bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinching - An Innovative Trend in Joining of Combined Materials in Car Body Production
Authors: Kaščák Luboš , Spišák Emil , Spišáková Emília , Gajdoš Ivan
Published: May 2015

Various ferrous and non-ferrous materials and their combinations are used in car body production in automotive industry. The most commonly used method for joining the materials is resistance spot welding. Some materials or combinations of materials are very difficult or impossible to join by resistance spot welding. Therefore, car producers are seeking for alternative joining methods. One of the innovative joining alternatives is clinching. The paper presents the results of evaluation of clinched joint properties. The high-strength dual-phase steel sheet DP600 in combination with the drawing grade steel sheets DC06, DX53D+Z and DX51D+Z were used for experiments. The influence of position of the sheets relative to the punch and die of the tool on the carrying capacities of the clinched joints was observed as well. The tension test and metallographical analysis were used for the evaluation of clinched joint properties.
Analysis of Laser Welds on Automotive Steel Sheets
Authors: Viňáš Ján , Ábel Milan
Published: May 2015

The paper presents results of quality analysis of the welded joints realized by CO2 laser (AF8P) using automotive body sheets and sheets for car chassis. There were used double-sided galvanized steel sheets of different grades and thicknesses. Welded joints were evaluated visually and then carrying capacity of the joints was established using tensile test. Welded joints were tested by following destructive tests: microhardness, macro and microstructure of the joints on metallographic sections using light microscopy. Results showed that the welding parameters were chosen appropriately.
The Influence of Punch-Die Clearance on Blanked Edge Quality in Fine Blanking of Automotive Sheets
Authors: Spišák Emil , Majerníková Janka , Spišáková Emília
Published: May 2015

Fine blanking is a widely used process that permits the production of precise finished components which are cleanly sheared through the whole cutting surface. It can be eliminated secondary operations, such as milling, grinding, etc. Many studies on the weight reduction of automobile for fuel saving were underway. The clearance of the punch-die of a fine blanking tool is an important design factor that affects the sheared surface of a product. If the clearance is too big, a fractured surface would occur in the product while if it is too small, bulging would occur. The main objective of this paper is to provide an overview of the effect of clearance between punch and die in a fine blanking tool on quality of sheared surface. A well as to specify the effect of mechanical properties of sheared steel sheet on blanked edge quality given by ratio of hv/a0.
The Evaluation of Surface Quality for Particular Parts of Forging Die
Authors: Ižol Peter , Beňo Jozef
Published: May 2015

Forming dies are often costly for producers and the cost amount is influenced by production process too. If the die is manufactured by machining, proper strategies would necessary to consider as well. The right selection of adequate strategy helps production times shortening, tool wear reducing and those affect production effectiveness. Used strategies and its parameters are often compromise between acceptable surface quality and variations in shape aside, and production time on the other side. The paper presents the way of evaluation of milling strategy based on selected elements of forming die. This allows choosing the adequate strategy for particular shapes of die and also to evaluate them by the reached surface quality. Presented approach is verified by machining forging die cavity for production of connecting rod.
The New Knowledge of Environmentally Friendly Joints Made by Thermal Drilling
Authors: Sobotová Lýdia , Badida Miroslav
Published: May 2015

The contribution deals with possibilities of new progressive technologies in materials joining processes. By using of friction, physical factors as temperature and thermal conductivity in joining, we can increase the quality of material joining and can join of various types of material. There is also shortage the production time, provide automation in operations is possible, spare of economical expenses and also we can protect the environment. The product increasing of automobile industry, pipe industry, development of mechanical products, materials, design of joining in civil engineering force the producers to accelerate the production and to utilize new technologies.
X-Ray Microtomograph Detection of Internal Defects for a UD Prepreg Composite
Authors: Petrů Michal , Syrovátková Martina , Kolínová Marcela , Novák Ondra
Published: May 2015

The current trend particularly in industrial and commercial sectors is to search for alternatives to the current structural materials made from new lightweight materials. One option is to use unconventional material composite structures which have a combined fibre/matrix. Analysis of UD prepregs with unidirectional carbon fibres was performed. These special unconventional materials can be used for both flat and shaped structural products. The extent and quality of the saturation of the fibre layers in the resulting composite are important features for the whole complex of its parameters and influence its quality and mechanical properties. The experimental study also included an exploration of the inner structure and interactions of the individual components and detection of internal defects in the carbon UD prepreg composite using an X-ray microtomograph. The results illustrated the detection of microcracks, which significantly influence the resulting synergy of the composite and which were previously undetected.
Formation of the Surface Layers of a Material with Shape-Memory-Based TiNiCo Diffusion Metallization
Authors: Rusinov Peter Olegovich , Blednova Zhesfina Michailovna
Published: May 2015

