bluuebunny/crossref_metadata_2025 huggingface dataset:
Crowdsourcing Analysis of Twitter Data on Climate Change: Paid Workers vs. Volunteers
Authors: Kirilenko Andrei , Desell Travis , Kim Hany , Stepchenkova Svetlana
Published: November 2017

Web based crowdsourcing has become an important method of environmental data processing. Two alternatives are widely used today by researchers in various fields: paid data processing mediated by for-profit businesses such as Amazon’s Mechanical Turk, and volunteer data processing conducted by amateur citizen-scientists. While the first option delivers results much faster, it is not quite clear how it compares with volunteer processing in terms of quality. This study compares volunteer and paid processing of social media data originating from climate change discussions on Twitter. The same sample of Twitter messages discussing climate change was offered for processing to the volunteer workers through the Climate Tweet project, and to the paid workers through the Amazon MTurk platform. We found that paid crowdsourcing required the employment of a high redundancy data processing design to obtain quality that was comparable with volunteered processing. Among the methods applied to improve data processing accuracy, limiting the geographical locations of the paid workers appeared the most productive. Conversely, we did not find significant geographical differences in the accuracy of data processed by volunteer workers. We suggest that the main driver of the found pattern is the differences in familiarity of the paid workers with the research topic.
Discrete Sine Transform-Based Interpolation Filter for Video Compression
Authors: Kim MyungJun , Lee Yung-Lyul
Published: November 2017

Fractional pixel motion compensation in high-efficiency video coding (HEVC) uses an 8-point filter and a 7-point filter, which are based on the discrete cosine transform (DCT), for the 1/2-pixel and 1/4-pixel interpolations, respectively. In this paper, discrete sine transform (DST)-based interpolation filters (DST-IFs) are proposed for fractional pixel motion compensation in terms of coding efficiency improvement. Firstly, a performance of the DST-based interpolation filters (DST-IFs) using 8-point and 7-point filters for the 1/2-pixel and 1/4-pixel interpolations is compared with that of the DCT-based IFs (DCT-IFs) using 8-point and 7-point filters for the 1/2-pixel and 1/4-pixel interpolations, respectively, for fractional pixel motion compensation. Finally, the DST-IFs using 12-point and 11-point filters for the 1/2-pixel and 1/4-pixel interpolations, respectively, are proposed only for bi-directional motion compensation in terms of the coding efficiency. The 8-point and 7-point DST-IF methods showed average Bjøntegaard Delta (BD)-rate reductions of 0.7% and 0.3% in the random access (RA) and low delay B (LDB) configurations, respectively, in HEVC. The 12-point and 11-point DST-IF methods showed average BD-rate reductions of 1.4% and 1.2% in the RA and LDB configurations for the Luma component, respectively, in HEVC.
Multiple Attribute Decision-Making Methods Based on Normal Intuitionistic Fuzzy Interaction Aggregation Operators
Authors: Liu Peide
Published: November 2017

Normal intuitionistic fuzzy numbers (NIFNs), which combine the normal fuzzy number (NFN) with intuitionistic number, can easily express the stochastic fuzzy information existing in real decision making, and power-average (PA) operator can consider the relationships of different attributes by assigned weighting vectors which depend upon the input arguments. In this paper, we extended PA operator to process the NIFNs. Firstly, we defined some basic operational rules of NIFNs by considering the interaction operations of intuitionistic fuzzy sets (IFSs), established the distance between two NIFNs, and introduced the comparison method of NIFNs. Then, we proposed some new aggregation operators, including normal intuitionistic fuzzy weighted interaction averaging (NIFWIA) operator, normal intuitionistic fuzzy power interaction averaging (NIFPIA) operator, normal intuitionistic fuzzy weighted power interaction averaging (NIFWPIA) operator, normal intuitionistic fuzzy generalized power interaction averaging (NIFGPIA) operator, and normal intuitionistic fuzzy generalized weighted power interaction averaging (NIFGWPIA) operator, and studied some properties and some special cases of them. Based on these operators, we developed a decision approach for multiple attribute decision-making (MADM) problems with NIFNs. The significant characteristics of the proposed method are that: (1) it is easier to describe the uncertain information than the existing fuzzy sets and stochastic variables; (2) it used the interaction operations in part of IFSs which could overcome the existing weaknesses in operational rules of NIFNs; (3) it adopted PA operator which could relieve the influence of unreasonable data given by biased decision makers; and (4) it made the decision-making results more flexible and reliable because it was with generalized parameter which could be regard as the risk attitude value of decision makers. Finally, an illustrative example is given to verify its feasibility, and to compare with the existing methods.
The First Cry2Ac-Type Protein Toxic to Helicoverpa armigera: Cloning and Overexpression of Cry2ac7 Gene from SBS-BT1 Strain of Bacillus thuringiensis
Authors: Saleem Faiza , Shakoori Abdul
Published: November 2017

