bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic Hybrids for Circuit Assemblies – Initial environmental testing of a low cost alternative to ceramic substrate based assemblies
Authors: Wickham Martin , Clayton Kate , Robador Ana , Thorogood Christine 
Published: May 2018

Abstract
There are an increasing number of electronics applications in aerospace, automotive, shale/gas and power management, which are required to operate at or above 200 °C. Organic matrix reinforced substrates such as polyimide, have maximum operating temperatures in the region of 175 °C. Reliable operation of electronics at temperatures higher than this requires a combination of performance improvements in components, interconnects and substrates. Ceramic based substrate options are based on alumina substrates with printed inks fired at ~ 600 °C and can be costly, heavy and prone to mechanical damage. Printed circuit board (PCB) options are restricted to lower working temperatures of the organic resins and degradation of their conductive copper tracks through oxidation. This paper highlights earlier work undertaken by the authors and partners to understand the deficiencies of copper-clad PCB technology and details work to develop a low cost alternative to ceramic substrate based assemblies. The authors have investigated replacing the alumina substrates with high temperature engineering thermoplastics such as PEEK. The high temperature fired inks conventionally used in hybrid circuit manufacture have been replaced with screen-printable silicone based ink systems curing at 250 °C. The specially developed electrically conductive and dielectric inks were utilised to produce a multilayer system demonstrator with high temperature compatible components attached using a high temperature conductive adhesive. Such an assembly system has the potential to benefit from reductions in substrate cost and assembly weight. Energy cost associated with manufacture are significantly reduced. In addition the organic substrate is easier to machine and form into complex shapes and offers the possibility of integrating thermal management solutions. Environmental testing has been undertaken to determine the suitability of the system to operate for extended periods at 250 °C and the results of the electrical and mechanical performance for continuous ageing of test assemblies at 250 °C will be given.
Influence of Initial Shear Strength on Time-to-Failure of Copper (Cu) Wire Bonds in Thermal Aging Condition
Authors: Manoharan Subramani , Patel Chandradip , Hunter Stevan , McCluskey Patrick 
Published: May 2018

Abstract
Copper (Cu) wire bond is used in a majority of microelectronic devices but has not been fully accepted by all industries due to potential reliability issues. Good quality bond is believed to provide high reliability. Shear strength and intermetallic (IMC) coverage are being used as indicators, however there is no developed model. High shear strength is a result of large IMC coverage laterally under the ball, but the reliability of the bond is also related to IMC longitudinal growth (thickness). This work involves studying effect of shear strength on reliability of a variety of experimental Cu ball bonds by performing temperature aging experiments on test devices, in QFN packages. The ball bonds are made by altering ultrasonic power and time to obtain different IMC coverage. All test packages are monitored for resistance change at specific intervals by performing four point resistance measurement. Resistance increase is analyzed with initial shear strength to determine whether “good quality” bonds always lead to high reliability.
Environmentally Hardening IC Die Previously Assembled in Plastic Packages through Die Removal, Bond Pad Replating and Reassembly into Hermetic Packages
Authors: Beebout Charlie , Spory Erick M. 
Published: May 2018

ABSTRACT
Many integrated circuits (ICs) will operate well above their maximum rated temperature of +70°C or +125°C, but are often not packaged appropriately to reliably endure temperatures above +150C. Specifically, the original gold or copper bonds on the aluminum die bond pads are prone to Kirkendall or Horsting voiding, particularly at temperatures greater than +150°C. Also the mold compounds used in plastic packaging for IC assembly can degrade at these elevated temperatures. In some cases, commercial demand for higher temperature reliability can justify a separate offering of ICs assembled in hermetic, ceramic packages from the original component manufacturer (OCM). However, in most cases, the market demand is deemed insufficient.
Global Circuit Innovations (GCI) has developed a high-yielding process, which can remove a semiconductor die (i.e., computer chip) from a plastic package, remove the original bond wires and/or ball bonds, plate the aluminum die bond pads with Electroless Nickel, Electroless Palladium, and Immersion Gold (ENEPIG), and then reassemble the now improved semiconductor die into a hermetic, ceramic package. Device Extraction, ENEPIG die bond pad plating and Repackaging (DEER) provides an improved die bond pad surface such that works well with either gold or aluminum bond wires in applications up to +250°C without mechanical or electrical connectivity degradation. GCI routinely exposes sample devices to +250°C bakes with 100% post bake yields so as to continuously ensure that any device processed with the DEER technology will reliably perform in high-temperature environments.
Although the oil and gas industry has already expressed significant interest in the DEER process, with excellent lifetest and production application results demonstrating dramatically increased component lifetimes at elevated temperatures, this technology can also be leveraged for any application exposing ICs to harsh environments. Not only is the high-temperature reliability dramatically increased, but also the new hermetic, ceramic package protects the IC from a variety of elements and environments (i.e., corrosives and moisture).
Novel solder-mesh interconnection design for power module applications
Authors: Lis Adrian , Tatsumi Hiroaki , Matsuda Tomoki , Sano Tomokazu , Kashiba Yoshihiro , Hirose Akio 
Published: May 2018