The formation of a surface layer of diffused TiNiCo was carried out by metallization of fusible metal melt under isothermal conditions in an argon atmosphere at a temperature of 1100–1150 °C. The driving force of the process is the difference in concentration of alloying elements on the surface of the workpiece melt. A melt of lead or eutectic Pb-Bi was used as a transport medium, whose elements are in saturated atomic state and in direct contact with the surface of workpieces. This molten surface-activated product was purified from oxide films, providing a high wettability, which in turn provides good adhesion. Dissolved melt powders of Ti, Ni, and Co were first adsorbed on the surface of the items and then diffused into the surface of the volume. The cementation process was carried out cyclically by lifting the melt products every 25–30 minutes. The duration of the saturation process was 11–13 hours, depending on the desired coating thickness.
Influence of Electrodeposited Coatings on Ultra-High-Cycle Fatigue Life of S235 Structural Steel
Authors: Nový František , Trško Libor , Ulewicz Robert , Dundeková Sylvia
Published: May 2015

The article deals with experimental results of fatigue life of plain carbon steel electrodeposited with nickel, chromium and iron-zinc coatings in the ultra-high-cycle region of loading (N = 6×106÷ 1010cycles) obtained at high-frequency fatigue testing (f ≈ 20 kHz, T = 20 ± 5 °C, R = -1). The results confirm continuous decrease of S-N curves after N = 107cycles. Electrodeposited coatings caused decrease of the fatigue life in the low and high-cycle fatigue region. In the ultra-high cycle region the influence of electrodeposited coatings on fatigue properties is negligible. There was observed no significant influence of thickness of electrodeposited coatings on fatigue lifetime decrease.
Evaluation of AlTiCrN Coatings Surface after Tribological Tests
Authors: Brezinová Janette , Jakubéczyová Dagmar , Landová Mariana
Published: May 2015

The article deals with the issue of evaluation of thin coatings for coating of cutting tools in order to increase their lifetime at higher temperatures. The aim of the experimental work was to determine the quality of two types of coatings - AlTiNmulti and AlTiCrN. The coatings were applied to the material Böhler 190 Microclean using PLATIT PL1001 Compact device at temperature of 430°C and pressure of 0,020 mbar. To determine the quality of coatings tribological test Pin-on-Disc was used, the counterpart was made of tungsten carbide (WC). Outputs of measurements were evaluated in Sensomp, which evaluates the results obtained from measurements using microscope PLu Noex. The results of the tests show that the AlTiNmulti coating is most suitable for use in environments with higher temperatures.
Morphology Characteristics of Coatings for Forming Applications
Authors: Draganovská Dagmar , Evin Emil , Tomáš Miroslav
Published: May 2015

The contribution focuses to study of selected properties of thin coatings deposited on tool steel. Used samples were prepared by PVD method. Samples were evaluated using the scanning electron microscopy. Characteristics of surface morphology Ra, Rz Rt, RSm and RPc were established according to standard STN EN ISO 4287. The coatings TiN, TiCN, Supral and Exxtral Plus have been deposited on tool steel substrate having a thickness of 16 mm. The morphology characteristics were compared to the surface morphology of the reference material tool steel X155CrVMo12.1.
The Biology and Disease Relevance of CD300a, an Inhibitory Receptor for Phosphatidylserine and Phosphatidylethanolamine
Authors: Zenarruzabeitia Olatz , Vitallé Joana , Eguizabal Cristina , Simhadri Venkateswara R. , Borrego Francisco
Published: May 2015

The CD300a inhibitory receptor belongs to the CD300 family of cell surface molecules that regulate a diverse array of immune cell processes. The inhibitory signal of CD300a depends on the phosphorylation of tyrosine residues embedded in ITIMs of the cytoplasmic tail. CD300a is broadly expressed on myeloid and lymphoid cells, and its expression is differentially regulated depending on the cell type. The finding that CD300a recognizes phosphatidylserine and phosphatidylethanolamine, two aminophospholipids exposed on the outer leaflet of dead and activated cells, has shed new light on its role in the modulation of immune functions and in its participation in the host response to several diseases states, such as infectious diseases, cancer, allergy, and chronic inflammatory diseases. This review summarizes the literature on CD300a expression, regulation, signaling pathways, and ligand interaction, as well as its role in fine tuning immune cell functions and its clinical relevance.
Proximal Rectus Femoris Avulsion: Ultrasonic Diagnosis and Nonoperative Management
Authors: Esser Stephan , Jantz David , Hurdle Mark F. , Taylor Walter
Published: May 2015

Objective

To present a case of ultrasonic diagnosis and nonoperative management of a complete proximal rectus femoris avulsion in a National Collegiate Athletic Association Division 1 soccer goalkeeper.

Background

While delivering a goal kick, a previously uninjured 24-year-old collegiate soccer goalkeeper had the sudden onset of right anterior thigh pain. He underwent rehabilitation with rapid resolution of his presenting pain but frequent intermittent recurrence of anterior thigh pain. After he was provided a definitive diagnosis with musculoskeletal ultrasound, he underwent an extended period of rehabilitation and eventually experienced complete recovery without recurrence.

Differential Diagnosis

Rectus femoris avulsion, rectus femoris strain or partial tear, inguinal hernia, or acetabular labral tear.

Treatment

Operative and nonoperative options were discussed. In view of the player's recovery, nonoperative options were pursued with a good result.

Uniqueness

Complete proximal rectus femoris avulsions are rare. Our case contributes to the debate on whether elite-level kicking and running athletes can return to full on-field performance without surgery.

