scholarly journals Degradation of Titanium Sintered with Magnesium: Effect of Hydrogen Uptake

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 527
Author(s):  
Vasil M. Garamus ◽  
Wolfgang Limberg ◽  
Maria Serdechnova ◽  
Di Mei ◽  
Sviatlana V. Lamaka ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Chemical Composition ◽  
Room Temperature ◽  
Mechanical Characteristics ◽  
Titanium Implant ◽  
Hydrogen Uptake ◽  
Mechanical Parameters ◽  
Medical Implants ◽  
Titanium Component ◽  
Before And After

Multifunctional materials based on a combination of permanent and degradable metals open new perspectives for medical implants combining osseoconductivity and drug-delivery functions which can significantly decrease the number of implants’ revision. In this work, hybrid magnesium-titanium materials were produced via sintering, and the properties of the permanent titanium component before and after the degradation of the temporary magnesium part were evaluated. The changes of chemical composition and mechanical parameters were determined. Loading of hydrogen into the titanium part at room temperature was observed, which deteriorated the mechanical characteristics but could also simultaneously improve the biocompatibility of the permanent titanium implant. The control of degradation of the magnesium part and the modification of the titanium part are required for the development of partly degradable hybrid implants.

scholarly journals Influence Mechanism of Grouting on Mechanical Characteristics of Rock Mass

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Zhang Jixun ◽  
Shu Jiaqing ◽  
Ren Xuhua ◽  
Ren Hongyun
Keyword(s):  
Composite Material ◽  
Rock Mass ◽  
Constitutional Law ◽  
Damage Mechanics ◽  
Mechanical Characteristics ◽  
Mechanical Parameters ◽  
Cement Slurry ◽  
Influence Mechanism ◽  
Coefficient Of Permeability ◽  
Before And After

Grouting technology has been widely used in all fields of geotechnical and civil engineering. Prospective engineering objectives including reinforcement of rock mass and groundwater leakage treatment can be achieved by grouting which will change the mechanical parameters of rock mass such as strength, elastic modulus, and coefficient of permeability. In this paper, rock mass is assumed as a composite material consisting of rock particles and random microcracks initially. Since part or all of the cracks will be filled with cement slurry after grouting, rock mass consists of rock particles, grout condensate, and some or no random microcracks after grouting. The damage constitutional law of the mesoscopic element is established based on the theory of mesoscopic damage mechanics. With the heterogeneity of the components of rock mass considered, the variation of mechanical characteristics of rock mass is studied before and after grouting. And the influence mechanism of grouting on rock mass is investigated at mesoscale level.

Thermomechanical Treatment of a 4340 Ni-Cr-Mo Alloy Steel

1981 ◽  
Vol 39 ◽  
pp. 314-315 ◽  
Author(s):  
M.T. Jahn ◽  
J.C. Yang ◽  
C.M. Wan
Keyword(s):  
Mechanical Property ◽  
Chemical Composition ◽  
Alloy Steel ◽  
Thermomechanical Treatment ◽  
Room Temperature ◽  
Good Combination ◽  
Thermal Treatments ◽  
Low Carbon ◽  
4340 Steel ◽  
Good Improvement

4340 Ni-Cr-Mo alloy steel is widely used due to its good combination of strength and toughness. The mechanical property of 4340 steel can be improved by various thermal treatments. The influence of thermomechanical treatment (TMT) has been studied in a low carbon Ni-Cr-Mo steel having chemical composition closed to 4340 steel. TMT of 4340 steel is rarely examined up to now. In this study we obtain good improvement on the mechanical property of 4340 steel by TMT. The mechanism is explained in terms of TEM microstructures4340 (0.39C-1.81Ni-0.93Cr-0.26Mo) steel was austenitized at 950°C for 30 minutes. The TMTed specimen (T) was obtained by forging the specimen continuously as the temperature of the specimen was decreasing from 950°C to 600°C followed by oil quenching to room temperature. The thickness reduction ratio by forging is 40%. The conventional specimen (C) was obtained by quenching the specimen directly into room temperature oil after austenitized at 950°C for 30 minutes. All quenched specimens (T and C) were then tempered at 450, 500, 550, 600 or 650°C for four hours respectively.