Abstract
This study introduces a novel concept that uses composite structures of thin metallic meshes and Sn3.0Ag0.5Cu (SAC305) solder alloys to interconnect semiconductor chips to DBC substrates. The feasibility was proven by bonding Cu-to-Cu substrates. The averaged shear strength was measured as 44.1, 44.7 and 51.4 MPa for samples bonded with SAC305 (reference), Ni mesh/SAC305 and Cu mesh/SAC305 composites, respectively. The solder-mesh joints revealed a specific fracture behavior where crack propagation occurred partly within the solder and partly at the solder-mesh interface. Microstructural analyses confirmed that the metallic meshes were bonded by the formation of intermetallic compounds (IMC) while almost no (larger) defects were found. The solder-mesh concept was subsequently applied on Si-to-DBC assemblies. A very good resistance of Cu mesh/SAC305 composite joints against cyclic temperature between 80 and 200 °C was observed when the bonded area only reduced by 4.2 % after 8000 cycles. Thermal finite element (FE) simulations indicated that in particular Cu mesh/SAC305 composites can significantly reduce the thermal resistance of the interconnections which is equivalent to a better heat dissipation through the bonding layer. Thus, solder-mesh composite joints seem to be an attractive solution for high-temperature applications up to 200 °C.
Performance Test Results of a Precision Data Acquisition and Control Platform for 200°C+ High Temperature Environments
Authors: Watson Jeff , Pachchigar Maithil , Bannatyne Ross , Merritt Clay , Conrad Christopher , Smollinger Glenn , Drack Earle 
Published: May 2018

Abstract
In recent years there has been an increasing selection of commercially available electronic components specified for very high temperature (200C+) operation, driven by the needs of harsh-environment applications such as oil and gas exploration/production, aerospace, heavy industrial, and automotive. However, there remains a significant technical challenge to integrate these components into reliable, high performance systems. We previously presented a complete reference design of a precision multichannel sensor data acquisition and control system rated to 200C, including characterized hardware, firmware, and software. The design is based around low power 16 bit SAR ADCs and an ARM® Cortex®-M0 processor and is optimized for high resolution and high throughput measurements while maintaining low power and a small footprint. In this paper we present the test results of this system over temperature. The reference platform is available off the shelf, including hardware design files, processor firmware source code, and PC software for data logging and display, providing engineers a rapid development tool for prototyping and a faster path to production for complex harsh-environment applications.
Lifetime and Failure Modes of High Temperature SOI Products
Authors: Maxwell Derek , Soares Marshall , Coreless Matt 
Published: May 2018

Abstract
RelChip has performed life test studies on its RAM and has shown that Silicon On Insulator (SOI) processing with Aluminum-Tungsten metal traces can operate for over 4000 hours at 350°C and do not fail due to electromigration. Three parts were randomly selected and functionally tested at the extreme temperature using accelerated testing (HAST). The parts were pulled periodically for in-depth testing and examination. Test results indicate failures are due to device failures, and not electromigration.
US Geothermal Funding Outlook (Reducing Cost Barriers for HT SOI Reservoir Monitoring Systems)
Authors: Normann Randy A. 
Published: May 2018