Conclusions

Complete proximal rectus femoris avulsions can be treated effectively using nonoperative measures with good preservation of function even in the elite-level athlete. In addition, musculoskeletal ultrasound is an excellent tool for on-site evaluation and may help guide prognosis and management.
Advances in SPECT for Optimizing the Liver Tumors Radioembolization Using Yttrium-90 Microspheres
Authors: Roshan Hoda , Azarm Ahmadreza , Mahmoudian Babak , Islamian Jalil
Published: May 2015

Radioembolization (RE) with Yttrium-90 ( 90 Y) microspheres is an effective treatment for unresectable liver tumors. The activity of the microspheres to be administered should be calculated based on the type of microspheres. Technetium-99m macroaggregated albumin ( 99m Tc-MAA) single photon emission computed tomography/computed tomography (SPECT/CT) is a reliable assessment before RE to ensure the safe delivery of microspheres into the target. 90 Y bremsstrahlung SPECT imaging as a posttherapeutic assessment approach enables the reliable determination of absorbed dose, which is indispensable for the verification of treatment efficacy. This article intends to provide a review of the methods of optimizing 90 Y bremsstrahlung SPECT imaging to improve the treatment efficacy of liver tumor RE using 90 Y microspheres.
Hybrid Single-Photon Emission Computed Tomography/Computed Tomography Imaging Features of Tumoral Calcinosis in Technetium-99m Methylene Diphosphonate Bone Scintigraphy
Authors: Kamaleshwaran Koramadai , Asokumar Premkumar , Malaikkal Anjali , Mohanan Vyshakh , Shinto Ajit
Published: May 2015

Tumoral calcinosis (TC) is an uncommon ectopic calcification syndrome. TC is a benign condition characterized by the presence of large calcific soft tissue deposits occurring predominantly in a periarticular location. It generally occurs as a complication of renal dialysis or trauma, and is rarely seen in familial and sporadic cases. Bone scintigraphy is a sensitive method for diagnosing TC. We report a case of year old female with. She underwent bone scintigraphy to see the sites of involvement, which showed intense foci of tracer activity in soft tissue in bilateral thigh and gluteal region. Hybrid single-photon emission computed tomography/computed tomography of the pelvis and thigh localized tracer uptake to the calcification in the gluteal and thigh region.
Algebraische Zahlentheorie
Authors: Howard Benjamin V. , Kings Guido , Sujatha Ramdorai , Venjakob Otmar
Published: May 2015

The workshop brought together leading experts in Algebraic Number Theory. The talks presented new methods and results that intertwine a multitude of topics ranging from classical diophantine themes to modern arithmetic geometry, modular forms and p-adic aspects in number theory.
Calculus of Variations
Authors: Brendle Simon , De Lellis Camillo , Jerrard Robert L.
Published: May 2015

The Calculus of Variations is at the same time a classical subject, with long-standing open questions which have generated deep discoveries in recent decades, and a modern subject in which new types of questions arise, driven by mathematical developments and by emergent applications. This workshop balanced the traditional variational problems with novel questions with origins in diverse areas, such as economic models of the academic labor market, or differential geometry in metric emasure spaces. In particular, the meeting featured presentations on regularity theory, existence, and classification questions related to minimal surfaces, surfaces of prescribed Gaussian curvature, and mean curvature flow; domain optimization problems; nonlinear elasticity; calibrated geometries; variational formulations of certain dynamical problems; and stochastic variational problems.
Cryptography
Authors: Buchmann Johannes A. , Goldwasser Shafi
Published: May 2015

The Oberwolfach workshop
Cryptography
brought together scientists from cryptography with mathematicians specializing in the algorithmic problems underlying cryptographic security. The goal of the workshop was to stimulate interaction and collaboration that enables a holistic approach to designing cryptography from the mathematical foundations to practical applications. The workshop covered basic computational problems such as factoring and computing discrete logarithms and short vectors. It addressed fundamental research results leading to innovative cryptography for protecting security and privacy in cloud applications. It also covered some practical applications.
Reactive Flows in Deformable, Complex Media
Authors: Gerritsen Margot , Nordbotten Jan Martin , Pop Iuliu Sorin , Wohlmuth Barbara
Published: May 2015

Many processes of highest actuality in the real life are described through systems of equations posed in complex domains. Of particular interest is the situation when the domain is variable, undergoing deformations that depend on the unknown quantities of the model. Such kind of problems are encountered as mathematical models in the subsurface, or biological systems. Such models include various processes at different scales, and the key issue is to integrate the domain deformation in the multi-scale context. Having this as the background theme, this workshop focused on novel techniques and ideas in the analysis, the numerical discretization and the upscaling of such problems, as well as on applications of major societal relevance today.
Informação e trabalho na sociedade capitalista contemporânea
Authors: Silva Edilene Maria da , Tabosa Hamilton Rodrigues , Santos Williams , Alves Edvaldo Carvalho
Published: May 2015

