The Impact of Solid Waste Generation, Storage and Separation Practices among Households on the Environment in Freetown

As urbanization and population growth continue to increase in Freetown, due to changes in economic, social, environmental, political, and demographic factors, the municipal solid waste (MSW) generation also continues to increase, making its management difficult for the municipal authority. Efficient separation and storage of solid waste at the source of generation can boost resource and energy recovery from MSW. This study examines the municipal solid waste management (MSWM) process, focusing on generation, storage and separation practices among households and their impact on the environment in Freetown. It emphasizes the inclusion of MSWM programs in primary schools to raise public awareness, the implementation of effective waste management practices, and the enforcement of related policies to enhance the MSWM sector, contributing to sustainable MSWM in Freetown. By utilizing both qualitative and quantitative methods, 393 structured questionnaires were administered across three selected sections to collect data on household solid waste storage and separation practices. The analysis employed descriptive statistics, using Origin-Pro9 and MS Excel. The findings show that with a population of 1.53 million people in Freetown, the per capita solid waste generation is 0.58 kg per day. The findings also show that 97% of the households have storage facilities as a result of the increase in awareness and education about the proper storage of solid waste. However, 96% of respondents do not practice separation of solid waste at the source of generation, which has become a concern among researchers in Sierra Leone. Additionally, 88% of respondents are unaware of ISWM principles, with only 12% aware, most of whom have received some education on proper solid waste management. The study recommends improving MSWM in Freetown to protect public health and the environment.

Applications of metal–organic frameworks for green energy and environment: New advances in adsorptive gas separation, storage and removal

The separation of gas molecules with similar physicochemical properties is of high importance but practically entails a substantial energy penalty in chemical industry. Meanwhile, clean energy gases such as H_2 and CH_4 are considered as promising candidates for the replacement of traditional fossil fuels. However, the technologies for the storage of these gases are still immature. In addition, the release of anthropogenic toxic gases into the atmosphere is a worldwide threat of growing concern. Both in academia and industry, considerable research efforts have been devoted to developing advanced porous materials for the effective and energy-efficient separation, storage, or capture of the related gases. In contrast to conventional inorganic porous materials such as zeolites and activated carbons, metal–organic frameworks(MOFs) are considered as a type of promising materials for gas separation and storage. In this contribution, we review the recent research advance of MOFs in some relevant applications, including CO_2 capture, O_2 purification, separation of light hydrocarbons, separation of noble gases, storage of gases(CH_4,H_2, and C_2 H_2) for energy, and removal of some gaseous air pollutants(NH_3, NO_2, and SO_2). Finally, an outlook regarding the challenges of the future research of MOFs in these directions is given.

Storage stability of SBS modified bitumen based on mixed-level orthogonal array design

The styrene-butadiene-styrene（SBS） modified bitumens with different contents of SBS modifiers are stored in different conditions to study the storage stability of SBS modified bitumen.Mixed-level orthogonal array design（OAD） is used and factors such as SBS modifier content,storage time,storage temperature and container size are chosen in a mixed-level OAD with an OA16（31×44） matrix.Parameters like the separation softening point difference（the separation difference of the ring and ball softening point of the top and bottom samples） and the average softening point（the arithmetic mean of the softening points of the top and bottom samples） are proposed to evaluate the separation and the ageing of modified bitumen during storage in this experiment,respectively.The results reveal that the separation and the ageing during storage exhibit a complicated variation for storage temperature and time.The separation softening point difference decreases with the storage temperature rising from 20 to 120 ℃ and increases with the temperature exceeding 120 ℃,and the average softening point drops with the storage time being prolonged.Different storage conditions have various effects on the storage stability of SBS modified bitumen.

Synthesis gas production using oxygen storage materials as oxygen carrier over circulating fluidized bed

A novel process for synthesis gas production over Circulating Fluidized Bed （CFB） using oxygen storage materials as oxygen carder was reported. First, oxygen in the air was chemically fixed and converted to lattice oxygen of oxygen storage materials over regenerator, and then methane was selectively oxidized to synthesis gas with lattice oxygen of oxygen storage materials over riser reactor. The results from simulation reaction of CFB by sequential redox reaction on a fixed bed reactor using lanthanum-based perovskite LaFeO3 and La0.8Sr0.2Fe0.9CO0.1O3 oxides prepared by sol-gel, suggested that the depleted oxygen species could be regenerated, and methane could be oxidized to synthesis gas by lattice oxygen with high selectivity. The partial oxidation of methane to synthesis gas over CFB using lattice oxygen of the oxygen storage materials instead of gaseous oxygen should be possibly applicable.