ABSTRACT
The presentation of this paper will discuss the expected funding levels from the US Dept. of Energy available for geothermal research. However, at the time this paper submitted for publication at HiTEC, those funding levels have not been publically released.
This paper examines the use of Arduino systems for developing geothermal well monitoring systems and logging tools. The Arduino is a low cost, public domain micro processing system commonly used for teaching machine programming at the high school level. These systems enjoy open domain support and many levels of self-help books. The Arduino enjoys worldwide acceptance for teaching high school students how to build and program robotic machines. The Arduino system is so popular, Ebay.com lists 2,244 “Arduino Kits”. Kits for learning robotics, operating 3D printers, monitoring sensors and other general applications in electronics. This paper examines using the Arduino system for scientific measurement purposes. Two application examples are given: 275°C well monitoring tool interface and a simple, very low cost temperature logging tool. This paper highlights two new Arduino Shield for scientific measurements: a 22Bit ADC and a 12Bit DAC programmable power supply for powering high temperature downhole tools.
Characterizing biospheric carbon balance using CO2 observations from the OCO-2 satellite
Authors: Miller Scot M. , Michalak Anna M. , Yadav Vineet , Tadić Jovan M. 
Published: May 2018

Abstract. NASA's Orbiting Carbon Observatory 2 (OCO-2) satellite launched in summer of
2014. Its observations could allow scientists to constrain CO2 fluxes
across regions or continents that were previously difficult to monitor. This
study explores an initial step toward that goal; we evaluate the extent to
which current OCO-2 observations can detect patterns in biospheric CO2
fluxes and constrain monthly CO2 budgets. Our goal is to guide top-down,
inverse modeling studies and identify areas for future improvement. We find
that uncertainties and biases in the individual OCO-2 observations are
comparable to the atmospheric signal from biospheric fluxes, particularly
during Northern Hemisphere winter when biospheric fluxes are small. A series
of top-down experiments indicate how these errors affect our ability to
constrain monthly biospheric CO2 budgets. We are able to constrain budgets
for between two and four global regions using OCO-2 observations, depending
on the month, and we can constrain CO2 budgets at the regional level
(i.e., smaller than seven global biomes) in only a handful of cases (16 %
of all regions and months). The potential of the OCO-2 observations, however,
is greater than these results might imply. A set of synthetic data
experiments suggests that retrieval errors have a salient effect. Advances in
retrieval algorithms and to a lesser extent atmospheric transport modeling
will improve the results. In the interim, top-down studies that use current
satellite observations are best-equipped to constrain the biospheric carbon
balance across only continental or hemispheric regions.
Intercontinental transport of biomass burning pollutants over the Mediterranean Basin during the summer 2014 ChArMEx-GLAM airborne campaign
Authors: Brocchi Vanessa , Krysztofiak Gisèle , Catoire Valéry , Guth Jonathan , Marécal Virginie , Zbinden Régina , El Amraoui Laaziz , Dulac François , Ricaud Philippe 
Published: May 2018

