Surface roughness and hardness of yttria stabilized zirconia (Y-TZP after 10 years of simulated brushing

Directory of Open Access Journals (Sweden)

Lucas Miguel Candido

Full Text Available Introduction: The Y-TZP zirconia used for prosthetic infrastructure, in some clinical situations, can be exposed to the oral environment. In these situations, a polished surface without changes is extremely important. Objective: The aim of this study was to evaluate the mean roughness (Ra and Vickers hardness of Y-TZP zirconia (Lava™ after simulating ten years of brushing. Material and method: Thirty-six Y-TZP bar-shaped specimens (20mm X 4mm X 1.2mm were divided into three groups: storage in distilled water (DW, n=12, control; brushing with distilled water (BDW, n=12 and brushing with distilled water and fluoride toothpaste (BFT, n=12. Brushing was performed using a brushing machine with a soft-bristled toothbrush, simulating 10 years of brushing (878.400 cycles, 100gf. The mean roughness (Ra in μm and Vickers hardness (VHN of all specimens were measured twice: before and after the experimental treatment, in profilometer and microhardness tester (500gf, 30 seconds, respectively. Data were analyzed using the two-way ANOVA test (α = 0.05. Result: The interaction between groups was not significant for roughness (p = 0.701 nor for hardness (p = 0.928. The final averages for Ra (μm were equal to: DW - 0.63; BDW - 0.64; and, BFT - 0.68. The final averages for Vickers hardness (VHN were: DW - 1301.16; BDW - 1316.60; and, BFT - 1299.58. Conclusion: It was concluded that the brushing with distilled or fluoridated toothpaste was not able to change the roughness and hardness of Y-TZP zirconia used in this study.

In Vitro Comparative Study of Two Different Bleaching Agents on Micro-hardness Dental Enamel.

Science.gov (United States)

Fatima, Nazish; Ali Abidi, Syed Yawar; Meo, Ashraf Ali

2016-02-01

To evaluate the effect of home-use bleaching agent containing 16% Carbamide Peroxide (CP) and in-office bleaching agent containing 38% Hydrogen Peroxide (HP) on enamel micro-hardness. An in vitroexperimental study. Department of Operative Dentistry and Science of Dental Materials at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences and Material Engineering Department of NED University of Engineering and Technology, Karachi, from July to December 2014. Atotal of 90 enamel slabs from 45 sound human 3rd molar were randomly divided into 3 groups. Each group contained 30 specimens (n=30). Group 1 was kept in artificial saliva at 37°C in incubator during the whole experiment. However, Groups 2 and 3 were treated with power whitening gel and tooth whitening pen respectively. After bleaching session, specimens were thoroughly rinsed with deionized water again for 10 seconds and then stored in artificial saliva at 37°C in incubator. Artificial saliva was changed after every 2 days. The Vickers hardness tester (Wolpert 402 MVD, Germany) was adjusted to a load of 0.1 kg (100 gm) and dwell time of 5 seconds. Three Vickers were performed on each specimen using a hardness tester according to the ISO 6507-3:1998 specification. Micro-hardness measurements were performed before and after bleaching at day 1, 7 and 14. In the control group, the baseline micro-hardness was 181.1 ±9.3 which was reduced after the storage on day 1, 7 and 14 (p = 0.104). In Group 2, baseline micro-hardness was 180.4 ±10.1 which was reduced to 179.79 ±10.0 units after day 1. Whereas, on day 7 and 14, the values of micro-hardness were 179.8 ±10 and 179.7 ±10.29, respectively (p=0.091). Furthermore, the baseline micro-hardness in Group 3 was 174.0 ±22.9 units which was reduced to 173 ±23 on day 1, 170 ±30 on day 7 and 173 ±23 on day 14 (p = 0.256). The statistically insignificant difference was found among micro-hardness values of different bleaching

In Vitro Comparative Study of Two Different Bleaching Agents on Micro-hardness Dental Enamel

International Nuclear Information System (INIS)

Fatima, N.; Abidi, S. Y. A.; Meo, A. A.

2016-01-01

Objective: To evaluate the effect of home-use bleaching agent containing 16 percentage Carbamide Peroxide (CP) and in-office bleaching agent containing 38 percentage Hydrogen Peroxide (HP) on enamel micro-hardness. Study Design: An in vitro experimental study. Place and Duration of Study: Department of Operative Dentistry and Science of Dental Materials at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences and Material Engineering Department of NED University of Engineering and Technology, Karachi, from July to December 2014. Methodology: A total of 90 enamel slabs from 45 sound human 3rd molar were randomly divided into 3 groups. Each group contained 30 specimens (n=30). Group 1 was kept in artificial saliva at 37 Degree C in incubator during the whole experiment. However, Groups 2 and 3 were treated with power whitening gel and tooth whitening pen respectively. After bleaching session, specimens were thoroughly rinsed with deionized water again for 10 seconds and then stored in artificial saliva at 37 Degree C in incubator. Artificial saliva was changed after every 2 days. The Vickers hardness tester (Wolpert 402 MVD, Germany) was adjusted to a load of 0.1 kg (100 gm) and dwell time of 5 seconds. Three Vickers were performed on each specimen using a hardness tester according to the ISO 6507-3:1998 specification. Micro-hardness measurements were performed before and after bleaching at day 1, 7 and 14. Results: In the control group, the baseline micro-hardness was 181.1 ± 9.3 which was reduced after the storage on day 1, 7 and 14 (p = 0.104). In Group 2, baseline micro-hardness was 180.4 ±10.1 which was reduced to 179.79 ± 10.0 units after day 1. Whereas, on day 7 and 14, the values of micro-hardness were 179.8 ±10 and 179.7 ±10.29, respectively (p=0.091). Furthermore, the baseline micro-hardness in Group 3 was 174.0 ±22.9 units which was reduced to 173 ± 23 on day 1, 170 ±30 on day 7 and 173 ± 23 on day 14 (p = 0

Investigation of stand-off distance effect on structure, adhesion and hardness of copper coatings obtained by the APS technique

Science.gov (United States)

Masoumeh, Goudarzi; Shahrooz, Saviz; Mahmood, Ghoranneviss; Ahmad, Salar Elahi

2018-03-01

The outbreak of the disease and infection in the hospital environment and medical equipment is one of the concerns of modern life. One of the effective ways for preventing and reducing the complications of infections is modification of the surface. Here, the handmade atmospheric plasma spray system is used for accumulating copper as an antibacterial agent on the 316L stainless steel substrate, which applies to hospital environment and medical equipment. As a durable coating with proper adhesion is needed on the substrate, the effect of stand-off distance (SOD) which is an important parameter of the spray on the microstructure, the hardness and adhesion of the copper coating on the 316L stainless steel were investigated. The structure and phase composition of copper depositions were investigated using scanning electron microscopy and X-ray diffraction. The adhesion and hardness of depositions are evidenced using the cross cut tester and Vickers hardness tester, respectively. The findings confirm that the voids in the coatings increase with increasing SOD, which leads to decreasing the hardness of coatings and also the adhesion strength between depositions and substrate. In addition, by increasing the SOD, the oxygen content and the size of grains in the lamellae (fine structure) of coatings also increase.

Thermomechanical Properties of Sb2O3-TeO2-V2O5 Glassy Systems: Thermal Stability, Glass Forming Tendency and Vickers Hardness

Science.gov (United States)

Souri, Dariush; Torkashvand, Ziba

2017-04-01

Three-component 40TeO2-(60- x)V2O5- xSb2O3 glasses with 0 ≤ x ≤ 10 (in mol.%) were obtained by the rapid melt-quenching method. These glasses were studied with respect to some mechanical properties with the goal of obtaining information about their structure. The Vickers hardness test was employed to obtain Vickers micro-hardness ( H V) at two different loads, which was within the range of 13.187-17.557 GPa for a typical 0.1 HV (0.9807 N) load. In addition, theoretical micro-hardness ( H) was investigated and compared with experimental H V, showing the elevating trend with increase of Sb2O3 content, as for H V. Furthermore, differential scanning calorimetry (DSC) was employed within the range of 150-500°C at heating rates of φ = 3 K/min, 6 K/min, 9 K/min, 10 K/min, and 13 K/min. In this work, thermal stability ( T s = T cr - T x) and glass forming tendency ( K gl) were measured and reported for these glasses to determine the relationship between the chemical composition and the thermal stability, in order to interpret the structure of glass. Generally, from the ascertained outputs [analysis of mechanical data, titration study, the values of reduced fraction of vanadium ions ( C V) and oxygen molar volume ( V_{{O}}^{*} )], it was found that the micro-hardness had an increasing trend with increasing the Sb2O3 content. Among the studied glasses, the sample with x = 8 had a higher average micro-hardness value, the highest average thermal stability and glass forming tendency with respect to the other samples, which makes it a useful material (owning very good resistance against thermal attacks) for device manufacturing.

Vickers microhardness studies on solution-grown single crystals of potassium boro-succinate

Science.gov (United States)

Lakshmipriya, M.; Rajan Babu, D.; Ezhil Vizhi, R.

2015-02-01

The semiorganic crystals of potassium boro-succinate (KBS) were grown by slow evaporation method. KBS crystallizes in monoclinic system which was confirmed by powder XRD analysis. Vickers microhardness study has been carried out over a load range of 25-100 g. The Vickers hardness numbers (Hv) of the material increases as the load increases so the material is suitable for device fabrication. The Meyer index 'n' is estimated to be greater than 1.6, the crystal system belongs to the soft material category. The elastic stiffness coefficient, c11, has also been calculated using Wooster's empirical relation from the hardness data. The fracture toughness values 'Kc', determined from measurements of crack lengths, were estimated to be 0.15166 MN/m3/2. The brittleness indices 'Bi' were estimated as 276 m-1/2.

Effect of Substrate Bias on Friction Coefficient, Adhesion Strength and Hardness of TiN-COATED Tool Steel

Science.gov (United States)

Hamzah, Esah; Ali, Mubarak; Toff, Mohd Radzi Hj. Mohd

In the present study, TiN coatings have been deposited on D2 tool steel substrates by using cathodic arc physical vapor deposition technique. The objective of this research work is to determine the usefulness of TiN coatings in order to improve the micro-Vickers hardness and friction coefficient of TiN coating deposited on D2 tool steel, which is widely used in tooling applications. A Pin-on-Disc test was carried out to study the coefficient of friction versus sliding distance of TiN coating deposited at various substrate biases. The standard deviation parameter during tribo-test result showed that the coating deposited at substrate bias of -75 V was the most stable coating. A significant increase in micro-Vickers hardness was recorded, when substrate bias was reduced from -150 V to zero. Scratch tester was used to compare the critical loads for coatings deposited at different bias voltages and the adhesion achievable was demonstrated with relevance to the various modes, scratch macroscopic analysis, critical load, acoustic emission and penetration depth. A considerable improvement in TiN coatings was observed as a function of various substrate bias voltages.

Penetration Tester's Open Source Toolkit

CERN Document Server

Faircloth, Jeremy

2011-01-01

Great commercial penetration testing tools can be very expensive and sometimes hard to use or of questionable accuracy. This book helps solve both of these problems. The open source, no-cost penetration testing tools presented do a great job and can be modified by the user for each situation. Many tools, even ones that cost thousands of dollars, do not come with any type of instruction on how and in which situations the penetration tester can best use them. Penetration Tester's Open Source Toolkit, Third Edition, expands upon existing instructions so that a professional can get the most accura

The relationship between the hardness and the point-defect-density in neutron-irradiated MgO·3.0Al2O3 and AlN

International Nuclear Information System (INIS)

Suematsu, H.; Yatsui, K.; Yano, T.

2001-01-01

MgO·3.0Al 2 O 3 single crystals and sintered AlN polycrystals were irradiated with fast neutrons in various conditions and the hardness of the irradiated and unirradiated samples was measured with a Vickers hardness tester. The hardness of as-irradiated MgO·3.0Al 2 O 3 and AlN samples increased by 23 and 51%, respectively. After isochronal annealing, the hardness gradually decreased and mostly recovered to that of the unirradiated one up to 1400degC. Volume of the sample also increased after the irradiation and changed in the same way as the hardness by annealing. A relationship between the hardness and the density of point defects is proposed and the experimental results agree with the relationship. It implies that the point defects generated by the irradiation pin down dislocations and increase the hardness of neutron irradiated MgO·3.0Al 2 O 3 samples. (author)

Accelerated aging effects on surface hardness and roughness of lingual retainer adhesives.

Science.gov (United States)

Ramoglu, Sabri Ilhan; Usumez, Serdar; Buyukyilmaz, Tamer

2008-01-01

To test the null hypothesis that accelerated aging has no effect on the surface microhardness and roughness of two light-cured lingual retainer adhesives. Ten samples of light-cured materials, Transbond Lingual Retainer (3M Unitek) and Light Cure Retainer (Reliance) were cured with a halogen light for 40 seconds. Vickers hardness and surface roughness were measured before and after accelerated aging of 300 hours in a weathering tester. Differences between mean values were analyzed for statistical significance using a t-test. The level of statistical significance was set at P statistically significant (P statistically significant (P .05). Accelerated aging significantly increased the surface microhardness of both light-cured retainer adhesives tested. It also significantly increased the surface roughness of the Transbond Lingual Retainer.

The effect of acidulated phosphate fluoride application on dental enamel surfaces hardness

Directory of Open Access Journals (Sweden)

Edhie Arief P

2007-09-01

Full Text Available Enamel demineralization by acid is the first step of caries process. It has recently been shown that acidulated phosphate fluoride (APF can maintain the hardness of enamel surface. The aim of this study was examine the effect of APF application in the hardest of enamel surface. Fifty extracted teeth were cut at their crown, 40 teeth were taken randomly then divided into 4 groups, group 1 as the control, group 2 was treated with APF for 1 minute, group 3 for 4 minutes and group 4 for 7 minutes, then all the samples were washed with demineralized water. To see the effect of APF, all of the samples were soaked in lactic acid demineralization solution with pH 4,5 for 72 hours., the hardness of the surfaces of those samples before and after the treatment was measured by Micro Vickers Hardness Tester. The data were analyzed using One-Way ANOVA and LSD tests. In conclusion, 1.23% APF gel can reduce higher enamel demineralization.

Surface hardness of hybrid ionomer cement after immersion in antiseptic solution

Directory of Open Access Journals (Sweden)

Anita Yuliati

2006-06-01

Full Text Available Hybrid ionomer cement or resin modified glass ionomer cement is a developed form of conventional glass ionomer cement. This hybrid ionomer cement can be eroded if in direct contact with acid solution which will affect surface hardness. The aim of this study is to learn surface hardness of hybrid ionomer cement after immersion in methyl salicylate 0.06% (pH 3.6 and povidon iodine 1% (pH 2.9 solution. Sample of hybrid ionomer cement with 5 mm diameter and 3 mm thickness was immersed in sterile aquadest solution (control, methyl salicylate pH 3.6, povidon iodine pH 2.9 for 1 minute, 7 and 14 minutes. Surface hardness was measured with Micro Vickers Hardness Tester. The obtained data was analyzed statistically with ANOVA followed by LSD test. The result of hybrid ionomer cement after immersion in sterile aquadest, methyl salicylate 0.06% pH 3.6 and povidon iodine 1% pH 2.9 for one minute, showed no significant difference; while immersion for 7 and 14 minutes showed a significant difference. The conclusion states that hybrid ionomer cement after 14 minutes immersion in povidon iodine 1% pH 2.9 has the lowest surface hardness.

The effect of nitrogen gas flow rate on heat treatment of AISI SS-430: Study of microstructure and hardness

Science.gov (United States)

Sebayang, Perdamean; Darmawan, Bobby Aditya; Simbolon, Silviana; Alfirano, Sudiro, Toto; Aryanto, Didik

2018-05-01

The aim of this research was to obtain the austenite phase from ferritic stainless steel through sample heat treatment. The AISI 430 ferritic steel with the thickness of about 0.4 mm was used. The heat treatment was conducted in a tube furnace at elevated temperature of 1150, 1200, 1250 °C and nitrogen gas flow rate of 0.57 and 0.73 l/s. The samples were then rapidly quenched in water bath. An optical microscope, XRD, SEM-EDS and micro vickers hardness tester were used to characterize the sample before and after het treatment. The presence of anneal twins indicated the formation of austenite phase in the sample. Its fraction was varied from 10.89 wt% to 35.10 wt%. In addition, the heat treatment temperature strongly affected the sample hardness. The optimum hardness obtained was about 542.69 HV. According to the results, this material can be considered for biomedical applications.

Comparison of time-dependent changes in the surface hardness of different composite resins

Science.gov (United States)

Ozcan, Suat; Yikilgan, Ihsan; Uctasli, Mine Betul; Bala, Oya; Kurklu, Zeliha Gonca Bek

2013-01-01

Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vicker's hardness tester. The samples were then stored at 37°C and 100% humidity. After 24 h and 7, 30 and 90 days, the top and bottom surface hardness of the samples was measured. In each measurement, the rate between the hardness of the top and bottom surfaces were recorded as the hardness rate. Statistical analysis was performed by one-way analysis of variance, multiple comparisons by Tukey's test and binary comparisons by t-test with a significance level of P = 0.05. Results: The highest hardness values were obtained from each two surfaces of Majesty Posterior and the lowest from Filtek Silorane. Both the top and bottom surface hardness of the methacrylate based composite resins was high and there was a statistically significant difference between the top and bottom hardness values of only the silorane-based composite, Filtek Silorane (P composite resin Filtek Silorane showed adequate hardness ratio, the use of incremental technic during application is more important than methacrylate based composites. PMID:24966724

Laser surface melting of 304 stainless steel for pitting corrosion resistance improvement

CSIR Research Space (South Africa)

Seleka, TS

2006-11-01

Full Text Available optical emission spectroscopy (GDOES) was utilized for chemical analysis. Changes in hardness were observed by using a Vickers microhardness tester. Pitting corrosion tests on laser treated and untreated samples were conducted according to ASTM G48...

Micro-hardness of non-irradiated uranium dioxide

International Nuclear Information System (INIS)

Kim, Sung-Sik; Takagi, Osamu; Obata, Naomi; Kirihara, Tomoo.

1983-01-01

In order to obtain the optimum conditions for micro-hardness measurements of sintered UO 2 , two kinds of hardness tests (Vickers and Knoop) were examined with non-irradiated UO 2 of 2.5 and 5 μm in grain size. The hardness values were obtained as a function of the applied load in the load range of 25 -- 1,000 g. In the Vickers test, cracks were generated around the periphery of an indentation even at lower load of 50 g, which means the Vickers hardness is not suitable for UO 2 specimens. In the Knoop test, three stages of load dependence were observed for sintered pellet as well as for a single crystal by Bates. Load dependence of Knoop hardness and crack formation were discussed. In the range of applied load around 70 -- 100 g there were plateau region where hardness values were nearly unchanged and did not contain any cracks in the indentation. The plateau region represents a hardness of a specimen. From a comparison between the hardness values of 2.5 μm and those of 5 μm UO 2 , it was approved that the degree of sintering controls the hardness in the plateau region. (author)

Interaction between Yttria fully stabilized Zirconia or Yttria-Zirconia blended face-coat with Ti6Al4V during investment casting

CSIR Research Space (South Africa)

Mutombo, K

2014-10-01

Full Text Available The interaction between the Ti6Al4V alloy and the mould materials was investigated. The alpha-case was characterized by Vickers hardness tester, optical and scanning electron microscopy equipped with electron dispersive X-ray spectrometry (EDX). X-ray...

Elasticity and hardness of nano-polycrystalline boron nitrides: The apparent Hall-Petch effect

International Nuclear Information System (INIS)

Nagakubo, A.; Ogi, H.; Hirao, M.; Sumiya, H.

2014-01-01

Nano-polycrystalline boron nitride (BN) is expected to replace diamond as a superhard and superstiff material. Although its hardening was reported, its elasticity remains unclear and the as-measured hardness could be significantly different from the true value due to the elastic recovery. In this study, we measured the longitudinal-wave elastic constant of nano-polycrystalline BNs using picosecond ultrasound spectroscopy and confirmed the elastic softening for small-grain BNs. We also measured Vickers and Knoop hardness for the same specimens and clarified the relationship between hardness and stiffness. The Vickers hardness significantly increased as the grain size decreased, while the Knoop hardness remained nearly unchanged. We attribute the apparent increase in Vickers hardness to the elastic recovery and propose a model to support this insight.

Effect of Interlayer Coating Thickness on the Hardness and Adhesion for the Tungsten Carbide Cutting Tool

Directory of Open Access Journals (Sweden)

Kamil Jawad Kadhim

2017-12-01

Full Text Available The thin film of the (Al,TiN coating is studied with the aid of two parameters: hardness and adhesion.  These parameters are very close to each other; however, in deposition field they could be interpreted differently.  Several coatings of (Al,TiN layers are developed on tungsten carbide insert using the standard commercial Al0.67Ti0.33 cathodes in cathodic arc plating system(PVD. The influence of coating layer thickness on the mechanical properties of the coatings was investigated via two parameters: hardness and adhesion are characterized by the Rockwell tester Vickers tester.  The measurements reveal that the highest hardness appears for the (Al,TiN thickness of 5.815 µm while the highest adhesion appears at a thickness of 3.089 µm.  At the opposite extreme, the lowest hardness appears at 2.717 µm and the lowest hardness at 5.815 µm. Overall, the (Al/Ti N coating of the thickness of 5.815 µm is controversial as it exhibits the highest hardness and the lowest adhesion. This result could be related to the effect of the formation of the micro-particle (MPs which has a direct effect on the hardness because these MPs appear mainly on the surface and their presence at the interface is very limited.  In addition, the creation of Ti buffering layer to reduce the delamination has its major effect on the adhesion but has no effect on the morphology of the surface.  For these two reasons and the effect of the bias voltage, the results presented in this paper might show slight differences with other published papers.  The composition of the (Al,TiN layer is characterized and, seemingly, it shows one important result which is showing that the ultimate composition of the (Al,TiN layer (Ti0.62Al0.38 is very close to the original target used in this study (Al0.67Ti0.33.

Final report on COOMET Vickers PTB/VNIIFTRI key comparison (COOMET.M.H-K1.b and COOMET.M.H-K1.c)

Science.gov (United States)

Aslanyan, E.; Herrmann, K.

2013-01-01

This report describes a COOMET key comparison on Vickers hardness scales of two National Metrology Institutes—PTB and VNIIFTRI. The pilot laboratory was PTB, which was the linking institute with the key comparison reference values of CCM.H-K1. In the key comparison two sets of hardness reference blocks for the Vickers hardness scales HV1 and HV30, each consisting of three hardness reference blocks with the hardness levels 240 HV, 540 HV and 840 HV, are used. The same hardness reference blocks were used previously in the key comparison CCM.H-K1. The measurement results and uncertainty assessments, announced by VNIIFTRI, are in good agreement with the key comparison reference values of CCM.H-K1. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Enhancing the Hardness of Sintered SS 17-4PH Using Nitriding Process for Bracket Orthodontic Application

Science.gov (United States)

Suharno, B.; Supriadi, S.; Ayuningtyas, S. T.; Widjaya, T.; Baek, E. R.

2018-01-01

Brackets orthodontic create teeth movement by applying force from wire to bracket then transferred to teeth. However, emergence of friction between brackets and wires reduces load for teeth movement towards desired area. In order to overcome these problem, surface treatment like nitriding chosen as a process which could escalate efficiency of transferred force by improving material hardness since hard materials have low friction levels. This work investigated nitriding treatment to form nitride layer which affecting hardness of sintered SS 17-4PH. The nitride layers produced after nitriding process at various temperature i.e. 470°C, 500°C, 530°C with 8hr holding time under 50% NH3 atmosphere. Optical metallography was conducted to compare microstructure of base and surface metal while the increasing of surface hardness then observed using vickers microhardness tester. Hardened surface layer was obtained after gaseous nitriding process because of nitride layer that contains Fe4N, CrN and Fe-αN formed. Hardness layers can achieved value 1051 HV associated with varies thickness from 53 to 119 μm. The presence of a precipitation process occurring in conjunction with nitriding process can lead to a decrease in hardness due to nitrogen content diminishing in solid solution phase. This problem causes weakening of nitrogen expansion in martensite lattice.

Anisotropy of hardness and laser damage threshold of unidirectional organic NLO crystal in relation to the internal structure

International Nuclear Information System (INIS)

Natarajan, V.; Arivanandhan, M.; Sankaranarayanan, K.; Hayakawa, Y.

2011-01-01

Highlights: · Growth rate of the unidirectional organic crystals were measured and the variation in the growth rate was explained based on the attachment energy model. · Anisotropic behaviors of hardness and laser damage threshold of the unidirectional materials were analyzed. · The obtained results were explained based on the crystal structure of the material. - Abstract: Unidirectional benzophenone crystals were grown along , and directions by uniaxially solution crystallization method at ambient temperature. The growth rate of the grown crystals was varied with orientation. The optical absorption coefficients of benzophenone were measured as a function of wavelength. The optical absorption study reveals that the benzophenone crystal has very low absorption in the wavelength range of interest. Moreover, the laser damage threshold and micro hardness for , and oriented unidirectional benzophenone crystals were measured using a Q-switched Nd:YAG laser operating at 1064 nm radiation and Vicker's micro hardness tester, respectively. The laser damage threshold is larger for the and oriented crystals compared to oriented crystal at 1064 nm wavelength. The result is consistent with the hardness variation observed for the three different crystallographic directions of benzophenone crystal. The relation between the laser damage profile and mechanical hardness anisotropy is discussed based on the crystal structure of benzophenone.

Measurement of elastic modulus and Vickers hardness of surround bone implant using dynamic microindentation--parameters definition.

Science.gov (United States)

Soares, Priscilla Barbosa Ferreira; Nunes, Sarah Arantes; Franco, Sinésio Domingues; Pires, Raphael Rezende; Zanetta-Barbosa, Darceny; Soares, Carlos José

2014-01-01

The clinical performance of dental implants is strongly defined by biomechanical principles. The aim of this study was to quantify the Vicker's hardness (VHN) and elastic modulus (E) surround bone to dental implant in different regions, and to discuss the parameters of dynamic microindantion test. Ten cylindrical implants with morse taper interface (Titamax CM, Neodent; 3.5 mm diameter and 7 mm a height) were inserted in rabbit tibia. The mechanical properties were analyzed using microhardness dynamic indenter with 200 mN load and 15 s penetration time. Seven continuous indentations were made distancing 0.08 mm between each other perpendicularly to the implant-bone interface towards the external surface, at the limit of low (Lp) and high implant profile (Hp). Data were analyzed by Student's t-test (a=0.05) to compare the E and VHN values obtained on both regions. Mean and standard deviation of E (GPa) were: Lp. 16.6 ± 1.7, Hp. 17.0 ± 2.5 and VHN (N/mm2): Lp. 12.6 ± 40.8, Hp. 120.1 ± 43.7. No statistical difference was found between bone mechanical properties of high and low profile of the surround bone to implant, demonstrating that the bone characterization homogeneously is pertinent. Dynamic microindantion method proved to be highly useful in the characterization of the individual peri-implant bone tissue.

Evaluation of thermal aging effect on primary pipe material in nuclear power plant by micro hardness test method

International Nuclear Information System (INIS)

Xue Fei; Yu Weiwei; Wang Zhaoxi; Ma Qinzheng; Liu Wei

2012-01-01

The investigation was carried out on the changes in mechanical properties of the primary pipe material Z3CN20.09M after 10000 h aging at 400℃ by using micro- Vickers and impact testing machine. The results show that the impact energy of testing material decreases. However, the micro-Vickers hardness of ferrite phase and austenite phase which constitute the testing material increase and keep constant, respectively. The intrinsic relations were analyzed between the micro-Vickers hardness and the impact energy to make an attempt to present the micro-Vickers hardness measurement as a method applicable to evaluating the thermal aging of the primary pipe material. (authors)

Evaluation of WC-9Co-4Cr laser surface alloyed coatings on stainless steel

CSIR Research Space (South Africa)

Obadele, A

2011-07-01

Full Text Available spectrometer (EDS), while the phase changed were observed using x-ray diffraction (XRD). The surface hardness was determined using the Vickers microhardness tester. The decomposition of WC-9Co-4Cr into W2C, C and W is as a result of low heat of formation of WC...

Textural and morphological studies on zinc–iron alloy electrodeposits

Indian Academy of Sciences (India)

ness of the coating was measured in Vicker's hard- ness number (VHN) by static indentation method, using. Leco microhardness tester (Model M 400) at a given load for 15 seconds time duration. X-ray diffraction pat- terns were taken by using JEOL PANalytical, X' per. PRO model. Samples were scanned between 20. ◦ and.

FPGA-based Bit-Error-Rate Tester for SEU-hardened Optical Links

CERN Document Server

Detraz, S; Moreira, P; Papadopoulos, S; Papakonstantinou, I; Seif El Nasr, S; Sigaud, C; Soos, C; Stejskal, P; Troska, J; Versmissen, H

2009-01-01

The next generation of optical links for future High-Energy Physics experiments will require components qualified for use in radiation-hard environments. To cope with radiation induced single-event upsets, the physical layer protocol will include Forward Error Correction (FEC). Bit-Error-Rate (BER) testing is a widely used method to characterize digital transmission systems. In order to measure the BER with and without the proposed FEC, simultaneously on several devices, a multi-channel BER tester has been developed. This paper describes the architecture of the tester, its implementation in a Xilinx Virtex-5 FPGA device and discusses the experimental results.

Microstructure and hardness investigation of 17-4PH stainless steel by laser quenching

Energy Technology Data Exchange (ETDEWEB)

Chen Zhaoyun, E-mail: zhaoyunchenlaoshi@126.com [College of Materials Science and Chemical Engineering, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Nantong ST 145, Harbin 150001 (China); Zhou Guijuan, E-mail: zgjghpx@126.com [College of Materials Science and Chemical Engineering, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Nantong ST 145, Harbin 150001 (China); Chen Zhonghua, E-mail: jickdahua@163.com [College of Materials Science and Chemical Engineering, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Nantong ST 145, Harbin 150001 (China)

2012-02-01

Highlights: Black-Right-Pointing-Pointer Surface hardening of 17-4PH is highly achieved by laser transformation hardening. Black-Right-Pointing-Pointer A hardened layer with a thickness of 1.75 mm is formed. Black-Right-Pointing-Pointer The phase similar to {epsilon}-Cu precipitates re-segregation after dissolved. Black-Right-Pointing-Pointer The strengthening phase is composed of classic lath martensite, coarse NbC and a lot of finer fcc copper-rich phases. - Abstract: Surface hardening of 17-4PH was achieved by laser transformation hardening using 5 kW continuous wave CO{sub 2} laser system. The microstructure of the laser-quenched sample was investigated by optical microscopy, transmission electron microscope and {sup 57}Fe Moessbauer spectrometer. The hardness profile was determined by a Vickers hardness tester. The hardened layer with a thickness of 1.75 mm was formed, and it was composed of classic lath martensite, coarse NbC and a lot of finer fcc copper-rich phases which were similar to {epsilon}-Cu precipitates. The maximal hardness value of hardened zone is 446 HV which is 50 HV higher than that of the substrate (386-397 HV). The higher hardness in laser transformation layer of the 17-4PH steel could be attributed to the following aspects: the matrix with a high dislocation density; the fine microstructure; the finer fcc copper-rich phases that were similar to the {epsilon}-Cu precipitates as well as the transforming of retained austenite into lath martensite.

Preparation and Properties of Ti-TiN-Zr-ZrN Multilayer Films on Titanium Alloy Surface

Directory of Open Access Journals (Sweden)

LIN Song-sheng

2017-06-01

Full Text Available 24 cycles Ti-TiN-Zr-ZrN soft-hard alternating multilayer film was deposited on TC11 titanium alloy by vacuum cathodic arc deposition method. The structure and performance of the multilayer film, especially wear and sand erosion resistance were investigated by various analytical methods including pin on disc wear tester, sand erosion tester, 3D surface topography instrument, scanning electron microscopy (SEM, X-ray diffraction(XRD, micro-hardness tester and scratch adhesion tester. The results indicate that the Vickers-hardness of the multilayer film with thickness of 5.8μm can reach up to 28.10GPa. The adhesive strength of these coatings can be as high as 56N. Wear rate of the multilayer coated alloy is one order of magnitude smaller than bare one, which decreased from 7.06×10-13 m3·N-1·m-1 to 3.03×10-14m3·N-1·m-1. Multilayer films can play the role in hindering the extension of cracks, and thus sand erosion properties of the TC11 titanium alloy substrates are improved.

Composite coating containing WC/12Co cermet and Fe-based metallic glass deposited by high-velocity oxygen fuel spraying

International Nuclear Information System (INIS)

Terajima, Takeshi; Takeuchi, Fumiya; Nakata, Kazuhiro; Adachi, Shinichiro; Nakashima, Koji; Igarashi, Takanori

2010-01-01

A composite coating containing WC/12Co cermet and Fe 43 Cr 16 Mo 16 C 15 B 10 metallic glass was successfully deposited onto type 304 stainless steel by high-velocity oxygen fuel (HVOF) spraying, and the microstructure and tribological properties were investigated. The microstructure of the coating was characterized by scanning electron microscopy/electron probe micro-analysis (SEM/EPMA) and X-ray diffractometry (XRD). The hardness, adhesion strength and tribological properties of the coating were tested with a Vickers hardness tester, tensile tester and reciprocating wear tester, respectively. The composite coating, in which flattened WC/12Co was embedded in amorphous Fe 43 Cr 16 Mo 16 C 15 B 10 layers, exhibited high hardness, good wear resistance and a low friction coefficient compared to the monolithic coating. The addition of 8% WC/12Co to the Fe 43 Cr 16 Mo 16 C 15 B 10 matrix increased the cross-sectional hardness from 660 to 870 HV and reduced the friction coefficient from 0.65 to 0.5. WC/12Co reinforcement plays an important role in improving the tribological properties of the Fe 43 Cr 16 Mo 16 C 15 B 10 coating.

Poppet valve tester

Science.gov (United States)

Tellier, G. F.

1973-01-01

Tester investigates fundamental factors affecting cyclic life and sealing performance of valve seats and poppets. Tester provides for varying impact loading of poppet against seat and rate of cycling, and controls amount and type of relative motion between sealing faces of seat and poppet. Relative motion between seat and poppet can be varied in three modes.

Tester-assisted built in test

Science.gov (United States)

Guntheroth, Kurt

It is noted that board makers invest considerable time and money writing extensive self-tests and that this investment can be multiplied by selecting ATE (automatic test equipment) that complements and extends the power of the self-test. The tester can diagnose boards in situations where a fault prevents the self-test from running. If the tester monitors such resources as processor, memory, and I/O, confidence in test results is improved. The tester can be used during development of the self-test and to turn on prototypes before the self-test is complete. The author argues that emulative functional testers outperform other types of ATE on boards with BIST (built-in self-test) and lists features of emulative functional testers that are most important to users of BIST.

A comparison of damage profiling of automated tap testers on aircraft CFRP panel

Science.gov (United States)

Mohd Aris, K. D.; Shariff, M. F.; Abd Latif, B. R.; Mohd Haris, M. Y.; Baidzawi, I. J.

2017-12-01

The use of composite materials nevertheless is getting more prominent. The combination of reinforcing fibers and matrices will produce the desired strength orientation, tailorability and not to mention the complex shape that is hard to form on metallic structure. The weight percentage of composite materials used in aerospace, civil, marine etc. has increased tremendously. Since composite are stacked together, the possibility of delamination and/disbond defects are highly present either in the monolithic or sandwich structures. Tap test is the cheapest form of nondestructive test to identify the presence of this damage. However, its inconsistency and wide area of coverage can reduce its effectivity since it is carried out manually. The indigenous automated tap tester known as KETOK was used to detect the damage due to trapped voids and air pockets. The mechanism of detection is through controlling the tapping on the surface automatically at a constant rate. Another manual tap tester RD-3 from Wichitech Industries Inc. was used as reference. The acquired data was translated into damage profiling and both results were compared. The results have shown that the indigenous automated tester can profile the damage better when compared with the existing tap tester. As a conclusion, the indigenous automated tap tester has a potential to be used as an IN-SITU damage detection tool to detect delamination and disbond damage on composite panel. However, more conclusive tests need to be done in order to make the unit available to conventional users.

Evaluating microhardness of plasma sprayed Al2O3 coatings using Vickers indentation technique

International Nuclear Information System (INIS)

Yin Zhijian; Tao Shunyan; Zhou Xiaming; Ding Chuanxian

2007-01-01

In this work, the microhardness of plasma sprayed Al 2 O 3 coatings was evaluated using the Vickers indentation technique, and the effects of measurement direction, location and applied loads were investigated. The measured data sets were then statistically analysed employing the Weibull distribution to evaluate their variability within the coatings. It was found that the Vickers hardness (VHN) increases with decreasing applied indenter load, which can be explained in terms of Kick's law and the Meyer index k of 1.93, as well as relating to the microstructural characteristics of plasma sprayed coatings and the elastic recovery taking place during indentation. In addition, VHN, measured on the cross section of coatings, was obviously higher than that on its top surface. The obtained Weibull modulus and variation coefficient indicate that the VHN was less variable when measured at a higher applied load and on the cross section of coating. The obvious dependence of the VHN on the specific indentation location within through-thickness direction was also realized. These phenomena described above in this work were related to the special microstructure and high anisotropic behaviour of plasma sprayed coatings

Hardness of basaltic glass-ceramics

DEFF Research Database (Denmark)

Jensen, Martin; Smedskjær, Morten Mattrup; Estrup, Maja

2009-01-01

The dependence of the hardness of basaltic glass-ceramics on their degree of crystallisation has been explored by means of differential scanning calorimetry, optical microscopy, x-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses were achieved...... by varying the temperature of heat treatment. The predominant crystalline phase in the glass was identified as augite. It was found that the hardness of the glass phase decreased slightly with an increase in the degree of crystallisation, while that of the augite phase drastically decreased....

UW VLSI chip tester

Science.gov (United States)

McKenzie, Neil

1989-12-01

We present a design for a low-cost, functional VLSI chip tester. It is based on the Apple MacIntosh II personal computer. It tests chips that have up to 128 pins. All pin drivers of the tester are bidirectional; each pin is programmed independently as an input or an output. The tester can test both static and dynamic chips. Rudimentary speed testing is provided. Chips are tested by executing C programs written by the user. A software library is provided for program development. Tests run under both the Mac Operating System and A/UX. The design is implemented using Xilinx Logic Cell Arrays. Price/performance tradeoffs are discussed.

Spring performance tester for miniature extension springs

Science.gov (United States)

Salzbrenner, Bradley; Boyce, Brad

2017-05-16

A spring performance tester and method of testing a spring are disclosed that has improved accuracy and precision over prior art spring testers. The tester can perform static and cyclic testing. The spring tester can provide validation for product acceptance as well as test for cyclic degradation of springs, such as the change in the spring rate and fatigue failure.

The influence of material hardness on liquid droplet impingement erosion

International Nuclear Information System (INIS)

Fujisawa, Nobuyuki; Yamagata, Takayuki; Takano, Shotaro; Saito, Kengo; Morita, Ryo; Fujiwara, Kazutoshi; Inada, Fumio

2015-01-01

Highlights: • Liquid droplet impingement erosion is studied for various metal materials. • Average power dependency on droplet velocity is found as 7. • Power dependency on Vickers hardness is found as −4.5. • An empirical formula is constructed for erosion rates of metal materials. • Predicted erosion rate is well correlated with experiment within a factor of 1.5. - Abstract: This paper describes the experimental study on the liquid droplet impingement erosion of metal materials to understand the influence of material hardness on the erosion rate. The experiment is carried out using a water spray jet apparatus with a condition of relatively thin liquid film thickness. The metal materials tested are pure aluminum, aluminum alloy, brass, mild steel, carbon steel and stainless steel. The liquid droplets considered are 30 ± 5 μm in volume average diameter of water, which is the same order of droplet diameter in the actual pipeline in nuclear/fossil power plants. In order to understand the influence of material hardness on the liquid droplet impingement erosion, the scanning electron microscope (SEM) observation on the eroded surface and the measurement of erosion rate are carried out in the terminal stage of erosion. The experimental results indicate that the erosion rates are expressed by the droplet velocity, volume flux, Vickers hardness and the liquid film thickness, which are fundamentals of the liquid droplet impingement erosion. The empirical formula shows that the power index for droplet velocity dependency is found to be 7 with a scattering from 5 to 9 depending on the materials, while the power index for Vickers hardness dependency is found as −4.5

The influence of material hardness on liquid droplet impingement erosion

Energy Technology Data Exchange (ETDEWEB)

Fujisawa, Nobuyuki, E-mail: fujisawa@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Yamagata, Takayuki, E-mail: yamagata@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Takano, Shotaro; Saito, Kengo [Graduate School of Science and Technology, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Morita, Ryo; Fujiwara, Kazutoshi; Inada, Fumio [Central Research Institute of Electric Power Industry, 2-11-1, Iwatokita, Komae, Tokyo 201-8511 (Japan)

2015-07-15

Highlights: • Liquid droplet impingement erosion is studied for various metal materials. • Average power dependency on droplet velocity is found as 7. • Power dependency on Vickers hardness is found as −4.5. • An empirical formula is constructed for erosion rates of metal materials. • Predicted erosion rate is well correlated with experiment within a factor of 1.5. - Abstract: This paper describes the experimental study on the liquid droplet impingement erosion of metal materials to understand the influence of material hardness on the erosion rate. The experiment is carried out using a water spray jet apparatus with a condition of relatively thin liquid film thickness. The metal materials tested are pure aluminum, aluminum alloy, brass, mild steel, carbon steel and stainless steel. The liquid droplets considered are 30 ± 5 μm in volume average diameter of water, which is the same order of droplet diameter in the actual pipeline in nuclear/fossil power plants. In order to understand the influence of material hardness on the liquid droplet impingement erosion, the scanning electron microscope (SEM) observation on the eroded surface and the measurement of erosion rate are carried out in the terminal stage of erosion. The experimental results indicate that the erosion rates are expressed by the droplet velocity, volume flux, Vickers hardness and the liquid film thickness, which are fundamentals of the liquid droplet impingement erosion. The empirical formula shows that the power index for droplet velocity dependency is found to be 7 with a scattering from 5 to 9 depending on the materials, while the power index for Vickers hardness dependency is found as −4.5.

Degree of conversion and surface hardness of resin cement cured with different curing units.

Science.gov (United States)

Ozturk, Nilgun; Usumez, Aslihan; Usumez, Serdar; Ozturk, Bora

2005-01-01

The aim of this study was to evaluate the degree of conversion and Vickers surface hardness of resin cement under a simulated ceramic restoration with 3 different curing units: a conventional halogen unit, a high-intensity halogen unit, and a light-emitting diode system. A conventional halogen curing unit (Hilux 550) (40 s), a high-intensity halogen curing unit used in conventional and ramp mode (Optilux 501) (10 s and 20 s, respectively), and a light-emitting diode system (Elipar FreeLight) (20 s, 40 s) were used in this study. The dual-curing resin cement (Variolink II) was cured under a simulated ceramic restoration (diameter 5 mm, height 2 mm), and the degree of conversion and Vickers surface hardness were measured. For degree of conversion measurement, 10 specimens were prepared for each group. The absorbance peaks were recorded using the diffuse-reflection mode of Fourier transformation infrared spectroscopy. For Vickers surface hardness measurement, 10 specimens were prepared for each group. A load of 200 N was applied for 15 seconds, and 3 evaluations of each of the samples were performed. Degree of conversion achieved with Optilux 501 (20 s) was significantly higher than those of Hilux, Optilux 501 (10 s), Elipar FreeLight (20 s), and Elipar FreeLight (40 s). For Vickers surface hardness measurement, Optilux 501 (20 s) produced the highest surface hardness value. No significant differences were found among the Hilux, Optilux 501 (10 s), Elipar FreeLight (20 s), and Elipar FreeLight (40 s). The high-intensity halogen curing unit used in ramp mode (20 s) produced harder resin cement surfaces than did the conventional halogen curing unit, high-intensity halogen curing unit used in conventional mode (10 s) and light-emitting diode system (20 s, 40 s), when cured through a simulated ceramic restoration.

Common tester platform concept.

Energy Technology Data Exchange (ETDEWEB)

Hurst, Michael James

2008-05-01

This report summarizes the results of a case study on the doctrine of a common tester platform, a concept of a standardized platform that can be applicable across the broad spectrum of testing requirements throughout the various stages of a weapons program, as well as across the various weapons programs. The common tester concept strives to define an affordable, next-generation design that will meet testing requirements with the flexibility to grow and expand; supporting the initial development stages of a weapons program through to the final production and surveillance stages. This report discusses a concept investing key leveraging technologies and operational concepts combined with prototype tester-development experiences and practical lessons learned gleaned from past weapons programs.

Evaluation of Polymerization Efficacy in Composite Resins via FT-IR Spectroscopy and Vickers Microhardness Test

Directory of Open Access Journals (Sweden)

Tahereh-Sadat Jafarzadeh

2015-12-01

Full Text Available Background and aims. Polymerization efficacy affects the properties and performance of composite resin restorations.The purpose of this study was to evaluate the effectiveness of polymerization of two micro-hybrid, two nano-hybrid and one nano-filled ormocer-based composite resins, cured by two different light-curing systems, using Fourier transformation infrared (FT-IR spectroscopy and Vickers microhardness testing at two different depths (top surface, 2 mm. Materials and methods. For FT-IR spectrometry, five cylindrical specimens (5mm in diameter × 2 mm in length were prepared from each composite resin using Teflon molds and polymerized for 20 seconds. Then, 70-μm wafers were sectioned at the top surface and at2mm from the top surface. The degree of conversion for each sample was calculated using FT-IR spectroscopy. For Vickers micro-hardness testing, three cylindrical specimens were prepared from each composite resin and polymerized for 20 seconds. The Vickers microhardness test (Shimadzu, Type M, Japan was performed at the top and bottom (depth=2 mm surfaces of each specimen. Three-way ANOVA with independent variables and Tukey tests were performed at 95% significance level. Results. No significant differences were detected in degree of conversion and microhardness between LED and QTH light-curing units except for the ormocer-based specimen, CeramX, which exhibited significantly higher DC by LED. All the composite resins showed a significantly higher degree of conversion at the surface. Microhardness was not significantly affected by depth, except for Herculite XRV Ultra and CeramX, which showed higher values at the surface. Conclusion. Composite resins containing nano-particles generally exhibited more variations in degree of conversion and microhardness.

Evaluation of Polymerization Efficacy in Composite Resins via FT-IR Spectroscopy and Vickers Microhardness Test.

Science.gov (United States)

Jafarzadeh, Tahereh-Sadat; Erfan, Mohammad; Behroozibakhsh, Marjan; Fatemi, Mostafa; Masaeli, Reza; Rezaei, Yashar; Bagheri, Hossein; Erfan, Yasaman

2015-01-01

Background and aims. Polymerization efficacy affects the properties and performance of composite resin restorations.The purpose of this study was to evaluate the effectiveness of polymerization of two micro-hybrid, two nano-hybrid and one nano-filled ormocer-based composite resins, cured by two different light-curing systems, using Fourier transformation infrared (FT-IR) spectroscopy and Vickers microhardness testing at two different depths (top surface, 2 mm). Materials and methods. For FT-IR spectrometry, five cylindrical specimens (5mm in diameter × 2 mm in length) were prepared from each composite resin using Teflon molds and polymerized for 20 seconds. Then, 70-μm wafers were sectioned at the top surface and at2mm from the top surface. The degree of conversion for each sample was calculated using FT-IR spectroscopy. For Vickers micro-hardness testing, three cylindrical specimens were prepared from each composite resin and polymerized for 20 seconds. The Vickers microhardness test (Shimadzu, Type M, Japan) was performed at the top and bottom (depth=2 mm) surfaces of each specimen. Three-way ANOVA with independent variables and Tukey tests were performed at 95% significance level. Results. No significant differences were detected in degree of conversion and microhardness between LED and QTH light-curing units except for the ormocer-based specimen, CeramX, which exhibited significantly higher DC by LED. All the composite resins showed a significantly higher degree of conversion at the surface. Microhardness was not significantly affected by depth, except for Herculite XRV Ultra and CeramX, which showed higher values at the surface. Conclusion. Composite resins containing nano-particles generally exhibited more variations in degree of conversion and microhardness.

Influence of 1,3,6 naphthalene trisulfonic acid on microstructure & hardness in electrodeposited Ni-layers

DEFF Research Database (Denmark)

Rasmussen, Anette Alsted; Møller, Per; Somers, Marcel A. J.

2002-01-01

The influence of the additive 1,3,6 naphthalene trisulfonic acid on the microstructure and hardness of electrodeposited nickel layers was investigated. The microstructure was characterized using transmission electron microscopy; the Vickers hardness was measured in cross sections. The additive wa...

Novel platens to measure the hardness of a pentagonal shaped tablet.

Science.gov (United States)

Malladi, Jaya; Sidik, Kurex; Wu, Sutan; McCann, Ryan; Dougherty, Jeffrey; Parab, Prakash; Carragher, Thomas

2017-03-01

Tablet hardness, a measure of the breaking force of a tablet, is based on numerous factors. These include the shape of the tablet and the mode of the application of force. For instance, when a pentagonal-shaped tablet was tested with a traditional hardness tester with flat platens, there was a large variation in hardness measurements. This was due to the propensity of vertices of the tablet to crush, referred to as an "improper break". This article describes a novel approach to measure the hardness of pentagonal-shaped tablets using modified platens. The modified platens have more uniform loading than flat platens. This is because they reduce loading on the vertex of the pentagon and apply forces on tablet edges to generate reproducible tablet fracture. The robustness of modified platens was assessed using a series of studies, which included feasibility and Gauge Repeatability & Reproducibility (R&R) studies. A key finding was that improper breaks, generated frequently with a traditional hardness tester using flat platens, were eliminated. The Gauge R&R study revealed that the tablets tested with novel platens generated consistent values in hardness measurements, independent of batch, hardness level, and day of testing, operator and tablet dosage strength.

Research on characteristics measurement of infrared defect tester

Science.gov (United States)

Zhang, Ke-jia; Zhang, Bi-feng; Xiong, Li-min; Zhou, Tao-geng; Zhang, Jun-chao; Meng, Hai-feng; Cai, Chuan; He, Ying-wei; Li, Xiao-hui; Wang, Chang-shi

2017-10-01

Based on a testing method of spatial frequency response(SFR), a setup for characteristics measurements of the infrared defect tester,which can also be called electroluminescence tester(EL tester), a machine examining defects of photovoltaic (PV) panel, was built. The influences of focusing plane adjustments and infrared light box arrangements on resolution measurement of EL tester in full field of view were analyzed. For different types of EL testers, portable and fixed, testing methods and procedures were presented. Especially, a novel testing method for portable EL was claimed, which could do the work well without reference background. Based on method claimed and setup built, the resolutions of different types of EL testers were obtained and stable results were achieved. This setup is portable designed to meet online measurements requirements of PV industry.

Mechanical properties of titanium-hydroxyapatite (Ti-HA) composite coating on stainless steel prepared by thermal spraying

Science.gov (United States)

Rosmamuhamadani, R.; Azhar, N. H.; Talari, M. K.; Yahaya, Sabrina M.; Sulaiman, S.; Ismail, M. I. S.

2017-09-01

Addition of hydroxyapatite (HA) can enhance the bioactivity of the common metallic implant due to its similarity with natural bones and teeth. In this investigation, high velocity oxy-fuel (HVOFT) technique was used to deposit titanium-hydroxyapatite (Ti-HA) composite on stainless steel substrate plate with different percentage of HA for biomedical applications. The aim of this research is to investigate the mechanical properties of Ti-HA coating such as hardness, adhesion strength and wear behaviour. The hardness and strength was determined by using SHIMADZU-microhardness Vickers tester and PosiTest AT portable adhesion tester respectively. The wear test was performed by using pin-on-disk equipment and field emission scanning electron microscope (FESEM) used to determine the extent of surface damage. From the results obtained, mechanical properties such as hardness and adhesion strength of titanium (Ti) coating decreased with the increased of HA contents. Meanwhile, the coefficient of friction of Ti-10% HA coating shows the highest value compare to others as three-body abrasion had occurred during the test.

Cathodoluminescence study of vickers indentations in magnesium ...

African Journals Online (AJOL)

Vickers diamond pyramid indentations made in single crystal of magnesium oxide (MgO) were examined in an environmental scanning electron microscope interfaced with an AVS-2000 spectrophotometer for luminescence. Three distinct zones around the indentations were identified to exhibit cathodoluminescence, which ...

Development of a second generation rolling contact fatigue tester

Science.gov (United States)

Deshmukh, Satyam U.

Contact fatigue failure has been in research since the early twentieth century. The need for a second generation sliding-rolling contact fatigue tester was proposed by Gregory Dvorak and Dr. Marcellin Zahui. The first generation RCF tester was used for testing super finishing processes for gear surfaces. The second generation RCF tester was funded by the Advanced Engineering Materials lab of University of North Dakota. Verification of the second generation Rolling Contact Fatigue Tester will be discussed in this thesis including the design details, assembly and testing procedure and to discuss its different parameters. The tester will have the capability of testing hollow specimens using a bobbin eddy current testing probe. This tester will allow a wide range of experiments and is not built for one specific purpose. An eddy current device is used for detecting cracks. The loading force is applied using hydraulic cylinders and a hydraulic power unit. Before testing began, the machine was run for some time at full speed. A lot of minor problems were detected and fixed. Three specimens of AISI 8620 were tested in this tester. All tests gave results matching with some of the other well-known RCF testers. These tests were performed to evaluate mechanical limits of the tester and to evaluate the software performance of the tester.

Role of elastic deformation in determining the mixed alkaline earth effect of hardness in silicate glasses

DEFF Research Database (Denmark)

Kjeldsen, Jonas; Smedskjær, Morten Mattrup; Potuzak, M.

2015-01-01

been investigated previously, but the link between the resistance to elastic deformation and hardness has not yet been studied. In this work, we investigate the link between elastic deformation during indentation and Vickers hardness in a series of mixed magnesium-barium boroaluminosilicate glasses. We...

Advanced TCA Backplane Tester

CERN Document Server

Oltean, Alexandra Dana

2004-01-01

At the beginning of 2003, the PICMG group adopted the AdvancedTCA (Advanced Telecom Computing Architecture) standard. The 10Gb/s backplane of the AdvancedTCA chassis is well specified in the standard but it remains however a high end product, which can be itself subject to printed circuit board manufacturing control problems that could greatly affect its quality control. In order to study the practical aspects of high speed Ethernet switching at 10Gb/s and to validate the signal integrity of the AdvancedTCA backplane, we developed a Backplane Tester. The tester system is able of running monitored PRBS traffic at 3.125Gb/s over every link on the AdvancedTCA backplane simultaneously and to monitor any possible connectivity failure immediately in terms of link and slot position inside the chassis. The present report presents the architectural hardware design, the control structure and software aspects of the AdvancedTCA Backplane Tester design.

21 CFR 870.3720 - Pacemaker electrode function tester.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker electrode function tester. 870.3720... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which is...

Two ankle joint laxity testers: reliability and validity

NARCIS (Netherlands)

Kerkhoffs, Gino M. M. J.; Blankevoort, Leendert; Sierevelt, Inger N.; Corvelein, Ruby; Janssen, Guido H. W.; van Dijk, C. Niek

2005-01-01

Two test devices were manufactured to objectively measure ankle joint laxity: the dynamic anterior ankle tester (DAAT) and the quasi-static anterior ankle tester (QAAT). The primary aim was to analyse the reliability of both testers; The secondary aim was to assess validity in correlation with TELOS

The relationship between vickers microhardness and compressive strength of functional surface geopolymers

Science.gov (United States)

Subaer, Ekaputri, Januari Jaya; Fansuri, Hamzah; Abdullah, Mustafa Al Bakri

2017-09-01

An experimental study to investigate the relationship between Vickers microhardness and compressive strength of geopolymers made from metakaolin has been conducted. Samples were prepared by using metakaolin activated with a sodium silicate solution at a different ratio of Si to Al and Na to Al and cured at 70oC for one hour. The resulting geopolymers were stored in an open air for 28 days before conducting any measurement. Bulk density and apparent porosity of the samples were measured by using Archimedes's method. Vickers microhardness measurements were performed on a polished surface of geopolymers with a load ranging from 0.3 - 1.0 kg. The topographic of indented samples were examined by using scanning electron microscopy (SEM). Compressive strength of the resulting geopolymers was measured on the cylindrical samples with a ratio of height to the diameter was 2:1. The results showed that the molar ratios of geopolymers compositions play important roles in the magnitude of bulk density, porosity, Vickers's microhardness as well as the compressive strength. The porosity reduced exponentially the magnitude of the strength of geopolymers. It was found that the relationship between Vickers microhardness and compressive strength was linear. At the request of all authors and with the approval of the proceedings editor, article 020188 titled, "The relationship between vickers microhardness and compressive strength of functional surface geopolymers," is being retracted from the public record due to the fact that it is a duplication of article 020170 published in the same volume.

Evaluation and Comparison of the Effects of RRA, T73 and T6 Heat Treatments on Hardness, Tensile and Bending Strengths of 7075 Aluminum Alloy

Directory of Open Access Journals (Sweden)

M. Assadi

2016-09-01

20 min and in the third stage aging process was repeated like T6 treatment. Evaluation of the microstructures and fractured surfaces were performed with optical microscopes (OM and scanning electron microscopes (SEM. Energy dispersive spectroscopy (EDS was used to study the chemical composition of precipitates. Hardness, tensile and bending strength were evaluated according to ASTM E384-11e1, ASTM B557-06 and DIN 50121 standards. RRA treatment increased tensile strength from 466 to 485 MPa and hardness from 110 to 165 Vickers. After T6 treatment, tensile strength increased from 466 to 505 MPa and hardness from 110 to 160 Vickers. In T73 process, the tensile strength remained almost constant (465 MPa but yield strength increased from 394 to 410 MPa and hardness decreased from 110 to 84 Vickers. The bending strength increased from 797 to 844, 920 and 1030 MPa in T73, RRA and T6 processes, respectively. By applying RRA process in optimized temperature and time, hardness, tensile and bending strengths of 7075 aluminum alloy were enhanced from 5 to 15% compared to that of T6 and T73 processes.

Hardness of ion implanted ceramics

International Nuclear Information System (INIS)

Oliver, W.C.; McHargue, C.J.; Farlow, G.C.; White, C.W.

1985-01-01

It has been established that the wear behavior of ceramic materials can be modified through ion implantation. Studies have been done to characterize the effect of implantation on the structure and composition of ceramic surfaces. To understand how these changes affect the wear properties of the ceramic, other mechanical properties must be measured. To accomplish this, a commercially available ultra low load hardness tester has been used to characterize Al 2 O 3 with different implanted species and doses. The hardness of the base material is compared with the highly damaged crystalline state as well as the amorphous material

The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian)

OpenAIRE

Daniela Ogrean

2001-01-01

The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes) indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Tim...

Crystallographic Analysis of Nucleation at Hardness Indentations in High-Purity Aluminum

DEFF Research Database (Denmark)

Xu, Chaoling; Zhang, Yubin; Lin, Fengxiang

2016-01-01

Nucleation at Vickers hardness indentations has been studied in high-purity aluminum cold-rolled 12 pct. Electron channeling contrast was used to measure the size of the indentations and to detect nuclei, while electron backscattering diffraction was used to determine crystallographic orientations....... It is found that indentations are preferential nucleation sites. The crystallographic orientations of the deformed grains affect the hardness and the nucleation potentials at the indentations. Higher hardness gives increased nucleation probabilities. Orientation relationships between nuclei developed...... they form. Finally, possible nucleation mechanisms are briefly discussed....

The comparison of the effects of different whitening toothpastes on the micro hardness of a nano hybrid composite resin.

Science.gov (United States)

Nainan, Mohan Thomas; Balan, Ashok Kalappurakkal; Sharma, Roshni; Thomas, Sabeena Susan; Deveerappa, Santhosh B

2014-11-01

The aim of this study was to compare the micro hardness of a nanohybrid composite resin after brushing with two herbal and one non-herbal whitening toothpastes. We divided Eighty disk-shaped specimens of a nanohybrid composite (Tetric N Ceram, Ivoclar Vivadent, Asia) into 4 groups of 20 specimens each: Groups A, B, C, and D. Group A was control, Group B was brushed with Colgate total advanced whitening (Colgate-Palmolive (India) Limited), Group C with Salt and Lemon, Dabur (Dabur International Limited, Dubai, UAE), and Group D with HiOra Shine, Himalaya (The Himalaya Drug Company, India). The specimens were polished using medium, fine, and superfine discs (Sof-lex, 3M, ESPE, USA) and subsequently placed at 37°C in distilled water. They were brushed for 2 minutes twice daily with a soft motorized toothbrush (Colgate 360 sonic power battery-operated tooth brush, Colgate Palmolive, India) for 30 days. The samples were rinsed under running water to remove the toothpaste and stored in distilled water at 37°C until the readout was taken on the Vickers's hardness tester for microhardness. The results revealed that the difference among the groups was statistically significant (P < 0.001). Tukey's test showed that reduction in microhardness for Group B was significantly higher than that for Group C and Group D (P < 0.001). Within the limitations of this study, non-herbal whitening toothpaste had a greater impact on the microhardness of nanohybrid resin composite than herbal whitening toothpastes.

Hydrogen fracture toughness tester completion

Energy Technology Data Exchange (ETDEWEB)

Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-09-30

The Hydrogen Fracture Toughness Tester (HFTT) is a mechanical testing machine designed for conducting fracture mechanics tests on materials in high-pressure hydrogen gas. The tester is needed for evaluating the effects of hydrogen on the cracking properties of tritium reservoir materials. It consists of an Instron Model 8862 Electromechanical Test Frame; an Autoclave Engineering Pressure Vessel, an Electric Potential Drop Crack Length Measurement System, associated computer control and data acquisition systems, and a high-pressure hydrogen gas manifold and handling system.

Microcontroller based Integrated Circuit Tester

OpenAIRE

Yousif Taha Yousif Elamin; Abdelrasoul Jabar Alzubaidi

2015-01-01

The digital integrated circuit (IC) tester is implemented by using the ATmega32 microcontroller . The microcontroller processes the inputs and outputs and displays the results on a Liquid Crystal Display (LCD). The basic function of the digital IC tester is to test a digital IC for correct logical functioning as described in the truth table and/or function table. The designed model can test digital ICs having 14 pins. Since it is programmable, any number of ICs can be tested . Thi...

Correlation between Fe–V–C alloys surface hardness and plasma temperature via LIBS technique

Energy Technology Data Exchange (ETDEWEB)

Messaoud Aberkane, S., E-mail: smessaoud@cdta.dz [Centre de Développement des Technologies Avancées, Baba Hassen, Alger (Algeria); Bendib, A. [Université des Sciences et de Technologie Houari Boumediene, Bab-Ezzouar, Alger (Algeria); Yahiaoui, K.; Boudjemai, S.; Abdelli-Messaci, S.; Kerdja, T. [Centre de Développement des Technologies Avancées, Baba Hassen, Alger (Algeria); Amara, S.E. [Université des Sciences et de Technologie Houari Boumediene, Bab-Ezzouar, Alger (Algeria); Harith, M.A. [National Institute of Laser Enhanced Science, Cairo University (Egypt)

2014-05-01

Highlights: • New application of LIBS in industry. • Hardness of metallic alloys estimation using LIBS calibration curves. • Linear correlation between the plasma temperature and the hardness of metallic alloys. • The shock wave is fast when the material is hard. - Abstract: Surface hardness is a very important characteristic of metals. Its monitoring plays a key role in industry. In the present paper, using laser induced breakdown spectroscopy (LIBS), Fe–V{sub 18%}–C{sub 1%} alloys with different heat treatments have been used for making the correlation between surface hardness and laser-induced plasma temperatures. All investigated samples were characterized by the same ferrite phase with different Vickers surface hardnesses. The differences in hardness values were attributed to the crystallite size changes. A linear relationship has been obtained between the Vickers surface hardness and the laser induced plasma temperature. For comparison the relation between surface hardness and the ratio of the vanadium ionic to atomic spectral lines intensities (VII/VI) provided good linear results too. However, adopting the proposed approach of using the plasma temperature, instead, is more reliable in view of the difficulties that could be encountered in choosing the proper ionic and atomic spectral lines. To validate this approach we have investigated the shock wave speed induced by laser interaction with the used samples. It was found that harder is the material faster is the shock wave. The determination of the surface hardness via measuring T{sub e} shows the feasibility of using LIBS as an easy and reliable method for in situ industrial application for production control.

Evaluation of hot hardness, creep, fatigue and fracture properties of zirconia ceramics by an indentation technique

International Nuclear Information System (INIS)

Kutty, T.R.G.; Ganguly, C.; Upadhyaya, D.D.

1996-01-01

Zirconia ceramics have wide range engineering applications at room and elevated temperatures. For understanding the mechanical behaviour, the indentation technique was adapted for quick evaluation of hot hardness, creep, fatigue and fracture properties. A Vicker's diamond indentor with 10 N load was employed for hot hardness and creep measurement up to 1300 deg. The fatigue data were evaluated at room temperature by repeated indentation with a constant load (10-2500N) at the same location for a dwell time of 5s until it resulted in the formation of a lateral chip on the sample surface. Thus, the number of cycles for chip formation at a specific indentation load was obtained. The fracture toughness was evaluated at room temperature with a load of 300N using a Vicker's diamond indentor. The results of hot hardness, creep, fatigue, and fracture data ol 3Y-TZP and Mg-PSZ are discussed along with their microstructural features. (authors)

The effect of liquid phase separation on the Vickers microindentation shear bands evolution in a Fe-based bulk metallic glass

Energy Technology Data Exchange (ETDEWEB)

Askari-Paykani, M. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, North Kargar Street, Tehran 11356-4563 (Iran, Islamic Republic of); Nili Ahmadabadi, M., E-mail: nili@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, North Kargar Street, Tehran 11356-4563 (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Seiffodini, A. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, North Kargar Street, Tehran 11356-4563 (Iran, Islamic Republic of); Yazd University, Department of Material Science and Engineering, Yazd 84196 (Iran, Islamic Republic of)

2013-11-15

The Vickers microindentation experiments and associated plastic deformation in as-cast and annealed (Fe{sub 0.9}Ni{sub 0.1}){sub 77}Mo{sub 5}P{sub 9}C{sub 7.5}B{sub 1.5} bulk metallic glass was conducted. In addition to the bulk indentation behavior, the shear band morphology underneath the Vickers microindenter was examined by employing the bonded interface technique. Microstructural characterization revealed that a liquid phase separation occurred during melting process. Atomic force microscopy of the glassy matrix of the as-cast specimen reveals the composition inhomogeneity induced by the liquid phase separation. This effect generates shear band branching or deflection during the shear band propagation. For the bulk indentation, the trends in the hardness vs. indentation load were found related to the pressure sensitive index and the phase separation process simultaneously. The results show that the as-cast as well as the annealed specimens are deformed through semi-circular and radial shear bands. In addition, in the partially crystalized specimen, the change in the properties and microstructure of the BMG induced by the partial crystallization treatment and phase separation process resulted in tertiary shear bands formation.