The Cry (crystal) proteins from Bacillus thuringiensis are known to have toxicity against a variety of insects and have been exploited to control insect pests through transgenic plants and biopesticides. B. thuringiensis SBS BT-1 carrying the cry2 genes was isolated from soil samples in Pakistan. The 2-kb full length cry2Ac gene was cloned, sequenced, and submitted to the EMBL DNA database (Accession No. AM292031). For expression analysis, Escherichia coli DH5α was transformed with the fragment sub-cloned in pET22b expression vector using NdeI and HindIII restriction sites, and later confirmed by restriction endonuclease analysis. To assess the toxicity of Cry2Ac7 protein against lepidopteran and dipteran insects, BL21 (codon plus) strain of E. coli was further transformed with the recombinant plasmid. The 65-kDa protein was expressed in the form of inclusion bodies up to 180 OD units per liter of the medium. Inclusions were washed with a buffer containing 1.5% Triton-X 100 and >90% pure Cry2Ac7 was obtained. The inclusion bodies were dissolved in 50 mM K2CO3 (pH 11.5), dialyzed, and freeze-dried. This freeze-dried protein as well as inclusion bodies were used in bioassays against larvae of Helicoverpa armigera and Musca domestica. The freeze-dried protein was toxic to H. armigera larvae with an LC50 value of 131 ng/mL. However, Cry2Ac7 produced in E. coli did not show any mortality to M. domestica larvae. This is the first report of Cry2Ac protein toxic to H. armigera.
Biology of the BKPyV: An Update
Authors: Helle Francois , Brochot Etienne , Handala Lynda , Martin Elodie , Castelain Sandrine , Francois Catherine , Duverlie Gilles
Published: November 2017

The BK virus (BKPyV) is a member of the Polyomaviridae family first isolated in 1971. BKPyV causes frequent infections during childhood and establishes persistent infections with minimal clinical implications within renal tubular cells and the urothelium. However, reactivation of BKPyV in immunocompromised individuals may cause serious complications. In particular, with the implementation of more potent immunosuppressive drugs in the last decade, BKPyV has become an emerging pathogen in kidney and bone marrow transplant recipients where it often causes associated nephropathy and haemorrhagic cystitis, respectively. Unfortunately, no specific antiviral against BKPyV has been approved yet and the only therapeutic option is a modulation of the immunosuppressive drug regimen to improve immune control though it may increase the risk of rejection. A better understanding of the BKPyV life cycle is thus needed to develop efficient treatment against this virus. In this review, we provide an update on recent advances in understanding the biology of BKPyV.
“In-Process Type” Dynamic Muskingum Model Parameter Estimation Method
Authors: Zhang Gang , Xie Tuo , Zhang Lei , Hua Xia , Wu Chen , Chen Xi , Li Fangfeng , Zhao Bin
Published: November 2017

This paper discusses the Muskingum model as a novel parameter estimation method. Sixty representative floods over the past four decades serve as research objects; a linear Muskingum model and Pigeon-inspired optimization (PIO) algorithm are used to obtain the parameters of each flood. The proposed “in-process type” dynamic parameter estimation (IP-DPE) method is used to establish the characteristic attributes set of 50 floods. The characteristic attributes set refers to a set of parameters that could describe the shape, magnitude, and duration of the flood before flood peak; they are the input, whereas parameters K and x of each flood are the output to establish a Neural Network model. Then we input flood characteristic attributes to obtain flood parameters when estimating flood parameters practically. Ten floods were used to test the parameter estimation and flood routing efficacy. The results show that the IP-DPE method can quickly identify parameters and facilitate accurate river flood forecasting.
Removal of Heavy Metals from Urban Stormwater Runoff Using Bioretention Media Mix
Authors: Wang Jianlong , Zhao Yuanling , Yang Liqiong , Tu Nannan , Xi Guangpeng , Fang Xing
Published: November 2017

Heavy metals from urban stormwater runoff are important sources of surface water pollutants. Sand, zeolite, sandy loam, and quartz-sand were separately mixed with lignin to form four bioretention media mixes for experimental study using synthetic stormwater runoff. The average removal efficiencies of four heavy metals (Cu, Zn, Cd, and Pb) by the four media mixes were all better than 97% at the optimum pH of 6.05 (ranging from 6 to 8) and the seven-day rainfall-event interval. The influence of the influent concentration and the rainfall-event interval on the removal efficiency of heavy metals by the four media mixes was not significant, but the variation of the removal efficiencies at the four-day rainfall-event interval was large. Under acidic conditions, there was a certain heavy metal dissolution in the four reactors, but the effect on the removal efficiency was minor. Heavy metals were present in the media mainly in the form of the residual fraction (>50%). The accumulation of Cu, Zn, and Cd in the surface planting-soil layer (same humus and sandy-loam mixture for all reactors) was significantly larger than the accumulation at deeper depths but not for Pb. Overall, the heavy metal removal efficiencies by the four media mixes were not significantly different, and the choice of the planting-soil layer can become the control factor of heavy metal removal.
Leprosy Reactions: Clinical and Therapeutic Profile of Patients Registered at a Dermatology Reference Center in Brazil
Authors: De Sousa Danielle Oliveira , De Oliveira Karolyne Moura Rique , Centeno Deborah Marques , Mainardi Carolina Ribeiro , Souza Jean Carlos Alves de Lima , De França Tiago Gallan , Bellesi Lucas Mendonça de Araújo , Pires Carla Andrea Avelar
Published: November 2017

Introduction: During the course of leprosy, 10 to 50% of individuals can be surprised by reaction states, which are immune system reactions of the patient to Mycobacterium leprae. Leprosy reactions constitute the main cause of nerve damage and disability caused by leprosy.

Objective:To analyze the clinical and therapeutic profile of patients with leprosy reactions registered in a Dermatology Service in the city of Belém-PA.

