In-situ leading-edge-induced damages of melting and cracking on W/Cu monoblocks as divertor target during long-term operations in EAST

2021 ◽  
Author(s):  
Dahuan Zhu ◽  
Changjun Li ◽  
Binfu Gao ◽  
Rui Ding ◽  
Bao Guo Wang ◽  
...  
Keyword(s):  
Thermal Loading ◽  
Leading Edge ◽  
Fatigue Cracking ◽  
Ccd Camera ◽  
Critical Issue ◽  
Mechanical Analysis ◽  
Maximum Temperature ◽  
Leading Edges

Abstract Leading-edge-induced thermal loading effect due to assembly tolerance between neighboring castellated plasma facing components is a critical issue in fusion devices. Actively-cooled ITER-like W/Cu monoblocks were successfully installed for upper divertor target in EAST which significantly increases the ability of divertor power exhaust. The misalignment between neighboring monoblocks was formed inevitably during manufacturing and assembly processes, providing a possibility to demonstrate the leading-edge-induced thermal damages. Indeed, the leading-edge-induced melting phenomena of W/Cu monoblocks on upper divertor targets were observed during plasma discharges with a large number of droplets ejected from divertor target using CCD camera, which were also identified at the leading edges of W/Cu monoblocks. Not only that, but also many macro cracks with width of ~70 m and depth of < 5 mm along radial and toroidal directions were also found universally at the leading edges of W/Cu monoblocks by post-mortem inspection after plasma campaigns. Thermal-mechanical analysis by means of the finite element simulation demonstrated that the maximum temperature could reach W melting point under current projected heat load of ~3 MWm-2 on flat top surface with large misalignment up to 3 mm at the leading edges. Meanwhile, the high temperature also induced high thermal stress and strain concentration at the center of leading edges, at which the thermal fatigue cracking could be initially generated. Such kind of cracks at leading edges on W/Cu monoblocks may be unavoidable due to the long-term pulsed fatigue effects. However, the influence of these cracks seems to be acceptable thanks to the limited propagated distance by self-castellation effect, which still need long-term tracking. The in-situ leading-edge-induced damages of melting and cracking on W/Cu monoblocks of EAST upper divertor target provide significant reference to understand the leading-edge-induced thermal effect in ITER and future fusion devices.

A Heat Plate Leading Edge for Hypersonic Vehicles

2008 ◽  
Author(s):  
Scott D. Kasen ◽  
Doug T. Queheillalt ◽  
Craig A. Steeves ◽  
Anthony G. Evans ◽  
Haydn N. G. Wadley
Keyword(s):  
Heat Flux ◽  
Low Temperature ◽  
Heat Pipe ◽  
Thermal Management ◽  
Leading Edge ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Hypersonic Vehicles ◽  
Vapor Flow ◽  
Leading Edges

The intense thermal flux at the leading edges of hypersonic vehicles (traveling at Mach 5 and greater) requires creative thermal management strategies to prevent damage to leading edge components. Carbon fiber composites and/or ablative coatings have been widely utilized to mitigate the effects of the impinging heat flux. This paper focuses on an alternative, metallic leading edge heat pipe concept which combines efficient structural load support and thermal management. The passive concept is based on high thermal conductance heat pipes which redistribute the high heat flux at the leading edge stagnation point through the evaporation, vapor flow, and condensation of a working fluid to a location far from the heat source. Structural efficiency is provided by a sandwich construction using an open-cell core that also allows for vapor flow. A low temperature proof-of-concept copper–water system has been investigated by experimentation. Measuring of the axial temperature profile indicates effective spreading of thermal energy, a lowering of the maximum temperature and reduced overall thermal gradient compared to a non-heat pipe leading edge. A simple transient analytical model based on lumped thermal capacitance theory is compared with the experimental results. The low-temperature prototype shows potential for higher temperature metallic leading edges that can withstand the hypersonic thermo-mechanical environment.

scholarly journals Application and verification of a multivariate real-time early warning method for rainfall-induced landslides: implication for evolution of landslide-generated debris flows

