Smart Manipulation of Gas Bubbles in Harsh Environments Via a Fluorinert-Infused Shape-Gradient Slippery Surface

Fundamental research and practical applications have examined the manipulation of gas bubbles on open surfaces in lowsurface-tension,high-pressure,and high-acidity,-alkalinity,or-salinity environments.However,to the best of our knowledge,effi cient and general approaches to achieve the smart manipulation of gas bubbles in these harsh environments are limited.Herein,a Fluorinert-infused shape-gradient slippery surface(FSSS)that could eff ectively regulate the behavior of gas bubbles in harsh environments was successfully fabricated.The unique capability of FSSS was mainly attributed to the properties of Fluorinert,which include chemical inertness and incompressibility.The shape-gradient morphology of FSSS could induce asymmetric driving forces to move gas bubbles directionally on open surfaces.Factors infl uencing gas bubble transport on FSSS,such as the apex angle of the slippery surface and the surface tension of the aqueous environment,were carefully investigated,and large apex angles were found to result in large initial transport velocities and short transport distances.Lowering the surface tension of the aqueous environment is unfavorable to bubble transport.Nevertheless,FSSS could transport gas bubbles in aqueous environments with surface tensions as low as 28.5±0.1 mN/m,which is lower than that of many organic solvents(e.g.,formamide,ethylene glycol,and dimethylformamide).In addition,FSSS could also realize the facile manipulation of gas bubbles in various aqueous environments,e.g.,high pressure(~6.8 atm),high acidity(1 mol/L H 2 SO 4),high alkalinity(1 mol/L NaOH),and high salinity(1 mol/L NaCl).The current fi ndings provide a source of knowledge and inspiration for studies on bubble-related interfacial phenomena and contribute to scientifi c and technological developments for controllable bubble manipulation in harsh environments.

Seismic Evaluation of Reinforced Concrete Frames in the Harsh Environment Using Pushover Analysis

The main objective of this paper is to evaluate the seismic response of buildings of typical reinforced concrete frames when concrete starts to deteriorate gradually and to make a comparison between the base shear and the displacement at different stages of earthquake loading. Typical 5, 15, 20 and 30-storey reinforced concrete frames have been designed for seismicity according to the recently adopted seismic code in Abu Dhabi, ACI 318-08/IBC 2009 code. A pushover analysis has been performed to these four buildings by using SAP 2000. Twenty-four models have been created (6 models for each building) by decreasing the concrete strength gradually from 4000 psi (281 kg/cm2) to 1500 psi (105 kg/cm2). This is to simulate the effect of harsh environment on the strength of concrete in existing buildings.

Eutectogel-based self-powered wearable sensor for health monitoring in harsh environments

Triboelectric nanogenerators(TENG)have emerged as a highly promising energy harvesting technology,attracting significant attention in recent years for their broad applications.Gel-based TENGs,with superior stretchability and sensitivity,have been widely reported as wearable sensors.However,the traditional hydrogel-based TENGs suffer from freezing at low temperatures and drying at high temperatures,resulting in malfunctions.In this study,we introduce an anti-freezing eutectogel,which uses a deep eutectic solvent(DES),to improve the stability and electrical conductivity of TENGs in harsh environmental conditions.The eutectogel-based TENG(E-TENG)produces an open-circuit voltage of 776 V,a short-circuit current of 1.54μA,and a maximum peak power of 1.1 mW.Moreover,the E-TENG exhibits exceptional mechanical properties with an elongation at a break of 476%under tension.Importantly,it maintains impressive performances across a wide temperature range from−18 to 60℃,with conductivities of 2.15 S/m at−10℃and 1.75 S/m at−18℃.Based on the excellent weight stability of the E-TENG sensor,motion sensing can be achieved in the air,and even underwater.Finally,the versatility of the E-TENG can serve as a wearable sensor,by integrating it with Bluetooth technology.The self-powered E-TENG can monitor various human motion signals in real-time and send the health signals directly to mobile phones.This research paves a new road for the applications of TENGs in harsh environments,offering wireless flexible sensors with real-time health signal monitoring capabilities.