Methods:This is a cross-seccional, descriptive study. It was investigated through analysis of medical records, 52 patients who fit the established inclusion criteria. Data were collected in july and august 2016.

Results: It was found a predominance of men, from the metropolitan region. The clinical form most common of Leprosy was Borderline, and the leprosy reaction type 1. The most of reactions occurred right after the introduction of multidrug therapy,and more than a half of patients with type 1 reaction showed edema of limbs. Regarding the type 2, fever and general symptoms were the most common, present in all cases. The frequency of neural damage was evident, showing reduction of motor force level andloss of protective sensation.

Conclusion: Early diagnosis and appropriate therapeutic management of reactive events is critical to the prevention of disabilities.
Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. II. Planetary Systems Observed During Campaigns 1–7
Authors: Dressing Courtney D. , Vanderburg Andrew , Schlieder Joshua E. , Crossfield Ian J. M. , Knutson Heather A. , Newton Elisabeth R. , Ciardi David R. , Fulton Benjamin J. , Gonzales Erica J. , Howard Andrew W. , Isaacson Howard , Livingston John , Petigura Erik A. , Sinukoff Evan , Everett Mark , Horch Elliott , Howell Steve B.
Published: November 2017

We recently used near-infrared spectroscopy to improve the characterization of 76 low-mass stars around which K2 had detected 79 candidate transiting planets. 29 of these worlds were new discoveries that had not previously been published. We calculate the false positive probabilities that the transit-like signals are actually caused by non-planetary astrophysical phenomena and reject five new transit-like events and three previously reported events as false positives. We also statistically validate 17 planets (7 of which were previously unpublished), confirm the earlier validation of 22 planets, and announce 17 newly discovered planet candidates. Revising the properties of the associated planet candidates based on the updated host star characteristics and refitting the transit photometry, we find that our sample contains 21 planets or planet candidates with radii smaller than 1.25 R
⊕, 18 super-Earths (1.25–2 R
⊕), 21 small Neptunes (2–4 R
⊕), three large Neptunes (4–6 R
⊕), and eight giant planets (>6 R
⊕). Most of these planets are highly irradiated, but EPIC 206209135.04 (K2-72e,

), EPIC 211988320.01 (

), and EPIC 212690867.01 (

) orbit within optimistic habitable zone boundaries set by the “recent Venus” inner limit and the “early Mars” outer limit. In total, our planet sample includes eight moderately irradiated 1.5–3 R
⊕ planet candidates (F

p
 ≲ 20 F
⊕) orbiting brighter stars (Ks < 11) that are well-suited for atmospheric investigations with the Hubble, Spitzer, and/or James Webb Space Telescopes. Five validated planets orbit relatively bright stars (Kp < 12.5) and are expected to yield radial velocity semi-amplitudes of at least 2 m s−1. Accordingly, they are possible targets for radial velocity mass measurement with current facilities or the upcoming generation of red optical and near-infrared high-precision RV spectrographs.
Different Types of Ion Populations Upstream of the 2013 October 8 Interplanetary Shock
Authors: Kajdič Primož , Hietala Heli , Blanco-Cano Xóchitl
Published: November 2017

We show for the first time that different types of suprathermal ion distributions may exist upstream of a single interplanetary shock. ACE and the two ARTEMIS satellites observed a shock on 2013 October 8. The ARTEMIS P1 and P2 spacecraft first observed field-aligned ions (P1) and gyrating ions (P2) arriving from the shock. These were followed by intermediate ions and later by a diffuse population. At the location of the P2 the shock exhibited an Alfvénic Mach number of M
A = 5.7 and was marginally quasi-perpendicular (

). At P1 spacecraft the shock was weaker (M
A = 4.9) and more perpendicular (

). Consequently, the observed suprathermal ion and ultra-low-frequency wave properties were somewhat different. At P2 the ultra-low-frequency waves are more intense and extend farther upstream from the shock. The energies of field-aligned and gyrating ions in the shock rest-frame were ∼20 keV, which is much more than in the case of the stronger (M
A = 6–7) Earth’s bow shock, where they are less than 10 keV.
The Mass Growth and Stellar Ages of Galaxies: Observations versus Simulations
Authors: Hill Allison R. , Muzzin Adam , Franx Marijn , Marchesini Danilo
Published: November 2017

Using observed stellar mass functions out to z = 5, we measure the main progenitor stellar mass growth of descendant galaxies with masses of

at

using an evolving cumulative number density selection. From these mass growth histories, we are able to measure the time at which half the total stellar mass of the descendant galaxy was assembled, t

a
, which in order of decreasing mass corresponds to redshifts of

, and 0.51. We compare this to the median light-weighted stellar age t
* (

and 0.37) of a sample of low-redshift SDSS galaxies (from the literature) and find the timescales are consistent with more massive galaxies forming a higher fraction of their stars ex situ compared to lower-mass descendants. We find that both t
* and t

a
strongly correlate with mass, which is in contrast to what is found in the EAGLE hydrodynamical simulation that shows a flat relationship between t

a
and M
*. However, the semi-analytic model (SAM) of Henriques et al. is consistent with the observations in both t

a
and t
* with M
*, showing that the most recent SAMs are better able to decouple the evolution of the baryons from the dark matter in lower-mass galaxies.
Les anciens combattants irlandais de la Première Guerre mondiale
Authors: Destenay Emmanuel
Published: November 2017