Water storage changes in North America retrieved from GRACE gravity and GPS data

As global warming continues,the monitoring of changes in terrestrial water storage becomes increasingly important since it plays a critical role in understanding global change and water resource management.In North America as elsewhere in the world,changes in water resources strongly impact agriculture and animal husbandry.From a combination of Gravity Recovery and Climate Experiment（GRACE） gravity and Global Positioning System（GPS） data,it is recently found that water storage from August,2002 to March,2011 recovered after the extreme Canadian Prairies drought between 1999 and 2005.In this paper,we use GRACE monthly gravity data of Release 5 to track the water storage change from August,2002 to June,2014.In Canadian Prairies and the Great Lakes areas,the total water storage is found to have increased during the last decade by a rate of 73.8 ± 14.5 Gt/a,which is larger than that found in the previous study due to the longer time span of GRACE observations used and the reduction of the leakage error.We also find a long term decrease of water storage at a rate of-12.0 ± 4.2 Gt/a in Ungava Peninsula,possibly due to permafrost degradation and less snow accumulation during the winter in the region.In addition,the effect of total mass gain in the surveyed area,on present-day sea level,amounts to-0.18 mm/a,and thus should be taken into account in studies of global sea level change.

Rapid hydrate formation and efficient gas separation based on aqueous solid carrier

The long hydrate induction time and limited gas-liquid contact area leads to slow hydrate formation rate and low water-hydrate conversion rate.Porous media are often used to promote hydrate formation because of their large specific surface area.Consequently,we used 3A molecular sieve as a water-carrying solid in this work,and investigated the dynamic renewal of the gas-liquid interface and its effect on hydrate formation.The formation kinetics of ethane hydrate was first measured in an aqueous molecular sieve system.Then the separation of(H_(2)+CH_(4)+C_(2)H_(6)+C_(3)H_(8))gas mixture was conducted via hydrate formation.The results show that the formation rate and gas storage capacity of ethane hydrate can be greatly improved by using aqueous molecular sieve.Compared with a pure water system under the same temperature and pressure,aqueous molecular sieve has obvious advantages in separation effect and energy consumption for separating gas mixtures.

Rational design on separators and liquid electrolytes for safer lithium-ion batteries

As the energy density of lithium-ion batteries (LIBs) continues to increase,their safety has become a great concern for further practical large-scale applications.One of the ultimate solution of the safety issue is to develop intrinsically safe battery components,where the battery separators and liquid electrolytes are critical for the battery thermal runaway process.In this review,we summarize recent progress in the rational materials design on battery separators and liquid electrolyte towards the goal of improving the safety of LIBs.Also,some strategies for further improving safety of LIBs are also briefly outlooked.

Safer Lithium-Ion Batteries from the Separator Aspect:Development and Future Perspectives

With the rapid development of lithium-ion batteries(LIBs),safety problems are the great obstacles that restrict large-scale applications of LIBs,especially for the high-energy-density electric vehicle industry.Developing component materials(e.g.,cathode,anode,electrolyte,and separator)with high thermal stability and intrinsic safety is the ultimate solution to improve the safety of LIBs.Separators are crucial components that do not directly participate in electrochemical reactions during charging/discharging processes,but play a vital role in determining the electrochemical performance and safety of LIBs.In this review,the recent advances on traditional separators modified with ceramic materials and multifunctional separators ranging from the prevention of the thermal runaway to the flame retardant are summarized.The component–structure–performance relationship of separators and their effect on the comprehensive performance of LIBs are discussed in detail.Furthermore,the research challenges and future directions toward the advancement in separators for high-safety LIBs are also proposed.

Separator Material Chosen for MH/Ni Battery

The properties of MH/Ni batteries using different separator were studied.And then an idea for choosing separator for high-power MH/Ni battery was provided.Using the separator with grafting treatment, the storage characteristic, charge retention characteristic and anti-soft-short characteristic of high-power MH/Ni battery are improved.Wetlaid and spunfibre material meet different properties requirement of battery.

Separation of Formate Ion from a Catalytic Mixture after a Hydrogenation Process of Bicarbonate Ion and Generation of Formic Acid—The Last Stage of the Formic Acid Cycle

Formic acid is recognized as a promising hydrogen carrier. It readily decomposes to release hydrogen (and carbon dioxide) in the presence of apposite catalysts. The main deficiency of this practice is that the reverse reaction, the hydrogenation of carbon dioxide to formic acid is an uphill reaction necessitating extreme conditions. Carbon dioxide should be converted to bicarbonate salts since their hydrogenation is reasonable for storing hydrogen. The related approach has a drawback as formate salts are produced. The latter has lower weight percentage of hydrogen and they must be converted to formic acid. The goals of our research were to separate formate salt from the reaction mixture and to convert it to formic acid. In this paper, we present a process that combines the advantages of both methodologies—formic acid is the carrier, but the hydrogen is charged to a bicarbonate ion. This stage completes the formic acid cycle (FAC), which could operate as a continuous process for the production and storage of hydrogen. Additional research, including proper rescaling and optimization, should be carried out in order to assess the potential of such a process as a basis for replacing the present day combustion of fossil fuels with hydrogen usage in fuel cells.

