bluuebunny/crossref_metadata_2025 huggingface dataset:
Automated fabrication of hybrid thermoplastic prepreg material to be processed by In-Situ Consolidation Automated Fiber Placement process
Authors: Iannone Vincenzo , Barile Marco , Lecce Leonardo
Published: August 2018

This work deals with the fabrication of an innovative hybrid thermoplastic prepreg by continuous hot forming process. The material, suitable also for Automated Fiber Placement process, is produced through a consolidation of commercial PEEK-Carbon Fiber prepreg sandwiched between two amorphous PEI films. Consolidation is performed by a purpose-designed automated prototype equipment operating on defined pressure and thermal cycles. Then preliminary tests on first trials produced were carried out. These activities have been developed in the frame of the NHYTE project, a Research and Innovation Action funded by the European Union's H2020 framework programme, under Grant Agreement No 723309 NOVOTECH acting as Coordinator presents this paper on behalf of all Partners of the project. The proof of NHYTE project concept is the manufacturing of a fastener free and high performing fuselage portion demonstrator.
Ballistic impact response of 2024-T3 monolithic aluminum plates: prediction and comparison with GLARE 4A fiber-metal laminates
Authors: Bikakis George , Tsigkros Nikolaos , Sideridis Emilios , Savaidis Alexander
Published: August 2018

This article deals with the evaluation of the ballistic resistance of aluminum plates subjected to high velocity impact by a rigid cylindrical projectile. Important impact variables such as the ballistic limit, the ballistic energy and the impact load time history are predicted using the ANSYS LS-DYNA software. A comparison with the ballistic resistance of GLARE 4A fiber-metal laminated plates is also implemented. The time history of the transient impact load of the collision on the aluminum targets is analyzed and useful conclusions are drawn. It is found that the ballistic limit and the ballistic energy of aluminum and GLARE 4A panels increase as their thickness and their areal weight become higher. It is also found that 2024-T3 aluminum plates offer comparable ballistic limit velocities with the GLARE 4A fiber-metal laminates of the same thickness or the same areal weight.
Characterization of fatigue failed aged Cu-Ni-Si alloys
Authors: Atapek Ş. Hakan , Pantelakis Spiros G. , Chamos Apostolos N. , Çelik Gülşah Aktaş
Published: August 2018

The precipitation hardenable and non-toxic Cu-Ni-Si alloys are good alternatives to Cu-Be and Cu-Co-Ni-Be alloys due to their high strength and high conductivity that can be attained by not only alloying but also thermo-mechanical routes. In this study, the fractographic analysis was carried out to understand the fatigue failure of aged 2.55Ni-0.55Si-0.25Zr-0.25Cr (wt-%) alloy which is a member of Corson family. In fatigue tests, a constant amplitude loading was applied at a stress ratio (R = σmin/σmax) of -1 and different stress levels (400, 350, 200 and 175 MPa) were used. The fracture response of the alloy was discussed depending on the applied stress levels and microstructural features. It was concluded that (i) Ni,Zr-rich precipitates and Cr-rich precipitates at the grain boundaries caused crack nucleation at all stress levels and (ii) the interaction between Ni-rich silicides and dislocations at lower stress level resulted in localized shearing and fine striations.
Fatigue Lives of Power Plant Structures Due to Load Sequence Effects Originating from Fluctuating Production of Renewable Energy
Authors: Vormwald Michael , Bosch Alexander , Schackert Sophie , Schweizer Christoph
Published: August 2018

The change in operation of power plants due to the increasing use of renewable energies causes additional stresses to the components by a high number of smaller load cycles. This fact results in a demand for validated new approaches to estimate fatigue life especially for welded joints that are the weak parts within the piping. The components are operated in the LCF regime where short fatigue crack growth determines the life. Therefore, a non-linear fracture mechanics based approach is appropriate. For the development and validation of the model, an experimental campaign was performed including fatigue tests of smooth specimens with various microstructures of X6CrNiNb18-10 (AISI 347) as well as specimens containing mechanical and microstructural notches. Experiments are performed with all types of specimens with an increasing complexity from constant to variable amplitude loading, the latter also applied as pseudo-random sequence derived from measurements in power plants. The developed non-linear fracture mechanics based model uses the effective cyclic J-Integral normalized to the crack length to replace crack growth calculation by a linear damage accumulation. To consider the loading history an algorithm for the calculation of crack opening and crack closure is used. The advantages of this approach are evident when comparing calculated with experimentally determined fatigue lives. Remaining differences serve for further considerations of how to improve the life prediction for variable amplitudes.
Mechanical and Fractographical Characterization of Extruded Al-Mg-Si-Zr Alloys
Authors: Kahrıman Fulya , Zeren Muzaffer
Published: August 2018

