfikacji umożliwia obliczenie prawdopodobieństwa wystąpienia schorzenia. Przypadek chorobowy opisany jest dwoma parametrami wyrażonymi liczbami rzeczywistymi. Przypadek chorobowy może przynależeć do znanego zbioru przypadków, u których wystąpiło schorzenie, albo do zbioru przypadków w których to schorzenie nie wystąpiło. W pracy przedstawiono metodę, która umożliwia obliczenie prawdopodobieństwa, z jakim rozpatrywany przypadek chorobowy należy do zbioru etykietowanego "1" lub do zbioru etykietowanego "0". Dane źródłowe użyte w pracy są oryginalne i pochodzą z medycznej bazy danych. Algorytm metody został sprawdzony na przypadkach zebranych w praktyce klinicznej. W pracy zastosowano metodę korelacji w celu otrzymania odpowiednich statystyk. Obliczony współczynnik korelacji na poziomie 0,8 wskazuje na wystąpienie schorzenia. Równocześnie współczynnik korelacji na poziomie 0,0 wskazuje na brak wystąpienia schorzenia. Własność ta jest wykorzystywana w algorytmie klasyfikacji. W praktyce klinicznej często występuje sytuacja, gdy mamy jeden przypadek testowy i chcielibyśmy określić, czy ten przypadek opisuje symptomy wskazujące na szansę wystąpienia określonego schorzenia. Zagadnienie klasyfikacji to problem wystąpienia schorzenia bpd, który rozważa się w okresie poprzedzającym wystąpienie choroby na 3 do 4 tygodni wcześniej. Bronchopulmonary dysplasia (bpd) jest chronicznym schorzeniem płuc, które rozwija się u noworodków dla których zastosowano wentylację mechaniczną. Większość przypadków wystąpienia bpd dotyczy noworodków urodzonych przedwcześnie, przed 34 tygodniem ciąży i z wagą urodzeniową mniejszą niż 1500 g. Te dzieci są częściej narażone na stan znany w literaturze jako Respiratory Distress Syndrome (RDS). RDS jest rezultatem uszkodzenia delikatnej tkanki płuc podlegającej mechanicznej wentylacji w dłuższym czasie. Wentylacja mechaniczna w wielu przypadkach warunkuje przeżycie noworodka. Ważnymi czynnikami wystąpienia bpd są przedwczesne urodzenie, infekcje, wentylacja mechaniczna oraz tlenozależność.

EN

The problem of data classification with statistical methods is presented in the paper. Described classification method enables calculation of probability of disease incidence. A case of disease incidence is described with two parameters expressed in real numbers. The case can belong to a known set of cases there the disease occurred or to the set where the disease did not occur. There was presented a method for calculating probability with which a given case belongs to the set labeled as "1" or "0". Source data used in the paper come from medical databases and are original. The algorithm of the method was checked on clinical cases. Correlation method was used for generating respective statistics. The calculated correlation at a level of 0.8 is indicative of disease occurrence, whereas the correlation coefficient at a level of 0.0 is indicative of lack of disease. This property is used in the classification algorithm. It is frequent in the clinical practice that we have one test case and we try to determine whether or not that case describes symptoms of liability to the disease. Classification is related with the occurrence of disease bpd, which is analyzed in a 3 to 4 week period preceding the disease incidence. Bronchopulmonary dysplasia is a chronic lung disease that develops in neonates treated with oxygen and positive pressure ventilation. The majority of bpd cases occur in premature infants, usually those who have gestational ege less than wp = 34 weeks and birth weight less than mu = 1500 g. These babies are more likely to be affected by a condition known as infant Respiratory Distress Syndrome, which occurs as a result of tissue damage to the lungs from being mechanical ventilator for a significant amount of time. Although mechanical ventilation is essential to their survival over time the pressure from the ventilation and excess oxygen intake can injure a newborn's delicate lungs. If symptoms of respiratory distress syndrome persist then the condition is considered Broncho-pulmonary Dysplasia. Important factors in diagnosing bpd are prematurely, infection, mechanical ventilator dependence, and oxygen exposure.

7

Ocena funkcjonowania oczyszczalni ścieków metodami statystycznymi

Wałęga A.