Abstract. The Gradient in Longitude of Atmospheric constituents above the Mediterranean
basin (GLAM) campaign was set up in August 2014, as part of the
Chemistry and Aerosol Mediterranean Experiment (ChArMEx) project. This campaign
aimed to study the chemical variability of gaseous pollutants and aerosols
in the troposphere along a west–east transect above the Mediterranean Basin
(MB). In the present work, we focus on two biomass burning events detected at
5.4 and 9.7 km altitude above sea level (a.s.l.) over Sardinia (from
39∘12′ N–9∘15′ E to
35∘35′ N–12∘35′ E and at
39∘30′ N–8∘25′ E, respectively). Concentration
variations in trace gas carbon monoxide (CO), ozone (O3) and aerosols
were measured thanks to the standard instruments on board the Falcon 20
aircraft operated by the Service des Avions Français Instrumentés
pour la Recherche en Environnement (SAFIRE) and the Spectromètre
InfraRouge In situ Toute Altitude (SPIRIT) developed by LPC2E. Twenty-day
backward trajectories with Lagrangian particle dispersion model FLEXPART
(FLEXible PARTicle) help to understand the transport processes and the origin
of the emissions that contributed to this pollution detected above
Sardinia. Biomass burning emissions came (i) on 10 August from the North
American continent with air masses transported during 5 days before arriving
over the MB, and (ii) on 6 August from Siberia, with air masses travelling
during 12 days and enriched in fire emission products above Canada 5 days
before arriving over the MB. In combination with the Global Fire Assimilation
System (GFAS) inventory and the Moderate Resolution Imaging Spectroradiometer
(MODIS) satellite fire locations, FLEXPART reproduces well the contribution
of those fires to CO and aerosols enhancements under adjustments of the
injection height to 10 km in both cases and application of an amplification
factor of 2 on CO GFAS emissions for the 10 August event. The chemistry
transport model (CTM) MOCAGE is used as a complementary tool for the case of
6 August to confirm the origin of the emissions by tracing the CO global
atmospheric composition reaching the MB. For this event, both models agree on
the origin of air masses with CO concentrations simulated with MOCAGE lower
than the observed ones, likely caused by the coarse model horizontal
resolution that yields the dilution of the emissions and diffusion during
transport. In combination with wind fields, the analysis of the transport of
the air mass documented on 6 August suggests the subsidence of CO pollution
from Siberia towards North America and then a transport to the MB via fast
jet winds located at around 5.5 km in altitude. Finally, using the ratio
ΔO3 ∕ ΔCO, the plume age can be estimated and the
production of O3 during the transport of the air mass is studied using
the MOCAGE model.
Using different assumptions of aerosol mixing state and chemical composition to predict CCN concentrations based on field measurements in urban Beijing
Authors: Ren Jingye , Zhang Fang , Wang Yuying , Collins Don , Fan Xinxin , Jin Xiaoai , Xu Weiqi , Sun Yele , Cribb Maureen , Li Zhanqing 
Published: May 2018

Abstract. Understanding the impacts of aerosol chemical composition and mixing state on
cloud condensation nuclei (CCN) activity in polluted areas is crucial for
accurately predicting CCN number concentrations (NCCN). In
this study, we predict NCCN under five assumed schemes of aerosol
chemical composition and mixing state based on field measurements in Beijing
during the winter of 2016. Our results show that the best closure is achieved
with the assumption of size dependent chemical composition for which
sulfate, nitrate, secondary organic aerosols, and aged black carbon are
internally mixed with each other but externally mixed with primary organic
aerosol and fresh black carbon (external–internal size-resolved, abbreviated
as EI–SR scheme). The resulting ratios of predicted-to-measured
NCCN (RCCN_p∕m) were 0.90 – 0.98 under both clean and
polluted conditions. Assumption of an internal mixture and bulk chemical
composition (INT–BK scheme) shows good closure with RCCN_p∕m
of 1.0 –1.16 under clean conditions, implying that it is adequate for CCN
prediction in continental clean regions. On polluted days, assuming the
aerosol is internally mixed and has a chemical composition that is size
dependent (INT–SR scheme) achieves better closure than the INT–BK scheme due
to the heterogeneity and variation in particle composition at different
sizes. The improved closure achieved using the EI–SR and INT–SR assumptions
highlight the importance of measuring size-resolved chemical composition for
CCN predictions in polluted regions. NCCN is significantly
underestimated (with RCCN_p∕m of 0.66 – 0.75) when using the
schemes of external mixtures with bulk (EXT–BK scheme) or size-resolved
composition (EXT–SR scheme), implying that primary particles experience rapid
aging and physical mixing processes in urban Beijing. However, our results
show that the aerosol mixing state plays a minor role in CCN prediction when
the κorg exceeds 0.1.
Distinctive effects of allochthonous and autochthonous organic matter on CDOM spectra in a tropical lake
Authors: Brandão Luciana Pena Mello , Brighenti Ludmila Silva , Staehr Peter Anton , Asmala Eero , Massicotte Philippe , Tonetta Denise , Barbosa Francisco Antônio Rodrigues , Pujoni Diego , Bezerra-Neto José Fernandes 
Published: May 2018