In this study, the chemical composition of Al-0.8Mg-0.8Si alloys was modified with the addition of 0.1 and 0.2 wt.-% Zr. The billets were manufactured by direct chill casting method, homogenized at 560 °C for 6h and then extruded in order to obtain profiles having hollow and circular sections. Recrystallization layer (shell) became narrower due to the addition of Zr. This was attributed to the formation of very fine precipitates (Al3Zr) within the matrix. The mechanical properties showed that both yield and tensile strengths increased as a function of Zr content. Tensile fracture surfaces were examined by scanning electron microscope and the fractographs reflected the effect of grain structure on the fracture behavior of studied alloys. All fracture surfaces indicated typical dimple ruptures, however, the size of dimples were observed as finer structures as a function of Zr content. As seen in cross-sectional graphs, as the Zr content increased the grain structure was refined due to Al3Zr precipitates. These fine precipitates caused the formation of fine and shallow dimples under loading.
Microstructure and surface degradation of Al reinforced by AlxW intermetallic compounds via different fabrication routes
Authors: Lekatou Angeliki G. , Mpalanou Maria , Lentzaris Konstantinos , Karantzalis Alexander E. , Melanitis Nikolaos
Published: August 2018

In the present effort, Al-AlxW composites have been prepared by vacuum arc melting (VAM), conventional casting (CAST) and free sintering (PM) with the objective to determine an effective fabrication route in terms of low cost, ease of manufacture and property boosting. The produced Aluminium Matrix Composites (AMCs) contain several types of in-situ aluminides. Their morphology, stoichiometry and distribution strongly depend on the fabrication route. The particulate aluminide reinforcements have a beneficial effect on the wear response of the monolithic matrix. VAM-AMCs show the highest resistance to wear. A wear mechanism is proposed.
Solid particle erosion response of aluminum reinforced with tungsten carbide nanoparticles and aluminide particles
Authors: Chantziara Ekaterini , Lentzaris Konstantinos , Lekatou Angeliki G. , Karantzalis Alexander E.
Published: August 2018

The main concept behind this work is to further enhance the attractive properties of aluminum by fabricating Al - WC composites and evaluating them in terms of their solid particle erosion response. Aluminum Matrix Composites (AMCs) were produced by the addition of submicron sized WC particles (up to 2.5vol %) into a melt of Al1050. Casting was assisted by the use of K2TiF6 as a wetting agent and mechanical stirring in order to minimize particle clustering. Extensive presence of in-situ intermetallic phases (Al4W, Al5W, Al12W, Al3(Ti,W), Al3Ti) was observed in the cast products. Particle distribution was reasonably uniform comprising both clusters and isolated particles. Solid particle erosion experiments were carried out for impact angles of 30°, 60° and 90°, using angular Al2O3 particles as the eroding medium and under 5 bar spraying pressure. The erosion rate was calculated by measuring the mass loss and the eroded surfaces were examined with SEM-EDX. Increased erosion resistance was observed for low particle additions (≤ 1.0 vol%WC). Finally, a possible erosion mechanism was proposed based on the material’s microstructural and morphological characteristics.
Contiguous notches interaction on Ck45 shaft under reversed bending loading: experimental, metallographical and analytical approach
Authors: Tsolakis Antonios D. , Giannakopoulos Konstantinos I. , Makarigakis Efstathios D.
Published: August 2018

In mechanical engineering design it is common for multiple stress concentration areas to coexist adjacently, where the existing analytical theory cannot be used to assess the effect. The effect of adjacent step and keyway on a DIN CK 45 shaft has been investigated in the present paper. For this purpose, a DIN CK45 steel shaft specimen with a standardized keyway and a diameter-step has been tested under rotating bending in order to investigate the interaction of two distinct stress concentration areas. All fragment specimens have metallographically examined. Analytical and numerical methods have been used to support the conclusions.
Additive manufacture of superduplex stainless steel using WAAM
Authors: Eriksson Magnus , Lervåg Malin , Sørensen Camilla , Robertstad Andreas , Brønstad Bård M. , Nyhus Bård , Aune Ragnhild , Ren Xiaobo , Akselsen Odd M.
Published: August 2018

Superduplex stainless steels have been used in the oil and gas industry for a couple of decades due to the combination of excellent mechanical properties and corrosion resistance. The present investigation addresses the applicability of wire and arc additive manufacturing for this steel grade. Due to the inherent rapid heating and cooling, the initial base metal microstructure will be substantially altered, and complex thermal cycles may cause the formation of brittle secondary phases, among which the frequently observed intermetallic sigma phase is most harmful. However, no intermetallic phases have been observed, which is consistent with the low heat input employed, and the high Ni content in the wire. The microstructure observations in terms of ferrite volume fraction, Cr nitrides precipitation and the formation of secondary austenite are discussed together with the hardness measurements, tensile testing and notch toughness testing. It is concluded that additive manufacturing of superduplex stainless steels by wire and arc process is feasible.
Hot Cracking Mechanisms in Welding Metallurgy: A Review of Theoretical Approaches
Authors: Manitsas Dimosthenis , Andersson Joel
Published: August 2018

Hot cracking often refers to the appearance of liquid films along grain boundaries or to another place in the weld metal structure. Despite hot cracking importance in alloy weldability, there is limited understanding of the influencing mechanisms. Theories and criteria worked out over the years to assess alloy weldability will be presented. The review focuses on: 1) Theories of hot cracking, 2) Hot cracking criteria, and 3) A criticism of hot cracking theories and criteria.
Investigation of In-service Creep Failures of Aircraft Ti-6Al-4V Bolts
Authors: Spyroglou Iordanis , Kourousis Kyriakos , Koutsomichalis Angelos
Published: August 2018