Forum Eksploatatora

|

2009

|

Nr 5 (44)

30-34

PL

Zagadnienia związane z awaryjnością czy ryzykiem w zakresie inżynierii sanitarnej odnoszą się głównie do problemów zaopatrzenia i dystrybucji wody. W przypadku systemów oczyszczania ścieków ciągle brak jest powszechnego wykorzystania metod statystycznych do oceny eksploatacyjnej oczyszczalni ścieków. Powszechnie ocenę funkcjonowania oczyszczalni ścieków dokonuje się poprzez porównanie wartości wskaźników zanieczyszczeń w ściekach oczyszczonych, często wyrażonych jako średnia arytmetyczna, do dopuszczalnych podanych w obowiązujących aktach prawnych lub na obliczeniu procentowej redukcji zanieczyszczeń na ciągu technologicznym oczyszczalni. Jest to podejście uproszczone, w którym nie dostaniemy informacji na temat m.in. czasu trwania awarii (w tym przypadku rozumianej jako czas trwania przekroczenia przez dany wskaźnik wartości dopuszczalnej), stabilności procesu oczyszczania ścieków i czynników zakłócających ten przebieg, czy prognozy efektywności pracy systemu oczyszczania ścieków.

8

The propagation of variability of polymer processing parameters in production lines

Bociąga E., Pietrzak M., Postawa P.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

|

Vol. 26, nr 1

26-32

EN

Purpose: Analysis the propagation of the variability of polymer processing in production lines is the aim of the article. It is unprofitable occurrence. It contributes to an increase in the time of the production cycle and the volume of work in process. Design/methodology/approach: For the measurement of the variability of polymer processingparameters the time Shewart's card were used. The technique of the timing was applied for the registration of the production cycle time and the volume of stocks. The computer simulation was used for the analysis of the propagation of the variability in the production line at different values of the variability coefficient. Findings: The Shewart’s card permit to control the random variability of processes and eliminate the negative results of this occurrence. The computer simulation allowed to the investigate a lot of screenplays assuming different sizes of the variability. Prediction of the variability of polymer processing parameters gives possibility for the correction of the manufacturing process organization and against wastage. Research limitations/implications: The next step of research will be. Determinations of relation between the variability of polymer processing parameters and coefficient of machines utilization and quality of the final product will be the next stage of the research. The validation simulation models and estimation of their usefulness in undertaking of the decision concerning production process. Practical implications: The analysis of the propagation of variability of polymers processing parameters permits for better are understanding of reasons delays and excessive work in progress materials in the production of a particular article. The inspection of the variability permits better to manage the materials flow in the production system.

9

The curvilinear coordinates' approach to the smart-designs generation problem

Pietraszek J.

Archives of Materials Science and Engineering

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2008

|

Vol. 34, nr 1

48-51

EN

Purpose: The aim of this paper is to present an alternative approach to the problem of accuracy estimation for smart-designs' class (also named space-filling or intelligent design) by making use of the design’s geometrical properties. Design/methodology/approach: The assumed topographical condition: ‘all design cases have to be on the defined surface' is reversed into a curvilinear coordinate system mapped on this surface. Then a sequence of irregular experimental designs is generated on the surface with various descriptive parameters and sampling from testing function is taken. Next, the identification of a general linear-quadratic model is conducted and various accuracy measures in comparison to a test function are calculated. At last the monotonic correlation analysis between accuracy measures and the design's geometrical properties is conducted. Findings: Significant and strong correlation between the accuracy measures and some of the geometrical properties has been found. Research limitations/implications: The correlations found are a strong suggestion for further research. The future investigations should be provided with various and more complicated testing functions and different topographical conditions. The relations between geometrical properties and accuracy measures need to be identified and their distributions and confidence intervals need to be determined. Practical implications: The results obtained outline the method of the approximation accuracy estimation from geometrical properties of the design. Originality/value: Worked out formulas may be of a significant value for those conducting data mining in technological data warehouses.

