scholarly journals High-Temperature Electronics Packaging for Simulated Venus Condition

2020 ◽  
Vol 17 (2) ◽  
pp. 59-66
Author(s):  
Ardalan Nasiri ◽  
Simon S. Ang ◽  
Tom Cannon ◽  
Errol V. Porter ◽  
Kaoru Uema Porter ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Alumina Ceramic ◽  
Resistance Change ◽  
Wire Bond ◽  
Die Attach ◽  
Before And After ◽  
Mechanical Durability ◽  
Bond Wire ◽  
Carbon Dioxide Co2 ◽  
Simulator Test

Abstract An electronic packaging technology that survives the simulated Venusian surface temperature of 465°C and 96 bar pressure in carbon dioxide (CO2) and nitrogen environments, without the corrosive trace gases, was developed. Alumina ceramic substrates and gold conductors on alumina were evaluated for electrical and mechanical performance. The most promising die-attach materials are thick-film gold and alumina-based ceramic pastes. Alumina, sapphire, silicon, and silicon carbide dies were attached to the alumina substrates using these die-attach materials and exposed to 96 bar pressure in a CO2 environment at 465°C for 244 h. The ceramic die-attach material showed consistent shear strengths before and after the test. An alumina ceramic encapsulation material was also evaluated for thermomechanical stability. The devices on the packaging substrates were encapsulated by a ceramic encapsulation with no significant increase in cracks and voids after the Venusian simulator test. Wire pull strength tests were conducted on the gold bond wire to evaluate mechanical durability before and after the Venusian simulator exposure. The average gold bond wire pull strengths before and after exposure were 5.78 g-F and 4 g-F for 1-mil gold bond wires, respectively, meeting the minimum MIL-STD-885 2011.9 standard. The overall wire bond daisy chain resistance change was .47% after the Venus simulator test, indicating a promising wire bond integrity. A titanium package was fabricated to house the ceramic packaging substrate and a two-level metalized feedthrough was fabricated to provide electrical interfaces to the package.

Indentation Tests for Sintered Silver in Die-Attach Interconnection After Thermal Cycling

2021 ◽  
Author(s):  
Fei Qin ◽  
Shuai Zhao ◽  
Yanwei Dai ◽  
Lingyun Liu ◽  
Tong An ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Silver Layer ◽  
Thermal Cycles ◽  
Nano Indentation ◽  
Die Attach ◽  
Indentation Tests ◽  
Sintered Silver

Abstract Thermo-mechanical reliability assessment for sintered silver is a crucial issue as sintered silver is a promising candidate of die-attachment materials for power devices. In this paper, the nano-indentation tests are performed for sintered silver in typical die-attach interconnection under different thermal cycles. Based on thermal cycling test, the Young's modulus and hardness of sintered silver layer have been presented. It is found that the Young's modulus and hardness of sintered silver layer changes slightly although the microstructure of sintered silver also presents some variations. The stress and strain curves for different thermal cycling tests for sintered silver based on reverse analysis of nano-indentation are also given. The results show that the elastoplastic constitutive equations change significantly after thermal cycling tests, and the yielding stress decreases remarkably after 70 thermal cycles. The experimental investigation also show that the cracking behaviors of sintered silver depends on its geometry characteristics, which implies that the possible optimization of sintered silver layer could enhance its thermo-mechanical performance.

scholarly journals Application of Waterborne Acrylic and Solvent-Borne Polyester Coatings on Plasma-Treated Fir (Abies alba M.) Wood

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 370
Author(s):  
Hadi Gholamiyan ◽  
Behnam Gholampoor ◽  
Reza Hosseinpourpia
Keyword(s):  
Plasma Treatment ◽  
Treated Wood ◽  
Abies Alba ◽  
Untreated Wood ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Accelerated Weathering ◽  
Water Contact ◽  
Before And After ◽  
Carbon Dioxide Co2