储氚组件中氚依次渗透到相邻腔体的规律研究

考虑氚的时时和处处衰变,建立三腔体两隔片气路组件中隔片材料内部氚浓度控制方程,求解得到了渗透过隔片的瞬态氚量、中间腔体和右侧腔体中瞬态氚量和氚压力的高精度解析解.通过解析理论计算,认识了中间腔体和尾端腔体中瞬态氚压力随时间、储存温度和隔片厚度的变化规律,揭示出两个腔体中氚压力都具有最大单峰特性,且压力峰值出现时间几乎与隔片厚度无关等特性.研究结果为相关储氚装备的工程研制和使用提供了理论依据.

用于信息存储与防伪的动态荧光防冻水凝胶

目的 为了提高水凝胶在恶劣环境下的适应能力,探究在信息存储与防伪中的应用前景,本次研究制备一种荧光聚合物水凝胶,提高水凝胶的机械稳定性、保湿性、多环境稳定特性,以及实现将代码信息隐藏在水凝胶内部的测试。方法 在70℃下将羧甲基纤维素钠(CMC)溶于水/二甲基亚砜(DMSO)体系,并在此基础上添加丙烯酸、丙烯酰胺、丙烯酸-2甲氧基乙酯等,用荧光溶液书写特定图案,最后将混合溶液进行紫外光固化,宏观上利用万能试验拉伸机、差式扫描量热仪对其进行力学与防冻性能表征;在微观上使用傅里叶红外光谱、扫描电子显微镜对其内部物质与形貌特征进行描述。结果 结果表明,水/DMSO体系可以提高低温下凝胶的力学性能;其次,制备得到的透明水凝胶在水浸泡下会出现溶胀现象,然后在DMSO溶液中恢复透明,利用这一现象可以实现荧光信息的隐藏与加密。结论 利用水凝胶在不良溶剂中的微相分离和有机溶剂中的溶胀现象,将荧光图案隐藏在其中,溶胀时紫外光下不显示信息,待恢复透明时信息可见,使其在信息加密领域具有广阔的应用前景。

Porous framework materials for energy&environment relevant applications:A systematic review

Carbon peaking and carbon neutralization trigger a technical revolution in energy&environment related fields.Development of new technologies for green energy production and storage,industrial energy saving and efficiency reinforcement,carbon capture,and pollutant gas treatment is in highly imperious demand.The emerging porous framework materials such as metal–organic frameworks(MOFs),covalent organic frameworks(COFs)and hydrogen-bonded organic frameworks(HOFs),owing to the permanent porosity,tremendous specific surface area,designable structure and customizable functionality,have shown great potential in major energy-consuming industrial processes,including sustainable energy gas catalytic conversion,energy-efficient industrial gas separation and storage.Herein,this manuscript presents a systematic review of porous framework materials for global and comprehensive energy&environment related applications,from a macroscopic and application perspective.

膨润土基功能材料在电化学储能中的研究进展

膨润土是一种储量丰富、廉价易得的天然黏土矿物,其主要矿物成分为蒙脱石(MMT)。MMT因独特的二维层状纳米结构、丰富的孔隙结构和高比表面积而具有良好的离子交换性能、吸附性能和离子传输性能,而且热稳定性、化学稳定性和机械稳定性优异。近年来,MMT因上述特性,特别是其固有的金属离子(Li^(+)、Na^(+)、Zn^(2+)等)传输特性,引起了电化学储能领域研究人员的关注并被广泛用于电化学储能装置的关键部件(电极、聚合物电解质和隔膜),展现出了良好的应用前景。本文首先概述了膨润土的结构及理化特性,然后详细综述了膨润土基功能材料在电化学储能装置(主要包括金属负极、锂硫电池正极、固态/凝胶聚合物电解质、聚合物隔膜)中的应用研究进展,在此基础上重点阐述了膨润土基功能材料在电化学储能过程中促进离子传输的作用机理。最后总结了当前膨润土基功能材料在电化学储能装置领域所面临的问题和挑战,并对未来的研究方向进行了展望,以期为今后设计开发膨润土基电化学储能功能材料提供有益指导。

指控中心任务软件集中管控系统研究与关键技术

随着武器航天试验任务的增多,指控中心对任务软件快速部署、多任务并行的需求愈发迫切。设计了基于B/S架构的指控中心任务软件集中管控系统,实现了任务软件配置与监控的一体化管理;通过基于DBus与Kafka结合的数据传输机制,打通了任务软件与系统前后端数据高效交互链路;最后,重点分析了任务软件自动化部署技术、多任务并行技术、高速数据分级处理技术以及任务数据高效存储技术。