Three Ti-6Al-4V bolts from mid-life jet aircraft failed during service operation. Each of the failed bolts were installed on a landing gear component. Metallurgical failure analysis indicated that the fracture mechanism is low temperature creep, possibly resulting from a sustained tension load over a long time. Visual inspection revealed ductile fracture morphology with no macroscopic deformation or corrosion. For all bolts fracture occurred close to the root at the first pitches of the thread. Scanning Electron Microscope (SEM) analysis revealed dimple morphologies with micro-void coalescence. Energy Dispersive X-Ray (EDX) analysis did not reveal any material deficiency that would have precipitated failure.
Mitigation of Turbine Vane Shock Waves Through Trailing Edge Cooling
Authors: Cakir Bora O. , Saracoglu Bayindir H.
Published: August 2018

The immense market demand on the high efficiency and lightweight aero-engines results in designs with compact high-pressure turbine stages experiencing supersonic flow field. In supersonic turbines, shocks appear at the vane trailing edges. The interaction of these shock with the neighbouring airfoils and blades on the adjacent rotor row and consequently create considerable amount of losses on the aerodynamic performance of the turbine. Moreover, periodic excitation created by the interaction of the shock waves and the motion of the turbine rotor causes fatigue problems and reduces the lifetime of the engine. Current study aims to alter the vane shock waves through blowing at the trailing edge. In order to characterize the effect of active blowing on the trailing edge flow field, a series of URANS simulations were conducted on OpenFOAM solver platform. Various blowing schemes were simulated over a simplified trailing edge geometry exposed in supersonic flow. The computations were compared in terms of shock intensity, oscillation frequency and exerted pressure forcing over the downstream components. The results showed that unsteady trailing edge blowing were able to modify the fluctuations observed on the shocks by altering the shock intensity, angle and frequency of oscillations. The classification of the wake unsteadiness, i.e. vortex shedding, in terms of trailing edge characteristics were also accomplished through frequency domain analysis of simulations.
Tackling Failure through Discovery of Semantic Neighbors Nodes in WSNs
Authors: Dima Sofia Maria , Antonopoulos Christos , Koubias Stavros
Published: August 2018

Wireless Sensor Networks (WSNs) are attracting active and increasing research interest in various application fields including industrial control and environmental applications. In such cases accurate event detection is of utmost importance, thus sensors' data need to be fused through a sophisticated process (i.e. data mining algorithms). In this context, semantic correlations between sensor nodes and formation of semantic clusters is critical as it enables the fusion of specific sensor data regardless of the proximity criteria. Traditional clustering schemes aim to extend sensors' network lifetime using criteria such as received signal strength, while the semantic correlation is frequently omitted. In this paper, two novel techniques for discovering semantic neighbors are proposed, Diffusion Algorithm for Discover Semantic Neighbors (DADSN) and Trace Route Algorithm for Discover Semantic Neighbors (TRA-DSN). Design and development efforts are analysed while the evaluation results offer a useful guideline on which technique fits better in different WSNs deployments.
Responding to Failure Events in the Manufacturing Environment
Authors: Anagnostopoulos Christos , Alexakos Christos , Fournaris Apostolos , Koulamas Christos , Kalogeras Athanasios
Published: August 2018

The manufacturing environment is characterized by increased complexity with different devices, systems and applications that need to interoperate, while residing at different layers of the classical industrial environment hierarchy. The introduction of the Industrial Internet of Things with increasingly smarter devices drives towards flatter hierarchies. This paper deals with an architecture for integration of IIoT devices in the manufacturing environment utilizing a Multi Agent System to this end. This extended architecture is utilised so as to perform failure detection of both IIoT devices and manufacturing resources, and react by altering the manufacturing process either automatically or semi-automatically.
Fault tolerant area coverage control for multiagent systems
Authors: Papatheodorou Sotiris , Tzes Anthony
Published: August 2018

The fault tolerance characteristics of a distributed multi-agent coverage algorithm are examined. A team of sensor-equipped mobile agents is tasked with covering a planar region of interest. A distributed, gradient-based control scheme is utilized for this purpose. The agents are assumed to consist of three subsystems, each one of which may fail. The subsystems under examination are the actuation, sensing and the communication subsystem. Partial and catastrophic faults are examined. Several simulation studies are conducted highlighting the robustness of the distributed nature of the control scheme to these classes of faults, even when several of them happen at the same time.
Befragung von Ärzten zum Umgang mit dem Thema „Tabakkonsum bei Patienten mit Lungenkrebs“
Authors: Bleckwenn Markus , Kaluç Asya , Zipfel Mathias , Schnakenberg Rieke , Brossart Peter , Weckbecker Klaus
Published: August 2018

Einleitung Etwa 40 % der Patienten sind bei der Diagnosestellung Lungenkrebs aktive Raucher. Die Hälfte dieser Patienten setzt den Nikotinkonsum trotz bestehender Krebserkrankung fort. Die Gesamtsterblichkeit liegt bei diesen Patienten um den Faktor 3 höher. Zudem steigt die Lebensqualität und Symptome wie Husten und Luftnot werden reduziert.

Fragestellung Wie gehen die behandelnden Ärzte mit dem Tabakkonsum ihrer Patienten mit Lungenkrebs um?

Methoden Es wurden insgesamt 14 Ärzte des Universitätsklinikums Bonn aus den Abteilungen Pneumologie, Onkologie und Thoraxchirurgie befragt, die in die Behandlung des Lungenkrebses eingebunden sind. Die Interviews wurden transkribiert und nach der qualitativen Inhaltsanalyse nach Mayring mit MAXQDA®12 ausgewertet.