Open-source micro-tensile testers via additive manufacturing for the mechanical characterization of thin films and papers.

Directory of Open Access Journals (Sweden)

Krishanu Nandy

Full Text Available The cost of specialized scientific equipment can be high and with limited funding resources, researchers and students are often unable to access or purchase the ideal equipment for their projects. In the fields of materials science and mechanical engineering, fundamental equipment such as tensile testing devices can cost tens to hundreds of thousands of dollars. While a research lab often has access to a large-scale testing machine suitable for conventional samples, loading devices for meso- and micro-scale samples for in-situ testing with the myriad of microscopy tools are often hard to source and cost prohibitive. Open-source software has allowed for great strides in the reduction of costs associated with software development and open-source hardware and additive manufacturing have the potential to similarly reduce the costs of scientific equipment and increase the accessibility of scientific research. To investigate the feasibility of open-source hardware, a micro-tensile tester was designed with a freely accessible computer-aided design package and manufactured with a desktop 3D-printer and off-the-shelf components. To our knowledge this is one of the first demonstrations of a tensile tester with additively manufactured components for scientific research. The capabilities of the tensile tester were demonstrated by investigating the mechanical properties of Graphene Oxide (GO paper and thin films. A 3D printed tensile tester was successfully used in conjunction with an atomic force microscope to provide one of the first quantitative measurements of GO thin film buckling under compression. The tensile tester was also used in conjunction with an atomic force microscope to observe the change in surface topology of a GO paper in response to increasing tensile strain. No significant change in surface topology was observed in contrast to prior hypotheses from the literature. Based on this result obtained with the new open source tensile stage we

Open-source micro-tensile testers via additive manufacturing for the mechanical characterization of thin films and papers.

Science.gov (United States)

Nandy, Krishanu; Collinson, David W; Scheftic, Charlie M; Brinson, L Catherine

2018-01-01

The cost of specialized scientific equipment can be high and with limited funding resources, researchers and students are often unable to access or purchase the ideal equipment for their projects. In the fields of materials science and mechanical engineering, fundamental equipment such as tensile testing devices can cost tens to hundreds of thousands of dollars. While a research lab often has access to a large-scale testing machine suitable for conventional samples, loading devices for meso- and micro-scale samples for in-situ testing with the myriad of microscopy tools are often hard to source and cost prohibitive. Open-source software has allowed for great strides in the reduction of costs associated with software development and open-source hardware and additive manufacturing have the potential to similarly reduce the costs of scientific equipment and increase the accessibility of scientific research. To investigate the feasibility of open-source hardware, a micro-tensile tester was designed with a freely accessible computer-aided design package and manufactured with a desktop 3D-printer and off-the-shelf components. To our knowledge this is one of the first demonstrations of a tensile tester with additively manufactured components for scientific research. The capabilities of the tensile tester were demonstrated by investigating the mechanical properties of Graphene Oxide (GO) paper and thin films. A 3D printed tensile tester was successfully used in conjunction with an atomic force microscope to provide one of the first quantitative measurements of GO thin film buckling under compression. The tensile tester was also used in conjunction with an atomic force microscope to observe the change in surface topology of a GO paper in response to increasing tensile strain. No significant change in surface topology was observed in contrast to prior hypotheses from the literature. Based on this result obtained with the new open source tensile stage we propose an

The rf-power dependences of the deposition rate, the hardness and the corrosion-resistance of the chromium nitride film deposited by using a dual ion beam sputtering system

International Nuclear Information System (INIS)

Lim, Jongmin; Lee, Chongmu

2006-01-01

The hexavalent chromium used in chromium plating is so toxic that it is very hazardous to human body and possibly causes cancer in humans. Therefore, it is indispensable to develop an alternative deposition technique. Dependences of the deposition rate, the phases, the hardness, the surface roughness and the corrosion-resistance of CrN x deposited on the high speed steel substrate by using a dual ion beam sputtering system on the rf-power were investigated to see the feasibility of sputtering as an alternative technique for chromium plating. The dual ion beam sputtering system used in this study was designed in such a way as the primary argon ion beam and the secondary nitrogen ion beam are injected toward the target and the substrate, respectively so that the chromium atoms at the chromium target surface may not nearly react with nitrogen atoms. The hardness and the surface roughness were measured by a micro-Vicker's hardness tester and an atomic force microscope (AFM), respectively. X-ray diffraction analyses were performed to identify phases in the films. The deposition rate of CrN x depends more strongly upon the rf-power for argon ion beam than that for nitrogen ion beam. The hardness of the CrN x film is highest when the volume percent of the Cr 2 N phase in the film is highest. Amorphous films are obtained when the rf-power for nitrogen ion beam is much higher than that for argon ion beam. The CrN x film deposited by using the sputtering technique under the optimal condition provides corrosion-resistance comparable to that of the electroplated chromium

7 CFR 801.4 - Tolerances for dockage testers.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Tolerances for dockage testers. 801.4 Section 801.4 Agriculture Regulations of the Department of Agriculture (Continued) GRAIN INSPECTION, PACKERS AND STOCKYARD... FOR GRAIN INSPECTION EQUIPMENT § 801.4 Tolerances for dockage testers. The maintenance tolerances for...

Applications of NTNU/SINTEF Drillability Indices in Hard Rock Tunneling

Science.gov (United States)

Zare, S.; Bruland, A.

2013-01-01

Drillability indices, i.e., the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), Cutter Life Index™ (CLI), and Vickers Hardness Number Rock (VHNR), are indirect measures of rock drillability. These indices are recognized as providing practical characterization of rock properties used in the Norwegian University of Science and Technology (NTNU) time and cost prediction models available for hard rock tunneling and surface excavation. The tests form the foundation of various hard rock equipment capacity and performance prediction methods. In this paper, application of the tests for tunnel boring machine (TBM) and drill and blast (D&B) tunneling is investigated and the impact of the indices on excavation time and costs is presented.

Effect of Crystallisation Degree on Hardness of Basaltic Glass-Ceramics

DEFF Research Database (Denmark)

Jensen, Martin; Smedskjær, Morten Mattrup; Yue, Yuanzheng

The dependence of hardness of basaltic glass-ceramics on their crystallisation degree has been explored by means of differential scanning calorimetry, optical microscopy, X-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses have been obtained...... by varying the temperature of heat treatment. The change of the relative degree of crystallisation with the heat treatment temperature can be described by an empirical model established in this work. The predominant crystalline phase in the glass has been identified as the pyroxene augite. The hardness...... principle calculations. It is found that the hardness of the glass phase decreases slightly with an increase in the degree of crystallisation, while that of the augite phase drastically decreases....

Hardness and microstructural characteristics of rapidly solidified Al-8-16 wt.%Si alloys

International Nuclear Information System (INIS)

Uzun, O.; Karaaslan, T.; Gogebakan, M.; Keskin, M.

2004-01-01

Al-Si alloys with nominal composition of Al-8 wt.%Si, Al-12 wt.%Si, and Al-16 wt.%Si were rapidly solidified by using melt-spinning technique to examine the influence of the cooling rate/conditions on microstructure and mechanical properties. The microstructures of the rapidly solidified ribbons and ingot samples were investigated by the optical microscopy, electron microscopy and X-ray diffraction (XRD) techniques. The results showed that the structures of all melt-spun ribbons were completely composed of finely dispersed α-Al and eutectic Si phase, and primary silicon was not observed. The XRD analysis indicated that the solubility of Si in the α-Al matrix was greatly increased with rapid solidification. Additionally, mechanical properties of both conventionally cast (ingot) and melt-spun ribbons were examined by using Vickers indenter for one applied load (0.098 N). The hardness values of the melt-spun ribbons were about three times higher than those of ingot counterparts. The high hardness of the rapidly solidified state can be attributed to the supersaturated solid solutions. Besides, hardness values with different applied loads were measured for melt-spun ribbons. The results indicated that Vickers hardness values (H v ) of the ribbons depended on the applied load. Applying the concept of Hays-Kendall, the load independent hardness values were calculated as 694.0, 982.8 and 1186.8 MN/m 2 for Al-8 wt.%Si, Al-12 wt.%Si and Al-16 wt.%Si, respectively

Structural and mechanical properties of ZnMgO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tosun, M. [Istanbul Technical University, Faculty of Mechanical Engineering, 34437, Gumussuyu, Istanbul (Turkey); Ataoglu, S. [Istanbul Technical University, Faculty of Civil Engineering, 34469, Maslak, Istanbul (Turkey); Istanbul Technical University, Earthquake Engineering and Disaster Management Institute, 34469, Maslak, Istanbul (Turkey); Arda, L., E-mail: lutfi.arda@bahcesehir.edu.tr [Bahcesehir University, Faculty of Arts and Sciences, Department of Mathematics and Computer Sciences, Ciragan Cad, Osmanpasa Mektebi Sok, 34349, Besiktas, Istanbul (Turkey); Ozturk, O.; Asikuzun, E. [Kastamonu University, Faculty of Arts and Sciences, Department of Physics, 37100, Kastamonu (Turkey); Akcan, D. [Bahcesehir University, Faculty of Arts and Sciences, Department of Mathematics and Computer Sciences, Ciragan Cad, Osmanpasa Mektebi Sok, 34349, Besiktas, Istanbul (Turkey); Cakiroglu, O. [Hasan Ali Yucel Education Faculty, Istanbul University, 34452, Beyazit, Istanbul (Turkey)

2014-01-10

This study reports the effect of annealing temperature on the structure and mechanical properties of Zn{sub 0.95}Mg{sub 0.05}O bulk samples by using digital Vickers microhardness tester, X-ray diffraction analysis, scanning electron microscopy and electron dispersive X-ray measurements. The samples were prepared using Zn and Mg based alkoxed by the sol–gel technique and annealed at various temperatures (500, 600, 700 and 800 °C). Vickers microhardness, elastic modulus, yield strength and fracture toughness values of Zn{sub 0.95}Mg{sub 0.05}O bulk samples were separately calculated and compared with each other. The experimental results of hardness measurements were analyzed using Meyer's law, Proportional Specimen Resistance (PSR) and Elastic/Plastic Deformation (EPD) models and Hays–Kendall (HK) approach. Finally, it was seen that HK approach is the most successful model for the microhardness analysis of these materials.

The development and application of portable speed tester for special equipment

International Nuclear Information System (INIS)

Lan Peng; Chen Ligang; Dai Sidan; Wang Huiting; Zhang Liangxu; Wang Lin

2014-01-01

Special equipment developed to meet the needs for research and industrial application of this stage, with the advantages of small size, high accuracy, long working hours, high reliability and intelligent portable speed tester. This paper describes the development and application of the tester. In terms of hardware, the tester use 'MCU + CPLD' to build the core of the system, and focus on high precision, low-power design, Software to increase their power electricity monitoring and filtering software anti-interference function. The tester can achieve high-precision measurement of the speed parameter, display measurement data in real time via the LCD display functions. Currently, the tester has been successfully achieved industrial application. (authors)

Room temperature Young's modulus, shear modulus, Poisson's ratio and hardness of PbTe-PbS thermoelectric materials

Energy Technology Data Exchange (ETDEWEB)

Ni, Jennifer E [Chemical Engineering and Materials Science Department, Michigan State University, East Lansing, MI 48824 (United States); Case, Eldon D., E-mail: casee@egr.msu.edu [Chemical Engineering and Materials Science Department, Michigan State University, East Lansing, MI 48824 (United States); Khabir, Kristen N; Stewart, Ryan C [Chemical Engineering and Materials Science Department, Michigan State University, East Lansing, MI 48824 (United States); Wu, Chun-I; Hogan, Timothy P [Electrical and Computer Engineering Department, Michigan State University, East Lansing, MI 48824 (United States); Timm, Edward J [Mechanical Engineering Department, Michigan State University, East Lansing, MI 48824 (United States); Girard, Steven N; Kanatzidis, Mercouri G [Department of Chemistry, Northwestern University, Evanston, IL (United States)

2010-06-15

Two-phase PbTe-PbS materials, in which PbS is a nanostructured phase, are promising thermoelectric materials for the direct conversion of heat energy into electricity. In this study, a Vickers indentation mean hardness of 1.18 {+-} 0.09 GPa was measured for hot pressed specimens Pb{sub 0.95}Sn{sub 0.05}Te-PbS 8% while the mean hardness of cast specimens was 0.68 {+-} 0.07 GPa. The mean fracture toughness of the not pressed specimens was estimated as 0.35 {+-} 0.04 MPa m{sup 1/2} via Vickers indentation. Resonant Ultrasound Spectroscopy (RUS) measurements on hot pressed specimens gave mean values of Young's modulus, shear modulus and Poisson's ratio of 53.1 GPa, 21.4 GPa and 0.245, respectively while for the cast specimens the Young's and shear moduli were about 10% lower than for the hot pressed, with a mean value of Poisson's ratio of 0.245. The differences between the hardness and elastic moduli values for the cast and hot pressed specimens are discussed.

Corrosive environment tester for filter media

International Nuclear Information System (INIS)

Petit, G.S.; Weber, C.W.; Keinberger, C.A.; Rivers, R.D.

1977-02-01

Two continuous dynamic systems have been designed and fabricated for testing filter media in humid, corrosive environments--one for fluorine or fluoride exposures, and the other for nitrogen dioxide exposures. The tester using fluorine or fluoride atmospheres was constructed of nickel and the one using nitrogen dioxide was fabricated of stainless steel. Other corrosive gases could be used with the appropriate choice of system. For example, chlorine or hydrogen chloride could be used in the system fabricated of nickel, and sulfur dioxides or ammonia could be used in the stainless steel testing apparatus. Each tester is comprised of four equivalent dynamic systems designed for diluting a corrosive reagent with dry air, then with humidified air to provide a humid-corrosive environment for filter media testing. Auxiliary equipment includes a water injection system, corrosive reagent supply systems, and an automatic pressure differential (ΔP) monitoring and recording system. The testers are relatively maintenance-free and have operated continuously for periods as long as 96 h without requiring any attention, during total exposures of materials exceeding 600 h

Enhanced properties of nanostructured TiO2-graphene composites by rapid sintering

Science.gov (United States)

Shon, In-Jin; Yoon, Jin-Kook; Hong, Kyung-Tae

2018-01-01

Despite of many attractive properties of TiO2, the drawback of TiO2 ceramic is low fracture toughness for widely industrial application. The method to improve the fracture toughness and hardness has been reported by addition of reinforcing phase to fabricate a nanostructured composite. In this regard, graphene has been evaluated as an ideal second phase in ceramics. Nearly full density of nanostructured TiO2-graphene composite was achieved within one min using pulsed current activated sintering. The effect of graphene on microstructure, fracture toughness and hardness of TiO2-graphene composite was evaluated using Vickers hardness tester and field emission scanning electron microscopy. The grain size of TiO2 in the TiO2-x vol% (x = 0, 1, 3, and 5) graphene composite was greatly reduced with increase in addition of graphene. Both hardness and fracture toughness of TiO2-graphene composites simultaneously increased in the addition of graphene.

24 CFR 125.107 - Testers.

Science.gov (United States)

2010-04-01

... perjury. (b) Testers must receive training or be experienced in testing procedures and techniques. (c...; (3) Have had any employment or other affiliation, within one year, with the person or organization to...

The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian

Directory of Open Access Journals (Sweden)

Daniela Ogrean

2001-04-01

Full Text Available The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Timiş district and between 539–958 respectively, in case of the Racoş basalts (Braşov district. There is a certain variation of the hardness within the same sample, in various measurement points, within the theoretical limits of the hardnesses of the pyroxenes and that of the spinels.

Advanced TCA BAckplane Tester

CERN Document Server

Oltean, Alexandra Dana; PGNet2005

2005-01-01

The “Advanced Telecom Computing Architecture” (AdvancedTCA) is a modular standard chassis based system designed to support the needs of carrier class telecommunication applications. It is defined by a set of industry standards under the direction of the PICMG group. One early deployment of the standard technology has been a 10 Gigabit Ethernet switch developed in the framework of the EU funded ESTA project. In order to study the practical aspects of high speed Ethernet switching at 10 Gigabit and above and to validate the signal integrity of the AdvancedTCA backplane, we developed a Backplane Tester. This system is able to run pseudo-random bit sequence (PRBS) traffic at 3.125 Gbps over every link on the AdvancedTCA backplane simultaneously, and to monitor any possible connectivity failure immediately in terms of the link and slot positions inside the chassis. In this paper, we describe the design and the practical architectural hardware and software aspects of the AdvancedTCA Backplane Tester. We also pr...

Effects of Wet and Dry Finishing and Polishing on Surface Roughness and Microhardness of Composite Resins

Science.gov (United States)

Nasoohi, Negin; Hoorizad, Maryam

2017-01-01

Objectives: This study aimed to assess the effect of wet and dry finishing and polishing on microhardness and roughness of microhybrid and nanohybrid composites. Materials and Methods: Thirty samples were fabricated of each of the Polofil Supra and Aelite Aesthetic All-Purpose Body microhybrid and Grandio and Aelite Aesthetic Enamel nanohybrid composite resins. Each group (n=30) was divided into three subgroups of D, W and C (n=10). Finishing and polishing were performed dry in group D and under water coolant in group W. Group C served as the control group and did not receive finishing and polishing. Surface roughness of samples was measured by a profilometer and their hardness was measured by a Vickers hardness tester. Data were analyzed using two-way ANOVA (Pcomposites (Pcomposites (Pcomposites (Pcomposite resins. PMID:29104597

Dall-Null tester for spaceborne applications

Science.gov (United States)

Wingler, R. L.

1984-12-01

This is a study to design a self correcting primary mirror system for a space telescope. The design is centered around a Dall-Null tester (a Foucault knife-edge tester with compensating lens). An indepth study of the theory of the Foucault test from Foucault's original publications to current work is presented. Also short comings of the diffraction approach are shown. The findings of a simple experiment showed the way to the correct explanation as to the workings of the test. Based on this new explanation, a computer program to find the error in the surface of the mirror from the irradiance pattern provided by the Dall-Null tester was developed. The computer program with a sample run is included in the appendixes A and B. The basic design of an adaptive optic system for a spaceborne application is also presented in the paper. This design has the desired quality of being able to correct the mirror while the telescope is in use. The equations being independent of wavelength allows for the design to be applied to systems working outside of the visible spectrum as well as the systems working in the visible.

Effects of multiple firings on the microstructure of zirconia and veneering ceramics.

Science.gov (United States)

Alkurt, Murat; Yeşil Duymus, Zeynep; Gundogdu, Mustafa

2016-01-01

The aim of study was to evaluate the effects of multiple firings on the microstructures of zirconia and two ceramics. Vita VM9 (VMZ) and Cerabien ZR (C-Z) ceramics on a zirconia framework and zirconia without veneering ceramic (WO-Z) were evaluated. Firing methods included firing two, five, and ten times (n=10). The effects of multiple firings on the surface hardness of the materials were evaluated using a Vickers hardness (HV) tester. Data were analyzed by two-way ANOVA and Tukey's test (α=0.05). After firing five and ten times, the hardness of VM-Z and C-Z increased significantly (p0.05). In the XRD analysis, zirconia had similar tetragonal (t)-monoclinic (m) phase transformations of Y-TZP after the different firing times. Clinically, multiple firings did not affect the microstructure of zirconia, but the structures of the two ceramics were affected.

Comparative investigations of tablet crushing force testers

DEFF Research Database (Denmark)

Sonnergaard, Jørn; Jensen, C.G.; Poulsen, L.

2005-01-01

The performance of 16 tablet breaking force testers was evaluated in terms of accuracy, reproducibility and repeatability. Three tablet formulations with different plastic or brittle deformation mechanisms and with target breaking forces of 50, 100 and 150 N were tested. Statistically significant...... by the concept of components of variance was 5-7 % depending on the model tablet excipient. The standard deviation within testers (repeatability) was affected by the type of model formulation showing increasing variability with increasing brittleness of the compressed material. No specific effect of altering...

Comparative examination of the microstructure and high temperature oxidation performance of NiCrBSi flame sprayed and pack cementation coatings

Science.gov (United States)

Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Skolianos, S.; Chrissafis, K.; Stergioudis, G.

2009-01-01

Coatings formed from NiCrBSi powder were deposited by thermal spray and pack cementation processes on low carbon steel. The microstructure and morphology of the coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Flame sprayed coatings exhibited high porosity and were mechanically bonded to the substrate while pack cementation coatings were more compact and chemically bonded to the substrate. The microhardness and the high temperature oxidation resistance of the coated samples were evaluated by a Vickers microhardness tester and by thermogravimetric measurements (TG), respectively. Pack cementation coatings showed higher hardness and were more protective to high temperature environments than the flame sprayed coatings.

Armstrong Laboratory Space Visual Function Tester Program

Science.gov (United States)

Oneal, Melvin R.; Task, H. Lee; Gleason, Gerald A.

1992-01-01

Viewgraphs on space visual function tester program are presented. Many astronauts and cosmonauts have commented on apparent changes in their vision while on-orbit. Comments have included descriptions of earth features and objects that would suggest enhanced distance visual acuity. In contrast, some cosmonaut observations suggest a slight loss in their object discrimination during initial space flight. Astronauts have also mentioned a decreased near vision capability that did not recover to normal until return to earth. Duntley space vision experiment, USSR space vision experiments, and visual function testers are described.

Wear Resistance Properties Reinforcement Using Nano-Al/Cu Composite Coating in Sliding Bearing Maintenance.

Science.gov (United States)

Liu, Hongtao; Li, Zhixiong; Wang, Jianmei; Sheng, Chenxing; Liu, Wanli

2018-03-01

Sliding bearing maintenance is crucial for reducing the cost and extending the service life. An efficient and practical solution is to coat a restorative agent onto the worn/damaged bearings. Traditional pure-copper (Cu) coating results in a soft surface and poor abrasion resistance. To address this issue, this paper presents a nano-composite repairing coating method. A series of nano-Al/Cu coatings were prepared on the surface of 45 steel by composite electro-brush plating (EBP). Their micro-hardness was examined by a MHV-2000 Vickers hardness tester, and tribological properties by a UMT-2M Micro-friction tester, 3D profiler and SEM. Then, the influence of processing parameters such as nano-particle concentration and coating thickness on the micro-hardness of nano-Al/Cu coating was analyzed. The experimental analysis results demonstrate that, when the nano-Al particle concentration in electrolyte was 10 g/L, the micro-hardness of the composite coating was 1.1 times as much as that of pure-Cu coating. When the Al nano-particle concentration in electrolyte was 20 g/L, the micro-hardness of the composite coating reached its maximum value (i.e., 231.6 HV). Compared with the pure-Cu coating, the hardness and wear resistance of the nano-composite coating were increased, and the friction coefficient and wear volume were decreased, because of the grain strengthening and dispersion strengthening. The development in this work may provide a feasible and effective nano-composite EBP method for sliding bearing repair.

Fabrication of Al-20 wt%Si powder using scrap Si by ultra high-energy milling process

Energy Technology Data Exchange (ETDEWEB)

Kang, Won-Kyung [Division of Advanced Materials Engineering and Institute for Rare Metals, Kongju National University, 275, Budae-dong, Cheonan, Chungnam 330-717 (Korea, Republic of); Y Latin-Small-Letter-Dotless-I lmaz, Fikret [Department of Physics, Faculty of Art and Science, Gaziosmanpasa University, Tasliciftlik Campus, 60240 Tokat (Turkey); Kim, Hyo-Seob; Koo, Jar-Myung [Division of Advanced Materials Engineering and Institute for Rare Metals, Kongju National University, 275, Budae-dong, Cheonan, Chungnam 330-717 (Korea, Republic of); Hong, Soon-Jik, E-mail: hongsj@kongju.ac.kr [Division of Advanced Materials Engineering and Institute for Rare Metals, Kongju National University, 275, Budae-dong, Cheonan, Chungnam 330-717 (Korea, Republic of)

2012-09-25

Highlights: Black-Right-Pointing-Pointer High energy ball milling process has been successfully employed to produce Al-20Si alloy using scrap Si powders. Black-Right-Pointing-Pointer Fully finer and homogenous structure could be achieved after 60 min of milling time. Black-Right-Pointing-Pointer Si particles were not dissolved but uniformly dispersed in the Al matrix in a milled state. Black-Right-Pointing-Pointer The hardness of as-milled Al-20Si powder increased steadily with the increase of milling time. Black-Right-Pointing-Pointer Grain size and dispersion strengthening are two mechanisms being responsible for hardness increment. - Abstract: In this study, microstructural evolution and mechanical properties of Al-20 wt%Si and pure Al powders fabricated by ultra high-energy ball milling technique were investigated as a function of milling time. The microstructure and mechanical properties of the as-milled powders were examined by scanning electron microscope (SEM), energy dispersive spectrometry (EDS), X-ray diffractometer (XRD) and Vickers hardness tester. SEM observation showed that the particle size increased at an early stage of milling, and then decreased drastically with further milling. XRD and cross-sectional EDS-mapping analyses revealed that Si particles were not dissolved but uniformly dispersed in the Al matrix in a milled state. Vickers hardness of both pure Al and Al-Si powder increases with milling time, which attributes to the grain size strengthening and dispersion strengthening.

Perbedaan Penggunaan Bahan Desensitizing dan Tanpa Desensitizing Pasca Bleaching Ekstra-Koronal terhadap Kekerasan Email

Directory of Open Access Journals (Sweden)

Wignyo Hadriyanto

2012-12-01

Full Text Available Latar Belakang. Pada bleaching ekstrakoronal diketahui terjadi proses demineralisasi sehingga terjadi hiersensitivitas dentin. UltraEZ salah satu bahan desensitizing yang dapat mengurangi hipersensitivitas akibat demineralisasi email pasca bleaching ekstrakoronal terkini. Tujuan penelitian ini bertujuan untuk mengetahui perbedaan kekerasan email pasca pemutihan gigi ekstra-koronal dengan aplikasi bahan desensitizing dan tanpa aplikasi bahan desensitizing. Metode penelitian ini menggunakan 20 gigi premolar permanen pasca pencabutanyang masih utuh dan direndam dalam saliva buatan, kemudian dilakukan pemolesan pada bagian bukal dengan menggunakan pasta profilaksis kemudian gigi dicuci dan dikeringkan. Bahan pemutih Opalescence Xtra Boost diaplikasikan pada semua permukaan bukal gigi premolar kemudian dibagi menjadi 2 kelompok yaitu kelompok I, II, masing-masing kelompok sebanyak 10 gigi. Kelompok I sebagai kelompok control setelah dilakukan pemutihan, tidak dilakukan aplikasi Ultra-EZ, dimasukkan dalam wadah botol dan direndam dalam saliva buatan kemudian disimpan dalam incubator. Mahkota dan akar gigi,kemudian ditanam dalam resin akrilik sesuai kelompok sebelumnya dengan permukaan bukal menghadap ke atas. Semua sampel diuji kekerasannya dengan uji kekerasan Vickers menggunakan beban 100 g selama 15 detik. Permukaan bukal menghadap ke atas, kemudian dijepit dengan alat penjepit pada meja alat Micro Vickers Hardness Tester. Sampel diatur sedemikian rupa sehingga akan terlihat gambar yang dapat diukur panjang diagonalnya langsung dengan micrometer yang ada pada lensa okuler. Nilai kekerasan email dalam Vickers hardness number (VHN juga dapat diperoleh dari table setelah mengetahui rata-rata panjang diagonal, berat badan yang digunakan dan waktu yang digunakan untuk uji kekerasan. Pengujian ini dilakukan pada setiap kelompok. Selanjutnya diuji dengan uji-t. hasil penelitian menunjukkan ada perbedaan yang bermakna antara aplikasi ultraEZ lima menit

Effect of sintering atmosphere on the hardness of ThO2

Science.gov (United States)

Baena, Angela; Cardinaels, Thomas; Van Eyken, Jelle; Puzzolante, Jean Louis; Binnemans, Koen; Verwerft, Marc

2016-08-01

The hardness and toughness of ThO2 sintered under reducing and oxidizing conditions has been investigated and, quite unexpectedly, a significant difference in hardness was observed for the entire range of porosities studied. Reducing conditions systematically yielded higher hardness values than oxidizing conditions. Extrapolated to zero porosity, the hardness for ThO2 is H0 = 10.5 ± 0.3 GPa for oxidizing conditions and H0 = 12.4 ± 0.7 GPa for reducing conditions. Toughness values have been derived from Vickers indentations; differences in toughness were insignificant and only a single value is proposed: KIC = 0.97 ± 0.12 MPa √m. The difference in hardness is attributed to the presence of point defects, also acting as color centers and causing grey coloration of ThO2 sintered under reducing conditions. Furthermore, and of interest for nuclear fuel production, is the finding that ThO2 sintered under reducing conditions is significantly easier to grind compared to material sintered under oxidizing conditions.

Influence of temperature, grain size and cobalt content on the hardness of WC-Co alloys

CSIR Research Space (South Africa)

Milman, YV

1999-01-01

Full Text Available temperatures: ?196, ?80, 20, 200, 300, 400, 500, 600, 700, 800 and 900?C. In the range 20?900?C the hardness is measured using a 60 N load in a BIM-1 installation [2] in a vacuum of about 10?3 Pa. In this installation the load on the Vickers indenter...

Production and mechanical properties of sintered carbides (hard steels WC-Co)

International Nuclear Information System (INIS)

Batalha, G.F.

1987-09-01

Densification and mechanical characteristics or WC-Co Cemented Carbides, were investigated by dilatometry, Hardness and bending tests, as a function of the two principal micro-structural parameters: the cobalt content and the particle size of carbide crystals. Vickers hardness of the studied compositions showed a linear variation with the increase of the cobalt content. By three point bending, the transverse rupture strenght increases with cobalt content, however, for larger grain size reaches a maximum, eventually reduced by brittle phases and incomplete dispersion. The results of brittle facture tests were statistically analised and fitted better to the 'Weakest Link Model' (Weibull distribution) than the 'Chain Model' (Gaussian distribution). (author) [pt

Tester status report: April-June 1979

Energy Technology Data Exchange (ETDEWEB)

Draut, C.F.

1979-08-31

This report details tester status and activities in support of testing of timers, actuators, detonators, firing sets, transducers, isolators, and pyrospacers for the period of April through June 1979.

Theoretical Conversions of Different Hardness and Tensile Strength for Ductile Materials Based on Stress-Strain Curves

Science.gov (United States)

Chen, Hui; Cai, Li-Xun

2018-04-01

Based on the power-law stress-strain relation and equivalent energy principle, theoretical equations for converting between Brinell hardness (HB), Rockwell hardness (HR), and Vickers hardness (HV) were established. Combining the pre-existing relation between the tensile strength ( σ b ) and Hollomon parameters ( K, N), theoretical conversions between hardness (HB/HR/HV) and tensile strength ( σ b ) were obtained as well. In addition, to confirm the pre-existing σ b -( K, N) relation, a large number of uniaxial tensile tests were conducted in various ductile materials. Finally, to verify the theoretical conversions, plenty of statistical data listed in ASTM and ISO standards were adopted to test the robustness of the converting equations with various hardness and tensile strength. The results show that both hardness conversions and hardness-strength conversions calculated from the theoretical equations accord well with the standard data.

Comparison of Mechanical Properties of Resin Composites with Resin Modified Glass Ionomers

Directory of Open Access Journals (Sweden)

Taha NA

2015-06-01

Full Text Available Statement of Problem: There are controversial reports regarding physical and mechanical properties of resin composites and glass ionomer cements. Some revealed higher strength and hardness for resin composites while others showed a comparable value for glass ionomer cements. Evaluation of mechanical properties of different types of resin composites in comparison with resin modified glass ionomers is not widely studied. Objectives: To measure and compare the flexural strength and Vickers hardness of three resin composites and two resins modified glass ionomer cements before and after ageing. Materials and Methods: Three resin composites, i.e. Filtek Supreme XTE (3M ESPE, Ice (SDI, Gradia (GC, and two resins modified glass ionomers, i.e. Fuji II LC (GC and Riva Light Cure (SDI, were selected. Ten barshaped specimens were prepared for each material and cured using LED curing light. After 24 hours storage in distilled water at 37oC, the specimens were randomly divided into two equal groups (n=5. The first group was tested as a baseline and the second group was restored at 37oC for another 29 days. Flexural strength was performed by four-point bending test using universal testing machine at crosshead speed of 0.5mm/min, and the maximum load at failure was recorded. The specimen’s halves were used for evaluating Vickers hardness, using a Digital Hardness Tester (300 g/15 sec and the Vickers hardness number (VHN was recorded. Data were analyzed using one-way analysis of variance (ANOVA, Tukey’s and student’s t-test. Results: After 24 hours of immersion, the highest hardness number was found for Filtek Supreme and Ice and the highest flexural strength was obtained for Gradia. After 30 days of storage, hardness of Fuji II LC and Gradia showed a significant decrease; flexural strength of Ice and Fuji II LC revealed a significant increase while Gradia and Filtek Supreme showed a significant decrease. Conclusions: Resin modified glass ionomers showed

Microstructure and properties of high chrome steel roller after laser surface melting

International Nuclear Information System (INIS)

Li Meiyan; Wang Yong; Han Bin; Zhao Weimin; Han Tao

2009-01-01

Laser surface melting of high chrome steels was achieved by a 5 kW continuous wave CO 2 laser. The microstructure of the laser surface-melted steels was investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffractometry, and the hardness profiles were determined by a Vickers hardness tester. The corrosion behavior in 3.5% NaCl solution was studied by electrochemical corrosion equipment. The large carbides of high chrome steels are completely dissolved and ultrafine dendrites of austenite with submicroscopic M 23 C 6 carbides precipitation are formed in the melted zone. The austenite in the melted zone has a high tempering stability. The corrosion resistance of the laser surface-melted steels is significantly improved due to the dissolution of carbides and the increase of the alloying elements in the solid solution as well as the large amount of austenite.

Development of the tyre tester

CSIR Research Space (South Africa)

Kuduntwane, P

2012-10-01

Full Text Available of the tyre tester P KUDUNTWANE1, DU PLESSIS2 AND PROF. S ELS3 1CSIR Defence, Peace, Safety and Security, PO Box 395, Pretoria, South Africa, 0001 2Department of Mechanical Engineering, Central University of Technology, Private Bag X20539, Bloemfontein...

Comparison of mechanical properties of three machinable ceramics with an experimental fluorophlogopite glass ceramic.

Science.gov (United States)

Leung, Brian T W; Tsoi, James K H; Matinlinna, Jukka P; Pow, Edmond H N

2015-09-01

Fluorophlogopite glass ceramic (FGC) is a biocompatible, etchable, and millable ceramic with fluoride releasing property. However, its mechanical properties and reliability compared with other machinable ceramics remain undetermined. The purpose of this in vitro study was to compare the mechanical properties of 3 commercially available millable ceramic materials, IPS e.max CAD, Vitablocs Mark II, and Vita Enamic, with an experimental FGC. Each type of ceramic block was sectioned into beams (n=15) of standard dimensions of 2×2×15 mm. Before mechanical testing, specimens of the IPS e.max CAD group were further fired for final crystallization. Flexural strength was determined by the 3-point bend test with a universal loading machine at a cross head speed of 1 mm/min. Hardness was determined with a hardness tester with 5 Vickers hardness indentations (n=5) using a 1.96 N load and a dwell time of 15 seconds. Selected surfaces were examined by scanning electron microscopy and energy-dispersive x-ray spectroscopy. Data were analyzed by the 1-way ANOVA test and Weibull analysis (α=.05). Weibull parameters, including the Weibull modulus (m) as well as the characteristic strength at 63.2% (η) and 10.0% (B10), were obtained. A significant difference in flexural strength (PVita Enamic (145.95 ±12.65 MPa)>Vitablocs Mark II (106.67 ±18.50 MPa), and FGC (117.61 ±7.62 MPa). The Weibull modulus ranged from 6.93 to 18.34, with FGC showing the highest Weibull modulus among the 4 materials. The Weibull plot revealed that IPS e.max CAD>Vita Enamic>FGC>Vitablocs Mark II for the characteristic strength at both 63.2% (η) and 10.0% (B10). Significant difference in Vickers hardness among groups (PVitablocs Mark II (594.74 ±25.22 H(V))>Vita Enamic (372.29 ±51.23 H(V))>FGC (153.74 ±23.62 H(V)). The flexural strength and Vickers hardness of IPS e.max CAD were significantly higher than those of the 3 materials tested. The FGC's flexural strength was comparable with Vitablocs Mark II

Effects of applying anchovy (Stolephorus insularis) substrates on the microhardness of tooth enamel in Sprague-Dawley rats

Science.gov (United States)

Hendrik, Y. C.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Anchovies (Stolephorus insularis) contain high levels of fluor in the form of CaF2. The aim of this study is to analyze changes in tooth enamel microhardness after application of anchovy substrates by feeding or as a topical fluoridation material. An in vivo study of the lower left incisors of nine Sprague-Dawley rats was conducted. The sample was comprised of baseline and treatment groups, including feeding application, topical application, negative control feeding, and negative control topical groups. The treatment groups were given 5% anchovy substrates through feeding and topical applications. After treatment, tooth samples were extracted from each of the rats for examination, and statistical analyses were performed after determining hardness numbers for enamel surfaces using Vickers microhardness tester. Vickers hardness numbers (VHNs) for anchovy substrate application and consumption by feeding (440.3 ± 24.72) were higher than for the negative control (315.80 ± 17.51). VHNs for the topical application group were higher than for the negative control (347.28 ± 28.56) and for the feeding group. The use of anchovy as a fluoridation material in form of topical application is potentially an effective method for increasing the microhardness of the tooth enamel surface

The In vitro Evaluation of the effect of xyliwhite, probiotic, and the conventional toothpastes on the enamel roughness and microhardness.

Science.gov (United States)

Maden, E Arat; Altun, C; Polat, G Guven; Basak, F

2018-03-01

The aim of this study was to evaluate the effect of fluoride, Xylitol, Probiotic, and Whitening toothpastes on the permanent teeth enamel roughness and microhardness. One hundred and twenty teeth were randomly divided into 2 groups, each group having 60 samples. G1: The group in which enamel roughness was examined (n = 60). G2: The group in which enamel microhardness was examined (n = 60). Then, these groups were randomly divided into 4 groups among themselves (n = 15). Each group was brushed using four different toothpastes for 1 week with a battery-powered toothbrush in the morning and evening for 2 min. Vicker's hardness tester was used to measure the changes in microhardness, and the profilometer was used to measure the changes in surface roughness. No statistically significant differences were found on surface roughness and microhardness values measured after tooth brushing process in group brushed with Colgate MaxFresh toothpaste (P > 0.01). Statistically significant decrease was observed on Vicker's hardness values measured after tooth brushing process in groups brushed with Ipana White Power Carbonate toothpaste, Xyliwhite Toothpaste Gel, and Periobiotic Probiotic Toothpaste (P tooth enamel surface roughness and microhardness. Xyliwhite, Periobiotic, and Ipana White Power Carbonate-containing abrasive toothpastes led to changes negatively on permanent tooth enamel surface roughness and microhardness.

Development of roller type side slip tester; Roller shiki side slip tester no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Nishiyama, S [Hiroshima City Industrial Technology Institute, Hiroshima (Japan); Harada, S; Harada, K

1997-10-01

This paper presents a new development of roller type side slip tester (RTSSI). The test equipment consists of four parts, which are developed in this research. These are a roller part, a control part, a remote control part and a CRT part. In this study, we especially investigated the mechanism and performance between tire and roller. We analyzed the amount of side slip with various toe angles. The developed tester is examined under the conditions that is considered in industrial applications. We investigated the influences of toe angle, size of tire, pressure of tire, coefficient of friction between tire and roller, pushing force of tire, revolution velocity of roller, axle load and so on. The validity of the developed RTSST is confirmed under these conditions. It was found that the RTSST can be used in practical use. Some measurement results are presented in the form of parametric plots. And we also compared measurements data between the RTSST and that of flat type using several automobiles. 4 refs., 8 figs., 4 tabs.

Finite element analysis of stresses in Berkovich, Vickers and Knoop indentation for densifying and non-densifying glasses

Science.gov (United States)

Chen, Kanghua

2002-08-01

during a material removal experiment of magnetorheological finishing (MRF) of fused silica. The explanation of indentation size effect (ISE) is attempted using numerical indentation simulations. Vickers indentation simulations on the five selected brittle materials (FS, BK7, Si, LHG8 and CaF2.) show no size dependence of Vickers hardness when the material is modeled as elastic-perfectly plastic (with or without densification). The simulation results on axisymmetric conical indentation also indicate that the bluntness of the indenter tip is not the reason for the indentation size effect. A new constitutive model accounting for the material length scale is needed in order to explain the well-observed indentation size effect during indentation tests.

Product-Improvement Test (Phase II), Jetcal Tester, Model H119A.

Science.gov (United States)

1969-03-05

Ao—A0 51 113 ARMY AVIATION ‘Cs’ BOARD FORT tUCKER ALA — P*OOUCTeII ROVEMCNT TEST ( FHAS ~ I I ) . JETCAL TESTER, MODEL M119A~~’ETC(U) MAR S9...Phase i i ) , Jetcal Tester , Model H 119A , USATECOM Project No. 4-6-5011-03 b . No fur ther consideration be given to the TEMPCAL heater probe as a...essen t i a l component of the Jetcal Tester. e. The service manual instruct ions for con t inu i ty te s t ing of EG1 thermocouples be revised to

Tester of the TRT front-end electronics for the ATLAS-experiment

CERN Document Server

Hajduk, Z; Kisielewski, B; Kotarba, A; Malecki, P; Natkaniec, Z; Olszowska, J; Ostrowicz, W; Krupinska, G

2000-01-01

The VME based tester for front-end electronics of the TRT (Transition Radiation Tracker) detector of the ATLAS-LHC experiment at CERN, Geneva, is described. The TRT read-out electronics for 424576 proportional tubes grouped on many thousands of cards requires stringent quality control after assembly and during installation. The tester provides all required data, pulses, timing and power supplies for tested cards. The essential part of the tester is its software that allows for device handling as well as facilitates functional and statistical tests. The prototype, present design as well as the new design for mass production tests are discussed. (17 refs).

An investigation into the mechanical and tribological properties of plasma electrolytic oxidation and hard-anodized coatings on 6082 aluminum alloy

International Nuclear Information System (INIS)

Malayoglu, Ugur; Tekin, Kadir C.; Malayoglu, Ufuk; Shrestha, Suman

2011-01-01

Highlights: → Mechanical properties of PEO and anodised coatings were studied using ultra-micro hardness tester. → Elastic modulus and hardness of the PEO coating were found much higher than those of the anodised coating. → Improved sliding wear of PEO coating is due to presence of hard α and γ-Al 2 O 3 phases. - Abstract: A ceramic coating on AA6082 aluminum alloy prepared by plasma electrolytic oxidation (PEO) has been studied and compared against a sulphuric acid hard-anodized coating on the same alloy. Surface morphology and microstructures of the coatings have been examined by scanning electron microscopy. X-ray diffraction is used to determine the phase composition of the coatings. The adhesion strength of the coatings has been evaluated using a scratch test method. The coating's mechanical properties such elastic modulus and hardness data have been generated using a dynamic ultra-microhardness tester. Sliding wear tests with different loading rates are performed on the coatings in order to assess their wear resistance. Test results show that the PEO treated samples exhibit significantly better mechanical properties compared to hard anodized samples. The elastic modulus and hardness of the PEO coating are 2-3 times greater than of the hard anodized coating and subsequently, an improved wear resistance of the PEO coating has been achieved. The mechanical properties of the coatings and their relations to their tribological performance are discussed.

Corrosion resistance and mechanical properties of pulse electrodeposited Ni-TiO{sub 2} composite coating for sintered NdFeB magnet

Energy Technology Data Exchange (ETDEWEB)

Li Qing, E-mail: liqingd@swu.edu.c [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yang Xiaokui [School of Materials Science and Engineering, Southwest University, Chongqing 400715 (China); Zhang Liang; Wang Juping; Chen Bo [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

2009-08-12

Ni-TiO{sub 2} composite coating which was prepared under pulse current conditions was successfully performed on sintered NdFeB magnet. As a comparison, pure nickel coating was also prepared. The phase structure, the surface morphology, the chemical composition, the anti-corrosion performance of the coatings for magnets, the microhardness and the wearing resistance performance of the coatings were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), electrochemical technique, Vickers hardness tester and ball-on-disc tribometer, respectively. The results revealed that Ni-TiO{sub 2} composite coating provided excellent anti-corrosion performance for the magnets, and showed higher microhardness and better anti-wear performance.

Post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin

International Nuclear Information System (INIS)

Yap, A.U.J.

1997-01-01

This study examined the post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin using a digital microhardness tester. Change in hardness of these materials over a period of 6 months was compared to that of conventional glass ionomer cements and a composite resin. With the exception of the composite resin, all materials showed a significant increase in hardness over 24 h after their initial set. Dual-cure resin-modified glass ionomer cements showed decreased hardness with increased storage time in saline at 37 o C. Results suggest that the addition of resins to glass ionomer cements does not improve initial hardness and does not negate the acid-base reaction of conventional cements. Resin addition may, however, lead to increased water sorption and decreased hardness. (author)

Tribological properties of ion-implanted steels

International Nuclear Information System (INIS)

Iwaki, Masaya

1987-01-01

The tribological properties such as surface hardness, friction and wear have been studied for low carbon steels and tool steels implanted with many types of ion including metallic elements. The hardness measured by Vickers or Knoop hardness testers as a function of normal load is dependent on the implanted species, fluence and substrate. The friction coefficients measured by Bowden-Leben type of friction tests or detected during wear tests also depend on the implantation conditions. The improvement in the wear resistance, which is most important for industrial use of implanted materials, has been investigated for AISI H13 prehardened and tool steels implanted with nitrogen and boron ions. The relationship between hardness, friction and wear is discussed in comparison with the microcharacteristics such as composition and chemical bonding states measured by means of secondary ion mass spectrometry and X-ray photoelectron spectroscopy. It is concluded that the increase in hardness and/or the decrease in friction coefficient play(s) an important role in improving the wear resistance, and the relationship between relative wear volume and relative hardness is correlated for boron and nitrogen implantation. (orig.)

Residual stresses around Vickers indents

International Nuclear Information System (INIS)

Pajares, A.; Guiberteau, F.; Steinbrech, R.W.

1995-01-01

The residual stresses generated by Vickers indentation in brittle materials and their changes due to annealing and surface removal were studied in 4 mol% yttria partially stabilized zirconia (4Y-PSZ). Three experimental methods to gain information about the residual stress field were applied: (i) crack profile measurements based on serial sectioning, (ii) controlled crack propagation in post indentation bending tests and (iii) double indentation tests with smaller secondary indents located around a larger primary impression. Three zones of different residual stress behavior are deduced from the experiments. Beneath the impression a crack free spherical zone of high hydrostatic stresses exists. This core zone is followed by a transition regime where indentation cracks develop but still experience hydrostatic stresses. Finally, in an outward third zone, the crack contour is entirely governed by the tensile residual stress intensity (elastically deformed region). Annealing and surface removal reduce this crack driving stress intensity. The specific changes of the residual stresses due to the post indentation treatments are described and discussed in detail for the three zones

Microstructure and properties of high chrome steel roller after laser surface melting

Energy Technology Data Exchange (ETDEWEB)

Li Meiyan, E-mail: lmy_102411@163.com [College of Electromechanical Engineering, China University of Petroleum, 271 Bei' er Road, Dongying 257061 (China); Wang Yong; Han Bin; Zhao Weimin; Han Tao [College of Electromechanical Engineering, China University of Petroleum, 271 Bei' er Road, Dongying 257061 (China)

2009-06-15

Laser surface melting of high chrome steels was achieved by a 5 kW continuous wave CO{sub 2} laser. The microstructure of the laser surface-melted steels was investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffractometry, and the hardness profiles were determined by a Vickers hardness tester. The corrosion behavior in 3.5% NaCl solution was studied by electrochemical corrosion equipment. The large carbides of high chrome steels are completely dissolved and ultrafine dendrites of austenite with submicroscopic M{sub 23}C{sub 6} carbides precipitation are formed in the melted zone. The austenite in the melted zone has a high tempering stability. The corrosion resistance of the laser surface-melted steels is significantly improved due to the dissolution of carbides and the increase of the alloying elements in the solid solution as well as the large amount of austenite.

Effect of Laser Power on Metallurgical, Mechanical and Tribological Characteristics of Hardfaced Surfaces of Nickel-Based Alloy

Science.gov (United States)

Gnanasekaran, S.; Padmanaban, G.; Balasubramanian, V.

2017-12-01

In this present work, nickel based alloy was deposited on 316 LN austenitic stainless steel (ASS) by a laser hardfacing technique to investigate the influence of laser power on macrostructure, microstructure, microhardness, dilution and wear characteristics. The laser power varied from 1.1 to 1.9 kW. The phase constitution, microstructure and microhardness were examined by optical microscope, scanning electron microscopy, energy dispersion spectroscopy and Vickers microhardness tester. The wear characteristics of the hardfaced surfaces and substrate were evaluated at room temperature (RT) under dry sliding wear condition (pin-on-disc). The outcome demonstrates that as the laser power increases, dilution increases and hardness of the deposit decreases. This is because excess heat melts more volume of substrate material and increases the dilution; subsequently it decreases the hardness of the deposit. The microstructure of the deposit is characterized by Ni-rich carbide, boride and silicide.

Microstructure and antibacterial properties of microwave plasma nitrided layers on biomedical stainless steels

International Nuclear Information System (INIS)

Lin, Li-Hsiang; Chen, Shih-Chung; Wu, Ching-Zong; Hung, Jing-Ming; Ou, Keng-Liang

2011-01-01

Nitriding of AISI 303 austenitic stainless steel using microwave plasma system at various temperatures was conducted in the present study. The nitrided layers were characterized via scanning electron microscopy, glancing angle X-ray diffraction, transmission electron microscopy and Vickers microhardness tester. The antibacterial properties of this nitrided layer were evaluated. During nitriding treatment between 350 deg. C and 550 deg. C, the phase transformation sequence on the nitrided layers of the alloys was found to be γ → (γ + γ N ) → (γ + α + CrN). The analytical results revealed that the surface hardness of AISI 303 stainless steel could be enhanced with the formation of γ N phase in nitriding process. Antibacterial test also demonstrated the nitrided layer processed the excellent antibacterial properties. The enhanced surface hardness and antibacterial properties make the nitrided AISI 303 austenitic stainless steel to be one of the essential materials in the biomedical applications.

The Effect of Diode Laser Treatment for Root Canal Disinfection on Fracture Resistance and Micro-hardness of the Tooth

International Nuclear Information System (INIS)

Elmiligy, H.H; Diab, A.H.; Sabet, N.E.; Saafan, A.M.

2014-01-01

This study evaluated the effect of diode laser treatment for root canal disinfection on fracture resistance and micro-hardness of the tooth. Sixty freshly extracted mandibular and maxillary premolars were accessed under coolant then root canals were flared up to apical preparation size 40 MFA coupled with 5.25% NaOCl as an irrigant. Teeth were divided into two groups, control group (group I) and lased group (group II) that was lased by diode laser with average power 2 w through fibrooptic into the canal 2 mm shorter than the apex. Each tooth was embedded in acrylic block, and then subjected to the fracture resistance test. Each root was then sectioned transversely and polished to record dentin Vickers hardness. Data was analysed with student t-test then with linear regression test. The Lased samples presented a significantly higher resistance to fracture than unlased samples. There was no statistically significant differences found between Vickers hardness (HV) of lased and unlased samples and there was no relation between fracture resistance and microhardness. Diode laser (980 nm) treatment had no adverse effect on dentin microhardness, also it increased the fracture resistance of dentin. Diode laser (980 nm) treatment could attain better function ability and maintenance of tooth after endodontic treatment.

Quality assurance in design: policy adopted by Vickers Barrow Engineering Works

International Nuclear Information System (INIS)

Aubrey, J.H.

1976-01-01

The quality assurance system operated by the Vickers Barrow Engineering Works is described, with special reference to the design of the reactor shield and above core structure for the first commercial fast reactor. Section headings are: introduction; what is quality assurance of design; attitude of designer; design discipline; customers attitude; Engineering Company system; future application of Design Quality Assurance Record system. (U.K.)

Estimation of the Ultimate Tensile Strength of Steel from Its HB and HV Hardness Numbers and Coercive Force

Science.gov (United States)

Sandomirskii, S. G.

2017-11-01

A formula is derived to accurately describe the tabulated relation between the Brinell ( HB) and Vickers ( HV) hardnesses of steel over the entire range of their possible variation. This formula and the formulas describing the relation between the HB hardness of chromium-molybdenum and chromium-nickel steels and their ultimate tensile strength σu are used to analyze the change in σu of 38KhNM steel upon quenching and tempering. The data that reveal a relation between σu of 38KhNM steel and its coercive force are obtained.

Effect of heat-treatment on the hardness and mechanical properties of Boron Alloyed Steel

Directory of Open Access Journals (Sweden)

bin Khiyon Mohammad Raffik

2017-01-01

Full Text Available In an automotive industry, hot stamped, die quenched structural components have been widely used to provide extra protection against crash intrusion. Boron alloyed steel exhibit limited ductility, but it also promotes improvement in impact performance. This study analyzed the effect of cooling rate on the hardness and energy absorption. Self-quenched specimens were heated to 850°C and cooled in air of room temperature, water at room temperature and cold water. Vickers hardness test and tensile test was then carried out to analyze the effect of different quenching rate. Self-quenched specimens were compared to the properties of the die-quenched specimens obtained from commercial automobile body. Result shows that boron steel with the highest cooling rate has the highest value of hardness but low in strength.

Assessment of the hardness of different orthodontic wires and brackets produced by metal injection molding and conventional methods.

Science.gov (United States)

Alavi, Shiva; Kachuie, Marzie

2017-01-01

This study was conducted to assess the hardness of orthodontic brackets produced by metal injection molding (MIM) and conventional methods and different orthodontic wires (stainless steel, nickel-titanium [Ni-Ti], and beta-titanium alloys) for better clinical results. A total of 15 specimens from each brand of orthodontic brackets and wires were examined. The brackets (Elite Opti-Mim which is produced by MIM process and Ultratrimm which is produced by conventional brazing method) and the wires (stainless steel, Ni-Ti, and beta-titanium) were embedded in epoxy resin, followed by grinding, polishing, and coating. Then, X-ray energy dispersive spectroscopy (EDS) microanalysis was applied to assess their elemental composition. The same specimen surfaces were repolished and used for Vickers microhardness assessment. Hardness was statistically analyzed with Kruskal-Wallis test, followed by Mann-Whitney test at the 0.05 level of significance. The X-ray EDS analysis revealed different ferrous or co-based alloys in each bracket. The maximum mean hardness values of the wires were achieved for stainless steel (SS) (529.85 Vickers hardness [VHN]) versus the minimum values for beta-titanium (334.65 VHN). Among the brackets, Elite Opti-Mim exhibited significantly higher VHN values (262.66 VHN) compared to Ultratrimm (206.59 VHN). VHN values of wire alloys were significantly higher than those of the brackets. MIM orthodontic brackets exhibited hardness values much lower than those of SS orthodontic archwires and were more compatible with NiTi and beta-titanium archwires. A wide range of microhardness values has been reported for conventional orthodontic brackets and it should be considered that the manufacturing method might be only one of the factors affecting the mechanical properties of orthodontic brackets including hardness.

Analysis of surface hardness of artificially aged resin composites

Directory of Open Access Journals (Sweden)

Denise Cremonezzi Tornavoi

2012-02-01

Full Text Available This study evaluated the effect of artificially accelerated aging (AAA on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05, ANOVA and Tukey test (p < 0.05. With regard to hardness (F = 86.74, p < 0.0001 the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53. In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002. It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

HIV impact on women: gender difference among late testers and advanced HIV infection

Science.gov (United States)

Sukmawati, N. M. D. D.; Merati, T. P.; Somia, A.; Utama, S.; Gayatri, Y.

2018-03-01

This study reported the effect of gender difference on HIV seropositive late testers or advanced infection. A retrospective cohort study of newly diagnosed HIV seropositive based on adatabase in the main referral hospital in Denpasar, Bali, Indonesia from 2004 – 2016. Women and man were categorized as late testers (CD4 ≤ 200 cells/uL and/or AIDS diagnosis ≤ 12 months from first HIV test date). Non-late testers (CD4 > 200 cells/uL and/or no AIDS diagnosis during study period or diagnosis of AIDS >12 months from HIV diagnosis), of reproductive age (13 – 49 years old), and not of reproductive age (>49 years old). Logistic regression was used to estimate risk and its statistical significance. The model consists of gender and age correctly classified 83.5% of cases. Women were almost two times more likely to present as non-late testers compared to men, and reproductive age of 15 – 49 years were 1.5 times more likely to present as non-late testers compared to those with age > 49 years. Women affected by HIV almost in equal as for men. Women and those within reproductive age were more likely to present before the advanced stage compared to men and those aged > 49 years.

Synthesis and mechanical properties of bulk Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} alloy fabricated by consolidation of mechanically alloyed amorphous powders

Energy Technology Data Exchange (ETDEWEB)

Wang, Xinfu; Wang, Kun; Li, Zhendong; Wang, Xingfu; Wang, Dan; Han, Fusheng, E-mail: fshan@issp.ac.cn

2015-05-25

Graphical abstract: Different regions indentation morphologies under 50 g load consolidated at 723 K (left), nanohardness of the Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} alloy as a function consolidation temperature (right). It can be seen from the above figures that the consolidated sample presents white regions, and the microhardness in the white regions is a little lower than the matrix, which could be caused by the difference of the chemical composition and chemical bonding forces between them. Interestingly, the cracks were formed around the indentation periphery in the white regions, which are not shown in the matrix. The nanohardness of the bulk composites increased from 11.16 to 13.27 GPa with the consolidation temperature increasing, mechanical softening was also found in the present alloys. - Highlights: • Bulk amorphous–nanocrystalline Al-based alloys were prepared by HPS process. • The Vickers microhardness of bulk samples is in the range of 945–1177HV0.1. • The nanohardness agrees well with the Vickers hardness testing results. - Abstract: Mechanically alloyed amorphous Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} (at.%) alloy powder was consolidated by high-pressure sintering process. The influence of the consolidation temperature on the structure and mechanical properties of the consolidated bulk alloys was examined by X-ray diffraction (XRD), Optical microscopy (OM), Scanning electron microscopy (SEM), Vickers Hardness Tester and Nano Indenter. Structural investigations of the bulk materials revealed that most of the amorphous structure was retained after consolidation at 623 K, however, compaction at 723 K and 823 K caused crystallization of the amorphous phase with the appearance of white regions. The results also indicate that application of high pressure affected the crystallization products of the present alloy. Micro mechanical analysis showed that the microhardness of the bulk composites increased from 945HV{sub 0.1} to 1177HV

Mechanical properties of brazing joints of alumina dispersion strengthened copper to 316 stainless steel for fusion reactor divertor

International Nuclear Information System (INIS)

Nishi, Hiroshi; Araki, Toshiaki.

1994-01-01

Brazing of alumina dispersion strengthened copper to 316 stainless steel was carried out with the brazing parameters such as brazing alloy, clearance and time to investigate the influence of brazing conditions on the joint strength. Tensile and Charpy impact tests of the joint specimens were performed to evaluate their strength. Microstructure and hardness of the brazed zone were examined with an optical microscope and a Vickers hardness tester. The excellent brazing joint strength was achieved with BAu-2 brazing alloy. The tensile strength of the joint with the brazing clearance of 0.2mm and the brazing time of 300s was as large as that of the diffusion bonding joint. However, Charpy absorbed energy of the brazing was lower than that of the diffusion bonding. Alumina dispersion strengthened copper remelted near the brazed zone because of diffusion of the brazing alloy, and the specimens fractured at the remelted zone. The brazed zone included many voids, which caused a scattering of the strength. (author)

Laser cladding Ni-base composite coating on titanium alloy with pre-placed B4C+NiCoCrAlY

International Nuclear Information System (INIS)

Qingwu Meng; Lin Geng; Zhenzhu Zheng

2005-01-01

Using a CO 2 laser, a process of cladding Ni-base composite coating on Ti6Al4V with pre-placed B 4 C and NiCoCrAlY was studied. A good metallurgical bonding coating without cracks and pores was obtained in reasonable ratio of components and low energy laser process. Morphology and microstructure of the coating were analyzed with OM, XRD, SEM and EDS. It is certain that there was a reaction between B 4 C and Ti during in-situ producing TiB 2 and TiC. The Ni-base composite coating is strengthened with TiB 2 and TiC reinforcement phases. Vickers hardness tester measured that the average microhardness of the coating is HV1200 and it is 3.5 times of the Ti6Al4V substrate. The high hard coating containing several reinforcement phases greatly enhances wear resistance of titanium alloy. (orig.)

Preparation of anti-adhesion surfaces on aluminium substrates of rubber plastic moulds using a coupling method of liquid plasma and electrochemical machining

Science.gov (United States)

Meng, Jianbing; Dong, Xiaojuan; Wei, Xiuting; Yin, Zhanmin

2014-03-01

Hard anti-adhesion surfaces, with low roughness and wear resistance, on aluminium substrates of rubber plastic moulds were fabricated via a new coupling method of liquid plasma and electrochemical machining. With the aid of liquid plasma thermal polishing and electrochemical anodic dissolution, micro/nano-scale binary structures were prepared as the base of the anti-adhesion surfaces. The anti-adhesion behaviours of the resulting aluminium surfaces were analysed by a surface roughness measuring instrument, a scanning electron microscope (SEM), a Fourier-transform infrared spectrophotometer (FTIR), an X-ray diffractometer (XRD), an optical contact angle meter, a digital Vickers micro-hardness (Hv) tester, and electronic universal testing. The results show that, after the liquid plasma and electrochemical machining, micro/nano-scale binary structures composed of micro-scale pits and nano-scale elongated boss structures were present on the sample surfaces. As a result, the anti-adhesion surfaces fabricated by the above coupling method have good anti-adhesion properties, better wear resistance and lower roughness.

Preparation of anti-adhesion surfaces on aluminium substrates of rubber plastic moulds using a coupling method of liquid plasma and electrochemical machining

Directory of Open Access Journals (Sweden)

Jianbing Meng

2014-02-01

Full Text Available Hard anti-adhesion surfaces, with low roughness and wear resistance, on aluminium substrates of rubber plastic moulds were fabricated via a new coupling method of liquid plasma and electrochemical machining. With the aid of liquid plasma thermal polishing and electrochemical anodic dissolution, micro/nano-scale binary structures were prepared as the base of the anti-adhesion surfaces. The anti-adhesion behaviours of the resulting aluminium surfaces were analysed by a surface roughness measuring instrument, a scanning electron microscope (SEM, a Fourier-transform infrared spectrophotometer (FTIR, an X-ray diffractometer (XRD, an optical contact angle meter, a digital Vickers micro-hardness (Hv tester, and electronic universal testing. The results show that, after the liquid plasma and electrochemical machining, micro/nano-scale binary structures composed of micro-scale pits and nano-scale elongated boss structures were present on the sample surfaces. As a result, the anti-adhesion surfaces fabricated by the above coupling method have good anti-adhesion properties, better wear resistance and lower roughness.

Preparation of anti-adhesion surfaces on aluminium substrates of rubber plastic moulds using a coupling method of liquid plasma and electrochemical machining

Energy Technology Data Exchange (ETDEWEB)

Meng, Jianbing, E-mail: jianbingmeng@126.com; Dong, Xiaojuan; Wei, Xiuting; Yin, Zhanmin [School of Mechanical Engineering, Shandong University of Technology, Zibo, 255049 (China)

2014-03-15

Hard anti-adhesion surfaces, with low roughness and wear resistance, on aluminium substrates of rubber plastic moulds were fabricated via a new coupling method of liquid plasma and electrochemical machining. With the aid of liquid plasma thermal polishing and electrochemical anodic dissolution, micro/nano-scale binary structures were prepared as the base of the anti-adhesion surfaces. The anti-adhesion behaviours of the resulting aluminium surfaces were analysed by a surface roughness measuring instrument, a scanning electron microscope (SEM), a Fourier-transform infrared spectrophotometer (FTIR), an X-ray diffractometer (XRD), an optical contact angle meter, a digital Vickers micro-hardness (Hv) tester, and electronic universal testing. The results show that, after the liquid plasma and electrochemical machining, micro/nano-scale binary structures composed of micro-scale pits and nano-scale elongated boss structures were present on the sample surfaces. As a result, the anti-adhesion surfaces fabricated by the above coupling method have good anti-adhesion properties, better wear resistance and lower roughness.

The effect of surface nanocrystallization on plasma nitriding behaviour of AISI 4140 steel

International Nuclear Information System (INIS)

Li Yang; Wang Liang; Zhang Dandan; Shen Lie

2010-01-01

A plastic deformation surface layer with nanocrystalline grains was produced on AISI 4140 steel by means of surface mechanical attrition treatment (SMAT). Plasma nitriding of SMAT and un-SMAT AISI 4140 steel was carried out by a low-frequency pulse excited plasma unit. A series of nitriding experiments has been conducted at temperatures ranging from 380 to 500 deg. C for 8 h in an NH 3 gas. The samples were characterized using X-ray diffraction, scanning electron microscopy, optical microscopy and Vickers microhardness tester. The results showed that a much thicker compound layer with higher hardness was obtained for the SMAT samples when compared with un-SMAT samples after nitriding at the low temperature. In particular, plasma nitriding SMAT AISI 4140 steel at 380 deg. C for 8 h can produced a compound layer of 2.5 μm thickness with very high hardness on the surface, which is similar to un-SMAT samples were plasma nitrided at approximately 430 deg. C within the same time.

The effect of surface nanocrystallization on plasma nitriding behaviour of AISI 4140 steel

Science.gov (United States)

Li, Yang; Wang, Liang; Zhang, Dandan; Shen, Lie

2010-11-01

A plastic deformation surface layer with nanocrystalline grains was produced on AISI 4140 steel by means of surface mechanical attrition treatment (SMAT). Plasma nitriding of SMAT and un-SMAT AISI 4140 steel was carried out by a low-frequency pulse excited plasma unit. A series of nitriding experiments has been conducted at temperatures ranging from 380 to 500 °C for 8 h in an NH 3 gas. The samples were characterized using X-ray diffraction, scanning electron microscopy, optical microscopy and Vickers microhardness tester. The results showed that a much thicker compound layer with higher hardness was obtained for the SMAT samples when compared with un-SMAT samples after nitriding at the low temperature. In particular, plasma nitriding SMAT AISI 4140 steel at 380 °C for 8 h can produced a compound layer of 2.5 μm thickness with very high hardness on the surface, which is similar to un-SMAT samples were plasma nitrided at approximately 430 °C within the same time.