O artigo discute questões relativas às mudanças ocorridas no mundo do trabalho informacional (relações homem – instrumentos/equipamentos, homem-sociedade) a partir de considerações sobre o avanço tecnológico da atualidade e suas relações com o capitalismo. Apresenta reflexões sobre a evolução das teorias administrativas e a produção de software e ilustra como a reificação do trabalho informacional foi conduzida de acordo com os ditames das tecnologias de informação e comunicação e dos modelos gerenciais.
Productos y servicios informacionales como evidencia de la aplicación de procesos de gestión de la información y del conocimiento en centros de información
Authors: Limonta Favier Zunilka , Otero Caballero Evelyn Milagro , Álvarez Cambas Elizabeth , Ripoll Moreno Yaima
Published: May 2015

Se analiza la gestión de la información y del conocimiento como factores determinantes en el logro de los objetivos organizacionales del Centro de Información y Gestión Tecnológica (CIGET) de Guantánamo, Cuba. Para el caso se abordaron ambos procesos como enfoques unificados e interdependientes. Los efectos de la aplicación de estos enfoques se traducen y se evidencian en cuatro productos y servicios informacionales generados por el CIGET.
Políticas públicas de inclusión digital: El caso de América Latina y Cuba
Authors: Bisset Alvarez Edgar , Grossi de Carvalho Angela Maria , Gregorio Vidotti Silvana Aparecida Borsetti
Published: May 2015

Objetivo. Abordar el desarrollo de políticas públicas vinculadas a la inclusión digital en países de América Latina y en especial Cuba y análisar el comportamiento de este fenómeno en el área y las acciones realizadas por los diferentes gobiernos permitiendo mostrar cómo se ha comportado el desarrollo de políticas y proyectos de inclusión digital en América Latina y Cuba. Método. Para profundizar en este análisis, se realizó una revisión bibliográfica que permitió ubicarnos en un contexto teórico-conceptual de este fenómeno. Se consultaron bases de datos internacionales que facilitaron el acceso a información que permitió arribar a varias conclusiones. Conclusiones. A pesar de los esfuerzos realizados para disminuir la brecha digital, esta crece en la medida que se desarrollan nuevas tecnologías afectando a la población de menos recursos, se percibe también una tendencia en el crecimiento del uso de las TIC´s en Cuba y América Latina.
Studies on Genetic Diversity of Selected Population of Hybrid Scallop Chlamys farreri（♀）× Patinopecten yessoensis（♂） by Microsatellites Markers
Authors: Wu Biao , Yang Aiguo , Cheng Ningning , Sun Xiujun , Liu Zhihong , Zhou Liqing
Published: May 2015

The growth superiority of hybrid scallop Chlamys farreri (♀) × Patinopecten yessoensis (♂), as the following successive generation selection have been reported. However, the data about the genetic diversity in those population remains unexplored. In this study, the genetic structure analysis of F1, F2 and F3 were conducted by PCR with 10 Simple Sequence Repeats (SSR) primers. It showed that a total of 68 alleles were detected, and the number of alleles per locus ranged from 3 to 11, Polymorphism Information Content (PIC) per locus ranged from 0.4729 to 0.8429. And, the average observed heterozygosity (Ho) of the three populations were 0.6100, 0.6975 and 0.7750, while the average expected heterozygosity (He) were 0.7607, 0.7751 and 0.7379 respectively. Fst values among the three populations were also low (Fst<0.05) which suggested low genetic differentiation between each two populations. In all, those data indicated the genetic structure challenge caused by hybridization and selection, supplying a new angle to understand artificial selective breeding.
PARLOMA – A Novel Human-Robot Interaction System for Deaf-Blind Remote Communication
Authors: Russo Ludovico Orlando , Farulla Giuseppe Airò , Pianu Daniele , Salgarella Alice Rita , Controzzi Marco , Cipriani Christian , Oddo Calogero Maria , Geraci Carlo , Rosa Stefano , Indaco Marco
Published: May 2015

Deaf-blindness forces people to live in isolation. At present, there is no existing technological solution enabling two (or many) deaf-blind people to communicate remotely among themselves in tactile Sign Language (t-SL). When resorting to t-SL, deaf-blind people can communicate only with people physically present in the same place, because they are required to reciprocally explore their hands to exchange messages. We present a preliminary version of PARLOMA, a novel system to enable remote communication between deaf-blind persons. It is composed of a low-cost depth sensor as the only input device, paired with a robotic hand as the output device. Essentially, any user can perform hand-shapes in front of the depth sensor. The system is able to recognize a set of hand-shapes that are sent over the web and reproduced by an anthropomorphic robotic hand. PARLOMA can work as a “telephone” for deaf-blind people. Hence, it will dramatically improve the quality of life of deaf-blind persons. PARLOMA has been presented and supported by the main Italian deaf-blind association, Lega del Filo d'Oro. End users are involved in the design phase.
TP-Space RRT – Kinematic Path Planning of Non-Holonomic Any-Shape Vehicles
Authors: Blanco Jose Luis , Bellone Mauro , Gimenez-Fernandez Antonio
Published: May 2015

