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The mechanism of cancer cell death induced by hydrogen discharged from Pd-5at.% Ni hydrogen storage alloy has been investigated. Cancer cell (HeLa: cervical cancer cell) death was observed in the limited region within ~ 3 mm from the sample. The measurement of surviving fraction of cells revealed that almost all the cancer cells in the well of 96-well multi plate, 6.2 mm in diameter were extinct (p < 0.01), while no detectable influence was observed in the normal cells. From the fluorescent imaging experiment, it was indicated that the cell death induced by discharged hydrogen was due to the "Apoptosis" and hydrogen peroxide was detected in both intracellular and extracellular regions. Furthermore, the generation of hydrogen radical and hydroxyl radical was observed in the ESR measurement. From the results obtained, the mechanism of cancer cell death is proposed., 2013 International Conference on Materials Science and Chemical Engineering, MSCE 2013; ; 20 February 2013 ～ 21 February 2013, Advanced Materials Research, 699, pp.284-290; 2013

Neuron-like gold-palladium (AuPd) alloy nanostructures were synthesized by simultaneous reduction of AuCl4(-) and PdCl4(2-) with ascorbic acid, using N-methylimidazole as the structure-director and stabilizing agent. The synthesis method was simple and seedless, without any template or polymer. The architectures strongly depended on the concentration of N-methylimidazole, reaction temperature and time, and hence the formation mechanism was described in detail. The as-obtained architectures exhibited superior electrocatalytic activity for ethanol oxidation and surface-enhanced Raman scattering (SERS) responses, owing to their unique nanostructures with high density of steps, edges, and corners on their branches, along with the synergetic functions between Au and Pd.

The study of the Fleischmann and Pons Effect (FPE), i.e. the production of excess power production during electrochemical loading of deuterium in palladium (in the past labeled as cold fusion) has had of noticeable multidisciplinary character, involving as solid state and nuclear physics, material science, electrochemistry and others. Correlation between the material status and the occurrence of the effect as well as some changing of the electrochemical interface status have been observed. Although during the last two decades in several calorimetric experiments the effect was observed to be well above the measurement uncertainties, the mechanism producing the excess power is not completely understood. The lack of reproducibility has been so far responsible for the absence of a clear explanation of the phenomenon based on measurement chains conceived to enhance the spectrum of information required to define the effect. Recently, In order to improve this aspect of this research, a specific work has been carried out in order to investigate if the excess power was produced concurrently with the emission of Radio Frequency from the active cathode. Suitable probes and triggering included into the RF measurement chain allowed to reveal RF signal emission during electrochemical loading of Pd samples and a correlation between the heat production, in active samples, and RF signals emission was found. The preliminary results are highlighting the importance of performing studies on the electrodynamic effects that may be involved in the phenomenon and in the design of appropriate instruments conceived to investigate unexplored regions of metal hydrogen systems. © 2016 ISCMNS.

We compare the kinetics of the formation of an ordered structure in the Cu-49 at % Pd alloy in various initial states and demonstrate that the alloy can be brought into a single-phase, B2-ordered state, at variance with the commonly accepted Cu-Pd phase diagram. The alloy in this structural state has an extremely low resistivity: ρ = 5.48 × 10−8 Ω m.

This two-part article takes a critical look at how various trial designs of palladium alloy membrane systems are being employed to maximise the efficient production of high-density hydrogen – a potentially significant chemical constituent and energy source. The first part, which appears here, looks at the economic viability of hydrogen production and reviews various technologies used to generate the gas. It provides a summary of the categories of membrane technology that are available for trial designs of hydrogen separation and purification systems, major sources of value for metallic membranes and the areas where high-density hydrogen is needed.

A key discovery in the last two decades has been the realisation that gold, when prepared as supported nanoparticles, is exceptionally effective as a redox catalyst. The catalytic efficacy is enhanced further by the alloying of gold with palladium and this is particularly exemplified for the direct synthesis of hydrogen peroxide where supported gold palladium alloy nanoparticles are found to be highly active. In this paper we report a study of ceria-supported gold, palladium and gold–palladium nanoparticles for the direct synthesis of hydrogen peroxide and show that ceria can be a potentially interesting support for this reaction. However, with current methods of catalyst fabrication ceria-supported monometallic palladium catalysts have a superior performance to bimetallic gold–palladium catalysts.