Les études actuelles consacrées à l’Armée républicaine irlandaise (IRA) concluent que pendant la guerre d’indépendance (1919-1921) les républicains ciblaient délibérément les survivants des tranchées pour les punir de leur engagement auprès des Britanniques au cours de la Première Guerre mondiale. Or, en sollicitant des témoignages de rescapés, il s’avère que très peu d’entre eux imputent leurs souffrances à leur participation au premier conflit mondial. Par ailleurs, l’IRA approchait volontairement les vétérans pour leur savoir-faire militaire et les incitait à entrainer les nouvelles recrues pour défaire l’armée britannique. En ce sens, il est difficile de soutenir les thèses selon lesquelles les républicains s’acharnaient de façon systématique sur les anciens combattants de la Grande Guerre.
Apuntes para una teoría de la poesía infantil
Authors: Herrera Rojas Ramón Luis
Published: November 2017

Se caracterizan los rasgos considerados esenciales de la poesía infantil, a la luz de una visión integradora e interdisciplinar que toma en cuenta las ciencias del lenguaje y de la literatura contemporáneas. La vuelta del lenguaje hacia sí mismo en una materialidad fónico-rítmica de los significantes estimuladora de acciones lúdicas; la intertextualidad con el caudal folclórico oral; la densidad isotópica favorecedora de la coherencia textual; la narratividad dinamizadora del discurso; el predominio de lo imaginal sobre lo abstracto; la constitución frecuente de hablantes líricos infantiles, son, entre otros, factores que tienden a estimular la recepción y que caracterizan a un género literario proclive a una relación singular con la tradición y que se mueve entre tensiones resueltas ejemplarmente en la obra de muchos poetas de alta maestría creadora. Se ejemplifican dichos rasgos mediante textos de algunos de los más relevantes autores de España e Hispanoamérica.
Estrategias imitativas en las Églogas pastoriles de Pedro de Padilla: la huella de Ovidio
Authors: Pérez-Abadín Barro Soledad
Published: November 2017

Las Églogas pastoriles de Pedro de Padilla, libro bucólico de extracción virgiliana, diversifican su configuración a través del ejercicio de una imitatio compuesta, que canaliza la adopción de modelos ajenos a la tradición pastoral, entre los que figuran Ovidio, Boccaccio, Petrarca, Sannazaro, Garcilaso y Fray Luis de León, incorporados con diversas tácticas imitativas. Este artículo muestra la presencia de dos obras de Ovidio, los Remedia amoris y la Fábula de Narciso (Metamorfosis, III, vv. 339-510), ejemplos de imitación heurística, que permite adaptar la fuente al marco pastoral, sin desfigurarla. Los Remedia amoris son objeto de un tratamiento selectivo, para añadirse como elemento marginal a la historia de Silvano. La Fábula de Narciso desarrolla el mito ovidiano, mediatizada por la versión italiana de Alamanni, que también dirige las recreaciones de Hernando de Acuña y Gregorio Silvestre.
La inconclusa edición crítica de las De situ orbis explanationes in Dionysium Afrum de Pedro Juan Núñez a través de la correspondencia de Gregorio Mayans y Francisco Cerdá
Authors: Pandiella Gutiérrez Paulino
Published: November 2017

En este artículo mostramos el trabajo de Gregorio Mayans y Siscar y otros ilustrados valencianos en la recuperación de la obra de su compatriota el humanista Pedro Juan Núñez. Nos centramos en reconstruir el proyecto de edición de un texto de Núñez (De situ orbis explanationes in Dionysium Afrum) por Mayans y Francisco Cerdá Rico, tomando como fuente principal su correspondencia.
Jacinto Octavio Picón y el reto de la verosimilitud
Authors: Gutiérrez Díaz-Bernardo Esteban
Published: November 2017

La temprana adscripción al naturalismo del narrador madrileño Jacinto Octavio Picón (1852- 1923) deja en sus novelas y cuentos una extraordinaria preocupación por la verosimilitud, condición primera y principal de la narrativa según los planteamientos de Émile Zola, y ello no obstante el influjo que sobre el autor ejerce la nueva novela novelesca, también de procedencia francesa, a partir de los primeros años noventa. A lo largo de toda su producción, Picón presentará un cuidado extremo en no sucumbir a la inverosimilitud o a aquello que aun basándose en lo real pudiera parecer inverosímil: la advertencia de la aparición de personajes idealistas o soñadores y de otros aspectos novelescos del relato, la justificación de lo casual o azaroso, el rigor absoluto en el punto de vista…, constituyen algunas de las facetas que fundamentan la práctica narrativa del autor madrileño.
Espacio de reflejos. Las autosemblanzas de El Liberal, 1908-1909
Authors: Fraga María Jesús
Published: November 2017

Treinta y seis jóvenes poetas hispanos publican sus autosemblanzas poéticas en el diario El Liberal en un corto espacio de tiempo (1908 y 1909). En este trabajo se analiza el perfil mayoritario del grupo, así como las diferentes propuestas con que los autores se aproximan al yo: desde el retrato canónico o biográfico hasta la divagación metafísica más hermética, sin olvidar otros métodos introspectivos que determinan su identificación con la poética, el paisaje, el ambiente familiar, etc.
Ficción y autobiografía en la construcción del sujeto lírico. Dos visiones contemporáneas del intimismo
Authors: Moreno Pedrosa Joaquín
Published: November 2017

