bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compact Thermosyphon Cooling System For High Heat Flux Servers: Validation Of Thermosyphon Simulation Code Considering New Test Data
Authors: Haynau Rémy , Marcinichen Jackson B. , Amalfi Raffaele L. , Cataldo Filippo , Thome John R. 
Published: November 2021

Abstract
Passive, gravity-driven thermosyphons represent a step-change in technology towards the goal of greatly reducing PUE (Power Usage Effectiveness) of datacenters by replacing energy hungry fans of air-cooling approach with a highly-reliable solution able to dissipate the rising heat loads demanded in a cost-effective manner. The European Union has launched a zero carbon-footprint target for datacenters by the timeline of 2030, which would include new standards for implementing green solutions. In the present study, a newly updated version of the general thermosyphon simulation code previously presented at InterPACK 2019 and InterPACK 2020 is considered. To facilitate the industrial transition to thermosyphon cooling technology, with its intrinsic complex flow phenomena, the availability of a general-use, widely validated design tool that handles both air-cooled and liquid-cooled types of thermosyphons is of paramount importance. The solver must be able to analyze and design thermosyphon-based cooling systems with high accuracy and handle the numerous geometric singularities in the working fluid’s flow path, besides that of the secondary coolant. Therefore, a new extensive validation of the thermosyphon simulation solver is performed and presented here versus experimental data gathered for a compact liquid-cooled thermosyphon design, which is being considered for the cooling of high-performance servers. The new experimental database has been gathered to be able to characterize the effect of filling ratio, heat load, secondary coolant temperature and mass flow rate on the cooling performance, using R1234ze(E) as a low GWP (Global Warming Potential) working fluid. This compact design has experimentally demonstrated high performance, maintaining the pseudo chip’s temperature lower than 45°C for evaporator footprint heat fluxes up to 18W/cm2. The comparison shows that the solver is able to accurately predict thermosyphon thermal-hydraulic performance, and based on this prediction, characterize the internal flow rate generated by the thermosyphon, which is key to correctly estimate the maximum heat removal capability.
Nonlocal Damage Modeling of Solder Joint Failure Under Thermomechanical Cyclic Loading
Authors: Maniar Youssef , Kabakchiev Alexander , Kuczynska Marta , Bazrafshan Masoomeh , Binkele Peter , Schmauder Siegfried 
Published: November 2021

Abstract
The increasing electrified mobility poses a challenge on reliability prediction of automotive electronics, especially when safety systems are concerned. The use of finite element simulation for accurate end-of-life prediction of automotive electronic devices under harsh environmental loading condition is getting increasingly significant. In particular, solder interconnection failure is in focus when subjected to thermomechanical loads. During cyclic loading, the initial deformation behavior and subsequent solder degradation can be modeled within finite element simulations using material damage coupled deformation models. Such models employ the calculation of an internal damage state variable at integration point level as functions of time, temperature and governing stress-strain state.
In this work, a thermodynamic consistent implicit nonlocal damage formulation is presented. This modeling approach allows absolute end-of-life prediction of different solder joint geometries under thermomechanical cyclic loading within finite element simulations. The presented nonlocal damage model consists of damage evolution with strain and stress state dependencies, such as stress multiaxiality. Furthermore, a numerical de-localization algorithm is proposed, in order to avoid instability of damage evolution caused by finite element mesh dependency. Finally, the advantages and implications of the nonlocal damage approach are discussed based on simulations of damage evolution in multiple solder joints of a QFN48 package under combined cyclic thermal and mechanical 4-point bending loading.
Characterization of High-Density Aircraft Electronic and Thermal Management Systems
Authors: Kasitz Joshua , Huitink David 
Published: November 2021