The possibility is confirmed by calculation of reducing the operating temperature of a high-temperature converter-membrane system, combined with a CH4 conversion catalyst, from 800 to 700–600°C with an insignificant reduction in technical and economic indices, but with the additional possibility of expanding the choice of membrane and structural materials, including palladium alloy V-1 highly recommended in practice. Results of quantitative evaluation of high-temperature converter-membrane system parameters are in good agreement with published data for a membrane converter.

It is shown by a computing method that a high-temperature methane converter−membrane apparatus system combined with carbon monoxide conversion catalyzer is of considerable interest from the point of attaining high technoeconomic indices of special-purity hydrogen production from methane. Of added interest is the feasibility of reducing the working temperature of the membrane apparatus down to 500–600°C, which would allow broadening of the range of membrane and constructional materials, including use of the palladium alloy V-1 extensively tested in practice.

The objective of this project is to take into account the mechanical constraints formed by diffusion of hydrogen or tritium in watertight palladium alloy cathode. To know the origin of these, it was necessary to discriminating the damaging effects encountered. Effectively, hydrogen and isotope induce deformation, embrittlement, stress corrosion cracking and cathodic corrosion in different regions of cathode. Palladium can be alloyed with silver or yttrium to favourably increase diffusion and reduce these constraints. Effects of electrochemical factors, temperature, cathode structure, adsorbed transient complex of palladium and porous material support are given to estimate and to limit possible damage.

Production of super-pure hydrogen (SPH) using palladium alloy membrane is one of the major directions of hydrogen energy engineering and technology. A block diagram of a high-temperature membrane unit for production of SPH from natural gas (NG) is shown. An analysis of two variants of process regime of SPH production from NG is given. It is shown that a more effective regime is low-pressure conversion of methane and that it is advisable to create the pressure required for operation of the high-temperature membrane unit before the membrane apparatus.

Statement of problem Surface roughness and irregularities can affect the fit of a restoration. It is unknown whether different investment techniques have an effect on surface roughness and irregularities of gold palladium alloy castings. Purpose The purpose of this study was to evaluate the surface roughness and irregularities of gold palladium alloy castings obtained using different investment techniques. Material and methods Forty disk-shaped wax patterns were prepared and divided into 4 groups. A phosphate-bonded, carbon-free investment was used for the investment procedures. Twenty specimens were invested using a vacuum mixer, while the remainder were invested using a vacuum mixer and investor. The specimens in both broad categories were divided evenly to set in 2 different conditions of pressure. Half were left to set under atmospheric pressure for 1 hour, while the rest were placed in a compression chamber under a pressure of 3 bars for 24 minutes, then allowed to bench set for another 36 minutes. A profilometer was used to evaluate the surface roughness (μm) of the castings. The specimens were also studied under x10 magnification for surface irregularities. Two-way ANOVA was used to examine the relationships among surface roughness, investing, and pressure (α=.05). Logistic regression was used to explore the relationships among surface irregularities, investing, and pressure. Results Two-way ANOVA for surface roughness did not reveal any statistically significant differences. However, there was a trend for the specimens set under atmospheric pressure to present lower values of surface roughness than the specimens set under positive pressure ( P =.095). The logistic regression for surface irregularities showed a highly significant impact of pressure. The odds of any surface irregularities for specimens under atmospheric pressure were 9.12 times higher than the odds for specimens under positive pressure ( P =.016). Conclusions Within the limitations of this study, the results suggest that specimens set under atmospheric pressure are much more likely to present surface irregularities than specimens set under positive pressure. The use of pressure can help produce castings with fewer surface irregularities. (J Prosthet Dent 2008;99:282–286)

In a search for electrocatalysts based on other metals with comparable attributes to very scarce and expensive Pt, we studied the kinetics of the oxygen reduction reaction (ORR) on carbon-supported Pd3Fe alloy nanoparticles in HClO4 and NaOH solutions. In acid solution, the electrocatalyst's activity for the ORR is slightly higher than that of commercial Pt/C. The reaction kinetics involves predominantly a four-electron reduction with the first charge-transfer step being the rate-determining one. The synthesis of a Pd overlayer on the Pd3Fe alloy's surface at elevated temperatures is due to strong segregation effects. The major cause of this electrocatalyst's high activity appears to be the downshifting of the d-band center of Pd overlayer, resulting in a weaker interaction between the oxygen-containing species and the Pd surface. We demonstrated a further enhancement of the ORR kinetics with a Pt monolayer-covered Pd3Fe/C electrocatalyst. In HClO4 solution, the mass-specific activity of Pt/Pd3Fe/C was about five times higher than that of commercial Pt/C, surpassing the Pt/Pd/C. In situ XANES data indicate that this elevated ORR activity may be due to the decreased formation of PtOH, and weaker oxygen adsorption on Pt/Pd3Fe/C.

