Comparative evaluation of corrosion effects between nanocrystalline silver alloy and tradition gold stacks using spring probe contacts

2019 ◽  
Author(s):  
Vinay Budhraja ◽  
Jarvis Stirn ◽  
Eric Hallstrom ◽  
Brian Lutz ◽  
Michael Brennan

Although silver is evaluated as an alternative of gold, it is more prone to tarnishing, oxidization and corrosion. Recent advancements in nano materials research resulted in a nanocrystalline silver alloy which has several advantages like high hardness, thermal stability, non-coarsen with age, hence a viable solution for connector applications. In this work, the performance of nanocrystalline silver alloy against corrosion was studied. Two different set of spring probes were electroplated on inner and outer regions and tested using force deflection resistance (FDR), life cycle test (LCT), SEM, EDS and X-Ray CT scan. First set of spring probes were electroplated with nanocrystalline silver alloy, nanocrystalline Ni-W, Ni sulfamate and Ni strike with thicknesses of 2.4 µm, 1.8 µm, 2.0 µm and 0.5 µm respectively. Second set of spring probes were electroplated with Gold, Ni sulfamate and Ni strike with thicknesses of 0.9 µm 1.9 µm and 0.5 µm respectively. The body of spring probes was made up of copper alloy. This work reports the changes in electrical, mechanical and material properties of nanocrystalline silver alloy and gold stacks after reliability operations like humidity test for 24 hours and 96 hours, porosity test for 60 mins and salt-fog test for 24 hours.

Author(s):  
W. Brünger

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.


Author(s):  
P. J. Melnick ◽  
J. W. Cha ◽  
E. Samouhos

Spontaneous mammary tumors in females of a high tumor strain of C3H mice were cut into small fragments that were Implanted into the subcutaneous tissue of the back of males of the same strain, where they grew as transplantable tumors. When about Cm. In diameter daily fractional radiation was begun, applied to the tumors, the rest of the body being shielded by a lead shield. Two groups were treated with 150 and 200 r X-ray dally, of half value layer 0.6mm. copper; a third group was treated with 500 r cobalt radiation dally. The primary purpose was to examine the enzyme changes during radiation, with histochemlcal technics.


Alloy Digest ◽  
1958 ◽  
Vol 7 (3) ◽  

Abstract NICKEL SILVER, 55-18 is a spring quality nickel silver alloy having high resistance to corrosion and tarnish. It is used primarily for springs and electrical resistances. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-61. Producer or source: Copper alloy mills.


Alloy Digest ◽  
1976 ◽  
Vol 25 (1) ◽  

Abstract NJZ Alloy No. 45 is a zinc-copper alloy characterized by high hardness and strength, good ductility and high stiffness. It work hardens easily. Among its many applications are hardware, sporting-equipment components, cable wrappings and watch cases. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep and fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: Zn-25. Producer or source: New Jersey Zinc Company.


2019 ◽  
Author(s):  
Martin Greta

BACKGROUND Tuberculosis is a widespread and in many cases a fatal, infectious disease caused by many strains of mycobacterium complex usually mycobacterium tuberculosis. It can affect any part of the body but mainly the lungs hence called pulmonary tuberculosis. Tuberculosis in children has been less of a public health priority in the recent years despite the fact that TB has been a major cause of childhood morbidity and mortality worldwide with difficulties in diagnosis. Data on trends of childhood TB is rarely in published literature hence need for this research which will help in publishing OBJECTIVE To establish the trends in TB among children aged 1-12 years and its management over a period of five years from 2011- 2015 at Arthur Davison children’s hospital in Ndola and also to determine the proportion of TB in these children and to establish the age group most affected by TB over the period of five years and lastly to assess the proportion of TB and HIV as a co-morbidity METHODS The study reviewed all records that were registered in the MOH TB register at ADH from 2011 to 2015 coming up with a total number of 483 TB records and these records had satisfied the inclusion and exclusion criteria. The data capturing tool was used to collect the data. RESULTS : This study determined the trends of TB in children aged 1 to 12 over the five years period from a total of 483 reviewed paediatric TB cases , its proportion in these children, the age range most affected by TB and lastly assessed TB and HIV as a co-morbidity at Arthur Davison Children’s hospital. It revealed that the trends were decreasing and that out of 483 TB patient, the majority 157(32.5%) of the TB patients were seen in the year 2011, followed by 129(26.7%), 84(17.4%), 57(11.8%) and 56(11.6%) representing the year 2012, 2013, 2014 and 2015 respectively. Findings on the age range most affected are that the majority 282(58.4%) of the TB patients were aged (5-12) years old while 201(41.6%) were aged between (1-5) years old. Therefore, the age range most affected by TB was between (5-12) years. The TB proportion results showed that Out of 483, the majority 467(96.7%) of the TB patient type were newly diagnosed, followed by 13(2.7%), 2(.4%) and the rest 1(.2%) that were Relapse, Trans-in and Treatment resumed respectively. And that many 467(96.7%) of TB condition types were PTB while 16(3.3%) were EPTB. Furthermore, the majority of 463(95.9%) were diagnosed by X-ray while 20(4.1%) were diagnosed by smear microscopy. And lastly In terms of HIV as a co-morbidity, the majority 175(36.2%) of the TB patients were HIV positive, followed by 173(35.8%) that were HIV negative while the rest 135(28%) of the TB patients were not tested for HIV CONCLUSIONS This study reports that the trends of TB in children aged 1-12 years have been decreasing from 2015 to 2011 .And the age range most affected was found to have been 5-12 years and the proportion of TB cases were mostly newly diagnosed and the diagnosis was made by use x-ray and lastly the large proportion of TB patients had tested positive for HIV as a co-morbidity. Therefore efforts should be made to sustain this decreasing trend of childhood TB.