Dentro de la llamada generación de 1970 suele destacarse la visión del intimismo de los poetas novísimos y los afines a ellos, que tratan de evitar lo máximo posible en el poema las referencias a su intimidad y a las circunstancias de su realidad cotidiana. Para ello, hacen uso del repertorio de motivos culturales que se conoce como culturalismo, en una poesía concebida como independiente de la propia vida. Sin embargo, otros autores, coetáneos de los primeros, prefieren dejar que sus circunstancias vitales determinen la evolución de su obra artística. Para estos autores (entre los que puede citarse a Antonio Carvajal, Miguel d’Ors y Eloy Sánchez Rosillo), la poesía se construye con elementos de la propia vida y de la realidad circundante, aunque el resultado final sea una ficción. Y, de forma paradójica, el proceso de ficcionalización les permite descubrir lo que de esencial o universal hay en esas experiencias.
Genetic Mark–Recapture Improves Estimates of Maternity Colony Size for Indiana Bats
Authors: Oyler-McCance Sara J. , Fike Jennifer A. , Lukacs Paul M. , Sparks Dale W. , O'Shea Thomas J. , Whitaker John O.
Published: November 2017

Genetic mark–recapture methods are increasingly being used to estimate demographic parameters in species where traditional techniques are problematic or imprecise. The federally endangered Indiana bat Myotis sodalis has declined dramatically and threats such as white-nose syndrome continue to afflict this species. To date, important demographic information for Indiana bats has been difficult to estimate precisely using traditional techniques such as emergence counts. Successful management and protection of Indiana bats requires better methods to estimate population sizes and survival rates throughout the year, particularly during summer when these bats reproduce and are widely dispersed away from their winter hibernacula. In addition, the familial makeup of maternity colonies is unknown, yet important for understanding local and regional population dynamics. We had four objectives in this study. For the first two objectives we investigated the potential use of DNA from fecal samples (fecal DNA) collected at roosts to obtain genetically based mark–recapture estimates of 1) colony size and 2) survival rates, for an Indiana bat maternity colony in Indianapolis, Indiana. The third objective was to compare our genetically based colony-size estimates with emergence counts conducted at the same roost tree to evaluate the genetic mark–recapture method. Our fourth objective was to use fecal DNA to estimate levels of relatedness among individuals sampled at the roost. In the summer of 2008, we collected fecal pellets and conducted emergence counts at a prominent roost tree during three time periods each lasting 7 or 8 d. We genotyped fecal DNA using five highly polymorphic microsatellite loci to identify individuals and used a robust-design mark–recapture approach to estimate survival rates as well as colony size at the roost tree. Emergence count estimates at the roost tree ranged from 100 to 215, whereas genetic mark–recapture estimates were higher, ranging from 122 to 266 and more precise. Apparent survival was 0.994 (SE = 0.04) between sampling periods suggesting that few bats died or permanently emigrated during the course of the study. Relatedness estimates, r, between all pairs of individuals averaged 0.055 ranging from 0 to 0.779, indicating that most individuals were not closely related. We demonstrate here the promise of using fecal DNA to estimate demographic information for Indiana bats and potentially other bat species.
Reduction of Thermal Stress - Part I: Passivation Thickness Optimization of Standard Surface Bump Design
Authors: Sethu Raj Sekar , Kulkarni Salil Hari , Ha How Ung , Soon Kok Heng
Published: November 2017

Thermal cooling of solder bumps using Under Bump Metalization (UBM) with isotropic undercuts can result in an increase in stress concentration. The stress concentration on the passivation layers can result in cracking, especially when there are surface defects. Opportunities in reducing thermal stress depend on the type of passivation layer design as well as other factors. In Part I of this series of papers, the focus is on optimizing the thickness of the standard passivation design. In the standard passivation layer design, dielectrics would conformally cover the top metalization through two series of Chemical Vapor Deposition (CVD) coatings. Change in thickness for the two passivation layers' thickness using Finite Element Analysis (FEA) techniques combined with statistical Design of Experiments (DOE) allowed optimization of these layer thicknesses which brought about minimal stress on the passivation.
Durability and Reliability of Electro-Mechanical Relays for Oil and Gas
Authors: Rafie Saeed , Boulaknadal Youssef
Published: November 2017

Electro-mechanical relays (EMRs) are widely used in variety of manufacturing industries including oil and gas. One of their applications in the oil and gas industry is in the design of downhole logging wireline and measurement-while-drilling/logging-while-drilling (MWD/LWD) instruments such as magnetic resonance instruments, formation testing instruments, cement bond tools, etc.

EMRs are mainly electrically operated switches that multiplex high-powered circuits using a low-power signal. Typically, EMRs consist of one or two wire coils wrapped around magnetic cores, a movable armature, and a set of contact(s) that reside inside a sealed vacuum compartment.

The structural durability and reliability of EMRs has been the subject of research for many years, and these characteristics are considered a prime reliability concerns in the oil and gas industry. Their poor reliability has been documented by their several inherent failure modes, e.g., limited life expectancy due to shock, vibration, temperature and moisture, thermal stresses caused by soldering, contact wear, contact bouncing, and contact arcing/welding.