This research investigates the effect of plasma treatment with air, nitrogen (N2), and carbon dioxide (CO2) gases on the performance of waterborne (acrylic) and solvent-borne (polyester) coated fir (Abies alba M.) wood samples. The properties of the plasma-coated samples were analyzed before and after exposure to accelerated weathering and compared with those of untreated and solely treated ones. According to pull-off testing, the coating adhesion of the wood samples was considerably improved by plasma treatment, and obvious differences were observed between different plasma gases. The effect was more pronounced after the weathering test. Similar results were obtained for the abrasion resistance of the samples. The water contact angle measurement illustrated more hydrophilic character in the solely plasma-treated wood in comparison with the untreated wood. The application of coatings, however, strongly improved its hydrophobic character. The performances of waterborne and solvent-borne coatings on plasma-treated wood were comparable, although slightly better values were obtained by the waterborne system. Our results exhibit the positive effect of plasma treatment on coating performances and the increased weather resistance of the waterborne and solvent-borne coating systems on plasma-treated wood.

scholarly journals MECHANICAL CHARACTERIZATION OF PA 12 AND HDPE PIPES BEFORE AND AFTER AGING IN WATER AT TWO DIFFERENT TEMPERATURES

2021 ◽  
Vol 9 (1) ◽  
pp. 248-256
Author(s):  
J.A. dos Santos ◽  
R.C. Tucunduva ◽  
J.R.M. D’Almeida
Keyword(s):  
High Density Polyethylene ◽  
Mechanical Performance ◽  
High Density ◽  
Effect Of Temperature ◽  
Polyamide 12 ◽  
Polyethylene Pipes ◽  
Before And After ◽  
Different Temperatures ◽  
Deterioration Process ◽  
Combined Action

Polymer pipes are being widely used by many industrial segments. Although not affected by corrosion, the mechanical performance of these pipes can be reduced due to exposure to temperature, UV radiation and by contact with various fluids. Depending on the deterioration process, embrittlement or plasticization may occur, and the service life of the pipe can be severely reduced. In this work, the combined action of temperature and water upon the mechanical performance of polyamide 12 and high-density polyethylene pipes is evaluated. Destructive and non-destructive techniques were used and the performance of both materials was compared. Both polymers were platicized by the effect of water. However, for high density polyethylene the effect of temperature was more relevant than for polyamide. This behavior was attributed to the dependence of the free volume with the markedly different glass transition temperature of the polymers and the temperatures of testing.

scholarly journals Research on Mechanical Performance & Behaviour of Geopolymer Concrete Subjected to Elevated Temperatures

2019 ◽  
Vol 8 (2S8) ◽  
pp. 883-887
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Geopolymer Concrete ◽  
Sem Images ◽  
Before And After ◽  
Alkaline Conditions ◽  
Compressive Strength Of Concrete

The investigative studies on mechanical performance & behaviour, of Geopolymer Concrete (GPC) before and after the exposure to elevated temperatures (of 200 0 C -1000 0 C with an increment of 100 0 C). Indicate that the GPC Specimens Exhibited better Compressive strength at higher temperatures than that of those made by regular OPC Concrete with M30 Grade. The chronological changes in the geopolymeric structure upon exposure to these temperatures and their reflections on the thermal behaviour have also been explored. The SEM images indicate GPC produced by fly ash , metakaolin and silica fume, under alkaline conditions form Mineral binders that are not only non-flammable and but are also non-combustible resins and binders. Further the Observations drawn disclose that the mass and compressive strength of concrete gets reduced with increase in temperatures.

scholarly journals Desain Sistem Functional Test RFID Chips Array untuk Proses Manufaktur Smart Card pada TFME Politeknik Negeri Batam

2020 ◽  
Vol 4 (2) ◽  
pp. 44-48
Author(s):  
Nanta Fakih Prebianto ◽  
Nur Sakinah Asaad ◽  
Riki Ria
Keyword(s):  
Smart Card ◽  
Functional Test ◽  
Rfid Reader ◽  
Wire Bond ◽  
Die Attach

