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

Heterotrophic cultures of microalgae: Metabolism and potential products

Microalgae have recently attracted considerable interest worldwide, due to their extensive application potential in the renewable energy, biopharmaceutical, and nutraceutical industries. Microalgae are renewable, sustainable, and economical sources of biofuels, bioactive medicinal products, and food ingredients. Several microalgae species have been investigated for their potential as value-added products with remarkable pharmacological and biological qualities. As biofuels, they are a perfect substitute to liquid fossil fuels with respect to cost, renewability, and environmental concerns. Microalgae have a significant ability to convert atmospheric CO2 to useful products such as carbohydrates, lipids, and other bioactive metabolites. Although microalgae are feasible sources for bioenergy and biopharmaceuticals in general, some limitations and challenges remain, which must be overcome to upgrade the technology from pilot-phase to industrial level. The most challenging and crucial issues are enhancing microalgae growth rate and product synthesis, dewatering algae culture for biomass production, pretreating biomass, and optimizing the fermentation process in case of algal bioethanol production. The present review describes the advantages of microalgae for the production of biofuels and various bioactive compounds and discusses culturing parameters.

https://link.springer.com/content/pdf/10.1186/s12934-018-0879-x.pdf

The promising future of microalgae: current status, challenges, and optimization of a sustainable and renewable industry for biofuels, feed, and other products

Dual role of microalgae: Phycoremediation of domestic wastewater and biomass production for sustainable biofuels production

Process application of Subcritical Water Extraction (SWE) for algal bio-products and biofuels production.

The huge deficiency of electricity due to heavy reliance on imported fuels has become a significant impediment to socio-economic development in Pakistan. This scenario creates an increase in local fuel prices and limits potentials in the establishment of new industrial zones. The current gap between the demand and production of electricity in Pakistan is approximately 5000–8000 MW with a constant increase of 6–8 % per annum. Hence, more sustainable and renewable energy sources are required to overcome the existing problem. Pakistan is endowed with potential renewable energy resources such as wind, solar, hydro, and biomass. These resources have the capacity to be major contributors to future energy production matrix, climate change reduction efforts, and the sustainable energy development of the country. This article reviews the availability of alternative energy resources in Pakistan and associated potentials for full-scale development of sustainable energy systems. It also discusses exploitation strategies to increase the distribution of indigenous energy resources.

/pdf/renewable-energy-deployment-to-combat-energy-crisis-in-49tf5v3r6d.pdf

Renewable energy deployment to combat energy crisis in Pakistan

The gasification of green algae Chlorella vulgaris in air was investigated using both a thermogravimetric analyzer (TGA) and a bench scale horizontal axis quartz tube reactor (HQR). The full range of solid state kinetic models produced best fits with TGA results varied for the five subzones of conversion vs temperature, with the nucleation and nuclei growth “A2” followed by “A3” or contracting volume models producing close matches for T ≤ 367 °C, a zero-order model between 358 and 468 °C, and contracting surface models for T ≥ 458 °C; each model yielding their set of apparent activation energy (E 0.04 s–1) corresponding to rate constants in the range 0.001–0.005 s–1. The HQR was used to investigate the effects of microalgal biomass loading, temperature, and equivalence ratio (ER) on CnHm/CO/H2 gas yield and composition, carbon conversion efficiency (CCE), and lower heating value (LHV) of syngas under air gasification conditions. Increasing microalgal biomass...

https://pubs.acs.org/doi/pdf/10.1021/acs.energyfuels.6b03468

Parametric Characterization of Air Gasification of Chlorella vulgaris Biomass

Subcritical water extraction (SWE) technology has been used for the extraction of active compounds from different biomass materials with low process cost, mild operating conditions, short process times, and environmental sustainability. With the limited application of the technology to microalgal biomass, this work investigates parametrically the potential of subcritical water for high-yield extraction of biochemicals such as carbohydrates and proteins from microalgal biomass. The SWE process was optimized using central composite design (CCD) under varying process conditions of temperature (180–374°C), extraction time (1–20 min), biomass particulate size (38–250 μm), and microalgal biomass loading (5–40 wt.%). Chlorella vulgaris used in this study shows high volatile matter (83.5 wt.%) and carbon content (47.11 wt.%), giving advantage as a feedstock for biofuel production. The results showed maximum total carbohydrate content and protein yields of 14.2 g/100 g and 31.2 g/100 g, respectively, achieved under the process conditions of 277°C, 5% of microalgal biomass loading, and 5 min extraction time. Statistical analysis revealed that, of all the parameters investigated, temperature is the most critical during SWE of microalgal biomass for protein and carbohydrate production.

/pdf/subcritical-water-technology-for-enhanced-extraction-of-3y4lx2ycvb.pdf

Razif Harun

Papers

Process application of Subcritical Water Extraction (SWE) for algal bio-products and biofuels production.

Renewable energy deployment to combat energy crisis in Pakistan

Parametric Characterization of Air Gasification of Chlorella vulgaris Biomass

Subcritical Water Technology for Enhanced Extraction of Biochemical Compounds from Chlorella vulgaris

Role of phycoremediation for nutrient removal from wastewaters: a review