Precision in harsh environments

Microsystems are increasingly being applied in harsh and/or inaccessible environments,but many markets expect the same level of functionality for long periods of time.Harsh environments cover areas that can be subjected to high temperature,(bio)-chemical and mechanical disturbances,electromagnetic noise,radiation,or high vacuum.In the field of actuators,the devices must maintain stringent accuracy specifications for displacement,force,and response times,among others.These new requirements present additional challenges in the compensation for or elimination of cross-sensitivities.Many state-of-the-art precision devices lose their precision and reliability when exposed to harsh environments.It is also important that advanced sensor and actuator systems maintain maximum autonomy such that the devices can operate independently with low maintenance.The next-generation microsystems will be deployed in remote and/or inaccessible and harsh environments that present many challenges to sensor design,materials,device functionality,and packaging.All of these aspects of integrated sensors and actuator microsystems require a multidisciplinary approach to overcome these challenges.The main areas of importance are in the fields of materials science,micro/nano-fabrication technology,device design,circuitry and systems,(first-level)packaging,and measurement strategy.This study examines the challenges presented by harsh environments and investigates the required approaches.Examples of successful devices are also given.

Fiber optic sensing technologies potentially applicable for hypersonic wind tunnel harsh environments

Advanced sensing techniques are in big demand for applications in hypersonic wind tunnel harsh environments,such as aero(thermo)dynamics measurements,thermal protection of aircraft structures,air-breathing propulsion,light-weighted and highstrength materials,etc.In comparison with traditional electromechanical or electronic sensors,the fiber optic sensors have relatively high potential to work in hypersonic wind tunnel,due to the capability of responding to a wide variety of parameters,high resolution,miniature size,high resistant to electromagnetic and radio frequency interferences,and multiplexing,and so on.This article has classified and summarized the research status and the representative achievement on the fiber optic sensing technologies,giving special attention to the summary of research status on the popular Fabry-Perot interferometric,fiber Bragg gratings and(quasi)distributed fiber optic sensors working in hypersonic wind tunnel environment,and discussed the current problems in special optical fiber sensing technologies.This article would be regarded as reference for the researchers in hypersonic wind tunnel experiment field.

A Track Initiation Method for the Underwater Target Tracking Environment

A novel efficient track initiation method is proposed for the harsh underwater target tracking environment(heavy clutter and large measurement errors): track splitting, evaluating, pruning and merging method(TSEPM). Track initiation demands that the method should determine the existence and initial state of a target quickly and correctly.Heavy clutter and large measurement errors certainly pose additional difficulties and challenges, which deteriorate and complicate the track initiation in the harsh underwater target tracking environment. There are three primary shortcomings for the current track initiation methods to initialize a target:(a) they cannot eliminate the turbulences of clutter effectively;(b) there may be a high false alarm probability and low detection probability of a track;(c) they cannot estimate the initial state for a new confirmed track correctly. Based on the multiple hypotheses tracking principle and modified logic-based track initiation method, in order to increase the detection probability of a track,track splitting creates a large number of tracks which include the true track originated from the target. And in order to decrease the false alarm probability, based on the evaluation mechanism, track pruning and track merging are proposed to reduce the false tracks. TSEPM method can deal with the track initiation problems derived from heavy clutter and large measurement errors, determine the target’s existence and estimate its initial state with the least squares method. What’s more, our method is fully automatic and does not require any kind manual input for initializing and tuning any parameter. Simulation results indicate that our new method improves significantly the performance of the track initiation in the harsh underwater target tracking environment.

