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

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

https://www.massey.ac.nz/~ychisti/Biodiesel.pdf

Biodiesel from microalgae.

Fast pyrolysis utilizes biomass to produce a product that is used both as an energy source and a feedstock for chemical production. Considerable efforts have been made to convert wood biomass to liquid fuels and chemicals since the oil crisis in mid-1970s. This review focuses on the recent developments in the wood pyrolysis and reports the characteristics of the resulting bio-oils, which are the main products of fast wood pyrolysis. Virtually any form of biomass can be considered for fast pyrolysis. Most work has been performed on wood, because of its consistency and comparability between tests. However, nearly 100 types of biomass have been tested, ranging from agricultural wastes such as straw, olive pits, and nut shells to energy crops such as miscanthus and sorghum. Forestry wastes such as bark and thinnings and other solid wastes, including sewage sludge and leather wastes, have also been studied. In this review, the main (although not exclusive) emphasis has been given to wood. The literature on woo...

Pyrolysis of Wood/Biomass for Bio-oil: A Critical Review

Sustainable economic and industrial growth requires safe, sustainable resources of energy. For the future re-arrangement of a sustainable economy to biological raw materials, completely new approaches in research and development, production, and economy are necessary. The ‘first-generation’ biofuels appear unsustainable because of the potential stress that their production places on food commodities. For organic chemicals and materials these needs to follow a biorefinery model under environmentally sustainable conditions. Where these operate at present, their product range is largely limited to simple materials (i.e. cellulose, ethanol, and biofuels). Second generation biorefineries need to build on the need for sustainable chemical products through modern and proven green chemical technologies such as bioprocessing including pyrolysis, Fisher Tropsch, and other catalytic processes in order to make more complex molecules and materials on which a future sustainable society will be based. This review focus on cost effective technologies and the processes to convert biomass into useful liquid biofuels and bioproducts, with particular focus on some biorefinery concepts based on different feedstocks aiming at the integral utilization of these feedstocks for the production of value added chemicals.

http://staff.cimap.res.in/PublicationFiles/Renew_Sustain_Energ_Rev_14_578.pdf

Production of first and second generation biofuels: A comprehensive review

Hydrothermal processing of waste pine wood into industrially useful products

Spent coffee grounds have been selected as a potential feedstock to synthesize activated carbon (AC) through physical activation. The activation parameters were optimized by employing the Box-Behnken design method. The impact of input activation parameters included the activation temperature (600-800 ℃), holding time (60-120 mins) and CO 2 flow rate (150-250 mL/min). Accordingly, at the optimum conditions obtained at 800 ℃, 90 min and 150 mL/min, the predicted response of specific surface area (1202.1 m 2 /g) was in good agreement with the actual response 1224 m 2 /g. Furthermore, deep eutectic solvent (DES) has been used to tailor the surface functionalities of the optimized AC (pristine). The change in textural characteristics, surface chemistry and morphology of the pristine and DES-AC samples were characterized by using complementary analytical techniques, including ultimate analysis, ash content, textural characteristics, XRD, CO 2 -TPD, TGA, XPS and SEM analyses. The studies highlighted change in physicochemical properties after the impregnation. For instance, the surface area of the DES-functionalized AC reduced to 1033 m 2 /g, but more basic functional moieties developed on the surface. The DES-AC has shown adequate CO 2 capture performance of 5.5 mmol/g compared to pristine AC (4.34 mmol/g) at 25 ℃ and 15 vol % of CO 2 (in N 2 ). Furthermore, DES functionalized AC has shown excellent selectivity in a dynamic mixture stream of CO 2 /N 2 and facile regeneration (92% retention) after multiple adsorption-desorption runs. Hence, preparing AC from SCG via physical activation and DES impregnation could be proposed as a promising valorization strategy to alleviate the CO 2 emission problem. • The potential of spent coffee grounds to synthesize activated carbon was investigated. • The preparation conditions were optimized using the Box Behnken Design method. • Deep eutectic solvent (DES) was used to functionalize the activated carbon. • The functionalized activated carbon displayed maximum CO 2 adsorption capacity of 5.5 mmol/g. • The DES functionalized activated carbon displayed thermal stability for industrial use. 

Preparation of activated carbon from spent coffee grounds and functionalization by deep eutectic solvent: Effect of textural properties and surface chemistry on CO2 capture performance

Conversion of Municipal Solid Waste to Biofuels

Cannabis indica stems were hydrolyzed with subcritical water at various temperatures, reaction times, and feed concentrations. The highest total yield of reducing sugars of 16.4 wt % was obtained at 190 °C in 37.5 min with a feed concentration of 3.5 wt %. Solid residues from the optimized process were treated with 0.5 M NaOH (pulping) and 0.5–3 % H2O2 (bleaching) to isolate cellulose fibers. The maximum yield of cellulose was 34.8 wt % with lowest lignin content of 0.5 wt %. With the removal of hemicellulose and lignin through the integrated hydrothermal processes, the crystallinity index and thermal stability of the cellulose fibers increased. 

Extraction of sugars and cellulose fibers from
 Cannabis
 stems by hydrolysis, pulping and bleaching

Modified Fischer−Tropsch (MFT) synthesis was performed at atmospheric pressure in a fixed-bed microreactor with a dual-bed configuration using Co−Ni−ZrO2 and sulfated-TiO2 solid acid catalysts. The sulfate loading in the sulfated-TiO2 catalyst was in the range 5−15 wt % whereas sulfated-TiO2 to Co−Ni−ZrO2 catalyst mass ratio was 1−3. The catalyst system was activated by reduction at temperatures ranging from 573 to 723 K for 16 h whereas sulfated-TiO2 catalyst was calcined at temperatures in the range 723−923 K for 4 h. MFT reactions were performed at weight hourly space velocities (WHSV) in the range 5−20 h-1 and reaction temperatures ranging from 513 to 533 K. Though these parameters did not have substantial effects on the hydrocarbon product composition, the optimum selectivities for C5+ hydrocarbons, i-C4 hydrocarbons, and C2−C4 olefins from syngas using Co−Ni−ZrO2 due to the presence of the modifier sulfated-TiO2 were increased from 26 to 31 wt %, 2 to 4 wt % and 34 to 44 wt %, respectively. However,...

Performance evaluation of Sulfated-TiO2 as a modifier to Co-Ni-ZrO2 catalyst in a dual-bed reactor for the selective production of C4 hydrocarbons from syngas

Ajay K. Dalai

Papers

Hydrothermal processing of waste pine wood into industrially useful products

Preparation of activated carbon from spent coffee grounds and functionalization by deep eutectic solvent: Effect of textural properties and surface chemistry on CO2 capture performance

Conversion of Municipal Solid Waste to Biofuels

Extraction of sugars and cellulose fibers from Cannabis stems by hydrolysis, pulping and bleaching

Performance evaluation of Sulfated-TiO2 as a modifier to Co-Ni-ZrO2 catalyst in a dual-bed reactor for the selective production of C4 hydrocarbons from syngas