Ergebnisse Die Ärzte gingen sehr individuell mit dem Nikotinkonsum ihrer Patienten um. Dabei orientierten sich die Ärzte vorwiegend an der möglichen Lebenserwartung der Patienten. Bei einem kurativen Behandlungsansatz setzten die Ärzte einen Rauchstopp bei ihren Patienten für eine erfolgreiche Behandlung voraus. Im Rahmen einer palliativen Behandlung wollten viele Ärzte ihren Patienten die Belastung einer Raucherentwöhnung nicht mehr zumuten. Kam der Wunsch nach einer Entwöhnungstherapie beim Patienten auf, wurde in der Regel auf Kollegen verwiesen, die in Raucherentwöhnung geschult waren. Hindernisse für die selbstständige Durchführung einer Raucherentwöhnung waren insbesondere fehlende Kenntnisse und kurze Behandlungszeiten bzw. eine hohe Anzahl an Patienten, vor allem während der Sprechstunde.

Diskussion Die Ärzte waren durchaus vom Nutzen eines Rauchstopps bei der Behandlung des Lungenkarzinoms überzeugt. Patienten mit Lungenkrebs würden davon profitieren, wenn die Raucherentwöhnung noch mehr in die Gesamttherapie integriert wäre. Dazu könnte man auf bereits etablierte Entwöhnungsprogramme und Konzepte für Kliniken zurückgreifen.
Versorgung geriatrischer Patienten in Radeburg
Authors: Kuphal Andrea
Published: August 2018

Best Practise Menschen haben unterschiedliche gesundheitsbezogene Versorgungsbedarfe. Beim älteren Menschen spricht man von geriatrischem Bedarf. Dieser
kann akutgeriatrisch und/oder frührehabilitativ oder rehabilitativ sein. Wechsel zwischen den verschiedenen Bedarfen sind entsprechend des jeweiligen
Gesundheitszustands des Patienten bzw. Rehabilitanden möglich. Die Fachkliniken für Geriatrie in Radeburg bestehen aus dem Fachkrankenhaus für Geriatrie, kurz
Akutgeriatrie, und der Geriatrischen Rehabilitationsklinik. Somit sind unter einem Dach beide vollstationären Versorgungsmöglichkeiten nach §§ 39 i.V. mit 109
SGB V bzw. nach §§ 40 i.V. mit 111 SGB V gegeben.
Systemische Chemotherapie beim Urothelkarzinom in Deutschland – Eine Umfrage der Arbeitsgemeinschaften Urologische Onkologie und Internistische Onkologie der Deutschen Krebsgesellschaft e.V.
Authors: Hupe Marie , Merseburger Axel , de Wit Maike , Rexer Heidrun , Gschwend Jürgen , Krege Susanne
Published: August 2018

Hintergrund Im Jahr 2016 wurde die erste deutsche S3-Leitlinie zum Harnblasenkarzinom veröffentlicht. Im Rahmen dieser Studie soll die nationale Versorgungssituation des Urothelkarzinoms in Deutschland mit Fokus auf die medikamentöse Therapie aufgearbeitet, anhand aktueller Leitlinienempfehlungen bewertet sowie mit internationaler Literatur zu ähnlicher Fragestellung verglichen werden.

Material und Methoden Es wurde ein Fragebogen entwickelt und an über 4000 Urologen und Onkologen in Deutschland versandt. Der Fragebogen beinhaltete Fragen zum jährlichen Patientenaufkommen sowie zur Anwendung der operativen und hauptsächlich medikamentösen Therapieoptionen in den verschiedenen Stadien des Urothelkarzinoms. Es konnten 278 Fragebögen ausgewertet werden.

Ergebnisse Dieses ist die größte deutschlandweite Querschnittsstudie zur systemischen Therapie des Urothelkarzinoms. Im Bereich der palliativen Systemtherapie werden die Leitlinienempfehlungen ausgeschöpft. Bei den Indikationen für eine intravesikale Instillationstherapie sowie (neo)adjuvante Chemotherapie besteht Optimierungspotenzial hinsichtlich der Leitlinienadhärenz, v. a. im Hinblick auf die Anzahl verabreichter Chemotherapiezyklen.

Schlussfolgerung Insgesamt sollte die Leitlinienadhärenz verbessert werden. Neben neuen Diagnose- oder Therapieoptionen könnte auch eine striktere Leitlinienadhärenz die krebsspezifische Mortalität perspektivisch verringern.
Implementation of a Quality Control System for Laparoscopic Pyloromyotomy in Hypertrophic Pyloric Stenosis: Hurdles and Pitfalls
Authors: Ploeg Mirjam , Keyzer-Dekker Claudia M. G. , Sloots Cornelius E. J. , van de Ven Cornelis P. , Meeussen Conny , Wijnen Rene M. H. , Vlot John
Published: August 2018

Background In 2011, we implemented a new video-based system for quality control of laparoscopic pyloromyotomy. More than 3 years later, we evaluated how the implementation had gone and assessed its usability in predicting postoperative outcomes.

Materials and Methods Four key point images or short video-segments were to be recorded perioperatively: prepyloromyotomy, parallel-mobility testing, perforation testing, and postpyloromyotomy. Data of all 134 patients undergoing laparoscopic pyloromyotomy from September 2011 to December 2014 were analyzed retrospectively. Five pediatric surgeons independently assessed the anonymized operative images for predicting reoperation and time to full-enteral feeding.

