Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 4
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

Previous research reported about high comorbidity between asthma and neurodevelopmental disorders. Recently, asthma was associated also with executive functions poorness. The current study aimed to investigate the verbal and visual memory performances among fifteen asthmatic kindergarten children compared to the performances of other fifteen healthy kindergarten children. The results showed that the asthmatic group revealed poor performances in the immediate short term verbal memory and the verbal working memory tests but not in the verbal learning test as it was compared to the healthy group. In addition, the asthmatic group revealed poor performances in the visual memory tasks compared to the healthy group. The results were explained in light of the assumption that poor executive functions might be interfere the process of managing the attentional resources which are needed through the process of memory encoding and retrieval.

Go to article

Authors and Affiliations

Haitham Taha
Mahmood Khalil
Download PDF Download RIS Download Bibtex

Abstract

The research paper presents the results of testing the strength and technological properties of molding sand with gypsum binder, the bonding process proceeded: naturally or conventionally. The tests included mass containing (parts by weight): 78 pbw. Grudzeń-Las quartz sand, 22 pbw. plaster gypsum "Dolina Nidy” and 9 pbw. water. Measurements of compressive strength, shear, tensile and bending as well as permeability and looseness were carried out on standard cylindrical samples kept in the air for 1 - 96 hours or dried at 110 oC for 1 - 8 hours. The results of the analysis were analyzed in connection with the mass structure and construction binding bridges warp grains observed with a scanning microscope (SEM). The influence of drying intensity on the bonding process and related mass properties has been demonstrated, especially from the point of view of the possibility of selection and / or intensification of a specific curing method for use in the production of gypsum binger molds and cores.

Go to article

Authors and Affiliations

K. Granat
P. Paduchowicz
A. Dziedzic
M. Jamka
P. Biały
Download PDF Download RIS Download Bibtex

Abstract

Casting is the most economical way of producing parts for many industries ranging from automotive, aerospace to construction towards small appliances in many shares. One of the challenges is the achievement of defect-free cast parts. There are many ways to do this which starts with calculation and design of proper runner system with correct size and number of feeders. The first rule suggests starting with clean melt. Yet, rejected parts can still be found. Although depending on the requirement from the parts, some defects can be tolerated, but in critical applications, it is crucial that no defect should exist that would deteriorate the performance of the part. Several methods exist on the foundry floor to detect these defects. Functional safety criteria, for example, are a must for today's automotive industry. These are not compromised under any circumstances. In this study, based on the D-FMEA (Design Failure Mode and Effect Analysis) study of a functional safety criterion against fuel leakage, one 1.4308 cast steel function block, which brazed-on fuel rail port in fuel injection unit, was investigated. Porosity, buckling, inclusion and detection for leak were carried out by non-destructive test (NDT) methods. It was found that the best practice was the CT-Scan (Computed Tomography) for such applications.
Go to article

Bibliography

[1] Stefanescu, D.M. (2005). Computer simulation of shrinkage related defects in metal castings–a review. International Journal of Cast Metals Research. 18(3), 129-143.
[2] Kweon, E.S., Roh, D.H., Kim, S.B. & Stefanescu, D.M. (2020). Computational modeling of shrinkage porosity formation in spheroidal graphite iron: a proof of concept and experimental validation. International Journal of Metalcasting. 14, 601-609.
[3] Campbell, J. (2015). Complete casting handbook: metal casting processes, metallurgy, techniques and design. Butterworth-Heinemann.
[4] Duckers, (2015). AISI Materials Content Analysis: Final Report.
[5] Meola, C., Squillace, A., Minutolo, F.M.C. & Morace, R.E. (2004). Analysis of stainless steel welded joints: a comparison between destructive and non-destructive techniques. Journal of Materials Processing Technology. 155, 1893-1899.
[6] Menzies I. & Koshy, P. (2009). In-process detection of surface porosity in machined castings. International Journal of Machine Tools and Manufacture. 49(6), 530-535.
[7] Ushakov, V.M., Davydov, D.M. & Domozhirov, L.I. (2011). Detection and measurement of surface cracks by the ultrasonic method for evaluating fatigue failure of metals. Russian Journal of Nondestructive Testing. 47(9), 631-641.
[8] Vazdirvanidis, A., Pantazopoulos, G. & Louvaris, A. (2009). Failure analysis of a hardened and tempered structural steel (42CrMo4) bar for automotive applications. Engineering Failure Analysis. 16(4), 1033-1038.
[9] Gupta, R.K., Ramkumar, P. & Ghosh, B.R. (2006). Investigation of internal cracks in aluminium alloy AA7075 forging. Engineering Failure Analysis. 13(1), 1-8.
[10] Smokvina Hanza S. & Dabo, D. (2017). Characterization of cast iron using ultrasonic testing, HDKBR INFO Mag. 7(1), 3-7.
[11] Krautkrämer, J. & Krautkrämer, H. (1990). Ultrasonic Testing of Materials” Springer-Verlag.
[12] Ziółkowski, G., Chlebus, E., Szymczyk, P. & Kurzac, J. (2014). Application of X-ray CT method for discontinuity and porosity detection in 316L stainless steel parts produced with SLM technology. Archives of Civil and Mechanical Engineering. 14(4), 608-614.
[13] A. du Plessis, A., le Roux, S.G. & Guelpa, A. (2016). Comparison of medical and industrial X-ray computed tomography for non-destructive testing. Case Studies in Nondestructive Testing and Evaluation. 6(A), 17-25.
[14] Kurz, J.H., Jüngert, A., Dugan, S., Dobmann, G. & Boller, C. (2013). Reliability considerations of NDT by probability of detection (POD) determination using ultrasound phased array. Engineering Failure Analysis. 35, 609-617.
[15] Sika, R., Rogalewicz, M., Kroma, A. & Ignaszak, Z. (2020). Open atlas of defects as a supporting knowledge base for cast iron defects analysis. Archives of Foundry Engineering. 20(1), 55-60.

Go to article

Authors and Affiliations

K.C. Dizdar
1
ORCID: ORCID
H. Sahin
1
ORCID: ORCID
M. Ardicli
2
D. Dispinar
3
ORCID: ORCID

  1. Istanbul Technical University, Turkey
  2. Bosch Powertrain Solutions, Bursa, Turkey
  3. Foseco Non-Ferrous Metal Treatment, Netherlands

This page uses 'cookies'. Learn more