Abstract
As aircrafts move toward electrification with the research and development of hybrid-electric powertrains, the focus has begun to shift to the reliability challenges of electronic devices subject to flight. Electronic components in aircraft applications are subject to two main sources of failure inducing stresses: the thermomechanical stresses that develop due to unequal coefficients of thermal expansion of different materials used in the components, and the stresses developing due to shocks and vibrations during flight as well as landing and takeoff. While the challenge of dealing with CTE mismatches is applicable to electronic devices in general, the ambient conditions surrounding the aircraft in flight, combined with weight and space constrains add significant logistical issues to any cooling mechanism. This paper will focus on the environmental influence on the thermal dissipation profile that will ultimately lead to CTE failures. The push toward more-electric-aircraft (MEA) increases the need to further advance the power and versatility of electronic cooling systems to adequately manage high density power modules, which until recently were not highly incorporated in aviation systems. Environmental conditions will play a large role in the design space and limitations of potential cooling solutions and will dictate the effectiveness of current thermal management systems. In arising scenarios where high-density electronics cannot be contained within a pressurized and temperature-controlled cabin, drastic pressure and temperature swings, facilitated by the external environment, will lead to an extra source of fluctuating stress on the cooling system. This is likely to be a prevalent factor in hybrid-electric and all-electric powertrains as requiring environmental controlled spaces for major components could be limited. This can easily be seen in current attempts to examine and redesign local cooling systems for electric motors in aviation. Representing just one of the major cooling requirements on an electric aircraft, motor cooling systems demonstrate the universal cooling problems limiting all aspects of the powertrains system. This paper aims to define the impact of the changing environment, through a flight profile of an aircraft, on high density electronic cooling systems by assessing the potential system stressors that significantly impact performance, efficiency, and reliability of the cooling systems. It will also utilize local cooling efforts for motors to relate the general problems to applicable design considerations that must be understood to further the performance capability of the overall propulsion system.
Numerical Modeling of Continuous Dynamic Recrystallization in Sn-Based Solder Connection Under Cyclic Loading
Authors: Kuczynska Marta , Becker Ulrich , Maniar Youssef , Weihe Steffen 
Published: November 2021

Abstract
The reoccurring cyclic load imposed onto soldered electronic components during their operation time leads to accumulation of inelastic strains in the structure. On a microscale level, the degree of plastic deformation is determined by the formation and annihilation of dislocations, leading to continuous refinement by creation of new grain boundaries, precipitates relocation and growth. This microstructure rearrangement, triggered by an increasing amount of inelastic deformation, is defined as dynamic recrystallization.
This work presents a macroscale modelling approach for the description of continuous dynamic recrystallization observed in Sn-based solder connections. The model used in this work describes kinetics of macroscopic gradual evolution of equivalent grain size, where the initial grain size is continuously refined with increasing accumulated inelastic strain until a saturation grain size is reached. The rate and distribution of dynamic recrystallization is further numerically modelled dependent on the effective accumulated inelastic strain and governing stress multiaxiality. A parameter study of the presented model and its employment in finite element (FE) simulation is further described. Finally, FE simulation of the grain size evolution is demonstrated on an example of a bulky sample under isothermal cyclic mechanical loading, as well as a BGA-like structure under tensile, shear and mixed mode cyclic load.
Print-Consistency and Process-Interaction for Inkjet-Printed Copper on Flexible Substrate
Authors: Lall Pradeep , Goyal Kartik , Schulze Kyle , Hill Curtis 
Published: November 2021