Results The percentage of operations during which images were recorded increased from 45% in 2012 to 75% in 2014. Over the study period, one or more images were recorded in 89 of the 134 (66%) patients. In only 17 of 89 patients (19%), all four images were documented. The key point images or videos were made for prepyloromyotomy in 49%, parallel-mobility testing in 85%, perforation testing in 42%, and postpyloromyotomy in 94% of 89 patients. Five patients (3.7%) were reoperated for incomplete pyloromyotomy (N = 4) or mucosal perforation (N = 1). Images were recorded during the first operation in four of the five reoperated patients. The need of reoperation was correctly predicted for two of the four patients. Full-enteral feeding within 24 hours was correctly predicted for 67% of the patients (range: 47–88%).

Conclusion The increase in recorded images over the years is promising. The implementation of the quality control system did not contribute to a significant decrease in the complication rate, which was already very low. Still, reoperation or a protracted postoperative course could only be predicted with moderate accuracy from the operative images, therefore, for now the use of perioperative images in a medicolegal setting should be advised against. Improved compliance with image recording and better instructions for evaluating the images might improve the usefulness of perioperative images in, e.g., telementoring, education, and medicolegal practice.
Immobilization following Distal Radius Fractures: A Randomized Clinical Trial
Authors: Hill J. , Bouz Gabriel , Azad Ali , Pannell William , Alluri R. , Ghiassi Alidad , Navo Paul
Published: August 2018

Background No consensus exists regarding postoperative splinting position following volar plate fixation of distal radius fractures.

Purpose The purpose of this study was to determine whether immobilization in supination would result in superior outcomes compared with no restriction of forearm range of motion.

Patients and Methods All patients >18 years of age with distal radius fractures indicated for volar plate fixation were eligible. Exclusion criteria were open fracture and concomitant injury to, or functional deficit of, either upper extremity. Patients were randomized to immobilization in (1) maximal supination with a sugar-tong splint or (2) no restriction of supination with a volar splint. Patient-Rated Wrist Evaluation (PRWE), Disabilities of the Arm, Shoulder, and Hand (DASH) score, and visual analog scale (VAS) score; wrist range of motion; and grip strength were recorded at 2 and 6 weeks postoperatively. A Student's t-test was used to compare mean values of all outcome measures at each time point.

Results A total of 46 patients enrolled in the study; 28 were immobilized with a volar splint and 18 were immobilized with a sugar-tong splint. Six-week follow-up data were obtained for 32 patients. There was no significant difference in PRWE, DASH, and VAS scores; or range of motion; or grip strength between the two groups postoperatively.

Conclusion Range of motion, grip strength, and patient-rated outcome measures were similar regardless of postoperative immobilization technique in patients with a distal radius fractures stabilized with a volar plate. Surgeons can elect to use the standard-of-care postoperative immobilization modality of their preference following volar plate fixation without compromising short-term return to function.

Level of Evidence This is a Level II, therapeutic study.
Minimally Invasive Plate Osteosynthesis for Extra-articular Distal Radius Fracture in Postmenopausal Women: Longitudinal versus Transverse Incision
Authors: Galmiche Chloé , Rodríguez Gustavo , Xavier Fred , Igeta Yuka , Hidalgo Diaz Juan , Liverneaux Philippe
Published: August 2018

Background This work aimed to compare two mini-invasive palmar approaches (longitudinal and transverse) to osteosynthesize fractures of the distal radius. The main hypothesis was that the longitudinal technique gave smaller incisions. The secondary hypothesis was that the longitudinal technique would be better for the recovery of pain, functional scores, strength, and mobility.

Materials and Methods The series included 30 extra-articular distal radius fractures in 30 patients (average age: 74 years) fixed with volar locking plate using a mini-invasive technique. Fifteen of these patients had a single longitudinal surgical approach (Group I), and 15 had a transverse approach that was completed with a longitudinal incision for the proximal screws (Group II).

Results The combined average incision size was 14.73 mm in Group I and 19.8 mm in Group II. After 6 months, the pain was on average 1.4/10 (Group I) and 0.46/10 (Group II), the quick Disability of the Arm, Shoulder, and Hand was 13.63/100 (Group I) and 2.8/100 (Group II), Patient-Related Wrist Evaluation was 11.8/100 (Group I) and 5.97/100 (Group II), grip strength was 81.06% (Group I) and 72.13% (Group II), flexion was 88.13% (Group I) and 75% (Group II), extension was 86% (Group I) and 64.6% (Group II), ulnar inclination was 89% (Group I) and 78.67% (Group II), radial inclination was 89.73% (Group I) and 79.93% (Group II), pronation was 96.67% (Group I) and 81.46% (Group II), and supination was 91.93% (Group I) and 79.87% (Group II).

Clinical Relevance The longitudinal technique gave smaller incisions than the transverse technique. Among the secondary hypotheses, all the variables were better with the longitudinal technique, except the pain, although without any significant difference.
Arthroscopic Treatment of Translunate Perilunate Injuries, Not Dislocated (PLIND)
Authors: Herzberg Guillaume , Cievet-Bonfils Maxime , Burnier Marion
Published: August 2018

Background Translunate perilunate dislocations were recently described as well as perilunate injuries, not dislocated (PLIND). The authors present a case of transradial styloid, translunate PLIND which sustained a full arthroscopic reduction and internal fixation.