Hydrogen permeation measurements were carried out by using an Ag 23 wt%-Pd alloy membrane of 20 μ m thickness at temperatures from 773 to 873 K. Contrary to some reported results, hydrogen permeation flux was not affected by the co-existence of H 2 O up to 9.5% at 873 and 773 K under non-pressurized conditions. Further addition of CO 2 up to 27.9%, CH 4 up to 6.8%, CO up to 4.6% did not reduce the permeation flux. Similarly, permeation flux was not affected in a pressurized system with H 2 O up to 63%, 5% of CO with 30% of H 2 O , 20% of CH 4 with 15% of H 2 O , under 0.29 MPa pressurization at 873 K. From the hydrogen partial pressure dependence of the permeation flux, the rate determining step was concluded to be the bulk diffusion of H in the membrane under the abovementioned conditions.

The remarks of Zoltowski [P. Zoltowski, J. Electroanal. Chem., Remarks on “Determination of hydrogen absorption isotherm and diffusion coefficient in Pd 81 Pt 19 alloy” [F. Vigier et al., J. Electroanal. Chem. 588 (2006) 32]] refer to hydrogen electrosorption isotherm and the diffusion coefficient of hydrogen DH in Pd 81 Pt 19 alloy. However, they do not contain any quantitative analysis of data being the subject of criticism. Discussion presented below shows that in some points we do not agree and in others there was no difference in our views.

Die Abscheidung von Metallen und Legierungen in Mikrostrukturen erfordert meist eine Schichtdicke groser als 100 μm, die der Strukturhohe entspricht. Fur die Nutzung von Edelmetallen in Mikrosystemen ist die Abscheidung von spannungsarmen, rissfreien, porenfreien und duktilen Schichten notwendig. Da die kommerziell abgeschiedenen Edelmetallschichten nur bis etwa 10 μm qualitatsgerecht abgeschieden werden konnen, sind geeignete Zusatze und Variation der Abscheidungsbedingungen erforderlich, um mikrosystemtaugliche Elektrolyte zu entwickeln. Charakterisierung der Schichteigenschaften, Parameter der Abscheidungstechnologie und Anwendungsbeispiele werden aufgefuhrt. Erste Ergebnisse werden vorgestellt und diskutiert. Deposition of Thick Palladium and Palladium Alloy Layers for Microsystems Technology Layers of metals and alloys deposited in microstructures usually require to be thicker than the 100 μm which is the approximate height of the structure. The deposited form of noble metals used in microsystems must be non-stressed, ductile and free of cracks and pores. As the thickness of layers deposited from commercial noble metal electrolytes will rarely exceed 10 μm without loss of quality, developing an electrolyte system suitable for microsystems involves finding appropriate additives and deposition parameters. Details are given of deposit characterisation, the parameters of the deposition technology and some practical examples. Initial results are presented and discussed.

Objectives To test the wear of enamel against Yttria Tetragonal Zirconia Polycrystals (Y-TZP) in comparison to the wear of enamel against a noble white high Palladium alloy. Methods A total of 20 specimens were used, 10 of Y-TZP and 10 of High Palladium alloy, both were subjected to 202,800 contacts against an enamel rod 2 × 2 mm in cross section under a mean load of 475.04 g leading to a mean force of 4.66 N in a Wilson Wear Machine. The specimens were kept in Dulbecco's phosphate buffered saline at a pH of 7 and the enamel rods were measured before and after the experiment for loss of enamel height (mm). Results The mean wear caused by the Y-TZP and the High Palladium alloy tested was 0.0912 mm, and 0.0113 mm respectively. This difference was statistically significant (p = 0.012 (p Significance It is recommended that Y-TZP is not to be used to form the occlusal surfaces of indirect restorations due to its high abrasive potential with respect to dental enamel.