Surface nanocrystallization by surface mechanical attrition treatment and its effect on structure and properties of plasma nitrided AISI 321 stainless steel

Energy Technology Data Exchange (ETDEWEB)

Lin Yimin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: linyimin_2001@yahoo.com.cn; Lu Jian [LASMIS, University of Technology of Troyes, 10000 Troyes (France); Wang Liping [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Xu Tao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Xue Qunji [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China)]. E-mail: qjxue@ns.lzb.ac.cn

2006-12-15

A plastic deformation surface layer with nanocrystalline grains was produced on AISI 321 austenitic stainless steel by means of surface mechanical attrition treatment (SMAT). Low-temperature nitriding of SMAT and un-SMAT AISI 321 stainless steel was carried out in pulsed-DC glow discharge. The effect of SMAT pretreatment on the microstructure and properties of the stainless steel were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Vickers hardness tester and UMT-2MT tribometer. The results show that the plasma nitriding of AISI 321 steel can be enhanced considerably by means of SMAT process before nitriding, and a much thicker nitrogen diffusion layer with higher hardness was obtained for the SMAT samples when compared with un-SMAT samples. In addition, the wear resistance and load capacity of the nitrided layers on the SMAT samples was much higher than that of the un-SMAT samples due to the thicker S phase case and the gradient nitrogen diffusion layer.

Effect of sintering atmosphere on the hardness of ThO_2

International Nuclear Information System (INIS)

Baena, Angela; Cardinaels, Thomas; Van Eyken, Jelle; Puzzolante, Jean Louis; Binnemans, Koen; Verwerft, Marc

2016-01-01

The hardness and toughness of ThO_2 sintered under reducing and oxidizing conditions has been investigated and, quite unexpectedly, a significant difference in hardness was observed for the entire range of porosities studied. Reducing conditions systematically yielded higher hardness values than oxidizing conditions. Extrapolated to zero porosity, the hardness for ThO_2 is H_0 = 10.5 ± 0.3 GPa for oxidizing conditions and H_0 = 12.4 ± 0.7 GPa for reducing conditions. Toughness values have been derived from Vickers indentations; differences in toughness were insignificant and only a single value is proposed: K_I_C = 0.97 ± 0.12 MPa √m. The difference in hardness is attributed to the presence of point defects, also acting as color centers and causing grey coloration of ThO_2 sintered under reducing conditions. Furthermore, and of interest for nuclear fuel production, is the finding that ThO_2 sintered under reducing conditions is significantly easier to grind compared to material sintered under oxidizing conditions. - Highlights: • Reducing sintering conditions increase the hardness of polycrystalline ThO_2. • Systematic series of hardness versus porosity of ThO_2 were obtained. • Reducing sintering conditions improve grinding of ThO_2.

Tooth enamel surface micro-hardness with dual species Streptococcus biofilm after exposure to Java turmeric (Curcuma xanthorrhiza Roxb.) extract

Science.gov (United States)

Isjwara, F. R. G.; Hasanah, S. N.; Utami, Sri; Suniarti, D. F.

2017-08-01

Streptococcus biofilm on tooth surfaces can decrease mouth environment pH, thus causing enamel demineralization that can lead to dental caries. Java Turmeric extract has excellent antibacterial effects and can maintain S. mutans biofilm pH at neutral levels for 4 hours. To analyze the effect of Java Turmeric extract on tooth enamel micro-hardness, the Java Turmeric extract was added on enamel tooth samples with Streptococcus dual species biofilm (S. sanguinis and S. mutans). The micro-hardness of enamel was measured by Knoop Hardness Tester. Results showed that Curcuma xanthorrhiza Roxb. could not maintain tooth enamel surface micro-hardness. It is concluded that Java Turmeric extract ethanol could not inhibit the hardness of enamel with Streptococcus dual species biofilm.

Hand-Drawn Resistors and a Simple Tester Using a Light-Emitting Diode

Science.gov (United States)

Kamata, Masahiro; Abe, Mayumi

2012-01-01

A thick line drawn on a sheet of paper with a 6B pencil is electrically conductive and its resistance can be roughly estimated using a simple tester made of a light-emitting diode (LED) and a lithium coin-type cell. Using this hand-drawn resistor and the LED tester, we developed teaching materials that help students to understand how electrical…

A study on the high velocity impact behavior of titanium alloy by PVD method

International Nuclear Information System (INIS)

Sohn, Se Won; Lee, Doo Sung; Hong, Sung Hee

2001-01-01

In order to investigate the fracture behaviors(penetration modes) and resistance to penetration during ballistic impact of titanium alloy laminates and nitrified titanium alloy laminates which were treated by PVD(Physical Vapor Deposition) method, ballistic tests were conducted. Evaporation, sputtering, and ion plating are three kinds of PVD method. In this research, ion plating was used to achieve higher surface hardness and surface hardness test were conducted using a micro Vicker's hardness tester. Resistance to penetration is determined by the protection ballistic limit(V 50 ), a statistical velocity with 50% probability for complete penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are respectfully observed at and above ballistic limit velocities, as a result of V 50 test and Projectile Through Plates(PTP) test methods. PTP tests were conducted with 0 .deg. obliquity at room temperature using 5.56mm ball projectile. V 50 tests with 0 .deg. obliquity at room temperature were conducted with projectiles that were able to achieve near or complete penetration during PTP tests. Surface hardness, resistance to penetration, and penetration modes of titanium alloy laminates are compared to those of nitrified titanium alloy laminates

Evaluation of disintegration properties of orally rapidly disintegrating tablets using a novel disintegration tester.

Science.gov (United States)

Kondo, Keita; Niwa, Toshiyuki; Danjo, Kazumi

2012-01-01

This report describes a new disintegration tester that can determine not only the disintegration time of orally rapidly disintegrating tablets (ODT), but also the disintegration behavior and mechanism. Using the tester, the disintegration properties of the tablets prepared in a previous study were examined. The purpose of this study is to confirm the utility of the tester as an instrument for evaluating the disintegration properties of ODT and determine relations among time, behavior and mechanism of the disintegration. Results demonstrated that in vitro disintegration time in the tester is similar to that in the commercial disintegration tester for ODT and is highly correlated with oral disintegration time. Observations of disintegration process revealed that a difference in disintegration behavior between tablets compressed at 50-75 MPa and 100 MPa; the disintegration behavior of the tablets were designated immediate disintegrating type and gradual disintegrating type, respectively. The dynamic swelling profile and water absorption profile indicated that the disintegration mechanism of the tablets involved wicking action induced by swelling of the disintegrant; the disintegration time was closely related to the initial rates of swelling and water absorption. Furthermore, the mechanism of water absorption of tablets compressed at 50-75 MPa and 100 MPa shows anomalous diffusion and case-II transport, respectively. The shift in this mechanism is consistent with differences in disintegration time and behavior between the tablets. These findings suggest that information on disintegration properties obtained by our tester is useful for understanding of disintegration phenomena of ODT.

The reliability of the newly developed bending tester for the measurement of flexural rigidity of textile materials

Science.gov (United States)

Haji Musa, A. Binti; Malengier, B.; Van Langenhove, L.; Stevens, C.

2017-10-01

A new automated bending tester was developed in Ghent University, Belgium to reduce the human interference in the bending measurement. This paper reports the investigations made on the tester in order to confirm the reliability of its measurement. For that, 11 types of fabrics with different construction parameters were tested for their bending length and flexural rigidity using the new bending tester and the results were compared with that of the standard or manual bending tester, which were conducted in accordance with BS 3356:1990 standard method. Statistical analysis confirms that both measurements are strongly correlated with Pearson’s R≥ 0.90 for all the measurements made. It means that the results from the new automated tester show good correlations with the standard measurement. Nevertheless, this prototype version of the new tester still needs to be adjusted to optimise the functionality of it and further investigations should be done to justify the robustness of the results.

Vickers Attenuator. Volume 3C(VA) - Technical appraisal. Consultants' 1983 report

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

A report is given by a team of Consultants on the estimated cost of converting wave energy to electrical energy by a 2 GW array of Vickers Attenuator wave energy devices and delivering this to a sub-station on the west coast of Skye. Comparisons of the estimates made by the team developing the concept are presented and discrepancies discussed. A detailed engineering assessment is given.

Interference of apex locator, pulp tester and diathermy on pacemaker function

OpenAIRE

Narayanan Sriman; V Prabhakar; J S Bhuvaneswaran; N Subha

2015-01-01

Aim: The purpose of this study was to evaluate the effects of three electronic apex locators (EAL), electric pulp tester (EPT) and diathermy on pacemaker function in vitro. Materials and Methods: Three EALs: Root ZX (J. Morita Co., Tustin, CA, U.S.A.), Propex (Dentsply), Mini Apex locator (SybronEndo, Anaheim, CA, USA), EPT (Parkell pulp vitality tester Farmingdale, NY, USA) and Diathermy (Neomed 250 B) were tested for any interference with one pacemaker (A medtronic kappa KVDD901-serial ...

Characterisation of weldment hardness, impact energy and microstructure in API X65 steel

International Nuclear Information System (INIS)

Hashemi, S.H.; Mohammadyani, D.

2012-01-01

The variation of microstructure and mechanical properties in various sub-zones of double submerged arc welded line pipe steel of grade API X65 was investigated. Instrumented Charpy V-notch tests and Vickers hardness experiments were conducted on the fusion zone, base metal and heat affected zone of the weld joint in 14.3 mm thick, 1219 mm outside diameter spiral pipeline. The lowest impact energy and the highest hardness level (160J and 218 HV, respectively) were recorded in the fusion zone. The low energy and high hardness characteristics of the seam weld can be attributed to its cast microstructure and the presence of grain boundary phases (such as proeutectoid ferrite), confirmed by standard metallographic observation. Despite this, service requirements set by the API 5L industry code (minimum impact energy of 73J, maximum hard spots of 350 HV) were fulfilled by the tested steel. Highlights: ► Experimental study of API X65 steel microstructure. ► Analysis of the relationship between X65 steel microstructure and hardness. ► Analysis of the relationship between X65 steel microstructure and impact energy. ► Presentation of detailed technical information on DSA welding in spiral pipes.

Effect of sintering atmosphere on the hardness of ThO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Baena, Angela; Cardinaels, Thomas [Belgian Nuclear Research Centre (SCK-CEN), Institute for Nuclear Materials Science, Fuel Materials Group, Boeretang 200, B-2400, Mol (Belgium); KU Leuven, Department of Chemistry, Celestijnenlaan 200F, P.O. Box 2404, B-3001, Heverlee (Belgium); Van Eyken, Jelle; Puzzolante, Jean Louis [Belgian Nuclear Research Centre (SCK-CEN), Institute for Nuclear Materials Science, Fuel Materials Group, Boeretang 200, B-2400, Mol (Belgium); Binnemans, Koen [KU Leuven, Department of Chemistry, Celestijnenlaan 200F, P.O. Box 2404, B-3001, Heverlee (Belgium); Verwerft, Marc, E-mail: marc.verwerft@sckcen.be [Belgian Nuclear Research Centre (SCK-CEN), Institute for Nuclear Materials Science, Fuel Materials Group, Boeretang 200, B-2400, Mol (Belgium)

2016-08-15

The hardness and toughness of ThO{sub 2} sintered under reducing and oxidizing conditions has been investigated and, quite unexpectedly, a significant difference in hardness was observed for the entire range of porosities studied. Reducing conditions systematically yielded higher hardness values than oxidizing conditions. Extrapolated to zero porosity, the hardness for ThO{sub 2} is H{sub 0} = 10.5 ± 0.3 GPa for oxidizing conditions and H{sub 0} = 12.4 ± 0.7 GPa for reducing conditions. Toughness values have been derived from Vickers indentations; differences in toughness were insignificant and only a single value is proposed: K{sub IC} = 0.97 ± 0.12 MPa √m. The difference in hardness is attributed to the presence of point defects, also acting as color centers and causing grey coloration of ThO{sub 2} sintered under reducing conditions. Furthermore, and of interest for nuclear fuel production, is the finding that ThO{sub 2} sintered under reducing conditions is significantly easier to grind compared to material sintered under oxidizing conditions. - Highlights: • Reducing sintering conditions increase the hardness of polycrystalline ThO{sub 2}. • Systematic series of hardness versus porosity of ThO{sub 2} were obtained. • Reducing sintering conditions improve grinding of ThO{sub 2}.

High inter-tester reliability of the new mobility score in patients with hip fracture

DEFF Research Database (Denmark)

Kristensen, M.T.; Bandholm, T.; Foss, N.B.

2008-01-01

OBJECTIVE: To assess the inter-tester reliability of the New Mobility Score in patients with acute hip fracture. DESIGN: An inter-tester reliability study. SUBJECTS: Forty-eight consecutive patients with acute hip fracture at a median age of 84 (interquartile range, 76-89) years; 40 admitted from...

Small-Bolt Torque-Tension Tester

Science.gov (United States)

Posey, Alan J.

2009-01-01

The device described here measures the torque-tension relationship for fasteners as small as #0. The small-bolt tester consists of a plate of high-strength steel into which three miniature load cells are recessed. The depth of the recess is sized so that the three load cells can be shimmed, the optimum height depending upon the test hardware. The three miniature load cells are arranged in an equilateral triangular configuration with the test bolt aligned with the centroid of the three. This is a kinematic arrangement.

Enhanced Master Controller Unit Tester

Science.gov (United States)

Benson, Patricia; Johnson, Yvette; Johnson, Brian; Williams, Philip; Burton, Geoffrey; McCoy, Anthony

2007-01-01

The Enhanced Master Controller Unit Tester (EMUT) software is a tool for development and testing of software for a master controller (MC) flight computer. The primary function of the EMUT software is to simulate interfaces between the MC computer and external analog and digital circuitry (including other computers) in a rack of equipment to be used in scientific experiments. The simulations span the range of nominal, off-nominal, and erroneous operational conditions, enabling the testing of MC software before all the equipment becomes available.

16 CFR Figure 3 to Subpart A of... - Flooring Radiant Tester Schematic Side Elevation

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flooring Radiant Tester Schematic Side Elevation 3 Figure 3 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION.... 1209, Subpt. A, Fig. 3 Figure 3 to Subpart A of Part 1209—Flooring Radiant Tester Schematic Side...

Effects of deposited nuclear and electronic energy on the hardness of R7T7-type containment glass

Energy Technology Data Exchange (ETDEWEB)

Peuget, S. [Commissariat a l' Energie Atomique, CEA Marcoule, DEN/DTCD/SECM/LMPA, Batiment 166, BP 17171, F-30207 Bagnols-sur-Ceze Cedex (France)]. E-mail: sylvain.peuget@cea.fr; Noel, P.-Y. [Commissariat a l' Energie Atomique, CEA Marcoule, DEN/DTCD/SECM/LMPA, Batiment 166, BP 17171, F-30207 Bagnols-sur-Ceze Cedex (France); Loubet, J.-L. [Laboratoire de Tribologie et Dynamique des Systemes, UMR CNRS 5513, Ecole Centrale de Lyon 36, avenue Guy de Collongue, 69134 Ecully Cedex (France); Pavan, S. [Laboratoire de Tribologie et Dynamique des Systemes, UMR CNRS 5513, Ecole Centrale de Lyon 36, avenue Guy de Collongue, 69134 Ecully Cedex (France); Nivet, P. [Commissariat a l' Energie Atomique, CEA Marcoule, DEN/DTCD/SECM/LMPA, Batiment 166, BP 17171, F-30207 Bagnols-sur-Ceze Cedex (France); Chenet, A. [Commissariat a l' Energie Atomique, CEA Marcoule, DEN/DTCD/SECM/LMPA, Batiment 166, BP 17171, F-30207 Bagnols-sur-Ceze Cedex (France)

2006-05-15

The effects of elastic and inelastic interactions induced by cumulative alpha decay on the hardness of R7T7-type nuclear containment glass were investigated on actinide-doped glass specimens and by external irradiation of inactive glass by light and heavy ions. Vickers microindentation and nanoindentation hardness measurements showed that in the deposited energy range investigated (below 3 x 10{sup 22} keV/cm{sup 3}) inelastic effects have no influence on the plastic response of the glass. Conversely, identical hardness variations versus the nuclear energy deposited in the material were observed on curium-doped glass and on glass irradiated by ion bombardment. The observed hardness variation stabilized after the deposited energy reached about 3 x 10{sup 2} keV{sub nucl}/cm{sup 3}. These findings indicate that the change in the plastic response of the glass is a consequence of ballistic effects.

Effect of Heating Time on Hardness Properties of Laser Clad Gray Cast Iron Surface

Science.gov (United States)

Norhafzan, B.; Aqida, S. N.; Mifthal, F.; Zulhishamuddin, A. R.; Ismail, I.

2018-03-01

This paper presents effect of heating time on cladded gray cast iron. In this study, the effect of heating time on cladded gray cast iron and melted gray cast iron were analysed. The gray cast iron sample were added with mixed Mo-Cr powder using laser cladding technique. The mixed Mo and Cr powder was pre-placed on gray cast iron surface. Modified layer were sectioned using diamond blade cutter and polish using SiC abrasive paper before heated. Sample was heated in furnace for 15, 30 and 45 minutes at 650 °C and cool down in room temperature. Metallographic study was conduct using inverted microscope while surface hardness properties were tested using Wilson hardness test with Vickers scale. Results for metallographic study showed graphite flakes within matrix of pearlite. The surface hardness for modified layer decreased when increased heating time process. These findings are significant to structure stability of laser cladded gray cast iron with different heating times.

Colour of Tester Effects on Children's Expressed Attitudes.

Science.gov (United States)

Thomas, K. C.

1978-01-01

Discusses a study of student attitudes, preferences, and stereotyping among White Britons and West Indian students in an English secondary school. Findings indicated that factors such as the race of the tester influenced the test situation. For journal availability, see SO 506 785. (DB)

Effect of Repeated Microwave Disinfection on Surface Hardness and Dimensional Accuracy of Two Dental Stone Materials

Directory of Open Access Journals (Sweden)

Mahmood Robati Anaraki

2015-01-01

Full Text Available There is controversial evidence in relation to the effect of microwave on mechanical properties of stone casts. The present study was designed to evaluate the effect of repeated microwave disinfection on surface hardness and dimensional accuracy of dental stone. In this in vitro study, 48 cylindrical stone samples were prepared using two products of type IV stone to assess surface hardness and 48 impressions were taken from a model and poured by these stones to assess the dimensional accuracy. The evaluation of the samples was carried out consequently by a micro-hardness tester and a digital caliper after the stone samples were exposed to 7 consecutive rounds of 900 watts (W microwave irradiation for five minutes each time after cooling. Data were analyzed by t-test and ANOVA. According to the obtained results, multiple disinfections of the stone casts by microwave do not negatively affect their surface hardness and dimensional accuracy.   Key words: Dental stone; Dimensional accuracy; Hardness; Microwave

Computer-assisted acoustic emission analysis in alternating current magnetization and hardness testing of reactor pressure vessel steels

International Nuclear Information System (INIS)

Blochwitz, M.; Kretzschmar, F.; Rattke, R.

1985-01-01

Non-destructive determination of material characteristics such as nilductility transition temperature is of high importance in component monitoring during long-term operation. An attempt has been made to obtain characteristics correlating with mechanico-technological material characteristics by both acoustic resonance through magnetization (ARDM) and acoustic emission analysis in Vickers hardness tests. Taking into account the excitation mechanism of acoustic emission generation, which has a quasistationary stochastic character in a.c. magnetization and a transient nature in hardness testing, a microcomputerized device has been constructed for frequency analysis of the body sound level in ARDM evaluation and for measuring the pulse sum and/or pulse rate during indentation of the test specimen in hardness evaluation. Prerequisite for evaluating the measured values is the knowledge of the frequency dependence of the sensors and the instrument system. The results obtained are presented. (author)

Phase formation kinetics, hardness and magnetocaloric effect of sub-rapidly solidified LaFe11.6Si1.4 plates during isothermal annealing

Science.gov (United States)

Dai, Yuting; Xu, Zhishuai; Luo, Zhiping; Han, Ke; Zhai, Qijie; Zheng, Hongxing

2018-05-01

High-temperature phase transition behavior and intrinsic brittleness of NaZn13-type τ1 phase in La-Fe-Si magnetocaloric materials are two key problems from the viewpoint of materials production and practical applications. In the present work, the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation was introduced to quantitatively characterize the formation kinetics of τ1 phase in sub-rapidly solidified LaFe11.6Si1.4 plates during the isothermal annealing process. Avrami index was estimated to be 0.43 (∼0.5), which suggests that the formation of τ1 phase is in a diffusion-controlled one-dimensional growth mode. Meanwhile, it is found that the Vickers hardness as a function of annealing time for sub-rapidly solidified plates also agrees well with the JMAK equation. The Vickers hardness of τ1 phase was estimated to be about 754. Under a magnetic field change of 30 kOe, the maximum magnetic entropy change was about 22.31 J/(kg·K) for plates annealed at 1323 K for 48 h, and the effective magnetic refrigeration capacity reached 191 J/kg.

Hardness distribution and effect of irradiation in FSW-ODS ferritic steels

International Nuclear Information System (INIS)

Noh, Sanghoon; Kasada, Ryuta; Kimura, Akihiko; Nagasaka, Takuya; Sokolov, M.A.; Yamamoto, T.

2014-01-01

Oxide dispersion strengthened ferritic steels (ODS-FS) have been considered as one of the most promising structural materials for advanced nuclear systems such as fusion reactors and next generation fission reactors, because of its excellent elevated temperature strength, corrosion and radiation resistance. Especially, irradiation resistance is a critical issue for the high performance of ODS-FS. In this study, effects of the irradiation on hardness properties of friction stri processed (FSP) ODS-FS were investigated. FSP technique was employed on ODS-FS. A plate specimen was cut out from the cross section and irradiated to 1.2 dpa at 573K in the High Flux Isotope Reactor (HFIR). To investigate the effect of neutron irradiation on processed area, the hardness distributions were evaluated on the cross section. Hardness of FSP ODS-FS was various with each microstructure after irradiation to 1.2 dpa at 573K. The increase of Vickers hardness was significant in the stirred zone and heat affected zone. Base material exhibited the lowest hardening about 38HV. Since nano-oxide particles in stirred zone showed identical mean diameter and number density, it is considered that hardening differences between stirred zone and base material is due to differences in initial dislocation density. (author)

Effects of alpha radiation on hardness and toughness of the borosilicate glass applied to radioactive wastes immobilization

International Nuclear Information System (INIS)

Prado, Miguel Oscar; Bernasconi, Norma B. Messi de; Bevilacqua, Arturo Miguel; Arribere, Maria Angelica; Heredia, Arturo D.; Sanfilippo, Miguel

1999-01-01

Borosilicate german glass SG7 samples, obtained by frit sintering, were irradiated with different fluences of thermal neutrons in the nucleus of a nuclear reactor. The nuclear reaction 10 B(n,α) 7 Li, where the 10 B isotope is one of the natural glass components, was used to generate alpha particles throughout the glass volume. The maximum alpha disintegration per unit volume achieved was equivalent to that accumulated in a borosilicate glass with nuclear wastes after 3.8 million years. Through Vickers indentations values for microhardness, stress for 50% fracture probability (Weibull statistics) and estimation of the toughness were obtained as a function of alpha radiation dose. Two counterbalanced effects were found: that due to the disorder created by the alpha particles in the glass and that due to the annealing during irradiation (temperature below 240 deg C). Considering the alpha radiation effect, glasses tend decrease Vickers hardness, and to increase thr 50% fracture probability stress with the dose increase. (author)

Efek perendaman rebusan Daun Sirih Merah (Piper crocatum terhadap kekerasan permukaan resin komposit

Directory of Open Access Journals (Sweden)

Devi Puspita Handayani

2016-08-01

Full Text Available The effect of immersion of decoction water of Red Betel Leaf (Piper crocatum on the surface hardness of composite resin. The purpose of this study was to determine the effect of immersion of decoction water of red betel leaf on the surface hardness of composite resin compared to alcoholic mouth rinse. It was a pure experimental study with post-test only with control group design. The total samples were 27 samples divided into 2 treatment groups and 1 control group, each of which consisted of 9 samples. The treatment groups were immersed in the decoction water of red betel leaf and alcoholic mouth rinse. The control group was immersed in aquadest. After the immersion, the samples were measured using Vickers Micro hardness Tester. Analysis with one way anova and post hoc Bonferroni showed a significant difference (p<0.05 on the surface hardness of composite resin after being immersed in decoction water of red betel leaf(79,81±3,76 kg/mm2 and alcoholic mouth rinse (67,11±2,51 kg/mm2. Based on this research, it can be concluded that there was an effect of immersion of decoction water of red betel leaf if compared with alcoholic mouth rinse. The value of surface hardness of composite resin immersed in alcoholic mouth rinse was lower than the decoction water of red betel leaf. ABSTRAK Penelitian ini bertujuan untuk mengetahui efek perendaman dalam rebusan daun sirih merah terhadap kekerasan permukaan resin komposit bila dibandingkan dengan obat kumur beralkohol. Penelitian ini merupakan penelitian eksperimental murni dengan post-test only with control group design. Jumlah sampel sebanyak 27 yang dibagi dalam 2 kelompok perlakuan dan 1 kelompok kontrol dengan masing-masing kelompok sebanyak 9 sampel. Kelompok perlakuan direndam dengan air rebusan daun sirih merah dan obat kumur beralkohol. Kelompok kontrol direndam dengan akuades steril. Setelah itu dilakukan pengukuran menggunakan Vickers Microhardness Tester. Hasil uji One Way Anova dan Post Hoc

Determination of the penetration hardness and analysis of stainless steel alloys by means of Laser Induced Breakdown Spectroscopy (LIBS

Directory of Open Access Journals (Sweden)

mohamad Vahid Dastjerdi

2017-11-01

Full Text Available A significant feature of alloys is the surfaces hardness that is always accompanied by challenges when it’s measured by common mechanical techniques. In this investigation, we used Laser Induced Breakdown Spectroscopy (LIBS as a replacement method for common mechanical techniques to measure the surfaces hardness of different alloys. After recording the spectrum of alloy samples in order to identify the surface hardness of analyzed sample, K-Nearest Neighbors method (KNN was used and obtained results showed that the LIBS-KNN method can separate and identify the surfaces hardness of samples with precision of 93.3%. In addition, in order to identify the percentage of constituent elements of alloys and their hardness, calibration approach was investigated that showed there is an appropriate linear relation between recorded emission lines from the LIB spectra of sample alloys and the percentage of their constituent elements and also their Vickers hardness numbers. Therefore, According to exclusive advantages of LIBS technique i.e. high speed analysis, non-destructive analysis and being portable, some of available difficulties in conventional mechanical techniques can be removed.

Effect of shot peening using ultra-fine particles on fatigue properties of 5056 aluminum alloy under rotating bending

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, Shoichi, E-mail: kikuchi@mech.kobe-u.ac.jp [Department of Mechanical Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe-shi, Hyogo 657-8501 (Japan); Nakamura, Yuki [Department of Mechanical Engineering, National Institute of Technology, Toyota College, 2-1 Eisei-cho, Toyota-shi, Aichi 471-8525 (Japan); Nambu, Koichiro [Department of Mechanical Engineering, National Institute of Technology, Suzuka College, Shiroko-cho, Suzuka-shi, Mie 510-0294 (Japan); Ando, Masafumi [Innovation Team, IKK SHOT Co. Ltd., 412-4, Nunowari, Minami-Shibata-machi, Tokai-shi, Aichi 476-0001 (Japan)

2016-01-15

Shot peening using particles 10 μm in diameter (ultra-fine particle peening: Ultra-FPP) was introduced to improve the fatigue properties of 5056 aluminum alloy. The surface microstructures of the Ultra-FPP treated specimens were characterized using a micro-Vickers hardness tester, scanning electron microscopy (SEM), X-ray diffraction (XRD), non-contact scanning white light interferometry, and electron backscatter diffraction (EBSD). The Ultra-FPP treated specimen had higher hardness than the conventional FPP treated specimen with a short nozzle distance due to the high velocity of the ultra-fine particles. Furthermore, the surface hardness of the Ultra-FPP treated specimen tended to increase as the peening time decreased. Fatigue tests were performed in air at room temperature using a cantilever-type rotating bending fatigue testing machine. It was found that the fatigue life of the Ultra-FPP treated specimen tended to increase with decreasing peening time. Mainly, the Ultra-FPP improved the fatigue properties of 5056 aluminum alloy in the very high cycle regime of more than 10{sup 7} cycles compared with the un-peened specimens. This is because the release of the compressive residual stress is small during fatigue tests at low stress amplitudes.

Research on microstructure properties of the TiC/Ni-Fe-Al coating prepared by laser cladding technology

Science.gov (United States)

Jiao, Junke; Xu, Zifa; Zan, Shaoping; Zhang, Wenwu; Sheng, Liyuan

2017-10-01

In this paper, the laser cladding method was used to preparation the TiC reinforced Ni-Fe-Al coating on the Ni base superalloy. The Ti/Ni-Fe-Al powder was preset on the Ni base superalloy and the powder layer thickness is 0.5mm. A fiber laser was used the melting Ti/Ni-Fe-Al powder in an inert gas environment. The shape of the cladding layer was tested using laser scanning confocal microscope (LSCM) under different cladding parameters such as the laser power, the melting velocity and the defocused amount. The microstructure, the micro-hardness was tested by LSCM, SEM, Vickers hardness tester. The test result showed that the TiC particles was distributed uniformly in the cladding layer and hardness of the cladding layer was improved from 180HV to 320HV compared with the Ni-Fe-Al cladding layer without TiC powder reinforced, and a metallurgical bonding was produced between the cladding layer and the base metal. The TiC powder could make the Ni-Fe-Al cladding layer grain refining, and the more TiC powder added in the Ni-Fe-Al powder, the smaller grain size was in the cladding layer.

Vickers Terminator. Volume 3C(VT) - Technical appraisal. Consultants' 1983 report

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

A report is given by a team of consultants on the estimated cost of converting wave energy to electrical energy by a 2 GW array of Vickers Terminator wave energy devices and delivering the electricity to a sub-station on the west coast of Skye. Comparisons with the estimates made by the team developing the concept are presented and are largely in agreement, except for the capital cost per device and the power chain efficiency. A detailed engineering assessment is given.

The influence of topical application of grapeseed extract gel on enamel surface hardness after demineralization

Science.gov (United States)

Saragih, D. A.; Herda, E.; Triaminingsih, S.

2017-08-01

The aim of this study was to analyze the influence of topical application of 6.5% and 12.5% grapeseed extract gels for duration of application 16 and 32 minutes on the enamel surface hardness following tooth demineralization by an energy drink. The samples were 21 bovine teeth that underwent demineralization by immersion in the energy drink for 5 minutes in an incubator at 37°C. The demineralized specimens were randomly divided into a control group and 2 treatment groups. The control group was immersed in artificial saliva for 6 hours at 37°C, whereas the treatment groups were treated with topical 6.5% and 12.5% grapeseed extract gels for durations of 16 and 32 minutes and then immersed in artificial saliva for 6 hours at 37°C. The hardness was measured with a Knoop hardness tester. Statistical analysis by repeated ANOVA and one-way ANOVA revealed a significant increase in the enamel hardness value (p0.05).

Thermal-aging evaluation of on site aged cast duplex stainless steel

International Nuclear Information System (INIS)

Yamada, Takuyo; Fujii, Katsuhiko; Aoki, Masanori; Arioka, Koji

2013-01-01

In this study, thermal-aging evaluation has been performed using service aged elbow pipe in PWR plant, aged at 320degC for 196,500h. As a result, micro Vickers hardness of ferrite in service material (SCS14A), HV(0.025) was 616∼630. Since micro Vickers hardness of un-aged ferrite phase is about HV(0.025)=300 in commercial SCS14A, the increasing of ferrite hardness during aging was 300. Cr-rich and Fe-rich regions were observed in the ferrite phase using Atom-probe analysis. In addition, Ni, Si and Mo clustering were also observed in the ferrite phase. So the ferrite phase was hardened caused by these micro-structural changes. Micro Vickers hardness of austenite phase, HV(0.025) was 155∼180. Since micro Vickers hardness of un-aged austenite phase is about HV(0.025)=180∼200, and no micro-structural change was observed in the austenite phase, so on change was observed in the austenite phase during aging. To compare the micro Vickers hardness of ferrite in service and accelerated materials using activation energy, Q=100 kJ/mol, the ferrite hardness of in service material was very low rather than predictive line. This seems the activation energy was too conservative. (author)

White balance tester with color sensor for industrial applications

Science.gov (United States)

Chen, Jiasheng; Zhu, XiaoSong

1996-12-01

The white balance tester is an instrument that adjusts the white balance for color TVs, monitors, and PC displays. We have designed a new white balance tester for use directly at the production line. It picks up the R (Red), G (Green), and B (Blue) signals for the screen using color sensors, compares the signals with the data previously stored in the internal memory, displays their differences with LED bars in the compare mode or displays x y Y, u v Y, JND (just noticeable difference) as well as correlated color temperature in the numerical mode. A built-in TV signal generator sets the luminance of the adjusting screen to the brightness of the reference white screen automatically. A 16-bit single chip microcomputer processes the measured values and controls the output levels of the TV signal generator.

Microindentation hardness evaluation of iridium alloy clad vent set cups

International Nuclear Information System (INIS)

Ulrich, G.B.; DeRoos, L.F.; Stinnette, S.E.

1993-01-01

An iridium alloy, DOP-26, is used as cladding for 238 PuO 2 fuel in radioisotope heat sources for space power systems. Presently, DOP-26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y-12 Plant for potential use in the National Aeronautics and Space Administration's Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams-force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP-26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP-26 alloy grain boundaries have higher hardnesses than the grain interiors

Microindentation hardness evaluation of iridium alloy clad vent set cups

International Nuclear Information System (INIS)

Ulrich, G.B.; DeRoos, L.F.; Stinnette, S.E.

1992-01-01

An iridium alloy, DOP-26, is used as cladding for 238 PuO 2 fuel in radioisotope heat sources for space power systems. Presently, DOP-26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y-12 Plant for potential use in the National Aeronautics and Space Administration's Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams-force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP-26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP-26 alloy grain boundaries have higher hardnesses than the grain interiors

Microprocessor-controlled tester for evaluation of the Self-Energized Credential System (SECS)

International Nuclear Information System (INIS)

Corlis, N.E.

1980-03-01

The Self-Energized Credential System (SECS) was developed for use in the Plutonium Protection System (PPS) installed at Hanford, Washington. Evaluation and development of the SECS system was enhanced by the use of a microprocessor-controlled portal tester. This tester used infrared (ir) beam sensors to provide information on the direction of travel of the credential wearer and to detect inoperative credentials. A printed record of the portal number, actual code read, time, and direction of the credential passage provided information essential to an assessment of the operability of the SECS

Enhancement of as-sputtered silver-tantalum oxide thin film coating on biomaterial stainless steel by surface thermal treatment

Science.gov (United States)

Alias, Rodianah; Mahmoodian, Reza; Shukor, Mohd Hamdi Abd; Yew, Been Seok; Muhamad, Martini

2018-04-01

Stainless steel 316L (SS316L) is extensively used as surgical/clinical tools due to its low carbon content and excellent mechanical characteristic. The fabrication of metal ceramic based on this metallic biomaterial favor its biofunctionality properties. However, instability phase of amorphous thin film lead to degradation, corrosion and oxidation. Thus, thin film coating requires elevated adhesion strength and higher surface hardness to meet clinical tools criteria. In this study, the SS316L was deposited with micron thickness of Ag-TaO thin film by using magnetron sputtering. The microstructure, elemental analysis and phase identification of Ag-TaO thin film were characterized by using FESEM, EDX and XRD, respectively; whereas the micro scratch test and micro hardness test were performed by using Micro Scratch Testing System and Vickers Micro Hardness Tester, respectively. It was found that the coating thin film's adhesion and hardness strength were improved from 672 to 2749 mN and 142 to 158 Hv respectively. It was found that the as-deposited surface were treated at 500 °C of temperatures with 2 °C/min ramping rate enhance 4.1 times of the adhesion strength value. Furthermore, FESEM characterization revealed coarsening structure of the thin film coating which can provide high durability service.

Building instructions: a motorcar battery tester

Energy Technology Data Exchange (ETDEWEB)

Kunz, K

1975-02-01

The circuit diagram of a motor car battery tester is given, intended for dashboard mounting. The condition of the battery is indicated by means of a light-emitting diode, which may be off (below 11 V), red (11 to 12.5 V), green (12.5 to 14.8 V) or flashing red (voltage exceeding 14.8 V). The circuit uses two transistors and a single integrated circuit (four-way comparator). Details of the layout, assembly, and testing procedures are included.

A study on the improvement on the surface characteristics of STS403 stainless steel by chromizing and boronizing

International Nuclear Information System (INIS)

Kim, Kwang Seok; Lee, Sang Yul; Lee, Eui Yeoul

1999-01-01

STS403 stainless steel substrate was treated by duplex treatment of chromizing and boronizing. Metallographic cross sections of the treated specimens were consisted of duplex layer, layer, Cr diffusion layer, and matrix. Microstructures of duplex layer and others layers formed on STS403 were examined by OM, SEM, EDS, XRD and surface properties of duplex layer were evaluated by micro-Vickers hardness tester, wear tester and corrosion tester. From the XRD analysis of the duplex layer, various phases such as FeB, Fe 2 B, CrB were identified. The results from EDS analysis showed that intermedium layer contained much more Cr than any other layers. The activation energy for the diffusion of boron in the chromium diffusion layer in the duplex treated STS403 steel was calculated to be approximately 220kJ/mole, which was higher than the diffusional activation energy of boron in the STS403 steel, 160kJ/mole. Microhardness of duplex layer was measured to be approximately Hv1800∼2000 (50 gf). On high temperature wear testing at 600 .deg. C, duplex treated specimen exhibited an excellent wear resistance, showing that the wear volume of the duplex treated specimen was approximately five times smaller than that of untreated specimen. From the result of anodic polarization curves in 1M, H 2 SO 4 solution, duplex treated specimen showed an excellent corrosion resistance than the specimen treated by boronizing only

Effectiveness of anchovy substrate application on decreasing acid solubility of Sprague Dawley rats’ tooth enamel (in vivo)

Science.gov (United States)

Triputra, F.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Anchovies (Stolephorus insularis), a natural resource of Indonesia, contain fluoride in the form of CaF2 and can function as a fluoridation material to prevent dental caries. The aim of this study is to study the effectiveness of anchovy substrate, through food or topical application, in decreasing the acid solubility of tooth enamel. This research used 14 Sprague Dawley rats as subjects divided into the following 5 groups: baseline, experimental feeding, experimental smearing, and their negative controls. After 15 days of anchovy substrate application, lower incisors were extracted and the acid solubility of enamel was analyzed qualitatively and quantitatively using a stereo microscope and a Micro-Vickers Hardness Tester. Analysis of enamel surface destruction and enamel surface microscopic hardness shifting after a 60 sec application of H2PO4 (50% concentration) resulted in a decrease in acid solubility of enamel treated with anchovy substrate. This result can be seen with both the chewing and smearing method. S. insularis can be used as an alternative material for fluoridation.

The effect of surface nanocrystallization on plasma nitriding behaviour of AISI 4140 steel

Energy Technology Data Exchange (ETDEWEB)

Li Yang [Department of Materials Science and Engineering, Dalian Maritime University, Institute of Metals and Technology, 1 Linghai Street, Dalian 116026 (China); Wang Liang, E-mail: wlimt@yahoo.com [Department of Materials Science and Engineering, Dalian Maritime University, Institute of Metals and Technology, 1 Linghai Street, Dalian 116026 (China); Zhang Dandan; Shen Lie [Department of Materials Science and Engineering, Dalian Maritime University, Institute of Metals and Technology, 1 Linghai Street, Dalian 116026 (China)

2010-11-15

A plastic deformation surface layer with nanocrystalline grains was produced on AISI 4140 steel by means of surface mechanical attrition treatment (SMAT). Plasma nitriding of SMAT and un-SMAT AISI 4140 steel was carried out by a low-frequency pulse excited plasma unit. A series of nitriding experiments has been conducted at temperatures ranging from 380 to 500 deg. C for 8 h in an NH{sub 3} gas. The samples were characterized using X-ray diffraction, scanning electron microscopy, optical microscopy and Vickers microhardness tester. The results showed that a much thicker compound layer with higher hardness was obtained for the SMAT samples when compared with un-SMAT samples after nitriding at the low temperature. In particular, plasma nitriding SMAT AISI 4140 steel at 380 deg. C for 8 h can produced a compound layer of 2.5 {mu}m thickness with very high hardness on the surface, which is similar to un-SMAT samples were plasma nitrided at approximately 430 deg. C within the same time.

Effect of four over-the-counter tooth-whitening products on enamel microhardness.

Science.gov (United States)

Majeed, A; Grobler, S R; Moola, M H; Oberholzer, T G

2011-10-01

This in vitro study evaluated the effect of four over-the-counter tooth-whitening products on enamel microhardness. Fifty enamel blocks were prepared from extracted human molar teeth. The enamel surfaces were polished up to 1200 grit fineness and the specimens randomly divided into five groups. Enamel blocks were exposed to: Rapid White (n=10); Absolute White (n=10); Speed White (n=10) and White Glo (n=10) whitening products, according to the manufacturers' instructions. As control, ten enamel blocks were kept in artificial saliva at 37 degrees C without any treatment. Microhardness values were obtained before exposure (baseline) and after 1, 7 and 14-day treatment periods using a digital hardness tester with a Vickers diamond indenter. Data were analysed using Wilcoxon Signed Rank Sum Test, one-way ANOVA and Tukey-Kramer Multiple Comparison Test (penamel microhardness. Speed White increased the microhardness of enamel, while White Glo and artificial saliva had no effect on hardness. Over-the-counter tooth-whitening products might decrease enamel microhardness depending on the type of product.

Influence of yttrium on microstructure and properties of Ni–Al alloy coatings prepared by laser cladding

Directory of Open Access Journals (Sweden)

Cun-shan Wang

2014-03-01

Full Text Available Ni–Al alloy coatings with different Y additions are prepared on 45# medium steel by laser cladding. The influence of Y contents on the microstructure and properties of Ni–Al alloy coatings is investigated using X-ray diffraction, scanning electron microscopy, electron probe microanalyzer, Vickers hardness tester, friction wear testing machine, and thermal analyzer. The results show that the cladding layers are mainly composed of NiAl dendrites, and the dendrites are gradually refined with the increase in Y additions. The purification effect of Y can effectively prevent Al2O3 oxide from forming. However, when the atomic percent of Y addition exceeds 1.5%, the extra Y addition will react with O to form Y2O3 oxide, even to form Al5Y3O12 oxide, depending on the amount of Y added. The Y addition in a range of 1.5–3.5 at.% reduces the hardness and anti-attrition of cladding layer, but improves obviously its wear and oxidation resistances.

Trial manufacture of rotary friction tester and frictional force measurement of metals

CERN Document Server

Abe, T; Kanari, M; Tanzawa, S

2002-01-01

In the plasma confinement type fusion reactor, in-vessel structures such as a blanket module slide at the joints each other when plasma disruption occurs, and then frictional heat is generated there. Therefore, for the selection of material and the use as the design data, it is important to understand the frictional characteristics of metals and ceramic films in the vacuum. In the present study, we have manufactured a prototype of rotary friction tester and examined the performances of the tester. The frictional characteristics of metals in the room air was measured using the friction tester, and the results obtained are as follows. A drifting friction force for a constant time and a friction force during the idling were 98 mN and 225 mN, respectively. These values were sufficiently small as compared to pressing load (9.8 - 57.8 N) used in the friction test. In a friction force measurement of stainless steel, dynamic friction force obeyed Amontons' law which indicated that dynamic friction force is not depend...

Vickers microhardness comparison of 4 composite resins with different types of filler.

Directory of Open Access Journals (Sweden)

René García-Contreras

2015-10-01

Full Text Available Composite resins are the material of choice to restore minimal invasive cavities; conversely, it is important to explore the mechanical properties of commercially available dental materials. Objective: To compare the Vickers microhardness (VHN of four available commercial composite resins using standardized samples and methods. Methodology: Composite cylinders were manufactured in a Teflon mould. We used the follow composite resins (n=4/gp: Microhybrid resins [Feeling Lux (Viarden and Amelogen Plus (Ultradent], Hybrid resin [Te-Econom Plus (Ivoclar] and Nanohybrid resin [Filtek Z350 (3M ESPE]. All samples were incubated in distilled water at 37ºC for five days. The test was carried out with microhardness indenter at 10 N, and a dwelling time of 10 s for 9 indentations across the specimens resulting in a total of 36 indentations for each group. Data were subjected to Kolmogorov-Smirnov normality test and ANOVA (post-hoc Tukey test. Results: The VHN mean values ranged from harder to softer as follows: Filtek Z350 (71.96±6.44 (p Amelogen Plus (59.90±4.40 (p Feeling lux (53.52±5.72> Te-Econom Plus (53.26±5.19. Conclusion: According to our results, the microhardness of the evaluated conventional composite resins can withstand the masticatory forces; however nanohybrid composite resins showed better Vickers microhardness and therefore are a more clinically suitable option for minimal invasion treatments.

Requirement analysis of testers qualified for aircraft compatibility test x-ray diagnostic and interventional radiology in Indonesia

International Nuclear Information System (INIS)

Diah Astuti Indarwati; Haendra Subekti

2013-01-01

Analysis of the need of Qualified Tester by calculating the number of test team to perform conformance test of diagnostic and interventional X-ray equipment has been done. This analysis was conducted in order to map the needs of Qualified Testers in Indonesia. As the conformance test certificate will be used in the licensing process, the availability of Tester will greatly affect the continuity and smoothness of the licensing process. The result shows the number of required test team is currently as much as 49 teams, while the availability of the test team is 7 test team. Thus there is still a large gap between the need and availability of the test team to perform conformance test. For the central and eastern of Indonesia on the scope of CT Scan, Mammography, Fluoroscopy and can only be met by tester in Java. (author)

Microstructure evolution and hardness change in ordered Ni3V intermetallic alloy by energetic ion irradiation

International Nuclear Information System (INIS)

Hashimoto, A.; Kaneno, Y.; Semboshi, S.; Yoshizaki, H.; Saitoh, Y.; Okamoto, Y.; Iwase, A.

2014-01-01

Ni 3 V bulk intermetallic compounds with ordered D0 22 structure were irradiated with 16 MeV Au ions at room temperature. The irradiation induced phase transformation was examined by means of the transmission electron microscope (TEM), the extended X-ray absorption fine structure measurement (EXAFS) and the X-ray diffraction (XRD). We also measured the Vickers hardness for unirradiated and irradiated specimens. The TEM observation shows that by the Au irradiation, the lamellar microstructures and the super lattice spot in diffraction pattern for the unirradiated specimen disappeared. This TEM result as well as the result of XRD and EXAFS measurements means that the intrinsic D0 22 structure of Ni 3 V changes into the A1 (fcc) structure which is the lattice structure just below the melting point in the thermal equilibrium phase diagram. The lattice structure change from D0 22 to A1 (fcc) accompanies a remarkable decrease in Vickers microhardness. The change in crystal structure was discussed in terms of the thermal spike and the sequential atomic displacements induced by the energetic heavy ion irradiation

Rapidly Adaptable Instrumentation Tester (RAIT)

International Nuclear Information System (INIS)

Vargo, Timothy D.

1999-01-01

Emerging technologies in the field of ''Test ampersand Measurement'' have recently enabled the development of the Rapidly Adaptable Instrumentation Tester (RAIT). Based on software developed with LabVIEW, the RAIT design enables quick reconfiguration to test and calibrate a wide variety of telemetry systems. The consequences of inadequate testing could be devastating if a telemetry system were to fail during an expensive flight mission. Supporting both open-bench testing as well as automated test sequences, the RAIT has significantly lowered total time required to test and calibrate a system. This has resulted in an overall lower per unit testing cost than has been achievable in the past

Hardness of model dental composites - the effect of filler volume fraction and silanation.

Science.gov (United States)

McCabe, J F; Wassell, R W

1999-05-01

The relationship between structure and mechanical properties for dental composites has often proved difficult to determine due to the use of commercially available materials having a number of differences in composition i.e. different type of resin, different type of filler, etc. This makes a scientific study of any one variable such as filler content difficult if not impossible. In the current study it was the aim to test the hypothesis that hardness measurements of dental composites could be used to monitor the status of the resin-filler interface and to determine the efficacy of any particle silanation process. Ten model composites formulated from a single batch of resin and containing a common type of glass filler were formulated to contain varying amounts of filler. Some materials contained silanated filler, others contained unsilanated filler. Specimens were prepared and stored in water and hardness (Vickers') was determined at 24 h using loads of 50, 100, 200 and 300 g. Composites containing silanated fillers were significantly harder than materials containing unsilanated fillers. For unsilanated products hardness was independent of applied load and in this respect they behaved like homogeneous materials. For composites containing silanated fillers there was a marked increase in measured hardness as applied load was increased. This suggests that the hardness-load profile could be used to monitor the status of the resin-filler interface. Copyright 1999 Kluwer Academic Publishers

Usefulness of new wetness tester for diagnosis of dry mouth in disabled patients.

Science.gov (United States)

Kakinoki, Yasuaki; Nishihara, Tatsuji; Arita, Masahiro; Shibuya, Koji; Ishikawa, Masao

2004-12-01

The condition of dry mouth is an influential factor in the incidence of caries, periodontal disease, fungal infections, masticatory dysfunctions and denture function. Bedridden elderly and disabled persons often suffer from oral dryness and the aim of this study was to evaluate the usefulness of measuring the amount of moisture in the oral mucosa for clinical diagnosis of dry mouth in this group. The subjects were 20 elderly bedridden individuals, age range 65-89 years old, living in a nursing home and six healthy laboratory researchers, aged 20-46 years old, used as controls. Tongue dorsum moisture measurements were performed using a newly developed wetness tester (L-SALIVO), in which the wet portion was measured after 10 s. Further, clinical diagnosis of dry mouth was carried out using a clinical classification scale of the tongue mucosa (grade range, 0-3). It was possible to measure tongue dorsum moisture in all subjects with the wetness tester. The average moisture value was 0.1+/-0.2 mm in elderly subjects with a dry mouth grade of 2 (n = 8) or 3 (n = 12), while the average moisture value in the control subjects was 3.67+/-1.75 mm with a dry mouth grade of 0 (n = 4) or 1 (n = 2). Tester values and cliniical classification showed a positive co-relationship (r = 0.31, p < 0.05). Our results show that this new tester could be useful for evaluating oral dryness and diagnosing dry mouth.

Software testing an ISTQB-BCS certified tester foundation guide

CERN Document Server

Hambling, Brian; Samaroo, Angelina; Thompson, Geoff; Williams, Peter; Hambling, Brian

2015-01-01

This practical guide provides insight into software testing, explaining the basics of the testing process and how to perform effective tests. It provides an overview of different techniques and how to apply them. It is the best-selling official textbook of the ISTQB-BCS Certified Tester Foundation Level.

Patient perceptions and expectations of an anticoagulation service: a quantitative comparison study of clinic-based testers and patient self-testers.

Science.gov (United States)

Money, Arthur G; Barnett, Julie; Kuljis, Jasna; Duffin, Debbie

2015-12-01

Government initiatives see the provision of technology-assisted self-care as one of the key areas in which there is capacity for improving quality of care whilst reducing costs. However, levels of patient engagement in self-testing and management (STM) remain low. Little emphasis has been placed on understanding the patients' perspectives of the reasons for this limited engagement. Typically, patient engagement in STM is achieved via the provision of patient education programmes, which aim to enable patients to make the changes necessary to become competent self-carers. However, placing the onus to change on the individual patient is unrealistic. If levels of patient engagement are to be improved, patient needs and expectations of clinical services must be better understood and service provision must be adapted accordingly. Explore patient perceptions and expectations of clinical service provision and their views of having and making choices about care. Participants [N = 191, 103 patient self-tester managers (PSTMs) and 87 clinic-based testers (CBTs)] completed the SERVQUAL and ChQ instruments to capture perspectives on service quality and choice, respectively. A comparative statistical analysis explored the similarities and differences between PSTMs' and CBTs' responses. Clinic-based testers' perceptions of service quality were significantly more positive than PSTMs', as were their expectations of the 'tangible' aspects of service delivery. PSTMs' expectations of service quality were significantly higher than their perceptions. PSTMs attributed significantly more value to making choices compared with CBTs. To close the gap between PSTMs expectations and perceptions of service quality and better cater for their choice preferences, service providers may benefit from taking into account the following practice considerations: maintain frequent, timely, personalised and direct interactions with PSTMs; prioritise investment in resources to facilitate patient

Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester (IQT)

KAUST Repository

Naser, Nimal; Yang, Seung Yeon; Kalghatgi, Gautam; Chung, Suk-Ho

2016-01-01

an ignition quality tester. A baseline data of ignition delay times were determined using an ignition quality tester at a charge pressure of 21.3 bar between 770 and 850 K and an equivalence ratio of 0.7 for various primary reference fuels (PRFs, mixtures

Effect of Er,Cr:YSGG laser irradiation on bovine enamel surface during in-office tooth bleaching ex vivo.

Science.gov (United States)

Dionysopoulos, Dimitrios; Strakas, Dimitrios; Koliniotou-Koumpia, Eugenia; Koumpia, Effimia

2017-07-01

The aim of this in vitro study was to evaluate the effect of using Er,Cr:YSGG laser during in-office tooth bleaching on bovine enamel surface to evaluate the safety of this therapy on tooth tissues. Thirty-six enamel specimens were prepared from bovine incisors and divided into three groups: Group 1 specimens (control) received no bleaching treatment; Group 2 received a conventional in-office bleaching treatment (40 % H 2 O 2 ); Group 3 received laser-assisted bleaching procedure (40 % H 2 O 2 ) utilizing an Er,Cr:YSGG laser. The specimens were stored for 10 days after the bleaching treatment in artificial saliva. Vickers hardness was determined using a microhardness tester, and measurements for surface roughness were done using a VSI microscope. Three specimens for each experimental group were examined under SEM and mineral composition of the specimens was evaluated using EDS. Data were statistically analyzed using one-way ANOVA, Tukey's post hoc, Wilcoxon signed rank and Kruskal-Wallis tests (a = 0.05). The Vickers hardness of the enamel was reduced after in-office bleaching procedures (p  0.05), and no changes in mineral composition of the enamel were detected after in-office bleaching procedures (p > 0.05). The laser-assisted bleaching treatment with Er,Cr:YSGG laser did not influence the enamel surface compared to the conventional bleaching technique. The safety of the use of Er,Cr:YSGG laser during in-office tooth bleaching regarding the surface properties of the enamel was confirmed under in vitro conditions.

Mechanical properties and three-body wear of dental restoratives and their comparative flowable materials.

Science.gov (United States)

Schultz, Sabine; Rosentritt, Martin; Behr, Michael; Handel, Gerhard

2010-01-01

To compare wear performance and resistance to crack propagation (K1C) of commercial restorative materials and their flowable variations. A potential correlation between three-body wear and fracture toughness, modulus of elasticity, fracture work, Vickers hardness, and filler content was investigated. Seven restoratives (five composites, one ormocer, and one compomer) and their corresponding flowable materials were used to determine and compare the three-body wear with a bolus of millet-seed shells and rice food (Willytec). The wear characteristics were measured by profilometry after 50,000, 100,000, 150,000, and 200,000 loading cycles. The fracture toughness value, K1C (MPam1/2), for each single-edged notched specimen was measured in a three-point bending test (universal testing machine 1446, Zwick). Fracture work and modulus of elasticity were calculated from the load curves. Vickers hardness was measured (HV hardness tester, Zwick) according to DIN 50133. The veneering composite Sinfony (3M ESPE) was used as a reference material. Heavily filled composites experienced less wear than their flowable variations. The nanofiller composites revealed better wear results than hybrid composites, compomers, and ormocers. After 200,000 load cycles, the lowest wear rates were detected for Grandio (14 microm; Voco), and the highest mean values were found for Dyract AP (104 microm; Dentsply DeTrey). The values for fracture toughness (K1C) ranged from 0.82 to 3.64 MPam1/2. Highest K1C data was exhibited by the nanocomposite Nanopaq (Schutz Dental). All tested restorative materials exhibited higher fracture toughness than their low-viscosity variations. The wear resistance of the newer generation composites with incorporated nanofiller or microfiller particles increased to a high extent. Flowables show less resistance against wear and crack propagation because of their lower filler content. The reduced mechanical properties limit their use as a restorative to small noncontact

The difference nanocomposite hardness level using LED photoactivation based on curing period variations

Directory of Open Access Journals (Sweden)

Hasiana Tatian

2011-03-01

Full Text Available Polimerizatian is the critical stage to determine the quality of composites resin, this involves isolated monomer carbon double bonds being converted to an extended network of single bonds. Physical and mechanical properties of composites are influenced by the level of conversion attained during polymerization. An adequate light intensity and light curing time are important to obtain the degree of polymerization. The objective of this study is to evaluate the difference of the hardness nanocomposites which activated by LED LCU based on the variation of curing times. This study is a true experimental research. The samples were made from nanocomposites material with cylinder form of 4 mm in depth, 6 mm in diameter. This samples divided into 3 groups of curing times. Group, I was cured for 20's curing time as a control due to manufactory recommended; Group II was cured for 30's, and Group III was cured for 40's and the hardness (Rebound hardness tester was determined using Rebound scale (RS and converted by Mohs scale (MS. There was a very significant level of hardness rate from each group using ANOVA test. The result of the study concludes that there were the differences on the nanocomposites hardness level cured under different curing times 20, 30 and 40 sec. The longer of curing times, the higher level of hardness.

Correlation between hardness and stress in Al-(Nb, Mo, Ta) thin films

Energy Technology Data Exchange (ETDEWEB)

Car, T., E-mail: car@irb.h [Rudjer Boskovic Institute, Division of Materials Science, Bijenicka cesta 54, 10000 Zagreb, P.O.B. 1016 (Croatia); Radic, N. [Rudjer Boskovic Institute, Division of Materials Science, Bijenicka cesta 54, 10000 Zagreb, P.O.B. 1016 (Croatia); Panjan, P.; Cekada, M. [Jozef Stefan Institute, Ljubljana (Slovenia); Tonejc, A. [Department of Physics, Bijenicka cesta 32, 10000 Zagreb, P.O.B. 331 (Croatia)

2009-06-30

The thin films of Al{sub x}Nb{sub 1-x} (95 {>=} x {>=} 20), Al{sub x}Mo{sub x} (90 {>=} x {>=} 20) and Al{sub x}Ta{sub 1-x} (95 {>=} x {>=} 20) were prepared by magnetron codeposition at room temperature. The average film thickness was from 325 to 400 nm, depending on the film composition. The structure of the as-deposited films was examined by the X-ray diffraction. The stress of the films was determined from the substrate deformation by the profilometer, and the microhardness (load 2 mN) was examined by the micro- and nano-hardness device. For the purpose of the examination of the hardness, the samples were deposited onto the sapphire wafers, while the examination of the film stress, was performed by using thin glass substrates. For all the Al-(Nb, Mo, Ta) alloy compositions, the microhardness is predominantly under the influence of the harder element, and monotonically decreases with the increase of the aluminum content. However, the microhardness of the amorphous AlTa films was higher than the bulk value of a harder element (Ta) in the alloy. A simple empirical linear relationship between the Vickers hardness, the bulk value hardness of the transition metal (harder element) and the elastic energy fraction of the identation deformation, was established. The elastic energy fraction in the microhardness is also linearly correlated with the stress in films.

Enhanced electrical conductivity and hardness of silver-nickel composites by silver-coated multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Lee, Dongmok; Sim, Jeonghyun; Baik, Seunghyun; Kim, Wonyoung; Moon, Chuldong; Cho, Wookdong

2015-01-01

We investigated electrical conductivity and Vickers hardness of Ag- and Ni-based composites prepared by powder metallurgy involving spark plasma sintering. The starting composition was Ag:Ni = 61:39 vol%, which provided an electrical conductivity of 3.30 × 10"5 S cm"−"1 and a hardness of 1.27 GPa. The addition of bare multi-walled carbon nanotubes (MWNTs, 1.45 vol%) increased hardness (1.31 GPa) but decreased electrical conductivity (2.99 × 10"5 S cm"−"1) and carrier mobility (11 cm"2 V"−"1 s"−"1) due to the formation of Ni_3C in the interface between the MWNTs and Ni during spark plasma sintering. The formation of Ni_3C was prevented by coating the surface of the nanotubes with Ag (nAgMWNTs), concomitantly increasing electrical conductivity (3.43 × 10"5 S cm"−"1) and hardness (1.37 GPa) of the sintered specimen (Ag:Ni:nAgMWNTs = 59.55:39:1.45 vol%). The electrical contact switching time (133 357) was also increased by 30%, demonstrating excellent feasibility as electrical contact materials for electric power industries. (paper)

Mechanical properties of materials used for temporary fixed dentures – in vitro study

Directory of Open Access Journals (Sweden)

Celej-Piszcz Elzbieta

2017-06-01

Full Text Available Objectives. The objective of the research was to define the mechanical properties of currently marketed temporary filling materials. Methods. Eight temporary filling materials: Boston, Dentalon, Protemp II, Revotek LC, Structure 2, Structure 3, UniFast LC, UniFast Trad were used to make 5 samples each of measurements 2 × 2 × 25 mm, in order to define the flexural strength, and 10 rings each of measurements 2 × 5 mm, in order to carry out the Vickers micro-hardness test. After preparation, the samples were stored in distilled water of temperature of 370°C, for 7 days. Subsequently, flexural strength and Vickers hardness testing was undertaken. Results. Composite temporary materials showed considerably better mechanical properties, both in flexural strength and in Vickers micro-hardness testing. Conclusions. the best mechanical properties, both in terms of flexural strength, as well as Vickers micro-hardness test can be observe among composite materials.

Reliability of knee joint range of motion and circumference measurements after total knee arthroplasty: does tester experience matter?

DEFF Research Database (Denmark)

Jakobsen, Thomas Linding; Christensen, Malene; Christensen, Stine Sommer

2010-01-01

: The design was an intra-tester, inter-tester and intra-day reliability study. Nineteen outpatients (10 females) having received a TKA were examined by an inexperienced and an experienced physiotherapist. Following a standardized protocol, active and passive knee joint ROM and circumference measurements were...

16 CFR Figure 4 to Subpart A of... - Flooring Radiant Panel Tester Schematic Low Flux End, Elevation

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flooring Radiant Panel Tester Schematic Low Flux End, Elevation 4 Figure 4 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY... Standard Pt. 1209, Subpt. A, Fig. 4 Figure 4 to Subpart A of Part 1209—Flooring Radiant Panel Tester...

Antibacterial characteristics of thermal plasma spray system.

Science.gov (United States)

Goudarzi, M; Saviz, Sh; Ghoranneviss, M; Salar Elahi, A

2018-03-15

The objective of this study is to investigate antibacterial characteristics of a thermal plasma spray system. For this purpose, copper powder was coated on a handmade atmospheric plasma spraying system made by the stainless steel 316 substrate, which is preheated at different temperatures before spraying. A number of deposition characteristics such as antibacterial characteristics, adhesion strength and hardness of coating, was investigated. All of the spray parameters are fixed except the substrate temperature. The chemical composition was analyzed by X-ray diffraction (XRD). A scanning electron microscopy (SEM) and back scattering electron microscopy (BSE) were used to show the coating microstructure, its thickness and also the powder micrograph. The energy dispersive X-ray spectroscopy (EDX) was used to analyze the coating particles. Hardness of the deposition was examined by Vickers tester (HV0.1). Its adhesion strength was declared by cross cut tester (TQC). In addition, the percentage of bactericidal coating was evidenced with Staphylococcus aurous and Escherichia coli bacteria. Study results show that as the substrates temperature increases, the number of splats in the shape of pancake increases, the greatness and percentage of the deposition porosity both decrease. The increment of the substrate temperature leads to more oxidation and makes thicker dendrites on the splat. The enhancement of the substrate temperature also enlarges thickness and efficiency of coating. The interesting results are that antibacterial properties of coatings against the Escherichia coli are more than Staphylococcus aurous bacteria. However the bactericidal percentage of the coatings against Staphylococcus aurous and Escherichia coli bacteria roughly does not change with increasing the substrate temperature. Furthermore, by increment of the substrate temperature, coatings with both high adhesion and hardness are obtained. Accordingly, the temperature of substrate can be an

Experimental investigation on hard turning of AISI 4340 steel using cemented coated carbide insert

Science.gov (United States)

Pradeep Kumar, J.; Kishore, K. P.; Ranjith Kumar, M.; Saran Karthick, K. R.; Vishnu Gowtham, S.

2018-02-01

Hard turning is a developing technology that offers many potential advantages compared to grinding, which remains the standard finishing process for critical hardened surfaces. In this work, an attempt has been made to experimentally investigate hard turning of AISI 4340 steel under wet and dry condition using cemented coated carbide insert. Hardness of the workpiece material is tested using Brinell and Rockwell hardness testers. CNC LATHE and cemented coated carbide inserts of designation CNMG 120408 are used for conducting experimental trials. Significant cutting parameters like cutting speed, feed rate and depth of cut are considered as controllable input parameters and surface roughness (Ra), tool wear are considered as output response parameters. Design of experiments is carried out with the help of Taguchi’s L9 orthogonal array. Results of response parameters like surface roughness and tool wear under wet and dry condition are analysed. It is found that surface roughness and tool wear are higher under dry machining condition when compared to wet machining condition. Feed rate significantly influences the surface roughness followed by cutting speed. Depth of cut significantly influences the tool wear followed by cutting speed.

Effects of solute elements on hardening of thermally-aged RPV model alloys

International Nuclear Information System (INIS)

Dohi, Kenji; Nishida, Kenji; Nomoto, Akiyoshi; Soneda, Naoki; Liu, Li; Sekimura, Naoto; Li Zhengcao

2012-01-01

The investigation of effects of solute elements on the copper-enriched cluster, which is a cause of radiation embrittlement of reactor pressure vessel steels, is needed in order to understand the mechanism of the hardening and the cluster formation. The dependence of the hardness change and the formation of thermally-aged Fe-Cu model alloys doped Ni, Si and Mn on aging time are investigated using Vickers harness tester and three dimensional atom probe. Ni addition suppresses hardening, and Si addition accelerates hardening slightly at the initial stage of the aging. Mn addition accelerates hardening much more but does not almost affect the peak hardness. Ni and Si addition increase the number density and the size of the cluster, while Mn addition remarkably increases the number density and the size of the cluster at the initial stage of the aging. In addition, there is no clear correlation between the square root of the volume fraction of the clusters and the hardness change for all of the alloys. The reasons are considered to be the decrease in the solute hardening caused by the cluster formation and the difference in the shear modulus of the cluster due to the difference in the chemical composition of the cluster. (author)

Local microstructures, Hardness and mechanical properties of a stainless steel pipe-welded joint

International Nuclear Information System (INIS)

Zhao Yongxiang; Gao Qing; Cai Lixun

2000-01-01

An experimental investigation is carefully performed into the local microstructures, hardness values and monotonic mechanical properties of the three zones (the base metal, heat affecting zone and weld metal) of 1Cr18Ni9Ti stainless steel pipe-welded joint. The local microstructures are observed by a metallurgical test and a surface replica technology, the local hardness values are measures by a random Vickers hardness test, and the local mechanical properties are characterized by the Ramberg-Osgood and modified Ramberg-Osgood stress-stain relations. The investigation reveals that there are significant differences of the three zones in the local microstructures, hardness values and monotonic mechanical properties, especially of the three zones in the local microstructure, hardness values and monotonic mechanical properties, especially of the weld metal. The weld metal exhibits the largest heterogeneity of local microstructures and monotonic mechanical properties, and the largest scatter of local hardness values. It is necessary to consider these difference and introduce the reliability method to model the scatter in the pipe analysis. In addition, it is verified that a columnar grain structure, which is made up of matrix-rich δ ferrite bands, can characterize the weld metal and the distance between the neighboring rich δ ferrite bands is an appropriate measurement of the columnar grain structure. This measurement is in accordance with the transition point between the microstructural short crack and physical small crack stages, which are generally used for characterizing the short fatigue crack behavior of materials. This indicates that the microstructure controls the fatigue damage character of the present material

submitter Test strategies for industrial testers for converter controls equipment

CERN Document Server

Oleniuk, P; Kasampalis, V; Nisbet, D; Todd, B; Uznański, S

2017-01-01

Power converters and their controls electronics are key elements for the operation of the CERN accelerator complex, having a direct impact on its availability. To prevent early-life failures and provide means to verify electronics, a set of industrial testers is used throughout the converters controls electronics' life cycle. The roles of the testers are to validate mass production during the manufacturing phase and to provide means to diagnose and repair failed modules that are brought back from operation. In the converter controls electronics section of the power converters group in the technology department of CERN (TE/EPC/CCE), two main test platforms have been adopted: a PXI platform for mixed analogue-digital functional tests and a JTAG Boundary-Scan platform for digital interconnection and functional tests. Depending on the functionality of the device under test, the appropriate test platforms are chosen. This paper is a follow-up to results presented at the TWEPP 2015 conference, adding the boundary s...