恶劣环境下广播电视发射塔维护要点分析

广播电视发射塔是发射广播电视信号的重要组成部分,而广播电视发射塔大部分都是长期工作在环境较差的室外高空,极易受到雨雪、雷电、强风、冰冻、潮湿环境而影响正常工作,这也对发射塔的日常巡检维护和专业维护提出了更高要求。本文就长岛广播电视发射塔的专业维护进行简要阐述,以供相关人员参考。

环境犯罪的严厉执法:美国经验及其启示

美国环境刑事执法十分严厉,其基础包括环境刑事立法的保证、专门环境刑事执法机构的设置、环境刑事执法部门之间的合作、民众的普遍支持和追诉积极、量刑严厉。我国面对生态环境质量恶化的严峻情势,可以借鉴美国环境刑事执法的经验,环境刑法立法应突出对环境犯罪的威慑,借助司法解释限制法官量刑轻缓化倾向,设置专门的环境刑事执法部门,强化跨部门、区域性合作。

Heat Management System for Long-term Continuous Observation of Electronic Instrumentation in Deep Earth

Deep penetration into the Earth’s interior and direct monitoring of weak changes in physical fields and their cumulative processes and effects in the deep Earth can enhance the identification of deep Earth targets and deepen the degree of knowledge of the details of the deep Earth structure and deep processes(Moskvitch,2014),which is important for promoting the development of Earth system science.

火炮发射恶劣环境下存储测试仪的可靠性设计

存储测试仪是火炮发射过程中动态参数测试的首选装置,在使用中往往面临恶劣的测试环境,其可靠性是影响测试结果的关键因素之一。通过分析恶劣环境因子对存储测试仪输出的影响,分别从电路模块、电池和防护壳体几个主要部件进行失效模式分析,并针对性地提出了提高其可靠性的有效方法,详细说明了真空灌封的工艺流程,对存储测试仪的可靠性设计有一定的价值。

漠河低温工作极值及其统计方法探讨

为提高漠河试验站低温工作极值统计的准确性,推进低温工作极值在装备低温环境适应性评估中的应用。以最低温度、平均温度、小于–35℃的天数为基准条件,分别统计了漠河不同年份的低温工作极值,研究了基准条件、统计年份、数据缺失情况对严酷月确定和工作极值的影响。基准条件、统计年份、数据缺失都会影响严酷月的确定和低温工作极值的统计,统计年份的影响比基准条件大,数据缺失影响的严重性需要看数据缺失的多少和时间段。工作极值结果至少包括数据年限、基准条件、严酷月、时间风险率、与时间风险率对应的工作极值等内容。1991—2005年,时间风险率为1%、5%、10%、20%、30%的最低温度工作极值分别为:–44.0、–40.7、–38.1、–35.6、–33.6℃。

浅析核电厂数字化安全系统仪控设备鉴定的措施和方法

目前在役核电厂中,仪控系统广泛采用模拟设备,但是随着科学技术的发展,数字化安全系统仪控设备逐步应用到新建核电厂,设备鉴定的要求也发生了变化。为适应这一新技术的应用,一些机构进行了相关的技术研究。文章简单概括了这些研究结果,和现行的鉴定标准进行了比对和分析,并就核电厂数字化安全系统仪控设备环境鉴定的措施和方法提出了建议。

适用于严苛环境的储能变流器散热方案研究

大容量箱式储能变流器产品多为强迫风冷散热方式,为保证散热风量需要与外界进行大量空气交换。针对一些严苛环境地区,比如沿海高盐雾地区、沙尘较重地区等,空气质量较差,如果散热设计处理不当会存在一定风险,影响设备性能及寿命。为了提升产品环境适应性,保证产品散热性能,分别对空调散热变流舱方案、风机冷却升压舱方案进行了研究,为严苛环境下大容量风冷散热产品应用提供了解决方案。

应用型大学本科生科技创新与研发典型案例分析--以泰山学院为例

文章基于应用型大学的学生科技创新与研发典型案例,结合本团队实践探索培养大学生科技创新能力的新途径。文章提出一种小型的采用柔性有机太阳能电池板发电的智能捕捉与自我保护装置,该太阳能电池板区别于传统的硅太阳能电池板的主要特性是具有成本低、可折叠、可剪裁以及良好的透光性;同时通过外界环境捕捉器设计和优化恶劣环境保护系统和太阳光照角捕捉系统,为进一步开发和应用大规模室外有机电池板提供了支持和借鉴,该产品的研发对于培养应用型大学的学生科技创新能力是一个有益的探索和途径。