Proses pengembangan dan produksi smart card dilakukan pada Teaching Factory Manufacturing of Electronics (TFME) Politeknik Negeri Batam. Pada proses produksi smart card perlu dikembangkan sistem pengujian sample untuk memastikan hasil wiring dan proses die attach berhasil yang ditandai dengan komunikasi antara chip dan RFID reader (13,56 MHz). Pendekatan yang dilakukan adalah merancang sistem uji fungsi RFID otomatis dengan memanfaatkan pergerakan tiga axis dan mini probe yang melekat pada pad sambungan wire bond dan die. Metode yang digunakan pada penelitian ini terdiri dari perancangan mekanik, perancangan elektrik, perancangan perangkat lunak, dan pengujian sistem. Resistansi probe RFID memiliki resistansi 1,8 Ohm. Pergerakan setiap axis menggunakan motor stepper yang dikopling dengan ulir linear T8 2pitch 4star. Torsi yang terukur pada axis x, y, dan z adalah 4.64 N.mm, 59,54 N.mm, dan 10,72 N.mm pada saat stepper bergerak maju.

Severe diastolic dysfunction with preserved energy conversion efficiency after countershock

1997 ◽  
Vol 273 (2) ◽  
pp. H583-H592 ◽  
Author(s):  
S. Yasuda ◽  
T. Shishido ◽  
Y. Goto
Keyword(s):  
Diastolic Dysfunction ◽  
Mechanical Performance ◽  
Diastolic Pressure ◽  
Mechanical Energy ◽  
Systolic Pressure ◽  
Myocardial Edema ◽  
Energy Conversion Efficiency ◽  
Left Ventricular ◽  
Stunned Myocardium ◽  
Before And After

The left ventricular (LV) mechanical performance and the LV myocardial oxygen consumption (VO2)-to-pressure-volume area (PVA; LV total mechanical energy index) relationship were measured in isovolumic contraction of isolated blood-perfused dog hearts before and after direct current (DC) countershocks. At a constant LV volume, DC shocks increased LV end-diastolic pressure progressively and strikingly with the progression of myocardial edema and a marked prolongation of the time constant of LV pressure decay. In contrast, DC shocks changed neither the slope of the LV end-systolic pressure-volume relationship nor the contractile efficiency (the slope of the Vo2-PVA relationship). The oxygen cost of contractility (the slope of the relationship between PVA-independent VO2 and LV contractility) increased 27% after DC shocks. However, the magnitude of this change was considerably smaller than that previously reported in postischemic stunned myocardium (123%), suggesting that the adverse effect of DC shocks on the energy cost of excitation-contraction coupling is relatively minor. Thus, despite the severe diastolic dysfunction, DC shocks do not substantially impair either the efficiency of cross-bridge cycling or calcium cycling. Myocardial interstitial edema is more likely a potential mechanism of diastolic dysfunction after DC shocks.

scholarly journals Damage Constitutive Model and Mechanical Performance Deterioration of Concrete under Sulfate Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Peng Liu ◽  
Ying Chen ◽  
Zhiwu Yu ◽  
Zhaohui Lu
Keyword(s):  
Mechanical Properties ◽  
Bearing Capacity ◽  
Elasticity Modulus ◽  
Mechanical Performance ◽  
Sulfate Solution ◽  
Concrete Surface ◽  
Ultimate Bearing Capacity ◽  
Stress Strain ◽  
Before And After ◽  
Relationship Model

The effects of erosion mode, erosion age, and concentration of sulfate solution on mechanical properties of concrete were investigated. The dimensionless relationship model of the stress-strain of concrete on the basis of randomness was proposed. The variation of the elasticity modulus and Poisson’s ratio of the concrete surface attacked by sulfate was studied, and a novel method of using a superficial parameter to characterize the performance change of the concrete surface was recommended. The results showed that the dimensionless relationship model of stress-strain of concrete could be used to represent the variations of mechanical properties of concrete. The differences of load-displacement of concrete before and after sulfate attack were reflected as the change of curve’s slope and ultimate bearing capacity, and the slope of a straight section of the lateral and longitudinal strain curves of concrete surface also varied. The increment rates of ultimate bearing capacity of concrete attacked by 1% and saturated sulfate solution were about 30% and 10%, respectively. However, the decreasing ratio of the ultimate bearing capacity of concrete attacked by saturated sulfate solution was approximately 25%. The damage factor of the elasticity modulus of the concrete surface of C20 and C40 was 0.185 and −0.19, respectively. The obtained results could provide a support for investigating the variations of stress-strain relationship and mechanical performance of concrete under a sulfate environment.