A study on hardness behavior of geopolymer paste in different condition

Science.gov (United States)

Zainal, Farah Farhana; Hussin, Kamarudin; Rahmat, Azmi; Abdullah, Mohd Mustafa Al Bakri; Shamsudin, Shaiful Rizam

2016-07-01

This study has been conducted to understand the hardness behavior of geopolymer paste in different conditions; with and without being immersed in water. Geopolymer paste has been used nowadays as an alternative way to reduce global warming pollution by carbon dioxide (CO2) released to the air caused from the production of Ordinary Portland Cement (OPC). Geopolymer has many advantages such as high compressive strength, lower water absorption and lower porosity. Geopolymer paste in this study was made from a mixture of fly ash and alkaline activators. The alkaline activators that have been used were sodium hydroxide (NaOH) solution and sodium silicate (Na2SiO3) solution. Then the mixture was allowed to harden for 24hrs at ambient temperature and then placed in the oven for 24hrs with 60°C for the curing process. The hardness testing was conducted after a few months when the samples already achieved the optimum design. The samples were divided to two conditions; without immersion which was placed at ambient temperature (S1) and immersed in water for one week (S2). The samples then are divided into two at the center and testing was conducted into 4 parts which are part 1, part 2, part 3 and part 4. Various methods of non-destructively testing concrete and mortar have been in use for many years such as Vickers hardness test, Rockwell hardness test, Brinell hardness test and many more. The Rockwell hardness test method as defined in ASTM E-18 is the most commonly used hardness test method which is also used in this study. From the results, S1 has higher hardness value than S2 for all parts with the maximum value of S1 is 118.6 and the minimum value is 71.8. The maximum value of S2 is 114.4 and the minimum value is 0. The central part of the geopolymer paste also showed greater hardness values than the edge area of the samples.

Surface Modification of Metals using Plasma Torch

International Nuclear Information System (INIS)

Hassan, A.

2009-01-01

Low temperature plasma nitriding of 304L stainless steel is performed using a home made low power direct-current plasma torch. Plasma nitriding is carried out in temperature range of 300-550 degree C for 1 to 4 hours, in various N 2 H 2 gas mixture ratios at about 5 Torr pressure and torch power 300 Watts. The effect of treatment time, temperature and working gas composition on the microstructure and mechanical properties of plasma nitrided surface layers is investigated. The microstructure, phase composition and micro hardness profile of the nitrided surface layers are characterized by optical microscopy, scanning electron microscope (SEM), X-ray diffraction (XRD) and Vickers micro hardness tester. The results show that plasma treatment for 14 h over a temperature range of 300 - 550 degree C yields nitride case depth of 20 - 50 μm and the hardness of the nitrided layer is in the range of 700-1250 HV. Plasma nitriding of stainless steel samples at about 475 degree C in 70 % of nitrogen admixed with hydrogen at 5 torr shows the maximum increase of hardness 1220 HV which is about four times that of untreated layers. The XRD pattern confirmed the formation of an expanded austenite .N phase, due to the nitrogen incorporation into original lattice and forms supersaturated face center cubic phase. In addition preliminary results for aluminum nitriding is also shown

Tester Detects Steady-Short Or Intermittent-Open Circuits

Science.gov (United States)

Anderson, Bobby L.

1990-01-01

Momentary open circuits or steady short circuits trigger buzzer. Simple, portable, lightweight testing circuit sounds long-duration alarm when it detects steady short circuit or momentary open circuit in coaxial cable or other two-conductor transmission line. Tester sensitive to discontinuities lasting 10 microseconds or longer. Used extensively for detecting intermittent open shorts in accelerometer and extensometer cables. Also used as ordinary buzzer-type continuity checker to detect steady short or open circuits.

Pengaruh Lama Perendaman dan Jenis Minuman Beralkohol Bir dan Tuak terhadap Kekerasan Email Gigi Manusia (In Vitro

Directory of Open Access Journals (Sweden)

Malida Magista

2014-06-01

Full Text Available Erosi gigi merupakan hilangnya lapisan email gigi karena asam. Jenis asam, pH rendah, serta kandungan kalsium, fosfat, dan fluoride pada bir dan tuak diduga merupakan faktor kimiawi penyebab erosi gigi. Tujuan penelitian ini untuk mengetahui pengaruh lama perendaman dan jenis minuman beralkohol bir dan tuak terhadap kekerasan email gigi manusia (in vitro. Penelitian ini menggunakan 14 sampel gigi premolar pertama atas. Setiap gigi dibagi menjadi 2 bagian, bukal dan palatal. kemudian dibagi menjadi 7 kelompok perlakuan, yaitu kelompok (A1 perendaman dalam bir (ringan; (A2 kelompok perendaman dalam bir sedang; kelompok (A3 perendaman dalam bir berat, kelompok (B1: perendaman dalam tuak ringan, (B2: perendaman dalam tuak sedang, (B3: perendaman dalam tuak berat dan kelompok kontrol (C. Uji kekerasan email gigi dilakukan menggunakan Micro Vickers Hardness Tester. Pengujian kekerasan awal email gigi dilakukan sebelum perendaman gigi. Perendaman gigi premolar pertama atas pada bir dan tuak dilakukan selama 10 detik, 50 detik, dan 250 detik perhari dengan penyimpanan subjek penelitian pada saliva buatan. Uji kekerasan akhir email gigi dilakukan setelah perlakuan selama 30 hari. Nilai perubahan kekerasan email gigi merupakan selisih nilai kekerasan akhir dan nilai kekerasan awal email gigi. Sebagai tambahan data, pada bir dan tuak juga diukur kandungan pH, kalsium, dan fosfor. Data dianalisis menggunakan uji ANAVA dua jalur dilanjutkan dengan uji LSD. Hasil analisis ANAVA dua jalur menujukkan bahwa jenis minuman dan lama perendaman berpengaruh bermakna terhadap kekerasan email gigi (p<0,05. Hasil uji LSD menunjukkan adanya perbedaan rerata yang signifikan (p<0,05 antar kelompok uji bir dan tuak. Kesimpulan dari penelitian ini adalah terdapat pengaruh jenis minuman beralkohol bir dan tuak dan lama perendaman terhadap kekerasan email gigi manusia (in vitro. The Effect Of Contact Time And Alcohol Beverages Beer And Tuak On Human Dental Enamel Hardness (In

Fracture toughness of glasses and hydroxyapatite: a comparative study of 7 methods by using Vickers indenter

OpenAIRE

HERVAS , Isabel; MONTAGNE , Alex; Van Gorp , Adrien; BENTOUMI , M.; THUAULT , A.; IOST , Alain

2016-01-01

International audience; Numerous methods have been proposed to estimate the indentation fracture toughness Kic for brittle materials. These methods generally uses formulæ established from empirical correlations between critical applied force, or average crack length, and classical fracture mechanics tests. This study compares several models of fracture toughness calculation obtained by using Vickers indenters. Two optical glasses (Crown and Flint), one vitroceramic (Zerodur) and one ceramic (...

Effects of the bleaching procedures on enamel micro-hardness: Plasma Arc and diode laser comparison.

Science.gov (United States)

Nematianaraki, Saeid; Fekrazad, Reza; Naghibi, Nasim; Kalhori, Katayoun Am; Junior, Aldo Brugnera

2015-10-02

One of the major side effects of vital bleaching is the reduction of enamel micro-hardness. The purpose of this study was to evaluate the influence of two different bleaching systems, Plasma Arc and GaAlAs laser, on the enamel micro-hardness. 15 freshly extracted human third molars were sectioned to prepare 30 enamel blocks (5×5 mm). These samples were then randomly divided into 2 groups of 15 each (n=15): a plasma arc bleaching group (: 350-700 nm) + 35% Hydrogen Peroxide whitening gel and a laser bleaching group (GaAlAs laser, λ: 810 nm, P: 10 W, CW, Special Tip) + 35% Hydrogen Peroxide whitening gel. Samples were subjected to the Vickers micro-hardness test (VHN) at a load of 50 g for 15s before and after treatment. Data were statistically analyzed by a Mann-Whitney test (p≤0.05). In the GaAlAs laser group, the enamel micro-hardness was 618.2 before and was reduced to 544.6 after bleaching procedures. In the plasma arc group, the enamel micro-hardness was 644.8 before and 498.9 after bleaching. Although both techniques significantly reduced VHN, plasma arc bleaching resulted in a 22.62% reduction in VHN for enamel micro-hardness, whereas an 11.89% reduction in VHN was observed for laser bleaching; this difference is statistically significant (plaser than with the plasma arc. Therefore GaAlAs laser bleaching has fewer harmful effects than plasma arc in respect to enamel micro-hardness reduction.

Comparison of local and imported osteosynthetic mandibular bone plates in terms of micro hardness in modified simulated body fluid at periodic intervals

International Nuclear Information System (INIS)

Anwar, R.; Kaleem, M.; Baig, AM.; Jamal, M.

2015-01-01

To determine the micro hardness of novel Pakistani manufactured osteosynthetic titanium bone mini plates (MPP) and imported osteosynthetic titanium bone mini plates (MPG) in body like conditions. Study Design: Descriptive study. Place and Duration of Study: This study was carried out at School of Chemical and Material Engineering, NUST from March to May 2013. Material and Methods: Microvicker hardness tester was used for assessment of micro hardness of two types of plates. The hardness was checked before conditioning and after conditioning at (six different places) on interval of 1, 7,14,21,28 and 40 days in modified simulated body fluid with ph 7.4 and temperature 37 degree C. Results: Result showed that hardness of MPG was higher than MPP and after conditioning in simulated body fluid at all time periods, hardness of both types of plates was increased. Conclusion: It can be concluded from this study that micro hardness of imported plates is more than local plates so recommendations should be sent to manufacturers of local industry of Pakistan to improve the hardness of local plates so that they can meet international standards. (author)

Effect of Co on Si and Fe-containing intermetallic compounds (IMCs) in Al–20Si–5Fe alloys

International Nuclear Information System (INIS)

Fatih Kilicaslan, M.; Yilmaz, Fikret; Hong, Soon-Jik; Uzun, Orhan

2012-01-01

The effects of cobalt addition on microstructure and mechanical properties of Al–20Si–5Fe–XCo (X=0, 1, 3, and 5) alloys were reported in this study. The alloys were produced by both conventional sand casting and melt-spinning at 20 m/s disk velocity. Microstructures of the samples were investigated using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Vickers micro-hardness tester was used for hardness measurements. Results showed that Co addition can alter morphology of Fe-bearing intermetallic compounds (IMCs) from long rod/needle-like structures to short rod-like ones, and lead to a more homogenous distribution in the microstructure. Addition of 5 wt% Co leads to a decrease in average size of the primary silicon phases in as-cast Al–Si alloys. In melt-spun alloys, with the addition of Co, the microstructure became finer and more homogenously distributed, while thickness of the featureless zone has seen great increase. The optimum Fe to Co ratio was found to be 1 for suppressing the undesirable effect of Fe-bearing acicular/needle-like intermetallic compounds.

Effect of Co on Si and Fe-containing intermetallic compounds (IMCs) in Al-20Si-5Fe alloys

Energy Technology Data Exchange (ETDEWEB)

Fatih Kilicaslan, M. [Department of Physics, Faculty of Art and Science, Kastamonu University, Kastamonu (Turkey); Yilmaz, Fikret [Department of Physics, Faculty of Art and Science, Gaziosmanpasa University, Tokat (Turkey); Hong, Soon-Jik, E-mail: hongsj@kongju.ac.kr [Division of Advanced Materials Engineering, Institute for Rare Metals, Kongju National University, Cheonan 331717 (Korea, Republic of); Uzun, Orhan, E-mail: orhan.uzun@gop.edu.tr [Department of Physics, Faculty of Art and Science, Gaziosmanpasa University, Tokat (Turkey)

2012-10-30

The effects of cobalt addition on microstructure and mechanical properties of Al-20Si-5Fe-XCo (X=0, 1, 3, and 5) alloys were reported in this study. The alloys were produced by both conventional sand casting and melt-spinning at 20 m/s disk velocity. Microstructures of the samples were investigated using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Vickers micro-hardness tester was used for hardness measurements. Results showed that Co addition can alter morphology of Fe-bearing intermetallic compounds (IMCs) from long rod/needle-like structures to short rod-like ones, and lead to a more homogenous distribution in the microstructure. Addition of 5 wt% Co leads to a decrease in average size of the primary silicon phases in as-cast Al-Si alloys. In melt-spun alloys, with the addition of Co, the microstructure became finer and more homogenously distributed, while thickness of the featureless zone has seen great increase. The optimum Fe to Co ratio was found to be 1 for suppressing the undesirable effect of Fe-bearing acicular/needle-like intermetallic compounds.

Effects of delayed finishing/polishing on surface roughness, hardness and gloss of tooth-coloured restorative materials.

Science.gov (United States)

Yazici, A Ruya; Tuncer, Duygu; Antonson, Sibel; Onen, Alev; Kilinc, Evren

2010-01-01

The aim of this study was to investigate the effect of delayed finishing/polishing on the surface roughness, hardness and gloss of tooth-coloured restorative materials. Four different tooth-coloured restoratives: a flowable resin composite- Tetric Flow, a hybrid resin composite- Venus, a nanohybrid resin composite- Grandio, and a polyacid modified resin composite- Dyract Extra were used. 30 specimens were made for each material and randomly assigned into three groups. The first group was finished/polished immediately and the second group was finished/polished after 24 hours. The remaining 10 specimens served as control. The surface roughness of each sample was recorded using a laser profilometer. Gloss measurements were performed using a small-area glossmeter. Vickers microhardness measurements were performed from three locations on each specimen surface under 100g load and 10s dwell time. Data for surface roughness and hardness were analyzed by Kruskal Wallis test and data for gloss were subjected to one-way ANOVA and Tukey test (P gloss values were recorded under Mylar strip for all materials. While delayed finishing/polishing resulted in a significantly higher gloss compared to immediate finishing/polishing in Venus samples (P .05). The lowest hardness values were found under Mylar strip. Delayed finishing/polishing significantly increased the hardness of all materials. The effect of delayed finishing/polishing on surface roughness, gloss and hardness appears to be material dependent.

Enhanced Mechanical Properties of Laser Treated Al-Cu Alloys : A Microstructural Analysis

NARCIS (Netherlands)

Mol van Otterloo, J.L.de; Bagnoli, D.; de Hosson, J.T.M.

Both mechanical Vickers hardness and electron microscopic studies have been carried out on laser treated aluminium copper alloys with a copper concentration in the range 0-40 wt%. It is found that a Vickers hardness of 470 kgf/mm(2) can be attained, which is high compared to a value of 120 kgf/mm(2)

Blinded Comparison between an In-Air Reverberation Method and an Electronic Probe Tester in the Detection of Ultrasound Probe Faults.

Science.gov (United States)

Dudley, Nicholas J; Woolley, Darren J

2017-12-01

The aim of this study was to perform a blinded trial, comparing the results of a visual inspection of the in-air reverberation pattern with the results of an electronic probe tester in detecting ultrasound probe faults. Sixty-two probes were tested. A total of 28 faults were found, 3 only by in-air reverberation assessment and 2 only by the electronic probe tester. The electronic probe tester provided additional information regarding the location of the fault in 74% of the cases in which both methods detected a fault. It is possible to detect the majority of probe faults by visual inspection and in-air reverberation assessment. The latter provides an excellent first-line test, easily performed on a daily basis by equipment users. An electronic probe tester is required if detailed evaluation of faults is necessary. Copyright © 2017 World Federation for Ultrasound in Medicine and Biology. All rights reserved.

Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network.

Science.gov (United States)

De Filippis, Luigi Alberto Ciro; Serio, Livia Maria; Facchini, Francesco; Mummolo, Giovanni; Ludovico, Antonio Domenico

2016-11-10

A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW) process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable) and the mechanical properties (output responses) of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls). The simulation model was based on the adoption of the Artificial Neural Networks (ANNs) characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration.

Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network

Directory of Open Access Journals (Sweden)

Luigi Alberto Ciro De Filippis

2016-11-01

Full Text Available A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable and the mechanical properties (output responses of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls. The simulation model was based on the adoption of the Artificial Neural Networks (ANNs characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration.

High inter-tester reliability of the new mobility score in patients with hip fracture

DEFF Research Database (Denmark)

Kristensen, M.T.; Bandholm, T.; Foss, N.B.

2008-01-01

OBJECTIVE: To assess the inter-tester reliability of the New Mobility Score in patients with acute hip fracture. DESIGN: An inter-tester reliability study. SUBJECTS: Forty-eight consecutive patients with acute hip fracture at a median age of 84 (interquartile range, 76-89) years; 40 admitted from...... their own home and 8 from nursing homes to an acute orthopaedic hip fracture unit at a university hospital. METHODS: The New Mobility Score, which evaluates the prefracture functional level with a score from 0 (not able to walk at all) to 9 (fully independent), was assessed by 2 independent physiotherapists...... the prefracture functional level in patients with acute hip fracture Udgivelsesdato: 2008/7...

Effect of different hardness nanoparticles on friction properties of magnetorheological fluids

Science.gov (United States)

Zhao, Mingmei; Zhang, Jinqiu; Yao, Jun

2017-10-01

Magnetorheological fluids (MRFs) exhibit different wear performance when nanoparticles with different hardness are added. In this study, three solid particles with different hardness are considered to study the variation in MRF performance. The friction and wear properties of the MRF are measured by using a four-ball friction and wear tester, and the surface of the steel ball was observed using a three-dimensional white light interferometer. Also, the rheological properties of MRF are tested by using an Anton-Paar rheometer. The results show that the addition of graphite yields a stable friction process and does not degrade the rheological properties of MRF. Nano-diamond increases the shear yield strength and reduces the wall slip to a greater extent. However, the wear is more serious in this case. Copper particles are unstable, and their surface activity is too high to get adsorbed on the surface of iron powder aggravating the settlement rate. The above three MRFs with different kinds of nano-particles present a more regular grinding spot, and the nano-particles have a certain repair function to the surface.

Deposition and Characterization of the Titanium-Based Coating by a Multi-Chamber Detonation Sprayer

Directory of Open Access Journals (Sweden)

Arseenko M.Yu.

2015-01-01

Full Text Available This work introduces some of the aspects of the deposition of titanium-based coating (80-120 μm thick on aluminium samples using a multi-chamber detonation sprayer (MCDS. The characteristic feature of MCDS is that the powder is accelerated by using combustion products that are formed in MCDS chambers and are converged before entering the nozzle, where they interact with the two-phase gas-powder cloud. The microstructures and properties of the coating were characterized with the use of scanning electronic microscopes (SEM, optical microscope (OM, X-ray Diffraction (XRD techniques, and Vickers hardness tester with a 50 g test load. Wear tests were carried out using a computer controlled pin-on-disc type tribometer. It was established that MCDS has provided the conditions for formation of a dense titanium-based coating with a porosity of less than 1.0%, microhardness 810±250 HV0.05 and a specific wear rate of 2.077∙10-4 mm3(m∙N-1.

Plasma nitriding of CA-6NM steel: effect of H2 + N2 gas mixtures in nitride layer formation for low N2 contents at 500 ºC

Directory of Open Access Journals (Sweden)

Angela Nardelli Allenstein

2010-12-01

Full Text Available This work aims to characterize the phases, thickness, hardness and hardness profiles of the nitride layers formed on the CA-6NM martensitic stainless steel which was plasma nitrided in gas mixtures containing different nitrogen amounts. Nitriding was performed at 500 ºC temperature, and 532 Pa (4 Torr pressure, for gas mixtures of 5% N2 + 95% H2, 10% N2 + 90% H2, and 20% N2 + 80% H2, and 2 hours nitriding time. A 6 hours nitriding time condition for gas mixture of 5% N2 + 95% H2 was also studied. Nitrided samples results were compared with non-nitrided condition. Thickness and microstructure of the nitrided layers were characterized by optical microscopy (OM, using Villela and Nital etchants, and the phases were identified by X-ray diffraction. Hardness profiles and hardness measured on surface steel were determined using Vickers hardness and nanoindentation tester, respectively. It was verified that nitrided layer produced in CA-6NM martensitc stainless steel is constituted of compound layer, being that formation of the diffusion zone was not observed for the studied conditions. The higher the nitrogen amounts in gas mixture the higher is the thickness of the nitrided layer and the probability to form different nitride phases, in the case γ'-Fe4N, ε-Fe2-3N and CrN phases. Intrinsic hardness of the nitrided layers produced in the CA-6NM stainless steel is about 12-14 GPa (~1200-1400 HV.

Effect of Nb element content in U-Zr-Nb alloy on hardness, microstructure and phase formation

International Nuclear Information System (INIS)

Masrukan; M Husna Al Hasa; Jan Setiawan; Slamet Pribadi

2015-01-01

Experiments to determine the effect of Nb element in the U-Zr alloys on hardness, microstructure and phase formation has been done. The addition of Nb element would effect the hardness, microstructure and phase which formed. The U-Zr-Nb alloy was made with the variation of Nb 2%, 5% and 8% by melting in an electric arc melting furnace that equipped with water cooling and the argon atmosphere. The U-Zr-Nb alloy to be cut divided to some testing, such as hardness test, microstructure, and phase analysis. Hardness testing was done by Vickers hardness testing equipment, microstructure by an optical microscope, and diffraction pattern by XRD and phase analysis was done by GSAS. Hardness testing results showed that the addition of 2% to 5% Nb element in U-Zr alloys will increased in hardness, but the addition of Nb element over 5% the hardness was decreased. Observations the microstructure showed that the addition of 2% to 5% Nb element, grains were formed from fine into coarse. Phase analysis for diffraction pattern showed that the phase changed from αU and γU (Zr,Nb)at 2% Nb to be αU, γU (Zr,Nb) and δ1 (UZr_2) phase at 5% and 8% Nb. Phase changes was followed by changes in its compositions. The composition of αU at 2% Nb was 40% increased to 81% at 5% Nb and decreased to 3.9% at 8% Nb. The composition of γU decreased from 59,86% to 14,91% with increased Nb from 2% to 5% and further increased to 52,74% at 8% Nb. (author)

Test strategies for industrial testers for converter controls equipment

International Nuclear Information System (INIS)

Oleniuk, P.; Kasampalis, V.; Cosmo, M. Di; Nisbet, D.; Todd, B.; Uznański, S.

2017-01-01

Power converters and their controls electronics are key elements for the operation of the CERN accelerator complex, having a direct impact on its availability. To prevent early-life failures and provide means to verify electronics, a set of industrial testers is used throughout the converters controls electronics' life cycle. The roles of the testers are to validate mass production during the manufacturing phase and to provide means to diagnose and repair failed modules that are brought back from operation. In the converter controls electronics section of the power converters group in the technology department of CERN (TE/EPC/CCE), two main test platforms have been adopted: a PXI platform for mixed analogue-digital functional tests and a JTAG Boundary-Scan platform for digital interconnection and functional tests. Depending on the functionality of the device under test, the appropriate test platforms are chosen. This paper is a follow-up to results presented at the TWEPP 2015 conference, adding the boundary scan test platform and the first results from exploitation of the test system. This paper reports on the test software, hardware design and test strategy applied for a number of devices that has resulted in maximizing test coverage and minimizing test design effort.

Vickers Microhardness and Hyperfine Magnetic Field Variations of Heat Treated Amorphous Fe{sub 78}Si{sub 9}B{sub 13} Alloy Ribbons

Energy Technology Data Exchange (ETDEWEB)

Cabral-Prieto, A., E-mail: acpr@nuclear.inin.mx [Instituto Nacional de Investigaciones Nucleares, Department of Chemistry (Mexico); Garcia-Santibanez, F.; Lopez, A.; Lopez-Castanares, R.; Olea Cardoso, O. [Universidad Autonoma del Estado de Mexico, El Cerrillo Piedras Blancas, Facultad de Ciencias (Mexico)

2005-02-15

Amorphous Fe{sub 78}Si{sub 9}B{sub 13} alloy ribbons were heat treated between 296 and 763 K, using heating rates between 1 and 4.5 K/min. Whereas one ribbon partially crystallized at T{sub x} = 722 K, the other one partially crystallized at T{sub x} = 763 K. The partially crystallized ribbon at 722 K, heat treated using a triangular form for the heating and cooling rates, was substantially less fragile than the partially crystallized at 763 K where a tooth saw form for the heating and cooling rates was used. Vickers microhardness and hyperfine magnetic field values behaved almost concomitantly between 296 and 673 K. The Moessbauer spectral line widths of the heat-treated ribbons decreased continuously from 296 to 500 K, suggesting stress relief in this temperature range where the Vickers microhardness did not increase. At 523 K the line width decreased further but the microhardness increased substantially. After 523 K the line width behave in an oscillating form as well as the microhardness, indicating other structural changes in addition to the stress relief. Finally, positron lifetime data showed that both inner part and surface of Fe{sub 78}Si{sub 9}B{sub 13} alloy ribbons were affected distinctly. Variations on the surface may be the cause of some of the high Vickers microhardness values measured in the amorphous state.

Tester og testtilbakemeldinger som direkte bidragsytere til dypere læring blant studenter

Directory of Open Access Journals (Sweden)

Henrik Herrebrøden

2014-11-01

Full Text Available Denne artikkelen diskuterer forskning som tilsier at tester og testtilbakemeldinger kan bidra til dypere læring blant studenter. Testing har vist seg å forbedre langtidshukommelsen av innlært kunnskap sammenlignet med repetert lesing, noe som kalles for testeffekten. For at testeffekten skal optimaliseres, bør tester utformes med mål om å bidra til dyp prosessering av innlært kunnskap. Testtilbakemeldingers rolle i utdanning kan være å bidra til økt metakognitiv selvregulering blant studenter. For at selvregulering skal promoteres best mulig, bør testtilbakemeldinger inneholde utdypende informasjon. Samlet ser tester og testtilbakemeldinger ut til å være nyttige læringsverktøy og potensielle bidragsytere til dypere læring blant studenter.AbstractThis article discusses research supporting that tests and test feedback are learning tools that may promote deeper learning among students. Testing improves long-term retention of knowledge compared to repeated study, a phenomenon known as the testing effect. In order to promote the testing effect, tests should facilitate deep processing of knowledge among students. Test feedback has the potential to increase students’ metacognitive self-regulation. For this type of metacognition to be enhanced, feedback should contain elaborate information. Conclusively, tests and test feedback appear to be valuable learning tools and potential promoters of deeper learning.

Evaluation of material property of austenitic stainless steel using nano-indentation

Energy Technology Data Exchange (ETDEWEB)

Suyama, Takeshi [Institute of Nuclear Safety Systems Inc., Mihama, Fukui (Japan)

2001-09-01

In order to evaluate some material properties of very small area on small specimens which are sampled from components in service and to predict macroscopic material properties from the data of the small specimens, nano-indentation is considered to be quite effective. However, there are few reports formularize the dependence of load on hardness values evaluated from the results of indentation tests with loads from 10 mg to 100 g. In this study, systematic tests of indentation were conducted to specimens of austenitic stainless steel SUS304 using a Berkovich indenter and a Vickers indenter with loads varying from 10 mg to 100 g. From these results numerical formulae which relate the calculated hardness values to the loads were made. In addition, the relation between Vickers hardness and nano-indentation hardness was obtained. As a result, it became possible to predict Vickers hardness from nano-indentation with loads as low as about 100 mg. (author)

Effect of Bi-content on hardness and micro-creep behavior of Sn-3.5Ag rapidly solidified alloy

Energy Technology Data Exchange (ETDEWEB)

Kamal, M. [Metal Physics Laboratory, Faculty of Science, Mansoura University (Egypt); Gouda, El Said [Metal Physics Laboratory, Department of Solid State Physics, Physics Division, National Research Center, Dokki, Giza (Egypt); Marei, L.K. [Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt)

2009-12-15

In the present paper, the influence of 1, 3, 5 and 10 % Bi (weight %) as ternary additions on structure, melting and mechanical properties of rapidly solidified Sn-3.5Ag alloy has been investigated. The effect of Bi was discussed based on the experimental results. The experimental results showed that the alloys of Sn-3.5Ag, Sn-3.5Ag-1Bi and Sn-3.5Ag-3Bi are composed of two phases; Ag{sub 3}Sn IMC embedded in Sn matrix phase, which indicated that the solubility of Bi phase in Sn-matrix was extended to 3 % as a result of rapid solidification. Bi precipitation in Sn matrix was only observed in Sn-3.5Ag-5Bi and Sn-3.5Ag-10Bi alloys. Also, addition of Bi decreased continuously the melting point of the eutectic Sn-3.5Ag alloy to 202.6 C at 10 % Bi. Vickers hardness of Sn-3.5Ag rapidly solidified alloy increased with increasing Bi content up to 3 % due to supersaturated solid solution strengthening hardening mechanism of Bi phase in Sn matrix, while the alloys contain 5 and 10 % Bi exhibited lower values of Vickers hardness. The lower values can be attributed to the precipitation of Bi as a secondary phase which may form strained regions due to the embrittlement of Bi atom. In addition, the effect of Bi addition on the micro-creep behavior of Sn-3.5Ag alloy as well as the creep rate have been described and has been calculated at room temperature. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Hardness and microstructure of Al-10.0 wt% Zn-4.0 wt% Mg alloy

International Nuclear Information System (INIS)

Iqbal, M.; Shaikh, M.A.; Ahmad, W.; Ali, K.L.

1996-01-01

Al-Zn-Mg alloys are widely used in industries as these have excellent physical and mechanical properties. However some aspects of the effect of heat treatment on these alloys are not yet clear. In order to understand the precipitation phenomena in these alloys, microstructure of a locally prepared alloy Al-10.0 wt% Zn-4.0 wt% Mg heat treated under different conditions has been examined in scanning electron microscope/electron probe micro analyser. Precipitates MgZn/sub 2/, MgZn/sub 4/ and Mg/sub 2/Zn/sub 11/ have been observed and these are caused by heat treatment. Correlation between these precipitates and Vickers's hardness has also been studied. In the present paper results of this investigation have been presented and discussed. (author)

Hip strength assessment using handheld dynamometry is subject to intertester bias when testers are of different sex and strength

DEFF Research Database (Denmark)

Thorborg, K; Bandholm, T; Schick, M

2013-01-01

Handheld dynamometry (HHD) is a promising tool for obtaining reliable hip strength measurements in the clinical setting, but intertester reliability has been questioned, especially in situations where testers exhibit differences in upper-extremity muscle strength (male vs female). The purpose...... of this study was to examine the intertester reliability concerning strength assessments of hip abduction, adduction, external and internal rotation, flexion and extension using HHD, and to test whether systematic differences in test values exist between testers of different upper-extremity strength. Fifty...... healthy individuals (29 women), aged 25 ± 5 years were included. Two physiotherapist students (one female, one male) of different upper-extremity strength performed the measurements. The tester order and strength test order were randomized. Intraclass correlation coefficients were used to quantify...

Microstructure and Hardness of Cold Work Vanadis 6 Steel after Subzero Treatment at −140°C

Directory of Open Access Journals (Sweden)

Juraj Ďurica

2018-01-01

Full Text Available The microstructure, phase constitution, and hardness of Cr-V ledeburitic tool steel Vanadis 6 subjected to subzero treatment at −140°C and for different soaking times have been investigated. The light microscopy, scanning electron microscopy, and X-ray diffraction have been used for microstructural investigations. The hardness has been evaluated by the Vickers method. The obtained results assist to draw that subzero treatment reduces the retained austenite amount and increases the population density of carbides, compared to conventional heat treatment. The extent of decrease in the retained austenite amount makes around 85%, and the increase in population density of small globular carbides was approximately fivefold. High compressive stresses were identified in the retained austenite, and their values follow the increase in carbide count. This makes a serious support to the theory explaining the formation of “extra” carbides as a by-product of more complete martensitic transformation. As a result of the mentioned microstructural changes, the material hardness increased from 875 ± 16 HV 10 up to 954.6 ± 14 HV 10 for conventionally quenched and SZT steels, respectively.

Improving deposition tester to study adherent deposits in papermaking

OpenAIRE

Monte Lara, Concepción; Sánchez, Mónica; Blanco Suárez, Ángeles; Negro Álvarez, Carlos; Tijero Miquel, Julio

2012-01-01

Conventional methods used for the quantification of adherent material contained in a pulp suspension propose either filtration of the sample, which may lead to loss of sticky material in the filtrate, or dilution of the pulp, which may cause destabilization of the dissolved and colloidal material; thus, leading to unreliable results. In 1998, the Cellulose and Paper Group of University Complutense of Madrid developed a deposition tester which aimed to quantify the adherence of material (micro...

Nitride alloy layer formation of duplex stainless steel using nitriding process

Science.gov (United States)

Maleque, M. A.; Lailatul, P. H.; Fathaen, A. A.; Norinsan, K.; Haider, J.

2018-01-01

Duplex stainless steel (DSS) shows a good corrosion resistance as well as the mechanical properties. However, DSS performance decrease as it works under aggressive environment and at high temperature. At the mentioned environment, the DSS become susceptible to wear failure. Surface modification is the favourable technique to widen the application of duplex stainless steel and improve the wear resistance and its hardness properties. Therefore, the main aim of this work is to nitride alloy layer on the surface of duplex stainless steel by the nitriding process temperature of 400°C and 450°C at different time and ammonia composition using a horizontal tube furnace. The scanning electron microscopy and x-ray diffraction analyzer are used to analyse the morphology, composition and the nitrided alloy layer for treated DSS. The micro hardnesss Vickers tester was used to measure hardness on cross-sectional area of nitrided DSS. After nitriding, it was observed that the hardness performance increased until 1100 Hv0.5kgf compared to substrate material of 250 Hv0.5kgf. The thickness layer of nitride alloy also increased from 5μm until 100μm due to diffusion of nitrogen on the surface of DSS. The x-ray diffraction results showed that the nitride layer consists of iron nitride, expanded austenite and chromium nitride. It can be concluded that nitride alloy layer can be produced via nitriding process using tube furnace with significant improvement of microstructural and hardness properties.

Microhardness of the YbxY1-xInCu4 alloy system: the of electronic structure on hardness

International Nuclear Information System (INIS)

Ocko, M; Sarrao, J L; Stubicar, N; Aviani, I; Simek, Z; Stubicar, M

2003-01-01

We show that the Vickers microhardness, measured on flux grown single crystals of the Yb x Y 1-x InCu 4 alloy system, although sample dependent, exhibits clear concentration dependence; it increases with decreasing x. Such a dependence is not expected because the cubic lattice parameter increases with decreasing x and one expects then a decrease of hardness with decreasing x. Also, such a concentration dependence is in accordance with neither the Mott-Nabarro theory nor other known experimental results. We ascribe the observed dependence to the change of the electronic structure of the Yb x Y 1-x InCu 4 alloy system with x

NPS-SCAT (Solar Cell Array Tester), The Construction of NPS' First Prototype CubeSat

National Research Council Canada - National Science Library

Bein, Alexander L

2008-01-01

.... This Master's Thesis describes the NPS-SCAT (solar cell array tester) project, including the author's experience as program manager of the project, responsible for budget, schedule and technical deliverables...

MorphoTester: An Open Source Application for Morphological Topographic Analysis.

Directory of Open Access Journals (Sweden)

Julia M Winchester

Full Text Available The increased prevalence and affordability of 3D scanning technology is beginning to have significant effects on the research questions and approaches available for studies of morphology. As the current trend of larger and more precise 3D datasets is unlikely to slow in the future, there is a need for efficient and capable tools for high-throughput quantitative analysis of biological shape. The promise and the challenge of implementing relatively automated methods for characterizing surface shape can be seen in the example of dental topographic analysis. Dental topographic analysis comprises a suite of techniques for quantifying tooth surfaces and component features. Topographic techniques have provided insight on mammalian molar form-function relationships and these methods could be applied to address other topics and questions. At the same time implementing multiple complementary topographic methods can have high time and labor costs, and comparability of data formats and approaches is difficult to predict. To address these challenges I present MorphoTester, an open source application for visualizing and quantifying topography from 3D triangulated polygon meshes. This application is Python-based and is free to use. MorphoTester implements three commonly used dental topographic metrics-Dirichlet normal energy, relief index, and orientation patch count rotated (OPCR. Previous OPCR algorithms have used raster-based grid data, which is not directly interchangeable with vector-based triangulated polygon meshes. A 3D-OPCR algorithm is provided here for quantifying complexity from polygon meshes. The efficacy of this metric is tested in a sample of mandibular second molars belonging to four species of cercopithecoid primates. Results suggest that 3D-OPCR is at least as effective for quantifying complexity as previous approaches, and may be more effective due to finer resolution of surface data considered here. MorphoTester represents an advancement

Newly developed hardness testing system, "Cariotester": measurement principles and development of a program for measuring Knoop hardness of carious dentin.

Science.gov (United States)

Shimizu, Akihiko; Nakashima, Syozi; Nikaido, Toru; Sugawara, Toyotaro; Yamamoto, Takatsugu; Momoi, Yasuko

2013-01-01

We previously discovered that when a cone-shaped indenter coated with paint was pressed into an object, the paint disappeared in accordance with the depth of the indentation. Based on this fact, we developed the Cariotester, a portable system for measuring the Knoop hardness (KHN) of carious dentin. The Cariotester is composed of a handpiece with an indenter, a microscope, and a computer. In this system, the painted indenter is forced into the material with a 150-gf load, and the indentation depth (CT depth) is obtained from the paint disappearance. The CT depth by the Cariotester and the KHN by a microhardness tester were determined at 14 dentin regions. From the data, a program was created to convert the CT depth of the carious dentin into the KHN. As a result, if the CT depth is measured with this system, the KHN of carious dentin can be displayed in real time.

Effect of Y addition on the aging hardening behavior and precipitation evolution of extruded Mg-Al-Zn alloys

Energy Technology Data Exchange (ETDEWEB)

Ren, L.B. [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Quan, G.F., E-mail: quangf@home.swjtu.edu.cn [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhou, M.Y.; Guo, Y.Y.; Jiang, Z.Z.; Tang, Q. [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

2017-04-06

Abstract:: The 443 K aging hardening behavior and microstructure evolution of extruded Mg-Al-Zn-Y alloys was investigated in aspects of yttrium (Y) content (0.2–0.8 wt%), holding time (0.5–156 h) and the initial states (as-extruded, solution treated). The grain size, precipitation evolution, phases and chemical composition were characterized by the optical microscope, scanning electron microscope, X-ray diffraction, and energy dispersive spectrometer, respectively. The corresponding mechanical response, including the hardness, uniaxial tensile strength were measured with the Vickers hardness tester and universal testing machine, respectively. The results show that, firstly, there is reversal hardness anisotropy between extrusion direction and normal direction in as-extruded Mg-Al-Zn-Y sheets compared with T5 treated ones. Secondly, the short-term aging softening exist at the beginning of T5 treatment which results in a lower hardness even be close to that of solution treated ones, but not for T6 conditions. Thirdly, the suppression of discontinuous precipitation during the aging treatment become more remarkable with increasing Y addition which because of the reduction of diffusional coherency strain near grain boundary, increasing activation energy for the discontinuous precipitates (β-Mg{sub 17}Al{sub 12} phase, DPs) formation and the dilution region of Al near the Al{sub 2}Y. Serrated GBs can also provide more nucleation sites for DPs and lead to relatively more precipitates during T5 treatment. Moreover, the proportional precipitation strengthening in yield strength and hardness was verified in Mg-Al-Zn-Y alloy during the aging process.

Design, Construction, and Evaluation of Rubber Friction Tester

Directory of Open Access Journals (Sweden)

Mehdi Razzaghi Kashani

2012-12-01

Full Text Available Coeffcient of  friction  (COF  for  rubber parts  is one of  the key parameters in their interaction with solid rough surfaces (micrometer to millimeter scales,  such  as  tire-road  interactions. COF  of  rubber  depends  on  viscoelastic properties of rubber, roughness characteristics of the counter-part surface, and process variables such as contact nominal pressure and sliding speed. Due to the need for measuring COF  for  rubber,  a  new  friction  tester, with  continuous  variation  of nominal pressure and sliding speed, was designed and constructed in order to assess the effect of above mentioned parameters. Tire tread compounds, as the most common rubber part  in  the feld of  rubber  tribology, was used  for  this purpose. Viscoelastic properties of compounds were varied by changing composition of styrene-butadiene rubber (SBR and butadiene rubber (BR in the blend. Effect of surface roughness was evaluated by using silicon-carbide papers with different roughness parameters. By statistical analysis it was shown that the designed friction tester has high accuracy in measuring the coeffcient of friction of rubber and differentiating the effective parameters. Increasing the nominal pressure led to reduction of COF and increase in sliding speed forced it through a maximum. In conclusion, the loss factor of the compound and asymmetry in roughness distribution of the counter-surface are considered as the most effective parameters on COF of rubber.

Tactile Perception of Roughness and Hardness to Discriminate Materials by Friction-Induced Vibration

Directory of Open Access Journals (Sweden)

Shuyang Ding

2017-11-01

Full Text Available The human fingertip is an exquisitely powerful bio-tactile sensor in perceiving different materials based on various highly-sensitive mechanoreceptors distributed all over the skin. The tactile perception of surface roughness and material hardness can be estimated by skin vibrations generated during a fingertip stroking of a surface instead of being maintained in a static position. Moreover, reciprocating sliding with increasing velocities and pressures are two common behaviors in humans to discriminate different materials, but the question remains as to what the correlation of the sliding velocity and normal load on the tactile perceptions of surface roughness and hardness is for material discrimination. In order to investigate this correlation, a finger-inspired crossed-I beam structure tactile tester has been designed to mimic the anthropic tactile discrimination behaviors. A novel method of characterizing the fast Fourier transform integral (FFT slope of the vibration acceleration signal generated from fingertip rubbing on surfaces at increasing sliding velocity and normal load, respectively, are defined as kv and kw, and is proposed to discriminate the surface roughness and hardness of different materials. Over eight types of materials were tested, and they proved the capability and advantages of this high tactile-discriminating method. Our study may find applications in investigating humanoid robot perceptual abilities.

Development of a Portable Torque Wrench Tester

Science.gov (United States)

Wang, Y.; Zhang, Q.; Gou, C.; Su, D.

2018-03-01

A portable torque wrench tester (PTWT) with calibration range from 0.5 Nm to 60 Nm has been developed and evaluated for periodic or on-site calibration of setting type torque wrenches, indicating type torque wrenches and hand torque screwdrivers. The PTWT is easy to carry with weight about 10 kg, simple and efficient operation and energy saving with an automatic loading and calibrating system. The relative expanded uncertainty of torque realized by the PTWT was estimated to be 0.8%, with the coverage factor k=2. A comparison experiment has been done between the PTWT and a reference torque standard at our laboratory. The consistency between these two devices under the claimed uncertainties was verified.

Microstructural and hardness behavior of graphene-nanoplatelets/aluminum composites synthesized by mechanical alloying

International Nuclear Information System (INIS)

Pérez-Bustamante, R.; Bolaños-Morales, D.; Bonilla-Martínez, J.; Estrada-Guel, I.; Martínez-Sánchez, R.

2014-01-01

Highlights: • Pure aluminum was reinforced with graphene-platelets by using mechanical milling. • The composites were studied after sintering condition. • Milling time and graphene-platelet enhance the mechanical behavior of the composites. - Abstract: Graphene can be considered as an ideal reinforcement for the production of composites due to its outstanding mechanical properties. These characteristics offer an increased opportunity for their study in the production of metal matrix composites (MMCs). In this research, the studied composites were produced by mechanical alloying (MA). The employed milling times were of 1, 3 and 5 h. GNPs were added in 0.25, 0.50 and 1.0 wt% into an aluminum powder matrix. Milled powders were cold consolidated and subsequently sintered. Composites were microstructurally characterized with Raman spectroscopy and electron microscopy and X-ray diffraction. The hardness behavior in composites was evaluated with a Vickers micro-hardness test. A homogeneous dispersion of graphene during MA and the proper selection of sintering conditions were considered to produce optimized composites. The obtained results with electron microscopy indicate a homogeneous dispersion of GNPs into the aluminum matrix. Analyses showed GNPs edges where the structure of the graphene layers conserved after MA is observed

Physical properties and comparative strength of a bioactive luting cement.

Science.gov (United States)

Jefferies, Steven; Lööf, Jesper; Pameijer, Cornelis H; Boston, Daniel; Galbraith, Colin; Hermansson, Leif

2013-01-01

New dental cement formulations require testing to determine physical and mechanical laboratory properties. To test an experimental calcium aluminate/glass-ionomer cement, Ceramir C and B (CC and B), regarding compressive strength (CS), film thickness (FT), net setting time (ST) and Vickers hardness. An additional test to evaluate potential dimensional change/expansion properties of this cement was also conducted. CS was measured according to a slightly modified ISO 9917:2003 for the CC and B specimens. The samples were not clamped while being exposed to relative humidity of great than 90 percent at 37 degrees C for 10 minutes before being stored in phosphate-buffered saline at 37 degrees C. For the CS, four groups were tested: Group 1-CC and B; Group 2-RelyX Luting Cement; Group 3-Fuji Plus; and Group 4-RelyX Unicem. Samples from all groups were stored for 24 hours before testing. Only CCandB was tested for ST and FT according to ISO 9917:2003. The FT was tested 2 minutes after mixing. Vickers hardness was evaluated using the CSM Microhardness Indentation Tester using zinc phosphate cement as a comparison material. Expansion testing included evaluating potential cracks in feldspathic porcelain jacket crowns (PJCs). The mean and standard deviation after 24 hours were expressed in MPa: Group 1 equals 160 plus or equal to 27; Group 2 equals 96 plus or equal to 10; Group 3 equals 138 plus or equal to 15; Group 4 equals 157 plus or equal to 10. A single-factor ANOVA demonstrated statistically significant differences between the groups (P less than 0.001). Pair-wise statistical comparison demonstrated a statistically significant difference between Groups 1 and 2. No statistically significant differences were found between other groups. The FT was 16.8 plus or equal to 0.9 and the ST was 4.8 plus or equal to 0.1 min. Vickers hardness for Ceramir C and B was 68.3 plus or equal to 17.2 and was statistically significantly higher (P less than 0.05) than Fleck's Zinc Phosphate

Determining the fertility status of Setaria infecting Magnaporthe grisea isolates with standard testers and identification of tolerant cultivar of Setaria italica.

Science.gov (United States)

Karthikeyan, Veluswamy; Gnanamanickam, S S

2008-10-01

A total of 128 isolates of Setaria-infecting Magnaporthe grisea strains were obtained from different states of South India which includes sampling sites from Tamil Nadu, two from Karnataka, one from Andhra Pradesh and Kerala. Out of the selected 128 isolates 30 strains were tested with MAT1-1 and MAT1-2 fertile standard testers to determine their mating type. None of the 30 Setaria isolates produced perithecia with fertile testers. However, when monoconidial isolates were mated among themselves, isolates from the same field produced only barren perithecia and the tester isolates were able to mate readily with finger millet isolates. This is the first report of the mating-type studies on Setaria infecting Magnaporthe grisea with standard testers. This result indicates that the Setaria infecting population is infertile. In pathogenicity assay, it was found that 9 out of the 22 Setaria accessions were highly susceptible to Setaria strains of the blast fungus and seven cultivars/accessions were resistant to blast pathogen. Various virulence reactions were scored according to Standard Evaluation System.

Effect of light-curing method and indirect veneering materials on the Knoop hardness of a resin cement

Directory of Open Access Journals (Sweden)

Nelson Tetsu Iriyama

2009-06-01

Full Text Available This study evaluated the Knoop hardness of a dual-cured resin cement (Rely-X ARC activated solely by chemical reaction (control group or by chemical / physical mode, light-cured through a 1.5 mm thick ceramic (HeraCeram or composite (Artglass disc. Light curing was carried out using conventional halogen light (XL2500 for 40 s (QTH; light emitting diodes (Ultrablue Is for 40 s (LED; and Xenon plasma arc (Apollo 95E for 3 s (PAC. Bovine incisors had their buccal face flattened and hybridized. On this surface a rubber mold (5 mm in diameter and 1 mm in height was bulk filled with the resin cement. A polyester strip was seated for direct light curing or through the discs of veneering materials. After dry storage in the dark (24 h 37°C, the samples (n = 5 were sectioned for hardness (KHN measurements, taken in a microhardness tester (50 gF load 15 s. The data were statistically analyzed by ANOVA and Tukey's test (α = 0.05. The cement presented higher Knoop hardness values with Artglass for QTH and LED, compared to HeraCeram. The control group and the PAC/Artglass group showed lower hardness values compared to the groups light-cured with QTH and LED. PAC/HeraCeram resulted in the worst combination for cement hardness values.

A novel method to predict the highest hardness of plasma sprayed coating without micro-defects

Science.gov (United States)

Zhuo, Yukun; Ye, Fuxing; Wang, Feng

2018-04-01

The plasma sprayed coatings are stacked by splats, which are regarded generally as the elementary units of coating. Many researchers have focused on the morphology and formation mechanism of splat. However, a novel method to predict the highest hardness of plasma sprayed coating without micro-defects is proposed according to the nanohardness of splat in this paper. The effectiveness of this novel method was examined by experiments. Firstly, the microstructure of splats and coating, meanwhile the 3D topography of the splats were observed by SEM (SU1510) and video microscope (VHX-2000). Secondly, the nanohardness of splats was evaluated by nanoindentation (NHT) in order to be compared with microhardness of coating measured by microhardness tester (HV-1000A). The results show that the nanohardness of splats with diameter of 70 μm, 100 μm and 140 μm were in the scope of 11∼12 GPa while the microhardness of coating were in the range of 8∼9 GPa. Because the splats had not micro-defects such as pores and cracks in the nanohardness evaluated nano-zone, the nanohardness of the splats can be utilized to predict the highest hardness of coating without micro-defects. This method indicates the maximum of sprayed coating hardness and will reduce the test number to get high hardness coating for better wear resistance.

Hardness and wear properties of boron-implanted poly(ether-ether-ketone) and poly-ether-imide

International Nuclear Information System (INIS)

Lee Youngchul; Lee, E.H.; Mansur, L.K.

1992-01-01

The effects of boron beam irradiation on the hardness, friction, and wear of polymer surfaces were investigated. Typical high-performance thermoplastics, poly(ether-ether-ketone) (PEEK) and a poly-ether-imide (Ultem) were studied after 200 keV boron ion beam treatment at ambient temperature to doses of 2.3x10 14 , 6.8x10 14 , and 2.2x10 15 ions cm -2 . The hardnesses of pristine and boron-implanted materials were characterized by a conventional Knoop method and a load-depth sensing nanoindentation technique. Both measurements showed a significant increase in hardness with increasing dose. The increase in hardness was also found to depend on the penetration depth of the diamond indenter. Wear and friction properties were characterized by a reciprocating sliding friction tester with an SAE 52100 high-carbon, chrome steel ball at 0.5 and 1 N normal loads. Wear and frictional properties varied in a complex fashion with polymer type and dose, but not much with normal load. A substantial reduction in friction coefficient was observed for PEEK at the highest dose but no reduction was observed for Ultem. The wear damage was substantially reduced at the highest dose for both Ultem and PEEK. For the system studied, the highest dose, 2.2x10 15 ions cm -2 , appears to be optimum in improving wear resistance for both PEEK and Ultem. (orig.)

Effect of light-curing units, post-cured time and shade of resin cement on knoop hardness.

Science.gov (United States)

Reges, Rogério Vieira; Costa, Ana Rosa; Correr, Américo Bortolazzo; Piva, Evandro; Puppin-Rontani, Regina Maria; Sinhoreti, Mário Alexandre Coelho; Correr-Sobrinho, Lourenço

2009-01-01

The aim of this study was to evaluate the Knoop hardness after 15 min and 24 h of different shades of a dual-cured resin-based cement after indirect photoactivation (ceramic restoration) with 2 light-curing units (LCUs). The resin cement Variolink II (Ivoclar Vivadent) shade XL, A2, A3 and opaque were mixed with the catalyst paste and inserted into a black Teflon mold (5 mm diameter x 1 mm high). A transparent strip was placed over the mold and a ceramic disc (Duceram Plus, shade A3) was positioned over the resin cement. Light-activation was performed through the ceramic for 40 s using quartz-tungsten-halogen (QTH) (XL 2500; 3M ESPE) or light-emitting diode (LED) (Ultrablue Is, DMC) LCUs with power density of 615 and 610 mW/cm(2), respectively. The Koop hardness was measured using a microhardness tester HMV 2 (Shimadzu) after 15 min or 24 h. Four indentations were made in each specimen. Data were subjected to ANOVA and Tukey's test (alpha=0.05). The QTH LCU provided significantly higher (pcement showed lower Knoop hardness than the other shades for both LCUs and post-cure times.

Replacement of Co-base alloy for radiation exposure reduction in the primary system of PWR

International Nuclear Information System (INIS)

Han, Jeong Ho; Nyo, Kye Ho; Lee, Deok Hyun; Lim, Deok Jae; Ahn, Jin Keun; Kim, Sun Jin

1996-01-01

Of numerous Co-free alloys developed to replace Co-base stellite used in valve hardfacing material, two iron-base alloys of Armacor M and Tristelle 5183 and one nickel-base alloy of Nucalloy 488 were selected as candidate Co-free alloys, and Stellite 6 was also selected as a standard hardfacing material. These four alloys were welded on 316SS substrate using TIG welding method. The first corrosion test loop of KAERI simulating the water chemistry and operation condition of the primary system of PWR was designed and fabricated. Corrosion behaviors of the above four kinds of alloys were evaluated using this test loop under the condition of 300 deg C, 1500 psi. Microstructures of weldment of these alloys were observed to identify both matrix and secondary phase in each weldment. Hardnesses of weld deposit layer including HAZ and substrate were measured using micro-Vickers hardness tester. The status on the technology of Co-base alloy replacement in valve components was reviewed with respect to the classification of valves to be replaced, the development of Co-free alloys, the application of Co-free alloys and its experiences in foreign NPPs, and the Co reduction program in domestic NPPs and industries. 18 tabs., 20 figs., 22 refs. (Author)

Effect of Coil Current on the Properties of Hydrogenated DLC Coatings Fabricated by Filtered Cathodic Vacuum Arc Technique

Science.gov (United States)

Liao, Bin; Ouyang, Xiaoping; Zhang, Xu; Wu, Xianying; Bian, Baoan; Ying, Minju; Jianwu, Liu

2018-01-01

We successfully prepared hydrogenated DLC (a-C:H) with a thickness higher than 25 μm on stainless steel using a filtered cathode vacuum arc (FCVA) technique. The structural and mechanical properties of DLC were systematically analyzed using different methods such as x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, Vickers hardness, nanohardness, and friction and wear tests. The effect of coil current on the arc voltage, ion current, and mechanical properties of resultant films was systematically investigated. The novelty of this study is the fabrication of DLC with Vickers hardness higher than 1500 HV, in the meanwhile with the thickness higher than 30 μm through varying the coil current with FCVA technique. The results indicated that the ion current, deposition rate, friction coefficient, and Vickers hardness of DLC were significantly affected by the magnetic field inside the filtered duct.

Influence of wearing latex gloves on electric pulp tester readings in children.

Science.gov (United States)

Holan, G

1993-12-01

Electric pulp testers operated by completing an electric circuit. Latex examination gloves have been claimed to interrupt this circuit and lead to false-negative results. This study was conducted to evaluate the influence of wearing latex gloves on electric pulp tester (EPT) readings. The pulps of 80 maxillary permanent incisors of 22 children 10-13 1/2 years old were tested using the Pelton & Crane 'Vitapulp' instrument. Each tooth was tested twice: with gloves and with bare hands. Teeth failing to respond to the EPT without gloves were excluded from the study. All EPT readings ranged between 1 and 9.5. Five teeth gave the same responses with gloved and ungloved hands. Only five teeth did not respond when gloves were worn, and all of these gave readings near the top of the EPT scale when tested without gloves. The other 70 teeth presented significantly higher readings with gloves than without gloves. It is concluded that removal of examination gloves during the operation of the EPT is necessary only if no response is obtained.

Sandia's severe human body Electrostatic Discharge Tester (SSET)

International Nuclear Information System (INIS)

Barnum, J.R.

1991-01-01

This paper reports that the Electromagnetic Testing Division at Sandia National Laboratories (SNL) has developed a simulator to replicate a severe human body electrostatic discharge event. This simulator is referred to as Sandia's Severe Human Body Electrostatic Discharge Tester (SSET). The SSET is configured as a coaxial transmission line, which allows control of parasitic inductance and capacitance to achieve the desired waveform signature, and operates reliably at voltages up to 35 kV. It is constructed from off-the-shelf or easily fabricated components and costs approximately $750 for materials, not including the power supply. The output is very repeatable and provides good simulation fidelity of a severe human body discharge

A measuring system for mechanical characterization of thin films based on a compact in situ micro-tensile tester and SEM moiré method

International Nuclear Information System (INIS)

Li, Yanjie; Tang, Minjin; Xie, Huimin; Zhu, Ronghua; Luo, Qiang; Gu, Changzhi

2013-01-01

A measuring system for mechanical characterization of thin films based on a compact in situ micro-tensile tester and scanning electron microscope (SEM) moiré method is proposed. The load is exerted by the tensile tester and the full field strain is measured by SEM moiré method. The configuration of the tensile tester and the principle of SEM moiré method are introduced. In the tensile tester, a lever structure is designed to amplify the displacement imposed by lead–zirconate–titanate (PZT) actuator. The SEM moiré method is applied to measure the strain of the thin film, including both the average strain in the gage section and the local strain distribution at a specific region. As an application, the measuring system is applied to characterize the mechanical property of the free-standing aluminum thin film. The experimental results demonstrate the feasibility of the system and its good application potential for mechanical behavior analysis of film-like materials. (paper)

The validity and intra-tester reliability of markerless motion capture to analyse kinematics of the BMX Supercross gate start.

Science.gov (United States)

Grigg, Josephine; Haakonssen, Eric; Rathbone, Evelyne; Orr, Robin; Keogh, Justin W L

2017-11-13

The aim of this study was to quantify the validity and intra-tester reliability of a novel method of kinematic measurement. The measurement target was the joint angles of an athlete performing a BMX Supercross (SX) gate start action through the first 1.2 s of movement in situ on a BMX SX ramp using a standard gate start procedure. The method employed GoPro® Hero 4 Silver (GoPro Inc., USA) cameras capturing data at 120 fps 720 p on a 'normal' lens setting. Kinovea 0.8.15 (Kinovea.org, France) was used for analysis. Tracking data was exported and angles computed in Matlab (Mathworks®, USA). The gold standard 3D method for joint angle measurement could not safely be employed in this environment, so a rigid angle was used. Validity was measured to be within 2°. Intra-tester reliability was measured by the same tester performing the analysis twice with an average of 55 days between analyses. Intra-tester reliability was high, with an absolute error <6° and <9 frames (0.075 s) across all angles and time points for key positions, respectively. The methodology is valid within 2° and reliable within 6° for the calculation of joint angles in the first ~1.25 s.

Influence of light-curing units and restorative materials on the micro hardness of resin cements

Directory of Open Access Journals (Sweden)

Kuguimiya Rosiane

2010-01-01

Full Text Available Aim: The aim of this study was to evaluate the effect of indirect restorative materials (IRMs and light-curing units (LCUs on the micro hardness of dual-cured resin cement. Materials and Methods: A total of 36 cylindrical samples (2 mm thick were prepared with dual-cured resin cement (Relyx ARC photo-activated with either a QTH (Optilight Plus for 40s or a LED (Radii light-curing unit for 65s. Photo-activation was performed through the 2-mm- thick IRMs and the samples were divided into six groups (n=6 according to the combination of veneering materials (without, ceramic and indirect resin and LCUs (QTH and LED. In the control group, the samples were light-cured with a QTH unit without the interposition of any restorative material. Vickers micro hardness test was performed on the top and bottom surfaces of each sample (load of 50 g for 15 secs. The data were statistically analyzed using a three-way ANOVA followed by Tukey x s post-hoc test ( P < 0.05. Results: There were no statistically significant differences on the top surface between the light curing-units ( P > 0.05; however, the LED provided greater hardness on the bottom surface when a ceramic material was used ( P < 0.05. The mean hardness in photo-activated samples, in which there was no interposition of indirect materials, was significantly greater ( P < 0.01. Conclusions: It may be concluded that the interposition of the restorative material decreased the micro hardness in the deeper cement layer. Such decrease, however, was lower when the ceramic was interposed and the cement light-cured with LED.

Diamond-like carbon coatings enhance the hardness and resilience of bearing surfaces for use in joint arthroplasty.

Science.gov (United States)

Roy, M E; Whiteside, L A; Xu, J; Katerberg, B J

2010-04-01

The purpose of this study was to evaluate the potential of a hard diamond-like carbon (DLC) coating to enhance the hardness and resilience of a bearing surface in joint replacement. The greater hardness of a magnesium-stabilized zirconium (Mg-PSZ) substrate was expected to provide a harder coating-substrate composite microhardness than the cobalt-chromium alloy (CoCr) also used in arthroplasty. Three femoral heads of each type (CoCr, Mg-PSZ, DLC-CoCr and DLC-Mg-PSZ) were examined. Baseline (non-coated) and composite coating/substrate hardness was measured by Vickers microhardness tests, while nanoindentation tests measured the hardness and elastic modulus of the DLC coating independent of the Mg-PSZ and CoCr substrates. Non-coated Mg-PSZ heads were considerably harder than non-coated CoCr heads, while DLC coating greatly increased the microhardness of the CoCr and Mg-PSZ substrates. On the nanoscale the non-coated heads were much harder than on the microscale, with CoCr exhibiting twice as much plastic deformation as Mg-PSZ. The mechanical properties of the DLC coatings were not significantly different for both the CoCr and Mg-PSZ substrates, producing similar moduli of resilience and plastic resistance ratios. DLC coatings greatly increased hardness on both the micro and nano levels and significantly improved resilience and resistance to plastic deformation compared with non-coated heads. Because Mg-PSZ allows less plastic deformation than CoCr and provides a greater composite microhardness, DLC-Mg-PSZ will likely be more durable for use as a bearing surface in vivo. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

First-principle calculations on the structural and electronic properties of hard C11N4

International Nuclear Information System (INIS)

Li, Dongxu; Shi, Jiancheng; Lai, Mengling; Li, Rongkai; Yu, Dongli

2014-01-01

A graphite-like C 11 N 4 model was built by stacking graphene and a C 3 N 4 triazine layer and simulated by first principle calculations, which transfers to a diamond-like structure under high pressure. The structural, mechanical, and electronic properties of both materials were calculated. The elastic constants of both materials satisfy the Born-criterion. Furthermore, no imaginary frequencies were observed in phonon calculations. The diamond-like C 11 N 4 is semiconducting and consists of polyhedral and hollow C–N cages. The Vickers hardness of diamond-like C 11 N 4 was calculated to be 58 GPa. The phase transformation from graphite-like to diamond-like C 11 N 4 is proposed to occur at approximately 27.2 GPa based on the pressure-dependent enthalpy

Effect of storage in water and thermocycling on hardness and roughness of resin materials for temporary restorations

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Jerusa Cleci de Oliveira

2010-09-01

Full Text Available PURPOSE: This study evaluated the effect of storage in water and thermocycling on hardness and roughness of resin materials for temporary restorations. MATERIAL AND METHODS: Three acrylic resins (Dencor-De, Duralay-Du, and Vipi Cor-VC were selected and one composite resin (Opallis-Op was used as a parameter for comparison. The materials were prepared according to the manufacturers' instructions and were placed in stainless steel moulds (20 mm in diameter and 5 mm thick. Thirty samples of each resin were made and divided into three groups (n = 10 according to the moment of Vickers hardness (VHN and roughness (Ra analyses: C (control group: immediately after specimen preparation; Sw: after storage in distilled water at 37 °C for 24 hours; Tc: after thermocycling (3000 cycles; 5-55 °C, 30 seconds dwell time. Data were submitted to 2-way ANOVA followed by Tukey's test (α = 0.05. RESULTS: Op resin had higher surface hardness values (p 0.05 in roughness among materials (De = 0.31 ± 0.07; Du = 0.51 ± 0.20; VC = 0.41 ± 0.15; Op = 0.42 ± 0.18. Storage in water did not change hardness and roughness of the tested materials (p > 0.05. There was a significant increase in roughness after thermocycling (p < 0.05, except for material Du, which showed no significant change in roughness in any evaluated period (p = 0.99. CONCLUSION: Thermocycling increased the roughness in most tested materials without affecting hardness, while storage in water had no significant effect in the evaluated properties.

Development of new design mechanical seal tester for Primary Loop Recirculation Pump (PLR Pump)

International Nuclear Information System (INIS)

Fukushima, Naoki; Koshiba, Koremutsu

1995-01-01

The mechanical seal for a Primary Loop Recirculation Pump (PLR Pump) is an important part of a BWR plant. This study describes a new mechanical seal tester developed to certify mechanical seal performance before installation in a PLR Pump on site. (author)

Initial Development of an Electronic Testis Rigidity Tester

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Petros Mirilas

2011-01-01

Full Text Available We aimed to develop our previously presented mechanical device, the Testis Rigidity Tester (TRT, into an electronic system (Electronic Testis Rigidity Tester, ETRT by applying tactile imaging, which has been used successfully with other solid organs. A measuring device, located at the front end of the ETRT incorporates a tactile sensor comprising an array of microsensors. By application of a predetermined deformation of 2 mm, increased pressure alters linearly the resistance of each microsensor, producing changes of voltage. These signals were amplified, filtered, and digitized, and then processed by an electronic collector system, which presented them as a color-filled contour plot of the area of the testis coming into contact with the sensor. Testis models of different rigidity served for initial evaluation of ETRT; their evacuated central spaces contained different, increasing glue masses. An independent method of rigidity measurement, using an electric weight scale and a micrometer, showed that the more the glue injected, the greater the force needed for a 2-mm deformation. In a preliminary test, a single sensor connected to a multimeter showed similar force measurement for the same deformation in these phantoms. For each of the testis models compressed in the same manner, the ETRT system offered a map of pressures, represented by a color scale within the contour plot of the contact area with the sensor. ETRT found certain differences in rigidity between models that had escaped detection by a blind observer. ETRT is easy to use and provides a color-coded “insight“ of the testis internal structure. After experimental testing, it could be valuable in intraoperative evaluation of testes, so that the surgeon can decide about orchectomy or orcheopexy.