针式打印机抗恶劣环境适应性加固技术

文章主要对针式打印机为适应军用计算机系统恶劣环境条件适应性提出了针对性解决方案,采用这些加固技术措施可以提高针式打印机的环境适应性。

Hydrophobic aerogel-modified hemostatic gauze with thermal management performance

Current hemostatic agents or dressings are not efficient under extremely hot and cold environments due to deterioration of active ingredients,water evaporation and ice crystal growth.To address these challenges,we engineered a biocompatible hemostatic system with thermoregulatory properties for harsh conditions by combining the asymmetric wetting nano-silica aerogel coated-gauze(AWNSA@G)with a layer-by-layer(LBL)structure.Our AWNSA@G was a dressing with a tunable wettability prepared by spraying the hydrophobic nano-silica aerogel onto the gauze from different distances.The hemostatic time and blood loss of the AWNSA@G were 5.1 and 6.9 times lower than normal gauze in rat’s injured femoral artery model.Moreover,the modified gauze was torn off after hemostasis without rebleeding,approximately 23.8 times of peak peeling force lower than normal gauze.For the LBL structure,consisting of the nano-silica aerogel layer and a n-octadecane phase change material layer,in both hot(70℃)and cold(-27℃)environments,exhibited dual-functional thermal management and maintained a stable internal temperature.We further verified our composite presented superior blood coagulation effect in extreme environments due to the LBL structure,the pro-coagulant properties of nano-silica aerogel and unidirectional fluid pumping of AWNSA@G.Our work,therefore,shows great hemostasis potential under normal and extreme temperature environments.

Electromagnetic wave absorbing ceramics composites made of polymer-derived SiC with BN@CNTs pyrolyzed higher than 1200℃

Polymer-derived ceramics(PDCs)pyrolyzed at high temperatures are promising electromagnetic wave(EMW)absorption materials for aerodynamically heated parts of aircraft under harsh environments.Nev-ertheless,high-temperature pyrolysis results in a significant increase of electrical and dielectric proper-ties of the ceramics,causing extensive reflection of EMW.To address this challenge,boron nitride-coated carbon nanotubes(BN@CNTs)were fabricated and introduced into polymer-derived SiC(PDC-SiC)by py-rolyzing its precursor higher than 1200℃to form SiC-BN@CNT ceramic composites.The fabricated com-posites with 3 wt.%BN@CNTs pyrolyzed at 1200℃have an effective absorption bandwidth(EAB)of 4.2 GHz(8.2-12.4 GHz)at a thickness of 3.4 mm and the minimum reflection loss(RL min)of-57.20 dB.The ultra-broad EAB of 12.62 GHz(5.38-18 GHz)is obtained by simulation through periodic structure design-ing.The RL of the metamaterials was also measured using an arch testing method at a frequency range of 2-18 GHz and an EAB of 11.52 GHz(6.48-18 GHz)is obtained.The excellent absorption is attributed to the BN layer that limits the electrical conduction of the ceramic composites while retaining the high loss of CNTs.The introduction of BN@CNTs causes the refinement of SiC grains,which provides plenty of interfaces and enhances the interface polarization loss.This work successfully solves the problem that PDCs pyrolyzed at elevated temperatures cannot be used as EMW absorption materials by applying BN coating on CNTs served as absorbers for PDC-SiC.The results of this work greatly broaden the application scope of the PDC systems for EMW absorption.

