The relevance of James Lovelock’s research and philosophy to environmental science and academia

James E. Lovelock, famed for his Gaia hypothesis, which views the Earth as a living integrated and interconnected self-regulating system whose equilibrium comes about from complex energy-based interactions and feedback loops, ultimately sustaining life, passed away at the end of July, 2022 at the age of 103. Not only are the adaptive mechanisms of Gaia central to the conversation of environmental homeostasis, they lie at the heart of climate change and global warming. Lovelock is also remembered as the co-inventor of the electron capture detector that eventually allowed for the sensitive detection of chlorofluorocarbons and pesticides. Finally, Lovelock’s free-spirited nature and research independence allow academia to rethink current research’s modus operandi.     

Photo-degradation organic dyes by Sb-based organic-inorganic hybrid ferroelectrics

The organic-inorganic hybrid halide compounds have emerged as one of the most promising photoelectric material for their superior optoelectronic properties and hold great prospects for renewable energy substitutes and environmental protection as photocatalysis. Here, we report the optical properties of the Sb-based organic-inorganic hybrid ferroelectric materials: pyridine-4-aminium tetrachloroantimonate ((C₅H₇N₂)SbCl₄, sample 1), piperidin-1-aminium tetrachloroantimonate ((C₅H₁₃N₂)SbCl₄, sample 2) and tris(trimethylammonium) nonachlorodiantimonate (((CH₃)₃NH)₃Sb₂Cl₉, sample 3), which are a kind of exploited efficient photocatalysts. Samples 2 and 3 exhibit distinct photoelectric respond, which are mainly ascribed to their minor narrow band-gap compared with sample 1. For the ferroelectrics, the intrinsic of spontaneous polarization of sample 3 at room temperature is favourable for the separation of photogenerated electrons and holes within the photorespond process. Moreover, sample 3 shows the highest efficiency of photo-decomposed Rhodamine B (90.2% within 80 min) and Methyl Orange (MO) (97.4% within 50 min), thanks to the photo-excited electrons and holes promoting the formation of oxidative radical species during the photo-redox progress. These findings prove that the development of a novel Sb-based organic-inorganic hybrid halide compounds with good stability in the degradation of organic dyes paves a way to designing new photocatalyst.     

提高前向散射型光电感烟探测器性能的算法

以国家科技部973项目中建立的火灾探测应用环境及火灾信息数据库为依据,对目前使用最为广泛的前向散射型光电感烟探测器固有特性的归纳和分析,通过数据挖掘,提出一种切实可行的算法处理技术和智能判断火灾方法,有效提高了现有前向散射型光电感烟探测器的火灾探测及其抗干扰能力。     

2011~2017年中国PM2.5多尺度时空分异特征分析

PM_2.5时空分异特征认知对大气污染联防联控意义重大,本文从空间多尺度的视角出发,利用空间模式分析方法与地理探测器,对2011~2017年中国大陆地区PM_2.5年均浓度时空分布格局及成因进行探究,从而揭示PM_2.5多尺度时空分异特征.结果表明：①2011~2017年PM_2.5年均浓度相对稳定,无明显趋势,国家与区域尺度PM_2.5变化特征基本一致,呈现"W"型变化,整体上看,污染程度由高到低依次为：中部、东部、西部与东北.②由空间模式分析结果可知,高值聚集区主要位于中国的东部、中部以及新疆的西南地区,低值聚集区则集中在青藏、云贵高原以及大兴安岭地区.③地理探测器分析结果证实：城市化因素中人口密度是国家与区域尺度上PM_2.5时空分异的主导因素,同时,产业、能耗与交通因素对PM_2.5分布格局存在不同程度影响.在区域尺度上,除了人口密度因素之外,工业用电量与公车总量对中部地区PM_2.5年均浓度影响较大,东部地区是工业烟粉尘排放量与道路面积,东北地区则为第二产业产值占比与城市绿地率,社会经济因素对西部地区的PM_2.5年均浓度影响不显著.     