10

Radial basis function simulation and metamodelling of surface roughness in centreless grinding

Krajnik P., Sluga A., Kopac J.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 14, nr 1-2

104--110

EN

Purpose: The purpose of this study was to investigate the efficiency of artificial neural networks and the related metamodels to simulate and identify complex centreless grinding process. Design/methodology/approach: The modeling is founded on the system approach, which is efficiently dealing with the complexity of the grinding process. The unknown process transfer function is identified via artificial neural network that requires fewer assumptions and less precise information about the process modeled than other conventional modeling techniques. The developed metamodel is a response surface (polynomialfit) of the simulated process that is achieved by the computer model. Findings: The metamodel quality is strongly related to the prediction accuracy of the underlying simulation model. The generalization capability of an artificial neural network is sensitive to the training samples (design of experiments). The predictive ability of a metamodel is comparable to the accuracy of the response surface regression model. Research limitations/implications: Improved simulation model and application of unconventional metamodels (Gaussian process regression) will significantly improve the presented preliminary results. Originality/value: Metamodelling of computer experiments is an expansion of response surface methodology and the classical designs of experiments and represents a new paradigm in empirical modelling of machining operations.

11

Prognosing the durability of polymer sealings

Okularczyk W., Kwiatkowski D.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 17, nr 1-2

125--128

EN

Purpose: The paper describes the phenomena connected with the sealing for water hydraulic systems. Design/methodology/approach: For the durability tests two types of sealings, made of three polymeric materials recommended for use in water hydraulics systems have been used. In all investigation arrangements the same guide elements have been used. The tests have been performed maintaining water pressure on the sealing at a level of p = 8±1 MPa and the average speed of the piston rod of v ≈ 0.35 m/sec. Water temperature during investigations was regulated within the range of Tmin = 291 K and Tmax = 305 K. The leakage was distributed to the measurement hoses with the internal diameter of 5mm. For the investigations, the working piston rod with ø 45 f7 with the following parameters has been used: Material: chromium-nickel steel AISI 431 (Cr=16.7%, Ni=2.08%) covered with hard chromium plating of ≥ 20 μm, micro-cracks number ≤ 5 000/mm2, Ra = 0.07 μm. Findings: Weibull method, thanks to its multifunctionality, helps to select elements for certain applications (required long failure-free mileages → high characteristic durability – sealings series 30413). Equipment which works sporadically → low characteristic durability but e.g. lower weight and sizes of sealing element – sealing series 30412. Practical implications: Within the confines of the given research concerning an optimal choice of piston rod sealing for water hydraulic systems, large dependence of the sealing durability on the properly chosen guide elements of the piston rod has been found. In extreme cases the durability changed even a few times. Originality/value: The Weibull method has been applied for assessment of durability and reliability of mechanical parts. A computer program has been used to compare two types of piston rod seals used in water hydraulic power systems. Durability limits have been estimated even though discontinued measurement data were used.

12

Prediction of in-flight particle behaviors in plasma spraying

Fang J. C., Zeng H. P., Xu W. J., Zhao Z. Y., Wang L.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 18, nr 1-2

283--286

EN

Purpose: In plasma spraying, the coating properties such as porosity, hardness, strength, etc. are directly determined by particle behaviors, i.e. the temperature and velocity. Therefore, it is necessary and meaningful to predict the particle behaviors under a certain combination of process parameters before the spraying process is executed. Design/methodology/approach: In this study, SVM (Support Vector Machines) is applied to the prediction of in-flight particle temperature and velocity in plasma spraying by argon flow rate, hydrogen flow rate and electric current. The influences of the three parameters on particle temperature and velocity are also investigated. Findings: In the leave-one-out cross validation on an orthogonal experiment with 9 sets of parameters, the maximum relative errors of prediction for particle temperature and velocity are 0.68% and 1.42% respectively. The prediction results reveal that the most influential parameter for particle temperature is hydrogen flow rate, and argon flow rate exerts the greatest influences on particle velocity. Research limitations/implications: Future work should focus on the modeling of the whole spraying proces with all the spraying parameters. Practical implications: It will be helpful to the prediction and controll of particle behaviors in plasma spraying. Originality/value: First application of SVM to modeling the in-flight particle behaviors in plasma spraying.