Annealed Pd exhibits supersaturation of the dilute phase before the hydride phase forms and this is characterized here by measurements of both |Δ H H | and equilibrium p H 2 . Dilute phase |Δ H H | and p H 2 values were determined for annealed Pd for both absorption and desorption of H 2 and the |Δ H H | were the same for both and the dilute phase H 2 isotherms were also the same, i.e., absorption/desorption was reversible. Pd, which has a high dislocation density, however, does not exhibit supersaturation, and its |Δ H H | values are a continuous function of H/Pd in contrast to annealed Pd where there is a discontinuity at the phase boundary. In addition, absorption/desorption of H 2 is irreversible for this “cycled” Pd. The same phenomena were examined for several substitutional fcc Pd–Mn alloys; supersaturation was also observed for the three alloys: X Mn = 0.01, 0.05 and 0.075.

Palladium and palladium-alloy catalysts cathode have shown a high degree of tolerance to ethanol during the ORR in an acid medium. In particular, it was shown that the onset potential for the ORR in the presence of 0.5M C2H5OH decreases by only 33 mV and 18 mV on palladium and palladium-cobalt catalysts, respectively. This decrease in the onset potential due to the presence of ethanol on the Pd-based catalysts is more than ten times lower than those observed on Pt electrodes (513 mV). On the other hand, the palladium-based catalysts do not show any peak current attributed to the electro-oxidation of ethanol, whereas the Pt-based catalyst exhibited a high peak current related to the oxidation of ethanol. The high activity of Pd and Pd-Co catalysts for the ORR, as well as their high level of tolerance to the ethanol make them suitable candidates for Direct Ethanol Fuel Cell applications.

We show that the nonmonotonic discrete (“hopping”) structure evolution takes place in nonequilibrium Pd-based alloys after hydrogen charging. It can be explained by assuming the thermodynamic potential to be of multivalley form. The states of the system corresponding to these valley minima are long-lived states. The system hops between the long-lived states during the structural evolution due to the cooperative migration of hydrogen and vacancies between matrix and defect regions. The experimental results show that such jumps can cause the lattice period to increase or decrease.

Metadislocations are novel structural defects firstly observed in the complex metallic alloy ξ′-Al–Pd–Mn. We present a transmission electron microscopy study on metadislocation reactions and networks. It is shown that metadislocations can dissociate into partials, which leads to a decrease of the elastic line energy. Connected groups of metadislocations can assume large and complex network structures with large total Burgers vectors. However, the local elastic strain at the individual metadislocation cores as well as the fault-plane energies remain small. By this mechanism, effective large Burgers vectors, contributing massively to plastic strain, can be distributed over a large portion of the material.

In the present study, the microstructure of substitutional-deposited Pd-Cu film was investigated. Results show that the composition of Pd-Cu substitutional-deposited film was Cu-16~18 at%Pd. High resolution TEM image and XRD measurements results shows that the Pd-Cu film consist of Cu and intermetallic compound (Cu3Pd). Cu3Pd intermetallic compound was existed at as-deposited film. The morphology of initial deposited Pd-Cu film was affected by crystallographic structure of Cu substrate.

The residual stress (RS) profile state of a palladium alloy sample, used in dentistry applications, has been determined by various diffraction techniques. An additional aim of this work was to improve different experimental methods dedicated to such RS evaluation, demonstrating that the X-ray, neutron and high-energy synchrotron X-ray diffraction (HESXRD) techniques are complementary when employed in different zones of the sample.

This review highlights various aspects of current palladium membrane research and serves as a comprehensive bibliography covering palladium membrane preparation methods and applications. There are many promising uses for palladium membranes, although widespread use of the available technologies is constrained primarily by the high cost of palladium, lack of durability due to hydrogen embrittlement, and susceptibility to fouling. Various researchers in the field are tackling these problems and fabricating thinner palladium alloy composite membranes that better withstand contaminantion and thermal cycling. What has been accomplished to address these issues and the directions presently being explored are discussed.