Neutron activation analysis of ceramic tiles and its component and radon exhalation rate

IntroductionCeramic,consistofearthymaterialslikeclaykaolin ,limestoneandsandglass .Ceramicmaterialsarenonmetalic ,inorganiccompoundsprimaryoxides ,alsocarbides ,nitridesandsilicides .Twotypesofbondingmechanismsoccurinceramicmaterial ,ionicandcovalent.Theo…     

温度分层环境下火灾烟气羽流上升高度公式分析

对小尺度空间温度分层环境下柴油有焰火及棉绳阴燃火烟气运动进行了实验和数值模拟.结果表明,在分层环境下,烟气与环境空气温度差造成的浮力在某一高度消失并转为负值,致使烟气停止上升而向横向扩展.Morton积分公式低估了烟气羽流上升的最大高度,且在相同出口条件及分层环境下,柴油烟雾比棉绳烟雾下降趋势快,上升高度小,其原因在于积分公式中自相似卷吸及烟气为空气假设.引入烟气密度修正系数和自相似修正系数,对Morton公式进行了修正和讨论.     

受限空间烟气运动的盐水模拟原理

考虑烟气的浮力作用，合理地选取流场的特征参数，将烟气运动和盐水运动的基本方程无量纲化，分析两者之间的相似性，得到４个定性相似准则，其中Ｒｅ数是最主要的相似准则．并举例说明缩尺的盐水模拟实验可以满足相似准则。     

基于U-Net深度神经网络的早期火灾烟雾自动分割方法

在火灾事件监测中,为了减少数据处理量、加快探测速度,需要先分割出疑似烟雾区域。传统的烟雾分割算法大多需要设置阈值进行处理,算法的环境适应能力还需进一步提升。在研究中,使用U-Net结构的深度神经网络进行早期火灾烟雾的自动分割,通过半自动算法人工辅助分割出烟雾区域的图像样本,基于深度神经网络对分割烟雾区域进行学习,得到原始视频帧到分割结果的映射模型,并据此模型进行烟雾区域分割。在测试集上的分割实验结果表明该方法与传统方法相比,不需要设置阈值,自动化程度更高,分割速度极快,在疑似烟雾区域分割任务中性能较好。     

Radiometric and environmental impacts of mill tailings at experimental plant processing unit,Allouga, Egypt

Abstract

Uranium mining and ore processing are known to be harmful to the environment and human health if the waste generated is not managed properly. The aim of the present study is to determine the radiological indices in the mill tailings and review the possible attempts to utilize and minimize its hazardous effect. The activity concentrations of natural radionuclides, ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K have been measured by gamma spectrometry using HP-Ge detector. The average activity concentrations of ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K in the tailings wastes were 2071.8, 59.92, 6921.262, and 445. 57?Bq/kg respectively which are higher than the international average limit. The ranges of hazard indices such as Radium equivalent activity (Ra_eq), external hazard index (H_ex), internal hazard index (H_in), γ-radiation hazard index I_γ, Dose rate (nGy/h) and annual effective dose equivalent (AED), were estimated. Uraniumm isotopic ratios in the ore –material and mill tailing samples indicate migration out of radionuclides to the surrounding environment causing contamination and many dangerous diseases. Fairly, all investigated tailing waste samples do not satisfy the universal standards, the studied wastes relatively still have high uranium contents and need reprocessing.     

盾构铁路隧道坡度对火灾烟气蔓延的影响研究*

为研究坡度隧道内列车阻滞后的火灾烟气蔓延行为，利用火灾动力学模拟软件（FDS）建立盾构铁路隧道火灾模型和CRH6高速列车阻滞模型，隧道坡度分别为0%、1.0%、1.5%、2.0%、2.5%、3.0%、3.5%和4.0%，通过分析隧道内烟气、温度、能见度等特征参数的变化规律，研究坡度隧道内高温烟气的受力情况，探讨坡度变化对火灾烟气蔓延的作用机理。结果表明，坡度隧道内发生火灾，随着烟气的蔓延，隧道内形成沿坡度方向的烟囱效应力，使得烟气在火源两侧呈不对称分布。火源下游区域的高温烟气在火风压和烟囱效应的协同作用下蔓延速度比上游更快，下游烟气层分界中性面与隧道轴线平行，上游烟气层分界中性面呈现水平状态。有坡度的铁路隧道内发生火灾，建议向火源下游方向施加纵向机械通风，人员向火源的上游方向疏散逃生更安全。