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Mantle avalanches in a Venus-like stagnant lid planet

Earth and Planetary Physics 2024年第5期8卷 686-702页

作者： Madeleine C.Kerr dave r.stegman Institute of Geophysics and Planetary Physics Scripps Institution of OceanographyUniversity of CaliforniaSan DiegoLa JollaCAUSA

Stagnant lid planets are characterized by a globe-encircling,conducting lid that is thick and strong,which leads to reduced global surface heat ***,the mantles of such planets can have warmer interiors than Earth,and interestingly,a pyrolitic mantle composition under warmer conditions is predicted to have a distinctly different mantle transition zone compared to the present-day Earth(Hirose,2002;Stixrude and Lithgow-Bertelloni,2011;Ichikawa et al.,2014;Dannberg et al,2022).Instead of olivine primarily transforming into its higher-pressure polymorphs such as wadsleyite and then ringwoodite,at pressures corresponding to 410 km and 520 km depth in Earth,respectively,it instead transforms into a mineral assemblage of wadsleyite,majorite,and ferropericlase(WMF),and then to majorite+ferropericlase(MF),before finally transforming into bridgmanite at pressures corresponding to 660 km depth in Earth(Stixrude and Lithgow-Bertelloni,2011;Ichikawa et al.,2014).Convective motions in stagnant lid planets are dominated by small-scale instabilities(cold drips)forming within the mobile rheological sublayer under the rigid *** ASPECT and a thermodynamic model of a pyrolitic mantle composition generated by HeFESTo,we show that under certain conditions,the small drips can pond atop the WMF-MF mineral phase *** barrier to convective flow arises from the WMF mineral phase assemblage having an effective negative thermal expansivity(Stixrude and Lithgow-Bertelloni,2022).Although large-scale downwellings that typically occur within mobile lid planets are able to pass through the WMF zone without difficulty(Dannberg et al.,2022;Li rP et al.,2024),the smaller and less negatively buoyant nature of downwelling drips in stagnant lid planets are more susceptible to these effects,which leads to an ephemeral layering of the *** numerical models show that in stagnant lid planets with mantle potential temperatures that exceed 1900 K,the smaller,cold drips from t

关键词： Venus mantle avalanches numerical modelling phase transitions

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Flexural strength of fused filament fabricated (FFF) PLA parts on an open-source 3D printer

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Advances in Manufacturing 2018年第4期6卷 430-441页

作者： Shilpesh r. rajpurohit Harshit K. dave Department of Mechanical Engineering SV National Institute of Technology Surat Gujarat 395007 India

Fused filament fabrication (FFF) has been widely used to develop prototypes as well as functional parts owing to its capability for creating parts with complex geometries in a short time without the specific requirement of tooling. The mechanical properties of parts produced by FFF exhibit 70%-80% of the mechanical properties of parts produced by injection molding. The mechanical properties of FFF-produced parts are primarily dependent on the selection of various process variables. The mechanical properties of the part can be enhanced through the proper selection of process variables. In the present experimental investigation, the effects of the process variables, viz. raster angle, layer height, and raster width on the flexural properties of FFF-printed polylactic acid (PLA) is studied. The result shows that flexural strength is primarily influenced by layer height followed by raster angle. The sample printed with 100-μm layer height and 0° raster angle exhibits a higher tensile strength. Further, the microscopic examination of the deformed specimen is performed to understand the mode of failure. Specimens printed at different raster angles show different modes of failure.

关键词： Fused filament fabrication (FFF) Polylactic acid (PLA) raster angle Layer height raster width Flexural strength

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The Use of 'In Process' Monitoring Equipment in Heat Treatment Today

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材料热处理学报 2004年第5期25卷 591-596页

作者： dave Plester Datapaq limited Cambridge CB4 OGU UK

This paper looks at how in-process temperature monitoring systems are being increasingly used in heat treatment applications such as surface hardening, annealing, normalizing, tempering etc. We look at the basic equipment required to successfully monitor from within a furnace and how developments such as rF transmission have enhanced the effectiveness of profiling trials to the point where on line adjustments to furnace conditions can be seen and analyzed in real time. We examine how continuous processes can benefit from this type of monitoring and also how routine operations such as furnace surveying in batch furnaces can benefit greatly from in-process monitoring. Advances in software are also considered, showing how packages are now designed to speed up the processing of data in day to day heat treatment operations.

关键词：热处理温度监测器射频传输剖面测量

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Antioxidant potential and physicochemical properties of protein hydrolysates from body parts of North Atlantic sea cucumber(Cucumaria frondosa)

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Food Production, Processing and Nutrition 2021年第1期3卷 48-69页

作者： Tharindu r.L.Senadheera Deepika dave Fereidoon Shahidi Department of Biochemistry Memorial University of NewfoundlandSt.John’sNL A1B 3X9Canada Marine Bioprocessing Facility Centre of Aquaculture and Seafood DevelopmentFisheries and Marine InstituteMemorial University of NewfoundlandSt.John’sNL A1C 5R3Canada

