There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Background Lignin, nature’s dominant aromatic polymer, is found in most terrestrial plants in the approximate range of 15 to 40% dry weight and provides structural integrity. Traditionally, most large-scale industrial processes that use plant polysaccharides have burned lignin to generate the power needed to productively transform biomass. The advent of biorefineries that convert cellulosic biomass into liquid transportation fuels will generate substantially more lignin than necessary to power the operation, and therefore efforts are underway to transform it to value-added products. Production of biofuels from cellulosic biomass requires separation of large quantities of the aromatic polymer lignin. In planta genetic engineering, enhanced extraction methods, and a deeper understanding of the structure of lignin are yielding promising opportunities for efficient conversion of this renewable resource to carbon fibers, polymers, commodity chemicals, and fuels. [Credit: Oak Ridge National Laboratory, U.S. Department of Energy] Advances Bioengineering to modify lignin structure and/or incorporate atypical components has shown promise toward facilitating recovery and chemical transformation of lignin under biorefinery conditions. The flexibility in lignin monomer composition has proven useful for enhancing extraction efficiency. Both the mining of genetic variants in native populations of bioenergy crops and direct genetic manipulation of biosynthesis pathways have produced lignin feedstocks with unique properties for coproduct development. Advances in analytical chemistry and computational modeling detail the structure of the modified lignin and direct bioengineering strategies for targeted properties. Refinement of biomass pretreatment technologies has further facilitated lignin recovery and enables catalytic modifications for desired chemical and physical properties. Outlook Potential high-value products from isolated lignin include low-cost carbon fiber, engineering plastics and thermoplastic elastomers, polymeric foams and membranes, and a variety of fuels and chemicals all currently sourced from petroleum. These lignin coproducts must be low cost and perform as well as petroleum-derived counterparts. Each product stream has its own distinct challenges. Development of renewable lignin-based polymers requires improved processing technologies coupled to tailored bioenergy crops incorporating lignin with the desired chemical and physical properties. For fuels and chemicals, multiple strategies have emerged for lignin depolymerization and upgrading, including thermochemical treatments and homogeneous and heterogeneous catalysis. The multifunctional nature of lignin has historically yielded multiple product streams, which require extensive separation and purification procedures, but engineering plant feedstocks for greater structural homogeneity and tailored functionality reduces this challenge.

https://lifelong.unt.edu/sites/default/files/EmeritusCollege/Spring2015/Handouts/Lignin%20co-products.pdf

Lignin valorization: improving lignin processing in the biorefinery.

China is the world's most populous country and a major emitter of greenhouse gases. Consequently, much research has focused on China's influence on climate change but somewhat less has been written about the impact of climate change on China. China experienced explosive economic growth in recent decades, but with only 7% of the world's arable land available to feed 22% of the world's population, China's economy may be vulnerable to climate change itself. We find, however, that notwithstanding the clear warming that has occurred in China in recent decades, current understanding does not allow a clear assessment of the impact of anthropogenic climate change on China's water resources and agriculture and therefore China's ability to feed its people. To reach a more definitive conclusion, future work must improve regional climate simulations-especially of precipitation-and develop a better understanding of the managed and unmanaged responses of crops to changes in climate, diseases, pests and atmospheric constituents.

http://re.indiaenvironmentportal.org.in/files/The%20impacts%20of%20climate%20change%20on%20water.pdf

The impacts of climate change on water resources and agriculture in China

Ultrasound assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review.

Oil production by oleaginous yeasts using the hydrolysate from pretreatment of wheat straw with dilute sulfuric acid

Nitrification kinetics of biofilm as affected by water quality factors

A laboratory study of producing docosahexaenoic acid from biodiesel-waste glycerol by microalgal fermentation

Catalytic co-pyrolysis of lignocellulosic biomass with polymers: a critical review

Kendall's test was used to analyze the hydro-climatic trends of the Yellow River over the last half century. The results show that: (1) the runoff of the basin has decreased even after allowing for human uses, (2) the watershed has become warmer with a more significant increase in minimum temperature than in mean and maximum temperatures, and (3) no significant change in precipitation trend was observed. The major reasons for these results include human activities, global warming, land use/land cover change, and others, such as accuracy of natural runoff estimation, precipitation characteristics, groundwater exploitation, water transfer, and snowmelt. Homogeneity analysis indicated that precipitation, temperature, maximum temperature, and minimum temperature were all heterogeneous and the trends varied from region to region and from month to month. If the Intergovernmental Panel on Climate Change (IPCC) projections of continued warming in the region during the 21st century are correct, the present results then suggest that the trend towards reduced runoff is likely to lead to exacerbated problems for agriculture, industry, urban communities, and the overall regional environment.

Shulin Chen

Papers

Oil production by oleaginous yeasts using the hydrolysate from pretreatment of wheat straw with dilute sulfuric acid

Nitrification kinetics of biofilm as affected by water quality factors

A laboratory study of producing docosahexaenoic acid from biodiesel-waste glycerol by microalgal fermentation

Catalytic co-pyrolysis of lignocellulosic biomass with polymers: a critical review

Hydro-climatic trends of the Yellow River basin for the last 50 years