A microfluidic approach for development of hybrid collagen-chitosan extracellular matrix-like membranes for on-chip cell cultures

To advance organ-on-a-chip development and other areas befitting from physiologically-relevant biomembranes,a microfluidic platform is presented for synthesis of biomembranes during gelation and investigation into their role as extracellular matrix supports.In this work,high-throughput studies of collagen,chitosan,and collagen-chitosan hybrid biomembranes were carried out to characterize and compare key properties as a function of the applied hydrodynamic conditions during gelation.Specifically,depending on the biopolymer material used,varying flow conditions during biomembrane gelation caused width,uniformity,and swelling ratio to be differently affected and controllable.Finally,cell viability studies of seeded fibroblasts were conducted,thus showing the potential for biological applications.     

Natural hydrogen emanations in Namibia: Field acquisition and vegetation indexes from multispectral satellite image analysis

Natural hydrogen exploration is now active in various places of the world. Onshore, correlation between natural H₂ generation and the presence of iron rich rocks especially from Archean and Neoproterozoic cratons have been observed. Emanations and accumulations of H₂ have already been confirmed in such geological settings in Australia, South Africa and Brazil. The geological similitude and the presence of numerous sub circular depressions that are a good proxy for hydrogen emanations suggest that hydrogen resources may also exist in Namibia. We present here the results of a data acquisition campaign which allowed us to confirm the presence of natural hydrogen in this country in the vicinity of Neoproterozoic Banded Iron Formation. The H₂ content in the soil, as in Brazil, is variable within the depressions in time and space and is particularly time sensitive across the day. Comparison of the H₂ signal versus time within these two regions shows a similar behavior of the soils with an increase of the H₂ flow at the middle of the day. In addition, these new data allow us to better constrain the morphological characteristics of such H₂-emiting depressions. By using satellite images and digital elevation model we propose a new proxy to differentiate potentially H₂-emiting features from other type of depressions such as Salt Pan. The Landsat multispectral images and their processing through NDVI and SAVI indexes, that highlight a ring of healthy vegetation around the sub circular area with scarce vegetation already observed appear able to discriminate between H₂ emitting structures and other soft depressions.     

Technical,economic, and environmental analyses of the modernization of a chamber furnace operating on natural gas or hydrogen

The paper presents a technical, economic and environmental analyses of a chamber furnace used to heat the charge before forging. The energy efficiency of the furnace before the modernization was 18%, after the modernization it was 31% (partial modernization due to large financial outlays). Other variants were also analysed: complete modernization, the variant of furnace modernization with 30% hydrogen content in the gas and the variant with 100% hydrogen as fuel. The analyses showed that with the current gas price (0.025 EUR/kWh) and the price of emission allowances (nearly 60 EUR/MgCO₂) and 100 cycles/year, the difference in Net Present Value (NPV) before base variant and partial modernization is around 900,000 EUR and before base variant and full modernization is 1,200,000 EUR. The introduction of the gas and 30% of hydrogen co-combustion option versus the base scenario option for 150 cycles per year results in a NPV difference of at least 2 million EUR. The option of 100% hydrogen as a fuel is the most advantageous from the point of view of reducing CO₂ emissions - it is largely influenced by the rising prices of CO₂ emission allowances.     

Economic competitiveness of compact steam methane reforming technology for on-site hydrogen supply: A Foshan case study

On-site hydrogen production through steam-methane reforming (SMR) from city gas or natural gas is believed to be a cost-effective way for hydrogen-based infrastructure due to high cost of hydrogen transportation. In recent years, there have been a lot of on-site hydrogen fueling stations under design or construction in China. This study introduces current developments and technology prospects of skid-mounted SMR hydrogen generator. Also, technical solutions and economic analysis are discussed based on China's first on-site hydrogen fueling station project in Foshan. The cost of hydrogen product from skid-mounted SMR hydrogen generator is about 23 CNY/kg with 3.24 CNY/Nm³ natural gas. If hydrogen price is 60 CNY/kg, IRR of on-site hydrogen fueling station project reaches to 10.8%. While natural gas price fall to 2.3 CNY/Nm³, the hydrogen cost can be reduced to 18 CNY/kg, and IRR can be raised to 13.1%. The conclusion is that skid-mounted SMR technology has matured and is developing towards more compact and intelligent design, and will be a promising way for hydrogen fueling infrastructures in near future.     

Eugenol,citral, and hexanal,alone or in combination with heat,affect viability,biofilm formation,and swarming on Shiga-toxin-producing Escherichia coli

Shiga-toxin-producing Escherichia coli strains are pathogenic for humans and cause mild to severe illnesses. In this study, the antimicrobial effect of citral, eugenol, and hexanal in combination with heat shock (HS) was evaluated in terms of the growth, biofilm formation, swarming, and expression of virulence genes of STEC serotypes (O157:H7, O103, O111, and O26). Eugenol was the most effective compound against the growth of E. coli strains (MBC = 0.58 to 0.73 mg/mL), followed by citral (MBC = 0.86 to 1.26 mg/mL) and hexanal (MBC = 2.24 to 2.52 mg/mL). Biofilm formation and swarming motility have great variability between STEC strains. Natural compounds—alone or combined with HS—inhibited biofilm formation; however, swarming motility was induced by most treatments. The expression of the studied genes during biofilm formation and swarming under natural antimicrobials was affected but not in a uniform pattern. These treatments could be used to control contamination of STEC and inhibit biofilm formation.     