High hardness-high toughness WC-20Co nanocomposites: Effect of VC variation and sintering temperature

International Nuclear Information System (INIS)

Kumar, Devender; Singh, K.

2016-01-01

WC-Co nanocomposites with variable VC content are synthesized by liquid phase sintering at two different temperatures. The as synthesized samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and optical microscope. The mechanical properties are obtained by Vickers indentation method. The high content of VC, lead to high porosity when sintering temperature is increased from 1350 to 1400 °C. The relative density of all the samples is more than 95%. Microstructure reveals that agglomeration of W-Co-C and V-W-C increases at 1400 °C, which generates layered interfaces in radial direction and hence the material inhomogeneity. XRD pattern shows that the formation of η phase increases at 1400 °C, which is responsible to decrease the fracture toughness of the present samples. The average particle size of 102 nm, highest hardness of 1870.6 kgf/mm"2 with fracture toughness of 14.4 MN/mm"3"/"2 is observed in sample having 7.5 wt% VC, sintered at 1350 °C for one minute. This combination shows the highest hardness and reasonably high toughness as compared to conventionally sintered materials reported so far.

Evaluation of mechanical hardness and fracture toughness of Co and Al co-doped ZnO

International Nuclear Information System (INIS)

Siddheswaran, R.; Mangalaraja, R.V.; Avila, Ricardo E.; Manikandan, D.; Esther Jeyanthi, C.; Ananthakumar, S.

2012-01-01

Combustion synthesized nanocrystalline Co and Al co-doped ZnO powders [(Zn 1−x−y Co x Al y O; x=0.04, 0.03, 0.02; y=0.01, 0.02, 0.03)] were fabricated into cylindrical discs by uni-axial pressing and sintered intentionally at 1000 °C for 2 h to assess the mechanical performance. The crystallinity of the pure and doped ZnO was confirmed by X-ray diffraction analysis. The microstructures of the sintered samples were investigated by scanning electron microscopy (SEM) to examine the density, porosity, grain size and its distribution. Grains of 0.5–3 μm were observed for the samples sintered at 1000 °C. The mechanical properties such as micro-hardness, fracture toughness and strain hardening co-efficient were investigated by the Vickers indentation method. It was found that the crack mode observed during the indentation on the samples belongs to median cracks under a load of 19.6 N. Also, the hardness was enhanced with increasing mol% of Co, while the trend was reversed with the increase of Al content. In addition, the strain hardening coefficient and fracture toughness were calculated using the indentation data.

Evaluation of Next-Generation Vision Testers for Aeromedical Certification of Aviation Personnel

Science.gov (United States)

2009-07-01

measure distant, intermediate, and near acuity. The slides are essentially abbreviated versions of the Early Treatment for Diabetic Retinopathy Study...over, requiring intermediate vision testing and 12 were color deficient. Analysis was designed to detect statistically significant differences between...Vertical Phoria (Right & Left Hyperphoria) Test scores from each of the vision testers were collated and analyzed. Analysis was designed to detect

Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure

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T.S. Yang

2018-01-01

Full Text Available Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating.

Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure.

Science.gov (United States)

Yang, T S; Yao, S H; Chang, Y Y; Deng, J H

2018-01-08

Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating.

The effect of Coca-Cola and fruit juices on the surface hardness of glass-ionomers and 'compomers'.

Science.gov (United States)

Aliping-McKenzie, M; Linden, R W A; Nicholson, J W

2004-11-01

The interaction of tooth-coloured dental restorative materials (a conventional glass-ionomer, two resin-modified glass-ionomers and two compomers) with acidic beverages has been studied with the aim of investigating how long-term contact affects solution pH and specimen surface hardness. For each material (ChemFil Superior, ChemFlex, Vitremer Core Build-Up/Restorative, Fuji II LC, Dyract AP and F2000) disc-shaped specimens were prepared and stored in sets of six in the following storage media: 0.9% NaCl (control), Coca-Cola, apple juice and orange juice. After time intervals of 1 day, 1 week, 1 month, 3 months, 4 months, 6 months and 1 year, solution pH and Vickers Hardness Number were determined for each individual specimen. Differences were analysed by anova followed by Student-Newman-Keuls post hoc analysis. All materials were found to reduce the pH of the 0.9% NaCl, but to increase the pH of the acidic beverages. The conventional glass-ionomers dissolved completely in apple juice and orange juice, but survived in Coca-Cola, albeit with a significantly reduced hardness after 1 year. The other materials survived in apple juice and orange juice, but showed greater reductions in surface hardness in these beverages than in Coca-Cola. Fruit juices were thus shown to pose a greater erosive threat to tooth coloured materials than Coca-Cola, a finding which is similar to those concerning dentine and enamel towards these drinks.

Impact of X-ray irradiation on PMMA thin films

International Nuclear Information System (INIS)

Iqbal, Saman; Rafique, Muhammad Shahid; Anjum, Safia; Hayat, Asma; Iqbal, Nida

2012-01-01

Highlights: ► PMMA thin films were deposited at 300 °C and 500 °C using PLD technique. ► These films were irradiated with different fluence of laser produced X-rays. ► Irradiation affects the ordered packing as well as surface morphology of film. ► Hardness of film decreases up to certain value of X-ray fluence. ► Absorption in UV–visible range exhibits a non linear behavior. - Abstract: The objective of this project is to explore the effect of X-ray irradiation of thin polymeric films deposited at various substrate temperatures. pulsed laser deposition (PLD) technique is used for the deposition of PMMA thin films on glass substrate at 300 °C and 500 °C. These films have been irradiated with various X-rays fluences ranging from 2.56 to 5.76 mJ cm −2 . Characterization of the films (before and after the irradiation) is done with help of X-ray Diffractrometer, Optical Microscope, Vickers hardness tester and UV–vis spectroscopy techniques. From XRD data, it is revealed that ordered packing has been improved for the films deposited at 300 °C. However after irradiation the films exhibited the amorphous behavior regardless of the X-ray fluence. Film deposited at 500 °C shows amorphous structure before and after irradiation. Hardness and particle size of thin film have also increased with the increasing substrate temperature. However, the irradiation has reverse effect i.e. the particle size as well as the hardness has reduced. Irradiation has also enhanced the absorption in the UV–visible region.

Mechanical Properties and Wear Characteristics Al-ZrO2-SiCp and Graphite Hybrid Metal Matrix Composites

Science.gov (United States)

Nayak, S. K.; Mahanta, T.; Sahoo, J. K.; Mishra, A.

2018-03-01

Development of Aluminum Metal Matrix Co mposites (AMMCs) has been one of the major requirements in engineering applicat ions due to their excellent mechanical properties, light weight and high strength. In the present investigation, Stir casting technique has been used for fabrication of co mposites, taking Alu miniu m as parent metal, Silicon Carbide (SiCp) of 7 vol. % of 220 mesh size and 1.75 vol. % of graphite as reinforcements. The Zirconia content was varied as 2.75, 4.5 and 6 vol. % to fabricate three d ifferent types of hybrid composites. The tensile strength and hardness were measured in UTM and Vickers hardness tester respectively and the wear characteristics were studied in a pin on disc friction monitor under dry sliding condition against steel counter face. The tensile strength was found to be 90 MPa, 120 MPa, 130 MPa and hardness 80.25 VHN, 103.22 VHN, 103.77 VHN for 2.75, 4.5 and 6vol. % of Zirconia respectively. Fro m the above investigation, it is recommended that composition with Al, 7 %-SiCp, 1.75 % -Gr and 6 vol %-ZrO2 showed better mechanical p roperties i.e . h igh tensile strength (130MPa) and reasonably good hardness (103.77 VHN) . The co mposite with Al, 7 % - SiCp, 1.75 % -Gr and 6 %-ZrO2 is good for short run frictional applicat ion and the composite with Al, 7 %- SiCp, 1.75 % -Gr and 4.5 %- ZrO2 may be used for long run frictional applicat ions after testing.

A new non-destructive method for estimating the remanent life of a turbine rotor steel by reversible magnetic permeability

International Nuclear Information System (INIS)

Ryu, K.S.; Nahm, S.H.; Park, J.S.; Yu, K.M.; Kim, Y.B.; Son, D.

2002-01-01

We present a new magnetic and non-destructive procedure to evaluate the remanent life of 1Cr-1Mo-0.25V steel using the value of reversible magnetic permeability. The method is based on the existence of reversible magnetic permeability in the differential magnetization around the coercive force. The measurement principle is based on the foundation harmonics voltage induced in a coil using a lock-in amplifier tuned to a frequency of the exciting one. Results obtained for reversible magnetic permeability and Vickers hardness on the aged sample show that the peak interval of reversible magnetic permeability (PIRMP) and Vickers hardness decreases as aging time increases. A softening curve is obtained from the correlation between Vickers hardness and the PIRMP. This curve can be used as a non-destructive method to evaluate the remanent life of 1Cr-1Mo-0.25V steel

Effect of ion nitridation process on hardness and the corrosion resistance of biomaterials

International Nuclear Information System (INIS)

Wirjoadi; Lely Susita; Bambang Siswanto; Sudjatmoko

2012-01-01

Ion nitriding process has been performed on metal biomaterials to improve their mechanical properties of materials, particularly to increase hardness and corrosion resistance. This metallic biomaterials used for artificial bone or a prosthetic graft and used as devices of orthopedic biomaterials are usually of 316L SS metal-type and Ti-6Al-4V alloy. The purpose of this study is to research the development and utilization of ion nitridation method in order to get iron and titanium nitride thin films on the metallic biomaterials for artificial bone that has wear resistance and corrosion resistance is better. Microhardness of the samples was measured using a microhardness tester, optimum hardness of SS 316L samples are about 582 VHN, this was obtained at the nitriding temperature of 500 °C, the nitriding time of 3 hours and the nitrogen gas pressure of 1.6 mbar, while optimum hardness of Ti-6Al-4V alloy is 764 VHN, this was obtained at the nitriding temperature of 500 °C, the nitriding time of 4 hours and the nitrogen gas pressure of 1.6 mbar. The hardness value of SS 316L sample and Ti-6Al-4V alloy increase to 143% and 153%, if compared with standard samples. The optimum corrosion resistance at temperature of 350 °C for SS 316L and Ti-6Al-4V are 260,12 and 110,49 μA/cm 2 or corrosion rate are 29,866 and 15,189 mpy, respectively. (author)

Use of variations in unit cell length, reflectance and hardness for determining the origin of Fe disulphides in sedimentary rocks

Science.gov (United States)

Dill, H. G.; Eberhard, E.; Hartmann, B.

1997-01-01

Fe disulphides are common opaque accessories in sedimentary rocks. Both marcasite and pyrite may shed some light on the depositional environment and help determine the diagenesis of their host rocks. Quantitative ore microscopy (reflectance measurements, Vickers hardness numbers) and X-ray diffraction methods, supplemented with scanning electron microscopy and chemical analyses, were applied to pyrite (and some marcasite) hosted by sedimentary rocks spanning the interval from the Devonian to the Pliocene, and formed in various marine and continental environments. Quantitative ore microscopy of pyrites of sedimentary origin does not seem to be an efficient tool for analyzing the environment owing to the inhomogeneous nature of sulphide aggregates when viewed under the ore microscope, and the variable amounts of minor elements (e.g., As, Ni, and Co) that control the reflectance values (RV) and Vickers hardness numbers (VHN) of the host sulphides. However, such parameters as crystal habit and unit cell length of pyrite, which correlate with FeS x, are useful for environmental analysis. The redox conditions and the presence of organic remains during formation are the main factors determining these crystallographic parameters. Differences in these parameters from those of pure, ideal FeS 2 can be related to substitution of, e.g., wustite in the pyrite lattice, reflecting moderate oxidation (i.e. in the microenvironment). As far as crystal habit and length of the cell edge are concerned, late stage diagenesis is obviously less important than the microenvironment attending initial formation. The environment of deposition (i.e. the macroenvironment) of pyrite-bearing rocks has no influence on the crystal morphology or the length of the unit cell of Fe disulphide. X-ray diffraction measurements demonstrate that this method provides useful evidence on the microenvironment of sulphide precipitation around a single, equant pyrite, as well as around pyritized fossils.

Influence of Scanning Speed on the Microhardness Property of Additive Manufactured Titanium Alloy

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R. M. Mahamood

2016-12-01

Full Text Available Ti6Al4V is an important aerospace alloy, and it is challenging processing this material through traditional manufacturing processes. Laser metal deposition, an additive manufacturing process offers lots of advantages for processing aerospace materials, the ability to increase buy-to-fly ratio by at least 80% amongst other things. An improved property is achievable through laser metal deposition. The Ti6Al4V powder of particle size 150-200 μm was deposited using a 4.0 kW Rofin Sinar Nd: YAG laser on 72x72x5 mm Ti6Al4V substrate. The powder was delivered using argon gas as a shield. The scanning speed was varied between 0.01 and 0.12 m/sec. The microstructures of the deposited layers were studied by optical microscope and the microhardness was also measured using the Vickers hardness tester. The properties of the deposited tracks were compared to that of the substrate. The microhardness was found to increase with increase in scanning speed.

Effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness: An in vitro study

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Gaurao Vasant Mali

2015-01-01

Full Text Available Objectives: To assess and compare the effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness over a period of 14 days. Materials and Methods: An in vitro study was done on 40 noncarious deciduous teeth. 10 teeth in each group were dipped in 4 pediatric medicinal syrups (1 sugarfree and 3 conventional for 1 min thrice daily for 14 days and the enamel surface micro hardness was checked at baseline, 7 th day and 14 th day by Vickers hardness testing machine. The pH, titratable acidity and buffering capacity of the syrups were assessed. Results: The pH of syrups were above critical pH for demineralization of the tooth but tiratable acidity and buffering capacity differed. ANOVA test indicated that the reduction in mean micro hardness was maximum in Group D (Conventional Analgesic syrup and least in Group A (Sugarfree cough syrup on 7 th and 14 th day. On intergroup comparison there was no difference (P > 0.05 in micro hardness between Group B (Conventional Cough syrup and Group C (Conventional Antibiotic. However, highly significant (P < 0.01 difference between the either pair of Group B with Group D, and Group C with Group D on 14 th day. The percentage reduction in micro hardness on 14 th day was maximum for Group D (24.4 ± 2.2 and minimum for Group A (14.0 ± 1.3 which was statistically significant (P < 0.01. Conclusion: Sugar free pediatric medicines can be effective in reducing dental erosion and efforts should be made to incorporate sugar substitutes in formulation of pediatric medicines.

Development of a hard microcontroller

International Nuclear Information System (INIS)

Measel, P.R.; Sivo, L.L.; Quilitz, W.E.; Davidson, T.K.

1976-01-01

The applicability of commercially available microprocessors to certain systems requiring radiation survival was assessed. A microcontroller was designed and built to perform a monitor and control function of military operational ground equipment, and demonstrated to exceed the radiation hardness goal. The preparation of the microcontroller module required hardware and software design, selection of LSI and other piece part types, development of piece part and module electrical and radiation test techniques, and the performance of radiation tests on the LSI piece parts and the completed module. The microcontroller has a 16-bit central processor unit, a 4096 word read only memory, and a 256 word read-write memory. The module has circumvention circuitry, including a PIN diode radiation detector. The processor device used was the MMI 6701 T 2 L Schottky bipolar 4-bit slice. Electrical exerciser circuits were developed for in-situ electrical testing of microprocessors and memories during irradiation. A test program was developed for a Terradyne J283 microcircuit tester for more complete electrical characterization of the MMI 6701 microprocessor. A simple self-test algorithm was used in the microcontroller for performance testing during irradiation. For the operational demonstration of the microcontroller a TI 960A minicomputer was used to provide the required complex inputs to the module and verify the module outputs

Effect of PWHT on Microstructure, Mechanical and Corrosion Behaviour of Gas Tungsten Arc Welds of IN718 Superalloys

Science.gov (United States)

Dilkush; Mohammed, Raffi; Madhusudhan Reddy, G.; Srinivasa Rao, K.

2018-03-01

The present work aims to improve corrosion resistance and mechanical behavior of the welds with suitable post weld heat treatment i.e. direct aging and solutionizing treatments (980STA, 1080STA). Gas tungsten arc welding (GTAW) has been performed on Inconel 718 (IN718) nickel based super alloy plates with 3mm thickness. The structural –property relationship of the post weld heat treated samples is judged by correlating the microstructural changes with observed mechanical behavior and pitting corrosion resistance of the welds As-recevied, direct aging (DA), 980STA,1080STA were studied. Welds were characterized for microstructure changes with scanning electron microscopy (SEM) and optical microscopy (OM).Vickers micro- hardness tester was used to measure the hardness of the weldments. Potential-dynamic polarization testing was carried out to study the pitting corrosion resistance in 3.5%NaCl (Sodium chloride) solution at 30°C.Results of the present study established that post weld heat treatments resulted in promoting the element segregation diffusion and resolve them from brittle laves particles in the matrix. Increased precipitation of strengthening phases lead to a significant increase in fusion zone hardness of 1080STA post weld heat treated condition compared to as welded, direct aged, 980STA conditions. Due to significant changes in the microstructural behavior of 1080STA condition resulted in superior pitting corrosion resistance than 980STA, direct aged and as- recevied conditions of IN718 GTA welds

Excellent durability of DLC film on carburized steel (JIS-SCr420) under a stress of 3.0 GPa

International Nuclear Information System (INIS)

Yakabe, F; Kumagai, M; Kuwahara, H; Ochiai, S; Jinbo, Y; Horiuchi, T

2008-01-01

To improve durability of transmission gears, Diamond Like Carbon (DLC) film coated on roller was estimated as well as TiN film. These films were coated on JIS-SCr420 steel, which was carburized, quenched, and tempered. DLC and TiN films were deposited by PCVD and PVD process, respectively. These surface modified rollers were estimated by usual metallurgical methods (observation of microstructure by optical microscope, SEM, and TEM, measurement of hardness by Vickers hardness tester and nano-indentator), measurement of friction coefficient by ball-on-disk in dry atmosphere, analysis of carbon by Raman spectroscopy and hydrogen by EDRA, and lifetime of pitting by the roller-pitting test. The hardness values were 21 GPa and 26 GPa, the elasticity coefficients were 192 GPa and 336 GPa, the friction coefficients were 0.1∼0.15 and 0.5∼0.6 for DLC and TiN films, respectively. The present DLC was a typical DLC called as hydrogenated amorphous carbon (a-C: H). The hydrogen content was about 20%. The surface fatigue resistance of DLC-coated specimen had 100 times longer life than that the carburized and quenched one even under Hertzian contact stress of 3.0 GPa. TiN coated specimen was failed at 3.0 GPa by 5.17·10 5 cycles despite that the strength of the surface of the substrate was reduced due to the exposure at higher temperature in the coating process than the temperature for tempering

Effect of complexing agents and pH on microstructure and tribological properties of Co-W coatings produced by double pulse electrodeposition

International Nuclear Information System (INIS)

Su Fenghua; Liu Cansen; Huang Ping

2012-01-01

The Co-W coatings were produced by double pulse electrodeposition from aqueous bath with cobalt sulphate and sodium tungstate. Effect of complexing agent and pH value in the plating bath on the microstructure, morphology and hardness of the electrodeposited Co-W coatings were investigated using an X-ray diffraction (XRD), scanning electron microscope (SEM) and a Vickers hardness tester, respectively. The friction and wear properties of the Co-W coatings deposited from different baths were evaluated with a ball-on-disk UMT-3MT tribometer. The correlation among the electrodepositing condition that varied with the complexing agent or pH value, the microstructure and the tribological properties of the deposited Co-W coatings were discussed. The results show that the complexing agent and pH value significantly affect the microstructure and tribological properties of the electrodeposited Co-W coatings. The sodium citrate is the best complexing agent to improve the tribological properties of the electrodeposited Co-W coatings at pH 6.0, followed by the sodium gluconate. The Co-W coatings electrodeposited from the near neutral bath can obtain better tribological properties than those deposited from strong acid or strong alkaline bath. The differences of the tribological properties for Co-W coatings from different baths were attributed to their different hardness, crystal structure and morphological characterizations, which can be optimized by the electrodepositing condition, i.e., the complexing agent and pH value in bath.

Evaluation of the surface hardness of composite resins before and after polishing at different times Avaliação da dureza superficial de resinas compostas antes e após o polimento em diferentes tempos

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Michelle Alexandra Chinelatti

2006-06-01

Full Text Available PURPOSE: The aim of this study was to evaluate the surface hardness of six composite resins: Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (microfilled and Z100 (minifilled before and after polishing at different times. MATERIALS AND METHODS: For this purpose, 240 specimens (5mm diameter, 1.4mm high were prepared. Vickers hardness was determined before and after polishing at different times: immediately, 24h, 7 and 21 days after preparation of the samples. Statistical analysis was performed by ANOVA and Tukey test. RESULTS: There was no difference in the hardness of flowable resins, which had lower hardness than the minifilled resin. The minifilled resin showed the highest surface hardness as compared to the other materials (pPROPOSIÇÃO: O objetivo deste estudo foi avaliar a dureza superficial de seis resinas compostas - Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (micropartículas e Z100 (híbrida - antes e após o polimento realizado em diferentes tempos. MATERIAL E MÉTODO: Foram confeccionados 240 corpos-de-prova circulares (5mm de diâmetro e 1,4mm de altura. A dureza Vickers foi obtida antes e após o polimento realizado em diferentes tempos: imediatamente, 24 horas, 7 dias e 21 dias após a confecção do corpo-de-prova. Os dados foram analisados estatisticamente por meio da ANOVA e do Teste de Tukey. RESULTADOS: Não houve diferença entre as resinas compostas flowable, as quais apresentaram os menores valores de dureza. A resina composta híbrida demonstrou os melhores resultados. Todos os materiais exibiram aumento de dureza após a realização do polimento, que foi mais evidente após 7 dias. CONCLUSÃO: Pôde-se concluir que, independente do tipo de resina composta, a dureza superficial foi consideravelmente maior quando o polimento foi realizado 1 semana após a confecção dos corpos-de-prova.

Correlation between yield stress and hardness of nickel–silicon–boron-based alloys by nanoindentation

International Nuclear Information System (INIS)

Şerban, Viorel-Aurel; Codrean, Cosmin; Vodă, Mircea; Chicot, Didier; Decoopman, Xavier

2014-01-01

Based on the relation proposed by Tabor in 1951, which connects the ultimate tensile strength and the yield stress of classical materials to the Brinell or Vickers hardness numbers by a simple factor of proportionality, we propose an extended analytical model for the determination of the yield stress of brittle materials using nanoindentation data. This model considers the nanoindentation hardness calculated from the projected actual contact area between the indenter and the material which is representative of the real mean pressure exerted by the indenter compared to classical hardness numbers. A coefficient is introduced in the model to integrate the extent of the elastic recovery of the indented material occurring after the withdrawal of the indenter. This is possible by using the criterion defined by the residual to maximum indenter displacements ratio, this criterion being already related to the deformation mode under indentation. Indeed, this criterion allows identifying the piling-up deformation observed for complete or fully plastic deformation materials or the sinking-in deformation for purely elastic materials. The proposed model thus allows a good estimation of the yield stress of brittle materials for which classical tensile tests are not applicable. The model is validated on a variety of amorphous nickel–silicon-based alloy ribbons, i.e., Ni 89 Si 9 B 2 , Ni 78 Si 9 B 13 and Ni 68 Fe 3 Cr 7 Si 8 B 14 on which both nanoindentation tests and tensile experiments have been performed

Isotope Fuels Impact Tester (IFIT)

International Nuclear Information System (INIS)

Frantz, C.E.; Taylor, J.W.; Court, D.B.

1975-07-01

The Isotope Fuels Impact Tester (IFIT) is used for safely impacting 238 PuO 2 heat sources that have been heated to 2000 0 C. Impact velocities reach 300 m/s (1000 ft/s). A gas gun with a 178-mm (7-in.) bore is used to accelerate the heat source, which is heated by a furnace built into the projectile. Double containment of the impacted heat source is obtained by two vessels that are sealed directly to the gun muzzle. The impact occurs in the inner vessel, and parts of the projectile jam into and thereby close each vessel. The inner vessel, containing the impacted heat source, is removed from the gun and is placed inside a glovebox for disassembly and heat-source recovery. IFIT's modular structure makes it versatile and adaptable to many types of tests. Many applications have demonstrated its versatility and, more important, its capability for impacting 238 PuO 2 heat sources safely. An approximate theoretical relation is used to predict proper conditions for achieving desired impact velocities. Bore lubricants and projectile-seal design are also important for achieving proper impact velocities

Line tester analysis of yield and yield related attributed in different sunflower genotypes

International Nuclear Information System (INIS)

Din, S.U.; Khan, M.A.; Usman, K.; Sayal, O.U.

2014-01-01

This paper encompasses the study of line * tester analysis to chalk out genetic implications regarding yield and yield relating components in different genotypes of sunflower. Eight parents (four CMS lines and four restorers) along with their sixteen F1 hybrids were considered and planted in Randomized Complete Block Design (RCBD) replicated thrice at experimental area of Oilseed Research Program, National Agriculture Research Centre (NARC), Islamabad, Pakistan in 2011. Combining ability for some important morphological traits included days to flower initiation, days to flower completion, days to maturity, plant height, head diameter and seed yield plant-1. In this concern general combining ability (GCA), reciprocals combining ability (RCA) and specific combining ability (SCA) for all traits were studied. The GCA and SCA variances due to lines and testers interaction were significant for all the characters. However, the magnitude of GCAs from CMS lines (females) and restorers (pollinators) were higher than the SCA indicating preponderance of additive genes in the expression of all the traits. Among the lines, CMS-HA-54 whereas in testers, RHP-71, by manifesting maximum GCA effects were considered as the best general combiners for almost all the traits indicating the presence of more additive gene effects in these parents, therefore may serve as potential parents for hybridization and to improve the characters studied. Among the F1 hybrids, CMS HA-99 * RHP-76 (1.54, 212.65) and CMS HA-101 * RHP-73 (0.91, 432.73) were found as the best specific combiners for head or capitulum and seed yield. Hence, if farming community and researchers include these hybrids in their selection and hybridization program for the trait under study optimum result may be obtained. (author)

Portable tester for determining gas content within a core sample

Science.gov (United States)

Garcia, F. Jr.; Schatzel, S.J.

1998-04-21

A portable tester is provided for reading and displaying the pressure of a gas released from a rock core sample stored within a sealed container and for taking a sample of the released pressurized gas for chemical analysis thereof for subsequent use in a modified direct method test which determines the volume of gas and specific type of gas contained within the core sample. The portable tester includes a pair of low and high range electrical pressure transducers for detecting a gas pressure; a pair of low and high range display units for displaying the pressure of the detected gas; a selector valve connected to the low and high range pressure transducers and a selector knob for selecting gas flow to one of the flow paths; control valve having an inlet connection to the sealed container; and outlets connected to: a sample gas canister, a second outlet port connected to the selector valve means for reading the pressure of the gas from the sealed container to either the low range or high range pressure transducers, and a connection for venting gas contained within the sealed container to the atmosphere. A battery is electrically connected to and supplies the power for operating the unit. The pressure transducers, display units, selector and control valve means and the battery is mounted to and housed within a protective casing for portable transport and use. 5 figs.

Evaluation of bearing configurations using the single bearing tester in liquid nitrogen

Science.gov (United States)

Jett, T.; Hall, P.; Thom, R.

1991-01-01

Various bearing configurations were tested using the Marshall Space Flight Center single bearing tester with LN2 as the cryogenic coolant. The baseline was one Rocketdyne phase one high pressure oxidizer turbopump (HPOTP) pump end 45-mm bore bearing. The bearing configurations that were tested included a Salox/M cage configuration, a silicon nitride ball configuration, an elongated cage configuration, and a Bray 601 grease configuration.

Improvement of the Surface Hardness of Stainless Steel with the TitaniumCarbonitride Ti(CN) Thin Films

International Nuclear Information System (INIS)

Agus-Purwadi; Tri-Mardji Atmono; Widdi-Usada; Lely-Susita; Yunanto

2000-01-01

Fabrication of the T i (CN) thin films with methods of implantation and RFsputtering for improving the surfaces hardness of stainless steel (SS) hasbeen done. Some kinds of T i C thin films which made individually by varyingof RF sputtering power from 0 up to 160 watt are implanted by the nitrogenion beams on the doses and energy ion optimum of 6.107 x 10 17 ion/cm 2 and100 keV, also fabrication of T i (CN) thin films use RF sputtering method withT i target and reaction gases as argon, silene and nitrogen on the optimum ofsputtering parameter condition. The thin films yields are characterized byusing Microhardness Tester MX 170, obtained SS hardness which layered T i (CN)as 402.5 KHN from its initial of 215.54 KHN and 371.74 KHN (layered T i C), itmeans that the SS surface hardness improve 1.867 times cumulatively. From theX-Ray Diffraction (XRD) analysis yield showed that the microstructure ofT i (CN) films on the SS substrates are dominated by characteristic cubiccrystal structure with Miller plane orientation (111) on the scattering angleof 2 θ = 44 o . Morphology visualization of T i (CN) thin films crosssection on the SS substrate is realized by Spectroscopy Electron Microscope(SEM). (author)

A correlation between micro- and nano-indentation on materials irradiated by high-energy heavy ions

Science.gov (United States)

Yang, Yitao; Zhang, Chonghong; Ding, Zhaonan; Su, Changhao; Yan, Tingxing; Song, Yin; Cheng, Yuguang

2018-01-01

Hardness testing is an efficient means of assessing the mechanical properties of materials due to the small sampling volume requirement. Previous studies have established the correlation between flow stress and Vickers hardness. However, the damage layer produced by ions irradiation with low energy is too thin to perform Vickers hardness test, which is usually measured by nano-indentation. Therefore, it is necessary to correlate the Vickers hardness and nano-hardness for the convenience of assessing mechanical properties of materials under irradiation. In this study, various materials (pure nickel, nickel base alloys and oxide dispersion strengthened steel) were irradiated with high-energy heavy ions to different damage levels. After irradiation, micro- and nano-indentation were performed to characterize the change in hardness. Due to indentation size effect (ISE), the hardness was dependent of load or depth. Therefore, Nix-Gao model was used to obtain the hardness without ISE (Hv0 and Hnano_0). The determined Hv0 was plotted as a function of the corresponding Hnano_0, then a good linear relation was found between Vickers hardness and nano-hardness, and a coefficient was determined to be 81.0 ± 10.5, namely, Hv 0 = 81.0Hnano _ 0 (Hv0 with unit of kgf/mm2, Hnano_0 with unit of GPa). This correlation was based on the data from various materials, therefore it was independent of materials. Based on the established correlation and nano-indentation results, the change fraction in yield stress of Inconel 718 and pure Ni with ion irradiation was compared with that with neutron irradiation. The data of Inconel 718 with heavy ion irradiation was in good agreement with the data with neutron irradiation, which was a good demonstration for the validation of the established correlation. However, a distinctive difference in change fraction of yield stress was seen for pure Ni under heavy ion irradiation and neutron irradiation, which was attributed to the difference in samples

Surface roughness and hardness of a composite resin: influence of finishing and polishing and immersion methods

Directory of Open Access Journals (Sweden)

Ana Luísa Botta Martins de Oliveira

2010-09-01

Full Text Available This study evaluated the finishing and polishing effect on the surface roughness and hardness of the Filtek Supreme XT, in fluoride solutions. Specimens were prepared (n = 140 with half of the samples finished and polished with Super-Snap® disks. The experimental groups were divided according to the presence or absence of finishing and polishing and immersion solutions (artificial saliva, sodium fluoride solution at 0.05% - manipulated, Fluordent Reach, Oral B, Fluorgard. The specimens remained immersed in artificial saliva for 24 hours and were then subjected to initial analysis (baseline of surface roughness and Vickers microhardness. Next, they were immersed in different fluoride solutions for 1 min/day, for 60 days. Afterwards, a new surface roughness and microhardness reading was conducted. The data were submitted to a two-way ANOVA and Tukey's test (5% significance level. For the comparison of mean roughness and hardness at baseline and after 60 days, the paired Student t test was used. The results showed that the surface roughness and microhardness of the Filtek Supreme XT were influenced by the finishing and polishing procedure, independently of the immersion methods.

Evaluation of dampers using a resonance adhesion tester

Directory of Open Access Journals (Sweden)

Stanislav Koláček

2013-01-01

Full Text Available This paper describes the diagnostics of dampers using resonant adhesion tester. This kind of test is non-invasive and evaluation is based on the EUSAMA methodology. The main goals of this method were to practically measure and evaluate technical condition of the shock absorbers. However, this method does not measure only damper properties, but the whole axle, too. During measurements, one must take into account the fact that the results can be easily influenced by external factors. These include e.g. wrong tire pressure, different kind of shock absorbers, and tires. The actual testing revealed that the measurement results are also influenced by bad condition of the vehicle axles. If we eliminate all these draw-backs, dampers testing can be very accurate.

Infant Physical Attractiveness, Affect, Temperament, and Gender in Relation to Tester Behavior

OpenAIRE

Hart, Andrea D.

1996-01-01

Easily observable infant characteristics have been shown to influence others; perceptions of infant competence. This study examined the relation between infant characteristics and a tester's willingness to repeat opportunities for the infant to pass items during administration of a cognitive test. Results showed that infant physical attractiveness was related to lower elicited infant performance (the ratio of items initially failed). Positive affect was related to higher test scores. Because ...

Hardness and Wear Resistance of TiC-Fe-Cr Locally Reinforcement Produced in Cast Steel

Directory of Open Access Journals (Sweden)

Olejnik E.

2016-06-01

Full Text Available In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy, using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ball-on-disc wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the composite zone was five times lower than chromium white cast iron containing 20 % Cr.

Estimates of genetic parameters from line x tester mating design for some quantitative traits in upload cotton, gossypium hirsutum L

International Nuclear Information System (INIS)

Baloch, M.H.; Kumbher, M.B.; Jatoi, W.A.

2008-01-01

Combining abilities of cotton varieties were evaluated using a line x tester design with eight lines and 4 testers. Good performance combination was found between the varieties CRIS-134 and BH-147. The former was a good candidate for fibre length improvement and the latter, a good parent for yield improvement. The specific combining ability suggested that both additive and dominant genes controlled the characters. Hybrid performance per se may be used to predict the parental performance for specific combining ability and thus for hybrid crop development. (author)

Growth of Vanadium Carbide by Halide-Activated Pack Diffusion

DEFF Research Database (Denmark)

Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Dahl, Kristian Vinter

The present work investigates growth of vanadium carbide (VC) layers by the pack diffusion method on a Vanadis 6 tool steel. The VC layers were produced by pack diffusion at 1000°C for 1, 4 and 16 hours. The VC layers were characterized with optical and electron microscopy, Vickers hardness tests...... and X-ray diffraction. Homogeneous VC mono-phase layers with Vickers hardness of more than 2400 HV were obtained. Hardening and tempering of the vanadized Vanadis 6 steel did not affect the VC layers....

Effect of milling time and CNT concentration on hardness of CNT/Al2024 composites produced by mechanical alloying

International Nuclear Information System (INIS)

Pérez-Bustamante, R.; Pérez-Bustamante, F.; Estrada-Guel, I.; Licea-Jiménez, L.; Miki-Yoshida, M.; Martínez-Sánchez, R.

2013-01-01

Carbon nanotube/2024 aluminum alloy (CNT/Al 2024 ) composites were fabricated with a combination of mechanical alloying (MA) and powder metallurgy routes. Composites were microstructurally and mechanically evaluated at sintering condition. A homogeneous dispersion of CNTs in the Al matrix was observed by a field emission scanning electron microscopy. High-resolution transmission electron microscopy confirmed not only the presence of well dispersed CNTs but also needle-like shape aluminum carbide (Al 4 C 3 ) crystals in the Al matrix. The formation of Al 4 C 3 was suggested as the interaction between the outer shells of CNTs and the Al matrix during MA process in which crystallization took place after the sintering process. The mechanical behavior of composites was evaluated by Vickers microhardness measurements indicating a significant improvement in hardness as function of the CNT content. This improvement was associated to a homogeneous dispersion of CNTs and the presence of Al 4 C 3 in the aluminum alloy matrix. - Highlights: ► The 2024 aluminum alloy was reinforced by CNTs by mechanical alloying process. ► Composites were microstructural and mechanically evaluated after sintering condition. ► The greater the CNT concentration, the greater the hardness of the composites. ► Higher hardness in composites is achieved at 20 h of milling. ► The formation of Al 4 C 3 does not present a direct relationship with the milling time.

Mapping the structure, composition and mechanical properties of human teeth

International Nuclear Information System (INIS)

Low, I.M.; Duraman, N.; Mahmood, U.

2008-01-01

The structure-property relationship in human adult and baby teeth was characterised by grazing-incidence synchrotron radiation diffraction, optical and atomic-force microscopy, in addition to Vickers indentation. Similarities and differences between both types of teeth have been highlighted and discussed. Depth-profiling results indicated the existence of contrasting but distinct gradual changes in crystal disorder, phase abundance, crystallite size and hardness within the baby and adult enamel, thus confirming the graded nature of human teeth. When compared to the adult tooth, the baby enamel is softer, more prone to fracture, but has larger hydroxyapatite grains. Vickers hardness of the enamel was load-dependent but load-independent in the dentine. The use of a 'bonded-interface' technique revealed the nature and evolution of deformation-microfracture damage around and beneath Vickers contacts

Mapping the structure, composition and mechanical properties of human teeth

Energy Technology Data Exchange (ETDEWEB)

Low, I.M. [Materials Research Group, Department of Applied Physics, Curtin University of Technology, Perth, WA 6845 (Australia)], E-mail: j.low@curtin.edu.au; Duraman, N.; Mahmood, U. [Materials Research Group, Department of Applied Physics, Curtin University of Technology, Perth, WA 6845 (Australia)

2008-03-10

The structure-property relationship in human adult and baby teeth was characterised by grazing-incidence synchrotron radiation diffraction, optical and atomic-force microscopy, in addition to Vickers indentation. Similarities and differences between both types of teeth have been highlighted and discussed. Depth-profiling results indicated the existence of contrasting but distinct gradual changes in crystal disorder, phase abundance, crystallite size and hardness within the baby and adult enamel, thus confirming the graded nature of human teeth. When compared to the adult tooth, the baby enamel is softer, more prone to fracture, but has larger hydroxyapatite grains. Vickers hardness of the enamel was load-dependent but load-independent in the dentine. The use of a 'bonded-interface' technique revealed the nature and evolution of deformation-microfracture damage around and beneath Vickers contacts.

Surface properties of UV irradiated PC–TiO{sub 2} nanocomposite film

Energy Technology Data Exchange (ETDEWEB)

Jaleh, B., E-mail: bkjaleh@yahoo.com; Shahbazi, N.

2014-09-15

Highlights: • Production of PC–TiO{sub 2} nanocomposite films. • Fully characterization of PC–TiO{sub 2} nanocomposite films. • Influence of UV irradiation on surface properties and hardness of PC–TiO{sub 2} nanocomposite film. - Abstract: In this work, polycarbonate–TiO{sub 2} nanocomposite films were prepared with two different percentages. The structure of samples were studied by X-ray diffraction. Thermal stability of the nanocomposites was studied by thermogravimetric analysis (TGA). The polycarbonate and polycarbonate–TiO{sub 2} nanocomposite films were exposed by UV light at different irradiation times. The effects of UV irradiation on the surface properties of samples have been studied by different characterization techniques, viz. scanning electron microscopy (SEM), FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle measurement and Vickers microhardness tester. Hydrophilicity and surface energy of UV treated samples varied depending on UV irradiation time. TGA curves showed that nanocomposite films have higher resistance to thermal degradation compared to polycarbonate. XPS analysis shows that surface of samples become more oxidized due to UV irradiation. For nanocomposite film, the smallest contact angle was observed in association with the longest UV irradiation time. The contact angle significantly decreased from 90° to 12° after 15 h of UV irradiation. It is observed that the hardness of the nanocomposite films increases after UV irradiation.

Influences of the current density on the performances of the chrome-plated layer in deterministic electroplating repair

Science.gov (United States)

Xia, H.; Shen, X. M.; Yang, X. C.; Xiong, Y.; Jiang, G. L.

2018-01-01

Deterministic electroplating repair is a novel method for rapidly repairing the attrited parts. By the qualitative contrast and quantitative comparison, influences of the current density on performances of the chrome-plated layer were concluded in this study. The chrome-plated layers were fabricated under different current densities when the other parameters were kept constant. Hardnesses, thicknesses and components, surface morphologies and roughnesses, and wearability of the chrome-plated layers were detected by the Vickers hardness tester, scanning electron microscope / energy dispersive X-ray detector, digital microscope in the 3D imaging mode, and the ball-milling instrument with profilograph, respectively. In order to scientifically evaluate each factor, the experimental data was normalized. A comprehensive evaluation model was founded to quantitative analyse influence of the current density based on analytic hierarchy process method and the weighted evaluation method. The calculated comprehensive evaluation indexes corresponding to current density of 40A/dm2, 45A/dm2, 50A/dm2, 55A/dm2, 60A/dm2, and 65A/dm2 were 0.2246, 0.4850, 0.4799, 0.4922, 0.8672, and 0.1381, respectively. Experimental results indicate that final optimal option was 60A/dm2, and the priority orders were 60A/dm2, 55A/dm2, 45A/dm2, 50A/dm2, 40A/dm2, and 65A/dm2.

Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

KAUST Repository

Alfazazi, Adamu; Kuti, Olawole Abiola; Naser, Nimal; Chung, Suk-Ho; Sarathy, Mani

2016-01-01

The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate

Effects of /sup 60/Co gamma radiation damage and heat treatment on the electro-mechanical properties of some related lithium alumino-borosilicate glasses

Energy Technology Data Exchange (ETDEWEB)

Abou Sekkina, M.M.; Gohar, I.A.; Megahed, A.A. (Al-Azhar Univ., Tanta (Egypt). Faculty of Science; Cairo Univ., El Mansura (Egypt). Faculty of Science)

1985-01-01

Various samples of pure lithium alumino-borosilicate glasses have been prepared and annealed. Data have been taken on the temperature dependence of DC electrical conductivity and the activation energy for conduction was evaluated in each case. Vickers hardness data have also been obtained as a function of tempering temperature and time for all glass compositions. Co-ordinated explanations of the DC conductivity and Vickers hardness induced by ionizing radiation are put forward and the activation energy for the process of carrier liberation are evaluated for the first time.

Effect of Mo concentration and aging time on the magnetic and mechanical hardness of Fe-xMo-5Ni-0.05C alloys (x = 5, 8, 11 and 15 wt. (%

Directory of Open Access Journals (Sweden)

Mauro Carlos Lopes Souza

2009-01-01

Full Text Available Changes to the microestructure during thermal aging treatment at 610 ºC in Fe-xMo-5Ni-0.05C alloys were studied for different aging times with different Mo concentrations. The heat treatment at 610 ºC induces carbide precipitation into the metallic matrix near Fe2Mo phase. The X-ray diffraction studies revealed a more intense precipitation of α-FeMo, Fe3Mo, R(Fe63Mo37 phases and MoC, Fe2MoC carbides for the alloys containing 15 and 11% Mo, respectively. This work shows that hardness and coercive force changes are function of the molybdenum content and aging time variation. Vickers hardness and coercive force both increase with the increase of molybdenum content and reach maximum values at 4 and 1h of aging, respectively.

Micro-scale abrasive wear behavior of medical implant material Ti-25Nb-3Mo-3Zr-2Sn alloy on various friction pairs.

Science.gov (United States)

Wang, Zhenguo; Huang, Weijiu; Ma, Yanlong

2014-09-01

The micro-scale abrasion behaviors of surgical implant materials have often been reported in the literature. However, little work has been reported on the micro-scale abrasive wear behavior of Ti-25Nb-3Mo-3Zr-2Sn (TLM) titanium alloy in simulated body fluids, especially with respect to friction pairs. Therefore, a TE66 Micro-Scale Abrasion Tester was used to study the micro-scale abrasive wear behavior of the TLM alloy. This study covers the friction coefficient and wear loss of the TLM alloy induced by various friction pairs. Different friction pairs comprised of ZrO2, Si3N4 and Al2O3 ceramic balls with 25.4mm diameters were employed. The micro-scale abrasive wear mechanisms and synergistic effect between corrosion and micro-abrasion of the TLM alloy were investigated under various wear-corrosion conditions employing an abrasive, comprised of SiC (3.5 ± 0.5 μm), in two test solutions, Hanks' solution and distilled water. Before the test, the specimens were heat treated at 760°C/1.0/AC+550°C/6.0/AC. It was discovered that the friction coefficient values of the TLM alloy are larger than those in distilled water regardless of friction pairs used, because of the corrosive Hanks' solution. It was also found that the value of the friction coefficient was volatile at the beginning of wear testing, and it became more stable with further experiments. Because the ceramic balls have different properties, especially with respect to the Vickers hardness (Hv), the wear loss of the TLM alloy increased as the ball hardness increased. In addition, the wear loss of the TLM alloy in Hanks' solution was greater than that in distilled water, and this was due to the synergistic effect of micro-abrasion and corrosion, and this micro-abrasion played a leading role in the wear process. The micro-scale abrasive wear mechanism of the TLM alloy gradually changed from two-body to mixed abrasion and then to three-body abrasion as the Vickers hardness of the balls increased. Copyright �

Results of the new eddy current tester for steam generator applications

International Nuclear Information System (INIS)

Ribes, B.; Hernandez, J.; Barcenilla, V.

2006-01-01

As a result of the recent developing line of eddy current data acquisition systems a new product comes to the market named Teddy+. With only 4 kg of weight constitutes a great advance with regards to the equipments used for this type of inspections available in the market. This advances, have enabled, among others, to increase considerably the S/N ratio, avoid typical saturation problems in the eddy current signal, increase the inspection speed, eliminate the reference probe, detect the air/tube signal in real time, together with the possibility to integrate the tester inside the pusher thanks to its reduced size and to have integrated the mechanical systems control board as part of the tester. The software application in charge of data acquisition and analysis has been optimized making it possible a faster and efficient data access, incorporating a new tool to allow a data quality control on-line, which has accelerated the detection process of non-valid registers. The processes related with the supervision of different analysis have been automated enabling a simultaneous comparison of up to four different analysis types. At the same time the necessary tools to make the successive passes of the resolution process have been included in the analysis software according to EPRI guidelines. These innovations and improvements place the new SG inspection system from TECNATOM, as one of the most powerful and reliable existing in the market (orig.)

Work Hard / Play Hard

OpenAIRE

Burrows, J.; Johnson, V.; Henckel, D.

2016-01-01

Work Hard / Play Hard was a participatory performance/workshop or CPD experience hosted by interdisciplinary arts atelier WeAreCodeX, in association with AntiUniversity.org. As a socially/economically engaged arts practice, Work Hard / Play Hard challenged employees/players to get playful, or go to work. 'The game changes you, you never change the game'. Employee PLAYER A 'The faster the better.' Employer PLAYER B

One-pot synthesis of hydroxyapatite–silica nanopowder composite ...

Indian Academy of Sciences (India)

(GIC) and Vickers hardness was evaluated. Results shown that the ... property might lead to extend the clinical indications, especially in stress bearing areas. Keywords. Hydroxyapatite–silica nanopowder; sol–gel technique; glass ionomer cement; hardness. 1. ..... A large hardness means greater resistance to plastic defor-.

Effect of mechanical properties of fillers on the grindability of composite resin adhesives.

Science.gov (United States)

Iijima, Masahiro; Muguruma, Takeshi; Brantley, William A; Yuasa, Toshihiro; Uechi, Jun; Mizoguchi, Itaru

2010-10-01

The purpose of this study was to investigate the effect of filler properties on the grindability of composite resin adhesives. Six composite resin products were selected: Transbond XT (3M Unitek, Monrovia, Calif), Transbond Plus (3M Unitek), Enlight (Ormco, Glendora, Calif), Kurasper F (Kuraray Medical, Tokyo, Japan), Beauty Ortho Bond (Shofu, Kyoto, Japan), and Beauty Ortho Bond Salivatect (Shofu). Compositions and weight fractions of fillers were determined by x-ray fluorescence analysis and ash test, respectively. The polished surface of each resin specimen was examined with a scanning electron microscope. Vickers hardness of plate specimens (15 × 10 × 3 mm) was measured, and nano-indentation was performed on large filler particles (>10 μm). Grindability for a low-speed tungsten-carbide bur was estimated. Data were compared with anlaysis of variance (ANOVA) and the Tukey multiple range test. Relationships among grindability, filler content, filler nano-indentation hardness (nano-hardness), filler elastic modulus, and Vickers hardness of the composite resins were investigated with the Pearson correlation coefficient test. Morphology and filler size of these adhesives showed great variations. The products could be divided into 2 groups, based on composition, which affected grindability. Vickers hardness of the adhesives did not correlate (r = 0.140) with filler nano-hardness, which showed a significant negative correlation (r = -0.664) with grindability. Filler nano-hardness greatly influences the grindability of composite resin adhesives. Copyright © 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Impact of X-ray irradiation on PMMA thin films

Energy Technology Data Exchange (ETDEWEB)

Iqbal, Saman, E-mail: saman.khan343@gmail.com [Physics Department, University of Engineering and Technology, Lahore (Pakistan); Rafique, Muhammad Shahid [Physics Department, University of Engineering and Technology, Lahore (Pakistan); Anjum, Safia [Physics Department, Lahore College for Woman University, Lahore (Pakistan); Hayat, Asma [Physics Department, University of Engineering and Technology, Lahore (Pakistan); Iqbal, Nida [Faculty of Biomedical Engineering and Health Science, Universiti Teknologi Malaysia (UTM) (Malaysia)

2012-10-15

Highlights: Black-Right-Pointing-Pointer PMMA thin films were deposited at 300 Degree-Sign C and 500 Degree-Sign C using PLD technique. Black-Right-Pointing-Pointer These films were irradiated with different fluence of laser produced X-rays. Black-Right-Pointing-Pointer Irradiation affects the ordered packing as well as surface morphology of film. Black-Right-Pointing-Pointer Hardness of film decreases up to certain value of X-ray fluence. Black-Right-Pointing-Pointer Absorption in UV-visible range exhibits a non linear behavior. - Abstract: The objective of this project is to explore the effect of X-ray irradiation of thin polymeric films deposited at various substrate temperatures. pulsed laser deposition (PLD) technique is used for the deposition of PMMA thin films on glass substrate at 300 Degree-Sign C and 500 Degree-Sign C. These films have been irradiated with various X-rays fluences ranging from 2.56 to 5.76 mJ cm{sup -2}. Characterization of the films (before and after the irradiation) is done with help of X-ray Diffractrometer, Optical Microscope, Vickers hardness tester and UV-vis spectroscopy techniques. From XRD data, it is revealed that ordered packing has been improved for the films deposited at 300 Degree-Sign C. However after irradiation the films exhibited the amorphous behavior regardless of the X-ray fluence. Film deposited at 500 Degree-Sign C shows amorphous structure before and after irradiation. Hardness and particle size of thin film have also increased with the increasing substrate temperature. However, the irradiation has reverse effect i.e. the particle size as well as the hardness has reduced. Irradiation has also enhanced the absorption in the UV-visible region.

Dissimilar metal study on C44300 tube to AA7075 -T651 tube plate with and without thread by FWTPET process

Energy Technology Data Exchange (ETDEWEB)

Radhakrishnan, E.; Kumaraswamidhas, L. A. [Indian Institute of Technology (ISM), Jharkhand (India); Muruganandam, D. [Sri Sairam Engineering College, Tamil Nadu (India); Kumaran, S. Senthil [RVS School of Engineering and Technology, Tamilnadu, (India)

2017-05-15

Friction welding has vital industrial role in fabricating automobiles, aerospace, ship building, heat exchangers using similar, dissimilar and bi-metal of ferrous and non-ferrous metals at mass production level. In this study, admiralty brass C44300 tube and aluminium alloy AA7075 -T651, 6 mm thick tube plate were identified as base metals. Different joint surface area profile of with and without thread of different pitch values was chosen to study the mechanical properties and micro structures of these two base metals. 0.1 mm clearance was maintained between the AA7075-T651 tube plate and C44300 tube outer diameter to make friction welding. Taguchi’s L16 orthogonal array techniques were adopted for identifying the most significant ranking process parameters. Analysis of variance (ANOVA) has been used to analyze the input parameter contribution in terms of percentage. Genetic algorithm (GA) was used to access the suitable input parameter value to obtain effective joint strength in terms of hardness, compressive strength and microstructure formation in the interface of the joint. A Compression test (CT) was conducted to evaluate the level of compressive strength of the joint. Threaded profile pair with higher pitch value proved high compressive strength over unthreaded pair. Micro structure for base metal C44300 tube and AA7075-T651 tube plate, Heat affected zone (HAZ) and Weld zone (WZ) of the joint has been studied. Hardness of base metals, HAZ and WZ was measured by micro Vickers hardness tester and the observation shows that hardness at joint interface has been found to be higher in all pairs.

Effect of processing on fracture toughness of silicon carbide as determined by Vickers indentations

Science.gov (United States)

Dannels, Christine M.; Dutta, Sunil

1989-01-01

Several alpha-SiC materials were processed by hot isostatic pressing (HIPing) and by sintering an alpha-SiC powder containing boron and carbon. Several beta-SiC materials were processed by HIPing a beta-SiC powder with boron and carbon additions. The fracture toughnesses K(sub 1c) of these beta- and alpha-SiC materials were estimated from measurements of Vickers indentations. The three formulas used to estimate K(sub 1c) from the indentation fracture patterns resulted in three ranges of K(sub 1c) estimates. Furthermore, each formula measured the effects of processing differently. All three estimates indicated that fine-grained HIPed alpha-SiC has a higher K(sub 1c) than coarsed-grained sintered alpha-SiC. Hot isostatically pressed beta-SiC, which had an ultrafine grain structure, exhibited a K(sub 1c) comparable to that of HIPed alpha-SiC.

First-principle calculations on the structural and electronic properties of hard C{sub 11}N{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Li, Dongxu, E-mail: lidongxu@hqu.edu.cn [College of Materials Science and Engineering, Huaqiao University, Xiamen 361021 (China); Shi, Jiancheng; Lai, Mengling; Li, Rongkai [College of Materials Science and Engineering, Huaqiao University, Xiamen 361021 (China); Yu, Dongli [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

2014-09-15

A graphite-like C{sub 11}N{sub 4} model was built by stacking graphene and a C{sub 3}N{sub 4} triazine layer and simulated by first principle calculations, which transfers to a diamond-like structure under high pressure. The structural, mechanical, and electronic properties of both materials were calculated. The elastic constants of both materials satisfy the Born-criterion. Furthermore, no imaginary frequencies were observed in phonon calculations. The diamond-like C{sub 11}N{sub 4} is semiconducting and consists of polyhedral and hollow C–N cages. The Vickers hardness of diamond-like C{sub 11}N{sub 4} was calculated to be 58 GPa. The phase transformation from graphite-like to diamond-like C{sub 11}N{sub 4} is proposed to occur at approximately 27.2 GPa based on the pressure-dependent enthalpy.

The remineralization potential of cocoa (Theobroma cacao bean extract to increase the enamel micro hardness

Directory of Open Access Journals (Sweden)

Sulistianingsih Sulistianingsih

2017-08-01

Full Text Available Introduction: Remineralization is the process of returning mineral ions into a hydroxyapatite structure characterized by mineral deposition on the enamel surface. The presence of mineral deposition would affect the micro hardness of tooth enamel. The use of fluorine as remineralization agent with side effects such as fluorosis. Cocoa bean extract contains theobromin that can be used as an alternative remineralization ingredients. The objectives was to determine micro hardness email after remineralization using cocoa bean extract as natural material and to compare with fluorine use as synthetic material. Methods: Thirty-six maxillary first premolar tooth crown was cut and planted in the epoxy resin. Teeth were then immersed in demineralization solution at pH 4 for 6 hours. The sample were divided into 2 groups, 18 for the fluorine group and the remaining group of cocoa extract. Vickers microhardness test was used before treatment, after demineralized and after remineralization. Results: Enamel microhardness value before treatment in the fluorine group average value was 376.17 VHN and the cocoa extract group was 357.33 VHN. After demineralization in fluorine group was 268,13 VHN and cocoa extract group was 235,93 VHN. After remineralization in fluorine group was 321,08 VHN and cocoa extract group was 293,86 VHN. The results of the analysis showed that the level of micro hardness email after remineralization was not significantly different in two groups (p > 0.05. Conclusions: Cocoa extract is able to increase the microhardness of enamel so it can act as a substitution for fluorine remineralization.

Hardness and microstructural characterization of API 5L X70 steel pipes welded by HF/ERW process; Caracterizacao microestrutural e de dureza em tubos de aco API 5L X70 soldados pelo processo HF/ERW

Energy Technology Data Exchange (ETDEWEB)

Calcada, Mauricio Vieira; Voorwald, Herman Jacobus Cornelis; Nascimento, Marcelino Pereira do [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia

2010-07-01

The materials that stand in the manufacture of steel pipes are called API, that should have, high mechanical resistance, high corrosion resistance, high fatigue resistance, good weldability, and other properties. Thus, the purpose of this project was to evaluate the microstructure and hardness of welded joints by the HF/ERW process of API 5L X70 steel pipes. The microstructural analysis was performed using a surface finish with grit sizes from 220 to 25 {mu}m e polishing with diamond paste from 9 {mu}m to 0.05 {mu}m; the revelation was made with 3% Nital attack. The Vickers hardness was performed across the welded joint by 33 points to indentation. The results were: 80.5 {+-} 3.4% of ferrite and 19.5 {+-} 3.4% of perlite for microanalysis. As for hardness, the values were: 215.69 HV10 for weld line, 218.65 HV10 for ZTA and 218.95 HV10 for base metal. (author)

Enhancement of the Wear Resistance and Microhardness of Aluminum Alloy by Nd:YaG Laser Treatment

Directory of Open Access Journals (Sweden)

Haitham T. Hussein

2014-01-01

Full Text Available Influence of laser treatment on mechanical properties, wear resistance, and Vickers hardness of aluminum alloy was studied. The specimens were treated by using Nd:YaG laser of energy 780 mj, wavelength 512 nm, and duration time 8 ns. The wear behavior of the specimens was studied for all specimens before and after treatment by Nd:YaG laser and the dry wear experiments were carried out by sing pinon-disc technique. The specimens were machined as a disk with diameter of 25 mm and circular groove in depth of 3 mm. All specimens were conducted by scanning electron microscopy (SEM, energy-dispersive X-ray florescence analysis (EDS, optical microscopy, and Vickers hardness. The results showed that the dry wear rate was decreased after laser hardening and increased Vickers hardness values by ratio of 2.4 : 1. The results showed that the values of wear rate for samples having circular grooves are less than samples without grooves after laser treatment.

Sintering Behavior of Spark Plasma Sintered SiC with Si-SiC Composite Nanoparticles Prepared by Thermal DC Plasma Process

Science.gov (United States)

Yu, Yeon-Tae; Naik, Gautam Kumar; Lim, Young-Bin; Yoon, Jeong-Mo

2017-11-01

The Si-coated SiC (Si-SiC) composite nanoparticle was prepared by non-transferred arc thermal plasma processing of solid-state synthesized SiC powder and was used as a sintering additive for SiC ceramic formation. Sintered SiC pellet was prepared by spark plasma sintering (SPS) process, and the effect of nano-sized Si-SiC composite particles on the sintering behavior of micron-sized SiC powder was investigated. The mixing ratio of Si-SiC composite nanoparticle to micron-sized SiC was optimized to 10 wt%. Vicker's hardness and relative density was increased with increasing sintering temperature and holding time. The relative density and Vicker's hardness was further increased by reaction bonding using additional activated carbon to the mixture of micron-sized SiC and nano-sized Si-SiC. The maximum relative density (97.1%) and Vicker's hardness (31.4 GPa) were recorded at 1800 °C sintering temperature for 1 min holding time, when 0.2 wt% additional activated carbon was added to the mixture of SiC/Si-SiC.

Effect of Ar ion on the surface properties of low density polyethylene

Science.gov (United States)

Zaki, M. F.

2016-04-01

In this paper, low-density polyethylene (LDPE) was irradiated by argon ion with different fluences up to 1015ions/cm2. The optical, chemical and hardness properties have been investigated using UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and micro-indentation tester, respectively. The results showed the ion beam bombardment induced decreases in the transmittance of the irradiated polymer samples. This change in transmittance can be attributed to the formation of conjugated bonds i.e. possible formation of defects and/or carbon clusters. The indirect optical band gap decreased from 3.0 eV for the pristine sample to 2.3 eV for that sample irradiated with the highest fluence of the Ar ion beam. Furthermore, the number of carbon atoms and clusters increased with increasing Ar ion fluences. FTIR spectra showed the formation of new bands of the bombarded polymer samples. Furthermore, polar groups were created on the surface of the irradiated samples which refer to the increase of the hydrophilic nature of the surface of the irradiated samples. The Vicker's hardness increased from 4.9 MPa for the pristine sample to 17.9 MPa for those bombarded at the highest fluence. This increase is attributed to the increase in the crosslinking and alterations of the bombarded surface into hydrogenated amorphous carbon, which improves the hardness of the irradiated samples. The bombarded LDPE surfaces may be used in special applications to the field of the micro-electronic devices and shock absorbers.

Effect of different types of disinfection solution and aging on the hardness and colour stability of maxillofacial silicone elastomers.

Science.gov (United States)

Cevik, Pinar; Yildirim-Bicer, Arzu Z

2017-11-09

Understanding the effect of aging and different disinfecting agents on the physical properties of pigmented maxillofacial silicones may help eliminate the current uncertainty as to the best follow-up suggestions for the patients treated with silicone prostheses. One hundred fifty specimens (14 × 2 mm) were evaluated for colour and 75 specimens (30 × 10 mm) for hardness (total, 225 specimens). Five specimens were used for hardness testing in each disinfecting solution while 10 silicone specimens were used for colour evaluation. The samples were separated into 5 groups and the initial hardness and colour evaluations were performed and placed in disinfectant solution (neutral soap, effervescent tablet, 0.2% chlorhexidine, 4% chlorhexidine, sodium hypochlorite). A second set of colour and hardness measurements was taken after 48 hours of disinfection and 1,008 hours of artificial aging in a QUV-accelerated weathering tester. Two-way and 1-way analysis of variance with Tukey tests and paired t-test were used for statistical analysis (α = 0.05). Before artificial aging, the hardness value of the red pigment group was found to be significantly lower than that of the brown pigment group. After aging, the lowest Shore A value was seen in the neutral soap group, while the highest was seen in the effervescent tablet. Based on the results of this study, chlorohexidine 0.2% was found to be most suitable agent for disinfection of the prostheses. Washing with neutral soap caused loss of pigment from the surface of the silicones. Sodium hypochlorite was found to have a colour-fading effect on silicone specimens.

Effect of Ti content on structure and properties of Al2CrFeNiCoCuTix high-entropy alloy coatings

International Nuclear Information System (INIS)

Qiu, X.W.; Zhang, Y.P.; Liu, C.G.

2014-01-01

Highlights: • Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. • Al 2 CrFeNiCoCuTi x coatings show excellent corrosion resistance and wear resistance. • Al 2 CrFeNiCoCuTi x coatings play a good protective effect on Q235 steel. • Ti element promotes the formation of a BCC structure in a certain extent. -- Abstract: The Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. The structure, hardness, corrosion resistance, wear resistance and magnetic property were studied by metallurgical microscope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation tribometer and multi-physical tester. The result shows that, Al 2 CrFeNiCoCuTi x high-entropy alloy samples consist of the cladding zone, bounding zone, heat affected zone and substrate zone. The bonding between the cladding layer and the substrate of a good combination; the cladding zone is composed mainly of equiaxed grains and columnar crystal; the phase structure of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings simple for FCC, BCC and Laves phase due to high-entropy affect. Ti element promotes the formation of a BCC structure in a certain extent. Compared with Q235 steel, the free-corrosion current density of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings is reduced by 1–2 orders of magnitude, the free-corrosion potential is more “positive”. With the increasing of Ti content, the corrosion resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings enhanced in 0.5 mol/L HNO 3 solution. Compared with Q235 steel, the relative wear resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings has improved greatly; both the hardness and plasticity are affecting wear resistance. Magnetization loop shows that, Ti 0.0 high-entropy alloy is a kind of soft magnetic materials

Hard electronics; Hard electronics

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

Interference of apex locator, pulp tester and diathermy on pacemaker function.

Science.gov (United States)

Sriman, Narayanan; Prabhakar, V; Bhuvaneswaran, J S; Subha, N

2015-01-01

The purpose of this study was to evaluate the effects of three electronic apex locators (EAL), electric pulp tester (EPT) and diathermy on pacemaker function in vitro. Three EALs: Root ZX (J. Morita Co., Tustin, CA, U.S.A.), Propex (Dentsply), Mini Apex locator (SybronEndo, Anaheim, CA, USA), EPT (Parkell pulp vitality tester Farmingdale, NY, USA) and Diathermy (Neomed 250 B) were tested for any interference with one pacemaker (A medtronic kappa KVDD901-serial number: PLE734632S). Directly connecting the pacemaker lead with the EAL/EPT/diathermy operating on a flat bench top, the telemetry wand was held directly over the pacemaker to monitor the pacing pattern for a period of 30 s. Pacemaker activity was continuously recorded on the telemetric programmer and electro gram (EGM) readings examined for pacer inhibition, noise reversion or inappropriate pacemaker pulses. All the three apex locators showed no pacing interference or background noise during its function or at rest. The EGM readings of EPT showed varying levels of background noise in between pacing however, this did not affect the normal pacing pattern and the pacing interval remained constant. EGM readings of diathermy showed an increase in the pacing interval (irregular pacing pattern) followed by complete inhibition of the pacing system. The tested EALs do not interfere with cardiac pacemaker function. The tested EPT showed varying levels of background noise but does not interfere with cardiac pacemaker function. Use of Diathermy interfered with the normal pacing, leading to complete inhibition of the pacing system.