The autonomous navigation of vehicles typically combines two kinds of methods: a path is first planned, and then the robot is driven by a local obstacle-avoidance controller. The present work, which focuses on path planning, proposes an extension to the well-known rapidly-exploring random tree (RRT) algorithm to allow its integration with a trajectory parameter-space (TP-space) as an efficient method to detect collision-free, kinematically-feasible paths for arbitrarily-shaped vehicles. In contrast to original RRT, this proposal generates navigation trees, with poses as nodes, whose edges are all kinematically-feasible paths, suitable to being accurately followed by vehicles driven by pure reactive algorithms. Initial experiments demonstrate the suitability of the method with an Ackermann-steering vehicle model whose severe kinematic constraints cannot be obviated. An important result that sets this work apart from previous research is the finding that employing several families of potential trajectories to expand the tree, which can be done efficiently under the TP-space formalism, improves the optimality of the planned trajectories. A reference C++ implementation has been released as open-source.
Epigenetic Mechanisms of Human Papillomavirus–Associated Head and Neck Cancer
Authors: Anayannis Nicole V. J. , Schlecht Nicolas F. , Belbin Thomas J.
Published: May 2015

Context

Growing evidence suggests that as many as half of all oropharyngeal squamous cell carcinomas (OPSCCs) harbor human papillomavirus (HPV) infections. Despite being more advanced at diagnosis, HPV-positive OPSCCs are associated with a better response to therapy and longer patient survival than HPV-negative OPSCCs. Human papillomavirus–positive OPSCC has also been shown to have distinct host gene expression profiles compared with HPV-negative OPSCC. Recently, this distinction has been shown to include the epigenome. It is well supported that cancers are epigenetically deregulated. This review highlights epigenetic differences between HPV-positive and HPV-negative OPSCCs. The epigenetic mechanisms highlighted include methylation changes to host and viral DNA, and host chromatin modification. We also review the current evidence regarding host DNA methylation changes associated with smoking, and deregulation of microRNA expression in HPV-positive OPSCC.

Objective

To provide an overview of epigenetic mechanisms reported in HPV-positive OPSCC, with analogies to cervical cancer, and discussion of the challenges involved in studying epigenetic changes in HPV-associated OPSCC in combination with changes associated with smoking.

Data Sources

Sources were a literature review of peer-reviewed articles in PubMed on HPV and either OPSCC or head and neck squamous cell carcinoma, and related epigenetic mechanisms.

Conclusions

Epigenetic changes are reported to be a contributing factor to maintaining a malignant phenotype in HPV-positive OPSCC. The epigenetic mechanisms highlighted in this review can be studied for potential as biomarkers or as drug targets. Furthermore, continued research on the deregulation of epigenetic mechanisms in HPV-positive OPSCC (compared with HPV-negative OPSCC) may contribute to our understanding of the clinical and biologic differences between HPV-positive and HPV-negative OPSCC.
Adaptation, Integration, and Connection: How Water Utilities Can Plan for Uncertainty
Authors: Atwater Richard , Atwater Patrick , Atwater ew , Cruz Johnathan
Published: May 2015

Developing adaptive capacity through better use of data can help prepare utilities for extreme weather, climate change, and whatever the future holds.
The Role of Water Efficiency in Future Water Supply
Authors: Dyballa Cindy , Hoffman H.W. (Bill)
Published: May 2015

Progress made in water efficiency over the past 25 years has laid the groundwork for more integrated water efficiency programs and requirements that will emerge in the next 25 years. Looking to connections with energy use and environmental issues illustrates the value of these integration efforts for a smart and sustainable water utility of the future.
社会网络与商业信用: 基于 “结构洞” 位置的证据
Authors: Chen Yunsen
Published: May 2015

A firm’s social network can provide it with competitive advantage, while its trade credit may reflect the competitiveness of its business operations. Unfortunately, there is a lack of crossover studies looking at both social networks and business credit. This paper investigates the influence of a firm holding different structural hole positions on its trade credit. By defining networks as directors’ interlocking positions and using social network analysis to compute the structural holes, this study demonstrates empirically that firms with more structural holes get more trade credit, thereby enhancing their competitive advantage in the market, and their trade credit-cash sensitivity also decreases. These results hold after controlling for the endogeneity problem and the influence of a network centrality measure. Additional analyses show that the influence of structural hole position on trade credit is more obvious in highly competitive industries and regions that have a higher level of marketisation. Moreover, the effect is found mainly for larger and more mature firms and those situated in a worse information environment, and often manifests during a time of loose monetary policies. The results suggest that the control and information advantages obtained by positioning in structural holes are important in enabling firms to obtain trade credit, which can enhance their competitive advantage. The conclusions contribute to the literature on social network and corporate finance.
Joint inversion for global isotropic and radially anisotropic mantle structure including crustal thickness perturbations
Authors: Chang Sung‐Joon , Ferreira Ana M. G. , Ritsema Jeroen , van Heijst Hendrik J. , Woodhouse John H.
Published: May 2015