2008 ◽  
Vol 396-398 ◽  
pp. 569-572
Author(s):  
Fumio Watari ◽  
Shigeaki Abe ◽  
I.D. Rosca ◽  
Atsuro Yokoyama ◽  
Motohiro Uo ◽  
...  

Nanoparticles may invade directly into the internal body through the respiratory or digestive system and diffuse inside body. The behavior of nanoparticles in the internal body is also essential to comprehend for the realization of DDS. Thus it is necessary to reveal the internal dynamics for the proper treatments and biomedical applications of nanoparticles. In the present study the plural methods with different principles such as X-ray scanning analytical microscope (XSAM), MRI and Fluorescent microscopy were applied to enable the observation of the internal diffusion of micro/nanoparticles in the (1) whole body level, (2) inner organ level and (3) tissue and intracellular level. Chemical analysis was also done by ICP-AES for organs and compared with the results of XSAM mapping.


Author(s):  
F. Nicastro ◽  
J. Kaastra ◽  
C. Argiroffi ◽  
E. Behar ◽  
S. Bianchi ◽  
...  

AbstractMetals form an essential part of the Universe at all scales. Without metals we would not exist, and the Universe would look completely different. Metals are primarily produced via nuclear processes in stars, and spread out through winds or explosions, which pollute the surrounding space. The wanderings of metals in-and-out of astronomical objects are crucial in determining their own evolution and thus that of the Universe as a whole. Detecting metals and assessing their relative and absolute abundances and energetics can thus be used to trace the evolution of these cosmic components. The scope of this paper is to highlight the most important open astrophysical problems that will be central in the next decades and for which a deep understanding of the Universe’s wandering metals, their physical and kinematical states, and their chemical composition represents the only viable solution. The majority of these studies can only be efficiently performed through High Resolution Spectroscopy in the soft X-ray band.


2021 ◽  
Vol 11 (6) ◽  
pp. 2723
Author(s):  
Fatih Uysal ◽  
Fırat Hardalaç ◽  
Ozan Peker ◽  
Tolga Tolunay ◽  
Nil Tokgöz

Fractures occur in the shoulder area, which has a wider range of motion than other joints in the body, for various reasons. To diagnose these fractures, data gathered from X-radiation (X-ray), magnetic resonance imaging (MRI), or computed tomography (CT) are used. This study aims to help physicians by classifying shoulder images taken from X-ray devices as fracture/non-fracture with artificial intelligence. For this purpose, the performances of 26 deep learning-based pre-trained models in the detection of shoulder fractures were evaluated on the musculoskeletal radiographs (MURA) dataset, and two ensemble learning models (EL1 and EL2) were developed. The pre-trained models used are ResNet, ResNeXt, DenseNet, VGG, Inception, MobileNet, and their spinal fully connected (Spinal FC) versions. In the EL1 and EL2 models developed using pre-trained models with the best performance, test accuracy was 0.8455, 0.8472, Cohen’s kappa was 0.6907, 0.6942 and the area that was related with fracture class under the receiver operating characteristic (ROC) curve (AUC) was 0.8862, 0.8695. As a result of 28 different classifications in total, the highest test accuracy and Cohen’s kappa values were obtained in the EL2 model, and the highest AUC value was obtained in the EL1 model.


2021 ◽  
Vol 13 (5) ◽  
Author(s):  
Viktória Mozgai ◽  
Bernadett Bajnóczi ◽  
Zoltán May ◽  
Zsolt Mráv

AbstractThis study details the non-destructive chemical analysis of composite silver objects (ewers, situlas, amphora and casket) from one of the most significant late Roman finds, the Seuso Treasure. The Seuso Treasure consists of fourteen large silver vessels that were made in the fourth–early fifth centuries AD and used for dining during festive banquets and for washing and beautification. The measurements were systematically performed along a pre-designed grid at several points using handheld X-ray fluorescence analysis. The results demonstrate that all the objects were made from high-quality silver (above 90 wt% Ag), with the exception of the base of the Geometric Ewer B. Copper was added intentionally to improve the mechanical properties of soft silver. The gold and lead content of the objects shows constant values (less than 1 wt% Au and Pb). The chemical composition as well as the Bi/Pb ratio suggests that the parts of the composite objects were manufactured from different silver ingots. The ewers were constructed in two ways: (i) the base and the body were made separately, or (ii) the ewer was raised from a single silver sheet. The composite objects were assembled using three methods: (i) mechanical attachment; (ii) low-temperature, lead-tin soft solders; or (iii) high-temperature, copper-silver hard solders. Additionally, two types of gilding were revealed by the XRF analysis, one with remnants of mercury, i.e. fire-gilding, and another type without remnants of mercury, presumably diffusion bonding.


Author(s):  
C. Newton ◽  
W. T. W. Potts

Magnesium/chlorine and sulphur/chlorine ratios have been measured in the body fluids of some planktonic organisms by x-ray emission analysis of frozen hydrated specimens in a scanning electron microscope. Homarus vulgaris (Anthropoda: Decapoda) larvae excluded Mg2+ and SO42-ions from the haemolymph, but to a lesser extent than does the adult lobster. Bipinnaria larvae of Asterias (Echinodermata) excluded Mg2+ and SO42-ions from the coelomic fluid. Obelia medusae excluded Mg2+ and SO42-ions from the mesogloea but concentrate them in the gastrovascular system. The high concentration of sulphate in the gastrovascular fluid of medusae has been confirmed by rhodizonate titration in Cyanea and Rhizostoma jellyfish. Some implications of magnesium and sulphate regulation are discussed.


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