CORROSION IN ACIDIC BEVERAGES AND RECOVERY OF MICROHARDNESS OF HUMAN TEETH ENAMEL

Directory of Open Access Journals (Sweden)

Petra Gaalova

2016-05-01

Full Text Available We studied the influence of corrosion in acidic beverages (white wine, pH~3.5 on micromechanical properties of human teeth. Simultaneously, the effect of fluorine-containing mouthwash (pH~4.4 and of artificial saliva (pH~5.3 in terms of their protective action against corrosion, and the recovery of mechanical properties through fluoridation and re-calcification was studied. The influence of the solutions on Vickers hardness of dental enamel was monitored on the basis of results from the corrosion tests carried out under quasi-dynamic conditions. The tests were performed at the temperature corresponding to the temperature of human body (37°C. The measurements confirmed a significant deterioration of microhardness with prolonged exposure to white wine. The Vickers hardness decreased from 347 HV0.2 in un-corroded specimens to 186 HV0.2 in samples corroded for 60 minutes in white wine. A recovery of Vickers hardness was observed after 60 minutes exposition time in the fluoridation solution, with the increase from 186 to 372 HV0.2. Similar effect was observed in the artificial saliva solution, with observed hardness increase from 186 to 320 HV0.2. Healing of corrosion-induced defects by the action of both solutions was observed by SEM, and associated with observed increase of hardness

The effect of heat treatments applied to superstructure porcelain on the mechanical properties and microstructure of lithium disilicate glass ceramics.

Science.gov (United States)

Özdemir, Hatice; Özdoğan, Alper

2018-01-30

The aim of this study was to investigate that heat treatments with different numbers applied to superstructure porcelain whether effects microstructure and mechanical properties of lithium disilicate ceramic (LDC). Eighty disc-shaped specimens were fabricated from IPS e.max Press. Specimens were fired at heating values of porcelain in different numbers and divided four groups (n=5). Initial Vickers hardness were measured and X-ray diffraction (XRD) analysis was performed. Different surface treatment were applied and then Vickers hardness, surface roughness and environmental scanning electron microscopy (ESEM) analysis were performed. Data were analyzed with Varyans analysis and Tukey HSD test (α=0.05). Initial hardness among groups was no significant different (p>0.05), but hardness and surface roughness after surface treatments were significant different (pmicrostructure of LDC. Increasing firing numbers and surface treatments effect the microstructure of LDC.

Pengembangan Indentation Size Effect (ISE Dalam Penentuan Koefisien Pengerasan Regang Baja

Directory of Open Access Journals (Sweden)

I Nyoman Budiarsa

2016-07-01

Full Text Available Abstrak: Hubungan antara sifat material konstitutif dengan indentasi kekerasan (Hardness Indentation termasuk ISE (Indentation Size Effect telah dikembangkan dan dievaluasi dengan indentasi Vickers, hal Ini akan menjadi alat yang berguna dalam mengevaluasi kelayakan penggunaan nilai kekerasan dalam memprediksi parameter bahan konstitutif dengan mengacu pada syarat akurasi pada rentang semua potensi bahan. ISE dapat konsisten diukur dan dapat berpotensi dihubungkan dengan H/E rasio. Skala ISE dari sampel yang diuji menunjukkan pengulangan yang konsisten dan berhubungan kuat dengan sifat material secara signifikan. Hal Ini berpotensi memberikan set data eksperimen yang mencerminkan sifat material yang terkait dengan ketegangan gradien dan kerapatan dislokasi selama proses indentasi Konsep untuk menggunakan data ukuran indentasi Vickers telah dikembangkan untuk meningkatkan akurasi sifat invers pemodelan berdasarkan kekerasan menggunakan baja sebagai sistem bahan. Penelitian ini menunjukkan bahwa ada ISE signifikan dalam tes kekerasan Vickers dimana skala dan reliabilitas ISE dianalisis dengan fitting data mengikuti Power law and proportional resistance model Sebuah konsep baru menggunakan data ISE untuk memperkirakan Koefisien Pengerasan Regang (n nilai-nilai dari baja telah dievaluasi dan menunjukkan hasil yang baik untuk mempersempit kisaran sifat material yang diprediksi berdasarkan nilai-nilai kekerasan. . Kata kunci: ISE, H/E rasio, Koefisien Pengerasan Regang (n Abstract: The relationship between the constitutive material properties with Hardness indentation including ISE (indentation Size Effect has been developed and evaluated by Vickers indentation. This provided a useful tool in evaluating the feasibility of using of hardness value in predicting the constitutive material parameters with reference to the terms of accuracy in the all the potential materials range. ISE can be consistently measured and may potentially be associated with H

Mechanical properties of Al-Cu alloy-SiC composites

Science.gov (United States)

Anggara, B. S.; Handoko, E.; Soegijono, B.

2014-09-01

The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to get better quality of back to back hardness Vickers of Al-Cu alloys.

Mechanical properties of Al-Cu alloy-SiC composites

Energy Technology Data Exchange (ETDEWEB)

Anggara, B. S., E-mail: anggorobs1960@yahoo.com [Jurusan Fisika, FMIPA Universitas Negeri Jakarta, Indonesia 13220 and PPS Ilmu Material, Department Fisika, FMIPA, Universitas Indonesia (Indonesia); Handoko, E. [Jurusan Fisika, FMIPA Universitas Negeri Jakarta, 13220 (Indonesia); Soegijono, B. [PPS Ilmu Material, Department Fisika, FMIPA, Universitas Indonesia (Indonesia)

2014-09-25

The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to get better quality of back to back hardness Vickers of Al-Cu alloys.

Effect of cobalt on microstructure and properties of AlCr1.5CuFeNi2Cox high-entropy alloys

Science.gov (United States)

Kukshal, Vikas; Patnaik, Amar; Bhat, I. K.

2018-04-01

The present paper investigates the effect of Co addition on the alloying behaviour, microstructure and the resulting properties of cast AlCr1.5CuFeNi2Cox high-entropy alloys intended to be used for high temperature applications. The elements Al, Cr, Cu, Fe, Ni and Co (Purity > 99) weighing approximately 800 g was melted in a high temperature vacuum induction furnace. The microstructure, phase transformation, density, microhardness and compressive strength of the samples were analysed using x-ray diffraction (XRD), scanning electron microscopes (SEM), Vickers microhardness tester and universal Testing machine. The crystalline structure of the alloys exhibits simple FCC and BCC phases. The microstructures investigation of the alloys shows the segregation of copper in the interdendritic region resulting in Cu-rich FCC phase. The addition of Co further enhances the formation of FCC phase resulting in the decrease in micro hardness value of the alloys, which varies from 471 HV to 364 HV with increase in the cobalt content from x = 0 to x = 1 (molar ratio). The similar decreasing trend is also observed for the compressive strength of the alloys.

Comparative Studies on microstructure, mechanical and corrosion behaviour of DMR 249A Steel and its welds

Science.gov (United States)

Mohammed, Raffi; Dilkush; Madhusudhan Reddy, G.; Srinivasa Rao, K.

2018-03-01

DMR249A Medium strength (low carbon) Low-alloy steels are used as structural components in naval applications due to its low cost and high availability. An attempt has been made to weld the DMR 249A steel plates of 8mm thickness using shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW). Welds were characterized for metallography to carry out the microstructural changes, mechanical properties were evaluated using vickers hardness tester and universal testing machine. Potentio-dynamic polarization tests were carried out to determine the pitting corrosion behaviour. Constant load type Stress corrosion cracking (SCC) testing was done to observe the cracking tendency of the joints in a 3.5%NaCl solution. Results of the present study established that SMA welds resulted in formation of relatively higher amount of martensite in ferrite matrix when compared to gas tungsten arc welding (GTAW). It is attributed to faster cooling rates achieved due to high thermal efficiency. Improved mechanical properties were observed for the SMA welds and are due to higher amount of martensite. Pitting corrosion and stress corrosion cracking resistance of SMA welds were poor when compared to GTA welds.

Surface improvement and biocompatibility of TiAl{sub 24}Nb{sub 10} intermetallic alloy using rf plasma nitriding

Energy Technology Data Exchange (ETDEWEB)

Abd El-Rahman, A.M. [Physics Department, Faculty of Science, Sohag University (Egypt)], E-mail: ahmedphys96@hotmail.com; Maitz, M.F. [Institut fuer Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden Rossendorf (Germany); Kassem, M.A. [Department of Materials and Metals Engineering, Faculty of Petroleum and Mining Engineering, Suez Canal University (Egypt); El-Hossary, F.M. [Physics Department, Faculty of Science, Sohag University (Egypt); Prokert, F.; Reuther, H.; Pham, M.T.; Richter, E. [Institut fuer Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden Rossendorf (Germany)

2007-09-30

The present work describes the surface improvement and biocompatibility of TiAl{sub 24}Nb{sub 10} intermetallic alloy using rf plasma nitriding. The nitriding process was carried out at different plasma power from 400 W to 650 W where the other plasma conditions were fixed. Grazing incidence X-ray diffractometry (GIXRD), Auger electron spectroscopy (AES), tribometer and a nanohardness tester were employed to characterize the nitrided layer. Further potentiodynamic polarization method was used to describe the corrosion behavior of the un-nitrided and nitrided alloy. It has been found that the Vickers hardness (HV) and corrosion resistance values of the nitrided layers increase with increasing plasma power while the wear rates of the nitrided layers reduce by two orders of magnitude as compared to those of the un-nitrided layer. This improvement in surface properties of the intermetallic alloy is due to formation of a thin modified layer which is composed of titanium nitride in the alloy surface. Moreover, all modified layers were tested for their sustainability as a biocompatible material. Concerning the application area of biocompatibility, the present treated alloy show good surface properties especially for the nitrided alloy at low plasma power of 400 W.

Microstructure and mechanical property change of dissimilar metal welds Alloy 600 - Alloy 182 - A508 Gr. 3 according to thermal aging effect at 400 .deg. C

Energy Technology Data Exchange (ETDEWEB)

Ham, Jun Hyuk; Choi, Kyoung Joon; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2015-10-15

To prevent such critical matters above mentioned, investigation about degradation mechanism of materials by thermal aging should be conducted. However, there are no sufficient studies on this field. Therefore, the final goal of this study is to investigate microstructure along the DMW undergone thermal aging process. Firstly, in order to get a reference data for further comparison analysis which is expected to show degradation mechanism of the weld joint, un-heated weld joint was investigated with several instruments, Vickers hardness tester, scanning electron microscope (SEM), and an energy-dispersive X-ray spectrometer (EDS). Detail instrumental analysis in Alloy 600 - Alloy 182 - A508 Gr. 3 DMW joint were performed in order to investigate microstructure and mechanical properties of material. Following conclusions can be drawn from this study. Alloy 182 has austenitic dendrite structure which is formed by heat flow during welding process. Type-II boundaries were observed at the interface between Alloy 182 and A508 Gr. 3. Chemical composition shows rapid transition at the interface which makes 3000 µm of chromium dilution zone. Microstructure of A508 Gr. 3 was investigated from the interface between Alloy 182 to base metal.

Microprocessor tester for the treat upgrade reactor trip system

International Nuclear Information System (INIS)

Lenkszus, F.R.; Bucher, R.G.

1984-01-01

The upgrading of the Transient Reactor Test (TREAT) Facility at ANL-Idaho has been designed to provide additional experimental capabilities for the study of core disruptive accident (CDA) phenomena. In addition, a programmable Automated Reactor Control System (ARCS) will permit high-power transients up to 11,000 MW having a controlled reactor period of from 15 to 0.1 sec. These modifications to the core neutronics will improve simulation of LMFBR accident conditions. Finally, a sophisticated, multiply-redundant safety system, the Reactor Trip System (RTS), will provide safe operation for both steady state and transient production operating modes. To insure that this complex safety system is functioning properly, a Dedicated Microprocessor Tester (DMT) has been implemented to perform a thorough checkout of the RTS prior to all TREAT operations

Prophage induction, mutagenesis, and cell survival of Ames' mutagen tester strains after 8-methoxypsoralen plus ultraviolet light-A

Energy Technology Data Exchange (ETDEWEB)

Wheeler, L.A.; DeMeo, M. (California Univ., Los Angeles (USA)); Lowe, N. (Combined UCLA-WADSWORTH Dermatology Program, Los Angeles, CA (USA))

1983-10-01

8-methoxypsoralen (8-MOP) is not detected as a mutagen in the standard Ames test either in the presence or absence of S9-mix and/or ultraviolet light-A (320-400 nm). The Ames strains have been shown to harbor bacteriophages that are inducible by carcinogens and mutagens. Psoralen plus UVA (PUVA) was found to be a potent prophage inducing treatment. Induction was observed in TA1535, TA1538, TA98, TA100, TA1978 and TA1975 with 8-MOP and UVA. PUVA is a potent bactericidal treatment at concentrations of 8-MOP above 0.5 ..mu..g/ml and 2.5 kJ/m/sup 2/ in tester strains TA1535, TA1538, TA98 and TA100. PUVA is known to be bactericidal, but the cytotoxicity observed in the present study was unique in that the frameshift tester strains (TA1538 and TA98) were more sensitive to the lethal effects of PUVA than the base pair tester strains (TA1535 and TA100). The differential cytotoxicity in such closely related strains led to the examination of some of the strains from which the Ames strains were derived. It is postulated that TA1535 retains a DNA repair function that is lost by TA1538 during the selection for uvrB deficient strains.

Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

Directory of Open Access Journals (Sweden)

Ugur Erdemir

2013-04-01

Full Text Available Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group. For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05. Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001 in different solutions (p<0.001. The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001. The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

A portable fracture toughness tester for biological materials

Science.gov (United States)

Darvell, B. W.; Lee, P. K. D.; Yuen, T. D. B.; Lucas, P. W.

1996-06-01

A portable mechanical tester is described which is both lightweight and cheap to produce. The machine is simple and convenient to operate and requires only a minimum of personnel training. It can be used to measure the fundamental mechanical properties of pliant solids, particularly toughness (in the sense of `work of fracture') using either scissors or wedge tests. This is achieved through a novel hardware integration technique. The circuits are described. The use of the machine does not require a chart recorder but it can be linked to a personal computer, either to show force - displacement relationships or for data storage. The design allows the use of any relatively `soft' mechanical test, i.e. tests in which the deformability of the frame of the machine and its load cell do not introduce significant errors into the results. Examples of its use in measuring the toughness of biomaterials by scissors (paper, wood) and wedges (mung bean starch gels) are given.

Effects of various light curing methods on the leachability of uncured substances and hardness of a composite resin.

Science.gov (United States)

Moon, H-J; Lee, Y-K; Lim, B-S; Kim, C-W

2004-03-01

The purpose of this study was to evaluate the effect of the various light curing units (plasma arc, halogen and light-emitting diodes) and irradiation methods (one-step, two-step and pulse) using different light energy densities on the leachability of unreacted monomers (Bis-GMA and UDMA) and the surface hardness of a composite resin (Z250, 3M). Leachability of the specimens immersed for 7 days in ethanol was analysed by HPLC. Vicker's hardness number (VHN) was measured immediately after curing (IC) and after immersion in ethanol for 7 days. Various irradiation methods with three curing units resulted in differences in the amount of leached monomers and VHN of IC when light energy density was lower than 17.0 J cm(-2) (P = 0.05). However, regardless of curing units and irradiation methods, these results were not different when the time or light energy density increased. When similar light energy density was irradiated (15.6-17.7 J cm(-2)), the efficiency of irradiation methods was different by the following order: one-step > or = two-step > pulse. These results suggest that the amount of leached monomers and VHN were influenced by forming polymer structure in activation and initiation stages of polymerization process with different light source energies and curing times.

Sintering Behavior of Spark Plasma Sintered SiC with Si-SiC Composite Nanoparticles Prepared by Thermal DC Plasma Process.

Science.gov (United States)

Yu, Yeon-Tae; Naik, Gautam Kumar; Lim, Young-Bin; Yoon, Jeong-Mo

2017-11-25

The Si-coated SiC (Si-SiC) composite nanoparticle was prepared by non-transferred arc thermal plasma processing of solid-state synthesized SiC powder and was used as a sintering additive for SiC ceramic formation. Sintered SiC pellet was prepared by spark plasma sintering (SPS) process, and the effect of nano-sized Si-SiC composite particles on the sintering behavior of micron-sized SiC powder was investigated. The mixing ratio of Si-SiC composite nanoparticle to micron-sized SiC was optimized to 10 wt%. Vicker's hardness and relative density was increased with increasing sintering temperature and holding time. The relative density and Vicker's hardness was further increased by reaction bonding using additional activated carbon to the mixture of micron-sized SiC and nano-sized Si-SiC. The maximum relative density (97.1%) and Vicker's hardness (31.4 GPa) were recorded at 1800 °C sintering temperature for 1 min holding time, when 0.2 wt% additional activated carbon was added to the mixture of SiC/Si-SiC.

Pulse electrodeposition of self-lubricating Ni–W/PTFE nanocomposite coatings on mild steel surface

Energy Technology Data Exchange (ETDEWEB)

Sangeetha, S. [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Kalaignan, G. Paruthimal, E-mail: pkalaignan@yahoo.com [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Anthuvan, J. Tennis [M. Kumarasamy College of Engineering, Karur, Tamil Nadu (India)

2015-12-30

Graphical abstract: - Highlights: • PTFE polymer inclusion on Ni–W alloy matrix was electrodeposited by pulse current method. • Tribological properties and electrochemical characterizations of the nanocomposite coatings were analyzed. • The hydrophobic behaviour of Ni–W/PTFE nanocomposite coating was measured. • Ni–W/PTFE nanocomposite coatings have showed superior tribological properties and corrosion resistance relative to that of the Ni–W alloy matrix. - Abstract: Ni–W/PTFE nanocomposite coatings with various contents of PTFE (polytetafluoroethylene) particles were prepared by pulse current (PC) electrodeposition from the Ni–W plating bath containing self lubricant PTFE particles to be co-deposited. Co-deposited PTFE particulates were uniformly distributed in the Ni–W alloy matrix. The coatings were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), X-ray Diffractometry (XRD) and Vicker's micro hardness tester. Tafel Polarization and electrochemical Impedance methods were used to evaluate the corrosion resistance behaviour of the nanocomposite coatings in 3.5% NaCl solution. It was found that, the Ni–W/PTFE nanocomposite coating has better corrosion resistance than the Ni–W alloy coating. Surface roughness and friction coefficient of the coated samples were assessed by Mitutoyo Surftest SJ-310 (ISO1997) and Scratch tester TR-101-M4 respectively. The contact angle (CA) of a water droplet on the surface of nanocomposite coating was measured by Optical Contact Goniometry (OCA 35). These results indicated that, the addition of PTFE in the Ni–W alloy matrix has resulted moderate microhardness, smooth surface, less friction coefficient, excellent water repellency and enhanced corrosion resistance of the nanocomposite coatings.

Kekerasan mikro enamel gigi permanen muda setelah aplikasi bahan pemutih gigi dan pasta remineralisasi (Enamel micro hardness of young permanent tooth after bleaching and remineralization paste application

Directory of Open Access Journals (Sweden)

Budianto Liwang

2014-12-01

Full Text Available Background: Studies showed that bleaching agent had demineralization effect to enamel, and encourage use of remineralization paste after bleaching treatment especially in young permanent tooth which in post-eruptive enamel maturation. Purpose: The study ere aimed to determine the bleaching agent effect on enamel surface micro hardness, and to determine the effect of remineralization paste application on enamel surface micro hardness of young permanent tooth after bleaching treatment. Methods: Fourteen young permanent teeth were placed in a block of resin with a window on the buccal surface enamel. The initial enamel surface hardness was measured using Microvickers Hardness Tester. Then the application of hydrogen peroxide bleaching materials 30% was done three times for 15 minutes and followed by surface hardness of enamel measurement. Samples were divided into 2 groups; the first group was applied paste of Hydroxy apatite + NaF 1450ppm , and the second group was applied paste of CPP–ACP + NaF 900ppm. Each paste was applied for 30 minutes for 7 days, then the enamel surface hardness of samples were measured. Results: The enamel surface micro hardness decreased after bleaching from 333.09 ± 10.49 VHN to 299.15±5.70 VHN. Micro hardness after application of Hidroxy apatite + NaF 1450ppm was 316.61±5.87 VHN and after application of CPP-ACP + NaF 900ppm was 319.94±3.25 VHN, however the micro hardness still lower than initial micro hardness. Conclusion: Tooth bleaching agent caused a decrease of enamel surface micro hardness in young permanent tooth. The use of remineralization paste enabled to increase the enamel surface micro hardness young permanent tooth.Latar belakang: Penelitian-penelitian sebelumnya menunjukkan bahwa produk pemutih gigi memiliki efek demineralisasi enamel gigi, dan mendorong penggunaan pasta remineralisasi setelah pemutihan gigi terutama di gigi muda permanen yang enamelnya masih dalam proses maturasi pasca-erupsi. Tujuan

Effect of the Ultrasonic Nanocrystalline Surface Modification (UNSM on Bulk and 3D-Printed AISI H13 Tool Steels

Directory of Open Access Journals (Sweden)

In-Sik Cho

2017-11-01

Full Text Available A comparative study of the microstructure, hardness, and tribological properties of two different AISI H13 tool steels—classified as the bulk with no heat treatment steel or the 3D-printed steel—was undertaken. Both samples were subjected to ultrasonic nanocrystalline surface modification (UNSM to further enhance their mechanical properties and improve their tribological behavior. The objective of this study was to compare the mechanical properties and tribological behavior of these tool steels since steel can exhibit a wide variety of mechanical properties depending on different manufacturing processes. The surface hardness of the samples was measured using a micro-Vickers hardness tester. The hardness of the 3D-printed AISI H13 tool steel was found to be much higher than that of the bulk one. The surface morphology of the samples was characterized by electron backscattered diffraction (EBSD in order to analyze the grain size and number of fractions with respect to the misorientation angle. The results revealed that the grain size of the 3D-printed AISI H13 tool steel was less than 0.5 μm, whereas that of the bulk tool steel was greater than 4 μm. The number of fractions of the bulk tool steel was about 0.5 μm at a low misorientation angle, and it decreased gradually with increasing misorientation angle. The low-angle grain boundary (LAGB and high-angle grain boundary (HAGB of the bulk sample were about 21% and 79%, respectively, and those of the 3D-printed sample were about 8% and 92%, respectively. Moreover, the friction and wear behavior of the UNSM-treated AISI H13 tool steel specimen was better than those of the untreated one. This study demonstrated the capability of 3D-printed AISI H13 tool steel to exhibit excellent mechanical and tribological properties for industrial applications.

Thermal Aging Effects on Heat Affected Zone of Alloy 600 in Dissimilar Metal Weld

Energy Technology Data Exchange (ETDEWEB)

Ham, Jun Hyuk; Choi, Kyoung Joon; Yoo, Seung Chang; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

2016-05-15

Dissimilar metal weld (DMW), consists of Alloy 600, Alloy 182, and A508 Gr.3, is now being widely used as the reactor pressure vessel penetration nozzle and the steam generator tubing material for pressurized water reactors (PWR) because of its mechanical property, thermal expansion coefficient, and corrosion resistance. The heat affected zone (HAZ) on Alloy 600 which is formed by welding process is critical to crack. According to G.A. Young et al. crack growth rates (CGR) in the Alloy 600 HAZ were about 30 times faster than those in the Alloy 600 base metal tested under the same conditions [3]. And according to Z.P. Lu et al. CGR in the Alloy 600 HAZ can be more than 20 times higher than that in its base metal. To predict the life time of components, there is a model which can calculate the effective degradation years (EDYs) of the material as a function of operating temperature. This study was conducted to investigate how thermal aging affects the hardness of dissimilar metal weld from the fusion boundary to Alloy 600 base metal and the residual strain at Alloy 600 heat affected zone. Following conclusions can be drawn from this study. The hardness, measured by Vickers hardness tester, peaked near the fusion boundary between Alloy 182 and Alloy 600, and it decreases as the picked point goes to Alloy 600 base metal. Even though the formation of precipitate such as Cr carbide, thermal aging doesn't affect the value and the tendency of hardness because of reduced residual stress. According to kernel average misorientation mapping, residual strain decreases when the material thermally aged. And finally, in 30 years simulated specimen, the high residual strain almost disappears. Therefore, the influence of residual strain on primary water stress corrosion cracking can be diminished when the material undergoes thermal aging.

Two feasible approaches to enhance the wear behaviors of NiCrBSi coating in atmosphere and aqueous environments

Science.gov (United States)

Ye, Yuwei; Wang, Chunting; Zheng, Wenru; Xiong, Wei; Wang, Yongxin; Li, Xiaogang

2017-09-01

NiCrBSi coating was deposited successfully on the surface of 316 stainless steel substrate by means of plasma spraying. The microstructures and mechanical property were analyzed by scanning electron microscopy, x-ray diffraction, and a Vickers hardness tester. The wear performances of the coatings sliding against the GCr15 ball under ambient air and water conditions were investigated, and two feasible approaches (tungsten carbide (WC)-doping and heat treatment) were used to improve the tribological performance. Results showed that the hardness of the NiCrBSi coating increased by 12.5% and 28.5% and the porosity decreased by 26.1% and 47.8%, respectively, after WC-doping and heat treatment. During dry friction, the friction coefficient and wear rate of the NiCrBSi coating were about 0.47 and 1.4  ×  10-5 mm3 N-1 m-1, respectively. These values were higher than those obtained on other coatings. In water conditions, all coatings showed a lower friction and wear rate than that in ambient air, which was as a result of the lubrication effect of water. Significantly, with WC-doping and heat treatment, the friction coefficients of both coatings were about 18.5% and 36.7%, respectively, lower than that of the NiCrBSi coating. Furthermore, the wear rates of both coatings were about 20% and 70%, respectively, lower than that of the NiCrBSi coating.

Inter-tester reliability of selected clinical tests for long-lasting temporomandibular disorders.

Science.gov (United States)

Julsvoll, Elisabeth Heggem; Vøllestad, Nina Køpke; Opseth, Gro; Robinson, Hilde Stendal

2017-09-01

Clinical tests used to examine patients with temporomandibular disorders vary in methodological quality, and some are not tested for reliability. The purpose of this cross-sectional study was to evaluate inter-tester reliability of clinical tests and a cluster of tests used to examine patients with long-lasting temporomandibular disorders. Forty patients with pain in the temporomandibular area treated by health-professionals were included. They were between 18-70 years, had 65 symptomatic (33 right/32 left) and 15 asymptomatic joints. Two manual therapists examined all participants with selected tests. Percentage agreement and the kappa coefficient ( k ) with 95% confidence interval (CI) were used to evaluate the tests with categorical outcomes. For tests with continuous outcomes, the relative inter-tester reliability was assessed by the intraclass-correlation-coefficient (ICC 3,1 , 95% CI) and the absolute reliability was calculated by the smallest detectable change (SDC). The best reliability among single tests was found for the dental stick test, the joint-sound test ( k  = 0.80-1.0) and range of mouth-opening (ICC 3,1 (95% CI) = 0.97 (0.95-0.98) and SDC = 4 mm). The reliability of cluster of tests was excellent with both four and five positive tests out of seven. The reliability was good to excellent for the clinical tests and the cluster of tests when performed by experienced therapists. The tests are feasible for use in the clinical setting. They require no advanced equipment and are easy to perform.

Hip- and knee-strength assessments using a hand-held dynamometer with external belt-fixation are inter-tester reliable

DEFF Research Database (Denmark)

Thorborg, Kristian; Bandholm, Thomas; Hölmich, Per

2013-01-01

PURPOSE: In football, ice-hockey, and track and field, injuries have been predicted, and hip- and knee-strength deficits quantified using hand-held dynamometry (HHD). However, systematic bias exists when testers of different sex and strength perform the measurements. Belt-fixation of the dynamome...

Microhardness studies on nonlinear optical L-alanine single crystals

Indian Academy of Sciences (India)

2016-08-26

Aug 26, 2016 ... ... increasing load. Meyer's index number () calculated from v shows that the material belongs to the soft material category. Using Wooster's empirical relation, the elastic stiffness constant (11) was calculated from Vickers hardness values. Young's modulus was calculated using Knoop hardness values.

Effect of Mo-Fe substitution on glass forming ability, thermal stability, and hardness of Fe-C-B-Mo-Cr-W bulk amorphous alloys

Energy Technology Data Exchange (ETDEWEB)

Khalifa, Hesham E.; Cheney, Justin L. [University of California, San Diego Materials Science and Engineering Program, 9500 Gilman Drive, La Jolla, CA 92093-0411 (United States); Vecchio, Kenneth S. [University of California, San Diego Department of NanoEngineering, 9500 Gilman Drive, La Jolla, CA 92093-0411 (United States)], E-mail: kvecchio@ucsd.edu

2008-08-25

Amorphous Fe{sub 67-x}C{sub 10}B{sub 9}Mo{sub 7+x}Cr{sub 4}W{sub 3} (x = 1-7 at.%) plates with 640 {mu}m thickness were prepared by copper mold casting. The thermal properties and microstructural development during heat treatments were investigated by a combination of differential scanning calorimetry (DSC), differential thermal analysis, and X-ray diffractometry (XRD). The glass forming ability (GFA) and activation energy for crystallization have a distinct dependence on Mo content. Fe{sub 62}C{sub 10}B{sub 9}Mo{sub 12}Cr{sub 4}W{sub 3} is the best glass former in this study, demonstrating a supercooled liquid region, {delta}T{sub x} = 51 K, and an activation energy for crystallization, Q = 453 kJ/mol. The GFA of alloys in this system was governed by elastic strain optimization resulting directly from the variation in Mo content. Heat treatments were performed to demonstrate resistance to crystallization under typical processing conditions. Alloys in this system exhibited a three-phase evolution during crystallization. A second set of heat treatments was performed to identify each phase. Hardness data was collected at each of the heat treatment conditions, and a bulk metallic glasses (BMG)-derived composite containing a Mo-rich phase exhibited Vickers Hardness in excess of 2000. The fully amorphous alloys had an average hardness approaching 1500.

Microstructure and hardness studies of Inconel 718 manufactured by selective laser melting before and after solution heat treatment

International Nuclear Information System (INIS)

Tucho, Wakshum M.; Cuvillier, Priscille; Sjolyst-Kverneland, Atle; Hansen, Vidar

2017-01-01

The microstructure of Additive Manufactured (AM) Inconel 718 in general and Selective Laser Melting (SLM), in particular is different from the material produced by conventional methods due to the rapid solidification process associated with the former. As a result, the widely adapted standard solution heat treatment temperature (<1100 °C) for conventional material is found to be not high enough for materials fabricated with SLM method in order to dissolve Laves and other microsegregated phases for releasing the ageing constituents (Nb, Ti, Al) sufficiently into the alloy matrix. In this study, sample of Inconel 718 fabricated with SLM method were solution heat-treated to 1100 °C or 1250 °C at different hold times to investigate the dissolution of macro- and micro-segregated precipitates. Investigations of microstructure and segregation in as-printed and solution heat-treated states have been studied using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Optical Microscopy (OM). Measurement of material hardness was performed with Vickers hardness tests. The microstructure of the as-printed parts exhibit non-columnar grains, but contain well-shaped columnar/cellular sub-grains. The intergranular boundaries are decorated with high density of dislocations and segregated particles. Tremendous stress relief and grain coarsening were observed with solution heat treatment. In particular, at 1250 °C annealing, the sub-grains, including precipitates and dislocation networks along the sub-grain boundaries, were entirely dissolved. However, the 1100/1250 °C solution heat treatment scheme could not dissolve microsegregated precipitates and carbides completely. Details of the analysis on microstructure, dissolution of precipitates and hardness are presented.

Microstructure and hardness studies of Inconel 718 manufactured by selective laser melting before and after solution heat treatment

Energy Technology Data Exchange (ETDEWEB)

Tucho, Wakshum M., E-mail: wakshum.m.tucho@uis.no [Department of Mechanical and Structural Engineering and Materials Science, University of Stavanger, N-4036 Stavanger (Norway); Cuvillier, Priscille [Department of Mechanical and Structural Engineering and Materials Science, University of Stavanger, N-4036 Stavanger (Norway); Sjolyst-Kverneland, Atle [Roxar/Emerson Process Management, POB 112, 4065 Stavanger (Norway); Hansen, Vidar [Department of Mechanical and Structural Engineering and Materials Science, University of Stavanger, N-4036 Stavanger (Norway)

2017-03-24

The microstructure of Additive Manufactured (AM) Inconel 718 in general and Selective Laser Melting (SLM), in particular is different from the material produced by conventional methods due to the rapid solidification process associated with the former. As a result, the widely adapted standard solution heat treatment temperature (<1100 °C) for conventional material is found to be not high enough for materials fabricated with SLM method in order to dissolve Laves and other microsegregated phases for releasing the ageing constituents (Nb, Ti, Al) sufficiently into the alloy matrix. In this study, sample of Inconel 718 fabricated with SLM method were solution heat-treated to 1100 °C or 1250 °C at different hold times to investigate the dissolution of macro- and micro-segregated precipitates. Investigations of microstructure and segregation in as-printed and solution heat-treated states have been studied using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Optical Microscopy (OM). Measurement of material hardness was performed with Vickers hardness tests. The microstructure of the as-printed parts exhibit non-columnar grains, but contain well-shaped columnar/cellular sub-grains. The intergranular boundaries are decorated with high density of dislocations and segregated particles. Tremendous stress relief and grain coarsening were observed with solution heat treatment. In particular, at 1250 °C annealing, the sub-grains, including precipitates and dislocation networks along the sub-grain boundaries, were entirely dissolved. However, the 1100/1250 °C solution heat treatment scheme could not dissolve microsegregated precipitates and carbides completely. Details of the analysis on microstructure, dissolution of precipitates and hardness are presented.

Effect of titanium implantation on the mechanical properties of silicon nitride

International Nuclear Information System (INIS)

Fujihana, T.; Nishimura, O.; Yabe, K.; Hayashi, H.; Iwaki, M.

1995-01-01

A study has been made of the chemical composition and mechanical properties of Ti + -implanted Si 3 N 4 surface layers. Implantation of 48 Ti + was performed with doses ranging from 10 15 to 10 17 ions cm -2 at an energy of 150 keV, and at nearly room temperature. XPS was used to analyze the depth dependence of atomic fraction and chemical bonding states of Ti + -implanted layers. The near-surface hardness was measured by a Vickers hardness tester. The friction and wear properties were measured under unlubricated conditions at room temperature using a pin on disk-plane and a block on wheel-periphery configurations, in which the pin and wheel used were AISI 1045 and ASTM W1-9, respectively. Implanted Ti-atoms formed a gaussian distribution predicted by the range theory. At the average projected range, most of Ti-atoms existed as a metallic state and TiN bonding was also formed. Oxygen and carbon were found near the surface layers. In addition to the surface peak, O-atoms accumulated in front of the average projected range of Ti. Such O-atoms formed bonds of Si-oxides and Ti-oxides. Carbon existed as a graphitic state. With increasing a Ti dose, the near-surface hardness decreased, and the wear rate increased at the running-in stage having the high friction coefficient. The steady wear attributed to the stable friction coefficient appeared after the running-in stage, although such a stable stage was not observed for unimplanted Si 3 N 4 . The mechanism for the change in mechanical properties of Si 3 N 4 induced by Ti + -implantation will be discussed in relation to XPS characteristics

Effects of tempering temperature on microstructural evolution and mechanical properties of high-strength low-alloy D6AC plasma arc welds

Energy Technology Data Exchange (ETDEWEB)

Lin, Chun-Ming, E-mail: chunming@ntut.edu.tw [Department of Mechanical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan (China); Lu, Chi-Hao [Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei 10673, Taiwan (China)

2016-10-31

This study prepared high-strength low-alloy (HSLA) D6AC weldments using a plasma arc welding (PAW) process. The PAW weldments were then tempered at temperatures of 300 °C, 450 °C, and 600 °C for 1000 min. Microstructural characteristics of the weld in as-welded HSLA-D6AC, tempered D6AC, and tensile-tested D6AC were observed via optical microscopy (OM). We also investigated the hardness, tensile strength, and V-notched tensile strength (NTS) of the tempered specimens using a Vickers hardness tester and a universal testing machine. The fracture surfaces of the specimens were observed using a scanning electron microscope (SEM). Our results show that the mechanical properties and microstructural features of the HSLA weldments are strongly dependent on tempering temperature. An increase in tempering temperature led to a decrease in the hardness and tensile strength of the weldments but led to an increase in ductility. These effects can be attributed to the transformation of the microstructure and its effect on fracture characteristics. The specimens tempered at 300 °C and 450 °C failed in a ductile-brittle manner due to the presence of inter-lath austenite in the microstructure. After tempering at a higher temperature of 600 °C, martensite embrittlement did not occur, such that specimens failure was predominantly in a ductile manner. In the NTS specimens, an increase in tempering temperature led to a reduction in tensile strength due to notch embrittlement and the effects of grain boundary thickening and sliding. Our findings provide a valuable reference for the application of HSLA-D6AC steel in engineering and other fields.

Laser shock processing on microstructure and hardness of polycrystalline cubic boron nitride tools with and without nanodiamond powders

International Nuclear Information System (INIS)

Melookaran, Roslyn; Melaibari, Ammar; Deng, Cheng; Molian, Pal

2012-01-01

Highlights: ► Laser shock waves hardened polycrystalline cubic boron nitride tools by up to 15%. ► Laser shock waves can build layer-by-layer of nanodiamond to form micro-diamond tools. ► Multiple laser shocks induce significant phase transitions in cBN and nanodiamond. -- Abstract: High amplitude, short duration shock waves created by a 1064 nm, 10 ns Q-switched Nd:YAG laser were used to increase the hardness as well as build successive layers of nanodiamond on sintered polycrystalline cubic boron nitride (PcBN) tools. Multiple scans of laser shocking were applied. Scanning electron microscopy, Raman spectroscopy, Tukon microhardness tester, and optical surface profilometer were used to evaluate the microstructure, phase change, Vicker’s microhardness and surface roughness. Results indicated that laser shock processing of plain PcBN changed the binder concentration, caused phase transition from cubic to hexagonal form, increased the hardness, and almost unaffected surface roughness. Laser shock wave sintering of nanodiamond powders on PcBN resulted in deagglomeration and layer-by-layer build-up of nanoparticles for a thickness of 30 μm inferring that a novel solid freeform technique designated as “shock wave induced freeform technique (SWIFT)” is being discovered for making micro-tools. Depending on the number of multiple laser shocks, the hardness of nanodiamond compact was lower or higher than that of PcBN. It is hypothesized that nanodiamond particles could serve as crack deflectors, increasing the fracture toughness of PcBN.

Combining Ability in Wheat for Seedling Traits by Line X Tester Analysis Under Saline Conditions

Directory of Open Access Journals (Sweden)

Muhammad Osaf

Full Text Available A line × tester analysis involving five varieties SQ-26, SQ-77, GH-10, 8670, PARC-N2 (lines and three varieties 8721, SARC-5 and DN-4 (testers were crossed to study some hydroponics growing characters. In controlled conditions SQ-26 exhibited the highest positive GCA effects on Shoot length, Shoot fresh weight, Na+ and K+ concentrations, while SQ-77 showed maximum GCA effects on Root length, Root fresh weight and Shoot dry weight in females and in males and both DN-4 and SARC-5 showed the highest GCA effects. Under high saline concentration female SQ-77 showed the maximum positive effects on all characters but on shoot length and Na concentration while male SARC-5 exhibited the highest positive GCA effects on all characters. Under high saline level, the cross combination SQ-26 × 8721 showed SCA effects for shoot length, whereas 8670 x 8721 showed the same effects for shoot fresh weight, root fresh weight and root dry weight. For Na+ and K+ concentrations, the cross combination GH-10 × DN-4 showed then highest SCA effects, whereas for shoot dry weight and root length, the cross combinations GH-10 × SARC-5 and PARC-N2 × 8721 showed the highest SCA effects, respectively.

Improvement of the mechanical, tribological and antibacterial properties of glass ionomer cements by fluorinated graphene.

Science.gov (United States)

Sun, Li; Yan, Zhuanjun; Duan, Youxin; Zhang, Junyan; Liu, Bin

2018-06-01

The aim of this study was to improve the mechanical properties, wear resistance and antibacterial properties of conventional glass ionomer cements (GICs) by fluorinated graphene (FG), under the premise of not influencing their solubility and fluoride ion releasing property. FG with bright white color was prepared using graphene oxide by a hydrothermal reaction. Experimental modified GICs was prepared by adding FG to the traditional GICs powder with four different weight ratios (0.5wt%, 1wt%, 2wt% and 4wt%) using mechanical blending. Compressive and flexural strength of each experimental and control group materials were investigated using a universal testing machine. The Vickers microhardness of all the specimens was measured by a Vicker microhardness tester. For tribological properties of the composites, specimens of each group were investigated by high-speed reciprocating friction tester. Fluoride ion releasing was measured by fluoride ion selective electrode methods. The antibacterial effect of GICs/FG composites on selected bacteria (Staphylococci aureus and Streptococcus mutans) was tested with pellicle sticking method. The prepared GICs/FG composites with white color were successfully fabricated. Increase of Vickers microhardness and compressive strength and decrease of friction coefficient of the GICs/FG composites were achieved compared to unreinforced materials. The colony count against S. aureus and S. mutans decreased with the increase of the content of FG. And the antibacterial rate of S. mutans can be up to 85.27% when the FG content was 4wt%. Additionally, fluoride ion releasing property and solubility did not show significant differences between unreinforced and FG reinforced GICs. Adding FG to traditional GICs could not only improve mechanical and tribological properties of the composites, but also improve their antibacterial properties. In addition, the GICs/FG composites had no negative effect on the color, solubility and fluoride ion releasing

Effect of implanted helium on tensile properties and hardness of 9% Cr martensitic stainless steels

Science.gov (United States)

Jung, P.; Henry, J.; Chen, J.; Brachet, J.-C.

2003-05-01

Hundred micrometer thick specimens of 9% Cr martensitic steels EM10 and T91 were homogeneously implanted with He 4 to concentrations up to 0.5 at.% at temperatures from 150 to 550 °C. The specimens were tensile tested at room temperature and at the respective implantation temperatures. Subsequently the fracture surfaces were analysed by scanning electron microscopy and some of the specimens were examined in an instrumented hardness tester. The implanted helium caused hardening and embrittlement which both increased with increasing helium content and with decreasing implantation temperature. Fracture surfaces showed intergranular brittle appearance with virtually no necking at the highest implantation doses, when implanted below 250 °C. The present tensile results can be scaled to tensile data after irradiation in spallation sources on the basis of helium content but not on displacement damage. An interpretation of this finding by microstructural examination is given in a companion paper [J. Nucl. Mater., these Proceedings].

Plasma spray formed near-net-shape MoSi2-Si3N4 bulk nanocomposites-structure property evaluation

International Nuclear Information System (INIS)

Hong, S.J.; Viswanathan, V.; Rea, K.; Patil, S.; Deshpande, S.; Georgieva, P.; McKechnie, T.; Seal, S.

2005-01-01

This article, for the first time, presents the challenges toward the successful consolidation of near-net-shape bulk MoSi 2 -Si 3 N 4 -SiC nanocomposite using plasma spray forming. A detailed characterization of the spray formed bulk nanocomponent has been performed using optical microscopy (OM), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and Vickers hardness testing. Vickers hardness (900 Hv) and fracture toughness (∼>5 MPa m 1/2 ) of the nanocomposite showed a little deviation from the expected, which might be due to the difference in the particle (Si 3 N 4 ) size and their distribution in the MoSi 2 matrix as a function of component thickness. Relatively higher hardness is attributed to the retention of the nanostructure in the composite. In addition, the as fabricated bulk nanocomposite showed enhanced oxidation resistance

Evaluation of a Degradation of Thermal Barrier Coating for Gas Turbine Blade

Energy Technology Data Exchange (ETDEWEB)

Kim, Dae Jin; Lee, Dong Hoon; Koo, Jae Mean; Seok, Chang Sung [Sungkyunkwan Univ., Seoul (Korea, Republic of); Kim, Mun Young; Yang, Sung Ho; Park, Sang Yoel [Korea Power Engineering Company, Inc., Yongin (Korea, Republic of)

2007-07-01

Thermal barrier coating system for gas turbine blade were thermally aged by isothermal heating in the furnace varing aging time and temperature. Then, micro Vickers hardness test was done for the cross section of bond coat and Ni-based superalloy substrate. Also, the thickness of TGO was measured by image analyzer and the changes in the microstructure and element distributions in the coating were analyzed by optical microscope and SEM-EDX analysis. No significant changes in the Vickers hardness of the bond coat were observed as the coated specimen was aged at high temperature and delaminations near between top coat and bond coat occurred when the coatings were aged for 50 hr at over 1,151 .deg. C.

Hardness Optimization for Al6061-MWCNT Nanocomposite Prepared by Mechanical Alloying Using Artificial Neural Networks and Genetic Algorithm

Directory of Open Access Journals (Sweden)

Mehrdad Mahdavi Jafari

2017-06-01

Full Text Available Among artificial intelligence approaches, artificial neural networks (ANNs and genetic algorithm (GA are widely applied for modification of materials property in engineering science in large scale modeling. In this work artificial neural network (ANN and genetic algorithm (GA were applied to find the optimal conditions for achieving the maximum hardness of Al6061 reinforced by multiwall carbon nanotubes (MWCNTs through modeling of nanocomposite characteristics. After examination the different ANN architectures an optimal structure of the model, i.e. 6-18-1, is obtained with 1.52% mean absolute error and R2 = 0.987. The proposed structure was used as fitting function for genetic algorithm. The results of GA simulation predicted that the combination sintering temperature 346 °C, sintering time 0.33 h, compact pressure 284.82 MPa, milling time 19.66 h and vial speed 310.5 rpm give the optimum hardness, (i.e., 87.5 micro Vickers in the composite with 0.53 wt% CNT. Also, sensitivity analysis shows that the sintering time, milling time, compact pressure, vial speed and amount of MWCNT are the significant parameter and sintering time is the most important parameter. Comparison of the predicted values with the experimental data revealed that the GA–ANN model is a powerful method to find the optimal conditions for preparing of Al6061-MWCNT.

The use of the durometer to measure rock hardness in geomorphology. Advantages and limitations.

Science.gov (United States)

Feal-Pérez, Alejandra; Blanco-Chao, Ramón; Valcarcel-Díaz, Marcos; Combes, Martín. A.

2010-05-01

The durometer is a hardness tester developed to measure hardness of metallic materials that has been recently introduced to measure rock hardness in weathering studies. Aoki & Matsukura (2007) highlight some advantages of the durometer compared with the Schmidt Rock Test Hammer: the smaller plunge allows measurements in small surfaces such as taffoni or rock carvings, the wider measurement range and the lower impact energy. This last makes it a non destructive method that can be used on relatively soft rocks. In this work the durometer Equotip (©) has been tested in different environments in the field and in the laboratory to explore its applicability and limitations. We applied the device on small rock samples of granite and limestone and a T-test showed that smaller sample size gave smaller hardness values (p values obtained inside and outside the grooves of the carvings using two different support rings, one flat and one concave. The flat ring was not able to reach the bottom of the groove, meanwhile the concave ring adjusts fairly well given its semi spherical section. A t-test confirmed the difference (p values obtained in the grooves using the flat ring and the higher and less scattered values obtained when the concave ring is used. As a very sensitive device, there are some problems in the use related with rock roughness and rock grain size. In weathered medium to coarse grained rocks, with very irregular surfaces, is not easy to get a good contact between the plunge and the rock surface. A poor contact caused by surface roughness causes the scattering and lowering of rebound values. On the contrary, in homogeneous fine grained rocks and in uniform rock surfaces the device gave very good results. The data obtained in glacial, nival and rock coastal environments showed the potential of the device in the identification of changes in rock hardness. We were able to asses the changes in the weathering degree of glacial striations and marked differences in the

Effect of multiple repairs in girth welds of pipelines on the mechanical properties

International Nuclear Information System (INIS)

Vega, O.E.; Hallen, J.M.; Villagomez, A.; Contreras, A.

2008-01-01

This work presents the results of multiple weld repairs in the same area in seamless API X-52 microalloyed steel pipe. Four conditions of shielded metal arc welding repairs and one as-welded specimen of the girth weld were characterized to determine changes in the microstructure, grain size in the heat affected zone, and to evaluate their effect on the mechanical properties of the weld joints. The mechanical properties by means of tension tests, Charpy-V impact resistance and Vickers hardness of the welds were analyzed. The results indicate that significant changes are not generated in the microstructural constituents of the heat affected zone. Grain growth in the heat affected zone at the specimen mid-thickness with the number of repairs was observed. Tensile strength of the weld joints meets the requirement of the API 1104 standard even after the fourth weld repair. Significant reduction in Charpy-V impact resistance with the number of weld repairs was found when the notch location was in the intersection of the fusion line with the specimen mid-thickness. A significant increase in the Vickers hardness of the heat affected zone occurred after the first repair and a gradual decrease in the Vickers hardness occurred as the number of repairs increases

Effects of sintering temperature on the mechanical properties of sintered NdFeB permanent magnets prepared by spark plasma sintering

International Nuclear Information System (INIS)

Wang, G.P.; Liu, W.Q.; Huang, Y.L.; Ma, S.C.; Zhong, Z.C.

2014-01-01

Sintered NdFeB-based permanent magnets were fabricated by spark plasma sintering (SPS) and a conventional method to investigate the mechanical and magnetic properties. The experimental results showed that sintered NdFeB magnet prepared by the spark plasma sintering (SPS NdFeB) possesses a better mechanical properties compared to the conventionally sintered one, of which the maximum value of bending strength and Vickers hardness was 402.3 MPa and 778.1 MPa, respectively. The effects of sintering temperature on bending strength and Vickers hardness were investigated. It was shown that the bending strength firstly increases to the maximum value and then decreases with the increase of sintering temperature in a certain range. The investigations of microstructures and mechanical properties indicated that the unique sintering mechanism in the SPS process is responsible for the improvement of mechanical properties of SPS NdFeB. Furthermore, the relations between the mechanical properties and relevant microstructure have been analyzed based on the experimental fact. - Highlights: • Studied the sintering temperature effect on strengthening mechanism of NdFeB magnet firstly. • It showed that sintering temperature may effectively affect the mechanical properties. • The maximum bending strength and Vickers hardness was 402.3 MPa and 778.1 MPa, respectively

Effects of sintering temperature on the mechanical properties of sintered NdFeB permanent magnets prepared by spark plasma sintering

Energy Technology Data Exchange (ETDEWEB)

Wang, G.P., E-mail: wgp@jxnu.edu.cn [College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022 (China); Liu, W.Q. [Key Laboratory of Advanced Functional Materials Science and Engineering, Ministry of Education, Beijing University of Technology, Beijing 100022 (China); Huang, Y.L.; Ma, S.C.; Zhong, Z.C. [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

2014-01-15

Sintered NdFeB-based permanent magnets were fabricated by spark plasma sintering (SPS) and a conventional method to investigate the mechanical and magnetic properties. The experimental results showed that sintered NdFeB magnet prepared by the spark plasma sintering (SPS NdFeB) possesses a better mechanical properties compared to the conventionally sintered one, of which the maximum value of bending strength and Vickers hardness was 402.3 MPa and 778.1 MPa, respectively. The effects of sintering temperature on bending strength and Vickers hardness were investigated. It was shown that the bending strength firstly increases to the maximum value and then decreases with the increase of sintering temperature in a certain range. The investigations of microstructures and mechanical properties indicated that the unique sintering mechanism in the SPS process is responsible for the improvement of mechanical properties of SPS NdFeB. Furthermore, the relations between the mechanical properties and relevant microstructure have been analyzed based on the experimental fact. - Highlights: • Studied the sintering temperature effect on strengthening mechanism of NdFeB magnet firstly. • It showed that sintering temperature may effectively affect the mechanical properties. • The maximum bending strength and Vickers hardness was 402.3 MPa and 778.1 MPa, respectively.

On the quench sensitivity of 7010 aluminum alloy forgings in the overaged condition

Energy Technology Data Exchange (ETDEWEB)

Tiryakioğlu, Murat, E-mail: m.tiryakioglu@unf.edu [School of Engineering, University of North Florida, Jacksonville, FL 32224 (United States); Robinson, Jeremy S. [Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick, Limerick (Ireland); Eason, Paul D. [School of Engineering, University of North Florida, Jacksonville, FL 32224 (United States)

2014-11-17

The quench sensitivity of an overaged 7010 alloy forging was characterized by tensile and Vickers hardness tests, as well as scanning electron microscopy. Longitudinal tensile specimens, excised from a rectilinear open die forging were cooled from the solution treatment temperature following thirty-two different cooling paths including interrupted and delayed quenches. SEM analysis of the microstructure showed that quench precipitates were (i) Al{sub 2}CuMg (S) which nucleated heterogeneously on grain boundaries and (ii) Mg(Zn,Cu,Al){sub 2} (η) on grain boundaries, dispersoid bands, subgrain boundaries as well as in the aluminum matrix. The quench sensitivity of the alloy's yield strength and Vickers hardness was modeled simultaneously by quadruple-C curves, using an improved methodology for Quench Factor Analysis. The four C-curves used in the model represented loss of solute by (i) precipitation of S on grain boundaries, and precipitation of η (ii) on grain boundaries and dispersoid bands, (iii) on subgrain boundaries and (iv) in the matrix. The model yielded coefficient of determination (R{sup 2}) values of 0.967 and 0.974 for yield strength and Vickers hardness, respectively. The model and the implications of the results are discussed in this paper.

Manufacturing Feasibility and Forming Properties of Cu-4Sn in Selective Laser Melting.

Science.gov (United States)

Mao, Zhongfa; Zhang, David Z; Wei, Peitang; Zhang, Kaifei

2017-03-24

Copper alloys, combined with selective laser melting (SLM) technology, have attracted increasing attention in aerospace engineering, automobile, and medical fields. However, there are some difficulties in SLM forming owing to low laser absorption and excellent thermal conductivity. It is, therefore, necessary to explore a copper alloy in SLM. In this research, manufacturing feasibility and forming properties of Cu-4Sn in SLM were investigated through a systematic experimental approach. Single-track experiments were used to narrow down processing parameter windows. A Greco-Latin square design with orthogonal parameter arrays was employed to control forming qualities of specimens. Analysis of variance was applied to establish statistical relationships, which described the effects of different processing parameters (i.e., laser power, scanning speed, and hatch space) on relative density (RD) and Vickers hardness of specimens. It was found that Cu-4Sn specimens were successfully manufactured by SLM for the first time and both its RD and Vickers hardness were mainly determined by the laser power. The maximum value of RD exceeded 93% theoretical density and the maximum value of Vickers hardness reached 118 HV 0.3/5. The best tensile strength of 316-320 MPa is inferior to that of pressure-processed Cu-4Sn and can be improved further by reducing defects.

Microstructure and tribological property of nanocrystalline Co–W alloy coating produced by dual-pulse electrodeposition

International Nuclear Information System (INIS)

Su Fenghua; Huang Ping

2012-01-01

Highlights: ► The nanocrystalline Co–W alloy coating were produced by dual-pulse electrodeposition from aqueous bath with cobalt sulfate and sodium tungstate. ► The correlation between the electrodeposition condition, the microstructure and alloy composition, and the hardness and tribological properties of electrodeposited Co–W alloy coatings were established. ► By careful control of the electrodeposition condition and the bath composition, the Co–W alloy coating excellent performance of microhardness and tribological properties, can exhibit excellent performances of microhardness and tribological properties. - Abstract: The nanocrystalline Co–W alloy coatings were produced by dual-pulse electrodeposition from aqueous bath with cobalt sulfate and sodium tungstate (Na 2 WO 4 ). Influence of the current density and Na 2 WO 4 concentration in bath on the microstructure, morphology and hardness of the Co–W alloy coatings were investigated using an X-ray diffraction, a scanning electronic microscope and a Vickers hardness tester, respectively. In addition, the friction and wear properties of the Co–W alloy coating electrodeposited under different condition were evaluated with a ball-on-disk UMT-3MT tribometer. The correlation between the electrodeposition condition, the microstructure and alloy composition, and the hardness and tribological properties of the deposited Co–W alloy coatings were discussed in detail. The results showed that the microhardness of the deposited Co–W alloy coating was significantly affected by its average grain size, W content and crystal orientation. Smaller grain size, higher W content and strong hcp (1 0 0) orientation favor the improvement of the hardness for Co–W alloy coatings. The deposited Co–W alloy coating could obtain the maximum microhardness over 1000 kgf mm −2 by careful control of the electrodeposition conditions. The tribological properties of the electrodeposited Co–W alloy coating were greatly

Hardening of ODS ferritic steels under irradiation with high-energy heavy ions

Science.gov (United States)

Ding, Z. N.; Zhang, C. H.; Yang, Y. T.; Song, Y.; Kimura, A.; Jang, J.

2017-09-01

Influence of the nanoscale oxide particles on mechanical properties and irradiation resistance of oxide-dispersion-strengthened (ODS) ferritic steels is of critical importance for the use of the material in fuel cladding or blanket components in advanced nuclear reactors. In the present work, impact of structures of oxide dispersoids on the irradiation hardening of ODS ferritic steels was studied. Specimens of three high-Cr ODS ferritic steels containing oxide dispersoids with different number density and average size were irradiated with high-energy Ni ions at about -50 °C. The energy of the incident Ni ions was varied from 12.73 MeV to 357.86 MeV by using an energy degrader at the terminal so that a plateau of atomic displacement damage (∼0.8 dpa) was produced from the near surface to a depth of 24 μm in the specimens. A nanoindentor (in constant stiffness mode with a diamond Berkovich indenter) and a Vickers micro-hardness tester were used to measure the hardeness of the specimens. The Nix-Gao model taking account of the indentation size effect (ISE) was used to fit the hardness data. It is observed that the soft substrate effect (SSE) can be diminished substantially in the irradiated specimens due to the thick damaged regions produced by the Ni ions. A linear correlation between the nano-hardeness and the micro-hardness was found. It is observed that a higher number density of oxide dispersoids with a smaller average diameter corresponds to an increased resistance to irradiation hardening, which can be ascribed to the increased sink strength of oxides/matrix interfaces to point defects. The rate equation approach and the conventional hardening model were used to analyze the influence of defect clusters on irradiation hardening in ODS ferritic steels. The numerical estimates show that the hardening caused by the interstitial type dislocation loops follows a similar trend with the experiment data.

DETERMINATION OF VICKERS MICROHARDNESS IN β-Ga2O3 SINGLE CRYSTALS GROWN FROM THEIR OWN MELT

Directory of Open Access Journals (Sweden)

L. I. Guzilova

2015-05-01

Full Text Available The results of microhardness measurements of β-Ga2O3 single crystals for (001 crystallographic face are reported. The crystals were grown by the free crystallization with the "Garnet-2M" equipment. Microhardness values ​​ were determined by the Vickers method at varying loads. A four-sided diamond pyramid was used as an indenter. The average value of gallium oxide microhardness was equal to 8.91 GPa. We have carried out comparison of the values ​​obtained with the microhardness for the other wide bandgap semiconductors - epitaxial GaN layers grown on 6H-SiC and GaP layers grown on GaP:S. The findings are usable for machining process development of β-Ga2O3 single crystal substrates. In particular, silicon carbide and electrocorundum may be recommended for β-Ga2O3 machine processing.

Effect of sintering conditions on the microstructural and mechanical characteristics of porous magnesium materials prepared by powder metallurgy.

Science.gov (United States)

Čapek, Jaroslav; Vojtěch, Dalibor

2014-02-01

There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium. © 2013.

Trial of prestressed concrete cable testing by sonic integrity tester

International Nuclear Information System (INIS)

Sugimoto, Masanobu

1997-01-01

Highway road network of Japan is in good condition. Those roads were constructed as social infrastructures. But some damages were occurred and propagated in concrete structure which passed more than 20 years after construction. As for the damages load caring capacity of bridge was decreased due to fatigue of increasing traffics and bridge vibration. Recently many troubles happened in PC structure as cut off of the main cables by corrosion and flying the non-grouting PC-bar to roadside. Some case can be checked by hammering testing method and X-ray photo cut or not and condition of cement grouting. But another case has not checking method. Now we are testing for the PC cables by sonic integrity tester which is modified from FPDS(Foundation Pile Diagnosis System). We report in this paper on this result and scope of the future of this method.

Effects of aging temperature on electrical conductivity and hardness of Cu-3 at. pct Ti alloy aged in a hydrogen atmosphere

KAUST Repository

Semboshi, S.

2011-08-01

To improve the balance of the electrical conductivity and mechanical strength for dilute Cu-Ti alloys by aging in a hydrogen atmosphere, the influence of aging temperature ranging from 673 K to 773 K (400 °C to 500 °C) on the properties of Cu-3 at. pct Ti alloy was studied. The Vickers hardness increases steadily with aging time and starts to fall at 3 hours at 773 K (500 °C), 10 hours at 723 K (450 °C), or over 620 hours at 673 K (400 °C), which is the same as the case of conventional aging in vacuum. The maximum hardness increases from 220 to 236 with the decrease of aging temperature, which is slightly lower than aging at the same temperature in vacuum. The electrical conductivity at the maximum hardness also increases from 18 to 32 pct of pure copper with the decrease of the temperature, which is enhanced by a factor of 1.3 to 1.5 in comparison to aging in vacuum. Thus, aging at 673 K (400 °C) in a hydrogen atmosphere renders fairly good balance of strength and conductivity, although it takes nearly a month to achieve. The microstructural changes during aging were examined by transmission electron microscopy (TEM) and atom-probe tomography (APT), it was confirmed that precipitation of the Cu4Ti phase occurs first and then particles of TiH2 form as the third phase, thereby efficiently removing the Ti solutes in the matrix.

Revisiting the definition of local hardness and hardness kernel.

Science.gov (United States)

Polanco-Ramírez, Carlos A; Franco-Pérez, Marco; Carmona-Espíndola, Javier; Gázquez, José L; Ayers, Paul W

2017-05-17

An analysis of the hardness kernel and local hardness is performed to propose new definitions for these quantities that follow a similar pattern to the one that characterizes the quantities associated with softness, that is, we have derived new definitions for which the integral of the hardness kernel over the whole space of one of the variables leads to local hardness, and the integral of local hardness over the whole space leads to global hardness. A basic aspect of the present approach is that global hardness keeps its identity as the second derivative of energy with respect to the number of electrons. Local hardness thus obtained depends on the first and second derivatives of energy and electron density with respect to the number of electrons. When these derivatives are approximated by a smooth quadratic interpolation of energy, the expression for local hardness reduces to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba. However, when one combines the first directional derivatives with smooth second derivatives one finds additional terms that allow one to differentiate local hardness for electrophilic attack from the one for nucleophilic attack. Numerical results related to electrophilic attacks on substituted pyridines, substituted benzenes and substituted ethenes are presented to show the overall performance of the new definition.

Radioprotective action of glycerol and cysteamine on inactivation and mutagenesis in Salmonella tester strains after gamma and heavy ion irradiation

International Nuclear Information System (INIS)

Basha, S.G.; Krasavin, E.A.; Kozubek, S.

1991-01-01

Inactivation and mutagenesis were studied in Salmonella tester strains after γ-irradiation and after heavy ion irradiation in the presence of glycerol and cysteamine. Bacterial cells were irradiated at Dubna, JINR. Ions from deuterons to carbon were used with residual energies 2-9 MeV/u. The protective effect of glycerol was found both for γ-radiation and for heavy ions up to 50 keV/μm for both cell inactivation and mutagenesis in Salmonella tester strains with different mutation events. Cell sensitivity slightly increased with LET before falling down. The maximum was shifted in the presence of glycerol to the left and was less pronounced. The radioprotective effect of glycerol diminished gradually with LET from 2.0 for γ-radiation to 1.1 for carbon ions. Mutagenesis increases with LET in TA100 strain; in TA98 strain no marked increase could be detected. 13 refs.; 4 figs.; 5 tabs

LVDS tester: a systematic test of cable signal transmission at the ALICE experiment

CERN Document Server

Barnby, L; Bombara, M; Evans, D; Jones, G T; Jones, P G; Jovanović, P; Jusko, A; Kour, R; Králik, I; Krivda, M; Lazzeroni, C; Lietava, R; Matthews, Z L; Navin, S; Palaha, A; Petrov, P; Platt, R; Šándor, L; Scott, P; Urbán, J; Villalobos Baillie, O; Tapia Takaki, J D

2010-01-01

In the ALICE experiment, the Low-Voltage Differential Signalling (LVDS) format is used for the transmission of trigger inputs from the detectors to the Central Trigger Processor (CTP), the L0 trigger outputs from Local Trigger Units (LTU) boards back to the detectors and the BUSY inputs from the sub-detectors to the CTP. ALICE has designed a set-up, called the LVDS transmission tester, that aims to measure various transmission quality parameters and the bit-error rate (BER) for long period runs in an automatic way. In this paper, this method is described and the conclusions from these tests for the ALICE LVDS cables are discussed

LVDS tester: a systematic test of cable signal transmission at the ALICE experiment

International Nuclear Information System (INIS)

Barnby, L; Bhasin, A; Evans, D; Jones, G T; Jones, P G; Jovanovic, P; Jusko, A; Kour, R; Krivda, M; Lazzeroni, C; Lietava, R; Matthews, Z L; Navin, S; Palaha, A; Petrov, P; Platt, R; Scott, P; Bombara, M; Kralik, I; Sandor, L

2010-01-01

In the ALICE experiment, the Low-Voltage Differential Signalling (LVDS) format is used for the transmission of trigger inputs from the detectors to the Central Trigger Processor (CTP), the L0 trigger outputs from Local Trigger Units (LTU) boards back to the detectors and the BUSY inputs from the sub-detectors to the CTP. ALICE has designed a set-up, called the LVDS transmission tester, that aims to measure various transmission quality parameters and the bit-error rate (BER) for long period runs in an automatic way. In this paper, this method is described and the conclusions from these tests for the ALICE LVDS cables are discussed.

Tensile and fracture toughness characteristics of Zr-2.5Nb pressure tube

International Nuclear Information System (INIS)

Jung, H. C.; Kim, Y. S.; Ahn, S. B.; Kim, S. S.; Im, K. S.

2004-01-01

The object of this study is to evaluate the characteristics of tensile and fracture toughness of Zr-2.5Nb pressure tube. The transverse tensile tests were performed at various temperatures and the fracture toughness tests were carried out at room temperature using the CCT (curved compact tension) specimen. These specimens were directly machined from the pressure tube retaining original curvatures. Also, the fracture toughness of two sets of Zr-2.5Nb manufactured at different time was compared. The chemical analysis and the Vicker's hardness tests were performed at two sets of Zr-2.5Nb pressure tube. The Vicker's hardness value of SET-2 containing more oxygen and carbon relatively was higher about 11 than that of SET-1

Investigation on the growth, spectral, lifetime, mechanical analysis and third-order nonlinear optical studies of L-methionine admixtured D-mandelic acid single crystal: A promising material for nonlinear optical applications

Science.gov (United States)

Jayaprakash, P.; Sangeetha, P.; Kumari, C. Rathika Thaya; Caroline, M. Lydia

2017-08-01

A nonlinear optical bulk single crystal of L-methionine admixtured D-mandelic acid (LMDMA) has been grown by slow solvent evaporation technique using water as solvent at ambient temperature. The crystallized LMDMA single crystal subjected to single crystal X-ray diffraction study confirmed monoclinic system with the acentric space group P21. The FTIR analysis gives information about the modes of vibration in the various functional groups present in LMDMA. The UV-visible spectral analysis assessed the optical quality and linear optical properties such as extinction coefficient, reflectance, refractive index and from which optical conductivity and electric susceptibility were also evaluated. The frequency doubling efficiency was observed using Kurtz Perry powder technique. A multiple shot laser was utilized to evaluate the laser damage threshold energy of the crystal. Discrete thermodynamic properties were carried out by TG-DTA studies. The hardness, Meyer's index, yield strength, elastic stiffness constant, Knoop hardness, fracture toughness and brittleness index were analyzed using Vickers microhardness tester. Layer growth pattern and the surface defect were examined by chemical etching studies using optical microscope. Fluorescence emission spectrum was recorded and lifetime was also studied. The electric field response of crystal was investigated from the dielectric studies at various temperatures at different frequencies. The third-order nonlinear optical response in LMDMA has been investigated using Z-scan technique with He-Ne laser at 632.8 nm and nonlinear parameters such as refractive index (n2), absorption coefficient (β) and susceptibility (χ3) investigated extensively for they are in optical phase conjucation, high-speed optical switches and optical dielectric devices.