Polymer-derived SiBCN ceramic pressure sensor with excellent sensing performance

Pressure measurement with excellent stability and long time durability is highly desired,especially at high temperature and harsh environments.A polymer-derived silicoboron carbonitride(SiBCN)ceramic pressure sensor with excellent stability,accuracy,and repeatability is designed based on the giant piezoresistivity of SiBCN ceramics.The SiBCN ceramic sensor was packaged in a stainless steel case and tested using half Wheatstone bridge with the uniaxial pressure up to 10 MPa.The SiBCN ceramic showed a remarkable piezoresistive effect with the gauge factor(K)as high as 5500.The output voltage of packed SiBCN ceramic sensor changes monotonically and smoothly versus external pressure.The as received SiBCN pressure sensor possesses features of short response time,excellent repeatability,stability,sensitivity,and accuracy.Taking the excellent high temperature thermo-mechanical properties of polymer-derived SiBCN ceramics(e.g.,high temperature stability,oxidation/corrosion resistance)into account,SiBCN ceramic sensor has significant potential for pressure measurement at high temperature and harsh environments.

Traits uncover quasi-neutral community assembly in a coastal heath vegetation

Aims Trait-based approaches are increasingly being used in ecology due to their potential to explain and predict community structure and dynamic regardless of species identities.Here,we asked whether coastal heath vegetation established in stressful habitats could be assembled by quasi-neutral mechanisms based on functional trait distribution.Communities are organized through quasi-neutral dynamics if abiotic gradients and/or species interactions impose sorting on functional traits and species performances,but not on species phylogenetic relatedness and occurrence.Methods The study was conducted in a coastal area containing tall dunes near the sea,and relatively flat areas punctuated by short palaeodunes further inland,Northeastern South America.We evaluated 10 traits of the 21 most abundant species,as well as eight abiotic variables in 70 plots(25 m^(2))established in dune tops,valleys,flat and steep microenvironments.The effect of environmental filter was tested by linear mixed models(LMM)between each community-weighted mean(CWM)trait and the abiotic variables,and by two indices of environmental filtering based on intra-and interspecific-trait vari-ability relative to null models.To evaluate the effect of species inter-actions,we used an index of niche overlap relative to null models,and LMMs between this index and the species richness of plots.Important Findings The environmental filtering index did not deviate from null expect-ations for any trait.Models that included individual variability per-formed similarly to models that used species mean traits.However,the explicit consideration of environmental gradients by CWM ana-lyses revealed functional patterns that would remain undetected if trait distribution was analyzed only.In addition,intraspecific vari-ation in the stem length was an important driver of species diversity as suggested by the relationship between species richness and the niche overlap index.Based on the occurrence and phylogenetic re-latedness of species,previous work in the same system found neu-tral community assembly.We concluded that to ignore functional traits may lead to underestimations of niche-based processes,and that analyses of species occurrence and phylogenetic relatedness should be complemented with functional traits to reinforce our in-terpretation of processes underpinning community assembly.In this regard,the study heath vegetation is influenced by quasi-neutral effects on functional trait distribution.

恶劣环境条件下海外天然气管道站场事故演化知识图谱建模及预警方法

近年来恶劣环境条件(雷电、风、雨)频发,给长输油气管道尤其是海外油气管道的长期安全运行带来了重大威胁。海外油气管道的运行与应急救援面临着恶劣环境条件下的管道风险事故数据不足、跨国协同较为困难等问题。为解决当前管道事故预警模型过于依赖现场运行数据或事故相关数据的情况,该文利用恶劣环境条件下的天然气管道站场有限的事故文本数据,提出了一种基于知识图谱的站场事故演化预警模型。该模型采用双向长短期记忆网络-条件随机场算法(Bi-LSTM-CRF)对站场事故文本进行因果关系抽取,并加入了文本特征以增强抽取效果,然后利用Neo4j图数据库根据因果关系抽取的结果,建立了恶劣环境条件下海外天然气管道站场事故演化知识图谱。结果表明:相较于传统长输管道站场事故预警方法,该文所提出的基于知识图谱的站场事故预警模型不仅能够实现站场事故的预警,还能够实现对事故的路径预测以及事故应急决策推荐。这证明了该预警模型不仅可用性好,还能够有效地帮助海外天然气管道站场安全管理人员进行准确的风险控制与事故预防。