13

Influence of variability of polymer processing on the manufacturing system

Koszkul J., Pietrzak M., Gzieło A., Postawa P.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 17, nr 1-2

253--256

EN

Purpose: The aim of the paper is to present the influence of variability of polymer materials processing parameters on the production process. To determine this influence, the queuing theory and system dynamics method have been applied. Design/methodology/approach: The measurements and control of the time of operation can be performed by means of the traditional methods of statistical control. Full dynamics of the variability phenomenon can be reflected by means of computer simulation. Findings: The measurements of parameters on the basis of real manufacturing system have been performed. The dependences between the parameters have been determined and several computer simulations have been performed. On the basis of the obtained results the influence of the individual production parameters on the manufacturing system has been determined. Research limitations/implications: The performed analysis enabled to assume that the highest influence on the manufacturing process and especially on the time of material flow has the time of injection of the polymeric materials. Reductions in utilization tend to have a much larger impact on delay then reduction in variability. However, because capacity is costly, high utilization is usually desirable. Originality/value: The investigation results can be the basis to develop efficient methods for reduction of variability and hence the methods of production costs reduction. Variability reduction is often the key to achieving high efficiency logistical and manufacturing system.

14

Influence of injection moulding parameters on resistance for cracking on example of PP

Kwiatkowski D., Nabiałek J., Postawa P.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 17, nr 1-2

97--100

EN

Purpose: Purpose of this paper is analysis of injection moulding conditions influence on fracture mechanics on example of PP. Design/methodology/approach: For the cracking tests, polypropylene with the commercial name Reslen manufactured by Polimarky has been used. Samples for the tests have been made by injection method on injection machine Krauss-Maffei with symbol KM65 – 160. The machine was equipped with high class control system with symbol C4. Variability of the four following parameters of injection process was taken into consideration: injection temperature, temperature of mould, pressure of closing and injection speed. It also should be reminded about analysis of correlation multidimensional, analysis Pareto enabling evaluation of weight of following entrance values in model comparing (regression), what is the base of optimal actions. Crack resistance examination were carried out using a special device allowing measurements of basic parameters of crack mechanics, such as: coefficients of stress intensity, gap divergence and J integral. Findings: On value of the integrity J being measure of crack resistance the biggest influence have the mould temperature and injection temperature. Research limitations/implications: Analysis of influence the values of following injection parameters for changing the crack resistance during dynamic bending for PP has been done in the future. Practical implications: The results of experiments will allow to determine the recommendations referring to the optimization of processing conditions, and as a result of this polymer will have high fracture resistance. Originality/value: The samples for the test have been prepared on base of elaborated schedule. It has been prepared with help of specialist modulus DoE Design of Experiment from packet STATISTICA 6.0 PL.

15

Comparison of rollers after sowing of buckwheat

Mursec B., Janzekovic M., Cus F., Zuperl U.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 17, nr 1-2

269--272

EN

Purpose: This paper compares the effect of three types of rollers (rubber, edged and smooth) upon sprouting of three sorts of buckwheat seed (‘Darja’, ‘Bamby’ and ‘Gorenjka’). Rolling is a very important soil cultivation measure after sowing of small seed such as the buckwheat seed, particularly, during the time of drought when the test was performed. Design/methodology/approach: A field test was carried out on divided lots of land in a random block. Sowing and rolling were performed on 6 June 2003. During that period there was an extreme drought causing lack of humidity in the ground. The plants were counted on the 10 and 12 July, i.e., on the fourth and sixth day after sowing. There were most sprouting plants in case of rubber rollers, followed by smooth and edged rollers. Findings: The least plants sprouted on the non-rolled lots of land. The sort had a statistically characteristic effect on the share of plants sprouting during the fourth and sixth day after sowing. Research limitations/implications: The research was carried out only with three types of rollers and three sorts of buckwheat seed. Practical implications: The sort ‘Gorenjka’ had most sprouting plants, followed by the sort ‘Bamby’ and the sort ‘Darja’ with least sprouting plants. Originality/value: In our researches it was proved that the most favourable combination is the rubber roller and the sort ‘Gorenjka’.

16

Pomiar opóźnienia przy zastosowaniu charakterystyki fazowej wzajemnej gęstości widmowej mocy

Hanus R.

Zeszyty Naukowe Politechniki Rzeszowskiej. Elektrotechnika

|

2002

|

z. 22 [192]

93-98

PL

W artykule przedstawiono zasadę pomiaru opóźnienia przy wykorzystaniu charakterystyki fazowej wzajemnej jednostronnej gęstości widmowej mocy. Omówiono niektóre właściwości metody i przeanalizowano błędy statystyczne estymacji opóźnienia.

EN

In this article the statistic method of time delay measurement by use phase of cross-spectral density function are presented. The statistical errors of time delay estimation are analysed.