The effectiveness of betel leaf (Piper betle Linn extract gel and cocoa bean (Theobroma cacao L extract gel application against the hardness of enamel surface in vitro.

Directory of Open Access Journals (Sweden)

Juni Jekti Nugroho

2017-04-01

Full Text Available Objective : Nowadays several ways  have been evolved  to increase the hardness of the enamel surface as an effort to prevent caries. One of the alternatives that can be used is application of gel with herbal basic material. Material and Methods : The use of herbal basic material is preferred by people because the side effects are relatively small compared to synthetic drugs. Piper betle and cocoa beans are medicinal plants that is often used by people to inhibit caries. This is because piper betle and cocoa beans contain hardness that may influence the enamel surface. The purpose of this research was to determine the effect of piper betle extract gel and cocoa bean extract gel against the hardness of enamel surface. The samples, maxillary first premolar teeth, which has been extracted and does not have caries, were divided into 3 treatment groups: piper betle extract gel, cocoa bean extract gel, and distilled water as a negative control. Each treatment group consisted of 8 samples. The samples are decoronated in cemento-enamel junction (CEJ areas and planted on orthoplast blocks with labial surface facing up. Samples were applied in labial enamel surface to 5, 15 and 35 minutes period times. Samples before and after the application in each treatment group were measured using Universal Hardness Tester. Data were collected and analyzed using ANNOVA Repeated test. Results : Showed there were significant differences (p 0.05 of enamel surface hardness before and after the application of piper betel extract gel and distilled water. Conclusion : Therefore it can be concluded that cocoa been extract gel is more effective to increase the hardness of email surface.

Crack-resistant Al2O3-SiO2 glasses.

Science.gov (United States)

Rosales-Sosa, Gustavo A; Masuno, Atsunobu; Higo, Yuji; Inoue, Hiroyuki

2016-04-07

Obtaining "hard" and "crack-resistant" glasses have always been of great important in glass science and glass technology. However, in most commercial glasses both properties are not compatible. In this work, colorless and transparent xAl2O3-(100-x)SiO2 glasses (30 ≤ x ≤ 60) were fabricated by the aerodynamic levitation technique. The elastic moduli and Vickers hardness monotonically increased with an increase in the atomic packing density as the Al2O3 content increased. Although a higher atomic packing density generally enhances crack formation in conventional oxide glasses, the indentation cracking resistance increased by approximately seven times with an increase in atomic packing density in binary Al2O3-SiO2 glasses. In particular, the composition of 60Al2O3 • 40SiO2 glass, which is identical to that of mullite, has extraordinary high cracking resistance with high elastic moduli and Vickers hardness. The results indicate that there exist aluminosilicate compositions that can produce hard and damage-tolerant glasses.

The characterization of Vicker's microhardness indentations and pile-up profiles as a strain-hardening microprobe

International Nuclear Information System (INIS)

Santos, C. Jr.

1998-04-01

Microhardness measurements have long been used to examine strength properties and changes in strength properties in metals, for example, as induced by irradiation. Microhardness affords a relatively simple test that can be applied to very small volumes of material. Microhardness is nominally related to the flow stress of the material at a fixed level of plastic strain. Further, the geometry of the pile-up of material around the indentation is related to the strain-hardening behavior of a material; steeper pile-ups correspond to smaller strain-hardening rates. In this study the relationship between pile-up profiles and strain hardening is examined using both experimental and analytical methods. Vickers microhardness tests have been performed on a variety of metal alloys including low alloy, high Cr and austenitic stainless steels. The pile-up topology around the indentations has been quantified using confocal microscopy techniques. In addition, the indentation and pile-up geometry has been simulated using finite element method techniques. These results have been used to develop an improved quantification of the relationship between the pile-up geometry and the strain-hardening constitutive behavior of the test material

Evaluation of mechanical properties of recasted dental base metal alloys for considering their reusability in dentistry and engineering field

Directory of Open Access Journals (Sweden)

Nandish Bantarahalli Thopegowda

2014-01-01

Full Text Available Background: Base metal casting alloys are extensively used in dentistry to fabricate many oral appliances and a huge amount is wasted in the form of sprues and buttons during the casting procedure. Recycling and reusing these alloys by clean technologies may save our natural resources from being depleted and as well reduce the cost of the treatment of the patients. Objectives: To study the mechanical properties of recasted dental base metal alloys, and explore possible ways to recycle and reuse in dentistry and other fields of science and technology. Materials and Methods: Two beryllium-free Cobalt-Chromium (Co-Cr dental casting alloys, Wironit and Wirobond-C, were used for this study. Six groups of specimen (melted once, twice, five, ten, fifteen and twenty times per each alloy were casted. The tensile strength and hardness of these samples were measured by using universal testing machine and Vickers hardness number (VHN tester. Results: Tensile strength decreased from 850 MPa to 777 MPa after 5 th recasting and to 674 MPa at the end of 20 th recasting procedure for the Wironit samples. For Wirobond-C samples, tensile strength decreased from 720 MPa to 678 MPa after 5 th recasting and further reduced to 534 MPa at the end of 20 th recasting procedure. Hardness decreased from 380VHN to 335VHN at the end of 20 th recasting for Wironit samples and 328VHN to 247VHN for Wirobond-C samples after 20 th recasting procedure. The slight decrease in their mechanical properties will not have any impact on the clinical performance for dental applications. Conclusion: There is no major degradation in the mechanical properties after recycling, and hence, the left over alloys after casting procedures can be reused in dentistry with a condition to satisfy cytotoxicity tests.

Evaluation of crystalline changes and resistance to demineralization of the surface of human dental enamel treated with Er:YAG laser and fluoride using x-ray diffraction analysis and Vickers microhardness

Science.gov (United States)

Behroozibakhsh, Marjan; Shahabi, Sima; Ghavami-Lahiji, Mehrsima; Sadeghian, Safura; Sadat Faal Nazari, Neda

2018-06-01

This study aimed to investigate the changes in crystalline structure and resistance to demineralization of human dental surface enamel treated with erbium-doped yttrium aluminium garnet laser (Er:YAG) laser and fluoride. The enamel surfaces were divided into four groups according to the treatment process including, (L): irradiated with Er:YAG; (F): treated with acidulated phosphate fluoride gel (LF): Pre-irradiated surfaces with Er:YAG subjected to acidulated phosphate fluoride gel and (FL): laser irradiation was performed on the fluoridated enamel surface. Before and after the treatment procedure, the samples were evaluated using X-ray diffraction, scanning electron microscope (SEM) and the Vickers microhardness test. The surface microhardness values also were measured after a pH-cycling regime and acid challenge. The a-axis of all lased groups was contracted after treatment procedure. Measurement of the area under the peaks showed the highest crysallinity in the FL group. The hardness values of all laser treated samples significantly reduced after treatment procedure compared to the F group (p  ⩽  0.001). The morphological observations showed remarkable changes on the lased enamel surfaces including cracks, craters and exposed prisms. These findings suggest, irradiation of the Er:YAG laser accompanying with fluoride application can induce some beneficial crystalline changes regarding the acid-resistance properties of enamel, however, the craters and cracks produced by laser irradiation can promote enamel demineralization and consequently the positive effects of the Er:YAG laser will be eliminated.

Characterization of the Interface of an Alloy 625 Overlay on Steels Using Nanoindentation

Science.gov (United States)

Dai, Tao; Lippold, John

2018-06-01

Industry standards require postweld heat treatment (PWHT) to reduce the heat-affected zone hardness of steels such as F22 (2.25Cr-1Mo) and AISI 8630 overlaid (clad) with Alloy 625 weld metal. PWHT results in carbon diffusion and accumulation at the interface between the steel and overlay. The accumulation of carbon in a planar solidification growth zone adjacent to the fusion boundary results in high hardness and the potential for hydrogen-assisted cracking. The planar growth zone (PGZ) is so narrow that normal Vickers hardness testing cannot fully reveal the hardness distribution in this zone. This study focused on the application of nanoindentation to characterize the hardness in the narrow microstructural regions adjacent to the fusion boundary. The development of nanohardness maps revealed that the PGZ is not necessarily the region that exhibits peak hardness after PWHT. The highest hardness values were associated with clusters of M7C3 carbides in specific subregions in the PGZ and also in the partially-mixed zone adjacent to the fusion boundary or in steel "swirl" structures. It was also confirmed in this study that nanohardness has a linear correlation with Vickers hardness values. The results presented here provide new insight into the role of carbon diffusion during PWHT and its effect on interface embrittlement associated with Alloy 625 overlays on steel.

Testing parameters of TMR heads affected by dynamic-tester induced EMI

International Nuclear Information System (INIS)

Kruesubthaworn, A.; Sivaratana, R.; Ungvichian, V.; Siritaratiwat, A.

2007-01-01

A variety of expected electromagnetic interference (EMI) sources of both radiated and conducted EMI emissions produced by a dynamic tester is studied. It is determined that the power cable connector of the robot arm radiates a significant electric field (E-field) of about 197 V/m at 1 foot away and an estimated calculation of the E-field of about 212 mV/m is at the spindle motor. These fields can be attenuated by about 20-30 dB when using a copper lined Faraday's cage. Furthermore, the study has revealed that the radiated EMI plays a more significant role than the conducted EMI. In addition, it is determined that out of seven selected testing parameters, the SGAW is rather more sensitive to EMI than conventional failure parameters, especially static glitche during the write cycle

Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester (IQT)

KAUST Repository

Naser, Nimal

2016-09-21

A methodology for estimating the octane index (OI), the research octane number (RON) and the motor octane number (MON) using ignition delay times from a constant volume combustion chamber with liquid fuel injection is proposed by adopting an ignition quality tester. A baseline data of ignition delay times were determined using an ignition quality tester at a charge pressure of 21.3 bar between 770 and 850 K and an equivalence ratio of 0.7 for various primary reference fuels (PRFs, mixtures of isooctane and n-heptane). Our methodology was developed using ignition delay times for toluene reference fuels (mixtures of toluene and n-heptane). A correlation between the OI and the ignition delay time at the initial charge temperature enabled the OI of non-PRFs to be predicted at specified temperatures. The methodology was validated using ignition delay times for toluene primary reference fuels (ternary mixtures of toluene, iso-octane, and n-heptane), fuels for advanced combustion engines (FACE) gasolines, and certification gasolines. Using this methodology, the RON, the MON, and the octane sensitivity were estimated in agreement with values obtained from standard test methods. A correlation between derived cetane number and RON is also provided. (C) 2016 Elsevier Ltd. All rights reserved.

In vitro Comparison of the Effct Cola Beverage on Surface Hardness of Siloran-Based (p90 and Methyl Methacrylate-Based (p60 Composites

Directory of Open Access Journals (Sweden)

Z.Khamverdi

2016-11-01

Full Text Available Introduction: Th characteristics of a suitable restoration material is having acceptable mechanical properties, protecting teeth against decay and ease of use in clinics. Diet can affct properties of restorative materials in the mouth. Since amongst important properties of composite restorations are mechanical properties such as hardness, the aim of this study was evaluation of the effct of Coca-Cola Beverages on surface hardness of a silorane based p90( and methyl methacrylate p60( composites. Methods: In this experimental study, thirty disc-shaped specimens 5 × 2 mm( of each of methyl methacrylate based Filtek p60, 3M Dental Products, USA( and a silorane based Filtek p90, 3M Dental Products, USA( composite resins were prepared, according to manufacturers' instructions. Specimens were randomly divided to four groups as follows N = 15(: G1: Filtek p90 without exposure to Coca-Cola, G2: Filtek p90 with exposure to Coca-Cola, G3: Filtek p60 without expure to Coca-Cola, G4: Filtek p60 with expure to Coca-Cola. Th specimens were exposed to regular sof drinks Coca-Cola, Khoshgovar, Tehran, Iran( at room temperature for seven days with a frequency of three times daily for 20 minutes at a time. In the remaining times of the day, they were kept in distilled water. Thn, micro hardness measurements were made for each specimen with a Vickers hardness testing machine Buehler, Lake Bluff IL, USA( under 500 g of force for 15 seconds. Data were analyzed using SPSS 18 and independent t-test at a signifiance level of 0.05. Results: Micro hardness values of four groups were G1: 68.28 ± 2.65; G2:59.56 ± 6.61; G3: 93.5 ± 2.38; and G4:86.76 ± 5.47, respectively. Th results of this study showed that Coca-Cola reduces the surface hardness of the two composite materials P > 0.05(. Conclusions: Th results showed the hardness of both Filtek p90 and Filtek p60 composite signifiantly decreases with Coca-Cola but the reduction was equal.

Study of microcracks morphology produced by Vickers indentation on AISI 1045 borided steels

International Nuclear Information System (INIS)

Campos, I.; Ramirez, G.; VillaVelazquez, C.; Figueroa, U.; Rodriguez, G.

2008-01-01

In this work, we analyzed the roughness morphology of indentation microcracks produced by the Vickers microindentation in the iron boride Fe 2 B. Using the paste boriding process, the boride layers were formed at the surface of AISI 1045 steels. The diffusion processes were carried out with 5 mm of boron paste thickness over the substrate surface at three different temperatures (1193, 1223 and 1273 K) with two different time exposures. The indentations in each Fe 2 B layer were made using a constant load of 200 g at four different distances from the surface. The fracture behavior of the Fe 2 B borided phase is found to be brittle in nature. The profiles of microcracks formed at the corners of the indentations were obtained using the scanning electronic microscopy and were analyzed within the framework of fractal geometry. We found that all indentation microcracks display a self-affine invariance characterized by the same roughness (Hurst) exponent H = 0.8 ± 0.1. The effect of the self-affine roughness of indentation microcracks on the measured fracture toughness is discussed within the framework of the mechanics of self-affine cracks. It is pointed out that the arrest of indentation microcracks is controlled by the fractal fracture toughness, which for the Fe 2 B borided phase is found to be K fc = 0.42 ± 0.02 MPa m 0.75 at all distances from the surface

Al–Mn coating electrodeposited from ionic liquid on NdFeB magnet with high hardness and corrosion resistance

Energy Technology Data Exchange (ETDEWEB)

Ding, Jingjing; Xu, Bajin; Ling, Guoping, E-mail: linggp@zju.edu.cn

2014-06-01

Al–Mn coatings were electrodeposited on sintered NdFeB permanent magnet in MnCl{sub 2}–AlCl{sub 3}–1-ethyl-3-methylim-idazolium chloride (MnCl{sub 2}–AlCl{sub 3}–EMIC) ionic liquid at room temperature. The coatings were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The adhesion strength of the coating on NdFeB substrate was evaluated by thermal shock and scratch test. The hardness and corrosion behavior of Al–Mn coating were measured by a Knoop microhardness tester, immersion test and neutral salt spray test respectively. The results showed that the amorphous structure of the deposits was obtained at the current density of 6 mA/cm{sup 2}, while higher current densities resulted in a mixed structure of amorphous and crystalline. The Al–Mn coating showed excellent adhesion strength on NdFeB substrate with the thermal shock test over 30 cycles and L{sub c} > 80 N. The hardness of Al–Mn coating was up to 5.4 GPa. The amorphous Al–Mn coating showed an anodic sacrificial protection with a low corrosion rate for NdFeB. Meanwhile, the magnetic properties measured by an AMT-4 magnetic measurement device showed that Al–Mn coating did not deteriorate the magnetic property of NdFeB.

Al–Mn coating electrodeposited from ionic liquid on NdFeB magnet with high hardness and corrosion resistance

International Nuclear Information System (INIS)

Ding, Jingjing; Xu, Bajin; Ling, Guoping

2014-01-01

Al–Mn coatings were electrodeposited on sintered NdFeB permanent magnet in MnCl 2 –AlCl 3 –1-ethyl-3-methylim-idazolium chloride (MnCl 2 –AlCl 3 –EMIC) ionic liquid at room temperature. The coatings were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The adhesion strength of the coating on NdFeB substrate was evaluated by thermal shock and scratch test. The hardness and corrosion behavior of Al–Mn coating were measured by a Knoop microhardness tester, immersion test and neutral salt spray test respectively. The results showed that the amorphous structure of the deposits was obtained at the current density of 6 mA/cm 2 , while higher current densities resulted in a mixed structure of amorphous and crystalline. The Al–Mn coating showed excellent adhesion strength on NdFeB substrate with the thermal shock test over 30 cycles and L c > 80 N. The hardness of Al–Mn coating was up to 5.4 GPa. The amorphous Al–Mn coating showed an anodic sacrificial protection with a low corrosion rate for NdFeB. Meanwhile, the magnetic properties measured by an AMT-4 magnetic measurement device showed that Al–Mn coating did not deteriorate the magnetic property of NdFeB.

Novel in situ mechanical testers to enable integrated metal surface micro-machines.

Energy Technology Data Exchange (ETDEWEB)

Follstaedt, David Martin; de Boer, Maarten Pieter; Kotula, Paul Gabriel; Hearne, Sean Joseph; Foiles, Stephen Martin; Buchheit, Thomas Edward; Dyck, Christopher William

2005-10-01

The ability to integrate metal and semiconductor micro-systems to perform highly complex functions, such as RF-MEMS, will depend on developing freestanding metal structures that offer improved conductivity, reflectivity, and mechanical properties. Three issues have prevented the proliferation of these systems: (1) warpage of active components due to through-thickness stress gradients, (2) limited component lifetimes due to fatigue, and (3) low yield strength. To address these issues, we focus on developing and implementing techniques to enable the direct study of the stress and microstructural evolution during electrodeposition and mechanical loading. The study of stress during electrodeposition of metal thin films is being accomplished by integrating a multi-beam optical stress sensor into an electrodeposition chamber. By coupling the in-situ stress information with ex-situ microstructural analysis, a scientific understanding of the sources of stress during electrodeposition will be obtained. These results are providing a foundation upon which to develop a stress-gradient-free thin film directly applicable to the production of freestanding metal structures. The issues of fatigue and yield strength are being addressed by developing novel surface micromachined tensile and bend testers, by interferometry, and by TEM analysis. The MEMS tensile tester has a ''Bosch'' etched hole to allow for direct viewing of the microstructure in a TEM before, during, and after loading. This approach allows for the quantitative measurements of stress-strain relations while imaging dislocation motion, and determination of fracture nucleation in samples with well-known fatigue/strain histories. This technique facilitates the determination of the limits for classical deformation mechanisms and helps to formulate a new understanding of the mechanical response as the grain sizes are refined to a nanometer scale. Together, these studies will result in a science

Influence of Sn content on microstructural and mechanical properties of centrifugal cast Ti-Nb-Sn biomedical alloys; Efeitos da adicao de Sn na evolucao microestrutural e em propriedades mecanicas de ligas Ti-Nb-Sn biomedicas fundidas por centrifugacao

Energy Technology Data Exchange (ETDEWEB)

Lopes, E.S.N.; Contieri, R.J.; Caram, R., E-mail: ederlopes@fem.unicamp.b [Universidade Estadual de Campinas (DEMA/FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Materiais; Moraes, P.E.L. [FATEC Artur Azevedo, Mogi Mirim, SP (Brazil); Costa, A.M.S. [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia. Dept. de Engenharia de Materiais

2010-07-01

The arc voltaic centrifugal casting is an interesting alternative in terms of economic and technological development in the production of components based on materials with high reactivity and high melting point, such as titanium alloys. In this work, Ti-30Nb (wt. %) with additions of Sn (2, 4, 6, 8 and 10 wt. %) were formed by casting process. Characterization of the samples included optical microscopy, scanning electron microscopy, X-ray diffraction, Vickers hardness and elastic modulus measures by acoustic techniques. It was observed that the microstructure of the samples investigated is composed by dendritic structures, with clear segregation of alloying elements. The Vickers hardness and the elastic modulus decreased with the addition of Sn. The results show that the mechanical behavior of Ti-Nb alloys can be controlled within certain limits, by adding Sn. (author)

Influence of Sn content on microstructural and mechanical properties of centrifugal cast Ti-Nb-Sn biomedical alloys

International Nuclear Information System (INIS)

Lopes, E.S.N.; Contieri, R.J.; Caram, R.; Costa, A.M.S.

2010-01-01

The arc voltaic centrifugal casting is an interesting alternative in terms of economic and technological development in the production of components based on materials with high reactivity and high melting point, such as titanium alloys. In this work, Ti-30Nb (wt. %) with additions of Sn (2, 4, 6, 8 and 10 wt. %) were formed by casting process. Characterization of the samples included optical microscopy, scanning electron microscopy, X-ray diffraction, Vickers hardness and elastic modulus measures by acoustic techniques. It was observed that the microstructure of the samples investigated is composed by dendritic structures, with clear segregation of alloying elements. The Vickers hardness and the elastic modulus decreased with the addition of Sn. The results show that the mechanical behavior of Ti-Nb alloys can be controlled within certain limits, by adding Sn. (author)

Evaluation of Degradation of Isothermally Aged Plasma-Sprayed Thermal Barrier Coating

Energy Technology Data Exchange (ETDEWEB)

Koo, Jae Mean; Seok, Chang Sung; Kang, Min Sung; Kim, Dae Jin [Sungkyunkwan University, Seoul (Korea, Republic of); Lee, Dong Hoon [HYUNDAI STEEL CO., Incheon (Korea, Republic of); Kim, Mun Young [KPS Gas Turbine Technology Service Center, Seongnam (Korea, Republic of)

2010-04-15

The thermal barrier coating of a gas turbine blade was degraded by isothermal heating in a furnace and by varying the exposure time and temperature. Then, a micro-Vickers hardness test was conducted on the cross section of the bond coat and Ni-based superalloy substrate. Further, the thickness of TGO(Thermally Grown Oxide) was measured by using an image analyzer, and the changes in the microstructure and element contents in the coating were analyzed by using an optical microscope and by performing SEM-EDX analysis. No significant change was observed in the Vickers hardness of the bond coat when the coated specimen was degraded at a high temperature: delamination was observed between the top coat and the bond coat when the coating was degraded for 50 h at a temperature 1,151 .deg. C.

Comparison of Knoop and Vickers surface microhardness and transverse microradiography for the study of early caries lesion formation in human and bovine enamel.

Science.gov (United States)

Lippert, F; Lynch, R J M

2014-07-01

The aims of the present laboratory study were twofold: a) to investigate the suitability of Knoop and Vickers surface microhardness (SMH) in comparison to transverse microradiography (TMR) to investigate early enamel caries lesion formation; b) to compare the kinetics of caries lesion initiation and progression between human and bovine enamel. Specimens (90×bovine and 90×human enamel) were divided into six groups (demineralization times of 8/16/24/32/40/48h) of 15 per enamel type and demineralized using a partially saturated lactic acid solution. SMH was measured before and after demineralization and changes in indentation length (ΔIL) calculated. Lesions were characterized using TMR. Data were analyzed (two-way ANOVA) and Pearson correlation coefficients calculated. ΔIL increased with increasing demineralization times but plateaued after 40h, whereas lesion depth (L) and integrated mineral loss (ΔZ) increased almost linearly throughout. No differences between Knoop and Vickers SMH in their ability to measure enamel demineralization were observed as both correlated strongly. Overall, ΔIL correlated strongly with ΔZ and L but only moderately with the degree of surface zone mineralization, whereas ΔZ and L correlated strongly. Bovine demineralized faster than human enamel (all techniques). Lesions in bovine formed faster than in human enamel, although the resulting lesions were almost indistinguishable in their mineral distribution characteristics. Early caries lesion demineralization can be sufficiently studied by SMH, but its limitations on the assessment of the mineral status of more demineralized lesions must be considered. Ideally, complementary techniques to assess changes in both physical and chemical lesion characteristics would be employed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Processing and characterization of laser sintered hybrid B4C/cBN reinforced Ti-based metal matrix composite

Science.gov (United States)

Gupta, Ankit; Hussain, Manowar; Misra, Saurav; Das, Alok Kumar; Mandal, Amitava

2018-06-01

The purpose of this study is to make a boron carbide (B4C) and cubic boron nitride (cBN) reinforced Ti6Al4V metal matrix composites (MMC's) by direct metal laser sintering (DMLS) technique using the continuous wave (CW) SPI fiber laser and to check the feasibility of the formation of three dimensional objects by this process. For this study, the process parameters like laser power density (3.528-5.172 W/cm2 (×104), scanning speed (3500-4500 mm/min), composition of the reinforced materials B4C (5-25% by volume) and cBN (3% by volume) were taken as input variables and hatching gap (0.2 mm), spot diameter (0.4 mm), layer thickness (0.4 mm) were taken as constant. It was analyzed that surface characteristic, density and the mechanical properties of sintered samples were greatly influenced by varying the input process parameters. Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX) and X-Ray diffraction (XRD) were performed for microstructural analysis, elemental analysis, and recognition of intermetallic compounds respectively. Mechanical properties like micro-hardness & wear rate were examined by Vickers micro-hardness tester & pin on disc arrangement respectively. From hardness tests, it was observed that hardness property of the sintered specimens was increased as compared to the parent material. The XRD results show that there is a good affinity between Ti6Al4V-B4C-cBN to produce various intermetallic compounds which themselves enhance the mechanical properties of the samples. From FESEM analysis, we can conclude that there is a uniform distribution of reinforcements in the titanium alloy matrix. Furthermore, the coefficient of friction (COF) was characterized by the irregular pattern and it tends to decrease with an increase in the volume % of reinforcement. The results obtained in this work may be useful in preparing the MMC's with improved mechanical properties and overall characteristics.

A new approach to the estimation of surface free energy based on Vickers microhardness data

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available A relation between surface free energy (σMHV and Meyer’s lines cut-values has been established using Vickers microhardness (MHV method and empirical physical laws. This relation allows the calculation of σMHV only from MHV data. The parameters required are Meyer’s lines cut-values and the mean value of diagonal length of the impression at different loads applied (drealmean. Our study of 12 samples of ultra high molecular weight polyethylene (PE-UHMW showed that the new approach is applicable when the slope value of Meyer’s lines equals 2 (i.e. n = 2. A γ-60Co source was used for the irradiation of 11 samples (one of the samples investigated is un-irradiated at room temperature in air. Doses of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000 and 1500 kGy were applied. The values of σMHV obtained are in a good agreement with the literature. The dependence of σMHV on the dose applied strictly corresponds to the radiation effects theory. MHV was measured at seven different loads – 0.0123, 0.0245, 0.049, 0.098, 0.196, 0.392, 0.785 N at a loading time of 30 s.

Study on Plastic Deformation Characteristics of Shot Peening of Ni-Based Superalloy GH4079

Science.gov (United States)

Zhong, L. Q.; Liang, Y. L.; Hu, H.

2017-09-01

In this paper, the X-ray stress diffractometer, surface roughness tester, field emission scanning electron microscope(SEM), dynamic ultra-small microhardness tester were used to measure the surface residual stress and roughness, topography and surface hardness changes of GH4079 superalloy, which was processed by metallographic grinding, turning, metallographic grinding +shot peening and turning + shot peening. Analysized the effects of shot peening parameters on shot peening plastic deformation features; and the effects of the surface state before shot peening on shot peening plastic deformation characteristics. Results show that: the surface residual compressive stress, surface roughness and surface hardness of GH4079 superalloy were increased by shot peening, in addition, the increment of the surface residual compressive stress, surface roughness and surface hardness induced by shot peening increased with increasing shot peening intensity, shot peening time, shot peening pressure and shot hardness, but harden layer depth was not affected considerably. The more plastic deformation degree of before shot peening surface state, the less increment of the surface residual compressive stress, surface roughness and surface hardness induced by shot peening.

An investigation of the composition of gases sampled by formation testers during drilling and well development

Energy Technology Data Exchange (ETDEWEB)

Kamkina, L.S.; Snezhko, M.P.

1983-01-01

The experience of studying samples taken by formation testers during the drilling and development of wells that penetrate Foraminifera, Cretaceous and Jurassic deposits at the fields of the Chechen-Ingush Autonomous Soviet Socialist Republic is correlated. The compositions of gases taken from oil bearing, water bearing and gas bearing deposits in exploratory and operating wells are compared. Recommendations are given for determining (estimating) the phase state of hydrocarbons in the cross section based on results from an investigation of the composition of gas taken during the drilling process. A corresponding interpretation method is proposed.

Explosive component acceptance tester using laser interferometer technology

Science.gov (United States)

Wickstrom, Richard D.; Tarbell, William W.

1993-01-01

Acceptance testing of explosive components requires a reliable and simple to use testing method that can discern less than optimal performance. For hot-wire detonators, traditional techniques use dent blocks or photographic diagnostic methods. More complicated approaches are avoided because of their inherent problems with setup and maintenance. A recently developed tester is based on using a laser interferometer to measure the velocity of flying plates accelerated by explosively actuated detonators. Unlike ordinary interferometers that monitor displacement of the test article, this device measures velocity directly and is commonly used with non-spectral surfaces. Most often referred to as the VISAR technique (Velocity Interferometer System for Any Reflecting Surface), it has become the most widely-accepted choice for accurate measurement of velocity in the range greater than 1 mm/micro-s. Traditional VISAR devices require extensive setup and adjustment and therefore are unacceptable in a production-testing environment. This paper describes a new VISAR approach which requires virtually no adjustments, yet provides data with accuracy comparable to the more complicated systems. The device, termed the Fixed-Cavity VISAR, is currently being developed to serve as a product verification tool for hot-wire detonators and slappers. An extensive data acquisition and analysis computer code was also created to automate the manipulation of raw data into final results.

Behavioral intention to take up different types of HIV testing among men who have sex with men who were never-testers in Hong Kong.

Science.gov (United States)

Wang, Zixin; Lau, Joseph T F; She, Rui; Ip, Mary; Jiang, Hui; Ho, Shara P Y; Yang, XueYing

2018-01-01

Human immunodeficiency virus (HIV) testing is an important global prevention strategy but underutilized by local men who have sex with men (MSM). This study investigated the prevalence of behavioral intention to take up HIV testing (specific or any type), in the next six months among MSM who had not been tested for HIV in the last three years (never-testers) in Hong Kong. The data was based on 141 never-testers of 430 MSM who completed the anonymous baseline telephone survey of an ongoing randomized controlled trial from January 2015 to August 2015. Only 17.7% of them showed strong intention to take up any type of HIV testing in the next six months. Adjusted analysis showed that perceived benefit of HIV testing (adjusted odds ratio [AOR]: 1.29, 95% confidence interval [CI]: 1.01, 1.66), perceived psychological barriers of HIV testing (AOR: 0.85, 95%CI: 0.73, 1.00), and perceived self-efficacy in taking up HIV testing (AOR: 1.28, 95%CI: 1.07, 1.52) were significantly associated with behavioral intention to take up any HIV testing. Perceived cue to action from non-governmental organization staff was positively associated with a marginal p-value of 0.077 (AOR: 2.37, 95%CI: 0.97, 5.77). It is warranted to strengthen perceived benefit, remove psychological barriers, and increase perceived self-efficacy related to HIV testing. Innovative and effective health promotions are greatly needed to increase HIV testing coverage among never-testers.

Room Temperature Elastic Moduli and Vickers Hardness of Hot-Pressed LLZO Cubic Garnet

Science.gov (United States)

2012-01-01

4140-steel [29] as well as composites such as Al/Al2O3 [30] and Ni– YSZ cermets [27]. The RUS apparatus used in this study consists of a computer...Microstructure and lattice parameter of LLZO specimens In this study , the LLZO microstructure was observed on a (i) fracture surface of LLZO-01 (Fig. 1a) and... study are consistent with the trend (Eq. 2) of a power law decrease in mechanical properties with increasing lattice parameter observed for other garnet

Suitability of Torrent Permeability Tester to measure air-permeability of covercrete

Energy Technology Data Exchange (ETDEWEB)

Andrade, C.; Gonzales-Gasca, C. [Institute of Construction Sciences ' Eduardo Torroja' , Madrid (Spain); Torrent, R. [Portland Cement Institute, (Argentina)

2000-07-01

Suitability of the Torrent Permeability Tester (TPT) to measure the permeability of covercrete to air, both in the laboratory and the field, is investigated, and test results obtained in laboratory studies are discussed. The tests performed included the determination of air permeability (TPT method), oxygen permeability (Cembureau method) and capillary suction, rapid chloride permeability test (ASTM C 1202), as well as a one-year carbonation depth test. Concrete specimens of various compositions and curing regimes were used in the tests; the gas-permeability tests were repeated on the same specimens after 28 days, than again at 6 months and 12 months. Test results confirmed the suitability of the TPT as a useful tool in the characterization of the quality the of concrete cover. It was found to be sensitive to changes in concrete quality; repeatable for sensitive properties such as gas permeability ; also, it was found to correlate well with other durability-related properties. 10 refs., 8 tabs., 8 figs.

Effect of a self-adhesive coating on the load-bearing capacity of tooth-coloured restorative materials.

Science.gov (United States)

Bagheri, R; Palamara, Jea; Mese, A; Manton, D J

2017-03-01

The aim of this study was to compare the flexural strength and Vickers hardness of tooth-coloured restorative materials with and without applying a self-adhesive coating for up to 6 months. Specimens were prepared from three resin composites (RC), two resin-modified glass-ionomer cements (RM-GIC) and two conventional glass-ionomer cements (CGIC). All materials were tested both with and without applying G-Coat Plus (GCP). Specimens were conditioned in 37 °C distilled deionized water for 24 h, and 1, 3 and 6 months. The specimens were strength tested using a four-point bend test jig in a universal testing machine. The broken specimen's halves were used for Vickers hardness testing. Representative specimens were examined under an environmental scanning electron microscope. Data analysis showed that regardless of time and materials, generally the surface coating was associated with a significant increase in the flexural strength of the materials. Applying the GCP decreased the hardness of almost all materials significantly (P < 0.05) and effect of time intervals on hardness was material dependent. The load-bearing capacity of the restorative materials was affected by applying self-adhesive coating and ageing. The CGIC had significantly higher hardness but lower flexural strength than the RM-GIC and RC. © 2016 Australian Dental Association.

Weibull modulus of hardness, bend strength, and tensile strength of Ni−Ta−Co−X metallic glass ribbons

Energy Technology Data Exchange (ETDEWEB)

Neilson, Henry J., E-mail: hjn2@case.edu [Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH (United States); Petersen, Alex S.; Cheung, Andrew M.; Poon, S. Joseph; Shiflet, Gary J. [University of Virginia, 395 McCormick Road, P.O. Box 400745, Charlottesville, VA 22904 (United States); Widom, Mike [Carnegie Mellon University, 5000 Forbes Avenue, Wean Hall 3325, Pittsburgh, PA 15213 (United States); Lewandowski, John J. [Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH (United States)

2015-05-14

In this study, the variations in mechanical properties of Ni−Co−Ta-based metallic glasses have been analyzed. Three different chemistries of metallic glass ribbons were analyzed: Ni{sub 45}Ta{sub 35}Co{sub 20}, Ni{sub 40}Ta{sub 35}Co{sub 20}Nb{sub 5}, and Ni{sub 30}Ta{sub 35}Co{sub 30}Nb{sub 5}. These alloys possess very high density (approximately 12.5 g/cm{sup 3}) and very high strength (e.g. >3 GPa). Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) were used to characterize the amorphicity of the ribbons. Mechanical properties were measured via a combination of Vickers hardness, bending strength, and tensile strength for each chemistry. At least 50 tests were conducted for each chemistry and each test technique in order to quantify the variability of properties using both 2- and 3-parameter Weibull statistics. The variability in properties and their source(s) were compared to that of other engineering materials, while the nature of deformation via shear bands as well as fracture surface features have been determined using scanning electron microscopy (SEM). Toughness, the role of defects, and volume effects are also discussed.

Mechanical behavior of mullite-zirconia composites

Directory of Open Access Journals (Sweden)

Sahnoune F.

2010-06-01

Full Text Available In this work, mechanical properties of mullite–zirconia composites synthesised through reaction sintering of Algerian kaolin, α-Al2O3, and ZrO2 were characterized. Phases present and their transformations were characterized using x-ray diffraction. Hardness H and fracture toughness KIC were measured by Vickers indentation using a Zwick microhardness tester. The flexural strength was measured through three point bending test using an Instron Universal Testing Machine. It was found that the increase of ZrO2 content (from 0 to 32wt.% decreased the microhardness of the composites from 14 to 10.8 GPa. However, the increase of ZrO2 content (from 0 to 24wt.% increased the flexural strength of the composites from 142 to 390 MPa then decreased it with further increase of ZrO2 content. Also, the fracture toughness increased from 1.8 to 2.9 MPa.m1/2 with the increase of ZrO2 content from 0 to 32 wt.%; and the rate of the increase decreased at higher fractions of ZrO2 content. The average linear coefficient of thermal expansion (within the range 50 to 1450°C for samples containing 0 and 16 wt.% ZrO2 sintered at 1600°C for 2 hours was 4.7 x10-6 K-1 and 5.2 x 10-6 K-1 respectively.

Synthesis, growth and characterization of o-phenylinediaminium benzilate: An SHG material with high laser damage threshold for NLO applications

Science.gov (United States)

Rajkumar, M.; Chandramohan, A.

2017-02-01

An organic molecular charge transfer complex salt, o-phenylenediaminium benzilate was synthesized and single crystals grown by slow solvent evaporation solution growth technique in methanol at ambient temperature. The grown crystal was subjected to Single crystal XRD analysis to establish the molecular structure. The molecular structure was further confirmed by 1H and 13C NMR spectral studies. The formation of the charge transfer complex salt was confirmed by UV-VIS spectroscopic technique. To identify the optical transmittance window and lower wavelength cut-off, the crystal was subjected to UV-Vis-NIR transmission spectral studies. The presence of various functional groups in the salt crystal was confirmed by FT-IR spectroscopic technique. Photoluminescence study was carried out to explore its efficiency towards device fabrications. The TG and DTA thermal analyses were simultaneously carried out to establish the thermal stability of the crystal. The dielectric studies of the grown crystal were executed at different temperatures as a function of frequency to investigate its electrical properties. The SHG efficiency of the crystal was determined using the modified Kurtz and Perry powder technique and its value was found to be 1.98 times that of the KDP crystal. Laser damage threshold value was measured using Nd:YAG laser. The mechanical stability of the title crystal was established employing Vickers micro hardness tester.

The Development and Application of Simulative Insulation Resistance Tester

Science.gov (United States)

Jia, Yan; Chai, Ziqi; Wang, Bo; Ma, Hao

2018-02-01

The insulation state determines the performance and insulation life of electrical equipment, so it has to be judged in a timely and accurate manner. Insulation resistance test, as the simplest and most basic test of high voltage electric tests, can measure the insulation resistance and absorption ratio which are effective criterion of part or whole damp or dirty, breakdown, severe overheating aging and other insulation defects. It means that the electrical test personnel need to be familiar with the principle of insulation resistance test, and able to operate the insulation resistance tester correctly. At present, like the insulation resistance test, most of electrical tests are trained by physical devices with the real high voltage. Although this allows the students to truly experience the test process and notes on security, it also has certain limitations in terms of safety and test efficiency, especially for a large number of new staves needing induction training every year. This paper presents a new kind of electrical test training system based on the simulative device of dielectric loss measurement and simulative electrical testing devices. It can not only overcome the defects of current training methods, but also provide other advantages in economical efficiency and scalability. That makes it possible for the system to be allied in widespread.

Anti-scratch AlMgB14 Gorilla® Glass coating

Science.gov (United States)

Putrolaynen, V. V.; Grishin, A. M.; Rigoev, I. V.

2017-10-01

Hard aluminum-magnesium boride (BAM) films were fabricated onto Corning® Gorilla® Glass by radio-frequency magnetron sputtering of a single stoichiometric AlMgB14 target. BAM films exhibit a Vickers hardness from 10 to 30 GPa and a Young's modulus from 80 to 160 GPa depending on applied loading forces. Deposited hard coating increases the critical load at which glass substrate cracks. The adhesion energy of BAM films on Gorilla® Glass is 6.4 J/m2.

Effect of Temperature, Pressure and Equivalence Ratio on Ignition Delay in Ignition Quality Tester (IQT): Diesel,n-Heptane, andiso-Octane Fuels under Low Temperature Conditions

KAUST Repository

Yang, Seung Yeon; Naser, Nimal; Chung, Suk-Ho; Cha, Junepyo

2015-01-01

-octane in relatively low temperature conditions to simulate unsteady spray ignition behavior. A KAUST Research ignition quality tester (KR-IQT) was utilized, which has a feature of varying temperature, pressure and equivalence ratio using a variable displacement fuel

The effects of vanadium on the microstructure and wear resistance of centrifugally cast Ni-hard rolls

International Nuclear Information System (INIS)

Kang, Minwoo; Suh, Yongchan; Oh, Yong-Jun; Lee, Young-Kook

2014-01-01

Highlights: • V addition changed the pro-eutectic phase from austenite to vermicular (V,Nb)C. • Pro-eutectic (V,Nb)C particles were segregated to the inner part of the roll. • Wear loss was inversely proportional to MC fraction under the same graphite fraction. • Cementite particles acted as the initiation site and propagation path of cracks. • High-temperature wear sequence of centrifugally cast Ni-hard rolls was suggested. - Abstract: The effects of V on the microstructure and wear resistance of centrifugally cast Ni-hard rolls are investigated under a constant fraction of graphite using electron microscopes and a revolving disk-type high-temperature wear tester. The volume fraction of (V,Nb)C particles was increased at the expense of the volume fraction of cementite with an increase in the V concentration. However, the volume fraction of graphite was held nearly constant by controlling the concentration ratio of Si and Cr. As the V concentration was higher than 3 wt.%, the pro-eutectic phase was changed from austenite to (V,Nb)C carbide. The pro-eutectic vermicular (V,Nb)C particles were segregated to the inner part of the roll during centrifugal casting. The wear resistance was improved with an addition of V due to the high volume fractions of the coarse eutectic and pro-eutectic (V,Nb)C particles and the precipitation hardening of fine (V,Nb)C particles in the martensitic matrix. The worn surface showed that cementite particles acted as the initiation site and propagation route of cracks

Crack-resistant Al2O3–SiO2 glasses

Science.gov (United States)

Rosales-Sosa, Gustavo A.; Masuno, Atsunobu; Higo, Yuji; Inoue, Hiroyuki

2016-01-01

Obtaining “hard” and “crack-resistant” glasses have always been of great important in glass science and glass technology. However, in most commercial glasses both properties are not compatible. In this work, colorless and transparent xAl2O3–(100–x)SiO2 glasses (30 ≤ x ≤ 60) were fabricated by the aerodynamic levitation technique. The elastic moduli and Vickers hardness monotonically increased with an increase in the atomic packing density as the Al2O3 content increased. Although a higher atomic packing density generally enhances crack formation in conventional oxide glasses, the indentation cracking resistance increased by approximately seven times with an increase in atomic packing density in binary Al2O3–SiO2 glasses. In particular, the composition of 60Al2O3•40SiO2 glass, which is identical to that of mullite, has extraordinary high cracking resistance with high elastic moduli and Vickers hardness. The results indicate that there exist aluminosilicate compositions that can produce hard and damage-tolerant glasses. PMID:27053006

Tungsten tetraboride, an inexpensive superhard material

Science.gov (United States)

Mohammadi, Reza; Lech, Andrew T.; Xie, Miao; Weaver, Beth E.; Yeung, Michael T.; Tolbert, Sarah H.; Kaner, Richard B.

2011-01-01

Tungsten tetraboride (WB4) is an interesting candidate as a less expensive member of the growing group of superhard transition metal borides. WB4 was successfully synthesized by arc melting from the elements. Characterization using powder X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) indicates that the as-synthesized material is phase pure. The zero-pressure bulk modulus, as measured by high-pressure X-ray diffraction for WB4, is 339 GPa. Mechanical testing using microindentation gives a Vickers hardness of 43.3 ± 2.9 GPa under an applied load of 0.49 N. Various ratios of rhenium were added to WB4 in an attempt to increase hardness. With the addition of 1 at.% Re, the Vickers hardness increased to approximately 50 GPa at 0.49 N. Powders of tungsten tetraboride with and without 1 at.% Re addition are thermally stable up to approximately 400 °C in air as measured by thermal gravimetric analysis. PMID:21690363

Comparative assessment of the microhardness and plastic degradation mechanism of deposited modulated coatings on mild steel

Science.gov (United States)

Fayomi, O. S. I.; Anawe, P. A. L.; Inegbenebor, A. O.; Udoye, N. E.

2018-05-01

Zinc based coatings modified with aluminium and tin inclusions were electrodeposited in chloride zinc sulfate electrolytes containing a metallic powder of titanium. It was found that presence of these particulates is suitable to obtain ZnAlSn-Ti composites coating that could help increase the microhardnesss characteristics and wear properties. The hardness and wear properties of the deposited coatings were examined with diamond base micro-hardness tester and CETR reciprocating sliding tester respectively. The structural properties were examined with the help of scanning electron microscope. It was observed that structural coating surface impact on the hardness propagation with increases from 33.4 to 299 kgf mm-2 (HVN40), and shows a considerably higher wear resistance from 2.351g/min to 0.002g/min. It is obvious that plastic deformation of the working steel structure is dependent on protective coating and the concentration of the individual particulate.

Influences of Light-emitting Diode Illumination Bleaching Technique on Nanohardness of Computer-aided Design and Computer-aided Manufacturing Ceramic Restorative Materials.

Science.gov (United States)

Juntavee, Niwut; Juntavee, Apa; Saensutthawijit, Phuwiwat

2018-02-01

This study evaluated the effect of light-emitting diode (LED) illumination bleaching technique on the surface nanohardness of various computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic materials. Twenty disk-shaped samples (width, length, and thickness = 10, 15, and 2 mm) were prepared from each of the ceramic materials for CAD/CAM, including Lava™ Ultimate (L V ), Vita Enamic® (E n ) IPS e.max® CAD (M e ), inCoris® TZI (I C ), and Prettau® zirconia (P r ). The samples from each type of ceramic were randomly divided into two groups based on the different bleaching techniques to be used on them, using 35% hydrogen peroxide with and without LED illumination. The ceramic disk samples were bleached according to the manufacturer's instruction. Surface hardness test was performed before and after bleaching using nanohardness tester with a Berkovich diamond indenter. The respective Vickers hardness number upon no bleaching and bleaching without or with LED illumination [mean ± standard deviation (SD)] for each type of ceramic were as follows: 102.52 ± 2.09, 101.04 ± 1.18, and 98.17 ± 1.15 for L V groups; 274.96 ± 5.41, 271.29 ± 5.94, and 268.20 ± 7.02 for E n groups; 640.74 ± 31.02, 631.70 ± 22.38, and 582.32 ± 33.88 for M e groups; 1,442.09 ± 35.07, 1,431.32 ± 28.80, and 1,336.51 ± 34.03 for I C groups; and 1,383.82 ± 33.87, 1,343.51 ± 38.75, and 1,295.96 ± 31.29 for P r groups. The results indicated surface hardness reduction following the bleaching procedure of varying degrees for different ceramic materials. Analysis of variance (ANOVA) revealed a significant reduction in surface hardness due to the effect of bleaching technique, ceramic material, and the interaction between bleaching technique and ceramic material (p LED illumination exhibited more reduction in surface hardness of dental ceramic than what was observed without LED illumination. Clinicians should consider protection of the existing restoration while bleaching.

Structure and mechanical properties of Al-3Fe rapidly solidified alloy

International Nuclear Information System (INIS)

Karakoese, Ercan; Keskin, Mustafa

2011-01-01

The Al based Al-3 wt%Fe alloy was prepared by conventionally casting (ingot) and further processed the melt-spinning technique and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS), differential scanning calorimetry (DSC) and the Vickers microhardness tester. The rapidly solidified (RS) binary alloys were composed of supersaturated α-Al solid solution and finely dispersed intermetallic phases. Experimental results showed that the mechanical properties of RS alloys were enhanced, which can be attributed to significant changes in the microstructure. The dependence of microhardness H V on the solidification rate (V) was analysed. These results showed that with the increasing values of V, the values of H V increased.

Microstructure and thermal stability of nickel layers electrodeposited from an additive-free sulphamate-based electrolyte

DEFF Research Database (Denmark)

Rasmussen, Anette Alsted; Møller, Per; Somers, Marcel A. J.

2006-01-01

and scanning electron microscopy and X-ray diffraction; the Vickers hardness was measured in cross sections. The present is meant as a reference for forthcoming articles on the investigation of various strengthening mechanisms on the microstructure, hardness and thermal stability of Ni (alloys) electrodeposits.......The influences of the current density and the temperature on the microstructure and hardness of Ni layers electrodeposited from an additive-free sulphamate bath were investigated. The microstructure and thermal stability of the electrodeposits was investigated with a combination of transmission...

Perancangan Dan Pengujian Radiator Tester Skala Laboratorium Yang Terintegrasi Pengatur Putaran Mesin Dan Hembusan Angin (Regulator Wind Blower )

OpenAIRE

Suudi, Ahmad

2014-01-01

Cooling system in the engine functions as the protector of the machine by absorbing the heat. Heat engine is produced by fuel in the cylinder. The heat is deliberately created to generate energy, but it will cause excessive heat if it is left unchecked (over heating effect). In order to prevent overheating and keep the machine temperature, then it uses radiator. How effective radiator is used can be seen by using a tool called a radiator tester. Therefore, this research was Designed a Trial R...

Influence of Nitrogen Gas Flow Rate on The Microstructural and Mechanical Properties of Tin Deposited Carbon Steel Synthesized by Cae

Directory of Open Access Journals (Sweden)

A. Mubarak

2017-11-01

Full Text Available This paper reports on the preparation of titanium nitride (TiN thin films on carbon steel plates, using cathodic arc evaporation CAE PVD technique. We studied and discussed the effect of various nitrogen gas flow rates on microstructural and mechanical properties of TiN-coated carbon steel plates. The coating properties investigated in this work included the surface morphology, thickness of deposited coating, adhesion between the coating and substrate, coating composition, coating crystallography, hardness and surface characterization using a field emission scanning electron microscope (FE-SEM with energy dispersive X-ray (EDX, Xray diffraction (XRD with glazing incidence angle (GIA technique, scratch tester, hardness testing machine, surface roughness tester and atomic force microscope (AFM. SEM analyses showed that all the films had columnar and dense structures with clearly defined substrate-film interfacial layers. The hardness of TiN-coated carbon steel was noted six times more than the hardness of uncoated one. An increase in nitrogen gas flow rate showed; decrease in the formation of macro-droplets, average roughness (Ra and root-mean-square (RMS values in CAE PVD technique. During XRD-GIA studies, it was observed that by increasing the nitrogen gas flow rate, the main peak [1,1,1] shifted toward the lower angular position. Microhardness of TiN-coated carbon steel showed about six times increase in hardness than the uncoated one. Scratch tester results showed an average adhesion between the coating material and substrate. Thanks to the high resolution power could be observed that by increasing nitrogen gas flow rate there was percentage increase in the bearing ratio while percentage decrease in histogram.

Development and characterization of ceramic composites alumina-titania based reinforced with lanthanum oxide for fabrication of inert coatings for metallic tanks of the oil industry; Desenvolvimento e caracterizacao de compositos ceramicos baseados em alumina-titania reforcados com oxido de lantanio para fabricacao de revestimentos inertes em tanques metalicos da industria petrolifera

Energy Technology Data Exchange (ETDEWEB)

Bandeira, J.M.; Yadava, Y.P.; Silva, N.D.G.; Ferreira, R.A.S., E-mail: julianamb91@gmail.com, E-mail: yadava@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Centro de Tecnologia e Geociencias. Departamento de Engenharia Mecanica

2016-07-01

Crude petroleum is highly corrosive causing superficial degradation in metallic tanks used for storage and transportation of this material, which causes a serious problem in the oil industry. An alternative to solve this problem is to use some kind of coating that is inert to this kind of corrosion. Alumina and titania are interesting materials for several engineering applications because, when compared with other ceramic materials, they present superior mechanical properties, e.g. high mechanical strength, good chemical stability and high fracture toughness combined with good wear resistance and a coefficient of thermal expansion close to the iron's, which makes them fit to use in ceramic hardening process and coating. In this paper, alumina-titania ceramic composites with 5%, 10%, 15% and 20% of titania (TiO2) and reinforced with 2% of lanthanum oxide of were produced by thermo-mechanical processing and sintering techniques at 1350 deg C. In these composites, microstructure and mechanical properties were analyzed using X-ray spectroscopy, optical microscopy, scanning electron microscopy and Vickers hardness in order to evaluate their applicability. X-ray spectroscopy showed the formation of composite without the presence of other phases. Optical microscopy and scanning electron microscopy showed a homogeneous microstructure in terms of particle size and distribution. Vickers hardness test showed a gradual decrease in hardness with the addition of titania. The composite with 5% of titania and 2% of lanthanum oxide is the best choice for structural applications. The composites were submerged in crude petroleum for 30 days to study their stability in such environment. Through the analysis of X-ray spectroscopy, optical microscopy and Vickers hardness before and after the submersion in crude petroleum, it was not observed structural or microstructural degradation nether alterations in mechanical properties. This way, it was concluded that these composites have

Development and characterization of ceramic composites alumina-titania based reinforced with lanthanum oxide for fabrication of inert coatings for metallic tanks of the oil industry

International Nuclear Information System (INIS)

Bandeira, J.M.; Yadava, Y.P.; Silva, N.D.G.; Ferreira, R.A.S.

2016-01-01

Crude petroleum is highly corrosive causing superficial degradation in metallic tanks used for storage and transportation of this material, which causes a serious problem in the oil industry. An alternative to solve this problem is to use some kind of coating that is inert to this kind of corrosion. Alumina and titania are interesting materials for several engineering applications because, when compared with other ceramic materials, they present superior mechanical properties, e.g. high mechanical strength, good chemical stability and high fracture toughness combined with good wear resistance and a coefficient of thermal expansion close to the iron's, which makes them fit to use in ceramic hardening process and coating. In this paper, alumina-titania ceramic composites with 5%, 10%, 15% and 20% of titania (TiO2) and reinforced with 2% of lanthanum oxide of were produced by thermo-mechanical processing and sintering techniques at 1350 deg C. In these composites, microstructure and mechanical properties were analyzed using X-ray spectroscopy, optical microscopy, scanning electron microscopy and Vickers hardness in order to evaluate their applicability. X-ray spectroscopy showed the formation of composite without the presence of other phases. Optical microscopy and scanning electron microscopy showed a homogeneous microstructure in terms of particle size and distribution. Vickers hardness test showed a gradual decrease in hardness with the addition of titania. The composite with 5% of titania and 2% of lanthanum oxide is the best choice for structural applications. The composites were submerged in crude petroleum for 30 days to study their stability in such environment. Through the analysis of X-ray spectroscopy, optical microscopy and Vickers hardness before and after the submersion in crude petroleum, it was not observed structural or microstructural degradation nether alterations in mechanical properties. This way, it was concluded that these composites have good

Y-TZP ceramic processing from coprecipitated powders: a comparative study with three commercial dental ceramics.

Science.gov (United States)

Lazar, Dolores R R; Bottino, Marco C; Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Ussui, Valter; Bressiani, Ana H A

2008-12-01

(1) To synthesize 3mol% yttria-stabilized zirconia (3Y-TZP) powders via coprecipitation route, (2) to obtain zirconia ceramic specimens, analyze surface characteristics, and mechanical properties, and (3) to compare the processed material with three reinforced dental ceramics. A coprecipitation route was used to synthesize a 3mol% yttria-stabilized zirconia ceramic processed by uniaxial compaction and pressureless sintering. Commercially available alumina or alumina/zirconia ceramics, namely Procera AllCeram (PA), In-Ceram Zirconia Block (CAZ) and In-Ceram Zirconia (IZ) were chosen for comparison. All specimens (6mmx5mmx5mm) were polished and ultrasonically cleaned. Qualitative phase analysis was performed by XRD and apparent densities were measured on the basis of Archimedes principle. Ceramics were also characterized using SEM, TEM and EDS. The hardness measurements were made employing Vickers hardness test. Fracture toughness (K(IC)) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test (alpha=0.05). ANOVA revealed that the Vickers hardness (pceramic materials composition. It was confirmed that the PA ceramic was constituted of a rhombohedral alumina matrix, so-called alpha-alumina. Both CAZ and IZ ceramics presented tetragonal zirconia and alpha-alumina mixture of phases. The SEM/EDS analysis confirmed the presence of aluminum in PA ceramic. In the IZ and CAZ ceramics aluminum, zirconium and cerium in grains involved by a second phase containing aluminum, silicon and lanthanum were identified. PA showed significantly higher mean Vickers hardness values (H(V)) (18.4+/-0.5GPa) compared to vitreous CAZ (10.3+/-0.2GPa) and IZ (10.6+/-0.4GPa) ceramics. Experimental Y-TZP showed significantly lower results than that of the other monophased ceramic (PA) (pceramics (pceramic processing conditions led to ceramics with mechanical properties comparable to commercially available reinforced ceramic materials.

Bond-orientational analysis of hard-disk and hard-sphere structures.

Science.gov (United States)

Senthil Kumar, V; Kumaran, V

2006-05-28

We report the bond-orientational analysis results for the thermodynamic, random, and homogeneously sheared inelastic structures of hard-disks and hard-spheres. The thermodynamic structures show a sharp rise in the order across the freezing transition. The random structures show the absence of crystallization. The homogeneously sheared structures get ordered at a packing fraction higher than the thermodynamic freezing packing fraction, due to the suppression of crystal nucleation. On shear ordering, strings of close-packed hard-disks in two dimensions and close-packed layers of hard-spheres in three dimensions, oriented along the velocity direction, slide past each other. Such a flow creates a considerable amount of fourfold order in two dimensions and body-centered-tetragonal (bct) structure in three dimensions. These transitions are the flow analogs of the martensitic transformations occurring in metals due to the stresses induced by a rapid quench. In hard-disk structures, using the bond-orientational analysis we show the presence of fourfold order. In sheared inelastic hard-sphere structures, even though the global bond-orientational analysis shows that the system is highly ordered, a third-order rotational invariant analysis shows that only about 40% of the spheres have face-centered-cubic (fcc) order, even in the dense and near-elastic limits, clearly indicating the coexistence of multiple crystalline orders. When layers of close-packed spheres slide past each other, in addition to the bct structure, the hexagonal-close-packed (hcp) structure is formed due to the random stacking faults. Using the Honeycutt-Andersen pair analysis and an analysis based on the 14-faceted polyhedra having six quadrilateral and eight hexagonal faces, we show the presence of bct and hcp signatures in shear ordered inelastic hard-spheres. Thus, our analysis shows that the dense sheared inelastic hard-spheres have a mixture of fcc, bct, and hcp structures.

Ti-Mo alloys employed as biomaterials: effects of composition and aging heat treatment on microstructure and mechanical behavior.

Science.gov (United States)

Cardoso, Flavia F; Ferrandini, Peterson L; Lopes, Eder S N; Cremasco, Alessandra; Caram, Rubens

2014-04-01

The correlation between the composition, aging heat treatments, microstructural features and mechanical properties of β Ti alloys is of primary significance because it is the foundation for developing and improving new Ti alloys for orthopedic biomaterials. However, in the case of Ti-Mo alloys, this correlation is not fully described in the literature. Therefore, the purpose of this study was to experimentally investigate the effect of composition and aging heat treatments on the microstructure, Vickers hardness and elastic modulus of Ti-Mo alloys. These alloys were solution heat-treated and water-quenched, after which their response to aging heat treatments was investigated. Their microstructure, Vickers hardness and elastic modulus were evaluated, and the results allow us to conclude that stabilization of the β phase is achieved with nearly 10% Mo when a very high cooling rate is applied. Young's modulus was found to be more sensitive to phase variations than hardness. In all of the compositions, the highest hardness values were achieved by aging at 723K, which was attributed to the precipitation of α and ω phases. All of the compositions aged at 573K, 623K and 723K showed overaging within 80h. © 2013 Published by Elsevier Ltd.

Radiation annealing mechanisms of low-alloy reactor pressure vessel steels dependent on irradiation temperature and neutron fluence

International Nuclear Information System (INIS)

Pachur, D.

1982-01-01

Heat treatment after irradiation of reactor pressure vessel steels showed annealing of irradiation embrittlement. Depending on the irradiation temperature, the embrittlement started to anneal at about 220 0 C and was completely annealed at 500 0 C with 4 h of annealing time. The annealing behavior was normally measured in terms of the Vickers hardness increase produced by irradiation relative to the initial hardness as a function of the annealing temperature. Annealing results of other mechanical properties correspond to hardness results. During annealing, various recovery mechanisms occur in different temperature ranges. These are characterized by activation energies from 1.5 to 2.1 eV. The individual mechanisms were determined by the different time dependencies at various temperatures. The relative contributions of the mechanisms showed a neutron fluence dependence, with the lower activation energy mechanisms being predominant at low fluence and vice versa. In the temperature range where partial annealing of a mechanism took place during irradiation, an increase in activation energy was observed. Trend curves for the increase in transition temperature with irradiation, for the relative increase of Vickers hardness and yield strength, and for the relative decrease of Charpy-V upper shelf energy are interpreted by the behavior of different mechanisms

Microstructure evolution associated with adiabatic shear bands and shear band failure in ballistic plug formation in Ti-6Al-4V targets

International Nuclear Information System (INIS)

Murr, L.E.; Ramirez, A.C.; Gaytan, S.M.; Lopez, M.I.; Martinez, E.Y.; Hernandez, D.H.; Martinez, E.

2009-01-01

The microstructures and microstructure evolution associated with adiabatic shear band (ASB) formation in ballistic plugging in thick (2.5 cm) Ti-6Al-4V targets impacted by cylindrical, 4340 steel projectiles (2.0 cm in height) at impact velocities ranging from 633 m/s to 1027 m/s (just above the ballistic limit) were investigated by optical and transmission electron microscopy. ASB width increased from 10 μm to 21 μm as the velocity increased. ASB evolution was accompanied by the evolution of dark deformation bands composed of α' martensite platelets which increased in density with increasing impact velocity. The corresponding Vickers microindentation hardness also increased from HV 619 to HV 632 in contrast to the surrounding matrix microindentation hardness of HV 555. These deformation bands were not necessarily precursors to ASB formation. The ASB average Vickers microindentation hardness was essentially constant at HV 645, a 16% increase over the matrix. This constant microindentation hardness was characterized by a consistent DRX grain structure which varied from equiaxed, defect-free grains (∼2 μm diameter) to heavily dislocated, equiaxed grains. Cracks nucleating and propagating within the ABSs were observed to increase from 8% to 87% of the ASB length with increasing impact velocity.

Surface martensitization of Carbon steel using Arc Plasma Sintering

Science.gov (United States)

Wahyudi, Haris; Dimyati, Arbi; Sebayang, Darwin

2018-03-01

In this paper new technology of surface structure modification of steel by short plasma exposure in Arc Plasma Sintering (APS) device is presented. APS is an apparatus working based on plasma generated by DC pulsed current originally used for synthesizing materials via sintering and melting. Plasma exposure in APS was applied into the specimens for 1 and 3 seconds which generate temperature approximately about 1300-1500°C. The SUP9, pearlitic carbon steel samples were used. The hardness, hardening depth and microstructure of the specimens have been investigated by Vickers micro hardness test and Scanning Electron Microscopy (SEM) supported by Energy Dispersive X-Ray Spectroscopy (EDX). The results have showed that the mechanical property was significantly improved due to the formation of single martensitic structures as identified by SEM. The hardness of treated surface evaluated by Vickers hardness test showed significant improvement nearly three time from 190 VHN before to 524 VHN after treatment. Furthermore, EDX confirmed that the formation of martensite layer occurred without altering its composition. The APS also produced uniform hardened layer up to 250 μm. The experiment has demonstrated that arc plasma process was successfully improved the mechanical properties of steel in relatively very short time.

Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

Improving the properties of mild steel by ternary multilayer composite coating via electrodeposition route

Directory of Open Access Journals (Sweden)

O. S.I. Fayomi

2017-01-01

Full Text Available A wide range of metal-oxides exhibit fascinating properties and multiple functionalities that could address challenge of physical and mechanical deterioration of materials in service. In this study, Zn-ZrO2, Zn-SiC and Zn-ZrO2-SiC composite coating was fabricated from zinc based sulphate electrolyte at constant current density, depth of immersion, distance between anode and cathode with time of deposition. The effect of particle on the physical behaviour of the coating was examined by coating gauge tester for the coating thickness and coating texture. The mechanical properties in term of hardness and wear characteristics were examined using high diamond micro-hardness tester and three body abrasive MTR-300 testers with dry sand rubber wheel apparatus with 5 N and 15 N, respectively. The coating stability in harsh region was examined with isothermal furnace at 200 oC for 4 h. The structural behaviour was investigated using scanning electron microscope attached with energy dispersion spectroscopy (SEM/EDS. The result shows that significant improvements in wear and hardness properties are linked to the microstructural modification of the coating as a result of the embedded particulate. The strengthening behaviour was improved with about 98% of coating efficiency. The progression of the coating thickness and texture were in line with other results obtained.

Metallurgical and acoustical characterization of a hydroformed, 304 stainless steel, Caribbean-style musical pan

International Nuclear Information System (INIS)

Murr, L.E.; Gaytan, S.M.; Lopez, M.I.; Bujanda, D.E.; Martinez, E.Y.; Whitmyre, G.; Price, H.