Protein hydrolysates were prepared from North Atlantic sea cucumber(Cucumaria frondosa)body wall(BW),and processing by-product flower(FL)and internal organs(IN).Sea cucumber proteins from these three tissues were hydrolysed with selected endopeptidases and *** enzymes used were Alcalase(A),and Corolase(C)as endopeptidases and Flavourzyme(F)with both endo-and exopeptidase *** were employed individually or in combination under controlled *** hydrolysates so prepared were subsequently analysed for their antioxidant potential and functionalities in food systems for the first *** treated with the combination of A and F exhibited the highest radical scavenging activity against DPPH and ABTS *** highest metal chelation activity was observed for samples hydrolysed with the combination of enzymes(C+F and A+F).All treatments inhibited beta-carotene bleaching in an oil-in-water emulsion and TBArS production in a meat model *** addition,sea cucumber protein hydrolysates were more than 75%soluble over a pH range of 2–*** proteins were also effective in enhancing water holding capacity in a meat model system compared to their untreated *** amino acids of sea cucumber protein hydrolysates had desirable profiles with glutamic acid as the predominant component in samples *** findings demonstrate the desirable functionalities of hydrolysates from North Atlantic sea cucumber and their potential for use as functional food ingredients.

关键词： Sea cucumber Protein hydrolysates Antioxidant activity Physicochemical properties

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IQr-based approach for DDoS detection and mitigation in SDN

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Defence Technology（防务技术） 2023年第7期25卷 76-87页

作者： rochak Swami Mayank dave Virender ranga Department of Computer Engineering National Institute of TechnologyKurukshetraIndia Department of Information Technology Delhi Technological UniversityDelhiIndia

Software-defined networking(SDN) is a trending networking paradigm that focuses on decoupling of the control logic from the data plane. This decoupling brings programmability and flexibility for the network management by introducing centralized infrastructure. The complete control logic resides in the controller, and thus it becomes the intellectual and most important entity of the SDN infrastructure. With these advantages, SDN faces several security issues in various SDN layers that may prevent the growth and global adoption of this groundbreaking technology. Control plane exhaustion and switch buffer overflow are examples of such security issues. Distributed denial-of-service(DDoS) attacks are one of the most severe attacks that aim to exhaust the controller’s CPU to discontinue the whole functioning of the SDN network. Hence, it is necessary to design a quick as well as accurate detection scheme to detect the attack traffic at an early stage. In this paper, we present a defense solution to detect and mitigate spoofed flooding DDoS attacks. The proposed defense solution is implemented in the SDN controller. The detection method is based on the idea of an statistical measure — Interquartile range(IQr). For the mitigation purpose, the existing SDN-in-built capabilities are utilized. In this work, the experiments are performed considering the spoofed SYN flooding attack. The proposed solution is evaluated using different performance parameters, i.e., detection time, detection accuracy, packet_in messages, and CPU utilization. The experimental results reveal that the proposed defense solution detects and mitigates the attack effectively in different attack scenarios.

关键词： SDN DdoS IQr Controller CPU utilization Packet_in

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Microstructural Characteristics and Mechanical Properties of Low-Alloy, Medium-Carbon Steels After Multiple Tempering

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Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 74-88页

作者： Erfan Abbasi Quanshun Luo dave Owens Materials and Engineering research Institute Sheffield Hallam University Tyzack Machine Knives Ltd

The microstructure and mechanical properties of NiCrMoV-and NiCrSi-alloyed medium-carbon steels were investigated after multiple tempering. After austenitising, the steels were hardened by oil quenching and subsequently double or triple tempered at temperatures from 250 to 500 °C. The samples were characterised using scanning electron microscopy and X-ray diffraction, while the mechanical properties were evaluated by Vickers hardness testing, V-notched Charpy impact testing and tensile testing. The results showed that the retained austenite was stable up to 400 °C and the applied multiple tempering below this temperature did not lead to a complete decomposition of retained austenite in both steels. It was also found that the microstructure, hardness and impact toughness varied mainly as a function of tempering temperature,regardless of the number of tempering stages. Moreover, the impact toughness of NiCrMoV steel was rather similar after single/triple tempering at different temperatures, while NiCrSi steel exhibited tempered martensite embrittlement after single/double tempering at 400 °C. The observed difference was mainly attributed to the effect of precipitation behaviour due to the effect of alloying additions in the studied steels.

关键词： Medium-carbon steels Multiple tempering Alloying addition Mechanical properties retained austenite Precipitation behaviour

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Intelligent transportation systems for smart cities:a progress review

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Science China(Information Sciences) 2012年第12期55卷 2908-2914页

作者： COOPEr dave E State Key Laboratory of Software Development Environment School of Computer Science and EngineeringBeihang University

To better meet the challenge of providing effective,low-cost,energy efficient transport services,the concept of intelligent transport systems(ITS) has been proposed and lauded as an innovative and promising solution for next generation transport *** this paper,the progress of ITS research around the world is briefly reviewed and current challenges are outlined,thereby offering further insight into ITS development for all researchers in this area.