Abstract
Printed electronics is a fastest growing and emerging technology that have shown much potential in several industries including automotive, wearables, healthcare, and aerospace. Its applications can be found not only in flexible but also in large area electronics. The technology provides an effective and convenient method to additively deposit conductive and insulating materials on any type of substrate. Comparing with traditional manufacturing processes, which involves chemical etching, this technology also comes to be relatively environmental friendly. Despite its status, it is not without its challenges. Starting from the material being compatible in the printer equipment to the point of achieving fine resolutions, and with excellent properties are some of the challenges that printed electronics face. Among the myriad of printing technologies such as Aerosol Jet, micro-dispensing, gravure printing, screen printing, Inkjet printing, Inkjet has gained much attention due to its low-cost, low material consumption, and roll-to-roll capability for mass manufacturing. The technology has been widely used in home and office, but recently gained interest in printed electronics in a research and development setting. Conductive materials used in Inkjet printing generally comprises of metal Nanoparticles that need to be thermally sintered for it to be conductive. The preferred metal of choice has been mostly silver due to its excellent electrical properties and ease in sintering. However, silver comes to be expensive than its counterpart copper. Since copper is prone to oxidation, much focus has been given towards photonic sintering that involves sudden burst of pulsed light at certain energy to sinter the copper Nanoparticles. With this technique, only the printed material gets sintered in a matter of seconds without having a great impact on its substrate, due to which it is also preferred in low temperature applications. With all the knowledge, there is still a large gap in the process side with copper where it is important to look how the print process affects the resolution of the print along with the effect of post-print processes on electrical and mechanical properties. In this paper, a copper Inkjet ink is utilized for understanding the effect of Inkjet print parameters on the ejected droplet and its resolution. Post-print process is also quantified using a photonic sintering equipment for excellent electrical and mechanical properties. To demonstrate the complete process, commercial-off-the-shelf components will also be mounted on the additively printed pads via Inkjet. Statistically, control charting technique will be utilized to understand the capability of the Inkjet process.
Development of Multi-Layer Circuitry Using Electrically Conductive Adhesive and Low-Temperature Solder Material for Surface-Mount Component Attachment
Authors: Lall Pradeep , Narangaparambil Jinesh , Miller Scott 
Published: November 2021

Abstract
The increased versatility in the design and manufacturing of components in low volumes, as well as the shorter time between design and prototype, has increased interest in the field of additively printed electronics. The ability to directly print on a variety of substrates, whether rigid, flexible, or conformable, provides several benefits over conventional electronics fabrication methods. Furthermore, the growing complexity of flexible electronics necessitates the development of multilayered circuits similar to traditional PCBs to decrease the volumetric and gravimetric effect of the underlying electronics. Using z-axis interconnections with dielectric materials, which may allow or prevent the connection between two layers, is one method of reaching several layers of circuits. In this paper, a working multilayer circuitry test vehicle is designed and additively printed using the direct-write method. The circuit model involves conductive and dielectric ink printing, as well as passive and active component attachments using an electrically conductive adhesive (ECA) and low-temperature solder (LTS). The study also shows details about the process of developing dielectric printing parameters for microvias for multilayer z-axis interconnections.
Effect of Lamination Parameters and Mechanical Folding on SOH Degradation of Li-ion Battery Subjected to Accelerated Life Testing
Authors: Lall Pradeep , Soni Ved , Narangaparambil Jinesh , Miller Scott 
Published: November 2021

Abstract
The growing interest in the flexible field of electronics has provided impetus to incorporation of electronic components such as resistors, capacitors, LEDs, sensors, etc. into flexible circuits. Power sources are another significant component of a majority of electronic circuits which need to be integrated in flexible circuits so as to push the bounds of the wearable technology. One way to do this is by using a laminated film to laminate ultra-thin pouch batteries and then bind them to a flexible substrate. During the lamination process, these batteries are exposed to higher temperatures (above 100 °C), albeit for a short period of time, which can result in damage to the battery’s internals. In this study, a Li-ion pouch cell has been laminated using a hot roller lamination process with different conditions of lamination speed and temperature. The laminated batteries have then been subjected to accelerated life testing in presence and absence of static and dynamic mechanical folding so as to investigate the effect of folding on the laminated batteries. Further, the SOH degradation of the tested batteries is computed and has been incorporated in a regression model so as to study the effect of lamination parameters.
Challenging the dipolar paradigm for Proterozoic Earth
Authors: Sears* James W. 
Published: November 2021