Weldability - Behavior of Welded Reinforcement

2019 ◽  
Vol 70 (10) ◽  
pp. 3469-3472
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Mechanical Characteristics ◽  
Mechanical Performance ◽  
Current Work ◽  
Carbon Equivalent ◽  
Work Process ◽  
Ultimate Limit

Weldability involves two aspects: welding behavior of components and safety in operation. The two aspects will be reduced to the mechanical characteristics of the elements and to the chemical composition. In the case of steel reinforcing rebar’s, it is reduces to the percentage of Cech(carbon equivalent) and to the mechanical characteristics: the yielding limit, the ultimate limit, and the elongations which after that represent the ductility class in which the re-bars is framed. The paper will present some types of steel reinforcing rebar’s with its mechanical characteristics and the welding behavior of those elements. In the current work, process-related behavior of welded reinforcement, joint local and global mechanical properties, and their correlation with behavior of normal reinforcement and also the mechanical performance resulted in this type of joints. Keywords: welding behavior, ultimate limit, reinforcing rebar’s

scholarly journals On the measurement of the ratio of the specific heats using small volumes of gas.—The ratios of the specific heat of air and of hydrogen at atmospheric pressure and a temperatures between 20°C. and —183°C

1925 ◽  
Vol 107 (743) ◽  
pp. 510-543 ◽  
Keyword(s):  
Systematic Error ◽  
Low Temperatures ◽  
Room Temperature ◽  
Expansion Chamber ◽  
Small Vessels ◽  
Specific Heats ◽  
Large Expansion ◽  
Before And After ◽  
The One ◽  
Chamber Capacity

Introduction .—In nearly all the previous determinations of the ratio of the specific heats of gases, from measurements of the pressures and temperature before and after an adiabatic expansion, large expansion chambers of fror 50 to 130 litres capacity have been used. Professor Callendar first suggests the use of smaller vessels, and in 1914, Mercer (‘Proc. Phys. Soc.,’ vol. 26 p. 155) made some measurements with several gases, but at room temperature only, using volumes of about 300 and 2000 c. c. respectively. He obtained values which indicated that small vessels could be used, and that, with proper corrections, a considerable degree of accuracy might be obtained. The one other experimenter who has used a small expansion chamber, capacity about 1 litre, is M. C. Shields (‘Phys. Rev.,’ 1917), who measured this ratio for air and for hydrogen at room temperature, about 18° C., and its value for hydroger at — 190° C. The chief advantage gained by the use of large expansion chambers is that no correction, or at the most, a very small one, has to be made for any systematic error due to the size of the containing vessels, but it is clear that, in the determinations of the ratio of the specific heats of gases at low temperatures, the use of small vessels becomes a practical necessity in order that uniform and steady temperature conditions may be obtained. Owing, however, to the presence of a systematic error depending upon the dimensions of the expansion chamber, the magnitude of which had not been definitely settled by experiment, the following work was undertaken with the object of investigating the method more fully, especially with regard to it? applicability to the determination of this ratio at low temperatures.

Carbon Capture Performance of Amino-Modified MIL-101 at Room Temperature

2013 ◽  
Vol 395-396 ◽  
pp. 637-640
Author(s):  
Yi Yang ◽  
Zheng Ping Wang ◽  
Ling Meng ◽  
Lian Jun Wang
Keyword(s):  
Carbon Dioxide ◽  
Specific Surface ◽  
Pore Structure ◽  
Carbon Capture ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Metal Organic Framework ◽  
Adsorption Properties ◽  
Carbon Dioxide Adsorption ◽  
Before And After

MIL-101, a metal-organic framework material, was synthesized by the high-temperature hydrothermal method. Triethylenetetramine (TETA) modification enabled the effective grafting of an amino group onto the surface of the materials and their pore structure. The crystal structure, micromorphology, specific surface area, and pore structure of the samples before and after modification were analyzed with an X-ray diffractometer, scanning electron microscope, specific surface and aperture tester, and infrared spectrometer. The carbon dioxide adsorption properties of the samples were determined by a thermal analyzer before and after TETA modification. Results show that moderate amino modification can effectively improve the microporous structure of MIL-101 and its carbon dioxide adsorption properties. After modification, the capacity of MIL-101 to adsorb carbon dioxide decreased only by 0.61 wt%, and a high adsorption capacity of 9.45 wt% was maintained after six cycles of adsorption testing at room temperature and ambient pressure.