Abstract. Despite the increasing understanding about differences in carbon cycling between temperate and tropical freshwater systems, our knowledge on the importance of organic matter (OM) pools on light absorption properties in tropical lakes is very scarce. We performed a factorial mesocosm experiment in a tropical lake (Minas Gerais, Brazil) to evaluate the effects of increased concentrations of allochthonous and autochthonous OM, and differences in light availability on the light absorption characteristics of chromophoric dissolved organic matter (CDOM). Autochthonous OM deriving from phytoplankton ( ∼  Chl a) was stimulated by addition of nutrients, while OM from degradation of terrestrial leaves increased allochthonous OM, and neutral shading was used to manipulate light availability. Effects of the additions and shading on DOC, Chl a, nutrients, total suspended solid concentrations (TSM) and spectral CDOM absorption were monitored every 3 days. CDOM quality was characterized by spectral indices (S250–450, S275–295, S350–450, SR and SUVA254). Effects of carbon sources and shading on the spectral CDOM absorption was investigated through principal component (PCA) and redundancy (RDA) analyses. The two different OM sources affected CDOM quality very differently and shading had minor effects on OM levels, but significant effects on OM quality, especially in combination with nutrient additions. Spectral indices (S250–450 and SR) were mostly affected by allochthonous OM addition. The PCA showed that enrichment by allochthonous carbon had a strong effect on the CDOM spectra in the range between 300 and 400 nm, while the increase in autochthonous carbon increased absorption at wavelengths below 350 nm. Our study shows that small inputs of allochthonous OM can have large effects on the spectral light absorption compared to large production of autochthonous OM, with important implications for carbon cycling in tropical lakes.
Nutrient availability and the ultimate control of the biological carbon pump in the western tropical South Pacific Ocean
Authors: Moutin Thierry , Wagener Thibaut , Caffin Mathieu , Fumenia Alain , Gimenez Audrey , Baklouti Melika , Bouruet-Aubertot Pascale , Pujo-Pay Mireille , Leblanc Karine , Lefevre Dominique , Helias Nunige Sandra , Leblond Nathalie , Grosso Olivier , de Verneil Alain 
Published: May 2018

Abstract. Surface waters (0–200 m) of the western tropical South Pacific (WTSP) were
sampled along a longitudinal 4000 km transect (OUTPACE cruise, DOI: 10.17600/15000900)
during the austral summer (stratified) period (18 February to 3 April 2015)
between the Melanesian Archipelago (MA) and the western part of the SP gyre (WGY). Two distinct areas were
considered for the MA, the western MA (WMA), and the eastern MA (EMA). The
main carbon (C), nitrogen (N), and phosphorus (P) pools and fluxes provide a
basis for the characterization of the expected trend from oligotrophy to
ultra-oligotrophy, and the building of first-order budgets at the daily and
seasonal timescales (using climatology). Sea surface chlorophyll a well reflected
the expected oligotrophic gradient with higher values obtained at WMA,
lower values at WGY, and intermediate values at EMA. As expected, the euphotic
zone depth, the deep chlorophyll maximum, and nitracline depth deepen from
west to east. Nevertheless, phosphaclines and nitraclines did not match. The
decoupling between phosphacline and nitracline depths in the MA allows for excess
P to be locally provided in the upper water by winter mixing. We found a
significant biological “soft tissue” carbon pump in the MA sustained almost
exclusively by dinitrogen (N2) fixation and essentially controlled by phosphate
availability in this iron-rich environment. The MA appears to be a net
sink for atmospheric CO2, while the WGY is in quasi-steady state. We
suggest that the necessary excess P, allowing the success of nitrogen fixers
and subsequent carbon production and export, is mainly brought to the upper
surface by local deep winter convection at an annual timescale rather than by
surface circulation. While the origin of the decoupling between phosphacline
and nitracline remains uncertain, the direct link between local P upper
water enrichment, N2 fixation, and organic carbon production and
export, offers a possible shorter timescale than previously thought between
N input by N2 fixation and carbon export. The low iron availability
in the SP gyre and P availability in the MA during the stratified period may
appear as the ultimate control of N input by N2 fixation. Because
of the huge volume of water to consider, and because the SP Ocean is the
place of intense denitrification in the east (N sink) and N2
fixation in the west (N source), precise seasonal C, N, P, and iron (Fe) budgets would
be of prime interest to understand the efficiency, at the present time and
in the future, of the oceanic biological carbon pump.