ABSTRACT
A robust, geology-based Proterozoic continental assembly places the northern and eastern margins of the Siberian craton against the southwestern margins of Laurentia in a tight, spoon-in-spoon conjugate fit. The proposed assembly began to break apart in late Neoproterozoic and early Paleozoic time. Siberia then drifted clockwise along the Laurussian margin on coast-parallel transforms until suturing with Europe in late Permian time. The proposed drift path is permitted by a geocentric axial dipole (GAD) magnetic field from Silurian to Permian time. However, the Proterozoic reconstruction itself is not permitted by GAD. Rather, site-mean paleomagnetic data plotted on the reconstruction suggest a multipolar Proterozoic dynamo dominated by a quadrupole. The field may have resembled that of present-day Neptune, where, in the absence of a large solid inner core, a quadrupolar magnetic field may be generated within a thin spherical shell near the core-mantle boundary. The quadrupole may have dominated Earth’s geomagnetic field until early Paleozoic time, when the field became erratic and transitioned to a dipole, which overwhelmed the weaker quadrupole. The dipole then established a strong magnetosphere, effectively shielding Earth from ultraviolet-B (UV-B) radiation and making the planet habitable for Cambrian fauna.
Magmatism, migrating topography, and the transition from Sevier shortening to Basin and Range extension, western United States
Authors: Lundstern* Jens-Erik , Miller Elizabeth L. 
Published: November 2021

ABSTRACTThe paleogeographic evolution of the western U.S. Great Basin from the Late Cretaceous to the Cenozoic is critical to understanding how the North American Cordillera at this latitude transitioned from Mesozoic shortening to Cenozoic extension. According to a widely applied model, Cenozoic extension was driven by collapse of elevated crust supported by crustal thicknesses that were potentially double the present ~30–35 km. This model is difficult to reconcile with more recent estimates of moderate regional extension (≤50%) and the discovery that most high-angle, Basin and Range faults slipped rapidly ca. 17 Ma, tens of millions of years after crustal thickening occurred. Here, we integrated new and existing geochronology and geologic mapping in the Elko area of northeast Nevada, one of the few places in the Great Basin with substantial exposures of Paleogene strata. We improved the age control for strata that have been targeted for studies of regional paleoelevation and paleoclimate across this critical time span. In addition, a regional compilation of the ages of material within a network of middle Cenozoic paleodrainages that developed across the Great Basin shows that the age of basal paleovalley fill decreases southward roughly synchronous with voluminous ignimbrite flareup volcanism that swept south across the region ca. 45–20 Ma. Integrating these data sets with the regional record of faulting, sedimentation, erosion, and magmatism, we suggest that volcanism was accompanied by an elevation increase that disrupted drainage systems and shifted the continental divide east into central Nevada from its Late Cretaceous location along the Sierra Nevada arc. The north-south Eocene–Oligocene drainage divide defined by mapping of paleovalleys may thus have evolved as a dynamic feature that propagated southward with magmatism. Despite some local faulting, the northern Great Basin became a vast, elevated volcanic tableland that persisted until dissection by Basin and Range faulting that began ca. 21–17 Ma. Based on this more detailed geologic framework, it is unlikely that Basin and Range extension was driven by Cretaceous crustal overthickening; rather, preexisting crustal structure was just one of several factors that that led to Basin and Range faulting after ca. 17 Ma—in addition to thermal weakening of the crust associated with Cenozoic magmatism, thermally supported elevation, and changing boundary conditions. Because these causal factors evolved long after crustal thickening ended, during final removal and fragmentation of the shallowly subducting Farallon slab, they are compatible with normal-thickness (~45–50 km) crust beneath the Great Basin prior to extension and do not require development of a strongly elevated, Altiplano-like region during Mesozoic shortening.
Permanent pacemaker implantation after On-X surgical aortic valve replacement: SWEDEHEART observational study
Authors: Dalén Magnus , Persson Michael , Glaser Natalie , Sartipy Ulrik 
Published: November 2021