This paper presents results from a reliability study and an engineering assessment to determine the applicability and functionality of EMRs in electromagnetic-acoustic sensors. The discussion includes steps to improve and minimize the risk.
E-Band 4-Bit Phase Shifter using SP4T Flip Chip Switches
Authors: Chieh Jia-Chi Samuel , Nguyen Anh-Vu , Rowland Jason , Sharma Satish
Published: November 2017

A 4-bit millimeter-wave switched delay line phase shifter is presented. The phase shifter is designed using commercially available SP4T flip-chip millimeter-wave monolithic integrated circuits (MMICs) attached to an alumina substrate. The module operates in the E-Band from 82 – 84 GHz and has an average insertion loss of 20 dB. The size of the module is 10 mm × 7.5 mm. This paper presents a cost effective 4-bit E-Band phase shifter.
Surviving the Heat Wave – A presentation on thermally induced failures and reliability risks created by advancements in electronics technologies
Authors: Caswell Greg
Published: November 2017

Since the advent of surface mount technology back in the 1970's we, as an industry, have continually worked to miniaturize our products. This evolution of product design has impacted us at the semiconductor, package, circuit board and system levels. So, the question is, Why do Electronics Fail Under Thermal Cycling?

At the semiconductor level, you can have issues with delamination, IC complexity, degradation mechanisms, associated ceramic capacitor wearout, and electrical overstress (EOS). At the package level issues with bond wires and stacked die add to the reliability impact. At the printed circuit board level issues with solder wearout, solder phase coarsening, PWB laminates and glass materials, plated through hole (PTH) fatigue, and the impact of potting can also affect reliability while at the system level, heat sinks and other methods of heat removal can improve the situation.

What drives these issues is that we use a variety of materials e.g. semiconductors, ceramics, metals and polymers. We then bond them together with other materials like solder and adhesives. Each of these materials has a Coefficient of Thermal Expansion (CTE) that is unique and therefore expands and contracts at different rates.
Ultra-fine Cu Wiring Surrounded by Electroless-Plated Ni: Effective Structure for High Insulation Reliable Wiring Applicable to Panel Level Fabrication
Authors: Toba Masaya , Mitsukura Kazuyuki , Ejiri Yoshinori , Minegishi Tomonori , Kurafuchi Kazuhiko
Published: November 2017

Panel level packages such as 2.1D organic interposer and fan-out packages have been attracting the attention as a low cost substrate technology with high density fine wiring layers which interconnect multiple die set side by side. The Cu trench wirings for these packages are usually fabricated by fine and almost rectangular shaped pattern formation of insulation film followed by Ti/Cu sputtering as a seed layer formation, Cu electroplating and CMP. However, sputtering tends to be difficult to deposit on the side wall of almost rectangular shaped pattern. Another challenge is insulation reliability between ultra-fine wirings because electrochemical migration of Cu ion is one of the most serious problems for ultra-fine wirings. Here, instead of seed sputtering, we applied a Ni electroless plating because electroless plating is appropriate to panel process and Ni has high corrosion resistance. Ni seed was uniformly formed on both side wall and bottom of these rectangular patterns. After Cu electroplating, CMP and Ni selective electroless plating on Cu, Cu trench wiring fully surrounded by Ni in 1.5/1.5 μm of line and space was fabricated which has passed biased HAST over 200 h by suppressing corrosion of wiring.
Additive Packaging for Microwave Applications
Authors: Trulli Susan , Armiento Craig , Laighton Christopher , Harper Elicia , Haghzadeh Mahdi , Akyurtlu Alkim
Published: November 2017

This paper describes efforts to apply Additive Manufacturing (AM) technologies to microelectronic packaging of devices and subsystems for RF and microwave applications. This work, which was conducted at the Raytheon-University of Massachusetts Lowell Research Institute (RURI), is directed at a variety of applications such as 2D and 3D phased array antennas and tunable frequency selective surfaces (FSS). This paper will describe research on device modeling/simulation, formulation of novel functional inks, development of process/printing technologies and new material characterization techniques. Important elements of the additive packaging efforts include the integration of active die with printed components, replacement of wire bonds with printed chip interconnects and the development of integrated, printed connectors. Research on printed, tunable microwave components, such as varactors and phase shifters, are also discussed.
Integration and Miniaturization of a Ka-band Stepped Frequency Radar for Un-manned Aerial Vehicle Applications
Authors: McDaniel Jay W. , Yeary Mark B. , Sigmarsson Hjalti H. , Wolf J. Ambrose , Garrison Sean , Byers Kyle , Clewell Matthew
Published: November 2017

In this paper, we present a highly integrated and miniaturized Ka-band stepped frequency radar that can be used for un-manned aerial vehicle applications. The microwave portion of the radar is integrated onto a low temperature co-fired ceramic multi-chip module, utilizing a triple-print gold thick-film metallization, allowing for wire-bonding and solder capabilities. In addition to miniaturization, a metal seal frame was designed to surround the individual microwave circuits providing isolation barriers to reduce electromagnetic coupling within the system and disturbances from outside interferers. The radar implementation is based on a previous Ka-band radar system designed at the University of Oklahoma using connectorized commercial-off-the-shelf components. This new design results in a 64 times size reduction in foot-print area, half the power consumption, and greater than a 10 times weight reduction compared to the previous implementation. To ensure desired system performance is maintained, both radars were subjected to a direct loop-back test and the intermediate frequency output spectrums, prior to base-band down-conversion, are recorded and compared. Both outputs contain a spectrally pure tone at 12.8 GHz near the expected power indicating that the new radar performs as intended and is comparable to its predecessor. The packaging techniques presented show extreme promise for system integration and miniaturization of future radar and communication systems following the trend to reduce size, weight, and power.
Development of Stacking Process for 3D TSV (Through Silicon Via) Structure using Laser
Authors: Choi Kwang-Seong , Braganca Wagno Alves , Jang Keon-Soo , Bae Hyun-Cheol , Eom Yong-Sung
Published: November 2017