The influence of temperature and gas composition on hydrogen isotope separation factors of membrane cascade with reflux ratio of 0.9998 and different palladium alloy membranes were studied. Separation factors for H-D mixture with different palladium alloy membranes varies from 1.31 to 1.42 at different temperatures, and for H-D-T mixture with Pd-8.6%Y alloy membrane, the factors are 1.2 to 2.0 at different temperatures. The results suggest advantages of operating the cell at high temperature because the higher permeation rate and separation factor at high temperature will lead to a great decrease in the separation stages and membrane area of a separation unit.

The effects of chloride (Cl−) concentration, fluoride (F−) concentration, pH, temperature, and weldments on the corrosion behavior of Ti-0.15%Pd (Ti Grade 7, UNS R52400) were examined. It ...

In order to improve the stability to high hydrogen concentrations, of hybrid suspended gate field effect transistors (HSGFETs) with thin palladium films as sensitive layer, Pd-Ni and Pd-Ag alloys h ...

The development of solutions for palladium alloy electrodeposition is described outlining the problems of solution chemistry involved. The discussion is focused on the solution formulation for Pd-F...

Usually, shear or tensile tests are used to assess bond strengths between resin and metal. In this study, a cleavage test, the Double Cantilever Beam test, was performed to measure the adherence energy in air and in water between a 4-META resin, and five alloys (palladium, palladium-silver, gold, cobalt-chromium and nickel-chromium alloys) whose surfaces have been treated by sandblasting only or by two methods of silica coating (Silicoater MD, Rocatec) or by painting with a primer (V-Primer). Results showed that, after storage in water, it is difficult to divide the studied alloys into a dental base alloys group and a noble alloys group. Therefore, the silica coating has significantly limited the propagation of fissures in water. Higher values of adherence energy were recorded with the Rocatec system except with the palladium alloy which must be treated with the Silicoater MD system. The treatment with V-Primer was sensitive to hydrolytic attack.

The penetration depths of the hydride phases at 298 K and 6.8 kbar of gaseous hydrogen have been determined for cylindrical samples of Ni and Pd–Ni alloys, consisting of equal or more than 94 at.% of nickel. For PdxNi1−x ( x = 0.04 , 0.06) alloys, a linear dependence between thickness of the hydride ring and the wire radius has been found. The analogous function for Ni–1% Pd and Ni–1.94% Pd exhibits a parabolic course, revealing limitation in penetration depths. The maximum penetration depth of nickel hydride is about 50 μm. The general trend in the maximal penetration depths is that an increase of Pd concentration causes an increase of the maximal penetration depth.

Statement of problem. There is insufficient information regarding the adaptation of abutments to implants. Purpose. This study assessed the adaptation of premachined, cast, and laboratory modified premachined abutments to implants at two sites: abutment/implant interface and screw to screw seat. Material and methods. Six combinations of abutments and implants were studied: CeraOne abutments joined to Nobel Biocare implants; STR (Implant Innovations Inc.) abutments joined to 3I implants; Cast UCLA (3I) abutments subjected to porcelain firing cyclesand joined to 3I implants; Cast UCLA abutments subjected to porcelain firing cycles and joined to Nobel Biocare implants; UCLA premachined abutments cast with gold palladium alloy and subjected to porcelain firing cycles (later joined to 3I implants); and UCLA premachined abutments joined to 3I implants. Each group contained five assemblies. Results. The adaptation of abutments to implants was closer and the amounts of contact larger for assemblies with premachined and laboratory modified premachined abutments than for those with cast abutments. Conclusion. The finishing of custom-made abutments requires further refinement. (J Prosthet Dent 1998;80:184-92.)

The Pd 70 Ag 30 alloy nanoparticles were heated in air at 250–450 °C. During heating, segregation of Ag to the surface driven by its lower surface energy competes with the oxidation of Pd. At 250 °C, selective oxidation of Pd occurred preferentially, and the formation of large free Ag crystallites was observed. As temperature increased, oxidation of Pd became more intensive and dominating, which attracted more Pd to the surface for reaction, resulting in fewer and smaller free Ag particles on the surface.

This feature describes a unique method of manufacturing hydrogen separation membranes. It involves creating a palladium–silver layer on a substrate with a polished surface, then removing and transferring it to a membrane support. This novel technique produces highly selective thin layers with a high hydrogen flux, making their use for hydrogen separation economically attractive.

Bimetallic gold/palladium alloy nanoclusters are found to be efficient catalysts in the Ullmann coupling of chloroarenes in aqueous media at low temperatures.