ObjectiveBioprosthetic aortic valves with an extended subannular component, such as transcatheter valves, exert increased compression on the cardiac conduction system and increase the risk for permanent pacemaker implantation. It is unknown if the On-X mechanical prosthetic valve, which has an elongated subannular valve housing, increases the risk of permanent pacemaker implantation following aortic valve replacement.DesignObservational nationwide cohort study.SettingSwedish population-based study.ParticipantsAll patients aged 18–65 years who underwent primary mechanical aortic valve replacement in Sweden between 2005 and 2018. We used the Swedish Web system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies register and other Swedish national health-data registers.ExposurePatients implanted with an On-X valve versus patients implanted with other bileaflet mechanical valves.Primary and secondary outcome measuresPrimary outcome measure was permanent pacemaker implantation within 30 days of surgery.ResultsA total of 2602 patients were included, and 581 patients received an On-X valve and 2021 patients received a St Jude Masters/Regent (n=945) or Carbomedics Reduced valve (n=1076). In the total study population, 115 (4.4%) permanent pacemaker implantations were performed within 30 days after aortic valve replacement. In the propensity score matched population, there was no significant difference in the rate of permanent pacemaker implantation in the On-X group compared with the control group: 3.6% (95% CI: 2.4% to 5.5%) vs 4.0% (95% CI: 2.7% to 5.9%), p=0.877.ConclusionsThe On-X prosthetic heart valve was associated with a similarly low risk for permanent pacemaker implantation after aortic valve replacement compared with other conventional bileaflet mechanical valves. The On-X elongated subannular valve housing does not interfere with the cardiac conduction system.
Unravelling data for rapid evidence-based response to COVID-19: a summary of the unCoVer protocol
Authors: Peñalvo José L. , Mertens Elly , Ademović Enisa , Akgun Seval , Baltazar Ana Lúcia , Buonfrate Dora , Čoklo Miran , Devleesschauwer Brecht , Diaz Valencia Paula Andrea , Fernandes João C. , Gómez Enrique Javier , Hynds Paul , Kabir Zubair , Klein Jörn , Kostoulas Polychronis , Llanos Jiménez Lucía , Lotrean Lucia Maria , Majdan Marek , Menasalvas Ernestina , Nguewa Paul , Oh In-Hwan , O’Sullivan Georgie , Pereira David M. , Reina Ortiz Miguel , Riva Silvia , Soriano Gloria , Soriano Joan B. , Spilki Fernando , Tamang Mary Elizabeth , Trofor Antigona Carmen , Vaillant Michel , Van Ierssel Sabrina , Vuković Jakov , Castellano José M. 
Published: November 2021

IntroductionunCoVer—Unravelling data for rapid evidence-based response to COVID-19—is a Horizon 2020-funded network of 29 partners from 18 countries capable of collecting and using real-world data (RWD) derived from the response and provision of care to patients with COVID-19 by health systems across Europe and elsewhere. unCoVer aims to exploit the full potential of this information to rapidly address clinical and epidemiological research questions arising from the evolving pandemic.Methods and analysisFrom the onset of the COVID-19 pandemic, partners are gathering RWD from electronic health records currently including information from over 22 000 hospitalised patients with COVID-19, and national surveillance and screening data, and registries with over 1 900 000 COVID-19 cases across Europe, with continuous updates. These heterogeneous datasets will be described, harmonised and integrated into a multi-user data repository operated through Opal-DataSHIELD, an interoperable open-source server application. Federated data analyses, without sharing or disclosing any individual-level data, will be performed with the objective to reveal patients’ baseline characteristics, biomarkers, determinants of COVID-19 prognosis, safety and effectiveness of treatments, and potential strategies against COVID-19, as well as epidemiological patterns. These analyses will complement evidence from efficacy/safety clinical trials, where vulnerable, more complex/heterogeneous populations and those most at risk of severe COVID-19 are often excluded.Ethics and disseminationAfter strict ethical considerations, databases will be available through a federated data analysis platform that allows processing of available COVID-19 RWD without disclosing identification information to analysts and limiting output to data aggregates. Dissemination of unCoVer’s activities will be related to the access and use of dissimilar RWD, as well as the results generated by the pooled analyses. Dissemination will include training and educational activities, scientific publications and conference communications.