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Abstract

Measurements of water temperature and salinity were carried out at 38 oceanographic stations at Admiralty Bay in the period between December 1978 and February 1979. The temperature at the water surface ranged from 0.18°C to 2.81 °C and salinity from 16.40 to 34.16‰. Deeper water temperature decreased and salinity increased ranging at the bottom, at the depth of 480 m, from —0.23°C to 26°C and from 34.51‰ to 34.57‰, respectively. The investigations at the shore and offshore stations showed a marked effect of the run-offs from glaciers causing a considerable decrease in salinity of the thin surface layer of the waters. The main area of the Bay is characterized by high uniformity of water temperature and salinity, which proves that these waters are well mixed.

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Authors and Affiliations

Zygmunt Szafrański
Maciej Lipski
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Abstract

In this study, two different compositions of submicron-structured titanium (760 nm) and micron-structured chromium (4.66 μm) powders were mixed to fabricate Cr-31.2 mass% Ti alloys by vacuum hot-press sintering. The research imposed various hot-press sintering pressures (20, 35 and 50 MPa), while the sintering temperature maintained at 1250°C for 1 h. The experimental results showed that the optimum parameters of the hot-press sintered Cr-31.2 mass% Ti alloys were 1250°C at 50 MPa for 1 h. Also, the relative density reached 99.94%, the closed porosity decreased to 0.04% and the hardness and transverse rupture strength (TRS) values increased to 81.90 HRA and 448.53 MPa, respectively. Moreover, the electrical conductivity is enhanced to 1.58 × 104 S·cm–1. However, the grain growth generated during the high-temperature and high-pressure of the hot-press sintering process resulted in the grain coarsening phenomenon of the Cr-31.2 mass% Ti alloys after 1250°C hot-press sintering at 50 MPa for 1 h. In addition, the Cr-31.2 mass% Ti alloys were fabricated with the submicron-structured titanium (760 nm) and chromium (588 nm) powders showed more effective compaction than the micron-structured titanium (760 nm) and chromium (4.66 μm) powders did. The closed porosity decreases to 0.02% and the hardness values increase to 83.23 HRA. However, the agglomeration phenomenon of the Cr phase and brittleness of the TiCr2 Laves phases easily led to a slight decrease in TRS (400.54 MPa).

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Authors and Affiliations

Shih-Hsien Chang
Chien-Lun Li
Kuo-Tsung Huang
Tzu-Hsien Yang
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Abstract

This work investigates the compaction behaviour of commercial pure aluminium chips (CP Al) produced during a machining operation and subsequently consolidated by Equal Channel Angular Pressing (ECAP). Empirical models were developed to describe the relative density and hardness of the compacted product of ECAP as functions of the initial machining input parameters including cutting edge angle (CA), depth of cut (DOC) and then the number of consolidation pass during ECAP. The models were developed utilizing response surface methodology (RSM) based on data from a central composite face centred factorial design of experiments approach. The models were then validated by using Analysis of Variance (ANOVA). The effect of input parameters on the relative density and hardness of the ECAP consolidated samples are presented and discussed including details as regards to the mechanical and microstructural properties. An optimum set of input parameters are identified and presented where the best relative density and hardness are demonstrated.
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Authors and Affiliations

R. Palanivel
1
ORCID: ORCID
S. Vigneshwaran
2
ORCID: ORCID
A. Alshqirate
3
ORCID: ORCID
R. Madhavan
2
ORCID: ORCID
P. Venkatachalam
4
R.F. Laubscher
5
ORCID: ORCID

  1. Shaqra University, Department of Mechanical Engineering, Saudi Arabia, 11911
  2. National Institute of Technology, Department of Mechanical Engineering, Puducherry, Karaikal – 609 609, India
  3. Department of Mechanical Engineering, Faculty of Engineering Technology, Al-Balqa Applied University, Jordan 19117
  4. Department of Mechanical Engineering, MVJ College of Engineering, Bengaluru – 560 067, Karnataka, India
  5. Department of Mechanical Science & Engineering, University of Johannesburg, South Africa

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