Landslides ◽  
2020 ◽  
Vol 17 (10) ◽  
pp. 2409-2419
Author(s):  
Zongji Yang ◽  
Liyong Wang ◽  
Jianping Qiao ◽  
Taro Uchimura ◽  
Lin Wang
Keyword(s):  
Debris Flow ◽  
Real Time ◽  
Early Warning ◽  
Early Warning Systems ◽  
Mechanical Analysis ◽  
Warning Systems ◽  
Physical Mechanisms ◽  
New Strategy

Abstract Rainfall-induced landslides are a frequent and often catastrophic geological disaster, and the development of accurate early warning systems for such events is a primary challenge in the field of risk reduction. Understanding of the physical mechanisms of rainfall-induced landslides is key for early warning and prediction. In this study, a real-time multivariate early warning method based on hydro-mechanical analysis and a long-term sequence of real-time monitoring data was proposed and verified by applying the method to predict successive debris flow events that occurred in 2017 and 2018 in Yindongzi Gully, which is in Wenchuan earthquake region, China. Specifically, long-term sequence slope stability analysis of the in situ datasets for the landslide deposit as a benchmark was conducted, and a multivariate indicator early warning method that included the rainfall intensity-probability (I-P), saturation (Si), and inclination (Ir) was then proposed. The measurements and analysis in the two early warning scenarios not only verified the reliability and practicality of the multivariate early warning method but also revealed the evolution processes and mechanism of the landslide-generated debris flow in response to rainfall. Thus, these findings provide a new strategy and guideline for accurately producing early warnings of rainfall-induced landslides.

scholarly journals RELATING FLEXIBLE PAVEMENT ACCEPTANCE CRITERIA TO PERFORMANCE USING MEPDG SIMULATIONS AND PIECEWISE CUBIC SPLINE INTERPOLATION / LANKSČIŲJŲ DANGŲ ATRANKOS KRITERIJŲ SUSIEJIMAS NAUDOJANT MEPDG MODELIUS IR DALINĘ KUBINĘ SPLAININĘ INTERPOLIACIJĄ

2012 ◽  
Vol 18 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Anshu Manik ◽  
Karim Chatti ◽  
Kasthurirangan Gopalakrishnan
Keyword(s):  
Spline Interpolation ◽  
Fatigue Cracking ◽  
Flexible Pavement ◽  
Pavement Performance ◽  
Air Voids ◽  
Field Investigations ◽  
The Relationship

The performance of the highway system is inevitably linked to its quality of design and construction. To control the quality of construction, elaborate Quality Assurance (QA) programs have been developed by highway agencies based on statistical sampling and acceptance procedures to ensure that the work is in accordance with the plans and specifications. The QA procedure is intended to ensure that the constructed pavement would perform well during its design life. However, numerous field investigations and research studies over the years have identified a gap in our understanding of the relationship between the QA test results and pavement performance (fatigue cracking, rutting, etc.). This paper is intended to present the framework for developing an understanding of the relationship between QA tests and flexible pavement performance, which is essential for developing Performance Related Specifications (PRS). In the first part of the paper, the Michigan Department of Transportation's (MDOT) QA program and Long-Term Pavement Performance (LTPP) databases were used to empirically investigate any relationship between key QA variables and various pavement performance measures. In the second part of the paper, the Mechanistic-Empirical Pavement Design Guide (MEPDG) software was used together with an accurate and efficient interpolation technique to develop many simulations for the purpose of showing the effect of variability in QA parameters including plant air voids, in-situ density and asphalt content on flexible pavement performance. Santrauka Greitkelių sistemos darbas (funkcionavimas) yra neišvengiamai susijęs su jo projektavimo ir statybų kokybe. Greitkelių agentūros, remdamosi statistinėmis atrankos ir ėmimo procedūromis, parengė kokybės užtikrinimo (KU arba QA) programas, kad būtų kontroliuojama statybų kokybė ir užtikrinamas darbas pagal planus ir specifikacijas. KU (QA) procedūra siekiama užtikrinti, kad pagaminta danga gerai funkcionuotų projekte nurodytą laiką. Tačiau metams einant, atlikus daugybę natūrinių ir mokslinių tyrimų, buvo nustatytas didelis santykio tarp KU (QA) bandymų rezultatų ir dangos darbo (funkcionavimo) (plyšių atsiradimo dėl nuovargio, provėžų ir kt.) vertinimo skirtumas. Šiame darbe skatinama plėtoti supratimą apie ryšius tarp KU (QA) bandymų ir lanksčiųjų dangų funkcionavimo, kuris yra nepaprastai svarbus kuriant su darbu (funkcionavimu) susijusias specifikacijas (PRS). Pirmoje darbo dalyje buvo naudojamos Mičigano transporto departamento (MDOT) KU (QA) programos ir ilgalaikės dangos darbo (funkcionavimo) (LTPP) duomenų bazės, siekiant empiriškai ištirti bet kuriuos santykius tarp pagrindinių KU (QA) kintamųjų ir įvairių dangų darbo matavimų. Antroje darbo dalyje buvo naudojama mechanistinio ir empirinio dangų projektavimo vadovo (MEPDG) programinė įranga kartu su tikslia ir efektyvia interpoliacijos technika, siekiant sukurti modelius, kuriuose perteiktas KU (QA) parametrų kintamumo poveikis lanksčiųjų dangų funkcionavimui, įskaitant augalų oro ertmes, vietinį tankį ir asfalto sandarą.