储能式低温空分系统热力学与经济性分析

低温空气分离设备是大型化工系统的高耗能环节,若与液态空气储能技术相结合,可有效平衡电网峰谷负荷,显著提高系统的经济效益。提出了一种储能式低温空分系统(ASU-ESG),利用谷电制取液态空气并储存,在峰电期内液态空气膨胀发电并参与低温精馏。此方案可有效降低系统在用电峰时的压缩负荷和电力成本,改善空分装置的负荷调节能力。研究结果表明,空气处理量为60000 m^(3)/h的ASU-ESG系统的日均制氧压缩功比功耗为0.378 kW·h/m^(3),储能和释能过程氧提取率分别为89.46%和93.71%。相比常规ASU系统,该系统的谷时压缩负荷提高了28%,峰时压缩负荷降低了20%,可节约年度用电成本5.72%~6.88%,动态回收期仅为3.3~4.3年,全生命周期净现值可达(19714.6~28074.7)万元。本系统可平衡电网峰谷波动,并利用电价差显著提高系统的经济效益。

储能的低温空气分离系统热力学与经济性分析

为探索低温空气分离系统(ASU)进行电力需求错峰运行的可行性,将传统空气分离技术与液态空气储能技术(LAES)结合,在谷电期先将富余空气压缩、液化、储存,在峰电期将液态空气作为精馏原料补充到精馏塔,以提高谷时压缩用电负荷、降低峰时压缩用电负荷。与传统空气分离系统相比,氧气产品的标准状态体积流量为10165m^(3)/h的低温空气分离储能系统(ASU-LAES)可将压缩能耗的20%由电网高峰时段转移到低谷时段,年度用电成本可减少1.3%~6.8%。ASU-LAES系统的制氧单位压缩能耗为0.349kW·h/m^(3),设备投资成本为4034.8万元,动态回收期为4.6~5.2a。ASU-LAES方案可缓解电网高峰负荷用电压力,充分利用峰谷分时电价政策优势,可创造良好的经济效益。

芒硝基相变储能材料的研究进展

芒硝(Na_(2)SO_(4)·10H_(2)O)作为一种原料易得、储能密度大的无机水合盐类相变储能材料(Phase Change Materials,PCMs),拥有相变温度适中、储能高等优点,然而,过冷度大、相分层严重、易泄露和导热率低等问题限制了芒硝基PCMs的大规模应用。通过总结关于过冷和相分离问题的改性方法,归纳比较了各类封装的原理及效果,并概述了通过导热强化来提高芒硝基PCMs储放热效率的研究进展。最后,对该材料的实际应用现状进行阐述,并展望了其发展方向,为开发高稳定性、高效封装、高导热率芒硝基PCMs提供参考依据。

不同有效应力下泥岩盖层二氧化碳突破压力演化特征的试验研究

针对不同有效应力下泥岩盖层二氧化碳(CO_(2))突破压力演化机制不清的问题,以中国渤海湾盆地粉砂质泥岩盖层为研究对象,开展了不同有效应力下突破压力和渗透率试验,研究了泥岩盖层CO_(2)突破压力演化过程,讨论了孔隙水膜对突破压力的影响机制。研究结果表明:CO_(2)注入时,盖层有效应力由27 MPa减小至7 MPa,盖层渗透率由从1.46×10^(-6)μm^(2)增加至1.81×10^(-6)μm^(2)。当有效应力为5.2 MPa时,盖层突破压力的最小值为3 MPa,其值高于盖层最小封闭界限值2 MPa,表明盖层具有CO_(2)有效封闭能力。孔隙水膜的分离压力和分布特征是影响突破压力的主要因素,CO_(2)运移阻力随水膜分离压力增加而增大,导致CO_(2)突破压力大。渤海湾盆地泥岩小孔径范围为0.1~2.5 nm,对应的水膜分离压力为5.2~50 MPa,水膜对CO_(2)运移的束缚能力较强。

某排水泵站全地下式初雨调蓄池设计

随着我国经济社会的不断发展,城市面源污染负荷正在逐年提高,对区域河道、湖泊等水环境质量造成了严重威胁。在排水系统末端设置初雨调蓄池,是控制径流污染、改善区域水环境的重要工程性措施之一。文章结合上海市位于商务区的某已建排水泵站处新建全地下初雨调蓄池的设计实例,针对全地下式初雨调蓄池的建设形式、运行模式、主要工艺类型选择等方面的主要问题,在占地面积、经济投资、管养维护等方面进行了研究和论证分析,并介绍了该初雨调蓄池主要工艺参数的优化设计方案,可为同类型全地下式排水泵站初雨调蓄池的设计提供一定思路参考。