TSV chips were designed and fabricated to investigate the effects of the types of the stacking process on the manufacturability. Two processes were compared: thermocompression and laser bonding. The pitch of UBMs, solder bumps, and TSVs were 50μm. A fluxing underfill was developed and used as a pre-applied underfill during the stacking process. The bonding profiles and the solder joint morphology based on the thermocompression and the laser bonding were compared.
The IC in the Flexible Hybrid Electronics Technology: Flexibility and Bend Testing
Authors: Marinov Val R.
Published: November 2017

Flexible Hybrid Electronics (FHE) can be described as thinned, flexible silicon chips packaged on flexible circuit board (FCB) with printed conductors and passives. The flexibility of ICs can be achieved only if the thickness of the silicon is reduced to 50μm or less. The bend testing of the ultra-thin dies is a critical issue in the FHE technology as it allows to establish the fundamental relationships between the die flexural strength, die geometry, and the methods for thinning and dicing the silicon. The conventional bend tests are not adequate for testing ultra-thin dies. Presented is a semi-empirical test method, which allows for the estimation of the flexural strength of the highly compliant ultra-thin dies. The limiting Radius of Curvature (RoC) is an important parameter for the FHE device since it accounts for the bending characteristics of the entire FHE device, not only the IC. Presented is a simple analytical approach that allows to estimate the minimum RoC for an FHE assembly.
Fine Line Routing and Micro via Patterning in ABF Enabled by Excimer Laser Ablation
Authors: Hichri Habib , Fujishima Shohei , Lee Seongkuk , Arendt Markus , Nakamura Shigeo
Published: November 2017

Fan-Out technologies continue to be the main driver for advanced packaging, be it on wafer level (FOWLP) or panel level (FOPLP). There is a continuing need for higher density routing and heterogeneous integration of different devices, but also for continuous cost reduction. While traditional organic flip-chip substrates using semi-additive processes (SAP) have not been able to scale to ultra-fine RDL pitches and via opening below 10um, photo-sensitive spin-on dielectrics and RDL processes used for wafer level packaging do not sufficiently address the cost reduction need, and also face serious technical challenges. This paper presents the latest results from an innovative package RDL and micro via processes using excimer laser ablation in an especially developed non-photo sensitive material, to meet the market's most stringent requirements.

To enable panel and wafer based interposers to reduce RDL cost and scale interconnect pitch to 40um and below, excimer laser ablation is introduced as a direct patterning process that uses proven industrialized excimer laser sources to emit high-energy pulses at short wavelengths to remove polymer materials with high precision and high throughput. The combination of a high-power excimer laser source, large-field laser mask and precision projection optics enables the accurate replication and placement of fine resolution circuit patterns without the need for any wet-processing. With excimer laser patterning technology the industry gains a much wider choice of dielectric materials (photo and non-photo) to help achieve further reductions in manufacturing costs as well as enhancements in interposer and package performance.

In this paper, we propose a novel patterning process that uses excimer laser ablation to integrate via and RDL traces in one patterning step, followed by seed layer deposition, plating and planarization. The capability of this excimer laser patterning process in non-photo materials Ajinomoto Build-up Film, which is abbreviated to “ABF” in this paper, will be discussed, and its technical robustness and commercial advantages are demonstrated. We will present electrical and reliability data of Via and RDL traces patterned by excimer laser in ABF material.
Characterization of Ultra-Thin Epoxy-Resin Based Dielectric Substrate for Flexible Power Electronics Applications
Authors: Zhao Xin , Jagannadham K. , Reainthippayasakul Wuttichai , Lanagan Michael T. , Hopkins Douglas C.
Published: November 2017

Available substrate materials for power module applications has been investigated for a long time. Though Direct Bonded Copper (DBC) substrates, nowadays, have been widely applied in power electronics applications, especially power modules, due to its superior performance in mechanical ruggedness, thermal conductivity, and isolation capability. Its cost and complicated requirements during fabrication processes are always concerns in industries. At the same time, flexible electronics has become a rapidly expanding area with commercial applications including displays, medical, automotive, sensors arrays, wearable electronics, etc. This paper will initiate an investigation on a dielectric material that has potential in high power wearable electronics applications. A recently developed ultra-thin Epoxy-Resin Based Dielectric (ERBD) substrate material which is suitable for power electronic applications, is introduced. The ERBD can be fabricated with thickness as low as 80μm, with more than 5kV DC isolation capability. Its thermal conductivity is 8W/mK, higher than similar product currently available in the market. ERBD is also able to be bonded with Cu plates on both sides. In this paper, the properties of ERBD are investigated. Scanning Electron Microscope (SEM) is applied to analyze the microstructure of ERBD, and its bonding interface with Cu plates. 3-omega and Transient Thermal Reflectance methods are employed to precisely measure the thermal conductivity. Dielectric constant and loss are measured at different frequency. Simulations are applied to correct the error from the fringing effect during the measurement. The leakage current of ERBD is also measured under different voltage and temperature with DC and AC condition. Reliability tests are conducted to examine the electrical isolation and shearing strength of ERBD. The suitability of ERBD for potential flexible power electronics application is discussed based on the results from investigation of properties of the dielectric.
A Frequency Swept Low-Cost Capacitive Fringing Field PCB Sensor
Authors: Dean Robert N.
Published: November 2017