Brief summary of Kleť photographic search programme for minor planets

1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec
Keyword(s):  
Ccd Camera ◽  
Minor Planet ◽  
Minor Planets ◽  
Main Belt

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.

scholarly journals Global soil moisture data derived through machine learning trained with in-situ measurements

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sungmin O. ◽  
Rene Orth
Keyword(s):  
Machine Learning ◽  
Soil Moisture ◽  
Large Scale ◽  
Short Term Memory ◽  
Temporal Dynamics ◽  
Soil Moisture Data ◽  
Wide Range ◽  
Global Soil

AbstractWhile soil moisture information is essential for a wide range of hydrologic and climate applications, spatially-continuous soil moisture data is only available from satellite observations or model simulations. Here we present a global, long-term dataset of soil moisture derived through machine learning trained with in-situ measurements, SoMo.ml. We train a Long Short-Term Memory (LSTM) model to extrapolate daily soil moisture dynamics in space and in time, based on in-situ data collected from more than 1,000 stations across the globe. SoMo.ml provides multi-layer soil moisture data (0–10 cm, 10–30 cm, and 30–50 cm) at 0.25° spatial and daily temporal resolution over the period 2000–2019. The performance of the resulting dataset is evaluated through cross validation and inter-comparison with existing soil moisture datasets. SoMo.ml performs especially well in terms of temporal dynamics, making it particularly useful for applications requiring time-varying soil moisture, such as anomaly detection and memory analyses. SoMo.ml complements the existing suite of modelled and satellite-based datasets given its distinct derivation, to support large-scale hydrological, meteorological, and ecological analyses.

scholarly journals A Study of UVER in Santiago, Chile Based on Long-Term In Situ Measurements (Five Years) and Empirical Modelling

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 368
Author(s):  
Lisdelys González-Rodríguez ◽  
Amauri Pereira de Oliveira ◽  
Lien Rodríguez-López ◽  
Jorge Rosas ◽  
David Contreras ◽  
...  
Keyword(s):  
Urban Areas ◽  
Solar Spectrum ◽  
Sun Exposure ◽  
Great Accuracy ◽  
In Situ Measurements ◽  
Uv Index ◽  
Empirical Modelling ◽  
The People

Ultraviolet radiation is a highly energetic component of the solar spectrum that needs to be monitored because is harmful to life on Earth, especially in areas where the ozone layer has been depleted, like Chile. This work is the first to address the long-term (five-year) behaviour of ultraviolet erythemal radiation (UVER) in Santiago, Chile (33.5° S, 70.7° W, 500 m) using in situ measurements and empirical modelling. Observations indicate that to alert the people on the risks of UVER overexposure, it is necessary to use, in addition to the currently available UV index (UVI), three more erythema indices: standard erythemal doses (SEDs), minimum erythemal doses (MEDs), and sun exposure time (tery). The combination of UVI, SEDs, MEDs, and tery shows that in Santiago, individuals with skin types III and IV are exposed to harmfully high UVER doses for 46% of the time that UVI indicates is safe. Empirical models predicted hourly and daily values UVER in Santiago with great accuracy and can be applied to other Chilean urban areas with similar climate. This research inspires future advances in reconstructing large datasets to analyse the UVER in Central Chile, its trends, and its changes.