Case Description A 33-year-old man sustained a transradial styloid, translunate PLIND due to a fall from a truck with his wrist in hyperextension. The diagnosis was made at the acute stage. Full arthroscopic reduction and internal fixation with Kirschner wires was performed, followed by a 6 weeks' immobilization period. Uneventful healing of both the lunate and radial styloid were observed at 6 weeks and confirmed with a computed tomography scan. At 4 years of follow-up, the Lyon wrist score was 78% (good).

Literature Review Very few lunate fractures are described in the literature. Translunate perilunate dislocations were recently described as well as PLIND. To the best of the authors' knowledge, a case of transradial styloid, translunate PLIND which sustained a full arthroscopic reduction and internal fixation has never been reported so far.

Clinical Relevance This case reports a unique pattern of transradial styloid, translunate PLIND and outlines the usefulness of a full arthroscopic treatment. An open reduction for this pattern of injury would have been extensive, difficult, and probably unreliable.
Survival Rate on a 10-Year Follow-Up of Total Wrist Replacement Implants: A 23-Patient Case Series
Authors: Honecker Sophie , Igeta Yuka , Al Hefzi Ali , Pizza Chiara , Facca Sybille , Liverneaux Philippe
Published: August 2018

Background According to current literature, the estimated average survival rate for Remotion, the total wrist implants, is above 90% on an 8-year follow-up. We examined our series of Remotion to calculate its survival rate on a 10-year follow-up.

Case Description A total of 23 cases of total wrist implants were reviewed. The case series included 22 patients, 18 females and 4 males, of an average age of 55 years. The case series included 19 inflammatory rheumatic diseases, 3 Kienböck disease, and 1 posttraumatic arthrosis.

Conclusion The average survival rate of our case series was 95.7% on a 4-year follow-up, 91.3% on a 6-year follow-up, and 69% on a 10-year follow-up. On our review, the QuickDASH score, pain, wrist extension range of motion, and grip strength were improved postoperatively. No difference was shown between preoperative and postoperative values for wrist flexion, pronation, and supination. The case series included a septic case, treated by arthrodesis, and three total wrist implants displacements, two of which were treated by carpal implant, and the remaining one was treated by arthrodesis.

Clinical Relevance The survival rate of the total wrist replacement implant Remotion was estimated to be 69%.
On the structure and photoluminescence of dislocations in silicon
Authors: Fedina L. I. , Gutakovskii A. K. , Shamirzaev T. S.
Published: August 2018

This paper presents a comparative analysis of the structure and photoluminescence (PL) of Si containing dislocations introduced by thermal shock or ion implantation. To study the structure of dislocation cores and their interaction with point defects, we used a high-resolution transmission mode during in situ electron irradiation in the JEM4000EX operating at 400 kV. An appropriate PL spectrum was obtained on dislocated Si after electron irradiation by an external pulse gun operating at 350 kV. This resulted only in an increase in the D2 line intensity that correlated with the formation of metastable interstitial defects on {001}, {111}, and {113} planes near various dislocation cores during in situ electron irradiation, regardless of their types. However, the D1 line relates to a core structure of a shuffle Lomer dislocation consisting of 5/7 atomic rings, which occurs when two shuffle 60° dislocations (so-called S1 type [Pizzagalli et al., Phys. Rev. Lett. 103, 065505 (2009)]) combine with each other in intersecting {111} planes in plastically deformed Si or when an extrinsic Frank partial dislocation transforms into a perfect one in an ion-implanted layer.
Density functional approximations for orbital energies and total energies of molecules and solids
Authors: Baerends Evert Jan
Published: August 2018

The relation of Kohn-Sham (KS) orbital energies to ionization energies and electron affinities is different in molecules and solids. In molecules, the local density approximation (LDA) and generalized gradient approximations (GGA) approximate the exact ionization energy (I) and affinity (A) rather well with self-consistently calculated (total energy based) ILDFA and ALDFA, respectively. The highest occupied molecular orbital (HOMO) energy and lowest unoccupied molecular orbital (LUMO) energy, however, differ significantly (by typically 4–6 eV) from these quantities, ϵHLDFA(mol)>−I(mol)≈−ILDFA(mol), ϵLLDFA(mol)<−A(mol)≈−ALDFA(mol). In solids, these relations are very different, due to two effects. The (almost) infinite extent of a solid makes the difference of orbital energies and (L)DFA calculated ionization energy and affinity disappear: in the solid state limit, ϵH(L)DFA(solid)=−I(L)DFA(solid) and ϵL(L)DFA(solid)=−A(L)DFA(solid). Slater’s relation ∂E/∂ni = ϵi for local density functional approximations (LDFAs) [and Hartree-Fock (HF) and hybrids] is useful to prove these relations. The equality of LDFA orbital energies and LDFA calculated −ILDFA and −ALDFA in solids does not mean that they are good approximations to the exact quantities. The LDFA total energies of the ions with a delocalized charge are too low, hence ILDFA(solid) < I and ALDFA(solid) > A, due to the local-approximation error, also denoted delocalization error, of LDFAs in extended systems. These errors combine to make the LDFA orbital energy band gap considerably smaller than the exact fundamental gap, ϵLLDFA(solid)−ϵHLDFA(solid)=ILDFA(solid)−ALDFA(solid)<I−A (the LDFA band gap problem). These results for density functional approximations are compared to exact KS and to HF and hybrids. For the exact KS HOMO energy, one has ϵHKS=−I. The exact KS LUMO energy does not approximate the experimental −A (neither in molecules nor in solids), but is considerably below, which is the main reason for the exact KS HOMO-LUMO energy gap being considerably below the fundamental gap I − A (the exact KS band gap problem).
Disorder enhanced thermal conductivity anisotropy in two-dimensional materials and van der Waals heterostructures
Authors: Kim Kyunghoon , He Jixiong , Ganeshan Banu , Liu Jun
Published: August 2018