2008-01-01

We report herein the metallurgical and acoustical characterization of hydroformed 304 stainless steel, Caribbean pans. These pans were fully tuned to chromatic tones and compared to a manufactured, low-carbon, Caribbean steel pan standard. Hydroformed platforms had a Vickers microindentation hardness of HV 345, which was reduced by annealing during pan fabrication to HV 270. Skirts welded to the hydroformed head had a microindentation hardness of HV 440. Microstructural characterization by light optical metallography and transmission electron microscopy illustrated microstructures (including grain structures) characteristic of these pan microindentation hardnesses

Comprehensive hard materials

CERN Document Server

2014-01-01

Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

A comparative evaluation of effect of modern-curing lights and curing modes on conventional and novel-resin monomers

Science.gov (United States)

Roy, Konda Karthik; Kumar, Kanumuru Pavan; John, Gijo; Sooraparaju, Sujatha Gopal; Nujella, Surya Kumari; Sowmya, Kyatham

2018-01-01

Aim: The aim of this study is to compare and to evaluate effect of curing light and curing modes on the nanohybrid composite resins with conventional Bis-GMA and novel tricyclodecane (TCD) monomers. Methodology: Two nanohybrid composites, IPS empress direct and charisma diamond were used in this study. Light-emitting diode (LED)-curing unit and quartz-tungsten-halogen (QTH)-curing unit which were operated into two different modes: continuous and soft start. Based on the composite resin, curing lights, and mode of curing used, the samples were divided into 8 groups. After polymerization, the samples were stored for 48 h in complete darkness at 37°C and 100% humidity. The Vickers hardness (VK) of the surface was determined with Vickers indenter by the application of 200 g for 15 s. Three VK readings were recorded for each sample surface both on top and bottom surfaces. For all the specimens, the three hardness values for each surface were averaged and reported as a single value. The mean VK and hardness ratio were calculated. The depth of cure was assessed based on the hardness ratio. Results: Comparison of mean hardness values and hardness ratios was done using ANOVA with post hoc Tukey's test. Conclusion: Both QTH- and LED-curing units had shown the adequate depth of cure. Soft-start-curing mode in both QTH- and LED-curing lights had effectively increased microhardness than the continuous mode of curing. TCD monomer had shown higher hardness values compared with conventional Bis-GMA-containing resin. PMID:29628651

Superhard MgB sub 2 bulk material prepared by high-pressure sintering

CERN Document Server

Ma, H A; Chen, L X; Zhu, P W; Ren, G Z; Guo, W L; Fu, X Q; Zou Guang Tian; Ren, Z A; Che, G C; Zhao, Z X

2002-01-01

Superhard MgB sub 2 bulk material with a golden metallic shine was synthesized by high-pressure sintering for 8 h at 5.5 GPa and different temperatures. Appropriate pressure and temperature conditions for synthesizing polycrystalline MgB sub 2 with high hardness were investigated. The samples were characterized by means of atomic force microscopy and x-ray diffraction. The Vickers hardness, bulk density, and electrical resistivity were measured at room temperature.

Some aspects of thick, soft nickel plating for end shields of atomic power plants

International Nuclear Information System (INIS)

Krishnaswamy, R.

1987-01-01

Thick (55 Thou) and soft (160 vickers) hardness number nickel plating over SS for RAPP end shields presented unusual problems as the thickness required was extremely large creating adhesion problems and the extremely stringent hardness conditions. A sulfamate bath with nickel anode was found suitable. The problems in thick, soft plating, the chemical and other procedures adopted to monitor the bath and the plated specimen and the other details are presented. (author). 11 refs

Multimodal Friction Ignition Tester

Science.gov (United States)

Davis, Eddie; Howard, Bill; Herald, Stephen

2009-01-01

The multimodal friction ignition tester (MFIT) is a testbed for experiments on the thermal and mechanical effects of friction on material specimens in pressurized, oxygen-rich atmospheres. In simplest terms, a test involves recording sensory data while rubbing two specimens against each other at a controlled normal force, with either a random stroke or a sinusoidal stroke having controlled amplitude and frequency. The term multimodal in the full name of the apparatus refers to a capability for imposing any combination of widely ranging values of the atmospheric pressure, atmospheric oxygen content, stroke length, stroke frequency, and normal force. The MFIT was designed especially for studying the tendency toward heating and combustion of nonmetallic composite materials and the fretting of metals subjected to dynamic (vibrational) friction forces in the presence of liquid oxygen or pressurized gaseous oxygen test conditions approximating conditions expected to be encountered in proposed composite material oxygen tanks aboard aircraft and spacecraft in flight. The MFIT includes a stainless-steel pressure vessel capable of retaining the required test atmosphere. Mounted atop the vessel is a pneumatic cylinder containing a piston for exerting the specified normal force between the two specimens. Through a shaft seal, the piston shaft extends downward into the vessel. One of the specimens is mounted on a block, denoted the pressure block, at the lower end of the piston shaft. This specimen is pressed down against the other specimen, which is mounted in a recess in another block, denoted the slip block, that can be moved horizontally but not vertically. The slip block is driven in reciprocating horizontal motion by an electrodynamic vibration exciter outside the pressure vessel. The armature of the electrodynamic exciter is connected to the slip block via a horizontal shaft that extends into the pressure vessel via a second shaft seal. The reciprocating horizontal

Hardness and stability of a carburized surface layer on AISI 316L stainless steel after irradiation in a spallation neutron environment

International Nuclear Information System (INIS)

McClintock, David A.; Hyres, James W.; Vevera, Bradley J.

2014-01-01

The inner surfaces of mercury target vessels at the Spallation Neutron Source (SNS) experience material erosion caused by proton-beam induced cavitation of the liquid mercury. One approach developed and deployed to inhibit erosion of the target vessel material was surface hardening via a proprietary low-temperature carburization treatment, called Kolsterising®, to the target surfaces most susceptible to cavitation-induced erosion. Previous testing has shown that the hardened surface produced by the Kolsterising® treatment can delay the onset of erosion and inhibit erosion once initiated. But the stability of the carbon atmosphere in the treated surface layer after radiation to doses prototypic to the SNS target was unknown. Therefore, as part of the target Post Irradiation Examination program at the SNS, optical microscopy and microhardness testing were performed on material sampled from the first and second operational SNS target vessels. Optical micrographs contained no noticeable precipitation in the super-saturated carbon layer extending into the base material and several micrographs contained evidence of a proposed mechanism for mass wastage from the vessel surface. The hardened layer was characterized using Vickers microhardness testing and results show that the shape of hardness profile of the treated layer corresponded well with known pre-irradiation hardness values, though the microhardness results show some hardening occurred during irradiation. The results suggest that the hardened surface layer produced by the Kolsterising® treatment is stable at the operational temperatures and dose levels experienced by the first and second operational SNS target modules

Computational Fluid Dynamics Simulation of Hydrodynamics and Stresses in the PhEur/USP Disintegration Tester Under Fed and Fasted Fluid Characteristics.

Science.gov (United States)

Kindgen, Sarah; Wachtel, Herbert; Abrahamsson, Bertil; Langguth, Peter

2015-09-01

Disintegration of oral solid dosage forms is a prerequisite for drug dissolution and absorption and is to a large extent dependent on the pressures and hydrodynamic conditions in the solution that the dosage form is exposed to. In this work, the hydrodynamics in the PhEur/USP disintegration tester were investigated using computational fluid dynamics (CFD). Particle image velocimetry was used to validate the CFD predictions. The CFD simulations were performed with different Newtonian and non-Newtonian fluids, representing fasted and fed states. The results indicate that the current design and operating conditions of the disintegration test device, given by the pharmacopoeias, are not reproducing the in vivo situation. This holds true for the hydrodynamics in the disintegration tester that generates Reynolds numbers dissimilar to the reported in vivo situation. Also, when using homogenized US FDA meal, representing the fed state, too high viscosities and relative pressures are generated. The forces acting on the dosage form are too small for all fluids compared to the in vivo situation. The lack of peristaltic contractions, which generate hydrodynamics and shear stress in vivo, might be the major drawback of the compendial device resulting in the observed differences between predicted and in vivo measured hydrodynamics. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Structural, optical, mechanical and density functional theory studies of 1H-pyrazol-2-ium hydrogen oxalate crystal

Energy Technology Data Exchange (ETDEWEB)

Devi, P. Karthiga, E-mail: karthvi19@gmail.com; Venkatachalam, K.

2016-11-01

In the present work, we have grown 1H- pyrazol-2-ium hydrogen oxalate single crystal by slow evaporation solution growth technique. The lattice parameters are determined from single crystal X ray diffraction studies. The functional groups present in the compound are confirmed by Fourier transform infrared spectroscopy. UV-Vis analysis shows that the crystal has a wide transparency window. Vicker's hardness test has been carried out to estimate the stiffness constant, fracture toughness, brittleness index and yield strength of the crystal. Density functional study B3LYP method at 6-31 G (d, p) has been performed to study the optimized structure, HOMO-LUMO energy gap, hyperpolarizability and thermodynamic properties. - Highlights: • The title compound was analyzed using FTIR and UV–Vis spectroscopy. • Mechanical study was carried out using Vicker's hardness test. • Optimized molecular geometry was determined using DFT method. • Hydrogen bonding interaction was studied through NBO analysis.

Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys

Directory of Open Access Journals (Sweden)

Masafumi Matsushita

2011-07-01

Full Text Available Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V3Fe2Mo2 are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V3Fe2Mo2 alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride.

An Assessment of Mechanical and Tribological Property of Hybrid Aluminium Metal Matrix Composite

Directory of Open Access Journals (Sweden)

R. Santosh Kumar

2017-04-01

Full Text Available Composite materials has huge requirement in the area of automobile, aerospace, and wear resistant applications. This study presents the synthesis of composite reinforced with SiC and Al2O3 using gravity stir casting. Stir casting is the manufacturing process that is incorporated to produce the composite material because of its extreme bonding capacity with base material. The composition of reinforcement with 6061 aluminium matrix is SiC-7.5% and Al2O3 -2.5% respectively. The average size of reinforcement particle is 30-40 microns. The synthesised composite casting is machined using EDM to prepare specimens for various tests. Microstructure study was carried and the microstructure images prove the existence and dispersion of reinforcement particles in the metal matrix. There is no visible porosity is observed. The hardness of the specimen is tested using Vickers hardness tester and found considerable increase when compare with parent alloy Al 6061. Also mechanical and tribological properties of hybrid Aluminium metal matrix composite were employed. The fortifying material, Silicon Carbide is composed of tetrahedral of carbon and silicon atoms with strong bonds in crystal lattice along with its excellent wear resistance property and alumina have high strength and wear resistance. To avoid enormous material wastage and to achieve absolute accuracy, wire-cut EDM process is capitalised to engrave the specimen as per required dimensions. Three Tensile test specimens were prepared, in order to achieve reliability in results as per ASTM- E8 standard, and the values were tabulated. Impact test was carried out and the readings were tabulated. Wear test was carried out using pin on disc wear test apparatus and the results show considerable increase in wear resistant property when compare with parent alloy Al6061.The above work proves the successful fabrication of composite and evaluation of properties.

Preparation and characterization of squeeze cast-Al–Si piston alloy reinforced by Ni and nano-Al2O3 particles

Directory of Open Access Journals (Sweden)

Hashem F. El-Labban

2016-07-01

Full Text Available Al–Si base composites reinforced with different mixtures of Ni and nano-Al2O3 particles have been fabricated by squeeze casting and their metallurgical and mechanical characterization has been investigated. A mixture of Ni and nano-Al2O3 particles of different ratios was added to the melted Al–Si piston alloy at 700 °C and stirred under pressure. After the Al-base-nano-composites were fabricated by squeeze casting, the microstructure and the particle distribution inside the matrix have been investigated using optical and scanning electron microscopes. Moreover, the hardness and the tensile properties of the resulted Al-base-nano-composites were evaluated at room temperature by using Vickers hardness and universal tensile testers, respectively. As a result, in most cases, it was found that the matrix showed a fine eutectic structure of short silicon constituent which appeared in the form of islands in the α-phase around some added particle agglomerations of the nano-composite structures. The tendency of this structure formation increases with the increase of Ni particle addition. As the ratio of the added particles increases, the tendency of these particles to be agglomerated also increases. Regarding the tensile properties of the fabricated Al-base-nano-composites, ultimate tensile strength is increased by adding the Ni and nano-Al2O3 particles up to 10 and 2 wt.%, respectively. Moreover, the ductility of the fabricated composites is significantly improved by increasing the added Ni particles. The composite material reinforced with 5 wt.% Ni and 2 wt.% nano-Al2O3 particles showed superior ultimate tensile strength and good ductility compared with any other added particles in this investigation.

Patch testers' opinions regarding diagnostic criteria for metal hypersensitivity reactions to metallic implants.

Science.gov (United States)

Schalock, Peter C; Thyssen, Jacob P

2013-01-01

Metal hypersensitivity reactions to implanted devices remain a challenging and controversial topic. Diagnostic criteria and methods are not well delineated. Diagnostic criteria for hypersensitivity reactions after metallic device implantation are evaluated in this study by a multinational group of patch testers using Thyssen's previously published criteria. A total of 119 dermatologists at the 2012 European Contact Dermatitis Society and 2013 American Contact Dermatitis Society meetings answered a survey regarding their opinions on topics relating to metal hypersensitivity. Four major and 5 minor diagnostic criteria emerged. Approximately 80% of respondents found the following criteria useful (major criteria): chronic dermatitis beginning weeks to months after metallic implantation, eruption overlying the metal implant, positive patch test to a metal component of the implant, and complete clearing after removal of the potentially allergenic implant. Minor criteria (metals (eg, lymphocyte transformation test). In the challenging situation such as a symptomatic or failing orthopedic device, applying these 4 major criteria and the 5 supportive minor criteria may be useful for guiding decision making.

Calibrators measurement system for headlamp tester of motor vehicle base on machine vision

Science.gov (United States)

Pan, Yue; Zhang, Fan; Xu, Xi-ping; Zheng, Zhe

2014-09-01

With the development of photoelectric detection technology, machine vision has a wider use in the field of industry. The paper mainly introduces auto lamps tester calibrator measuring system, of which CCD image sampling system is the core. Also, it shows the measuring principle of optical axial angle and light intensity, and proves the linear relationship between calibrator's facula illumination and image plane illumination. The paper provides an important specification of CCD imaging system. Image processing by MATLAB can get flare's geometric midpoint and average gray level. By fitting the statistics via the method of the least square, we can get regression equation of illumination and gray level. It analyzes the error of experimental result of measurement system, and gives the standard uncertainty of synthesis and the resource of optical axial angle. Optical axial angle's average measuring accuracy is controlled within 40''. The whole testing process uses digital means instead of artificial factors, which has higher accuracy, more repeatability and better mentality than any other measuring systems.

Remember Hard but Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions

Directory of Open Access Journals (Sweden)

Jiushu Xie

2016-09-01

Full Text Available Previous studies have found that bodily stimulation, such as hardness, biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between hard and rigid and between soft and flexible in Chinese, to investigate whether the experience of hardness affected cognitive functions requiring either rigidity (memory or flexibility (creativity. In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition than a cushioned one (the soft condition. In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity and flexibility. They support the embodiment proposition that cognitive functions and representations could be grounded via metaphorical association in bodily states.

Examination of material manufactured by direct metal laser sintering (DMLS

Directory of Open Access Journals (Sweden)

J. Dobránsky

2015-07-01

Full Text Available This article is concerned with assessing microstructural properties of metal component manufactured by additive DMLS technology. Two series of samples were assessed. The first one was manufactured without heat treatment. Samples in the second series were treated with heat in order to assess increase in hardness and influence on modification of microstructure. Subsequently, values of hardness were measured by Vickers Hardness Test and modification of microstructure was observed by optical microscope. Evaluations were carried out in three planes in order to assess the differences in layering of material during its processing. Differences in values of hardness and microstructural components were discovered by examination of changes in three planes.

Influence of enzymatic maceration on the microstructure and microhardness of compact bone

International Nuclear Information System (INIS)

Yin Ling; Venkatesan, Sudharshan; Kalyanasundaram, Shankar; Qin Qinghua

2010-01-01

The cleaning of fresh bones to remove their soft tissues while maintaining their structural integrity is a basic and essential part of bone studies. The primary issue is how the cleaning process influences bone microstructures and mechanical properties. We cleaned fresh lamb femurs using enzymatic maceration in comparison with water maceration at room temperature. The microstructures of these compact bones were examined using scanning electron microscopy (SEM) and their porosities were quantified using image processing software. The bone microhardness was measured using a Vickers indentation tester for studying the mechanical properties. The results show that enzymatic maceration of compact bone resulted in a significant microhardness reduction in comparison with water maceration. However, enzymatic maceration did not cause any significant change of porosity in bone structures.

Influence of enzymatic maceration on the microstructure and microhardness of compact bone

Energy Technology Data Exchange (ETDEWEB)

Yin Ling [School of Engineering and Physical Sciences, James Cook University, Townsville, QLD 4811 (Australia); Venkatesan, Sudharshan; Kalyanasundaram, Shankar; Qin Qinghua, E-mail: ling.yin@jcu.edu.a [Department of Engineering, Australian National University, Canberra, ACT 0200 (Australia)

2010-02-15

The cleaning of fresh bones to remove their soft tissues while maintaining their structural integrity is a basic and essential part of bone studies. The primary issue is how the cleaning process influences bone microstructures and mechanical properties. We cleaned fresh lamb femurs using enzymatic maceration in comparison with water maceration at room temperature. The microstructures of these compact bones were examined using scanning electron microscopy (SEM) and their porosities were quantified using image processing software. The bone microhardness was measured using a Vickers indentation tester for studying the mechanical properties. The results show that enzymatic maceration of compact bone resulted in a significant microhardness reduction in comparison with water maceration. However, enzymatic maceration did not cause any significant change of porosity in bone structures.

Influence of steel composition and plastic deformation on the surface properties induced by low temperature thermochemical processing

DEFF Research Database (Denmark)

Bottoli, Federico

to the formation of a supersaturated solid solution known as expanded austenite, or S-Phase. Expanded austenite is characterized by high hardness, up to 1400 Vickers, and high compressive stresses in the surface region, which result in improved wear and fatigue resistance of the components. Along....../nitrocarburizing on the stress distribution. The experimental techniques applied entail X-ray diffraction (XRD), Glow Discharge Optical EmissionSpectroscopy (GD-OES), Scanning electron microscopy (SEM), light optical microscopy (LOM) and hardness measurement....

MITIGATION OF AGRICULTURAL ENERGY REQUIREMENT IN BANGLADESH USING MICROALGAE PRODUCTION

OpenAIRE

Mohammad Farzid Hasan; Syeda Zohra Halim; Choudhury Mohammad Shahariar; Noor Quddus

2013-01-01

A high quality joint between tool steel and stainless steel alloys is hard to achieve with the conventional welding process. In this study, a new process of joining semi-solid AISI D2 tool steel and AISI 304 stainless steel using a partial remelting method is proposed. Metallographic analysis and Vickers hardness tests were performed. The results obtained from investigating the basic geometries demonstrated a good joining quality that differs from the conventional process of welding or mechan...

The effect of time in the exposure of theobromine gel to enamel and surface hardness after demineralization with 1% citric acid

Science.gov (United States)

Irawan, M. I. P.; Noerdin, A.; Eriwati, Y. K.

2017-08-01

Theobromine is one of the alkaloid compounds that can be found in cacao (Theobroma cacao). It is said that theobromine can prevent enamel demineralization. The aim of this research was to evaluate the effect of different exposure times to 200 mg/L theobromine gel on enamel microhardness after demineralization in 1% citric acid. Twenty-eight specimens of human premolar teeth were divided into four groups and were immersed in 1% citric acid (pH 4) for 2.5 minutes. Then 200 mg/L theobromine gel was exposed to the specimens for 16 minutes (n = 7), 48 minutes (n = 7), and 96 minutes (n = 7). Enamel microhardness (KHN) values were tested using the Knoop Microhardness Tester (Shimadzu, Japan) using a 50-gram load for 5 seconds. A statistical test was performed using the Friedman test, Wilcoxon test, Kruskal-Wallis test, and Mann-Whitney test. The results showed a significant decrease, of microhardness values after demineralization with 1% citric acid. There was also a significant increase in hardness (penamel microhardness.

The effectiveness of different polymerization protocols for class II composite resin restorations.

NARCIS (Netherlands)

Jong, L.C.G. de; Opdam, N.J.M.; Bronkhorst, E.M.; Roeters, F.J.M.; Wolke, J.G.C.; Geitenbeek, B.

2007-01-01

OBJECTIVES: To investigate the effect of reduced light exposure times on Vickers hardness (VH) of class II composite resin restorations. METHODS: Class II restorations were made in vitro in three 2mm thick increments in a human molar. Two composite resins (Clearfil AP-X; Esthet-X) were polymerized

The effects of beam energy and substrate temperature on the tribological properties of hard-carbon films on aluminum

International Nuclear Information System (INIS)

Wei, R.; Wilbur, P.J.; Erdemir, A.; Kustas, F.M.

1992-01-01

Hard-carbon films were applied on flat 6061-T6 aluminum substrates using a broad-beam ion source operating on methane and producing carbonaceous ions with energies that varied from 250 to 1050 eV. Films were evaluated using a reciprocating alumina ball-on-flat sliding wear tester operating in an ambient air test environment. The films facilitated substantial reductions in friction coefficients to 0.08-0.2 from 0.4-0.7 for uncoated aluminum. At a sufficiently high normal load, the films failed and friction coefficients increased to the higher range. The best film caused this critical normal load to increase from less than 0.1 N for untreated aluminum to greater than 30 N. A near-optimal beam ion energy (450 eV) was identified for good quality films. At lower energies (e.g. 250 eV) films were discontinuous, while at higher energies (e.g. 1050 eV) high sputter rates limited film growth. When an aluminum flat was held at low temperature during processing, the films were smooth and adhered well, but they became rougher and adhered poorly as the temperature was increased above approximately 300degC. (orig.)

The effect of adding magnesium oxide on the mechanical properties of the tricalcium phosphate-zirconia composites

Energy Technology Data Exchange (ETDEWEB)

Sallemi, Imen, E-mail: imen.sallemi@hotmail.com; Bouaziz, Jamel; Ben Ayed, Foued

2015-02-01

The effect of magnesium oxide on the mechanical properties of the tricalcium phosphate – 50 wt.% zirconia composites was investigated during a sintering process between 1300 °C and 1400 °C. The characteristics of the samples before and after the sintering process were realized by using the differential thermal analysis, dilatometry, X-ray diffraction, the {sup 31}P magic angle scanning nuclear magnetic resonance, the scanning electron microscope and by considering such mechanical properties as the rupture strength and Vickers hardness. The mechanical performances of the tricalcium phosphate-50 wt.% zirconia composites increased with both the percentage of magnesium oxide and the sintering temperature. At 1400 °C, the mechanical properties of the composites sintered with 10 wt.% magnesium oxide reached their maximum value. Thus, Vickers hardness increased from 554 to 6350 MPa and the rupture strength of the corresponding composites varied from 5.2 to 25 MPa. The increase of the mechanical properties of the samples is due to the formation of both the tetragonal zirconia phase and the liquid phase which helps to fill the pores. The microstructure of needle form is most probably phosphate precipitates which are formed from this liquid phase. Furthermore, the presence of magnesium oxide in the composites prevented the inverse allotropic transformation of zirconia. - Highlights: • We measure the rupture strength and Vickers hardness of bioceramics. • We characterize the effect of MgO on the mechanical properties of the tricalcium phosphate – 50 wt% zirconia composites. • MgO increase the mechanical properties of the composites.

Effect of ion irradiation on the surface, structural and mechanical properties of brass

Science.gov (United States)

Ahmad, Shahbaz; Bashir, Shazia; Ali, Nisar; Umm-i-Kalsoom; Yousaf, Daniel; Faizan-ul-Haq; Naeem, Athar; Ahmad, Riaz; Khlaeeq-ur-Rahman, M.

2014-04-01

Modifications to the surface, structural and mechanical properties of brass after ion irradiation have been investigated. Brass targets were bombarded by carbon ions of 2 MeV energy from a Pelletron linear accelerator for various fluences ranging from 56 × 1012 to 26 × 1013 ions/cm2. A scanning electron microscope and X-ray diffractometer were utilized to analyze the surface morphology and crystallographic structure respectively. To explore the mechanical properties e.g., yield stress, ultimate tensile strength and microhardness of irradiated brass, an universal tensile testing machine and Vickers microhardness tester were used. Scanning electron microscopy results revealed an irregular and randomly distributed sputter morphology for a lower ion fluence. With increasing ion fluence, the incoherently shaped structures were transformed into dendritic structures. Nano/micro sized craters and voids, along with the appearance of pits, were observed at the maximum ion fluence. From X-ray diffraction results, no new phases were observed to be formed in the brass upon irradiation. However, a change in the peak intensity and higher and lower angle shifting were observed, which represents the generation of ion-induced defects and stresses. Analyses confirmed modifications in the mechanical properties of irradiated brass. The yield stress, ultimate tensile strength and hardness initially decreased and then increased with increasing ion fluence. The changes in the mechanical properties of irradiated brass are well correlated with surface and crystallographic modifications and are attributed to the generation, augmentation, recombination and annihilation of the ion-induced defects.

The Effect of Ag Addition on the Enhancement of the Thermal and Mechanical Properties of CuZrAl Bulk Metallic Glasses

Directory of Open Access Journals (Sweden)

Tsan-Man Chung

2016-09-01

Full Text Available In this study, the thermal and mechanical properties of Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 bulk metallic glasses (BMGs are investigated by using an X-ray diffractometer (XRD, a differential scanning calorimeter (DSC, differential thermal analysis (DTA, a Vickers hardness tester, a material test system (MTS, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 BMGs were made by arc-melting and an injection casting process. The results revealed that the glass transition temperature (Tg and the crystallization temperature (Tx of CuZrAl alloy decreased with the Ag addition. Hence, the supercooled liquid region and γ of Cu45Zr43Al7Ag5 alloy increased to 76 K and 0.42, respectively. The thermal stability and glass forming ability of CuZrAlAg BMG alloys were enhanced by the microalloyed Ag content. The room temperature compressive fracture strength and strain measured of Cu47Zr43Al7Ag3 were about 2200 MPa and 2.1%, respectively. The distribution of vein patterns and the formation of nanocrystalline phases on the fracture surface of Cu47Zr43Al7Ag3 alloy can be observed by SEM and TEM to be significant, indicating a typical ductile fracture behavior and an improved plasticity of alloys with the addition of microalloyed Ag from 0 to 6 atom %.

Hard coal; Steinkohle

Energy Technology Data Exchange (ETDEWEB)

Loo, Kai van de; Sitte, Andreas-Peter [Gesamtverband Steinkohle e.V., Herne (Germany)

2013-04-01

The year 2012 benefited from a growth of the consumption of hard coal at the national level as well as at the international level. Worldwide, the hard coal still is the number one energy source for power generation. This leads to an increasing demand for power plant coal. In this year, the conversion of hard coal into electricity also increases in this year. In contrast to this, the demand for coking coal as well as for coke of the steel industry is still declining depending on the market conditions. The enhanced utilization of coal for the domestic power generation is due to the reduction of the nuclear power from a relatively bad year for wind power as well as reduced import prices and low CO{sub 2} prices. Both justify a significant price advantage for coal in comparison to the utilisation of natural gas in power plants. This was mainly due to the price erosion of the inexpensive US coal which partly was replaced by the expansion of shale gas on the domestic market. As a result of this, the inexpensive US coal looked for an outlet for sales in Europe. The domestic hard coal has continued the process of adaptation and phase-out as scheduled. Two further hard coal mines were decommissioned in the year 2012. RAG Aktiengesellschaft (Herne, Federal Republic of Germany) running the hard coal mining in this country begins with the preparations for the activities after the time of mining.

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distinctively colored hard hats, or hard caps... STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

Hardness properties and microscopic investigation of crack- crystal interaction in SiO(2)-MgO-Al(2)O(3)-K(2)O-B(2)O(3)-F glass ceramic system.

Science.gov (United States)

Roy, Shibayan; Basu, Bikramjit

2010-01-01

In view of the potential engineering applications requiring machinability and wear resistance, the present work focuses to evaluate hardness property and to understand the damage behavior of some selected glass-ceramics having different crystal morphologies with SiO(2)-MgO-Al(2)O(3)-K(2)O-B(2)O(3)-F composition, using static micro-indentation tests as well as dynamic scratch tests, respectively. Vickers hardness of up to 5.5 GPa has been measured in glass-ceramics containing plate like mica crystals. Scratch tests at a high load of 50 Nin artificial saliva were carried out in order to simulate the crack-microstructure interaction during real-time abrasion wear and machining operation. The experimental observations indicate that the novel "spherulitic-dendritic shaped "crystals, similar to the plate like crystals, have the potential to hinder the scratching induced crack propagation. In particular, such potential of the 'spherulitic-dendritic' crystals become more effective due to the larger interfacial area with the glass matrix as well as the dendritic structure of each mica plate, which helps in crack deflection and crack blunting, to a larger extent.While modest damage tolerant behavior is observed in case of 'spherulitic-dendritic' crystal containing material, severe brittle fracture of plate like crystals were noted, when both were scratched at 50 N load.

MICROSTRUCTURE AND WEAR RESISTANCE OF COMPOSITE COATING BY LASER CLADDING Al/TiN ON THE Ti–6Al–4V SUBSTRATE

OpenAIRE

H. X. ZHANG; H. J. YU; C. Z. CHEN

2015-01-01

The composite coatings were fabricated by laser cladding Al/TiN pre-placed powders on Ti–6Al–4V substrate for enhancing wear resistance and hardness of the substrate. The composite coatings were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The sliding wear tests were performed by MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there...

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distinctively colored hard hats or hard caps... Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color from those worn by experienced miners shall be worn at...

Mechanical properties of polymer-infiltrated-ceramic-network materials.

Science.gov (United States)

Coldea, Andrea; Swain, Michael V; Thiel, Norbert

2013-04-01

To determine and identify correlations between flexural strength, strain at failure, elastic modulus and hardness versus ceramic network densities of a range of novel polymer-infiltrated-ceramic-network (PICN) materials. Four ceramic network densities ranging from 59% to 72% of theoretical density, resin infiltrated PICN as well as pure polymer and dense ceramic cross-sections were subjected to Vickers Indentations (HV 5) for hardness evaluation. The flexural strength and elastic modulus were measured using three-point-bending. The fracture response of PICNs was determined for cracks induced by Vickers-indentation. Optical and scanning electron microscopy (SEM) was employed to observe the indented areas. Depending on the density of the porous ceramic the flexural strength of PICNs ranged from 131 to 160MPa, the hardness values ranged between 1.05 and 2.10GPa and the elastic modulus between 16.4 and 28.1GPa. SEM observations of the indentation induced cracks indicate that the polymer network causes greater crack deflection than the dense ceramic material. The results were compared with simple analytical expressions for property variation of two phase composite materials. This study points out the correlation between ceramic network density, elastic modulus and hardness of PICNs. These materials are considered to more closely imitate natural tooth properties compared with existing dental restorative materials. Copyright © 2013 Academy of Dental Materials. All rights reserved.

Design and analysis of a toroidal tester for the measurement of core losses under axial compressive stress

Energy Technology Data Exchange (ETDEWEB)

Alatawneh, Natheer, E-mail: natheer80@yahoo.com [Department of Mining and Materials Engineering, McGill University, QC H3A 0G4 (Canada); Rahman, Tanvir; Lowther, David A. [Department of Electrical and Computer Engineering, McGill University, QC H3A 0E9 (Canada); Chromik, Richard [Department of Mining and Materials Engineering, McGill University, QC H3A 0G4 (Canada)

2017-06-15

Highlights: • Develop a toroidal tester for magnetic measurements under compressive axial stress. • The shape of the toroidal ring has been verified using 3D stress analysis. • The developed design has been prototyped, and measurements were carried out. • Physical explanations for the core loss trend due to stress are provided. - Abstract: Electric machine cores are subjected to mechanical stresses due to manufacturing processes. These stresses include radial, circumferential and axial components that may have significant influences on the magnetic properties of the electrical steel and hence, on the output and efficiencies of electrical machines. Previously, most studies of iron losses due to mechanical stress have considered only radial and circumferential components. In this work, an improved toroidal tester has been designed and developed to measure the core losses and the magnetic properties of electrical steel under a compressive axial stress. The shape of the toroidal ring has been verified using 3D stress analysis. Also, 3D electromagnetic simulations show a uniform flux density distribution in the specimen with a variation of 0.03 T and a maximum average induction level of 1.5 T. The developed design has been prototyped, and measurements were carried out using a steel sample of grade 35WW300. Measurements show that applying small mechanical stresses normal to the sample thickness rises the delivered core losses, then the losses decrease continuously as the stress increases. However, the drop in core losses at high stresses does not go lower than the free-stress condition. Physical explanations for the observed trend of core losses as a function of stress are provided based on core loss separation to the hysteresis and eddy current loss components. The experimental results show that the effect of axial compressive stress on magnetic properties of electrical steel at high level of inductions becomes less pronounced.

Erosion of heat-treated AISI 4140 steel

Energy Technology Data Exchange (ETDEWEB)

Goretta, K.C. (Materials and Components Tech. Div., Argonne National Lab., IL (United States)); Thompson, A.C. (Materials and Components Tech. Div., Argonne National Lab., IL (United States)); Routbort, J.L. (Materials Science Div., Argonne National Lab., IL (United States))

1993-03-15

Solid-particle erosion was studied on AISI 4140 steel heat treated to have a Vickers hardness (Hv) of 288-650 kg mm[sup -2]. The experiments were conducted in vacuum with 143 [mu]m Al[sub 2]O[sub 3] abrasive impacting at 50-100 m s[sup -1] at an angle of 30 or 90 . Erosion rates were nearly independent of hardness for Hv[<=]365 kg mm[sup -2], but increased with hardness for Hv>365 kg mm[sup -2]. The improved erosion resistances of the softer alloys were attributed to increased ductilities. (orig.). Letter-to-the-editor

Comparative studies of microstructural, tribological and corrosion properties of Zn-TiO2 and Zn-TiO2-WO3 nano-composite coatings

Directory of Open Access Journals (Sweden)

A.A. Daniyan

Full Text Available Nano sized composites of Zn-TiO2 and Zn-TiO2-WO3 were produced via electrocodeposition on plain carbon steel. The effect of input current on the microstructure, mechanical strengthening and corrosion properties were compared. The morphological features of the composite coatings were characterized by scanning electron microscope (SEM equipped with energy dispersive spectrometer (EDS; mechanical properties were carried out using a diamond base Dura Scan hardness tester and CERT UMT-2 multi-functional tribological tester. The corrosion properties were investigated by potentiodynamic studies in 3.5% NaCl. The result showed that the coatings exhibited good stability and the particle loading of WO3 greatly enhanced the microstructural properties, hardness behaviour and corrosion resistance of the coatings. Keywords: Zn-TiO2, Zn-TiO2-WO3, Electrocodeposition, Microstructure, Composite, Stability and coatings

Remodelación del probador de aceites WPOT 0.25/75; Remodelig of the WPOT0.25/75 oil tester

Directory of Open Access Journals (Sweden)

Ignat Pérez Almirall

2011-02-01

Full Text Available El objetivo fundamental de este trabajo es el rediseño del probador de aceites WPOT 0.25/75. Para estofue necesario rediseñar completamente todo su sistema de control y de protección pues el original ademásde estar constituido sobre la base de válvulas de vacío, no funcionaba ya que presentaba fallas en lossoportes aislantes de las mismas, fallas de dichas válvulas y fallas en la placa aislante que sirve desoporte a los componentes de los mecanismos de protección y control. Para solucionar estos problemasse diseñó un sistema de control con tiristores para la protección del equipo sustituyéndose por completoel obsoleto sistema de control a válvulas, lográndose un sistema de control seguro, confiable y de fáciloperación como para ser operado por personal con pocas habilidades.  The main objective of this paper is to remodel the WPOT 0.25/75 oil tester equipment. The originalequipment was made with vacuum valves, coupled on an insulated support. This equipment presentedseveral electrical failures on the insulated support and in the vacuum valves. In order to solve this problem,a new control and protecting system, using tiristor,  was designed . With this new design it was possibleto use this oil tester again. Moreover, the design offers better and new operating options useful for somespecial interesting tests.

Optimization of the Spent Fuel Attribute Tester using radiation transport calculations

International Nuclear Information System (INIS)

Laub, T.W.; Dupree, S.A.; Arlt, R.

1993-01-01

The International Atomic Energy Agency uses the Spent Fuel Attribute Tester (SFAT) to measure gamma signatures from fuel assemblies stored in spent fuel pools. It consists of a shielded, collimated NaI(Tl) detector attached to an air-filled pipe. The purpose of the present study was to define design changes, within operational constraints, that would improve the target assembly 137 Cs signal relative to the background signals from adjacent assemblies. This improvement is essential to reducing to an acceptable level the measurement time during an inspection. Monte Carlo calculations of the entire geometry were impractical, therefore, a hybrid method was developed that combined one-dimensional discrete ordinates models of the spent fuel pool, three-dimensional Monte Carlo calculations of the SFAT, and detector response calculations. The method compared well with measurements taken with the existing baseline SFAT. Calculations predicted significant improvements in signal-to-noise ratio. Recommended changes included shortening the pipe and increasing its wall thickness, placing low-Z filters in the crystal line of sight, reducing the thickness of shielding around the collimator aperture and adding shielding around the crystal, and reducing the diameter of the crystal. An instrument incorporating these design changes is being fabricated in Finland and will be tested this year

Mechanical Properties of Porous Titanium Structure Fabricated by Investment Casting with Pressurization/Depressurization System

International Nuclear Information System (INIS)

Kang, San; Lee, Ji-Woon; Hyun, Soong-Keun; Lee, Byong-Pil; Kim, Myoung-Gyun; Kim, Young-Jig

2014-01-01

A porous titanium structure was fabricated by investment casting with a pressurization/depressurization system, and its mechanical properties were studied. A Micro-Vickers hardness profile revealed that hardness gradually increased from the matrix to the metal/mold interface. A compression test was conducted on a single cell of the porous Ti structure. The theoretical and experimental values of yield strength were in good agreement. Such agreement suggested that the reaction layer did not affect the macro-mechanical properties of the porous Ti structure.

Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

Magnetic properties measurement of soft magnetic composite material (SOMALOY 700) by using 3-D tester

Science.gov (United States)

Asari, Ashraf; Guo, Youguang; Zhu, Jianguo

2017-08-01

Core losses of rotating electrical machine can be predicted by identifying the magnetic properties of the magnetic material. The magnetic properties should be properly measured since there are some variations of vector flux density in the rotating machine. In this paper, the SOMALOY 700 material has been measured under x, y and z- axes flux density penetration by using the 3-D tester. The calibrated sensing coils are used in detecting the flux densities which have been generated by the Labview software. The measured sensing voltages are used in obtaining the magnetic properties of the sample such as magnetic flux density B, magnetic field strength H, hysteresis loop which can be used to calculate the total core loss of the sample. The results of the measurement are analyzed by using the Mathcad software before being compared to another material.

Thermodynamic perturbation theory for fused hard-sphere and hard-disk chain fluids

International Nuclear Information System (INIS)

Zhou, Y.; Hall, C.K.; Stell, G.

1995-01-01

We find that first-order thermodynamic perturbation theory (TPT1) which incorporates the reference monomer fluid used in the generalized Flory--AB (GF--AB) theory yields an equation of state for fused hard-sphere (FHS) chain fluids that has accuracy comparable to the GF--AB and GF--dimer--AC theories. The new TPT1 equation of state is significantly more accurate than other extensions of the TPT1 theory to FHS chain fluids. The TPT1 is also extended to two-dimensional fused hard-disk chain fluids. For the fused hard-disk dimer fluid, the extended TPT1 equation of state is found to be more accurate than the Boublik hard-disk dimer equation of state. copyright 1995 American Institute of Physics

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHN V. VICKERS in the Bering Sea, North Pacific Ocean and South Pacific Ocean from 1992-08-16 to 1992-10-21 (NODC Accession 0115003)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115003 includes chemical, discrete sample, physical and profile data collected from JOHN V. VICKERS in the Bering Sea, North Pacific Ocean and South...

Precipitation hardening and hydrogen embrittlement of aluminum ...

Indian Academy of Sciences (India)

Hydrogen susceptibility of alloy AA7020 was evaluated by slow strain-rate tensile ... high pressures because of the embrittling effect of hydrogen. ... The higher the total Zn + Mg content,. ∗ .... dislocations, leading to a local softening of the slip plane, and thus to ... A Vickers hardness testing machine was used to measure the.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Structural characterization of the glasses was studied with respect to their thermal stability, refractive indices, third order nonlinear optical susceptibility, IR spectra and Vickers hardness. For four different prepared glasses, density in the range from 5.3744 to 6.0731 g.cm-1, the glass transition temperature (g) in the range ...

Wykorzystanie pomiarów mikrotwardości Vickersa do analiz wegla kamiennego pochodzacego z partii F kopalni Borynia-Zofiówka-Jastrzebie, Ruch Zofiówka

Czech Academy of Sciences Publication Activity Database

Godyń, K.; Králová, Lucie

2017-01-01

Roč. 19, č. 1 (2017), s. 25-33 ISSN 1643-1030 Institutional support: RVO:68145535 Keywords : Vickers microhardness * hard coal * Upper Silesian Coal Basin (USCB) Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Mining and mineral processing http://www.img-pan.krakow.pl/index.php/pl/wydawnictwa/prace-img-pan/2016.html

Assessing Hepatitis C Burden and Treatment Effectiveness through the British Columbia Hepatitis Testers Cohort (BC-HTC): Design and Characteristics of Linked and Unlinked Participants.

Science.gov (United States)

Janjua, Naveed Zafar; Kuo, Margot; Chong, Mei; Yu, Amanda; Alvarez, Maria; Cook, Darrel; Armour, Rosemary; Aiken, Ciaran; Li, Karen; Mussavi Rizi, Seyed Ali; Woods, Ryan; Godfrey, David; Wong, Jason; Gilbert, Mark; Tyndall, Mark W; Krajden, Mel

2016-01-01

The British Columbia (BC) Hepatitis Testers Cohort (BC-HTC) was established to assess and monitor hepatitis C (HCV) epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals. The BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV), HIV or active tuberculosis (TB) in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992) of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals. Of 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54%) were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90-100%). Linkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV.

Assessing Hepatitis C Burden and Treatment Effectiveness through the British Columbia Hepatitis Testers Cohort (BC-HTC: Design and Characteristics of Linked and Unlinked Participants.

Directory of Open Access Journals (Sweden)

Naveed Zafar Janjua

Full Text Available The British Columbia (BC Hepatitis Testers Cohort (BC-HTC was established to assess and monitor hepatitis C (HCV epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals.The BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV, HIV or active tuberculosis (TB in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992 of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals.Of 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54% were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90-100%.Linkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV.

Assessing Hepatitis C Burden and Treatment Effectiveness through the British Columbia Hepatitis Testers Cohort (BC-HTC): Design and Characteristics of Linked and Unlinked Participants

Science.gov (United States)

Janjua, Naveed Zafar; Kuo, Margot; Chong, Mei; Yu, Amanda; Alvarez, Maria; Cook, Darrel; Armour, Rosemary; Aiken, Ciaran; Li, Karen; Mussavi Rizi, Seyed Ali; Woods, Ryan; Godfrey, David; Wong, Jason; Gilbert, Mark; Tyndall, Mark W.; Krajden, Mel

2016-01-01

Background The British Columbia (BC) Hepatitis Testers Cohort (BC-HTC) was established to assess and monitor hepatitis C (HCV) epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals. Methods The BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV), HIV or active tuberculosis (TB) in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992) of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals. Results Of 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54%) were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90–100%). Conclusion Linkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV

Hard-on-hard lubrication in the artificial hip under dynamic loading conditions.

Directory of Open Access Journals (Sweden)

Robert Sonntag

Full Text Available The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal.

Remember Hard But Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions

Science.gov (United States)

Xie, Jiushu; Lu, Zhi; Wang, Ruiming; Cai, Zhenguang G.

2016-01-01

Previous studies have found that bodily stimulation, such as hardness biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between “hard” and “rigid” and between “soft” and “flexible” in Chinese, to investigate whether the experience of hardness affects cognitive functions whose performance depends prospectively on rigidity (memory) and flexibility (creativity). In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition) than a cushioned one (the soft condition). In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity or flexibility. They support the embodiment proposition that cognitive functions and representations can be grounded in bodily states via metaphorical associations. PMID:27672373

Structure-property correlations in nanocrystalline Al-Zr alloy composites

International Nuclear Information System (INIS)

Rittner, M.N.; Argonne National Lab., IL; Weertman, J.R.; Eastman, J.A.

1996-01-01

A study of the structure, grain size stability and Vickers microhardness of nanocrystalline aluminum-zirconium alloy composites was conducted. Samples were synthesized by the inert gas condensation process with electron beam evaporation. Transmission electron microscope examinations of the samples were performed at room and elevated temperatures. The behavior of the microstructures of the samples with time and temperature was investigated as a function of specimen composition. Vickers microhardness data were evaluated at room temperature in as-produced and polished compacted specimens. The local chemical composition of individual microhardness indents and average values of the grain size and porosity level were determined for a number of samples. Correlations among these microstructural variables and hardness were determined using multiple regression techniques

Main varieties of bread (Triticum aestivum L.) and durum (Triticum durum Desf.) wheat.

OpenAIRE

М. П. Чебаков

2008-01-01

Results of systematization and morphological characteristics of two wheat species-bread (Triticum aestivum L.) and hard (Triticum durum Desf.) are given. Detail descriptions of 55 main varieties of bread wheat and 32 varieties of hard wheat arep- resented in table version. In practical application these result enable plant breeders, seed producers and variety testers to determine wheat varieties easily sinse it is method for morphological systematics of wheat.

Main varieties of bread (Triticum aestivum L. and durum (Triticum durum Desf. wheat.

Directory of Open Access Journals (Sweden)

М. П. Чебаков

2008-04-01

Full Text Available Results of systematization and morphological characteristics of two wheat species-bread (Triticum aestivum L. and hard (Triticum durum Desf. are given. Detail descriptions of 55 main varieties of bread wheat and 32 varieties of hard wheat arep- resented in table version. In practical application these result enable plant breeders, seed producers and variety testers to determine wheat varieties easily sinse it is method for morphological systematics of wheat.

Metallurgical characterization of new palladium-containing cobalt chromium and nickel chromium alloys

Science.gov (United States)

Puri, Raghav

Recently introduced to the market has been an entirely new subclass of casting alloy composition whereby palladium (˜25 wt%) is added to traditional base metal alloys such as CoCr and NiCr. Objectives. The purpose of this study was to evaluate the microstructure and Vickers hardness of two new CoPdCr and one new NiPdCr alloy and compare them to traditional CoCr and NiCr alloys. Methods. The casting alloys investigated were: CoPdCr-A (Noble Crown NF, The Argen Corporation), CoPdCr-I (Callisto CP+, Ivoclar Vivadent), NiPdCr (Noble Crown, Argen), CoCr (Argeloy N.P. Special, Argen), and NiCr (Argeloy N.P. Star, Argen). As-cast cylindrical alloy specimens were mounted in epoxy resin and prepared with standard metallographic procedures, i.e. grinding with successive grades of SiC paper and polishing with alumina suspensions. The alloys were examined with an optical microscope, SEM/EPMA, and XRD to gain insight into their microstructure, composition, and crystal structure. Vickers hardness (VHN) was measured and statistically analyzed by one way ANOVA and Tukey's HSD test (alpha=0.05). Results. Optical microscopy showed a dendritic microstructure for all alloys. The Pd-containing alloys appear to possess a more complex microstructure. SEM/EPMA showed Cr to be rather uniformly distributed in the matrix with palladium tending to be segregated apart from Mo and Ni or Co. Areas of different composition may explain the poor electrochemical results noted in previous studies. XRD suggested the main phase in the Ni-containing solutions was a face centered cubic Ni solid solution, whereas the CoCr exhibited a hexagonal crystal structure that was altered to face centered cubic when Pd was included in the composition. For Vickers hardness, the Co-containing alloys possessed a greater hardness than the Ni-containing alloys. However, the incorporation of Pd in CoCr and NiCr had only a slight effect on microhardness. Conclusion. Overall, the inclusion of palladium increases the

Concurrent strengthening of ultrafine-grained age-hardenable Al-Mg alloy by means of high-pressure torsion and spinodal decomposition

International Nuclear Information System (INIS)

Tang, Yongpeng; Goto, Wataru; Hirosawa, Shoichi; Horita, Zenji; Lee, Seungwon; Matsuda, Kenji; Terada, Daisuke

2017-01-01

In this study, the age-hardening behavior and precipitate microstructures of severely-deformed and then artificially-aged Al-13.4 wt%Mg alloy has been investigated by Vickers hardness test, X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and atom probe tomography (APT). The combined processing of high-pressure torsion (HPT) and aging treatment at a temperature below spinodal lines results in a higher attained hardness of ∼HV296 with an age-hardenability (i.e ΔHV31 ± 2) comparable to that of the undeformed specimen without HPT (i.e. ΔHV33 ± 2). The corresponding TEM microstructures consist of modulated structures associated with spinodal decomposition, and quantitative estimation of the amplitude, as well as the wavelength, of Mg fluctuations was successfully conducted by APT for the first time for this alloy system. The linear relationship between the increment of Vickers hardness and the estimated amplitude of the undeformed specimen supposed that Kato's spinodal-hardening mechanism works even in the HPTed specimen with a high number density of grain boundaries. Therefore, our proposed strategy; i.e. taking advantage of spinodal decomposition, is regarded as a convincing approach to achieving concurrent strengthening by ultrafine-grained and precipitation hardenings for the alloys that decompose via spinodal decomposition.

Extracorporeal shockwave enhanced regeneration of fibrocartilage in a delayed tendon-bone insertion repair model.

Science.gov (United States)

Chow, Dick Ho Kiu; Suen, Pui Kit; Huang, Le; Cheung, Wing-Hoi; Leung, Kwok-Sui; Ng, Chun; Shi, San Qiang; Wong, Margaret Wan Nar; Qin, Ling

2014-04-01

Fibrous tissue is often formed in delayed healing of tendon bone insertion (TBI) instead of fibrocartilage. Extracorporeal shockwave (ESW) provides mechanical cues and upregulates expression of fibrocartilage-related makers and cytokines. We hypothesized that ESW would accelerate fibrocartilage regeneration at the healing interface in a delayed TBI healing model. Partial patellectomy with shielding at the TBI interface was performed on 32 female New Zealand White Rabbits for establishing this delayed TBI healing model. The rabbits were separated into the control and ESW group for evaluations at postoperative week 8 and 12. Shielding was removed at week 4 and a single ESW treatment was applied at week 6. Fibrocartilage regeneration was evaluated histomorphologically and immunohistochemically. Vickers hardness of the TBI matrix was measured by micro-indentation. ESW group showed higher fibrocartilage area, thickness, and proteoglycan deposition than the control in week 8 and 12. ESW increased expression of SOX9 and collagen II significantly in week 8 and 12, respectively. ESW group showed a gradual transition of hardness from bone to fibrocartilage to tendon, and had a higher Vickers hardness than the control group at week 12. In conclusion, ESW enhanced fibrocartilage regeneration at the healing interface in a delayed TBI healing model. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Tribological behavior at elevated temperature of multilayer TiCN/TiC/TiN hard coatings produced by chemical vapor deposition

International Nuclear Information System (INIS)

Bao Mingdong; Xu Xuebo; Zhang Haijun; Liu Xiaoping; Tian Linhai; Zeng Zhaoxin; Song Yubin

2011-01-01

Multilayer hard coatings of TiCN/TiC/TiN on high speed steel substrates were deposited using a chemical vapor deposition system. Evaluations of microstructure, wear morphology of coatings were characterized by scanning electron microscopy, and optical microscopy. Friction coefficient and wear rates of coatings were investigated using ball-on-disk tester sliding against a WC ball at a constant load of 20 N. Tribological behavior of the coatings at room and elevated temperature were discussed. Different changing tendency of friction coefficient were observed from ball-on-disc experiments. Results showed that the friction coefficient of coatings increased gradually to a highest value, then to a relatively constant value at room temperature dry sliding wear. The friction coefficient exhibited a reverse variation tendency at temperature of 550 °C. It got a higher value at the first sliding friction cycles. Then the value of friction coefficient decreased, suffered irregular oscillations and kept a relatively lower value with increasing sliding time. Reasons of the variation of friction coefficient with sliding time and wear mechanism were analyzed and discussed at room and elevated temperatures, respectively.

Microbiological quality of soft, semi-hard and hard cheeses during the shelf-life

Directory of Open Access Journals (Sweden)

Josip Vrdoljak

2016-03-01

Full Text Available Cheeses as ready-to-eat food should be considered as a potential source of foodborne pathogens, primarily Listeria monocytogenes. The aim of present study was to determine the microbiological quality of soft, semi-hard and hard cheeses during the shelf-life, with particular reference to L. monocytogenes. Five types of cheeses were sampled at different timepoints during the cold storage and analyzed for presence of Salmonella and L. monocytogenes, as well as lactic acid bacteria, Escherichia coli, coagulase-positive staphylococci, yeasts, molds, sulfite-reducing clostridia and L. monocytogenes counts. Water activity, pH and NaCl content were monitored in order to evaluate the possibility of L. monocytogenes growth. Challenge test for L. monocytogenes was performed in soft whey cheese, to determine the growth potential of pathogen during the shelf-life of product. All analyzed cheeses were compliant with microbiological criteria during the shelf-life. In soft cheeses, lactic acid bacteria increased in the course of the shelf-life period (1.2-2.6 log increase, while in semi-hard and hard cheeses it decreased (1.6 and 5.2 log decrease, respectively. Soft cheeses support the growth of L. monocytogenes according to determined pH values (5.8-6.5, water activity (0.99-0.94, and NaCl content (0.3-1.2%. Challenge test showed that L. monocytogenes growth potential in selected soft cheese was 0.43 log10 cfu/g during 8 days at 4°C. Water activity in semi-hard and hard cheeses was a limiting factor for Listeria growth during the shelf-life. Soft, semi-hard and hard cheeses were microbiologically stable during their defined shelf-life. Good manufacturing and hygienic practices must be strictly followed in the production of soft cheeses as Listeria-supporting food and be focused on preventing (recontamination.

Analytical Modeling of Hard-Coating Cantilever Composite Plate considering the Material Nonlinearity of Hard Coating

Directory of Open Access Journals (Sweden)

Wei Sun

2015-01-01

Full Text Available Due to the material nonlinearity of hard coating, the coated structure produces the nonlinear dynamical behaviors of variable stiffness and damping, which make the modeling of hard-coating composite structure become a challenging task. In this study, the polynomial was adopted to characterize this material nonlinearity and an analytical modeling method was developed for the hard-coating composite plate. Firstly, to relate the hard-coating material parameters obtained by test and the analytical model, the expression of equivalent strain of composite plate was derived. Then, the analytical model of hard-coating composite plate was created by energy method considering the material nonlinearity of hard coating. Next, using the Newton-Raphson method to solve the vibration response and resonant frequencies of composite plate and a specific calculation procedure was also proposed. Finally, a cantilever plate coated with MgO + Al2O3 hard coating was chosen as study case; the vibration response and resonant frequencies of composite plate were calculated using the proposed method. The calculation results were compared with the experiment and general linear calculation, and the correctness of the created model was verified. The study shows the proposed method can still maintain an acceptable precision when the material nonlinearity of hard coating is stronger.

The technology development for surveillance test of RPV materials 2

International Nuclear Information System (INIS)

Chang, Kee Ok; Lee, Sam Lai; Kim, Byoung Chul; Choi, Sun Pil; Choi, Kwen Jai

1998-12-01

Irradiation-induced changes in mechanical properties and magnetic parameters were measured and compared to explore possible correlations for Mn-Mo-Ni low alloy steel surveillance specimens which were irradiated to a neutron fluence of 2.4 x 10 1 9n/cm 2 (E≥1.0 MeV) in a typical pressurized water reactor environment at about 288 deg C. For mechanical property parameters, microvickers hardness, tensile and Charpy impact test were performed and Barkhausen Noise(BN) amplitude, coercivity, maximum induction were measured for magnetic parameters, respectively. Results of mechanical property measurements showed an increase in yield and tensil strength, microvickers hardness 41J indexed RT NDT and a decrease in upper shelf energy irrespective of base and weld metals. In the case of magnetic measurements, it is found that magnetic remanence, BN amplitude, BN energy have dropped significantly but coercivity has increased rapidly after irradiation. For isothermally heat treated condition of irradiated specimen, BN energy has increased while Vickers microhardness has decreased. Results of BNE and Vickers microhardness are reversed to the results on irradiated condition. All these consistent changes in magnetic parameter and Vickers microhardness measurement, which are thought to be resulted from the interaction between irradiation-induced defects and dislocation, and magnetic domain, respectively, show a possibility that magnetic measurement may be used to the evaluation of material degradation and recovery due to neutron irradiation and heat treatment, respectively, if a relevant large database is prepared. (author). 49 refs., 7 tabs., 23 figs

The effects of barium sufate and iodide compound on the characteristics of dental acrylic resins

International Nuclear Information System (INIS)

Lee, Yong Keun; Lee, Keon Il; Jung, Sung Woo

1996-01-01

Aspiratin or swallowing foreign bodies is a common occurrence. If they are wholly or partly radiopaque, their localization in and progress through the gastrointestinal tract can be more effective. Of the dental origin foreign materials swallowed, the most common things are fragments of anterior maxillary partial denture. But the radiopacity of denture base resins is not sufficient to determine the location of the objects. The purpose of this study was to develop a radiopaque dental acrylic resin, which has clinically detectable radiopacity with minimal change of mechanical properties and color. the radiopacity, color change (CIE E) and microhardness of acrylic resins were determined after mixing barium sulfate or iolide compound. Thermocycling course was conducted to deter mine the change of characteristic of resins after using for a long time I the mouth. Five or ten percent of barium sulfa te to total weight of cured material was mixed with heat curing dental acrylic resin or chemically curing orthodontic re sin. In the case of iodide compound, the mixing ratio was two or three percent. After mixing the high radiopaque material s, resin was cured to 20X20X2 mm plate, polished with 600 sand paper and finally polished with Microcloth (Buehler). T he specimens were thermocycled in 5 and 55 degree distilled water for 2,000 times, and the measurement of radiopacity, color and Vickers hardness was repeated every 500 times thermocycling. The radiopacity of specimens on the X-ray films was measured with densitometer (X-rite). The color change was determined with differential colorimeter (Model TC-6FX, Tokyo Denshoku), and the Vickers hardness number was measured with microhardness tester (Mitsuzawa). The following results were obtained : 1. All the three variables, the kinds of acrylic resins, the mixing or the kinds radiopaque materials and thermocycling , had combined effect on the radiopacity of the dental acrylic resins (p<0.01). 2. The two variables, the mixing or

The effects of barium sufate and iodide compound on the characteristics of dental acrylic resins

Energy Technology Data Exchange (ETDEWEB)

Lee, Yong Keun; Lee, Keon Il; Jung, Sung Woo [Dept. of Oral Radiology, College of Dentistry, Wonkwang University, Iksan(Korea, Republic of)

1996-08-15

Aspiratin or swallowing foreign bodies is a common occurrence. If they are wholly or partly radiopaque, their localization in and progress through the gastrointestinal tract can be more effective. Of the dental origin foreign materials swallowed, the most common things are fragments of anterior maxillary partial denture. But the radiopacity of denture base resins is not sufficient to determine the location of the objects. The purpose of this study was to develop a radiopaque dental acrylic resin, which has clinically detectable radiopacity with minimal change of mechanical properties and color. the radiopacity, color change (CIE E) and microhardness of acrylic resins were determined after mixing barium sulfate or iolide compound. Thermocycling course was conducted to deter mine the change of characteristic of resins after using for a long time I the mouth. Five or ten percent of barium sulfa te to total weight of cured material was mixed with heat curing dental acrylic resin or chemically curing orthodontic re sin. In the case of iodide compound, the mixing ratio was two or three percent. After mixing the high radiopaque material s, resin was cured to 20X20X2 mm plate, polished with 600 sand paper and finally polished with Microcloth (Buehler). T he specimens were thermocycled in 5 and 55 degree distilled water for 2,000 times, and the measurement of radiopacity, color and Vickers hardness was repeated every 500 times thermocycling. The radiopacity of specimens on the X-ray films was measured with densitometer (X-rite). The color change was determined with differential colorimeter (Model TC-6FX, Tokyo Denshoku), and the Vickers hardness number was measured with microhardness tester (Mitsuzawa). The following results were obtained : 1. All the three variables, the kinds of acrylic resins, the mixing or the kinds radiopaque materials and thermocycling , had combined effect on the radiopacity of the dental acrylic resins (p<0.01). 2. The two variables, the mixing or

Alpha radiation and in-pile annealing effects on the fracture properties of a sintered alumino borosilicate glass

International Nuclear Information System (INIS)

Bevilacqua, Arturo M.; Prado, Miguel O.; Messi de Bernasconi, Norma B.; Heredia, Arturo D.; Sanfilippo, Miguel

1999-01-01

The alpha radiation and the in-pile during irradiation effects on the hardness, the crack nucleation and the fracture toughness of the German alumino borosilicate glass SG7 were investigated by using the Vickers indentation. Cold pressed and sintered samples were irradiated with thermal neutrons, in the Argentine nuclear reactors RA-3 and RA-6, to produce alpha particles in the whole volume of the glass by means of the (n, alpha)-reaction with B-10. The Vickers hardness, the crack nucleation, as 50 percent fracture probability load, plotted as the Weibull's fracture probability distribution function and the fracture toughness, as critical stress intensity factor K Ic , were correlated to the four cumulative disintegration values. It was ascertained that: a) the Vickers hardness decreases from 5.6 GPa for the non-irradiated sample up to 4.7 GPa for the sample irradiated 70 h at the lower neutron flux (4.0 x 10 - sup 18 - alpha disintegration per cm - sup 3 -), b) the 50 % fracture probability load increases from 1.4 N for the non-irradiated sample up to 4.7 g for the sample irradiated 22 h at the higher flux (6.8 x 10 - sup 18 - alpha disintegration per cm - sup 3 -), and c) the stress intensity factor increases from 0.80 MPa.m - sup 1/2 - for the non irradiated sample up to 0.86 MPa.m - sup 1/2 - for the sample mentioned in b). The in-pile annealing was analyzed by comparing the crack nucleation after irradiation with data obtained by heavy ion irradiation followed by thermal annealing. Results for the SG7 glass were compared to those for soda-lime and borosilicate glasses. (author)

Effects of Ti and TiC ceramic powder on laser-cladded Ti-6Al-4V in situ intermetallic composite

CSIR Research Space (South Africa)

Ochonogora, OF

2012-12-01

Full Text Available carried out with the aid of three body abrasion tester. The resultant microstructure show homogeneous distribution of TiC particles free from cracks and pores. Multiple track deposited systems with 50% overlap revealed micro-hardness increase from 357.3 HV...

Effect of hydrogenation pressure on microstructure and mechanical properties of Ti-13Nb-13Zr alloy produced by powder metallurgy

International Nuclear Information System (INIS)

Duvaizem, Jose Helio; Galdino, Gabriel Souza; Bressiani, Ana Helena; Faria Junior, Rubens Nunes de; Takiishi, Hidetoshi

2009-01-01

The effects of the hydrogenation stage on microstructure and mechanical properties of Ti-13Nb-13Zr alloy produced by powder metallurgy have been studied. Powder alloys have been produced by hydrogenation with 250 MPa or 1 GPa and via high energy planetary ball milling. Samples were isostatically pressed at 200 MPa and sintered at 1150 deg C for 7, 10 and 13 hours. Elastic modulus and microhardness were determined using a dynamic mechanical analyzer (DMA) and a Vickers microhardness tester. Density of the samples was measured using a liquid displacement system. Microstructure and phases presents were analyzed employing scanning electron microscopy (SEM). Elastic modulus were 81.3 ± 0.8 and 62.6 ± 0.6 GPa for samples produced by 250 MPa and 1 GPa hydrogenation, respectively when sintered for 7h. (author)

Chemical hardness and density functional theory

Indian Academy of Sciences (India)

Unknown

RALPH G PEARSON. Chemistry Department, University of California, Santa Barbara, CA 93106, USA. Abstract. The concept of chemical hardness is reviewed from a personal point of view. Keywords. Hardness; softness; hard & soft acids bases (HSAB); principle of maximum hardness. (PMH) density functional theory (DFT) ...

Hardness variability in commercial technologies

International Nuclear Information System (INIS)

Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

1994-01-01

The radiation hardness of commercial Floating Gate 256K E 2 PROMs from a single diffusion lot was observed to vary between 5 to 25 krad(Si) when irradiated at a low dose rate of 64 mrad(Si)/s. Additional variations in E 2 PROM hardness were found to depend on bias condition and failure mode (i.e., inability to read or write the memory), as well as the foundry at which the part was manufactured. This variability is related to system requirements, and it is shown that hardness level and variability affect the allowable mode of operation for E 2 PROMs in space applications. The radiation hardness of commercial 1-Mbit CMOS SRAMs from Micron, Hitachi, and Sony irradiated at 147 rad(Si)/s was approximately 12, 13, and 19 krad(Si), respectively. These failure levels appear to be related to increases in leakage current during irradiation. Hardness of SRAMs from each manufacturer varied by less than 20%, but differences between manufacturers are significant. The Qualified Manufacturer's List approach to radiation hardness assurance is suggested as a way to reduce variability and to improve the hardness level of commercial technologies

Microstructure and deuterium retention after ion irradiation of W–Lu{sub 2}O{sub 3} composites

Energy Technology Data Exchange (ETDEWEB)

Lin, Jin–Shan [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Luo, Lai–Ma, E-mail: luolaima@126.com [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province, Hefei 230009 (China); Xu, Qiu [Research Reactor Institute, Kyoto University, Osaka-fu 590-0494 (Japan); Zan, Xiang; Zhu, Xiao–Yong [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province, Hefei 230009 (China); Wu, Yu–Cheng, E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province, Hefei 230009 (China)

2017-07-15

W–3Lu{sub 2}O{sub 3} composites were prepared by mechanical milling and spark plasma sintering. The obtained composites were subjected to He{sup +} irradiation experiments. The irradiated samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and measurement of Vickers hardness. Thermal desorption spectroscopy analysis was performed to analyze the samples at different damage levels after Fe{sup 2+} and D{sup +} irradiation. Results showed varied degrees of He{sup +} damage under different energies. Fuzz structures were observed on the surface of the material after irradiation. TEM results indicated that the existence of these fuzz structures was related to the formation of He bubbles. Amorphous, polycrystalline, and γ-W phases formed in areas where He bubbles existed. The measured Vickers hardness proved that radiation hardening occurred after irradiation. After Fe{sup 2+} irradiation at different damage levels, the total retained deuterium amount of W–3Lu{sub 2}O{sub 3} and pure W differed, and the impact of Fe{sup 2+} radiation for deuterium retention on pure tungsten was greater.

Microstructure and deuterium retention after ion irradiation of W–Lu2O3 composites

International Nuclear Information System (INIS)

Lin, Jin–Shan; Luo, Lai–Ma; Xu, Qiu; Zan, Xiang; Zhu, Xiao–Yong; Wu, Yu–Cheng

2017-01-01

W–3Lu 2 O 3 composites were prepared by mechanical milling and spark plasma sintering. The obtained composites were subjected to He + irradiation experiments. The irradiated samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and measurement of Vickers hardness. Thermal desorption spectroscopy analysis was performed to analyze the samples at different damage levels after Fe 2+ and D + irradiation. Results showed varied degrees of He + damage under different energies. Fuzz structures were observed on the surface of the material after irradiation. TEM results indicated that the existence of these fuzz structures was related to the formation of He bubbles. Amorphous, polycrystalline, and γ-W phases formed in areas where He bubbles existed. The measured Vickers hardness proved that radiation hardening occurred after irradiation. After Fe 2+ irradiation at different damage levels, the total retained deuterium amount of W–3Lu 2 O 3 and pure W differed, and the impact of Fe 2+ radiation for deuterium retention on pure tungsten was greater.

Influence of polymerization time and depth of cure of resin composites determined by Vickers hardness