scholarly journals The Sensitivity of an Electro-Thermal Photovoltaic DC–DC Converter Model to the Temperature Dependence of the Electrical Variables for Reliability Analyses

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2865 ◽  
Author(s):  
Wieland Van De Sande ◽  
Simon Ravyts ◽  
Omid Alavi ◽  
Philippe Nivelle ◽  
Johan Driesen ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Thermal Model ◽  
Computation Time ◽  
Capital Expenditures ◽  
Plastic Energy ◽  
Main Research ◽  
Die Attach ◽  
Bond Wire ◽  
Energy Dissipated ◽  
Method Model

The operational expenditures of solar energy are gaining attention because of the continuous decrease of the capital expenditures. This creates a demand for more reliable systems to further decrease the costs. Increased reliability is often ensured by iterative use of design for reliability. The number of iterations that can take place strongly depends on the computational efficiency of this methodology. The main research objective is to quantify the influence of the temperature dependence of the electrical variables used in the electro-thermal model on the reliability and the computation time. The influence on the reliability is evaluated by using a 2-D finite elements method model of the MOSFET and calculating the plastic energy dissipation density in the die-attach and the bond wire. The trade-off between computation time of the electro-thermal model in PLECS (4.3, Plexim, Zurich, Switzerland) and generated plastic energy accuracy obtained in COMSOL (5.3, COMSOL Inc., Burlington, MA, USA) is reported when excluding a certain temperature dependence. The results indicate that the temperature dependence of the input and output capacitors causes no change in the plastic energy dissipated in the MOSFET but does introduce the largest increase in computation time. However, not including the temperature dependence of the MOSFET itself generates the largest difference in plastic energy of 10% as the losses in the die are underestimated.

Positive inotropic effect of Streptococcus faecalis in isolated cardiac muscle

1994 ◽  
Vol 267 (6) ◽  
pp. H2450-H2461 ◽  
Author(s):  
I. E. Schoemaker ◽  
S. U. Sys ◽  
L. J. Andries ◽  
J. M. Meyers ◽  
S. R. Pattyn ◽  
...  
Keyword(s):  
Cardiac Muscle ◽  
Positive Inotropic Effect ◽  
Mechanical Performance ◽  
Bacterial Colonization ◽  
Ringer Solution ◽  
Inotropic Effect ◽  
Maximal Velocity ◽  
Acute Effects ◽  
Before And After ◽  
Isometric Twitch

Infective endocarditis is caused by bacterial colonization of the endocardium. Because endocardium modulates mechanical performance of subjacent myocardium, we studied acute effects of bacteria on isolated cardiac muscle and on the functional role of the endocardium. Bacteria, grown in broth at 37 degrees C, were added at increasing concentrations (10(2) to 10(6) bacteria/ml) to cat papillary muscles in Krebs-Ringer solution (1.25 mM Ca2+, 35 degrees C). The endocardial surface was damaged by exposing muscles to a stream of dry air for 30 s. Streptococcus (Enterococcus) faecalis induced significant increases in total peak isometric twitch tension (TT) and maximal velocity of unloaded shortening (Vmax) and significant decreases in time to TT (TtTT) and time to half isometric twitch tension decline (RT 1/2), both before and after removal of endocardial endothelium. This response could also be elicited with bacterial filtrate, after boiling the filtrate or after extracting the polysaccharides from it with KIO4. Increasing Ca2+ concentrations progressively reduced the response to the filtrate. Propranolol slightly, although not significantly, diminished the effects on TT and Vmax while abolishing the effects on TtTT and on RT 1/2. By contrast, Streptococcus bovis and Staphylococcus aureus did not affect TT or Vmax but induced a slight but significant decrease in TtTT at the highest concentration of bacteria. Accordingly, the filtrate of Strep. faecalis induces a positive inotropic effect. The active component is neither a protein nor a polysaccharide, and its effect may be partly beta-adrenoceptor mediated. Strep. bovis and Staph. aureus have negligible acute effects on contractility.

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