Two-dimensional (2D) materials and van der Waals heterostructures can naturally function as directional heat spreaders in nanoelectronics due to their intrinsically anisotropic structure. In real nanoelectronic applications, disorders usually appear in those materials where their effects on anisotropic thermal conductivity are not well-understood. We built simple graphite-like material models and systematically incorporated mass disorder or structural disorder into the structures. The anisotropic thermal conductivities calculated by equilibrium molecular dynamics simulations show that mass disorder and stacking disorder can effectively and anisotropically tune the thermal conductivity of 2D materials and van der Waals heterostructures. Compared with pristine graphite, the through-plane thermal conductivity can be reduced up to two orders of magnitude by the through-plane mass disorder, and the thermal anisotropy ratio (i.e., the ratio of in-plane to through-plane thermal conductivity) can be enhanced more than ten times. We attribute this counter-intuitive result to the dramatic decrease in phonon group velocity in the through-plane direction. Our results can shed some light on the thermal management in electronics incorporating 2D materials and van der Waals heterostructures.
All-optical quantum thermometry based on spin-level cross-relaxation and multicenter entanglement under ambient conditions in SiC
Authors: Anisimov A. N. , Soltamov V. A. , Breev I. D. , Babunts R. A. , Mokhov E. N. , Astakhov G. V. , Dyakonov V. , Yakovlev D. R. , Suter D. , Baranov P. G.
Published: August 2018

All-optical thermometry technique based on the energy level cross-relaxation in atomic-scale spin centers in SiC is demonstrated. This technique exploits a giant thermal shift of the zero-field splitting for centers in the triplet ground state, S=1, undetected by photoluminescence (so called “dark” centers) coupling to neighbouring spin-3/2 centers which can be optically polarized and read out (“bright” centers), and does not require radiofrequency fields. EPR was used to identify defects. The width of the cross-relaxation line is almost an order of magnitude smaller than the width of the excited state level-anticrossing line, which was used in all-optical thermometry and which can not be significantly reduced since determined by the lifetime of the excited state. With approximately the same temperature shift and the same signal intensities as for excited state level-anticrossing, cross-relaxation signal makes it possible to increase the sensitivity of the temperature measurement by more than an order of magnitude. Temperature sensitivity is estimated to be approximately 10 mK/Hz1/2 within a volume about 1 μ3, allocated by focused laser excitation in a scanning confocal microscope. Using cross-relaxation in the ground states of “bright” spin-3/2 centers and “dark” S=1 centers for temperature sensing and ground state level anti-crossing of “bright” spin-3/2 centers an integrated magnetic field and temperature sensor with submicron space resolution can be implemented using the same spin system. The coupling of individually addressable “bright” spin-3/2 centers connected by a chain of “dark” S=1 spins, could be considered in quantum information processing and multicenter entanglement under ambient conditions.
Gyrokinetic particle simulation of electrostatic microturbulence with impurity ions
Authors: Wei Xishuo , Yang Hongwei , Li Shengming , Xiao Yong
Published: August 2018

Impurity is an important factor that can affect significantly turbulent transport in tokamaks. In order to study the impurity physics, we implement a new impurity module in the gyrokinetic particle simulation code GTC (Gyrokinetic Toroidal Code). With an improved numerical scheme, we expand the validity of gyrokinetic Poisson equation in the GTC to the short wavelength region, for both non-zonal and zonal parts of the perturbed Poisson equation. Verifications of this new scheme are carried out on the linear instability and zonal flow response. The linear simulation of the ion temperature gradient (ITG) instability including the impurity ions shows that the new Poisson solver can obtain the correct linear growth rate and frequency at the thermal ion gyro-radius scale. The residual zonal flow with impurities obtained via the new zonal flow solver is consistent with the numerical and analytical predictions in the large aspect-ratio limit. The nonlinear simulation of the ITG turbulence shows that the turbulent transport is significantly reduced by the impurity ions through decreasing the linear growth rate of the instability.
First-principles study of thermoelectric properties of blue phosphorene
Authors: Liu Zeyu , Morales-Ferreiro J. O. , Luo Tengfei
Published: August 2018