关键词： intelligent transportation systems traffic information smart city

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Functional and physiochemical properties of protein isolates from different body parts of North Atlantic sea cucumber (Cucumaria frondosa)

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Food Bioscience 2023年第2期52卷 1379-1388页

作者： Tharindu r.L.Senadheera Abul Hossain Deepika dave Fereidoon Shahidi Department of Biochemistry Memorial University of NewfoundlandSt.John’sNLA1C 5S7Canada Marine Bioprocessing Facility Centre of Aquaculture and Seafood DevelopmentFisheries and Marine InstituteMemorial University of NewfoundlandSt.John’sNLA1C 5R3Canada

Sea cucumbers are a good source of proteins and essential amino *** this study,protein isolates were recovered from North Atlantic sea cucumber(Cucumaria frondosa)body wall(BWI)and processing by-products,including flower(FLI)and internal organs(INI),using the pH-shift *** properties of protein isolates were investigated and compared with those of soy protein isolates(SPI).All protein isolates exhibited a typical U-shaped solubility curve showing a minimum solubility at their isoelectric ***,emulsification and foaming properties of the sea cucumber protein isolates were also pH-dependent and corresponded with their *** highest water holding capacity was observed in FLI,whereas SPI showed the lowest oil holding capacity among all tested protein *** cucumber protein isolates exhibited significantly higher(prface hydrophobicity and relatively lower sulfhydryl(SH)group and disulfide(SS)bonds compared to *** addition,Fourier transform infrared(FTIr)spectra of sea cucumber protein isolates exhibited unique absorption peaks related to their secondary *** acid profiles of sea cucumber protein isolates revealed that they could be used as rich and complete sources of essential amino *** findings suggest that Atlantic sea cucumber protein isolates could serve as functional food ingredients.

关键词： Sea cucumber Cucumaria frondosa Protein isolates Functional properties

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Constitutive model for monotonic and cyclic responses of loosely cemented sand formations

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Journal of rock Mechanics and Geotechnical Engineering 2018年第4期10卷 740-752页

作者： Mojtaba rahimi dave Chan Alireza Nouri Department of Mechanical Engineering Azad UniversityKhomeinishahr BranchIsfahanIran Department of Civil and Environmental Engineering University of AlbertaEdmontonT6G 2W2Canada China Three Gorges University YichangChina

This paper presents a model to simulate the monotonic and cyclic behaviours of weakly cemented *** elastoplastic constitutive model within the framework of bounding surface plasticity theory is adopted to predict the mechanical behaviour of soft sandstone under monotonic and cyclic loadings. In this model, the loading surface always passes through the current stress state regardless of the type of loading. Destruction of the cementation bonds by plastic deformation in the model is considered as the primary mechanism responsible for the mechanical degradation of loosely cemented sands/weak *** model cyclic response, the unloading plastic and elastic moduli are formulated based on the loading/reloading plastic and elastic moduli. The proposed model was implemented in FLAC2D and evaluated against laboratory triaxial tests under monotonic and cyclic loadings, and the model results agreed well with the experimental observations. For cyclic tests, hysteresis loops are captured with reasonable accuracy.

关键词： Cyclic loading Monotonic loading Cemented sand Plasticity Constitutive model

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Changes in sleep parameters following biomimetic oral appliance therapy: A case report

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World Journal of Clinical Cases 2021年第10期9卷 2312-2319页

作者： G dave Singh Shamshudin Kherani Institute of Craniofacial Sleep Medicine Vivos TherapeuticsInc.Highlands RanchCO 80129United States Dental Clinic Kherani Dental at AspenCalgary T3H0N6Canada

BACKGrOUND Mandibular advancement devices(MADs)are used to treat mild to moderate obstructive sleep apnea(OSA),but there is a risk that the underlying condition can worsen in the ***,this case report is based on biomimetic oral appliance therapy as an alternative to MADs,which was found to be beneficial in the treatment of a case with severe *** SUMMArY An overnight sleep study was undertaken in a 50-year-old male with excessive daytime sleepiness that lead to a diagnosis of severe OSA as the apnea-hypopnea index(AHI)was found to be 32.8/*** the patient was unable to comply with continuous positive airway pressure therapy and declined surgical intervention,treatment with a MAD was *** 10 years later,another sleep study was performed with no MAD in the mouth,which revealed an AHI of 67.9/*** view of the deterioration in sleep quality,the patient sought alternative treatment and elected on biomimetic oral appliance therapy,using a mandibular repositioning nighttime appliance(mrNA appliance®,Vivos Therapeutics,Inc.,United States).After 10 mo,another sleep study was performed with no device in the patient’s mouth,which revealed an AHI of 11.8/h,a mean oxygen saturation of 94%and a mean oxygen desaturation index of 5.3%while *** analysis of the pre-and post-treatment study models of the upper jaw showed localized size increases of 15%-17%in the premolar regions and 15%-23%in the molar *** In adults with severe OSA that are unable to accept continuous positive airway pressure or surgical treatment,biomimetic oral appliance therapy may be preferable over MADs since biomimetic oral appliance therapy may be able to prevent worsening of sleep parameters by remodeling the nasomaxillary ***-term follow up studies are required to verify these novel findings.

关键词： Obstructive sleep apnea Biomimetic oral appliance therapy Continuous positive airway pressure Mandibular advancement device Case report

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