Reliable, low-cost sensors are important for many applications, including agriculture, pollution monitoring and weather forecasting. Commercial printed circuit board technology is being used to develop simple sensors for these applications, where the resistance or capacitance of the sensor is measured at a single frequency to determine useful information about an environmental parameter of interest. However, by measuring the complex impedance of the sensor over a wide frequency range, additional useful information can be obtained about the sensing environment. As a proof of principle, a suitable sensor was developed and evaluated in various aqueous solutions of interest using this technique. The measured sensor impedance was reduced to a capacitance versus frequency plot and a resistance versus frequency plot. Different aqueous solution chemistries resulted in characteristic signatures on these plots that could be useful in identifying the chemical compositions of the various solutions. Di-ionized water was used as a reference for chemical comparison. Various aqueous solution chemistries were then compared with DI water, resulting in corresponding signature differences of 10% to 50%.
Practical Application and Analysis of Lead-Free Solder on Chip-On-Flip-Chip SiP for Hearing Aids
Authors: Lee Youngtak , Link Doug
Published: November 2017

Due to rapid growth of the microelectronics industry, packaged devices with small form factors, low costs, high power performance, and increased efficiency have become of high demand in the market. To realize the current market development trend, flip chip interconnection and System-in-Package (SiP) are some of the promising packaging solutions developed. However, a surprising amount of surface mount technology (SMT) defects are associated with the use of lead-free solder paste and methods by which the paste is applied. Two such defects are solder extrusion and tombstoning. Considerable amount of defects associated with solder overflow are found on chip-on-flip-chip (COFC) SiP in hearing aids. Through the use of design of experiments (DOE), lead-free solder defect causes on hearing aids application can be better understood and subsequently reduced or eliminated. This paper will examine the failure modes of solder extrusion and tombstoning that occurred when two different types of lead-free solders, Sn-Ag-Cu (SAC) and BiAgX were used within a SiP for attachment of surface mount devices (SMD) chip components for hearing aid applications. The practical application and analysis of lead-free solder for hearing aids will include the comprehensive failure analysis of the SMD components and compare the modeling and analysis of the two different solder types through the DOE process.
Innovative Integration Solutions for SiP Packages Using Fan-Out Wafer Level eWLB Technology
Authors: Lim Jacinta Aman , Pandey Vinayak
Published: November 2017

Fan-Out Wafer Level Packaging (FOWLP) has been established as one of the most versatile packaging technologies in the recent past and already accounts for a market value of over 1 billion USD due to its unique advantages. The technology combines high performance, increased functionality with a high potential for heterogeneous integration and reduced overall form factor as well as cost effectiveness. The increasing complexities in achieving a higher degree of performance, bandwidth and better power efficiency in various markets are pushing the boundaries of emerging packaging technologies to smaller form factor packaging designs with finer line/width spacing as well as improved thermal/electrical performance and the integration of System-in-Package (SiP) or 3D capabilities.

SiP technology has been evolving through utilization of various package technology building blocks to serve the market needs with respect to miniaturization, higher integration, and smaller form factor as cited above, with the added benefits of lower cost and faster time to market as compared to silicon (Si) level integration, which is commonly called system-on-chip or SoC. As such, SiP incorporates flip chip (FC), wire bond (WB), and fan-out wafer-level packaging (FOWLP) as its technology building blocks and serves various end applications ranging from radio frequency (RF), power amplifiers (PA), Micro-Electro-Mechanical-Systems (MEMS) and Sensors, and connectivity, to more advanced application processors (AP), and other logic devices such as graphics processing units (GPUs)/central processing units (CPUs). FOWLP, also referred to as advanced embedded Wafer Level Ball Grid Array (eWLB) technology, provides a versatile platform for the semiconductor industry's technology evolution from single or multi-die 2D package designs to 2.5D interposers and 3D SiP configurations.

This paper presents developments in SiP applications with eWLB/Fan-out WLP technology, integration of various functional blocks such as wire bonding, Package-on-Package (PoP), 2.5D, 3D, smaller form factor, embedded passives, multiple redistribution layer routing and z-height reduction. Test vehicles have been designed and fabricated to demonstrate and characterize these low profile and integrated packaging solutions for mobile products including Internet of Things (IoT)/wearable electronics (WE), MEMS and sensors. Finer line/width spacing of 2/2mm with multiple redistribution layers (RDL) are fabricated and implemented on the eWLB platform to enable higher interconnect density and signal routing. Assembly process details, component level reliability, board level reliability and characterization results for eWLB SiP will be discussed.
Using SPICE to Model Nonlinearities Resulting from Heterogeneous Integration of Complex Systems
Authors: Beal Aubrey N. , Dean Robert N.
Published: November 2017

Complex systems have been modeled using SPICE. This modeling allows extension of the linear models of Si MEMS into the nonlinear regime. Previously, such analysis involved many different simulation tools. These SPICE simulation methods allow for modeling nonlinear devices alongside their supporting electronics in one simulator. Nonlinear spring constants have been modeled using SPICE and it is shown that bifurcation occurs due to large amplitude excitation. This results in nonlinear and even chaotic oscillations similar to those found in the Duffing oscillator.