We present a new global whole‐mantle model of isotropic and radially anisotropic S velocity structure (SGLOBE‐rani) based on ~43,000,000 surface wave and ~420,000 body wave travel time measurements, which is expanded in spherical harmonic basis functions up to degree 35. We incorporate crustal thickness perturbations as model parameters in the inversions to properly consider crustal effects and suppress the leakage of crustal structure into mantle structure. This is possible since we utilize short‐period group‐velocity data with a period range down to 16 s, which are strongly sensitive to the crust. The isotropic S velocity model shares common features with previous global S velocity models and shows excellent consistency with several high‐resolution upper mantle models. Our anisotropic model also agrees well with previous regional studies. Anomalous features in our anisotropic model are faster SV velocity anomalies along subduction zones at transition zone depths and faster SH velocity beneath slabs in the lower mantle. The derived crustal thickness perturbations also bring potentially important information about the crustal thickness beneath oceanic crusts, which has been difficult to constrain due to poor access compared with continental crusts.
A process‐based investigation into the impact of the Congo basin deforestation on surface climate
Authors: Bell Jean P. , Tompkins Adrian M. , Bouka‐Biona Clobite , Sanda I. Seidou
Published: May 2015

The sensitivity of climate to the loss of the Congo basin rainforest through changes in land cover properties is examined using a regional climate model. The complete removal of the Congo basin rainforest results in a dipole rainfall anomaly pattern, characterized by a decrease (∼−42%) in rainfall over the western Congo and an increase (∼10%) in the basin's eastern part. Three further experiments systematically examine the individual response to the changes in albedo, surface roughness, and evapotranspiration efficiency that accompany deforestation. The increased albedo (∼) caused by the Congo basin rainforest clearance results in cooler and drier climate conditions over the entire basin. The drying is accompanied with a reduction in available surface energy. Reducing evapotranspiration efficiency or roughness length produces similar positive air temperature anomaly patterns. The decreased evapotranspiration efficiency leads to a dipole response in rainfall, similar to that resulting from a reduced surface roughness following Congo basin rainforest clearance. This precipitation anomaly pattern is strongly linked to the change in low‐level water vapor transport, the influence of the Rift valley highlands, and the spatial pattern of water recycling activity. The climate responds linearly to the separate albedo, surface roughness, and evapotranspiration efficiency changes, which can be summed to produce a close approximation to the impact of the full deforestation experiment. It is suggested that the widely contrasting climate responses to deforestation in the literature could be partly due to the relative magnitude of change of the radiative and nonradiative parameterizations in their respective land surface schemes.
The role of foehn in the formation of heavy air pollution events in Urumqi, China
Authors: Li X. , Xia X. , Wang L. , Cai R. , Zhao L. , Feng Z. , Ren Q. , Zhao K.
Published: May 2015

The impact of sandwich foehn on air pollution in Urumqi, a gap town located on the northern lee side of the Tianshan Mountains of China, is analyzed. The results show that during days with high pollution, the boundary layer over the city and the down‐valley area can be divided into a three‐layer structure, with the southeasterly foehn sandwiched between the northwesterly winds on top and the cold air surface pool beneath. The southeasterly foehn at heights between 480 and 2100 m results in a very stable boundary layer structure. In combination with the decoupling between the foehn flow and cold air pool, such boundary layer structure prevents vertical mixing of atmospheric pollutants. In the up‐valley area from the northern lee side flank to the southern urban area, the ground‐based foehn confronts the thermally driven valley breeze and forms a “minifront,” which moves northward in the morning and retreats southward in the afternoon. Although the minifront disappears in the early evening, the wind shear of the mountain breeze between the southern suburb and downtown areas is still remarkable, which is favorable for a convergence line to persist around the city all day long. In this case, air pollutants emitted from the up‐valley and down‐valley areas are transported toward the urban area. Therefore, the air pollutants accumulate daily, leading to the frequent occurrence of heavy pollution events in Urumqi. This indicates that the sandwich foehn plays a critical role in the formation of heavy air pollution events in Urumqi.
Horizontal winds derived from the polar mesospheric cloud images as observed by the CIPS instrument on the AIM satellite
Authors: Rong P. P. , Yue J. , Russell J. M. , Lumpe J. D. , Gong J. , Wu D. L. , Randall C. E.
Published: May 2015

A cloud pattern matching technique is applied to polar mesospheric cloud (PMC) images taken by the Cloud Imaging and Particle Size instrument (CIPS) to infer the wind velocities in the mesopause region. CIPS measurements are analyzed to detect patterns that repeat from one orbit to the next but are displaced in location; the displacement provides a measure of the wind velocity. Pattern matching is achieved by resampling the CIPS data to longitude and latitude grids with the grid‐box size forced at ~5 km in both directions. The correlated patterns are searched within a geographic region referred to as a “frame” of ~500 km in longitude × 400 km in latitude. The histograms of the derived velocities indicate that easterly winds prevail, with a mean zonal wind of −20 to −15 m/s. Mean meridional winds are overall small, but in late summer the histogram indicated a poleward wind of ~20–30 m/s. The variability of CIPS cloud albedo on consecutive orbits is also examined at fixed geolocations. The statistical results suggest that ~86% of pairs underwent mean cloud albedo variation of < 50% on consecutive orbits, suggesting a moderate change. It is also found that the correlation of the cloud structures between two consecutive orbits at a fixed location is generally poor. These findings suggest that cloud patterns are subject to wind advection, but the cloud patches are more extended in size than the movement that occurs. Cloud voids are found to be more likely to remain at the same geolocations.
Assimilation of thermodynamic information from advanced infrared sounders under partially cloudy skies for regional NWP
Authors: Wang Pei , Li Jun , Goldberg Mitchell D. , Schmit Timothy J. , Lim Agnes H. N. , Li Zhenglong , Han Hyojin , Li Jinlong , Ackerman Steve A.
Published: May 2015