Mechanical Behavior for some Cobalt Alloys

2015 ◽  
Vol 1114 ◽  
pp. 9-12
Author(s):  
Alexandru Ghiban ◽  
Brandusa Ghiban ◽  
Cristina Maria Borţun ◽  
Nicolae Serban ◽  
Mihai Buzatu
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Mechanical Behavior ◽  
Mechanical Characteristics ◽  
Fractographic Analysis ◽  
Cobalt Alloys ◽  
Dental Alloys ◽  
Bending Tests ◽  
Longitudinal Modulus

Four compositions of some usually commercial dental alloys were investigated in order to determine the mechanical characteristics and fractographic analysis of tensile and bending tests surfaces. A correlation between chemical composition (either molybdenum or molybdenum and chromium contents) and mechanical characteristics (longitudinal modulus, tensile strength and elongation) were finally done.

A New Hafnium-Beryllium System Prioduced by Ion Implantation and Annealing Techniques

1983 ◽  
Vol 27 ◽  
Author(s):  
J.C. Soares ◽  
A.A. Melo ◽  
M.F. DA Silva ◽  
E.J. Alves ◽  
K. Freitag ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Single Crystals ◽  
Room Temperature ◽  
Low Dose ◽  
Correlation Method ◽  
High Dose ◽  
Tetrahedral Sites ◽  
Time Differential ◽  
Before And After ◽  
Beryllium Foil

ABSTRACTLow and high dose hafnium imolanted beryllium samoles have been prepared at room temperature by ion implantation of beryllium commercial foils and single crystals. These samples have been studied before and after annealing with the time differential perturbed angular correlation method (TDPAC) and with Rutherford backscattering and channeling techniques. A new metastable system has been discovered in TDPAC-measurements in a low dose hafnium implanted beryllium foil annealed at 500°C. Channeling measurements show that the hafnium atoms after annealing, are in the regular tetrahedral sites but dislocated from the previous position occupied after implantation. The formation of this system is connected with the redistribution of oxygen in a thin layer under the surface. This effect does not take place precisely at the same temperature in foils and in single crystals.

Utility of current sialendoscopes in the sinonasal cavity

2015 ◽  
Vol 129 (9) ◽  
pp. 870-873
Author(s):  
C R Kieliszak ◽  
T R Khoury ◽  
A Singh ◽  
A S Joshi
Keyword(s):  
Drug Delivery ◽  
Minimally Invasive ◽  
Paranasal Sinuses ◽  
Sphenoid Sinus ◽  
Mucosal Biopsy ◽  
Before And After ◽  
Invasive Method ◽  
Cannulation Success ◽  
Cadaveric Model ◽  
Sphenoid Sinuses

AbstractObjectives:This study assessed the utility of current sialendoscopes in the paranasal sinuses in a cadaveric model and evaluated novel uses for sialendoscopes.Methods:Currently available sialendoscopes were used for visualisation and performing interventions in the paranasal sinuses. Ten cadaver heads were studied before and after dissection. Outcomes included ostia identification, sinus cannulation, success of mucosal biopsy collection and image clarity.Results:Marchal and Erlangen sialendoscopes were found to be effective for both visualising and cannulating the sphenoid sinuses before and after dissection. Both types demonstrated poor maxillary ostia visualisation without dissection, but did allow treatment after antrostomy. Larger diameter sialendoscopes were associated with the lowest image distortion during maxillary ostia assessment. Mucosal biopsy collection within the sphenoid sinus, but not in the maxillary sinus, was possible before dissection.Conclusion:Sialendoscopes can be used for visualisation and performing interventions in the sinonasal cavity, but their utility is mainly limited to the sphenoid sinus. They may be considered a minimally invasive method for drug delivery and/or biopsy collection in the post-operative setting for all sinuses. Design improvements are suggested.

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