Thermoelectric behavior involving coupled electron and phonon transport properties of monolayer blue phosphorene is studied using the Boltzmann transport equation and first-principles calculations based on the density functional perturbation theory and Wannier interpolation. We find that the maximum figure of merit, ZT, of 0.016 is achievable in n-type blue phosphorene at 500 K with a positive gate voltage of 0.948 V. The relatively low ZT value is due to the large lattice thermal conductivity, which is around 130 W/mK at 300 K. This large lattice thermal conductivity is attributed to the small three-phonon scattering phase space due to the presence of a large phonon frequency gap in the dispersion. The relatively large power factor coupled with large thermal conductivity suggests that blue phosphorene can be ideal for active cooling applications. Nanostructuring with a characteristic length of 10 nm, which should not impact electron transport, is promising to reduce lattice thermal conductivity significantly and help increase ZT to the order of magnitude of 1. Our findings may offer perspectives on the potential applications of blue phosphorene in nanoelectronics and thermoelectrics.
Cyclotron acceleration of energetic ions by plasma blobs
Authors: Marchenko V. S. , Reznik S. N.
Published: August 2018

Due to their intrinsic vertical polarization induced by magnetic drifts, outward propagating plasma blobs (filaments), which arise at the nonlinear stage of the pedestal collapse, can serve as natural gaps for cyclotron acceleration of the fast ions having gyro-radius larger than the blob size transverse to magnetic field. Acceleration time is determined by the drift motion of the fast ion guiding center. For the electron temperature at the separatrix Tes ∼ 100 eV, even one blob encountered by the fast ion in the scrape-off layer can increase its energy by 50–60 keV above the injection energy. The possible relation of this result with observations in the ASDEX Upgrade tokamak is discussed.
Glyphosate removal from water by functional three-dimensional graphene aerogels
Authors: Ding Chaofan , Wang Xueying , Liu Hao , Li Yue , Sun Yuanling , Lin Yanna , Sun Weiyan , Zhu Xiaodong , Dai Yuxue , Luo Chuannan
Published: August 2018

Environmental contextGlyphosate is a non-selective and widely used herbicide commonly found as a contaminant in water. This work reports the use of functional graphene aerogels prepared with carboxymethyl chitosan and graphene oxide for the efficient adsorption and removal of glyphosate present in water samples. The procedure has potential to successfully treat water bodies contaminated with glyphosate.
AbstractThree-dimensional carboxymethyl chitosan (CM-CS)–graphene aerogels (CM-CS@GA) were prepared through an integration strategy of a carboxylation process and freeze drying technology for efficient glyphosate removal from water. The structure, surface properties, morphology and crystal phase of the prepared CM-CS@GA composites were characterised using SEM, TEM, XRD, FT-IR and BET. The adsorption behaviour of glyphosate in aqueous solution on CM-CS@GA was systematically investigated. The results show that with the advantages of high surface area, and abundant hydroxyl and carboxyl groups of CM-CS@GA, glyphosate can be easily and rapidly extracted from the water. The adsorption equilibrium of CM-CS@GA for glyphosate correspond to a Langmuir isotherm, the maximum adsorption capacity can reach to 578.0 mg g−1, and the novel adsorbent exhibited a better glyphosate removal efficiency in solutions with low pH. The exhausted CM-CS@GA composites could be regenerated by NaOH solution for repeated use without any significant capacity loss, where the adsorbed glyphosate was effectively desorbed into the solution. These results provide evidence to further validate that CM-CS@GA composites would be of considerable potential in the removal of glyphosate from contaminated waters.
Biocorrosion of materials and sick building syndrome
Authors: Ilinskaya Olga , Bayazitova Alina , Yakovleva Galina
Published: August 2018

The problem of biological damage of mineral building materials and structures based on them is multifaceted and covers all types of industry. The most destructive biocorrosion impacts are on building materials in cities with a large water area. Various types of microorganisms, including pathogens, and especially the filamentous fungi of the genera Aspergillus, Penicillium, Trichoderma, etc., occupy the surfaces of mineral building materials, cause their destruction, disturb the ecological balance of cities and endanger the human health. The term ‘sick building syndrome' (SBS) is used to describe a situation when the residents of a building experience acute health- or comfort-related effects that seem to be linked directly to the time spent in the building wherein no specific illness or cause can be identified. Biological contaminants, in particular micromycetes, can present one of the possible causes of SBS. Here, we assessed the biodeterioration level of structural materials on the basis of fine-grained concrete widely used in construction practice and architecture. First, we determined the strength characteristics of the material that has been biologically damaged; second, we identified the damaging micromycetes and analysed their metabolic activity related both to the induction of biocorrosion and to the impacts of fungi on human health. Applying a new integrated approach, which combines methods of molecular microbiology and genetic toxicology with standard methods for determining the strength of building structures, we confirmed the relation between biodestructive and pathogenic properties of micromycete isolates.
Quantum control of phase fluctuations in semiconductor lasers
Authors: Santis Christos T. , Vilenchik Yaakov , Satyan Naresh , Rakuljic George , Yariv Amnon
Published: August 2018

Significance

The semiconductor laser, arguably the most versatile member of the family of lasers, has become a technological staple of a massively interconnected, data-driven world, with its spectral purity (i.e., temporal coherence) an increasingly important figure of merit. The present work describes a conceptually fundamental “recipe” for the enhancement of coherence, predicated on direct control of the coherence-limiting process itself, the field–matter interaction. As such, it is inherently adaptable and technologically scalable. As photonic materials and fabrication techniques continue to improve, the described approach has the potential of serving as a roadmap for major and sustained improvements in coherence. With experimentally demonstrated coherence limited at 1 kHz in this work, we envision “deep” sub-kilohertz-level coherence to be soon within reach.