Generally, only clear‐infrared spectral radiances (not affected by clouds) are assimilated in weather analysis systems. This is due to difficulties in modeling cloudy radiances as well as in observing their vertical structure from space. To take full advantage of the thermodynamic information in advanced infrared (IR) sounder observations requires assimilating radiances from cloud‐contaminated regions. An optimal imager/sounder cloud‐clearing technique has been developed by the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin‐Madison. This technique can be used to retrieve clear column radiances through combining collocated multiband imager IR clear radiances and the sounder cloudy radiances; no background information is needed in this method. The imager/sounder cloud‐clearing technique is similar to that of the microwave/IR cloud clearing in the derivation of the clear‐sky equivalent radiances. However, it retains the original IR sounder resolution, which is critical for regional numerical weather prediction applications. In this study, we have investigated the assimilation of cloud‐cleared IR sounder radiances using Atmospheric Infrared Sounder (AIRS)/Moderate Resolution Imaging Spectroradiometer for three hurricanes, Sandy (2012), Irene (2011), and Ike (2008). Results show that assimilating additional cloud‐cleared AIRS radiances reduces the 48 and 72 h temperature forecast root‐mean‐square error by 0.1–0.3 K between 300 and 850 hPa. Substantial improvement in reducing track forecasts errors in the range of 10 km to 50 km was achieved.
Dual‐frequency radar Doppler spectral retrieval of rain drop size distributions and entangled dynamics variables
Authors: Tridon F. , Battaglia A.
Published: May 2015

A novel technique based on Ka‐W band dual‐wavelength Doppler spectra has been developed for the simultaneous retrieval of binned rain drop size distributions (DSD) and air state parameters like vertical wind and air broadening caused by turbulence and wind shear. The rationale underpinning the method consists in exploiting the peculiar features observed in Doppler spectra caused by the wavelength dependence of scattering and absorption properties. A notional study based on a large data set of DSDs measured by a two‐dimensional video disdrometer demonstrates that the retrieval performs best for small/moderate air broadening spectral width and when mean volume diameters exceed at least 1 mm. The retrieval is also limited to ranges below cloud base and where the signal‐to‐noise ratio of both radars exceed 10 dB, which rules out regions affected by strong attenuation. Broadly speaking, it is applicable to rain rates comprised between roughly 1 and 30 mm h−1. Preliminary retrieval for observations at the Atmospheric Radiation Measurement Southern Great Plains site shows very good agreement with independent reflectivity measurements from a 0.915 GHz wind profiler. The proposed methodology shows great potential in linking microphysics to dynamics in rainfall studies.
Long‐term variations in the dissolved oxygen budget of an urbanized tidal river: The upper Delaware Estuary
Authors: Tomaso Daniel J. , Najjar Raymond G.
Published: May 2015

The dissolved oxygen budget in the upper Delaware Estuary between 1970 and 2014 was inferred from oxygen concentration measurements using a box model approach. The region was found to be a net biogeochemical sink of oxygen, with net oxygen consumption greater in the tidal fresh portion than in the oligohaline portion. Net oxygen consumption decreased from the 1970s to the 1990s by roughly a factor of 2 before increasing slightly in the 2000s. The dramatic decline in oxygen consumption was presumably due to improvements in wastewater treatment, though a comparison with biological oxygen demand measurements in wastewater was equivocal. Nonalgal oxygen consumption (i.e., oxygen consumption due to heterotrophic respiration and nitrification) was computed as the sum of the estimated net oxygen consumption and historical measurements of primary production. Nonalgal oxygen consumption was found to be highly seasonal and positively correlated with temperature, with Q10 values ranging between 1.4 and 2.3. Annual nonalgal oxygen consumption was found to be several times annual primary production. Exchange with the atmosphere is the main process that balances the net oxygen consumption throughout the study region, with advection also an important process in the tidal fresh portion. Decadal scale variability in oxygen concentration, including the recent decline in the 2000s, appears to be mainly driven by biological, not physical, processes.
A new method for direction finding based on Markov random field model
Authors: Ota Mamoru , Kasahara Yoshiya , Goto Yoshitaka
Published: May 2015