scholarly journals In-Situ Annealed Ti3C2Tx MXene Based All-Solid-State Flexible Zn-Ion Hybrid Micro Supercapacitor Array with Enhanced Stability

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
La Li ◽  
Weijia Liu ◽  
Kai Jiang ◽  
Di Chen ◽  
Fengyu Qu ◽  
...  
Keyword(s):  
High Energy ◽  
High Rate ◽  
High Energy Density ◽  
Electrochemical Performances ◽  
Integrated Electronics ◽  
Long Term Stability ◽  
Hybrid Supercapacitors ◽  
Portable Electronics

AbstractZn-ion hybrid supercapacitors (SCs) are considered as promising energy storage owing to their high energy density compared to traditional SCs. How to realize the miniaturization, patterning, and flexibility of the Zn-ion SCs without affecting the electrochemical performances has special meanings for expanding their applications in wearable integrated electronics. Ti3C2Tx cathode with outstanding conductivity, unique lamellar structure and good mechanical flexibility has been demonstrated tremendous potential in the design of Zn-ion SCs, but achieving long cycling stability and high rate stability is still big challenges. Here, we proposed a facile laser writing approach to fabricate patterned Ti3C2Tx-based Zn-ion micro-supercapacitors (MSCs), followed by the in-situ anneal treatment of the assembled MSCs to improve the long-term stability, which exhibits 80% of the capacitance retention even after 50,000 charge/discharge cycles and superior rate stability. The influence of the cathode thickness on the electrochemical performance of the MSCs is also studied. When the thickness reaches 0.851 µm the maximum areal capacitance of 72.02 mF cm−2 at scan rate of 10 mV s−1, which is 1.77 times higher than that with a thickness of 0.329 µm (35.6 mF cm−2). Moreover, the fabricated Ti3C2Tx based Zn-ion MSCs have excellent flexibility, a digital timer can be driven by the single device even under bending state, a flexible LED displayer of “TiC” logo also can be easily lighted by the MSC arrays under twisting, crimping, and winding conditions, demonstrating the scalable fabrication and application of the fabricated MSCs in portable electronics.

scholarly journals Poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) Copolymers for the Formulation of In Situ Forming Depot Long-Acting Injectables

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 605
Author(s):  
Marie-Emérentienne Cagnon ◽  
Silvio Curia ◽  
Juliette Serindoux ◽  
Jean-Manuel Cros ◽  
Feifei Ng ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Surface Erosion ◽  
Sustained Delivery ◽  
Trimethylene Carbonate ◽  
Poly Ethylene Glycol ◽  
In Situ Forming ◽  
Poly Ethylene ◽  
Long Acting

This article describes the utilization of (methoxy)poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) ((m)PEG–PTMC) diblock and triblock copolymers for the formulation of in situ forming depot long-acting injectables by solvent exchange. The results shown in this manuscript demonstrate that it is possible to achieve long-term drug deliveries from suspension formulations prepared with these copolymers, with release durations up to several months in vitro. The utilization of copolymers with different PEG and PTMC molecular weights affords to modulate the release profile and duration. A pharmacokinetic study in rats with meloxicam confirmed the feasibility of achieving at least 28 days of sustained delivery by using this technology while showing good local tolerability in the subcutaneous environment. The characterization of the depots at the end of the in vivo study suggests that the rapid phase exchange upon administration and the surface erosion of the resulting depots are driving the delivery kinetics from suspension formulations. Due to the widely accepted utilization of meloxicam as an analgesic drug for animal care, the results shown in this article are of special interest for the development of veterinary products aiming at a very long-term sustained delivery of this therapeutic molecule.

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