Wyniki wyszukiwania - BazTech

1

Application of solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) and comparison of both detection techniques (DAD and FLD) to analyse nesfatin-1 in fetal bovine serum samples

Tuzimski Tomasz, Szubartowski Michał

Acta Chromatographica

|

2023

|

Vol. 35, no. 3

286--292

EN

In this study, we propose a simple, cost-effective, and sensitive high-performance liquid chromatography with both detection techniques such as diode-array detection and fluorescence detection (HPLC-DAD-FLD) for the determination of nesfatin-1 in fetal bovine serum samples. The limit of detection (LOD) and limit of quantification (LOQ) for nesfatin-1 were set at satisfactory values in the range 0.22–0.35 mg mL⁻¹ and in the range 0.67–1.05 mg mL⁻¹, respectively (at two different wavelengths (DAD) and at four different wavelengths (FLD)). Analyte concentrations were determined as the average value from fetal bovine serum matrix samples. The preliminary results show that the SPE procedure on Isolute Si-TsOH (SCX-3) could be used for further nesfatin-1 analyses in human serum samples. Both the SPE technique, chromatographic analysis with gradient elution mode and detection technique are fast and convenient.

2

Studies on influence of torch orientation on microstructure, mechanical properties and formability of AA5052 CMT welded blanks

Girinath B., Siva Shanmugam N., Sathiyanarayanan C.

Archives of Civil and Mechanical Engineering

|

2020

|

Vol. 20, no. 1

197--218

EN

Generally, in gas metal arc welding (GMAW) high heat input causes drastic changes in the microstructures of weldment (fusion zone and heat affected zone), which in turns affects the performance of the welded blanks during forming operation. The present study focuses on the parametric effects such as welding current, welding speed and torch orientation concerning welding direction on mechanical properties, microstructural characterization and formability of AA5052 Cold metal transfer (CMT) welded blanks (WB’s). Based on the macrostructure images obtained from various trials (trial 19, 20 and 21, which is corresponding to Drag angle of 10°, 90° or Zero angle and Push angle of 10°, respectively) three were selected for further studies. The macrograph, microstructural evaluation, mechanical behavior and forming limit curve (FLC) of the WB’s are examined for the selected parameters and for base metal (BM). The formability of the BM and WB’s are investigated by obtaining FLC using Nakajima test. Of the three different torch orientation concerning welding direction, the WB made with 10° push angle yields the superior mechanical properties such as high tensile strength, increase in hardness and more bending strength than the remaining torch orientations. In addition, total elongation and formability are of concern; drag angle of 10° yields the better result, compared to the other torch orientations.

3

Forming Limit Diagram, Void Analysis, Strain Distribution and Surface Roughness for SS430 Sheets During Multipoint Incremental Forming

Ramkumar K., Paulraj G., Elangovan K., Sathiya Narayanan C.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 4

1709--1714

EN

Single point incremental forming process is a most economical Die-less forming process. The major constraint of it is that it is a time consuming process. In this work, a new attempt was made in incremental forming process using Multipoint tool for SS430 sheets to increase the formability and to reduce forming time. Fractography analysis was made to study the size of voids that were formed during fracture. The forming limit diagrams were drawn and compared for single point incremental forming and the multipoint incremental forming of SS430 sheet. It was proved that the formability of SS430 sheet in the multipoint forming was better than the formability of that in single point forming and the time consumed was reduced. The strain distribution in both processes had also been studied along with surface roughness.

4

Porównanie metod wyznaczania KOG w teście Nakazimy i Marciniaka

Polak S., Niechajowicz A.

Hutnik, Wiadomości Hutnicze

|

2014

|

Vol. 81, nr 8

577--580

PL

W pracy przedstawiono porównanie wyników badań tłoczności blach metodami Nakazima i Marciniaka. Na płaszczyźnie odkształceń głównych wyznaczono krzywe odkształceń granicznych. Zaobserwowano znaczące różnice w wartościach krytycznych odkształceń pomiędzy zastosowanymi metodami. W celu wyjaśnienia różnic wykonano symulacje numeryczne prób tłoczności. Porównano przebiegi narastania odkształceń głównych w trakcie wykonywania prób.Analiza wyników wykazała istotne różnice. W teście Nakazima historia odkształceń jest nieliniowa i w trakcie tłoczenia następuje zmiana stanu odkształcenia, co może mieć wpływ na wartość graniczną odkształceń głównych. W związku z tym porównano zewnętrzne i wewnętrzne odkształcenia blachy w próbach tłoczności metodą Nakazimy.

EN

The paper presents the comparison of test results of sheets’ drawability by Nakazima and Marciniak methods. On the plane of principal strain the forming limit diagram was determined. There was observed a significant difference in the values of the critical strain between used methods. In order to explain the differences, numerical simulations of drawability were performed. The rises in the courses of principal strain during the tests were compared. Analysis of the results showed significant differences. In Nakazima test the history of strain is non-linear and during pressing a change in the state of strain occurs, which can affect the value of the limit of principal strain. Therefore, the external and internal strain of sheet metal was compared for the drawability test by Nakazima.

5

General overview of sheet incremental forming

Tisza M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2012

|

Vol. 55, nr 1

113--120

EN

Purpose: The aim of this research paper is to give a general overview on sheet incremental forming as an emerging field in small and batch production. Design/methodology/approach: First the historical and literature background of sheet incremental forming will be given, and then some theoretical and practical issues of the incremental forming processes will be described including the research work done by the author at the University of Miskolc. This research is part of an international EUREKA project with the main focus on formability and accuracy in incremental sheet forming. Findings: In this research paper some important findings on the critical wall angle which is a characteristic formability feature in incremental sheet forming will be discussed. New specimen geometry was elaborated to reduce the great amount of experimental work to determine the formability limits. The main conclusions are that in incremental forming the formability is significantly higher compared to conventional sheet forming. The process is very flexible and economic due to the low tool costs. Research limitations/implications: One of the main target areas of further research work is the determination of technological window for sheet incremental forming of various materials and to introduce this novel process into industrial practice. Practical implications: In practical applications besides the economy of the process due to its very low tool expenses, the flexibility should be mentioned which is very important in small batch production and particularly in rapid prototyping. Originality/value: The results achieved within this research work are equally important both from the point of view of theoretical and practical aspects of sheet incremental forming.

6

Zastosowanie metody cząsteczkowych najmniejszych kwadratów (PLS) do klasyfikacji danych mikromacierzowych

Błaszczyk P., Stąpor K.

Studia Informatica

|

2007

|

Vol. 28, nr 2

31-45

PL

W artykule przedstawiono wprowadzenie metody cząsteczkowych najmniejszych kwadratów (PLS) i jej zastosowanie w klasyfikacji danych mikromacierzowych. W tym celu porówanano ze sobą dwie metody klasyfikacji - liniową dyskryminację Fishera (FLD) oraz metodę cząsteczkowych najmniejszych kwadratów (PLS). Jako dane mikromacierzowe wykorzystano symulowane zbiory danych oraz dane biologiczne.

EN

In this paper we present methematical introduction of Partial Least Squares metod (PSL) and application for classification microarray data. To do this application two classification methods was compared - Fisher linear discriminant (FLD) and partial Least Squares (PLS) applied to classification of microarray data are compared. The simulation and biological datasets are used as a microarray gene expresion data.