Investigating the characteristics of plasma waves observed by scientific satellites in the Earth's plasmasphere/magnetosphere is effective for understanding the mechanisms for generating waves and the plasma environment that influences wave generation and propagation. In particular, finding the propagation directions of waves is important for understanding mechanisms of VLF/ELF waves. To find these directions, the wave distribution function (WDF) method has been proposed. This method is based on the idea that observed signals consist of a number of elementary plane waves that define wave energy density distribution. However, the resulting equations constitute an ill‐posed problem in which a solution is not determined uniquely; hence, an adequate model must be assumed for a solution. Although many models have been proposed, we have to select the most optimum model for the given situation because each model has its own advantages and disadvantages. In the present study, we propose a new method for direction finding of the plasma waves measured by plasma wave receivers. Our method is based on the assumption that the WDF can be represented by a Markov random field model with inference of model parameters performed using a variational Bayesian learning algorithm. Using computer‐generated spectral matrices, we evaluated the performance of the model and compared the results with those obtained from two conventional methods.
Contrasting styles of (U)HP rock exhumation along the Cenozoic Adria‐Europe plate boundary (Western Alps, Calabria, Corsica)
Authors: Malusà Marco G. , Faccenna Claudio , Baldwin Suzanne L. , Fitzgerald Paul G. , Rossetti Federico , Balestrieri Maria Laura , Danišík Martin , Ellero Alessandro , Ottria Giuseppe , Piromallo Claudia
Published: May 2015

Since the first discovery of ultrahigh pressure (UHP) rocks 30 years ago in the Western Alps, the mechanisms for exhumation of (U)HP terranes worldwide are still debated. In the western Mediterranean, the presently accepted model of synconvergent exhumation (e.g., the channel‐flow model) is in conflict with parts of the geologic record. We synthesize regional geologic data and present alternative exhumation mechanisms that consider the role of divergence within subduction zones. These mechanisms, i.e., (i) the motion of the upper plate away from the trench and (ii) the rollback of the lower plate, are discussed in detail with particular reference to the Cenozoic Adria‐Europe plate boundary, and along three different transects (Western Alps, Calabria‐Sardinia, and Corsica‐Northern Apennines). In the Western Alps, (U)HP rocks were exhumed from the greatest depth at the rear of the accretionary wedge during motion of the upper plate away from the trench. Exhumation was extremely fast, and associated with very low geothermal gradients. In Calabria, HP rocks were exhumed from shallower depths and at lower rates during rollback of the Adriatic plate, with repeated exhumation pulses progressively younging toward the foreland. Both mechanisms were active to create boundary divergence along the Corsica‐Northern Apennines transect, where European southeastward subduction was progressively replaced along strike by Adriatic northwestward subduction. The tectonic scenario depicted for the Western Alps trench during Eocene exhumation of (U)HP rocks correlates well with present‐day eastern Papua New Guinea, which is presented as a modern analog of the Paleogene Adria‐Europe plate boundary.
Evolution of brown carbon in wildfire plumes
Authors: Forrister Haviland , Liu Jiumeng , Scheuer Eric , Dibb Jack , Ziemba Luke , Thornhill Kenneth L. , Anderson Bruce , Diskin Glenn , Perring Anne E. , Schwarz Joshua P. , Campuzano‐Jost Pedro , Day Douglas A. , Palm Brett B. , Jimenez Jose L. , Nenes Athanasios , Weber Rodney J.
Published: May 2015

Particulate brown carbon (BrC) in the atmosphere absorbs light at subvisible wavelengths and has poorly constrained but potentially large climate forcing impacts. BrC from biomass burning has virtually unknown lifecycle and atmospheric stability. Here, BrC emitted from intense wildfires was measured in plumes transported over 2 days from two main fires, during the 2013 NASA SEAC4RS mission. Concurrent measurements of organic aerosol (OA) and black carbon (BC) mass concentration, BC coating thickness, absorption Ångström exponent, and OA oxidation state reveal that the initial BrC emitted from the fires was largely unstable. Using back trajectories to estimate the transport time indicates that BrC aerosol light absorption decayed in the plumes with a half‐life of 9 to 15 h, measured over day and night. Although most BrC was lost within a day, possibly through chemical loss and/or evaporation, the remaining persistent fraction likely determines the background BrC levels most relevant for climate forcing.
Direct observations of the full Dungey convection cycle in the polar ionosphere for southward interplanetary magnetic field conditions
Authors: Zhang Q.‐H. , Lockwood M. , Foster J. C. , Zhang S.‐R. , Zhang B.‐C. , McCrea I. W. , Moen J. , Lester M. , Ruohoniemi J. M.
Published: May 2015

Tracking the formation and full evolution of polar cap ionization patches in the polar ionosphere, we directly observe the full Dungey convection cycle for southward interplanetary magnetic field (IMF) conditions. This enables us to study how the Dungey cycle influences the patches' evolution. The patches were initially segmented from the dayside storm enhanced density plume at the equatorward edge of the cusp, by the expansion and contraction of the polar cap boundary due to pulsed dayside magnetopause reconnection, as indicated by in situ Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations. Convection led to the patches entering the polar cap and being transported antisunward, while being continuously monitored by the globally distributed arrays of GPS receivers and Super Dual Auroral Radar Network radars. Changes in convection over time resulted in the patches following a range of trajectories, each of which differed somewhat from the classical twin‐cell convection streamlines. Pulsed nightside reconnection, occurring as part of the magnetospheric substorm cycle, modulated the exit of the patches from the polar cap, as confirmed by coordinated observations of the magnetometer at Tromsø and European Incoherent Scatter Tromsø UHF radar. After exiting the polar cap, the patches broke up into a number of plasma blobs and returned sunward in the auroral return flow of the dawn and/or dusk convection cell. The full circulation time was about 3 h.