Thermodynamic performance analysis and environmental impact assessment of an integrated system for hydrogen and ammonia generation

A novel multigeneration plant that's using natural gas for power, hydrogen, ammonia, and hot water generation, is planned and analyzed, in the current paper. The suggested combined plant integrated with four sub-systems, which are the Brayton cycle, reheat Rankine cycle, the high-temperature steam electrolyzer for hydrogen production, and ammonia synthesis processes. Also, thermodynamic analysis and environmental impact assessment are conducted for the designed plant and sub-systems. Moreover, the sustainability index analysis of this proposed study is conducted. The effects of some important indicators on the performance and on the environmental impact of the modeled system and sub-processes are also studied. According to analyses results, it is noted that the energetic and exergetic efficiencies of the suggested system are 51.83% and 70.27%, respectively, and also the total CO₂ emission rate is 11.4 kg/kWh for the integrated plant. Furthermore, the total irreversibility rate is computed as 40007.68 kW, and furthermore, the combustion chamber has a maximum irreversibility rate with 20,033 kW, among the proposed plant components.     

Recent progress on low-cost ceramic membrane for water and wastewater treatment

Great progress in the development of low-cost ceramic membranes from alternative materials have been achieved recently towards various application especially water and wastewater treatment. However, their significance has not been fully recognized and understood especially in term of their microstructural analysis such as formation of grain growth and microcracks. This review paper summarizes fabrication method, alternative materials, microstructure, wettability, mechanical properties and application of low-cost ceramic membrane. The fabrication method including slip casting, tape casting, extrusion, pressing method and phase inversion technique are described. Alternative materials used in low-cost ceramic membrane fabrication are discussed and categorized into clays, agricultural waste, industrial waste and animal bone waste. The mechanisms of morphology formation, microstructure and wettability properties are analysed. Modification strategies for the surface of low-cost ceramic membrane are discussed, and classified into modification for separation application, modification for photocatalytic application and modification for membrane distillation and membrane contactor system. Modification improves the membrane structure by changing the pore size, porosity and wettability properties of low-cost ceramic membranes. Mechanical properties of low-cost ceramic membranes are also discussed in detail towards several mechanism, like grain growth phenomenon and formation of microcracks which also considered as membrane defects. Grain growth phenomenon can be divided into normal and abnormal grain growth. Meanwhile, formation of microcracks could be occurred in single-phase polycrystalline ceramics that have anisotropic grains or biphasic polycrystalline grains. The application of low-cost ceramic membrane in seawater desalination, oily wastewater treatment, heavy metal adsorption, textile separation and photocatalytic application are reviewed. Finally, some possible opportunities and challenges for further development of low-cost ceramic membrane are pointed out.     

海洋非成岩天然气水合物原位快速制备实验及评价

我国的海洋天然气水合物（以下简称水合物）资源主要分布在沿海大陆架水深介于300～3 000 m的深水区，具有弱胶结、非成岩的特征，为了测试和研究该类型水合物必须原位、大量、快速制备样品，而目前常用的搅拌法、喷淋法、鼓泡法等制备技术却存在着生成速度慢、储气密度低等问题。为此，自主设计、研制了1 062 L非成岩水合物快速制备釜，针对我国南海非成岩水合物的物性特征，开展了搅拌法、鼓泡法、喷淋法单一制备方法及“三合一”法（上述3种方法相结合）水合物制备实验，测试了实验过程中温度、压力、电阻率及反应时间等数据，分析比较了几种不同制备方法的水合物生成情况与制备效率。实验结果表明：①搅拌法、鼓泡法、喷淋法制备水合物过程中，生成的水合物均缓慢增加并逐渐铺满整个液面；②搅拌法制备过程中可以观测到明显的诱导期，而喷淋法、鼓泡法及“三合一”法却无明显的诱导期；③单一制备方法及“三合一”法制备水合物过程中，电阻率均随反应时间的增加而增加，其变化趋势亦与水合物制备速率基本一致；④“三合一”法的制备周期明显短于单一制备方法（搅拌法、喷淋法、鼓泡法单一方法的制备时间分别约为“三合一”法的5.14倍、3.59倍、3.16倍）。结论认为，所研制的1 062 L水合物快速制备釜能够实现海洋非成岩水合物样品的原位、快速制备；较之于单一制备方法，“三合一”法大大提高了水合物的制备效率。     

Estonian urbanism 1935–1955: the Soviet-era implementation of pre-war ambitions

Estonian 1940s–1950s town planning practices show that Stalinist principles were in line with those of Estonian architects during the 1930s pre-war, independence period. However, between 1944 and 1955, within the context of the Soviet regime’s occupation, urban planning was faced with rigid ideological constraints. After the Second World War, Estonian architects were forced to abandon projects in historical city centres, which focused on maintaining local natural conditions and cultural heritage, as well as using local materials. Some existing town centres, such as in Tallinn, Narva, and Pärnu, were reconstructed after suffering damage in the war, as well as for ideological reasons. Yet, during this time period, most efforts were directed towards building new industrial towns in East Estonia that exemplified a Stalinist utopia; this also presented the Soviet regime with an opportunity to exploit local mineral resources.