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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 Oceanography University of California

Stagnant lid planets are characterized by a globe-encircling, conducting lid that is thick and strong, which leads to reduced global surface heat flows. Consequently, 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 to410 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 lid. Using 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 transition. The 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 mantle. Our numerical models show that in stagnant lid planets with mantle potential temperatures that exceed

关键词： Venus mantle avalanches numerical modelling phase transitions

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Answering calls for rigorous health equity research:a cross-sectional study leveraging electronic health records for data disaggregation in Latinos

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Family Medicine and Community Health 2023年第2期11卷 9-17页

作者： John Heintzman Dang Dinh Jennifer A Lucas Elena Byhoff Danielle M Crookes Ayana April-Sanders Jorge Kaufmann dave boston Audree Hsu Sophia Giebultowicz Miguel Marino Family Medicine Oregon Health&Science UniversityPortlandOregonUSA Department of Medicine University of MassachusettsBostonMassachusettsUSA College of Social Sciences and Humanities Northeastern UniversityBostonMassachusettsUSA Rutgers School of Public Health PiscatawayNew JerseyUSA OCHIN PortlandOregonUSA California University of Science and Medicine ColtonCaliforniaUSA

Introduction Country of birth/nativity information may be crucial to understanding health equity in Latino populations and is routinely called for in health services literature assessing cardiovascular disease and risk,but is not thought to co-occur with longitudinal,objective health information such as that found in electronic health records(EHRs).Methods We used a multistate network of community health centres to describe the extent to which country of birth is recorded in EHRs in Latinos,and to describe demographic features and cardiovascular risk profiles by country of *** compared geographical/demographic/clinical characteristics,from 2012 to 2020(9 years of data),of 914495 Latinos recorded as US-born,non-US-born and without a country of birth *** also described the state in which these data were *** Country of birth was collected for 127138 Latinos in 782 clinics in 22 *** with those with a country of birth recorded,Latinos without this record were more often uninsured and less often preferred *** covariate adjusted prevalence of heart disease and risk factors were similar between the three groups,when results were disaggregated to five specific Latin countries(Mexico,Guatemala,Dominican Republic,Cuba,El Salvador),significant variation was observed,especially in diabetes,hypertension and *** In a multistate network,thousands of non-US-born,US-born and patients without a country of birth recorded had differing demographic characteristics,but clinical variation was not observed until data was disaggregated into specific country of *** policies that enhance the safety of immigrant populations may enhance the collection of health equity related *** and effective health equity research using Latino country of birth information paired with longitudinal healthcare information found in EHRs might have significant potential for aiding clinical and public health practice,but it d

关键词： Latin rigorous sectional

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英特尔需要执行转型计划而不是被人收购

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商业周刊（中文版） 2024年第15期 14-16页

作者： dave Lee 逸思(译) 不详

有人说,如果硅谷有座拉什莫尔山,那么第一张被刻凿在石头上的脸应当是戈登·摩尔(Gordon Moore)。这位英特尔公司(Intel Corp.)联合创始人对集成电路上容纳半导体数量增长速度的著名论断,为美国在科技领域的领先地位奠定了基础。

关键词：增长速度集成电路第一张英特尔收购著名论断半导体

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Changes in Soil Physicochemical Properties under Selected Climate-Smart Agricultural Practices in Central African Republic

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Open Journal of Soil Science 2024年第1期14卷 97-114页

作者： Julie Léancy Gougodo De Mon-Zoni Arnauld dave Bangane Konzoba Jane Akoth Omenda Mohammad Zaman Ephrem Kosh-Komba Plant and Fungal Biodiversity Laboratory Faculty of Sciences University of Bangui Central African Republic Central African Institute for Agricultural Research (ICRA) Bangui Central African Republic Laboratoiry of Geoscience Faculty of Sciences University of Bangui Bangui Central African Republic Departement of Water & Agricultural Resources Management University of Embu Embu Kenya International Atomic Energy Agency (IAEA) Vienna Austria Laboratory of Biological and Agronomical Sciences for Development Faculty of Sciences University of Bangui Bangui Central African Republic

Soil nutrient depletion as a result of continuous cultivation with insufficient external nutrient replenishment is a major challenge in sub-Saharan Africa (SSA). A trial using the organic and mineral fertilizer was established in the cassava cropping system of the Pissa and Damara areas to address the declining soil fertility. The study aimed to evaluate the effect of cow manure and mineral fertilizer in combination or sole application on soil physico-chemical properties and macronutrients. The experimental trial adopted a randomized complete block design (RCBD) replicated four times. The treatments comprised of;T1 (Control), T2 (Peasant practice), T3 (sole NPK), and T4 (Cow manure + NPK). The data on soil physicochemical analysis was subjected to a one-way analysis of variance in SAS 9.4 and the mean was separated by Tukey’s HSD test at p < 0.005. The soil pH values ranged from 4.20 to 4.91;and 4.53 to 5.28 in Pissa and Damara respectively. According to the treatments, a low pH value is observed in T3 (4.13) in the Pissa. Combined use of cow manure and the mineral fertilizer resulted in higher Mg K and N in the Pissa region and higher soil pH in Damara. The use of sole NPK (T3) gave a higher soil carbon and CN ratio. In the Pissa region the CEC, Cu, Fe, and Zn were higher in the treatments with mineral fertilizer compared to the control. Conclusively, the use of mineral fertilizer and cow manure can be used with optimum rates to improve soil physico-chemical properties on a sustainable basis.

关键词： Cow Manure Physicochemical Nutrients Agroecology Nutrient Management

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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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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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租赁宇宙

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世界科学 2024年第6期 62-63页

作者：思羽戴夫·卡瓦诺

在玩模拟游戏的时候，常常会冒出一个想法：我们所处的宇宙会不会就是一个我们无法想象到的种族的玩具呢？下面这篇《租赁宇宙》的作者就将这个想法写成了小说。嘿，伙计们！欢迎来到租赁宇宙商店。这是为无尽人生准备的无尽娱乐。是第...

在玩模拟游戏的时候，常常会冒出一个想法：我们所处的宇宙会不会就是一个我们无法想象到的种族的玩具呢？下面这篇《租赁宇宙》的作者就将这个想法写成了小说。嘿，伙计们！欢迎来到租赁宇宙商店。这是为无尽人生准备的无尽娱乐。是第一次光顾吗？棒极了。等你准备结账离开时，我们会为你注册一个新账号，但是首先呢，我要先带领你们参观一下商店，解释租赁步骤，向你们展示可选择的宇宙类型，诸如此类。那么，我们目前的库存中共有超过8000个宇宙，还源源不断地有新发布的宇宙从各大宇宙创造工作室中问世。你们在店铺中见到的所有宇宙都仅供出租，不过我们偶尔会折价出售一些较老的宇宙，你们可以订阅我们的新闻简报，以便在我们销售宇宙时收到通知。

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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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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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