Literature review of physical and chemical pretreatment processes for lignocellulosic biomass

Different pretreatment technologies published in public literature are described in terms of the mechanisms involved, advantages and disadvantages, and economic assessment. Pretreatment technologies for lignocellulosic biomass include biological, mechanical, chemical methods and various combinations thereof. The choice of the optimum pretreatment process depends very much on the objective of the biomass pretreatment, its economic assessment and environmental impact. Only a small number of pretreatment methods has been reported as being potentially cost-effective thus far. These include steam explosion, liquid hot water, concentrated acid hydrolysis and dilute acid pretreatments

An evaluation of the accounting rate of return : evidence for Dutch quoted firms

Although the accounting rate of return (ARR) is traditionally regarded as an important profitability measure in ratio analysis, there has been relatively little theoretical and empirical analysis on its statistical properties and its intrinsic ability to explain market returns. This paper provides an empirical examination of the distributional properties and a time-series analysis of the ARR’s of listed Dutch companies for the years from 1978 to 1997. Furthermore we examine how the ARR is related to market return and risk. We investigate the distributional properties of the accounting rate of return. Our study confirms prior international research which concludes that ARR follows a non-normal distribution. Previous US and UK studies suggest that time series earnings or ARR can be characterized by a random walk or a mean-reverting process. The time series results of our sample are characterized by mean reversion. This paper extends the empirical research on ARR by deriving a panel data analysis that yields more reliable estimates. Researchers using US data found that the ARR was deficient as a representation of market returns and was not related to systematic risk. We find the opposite.

Valorisation of lignin – Achievements of the LignoValue project

Lignocellulosic biorefinery for production of biofuels, materials and chemicals requires valorization of all fractions including lignin. As a consequence of its poly-aromatic structure, lignin potentially serves as a source for aromatic chemicals. The developed biorefinery concept of the LignoValue project comprises two major steps: (1) Organosolv fractionation of wheat straw and willow into (hemi)cellulose and high purity lignin. (2) Further conversion of the isolated lignin via catalytic pyrolysis, supercritical depolymerization and partial hydrodeoxygenation (HDO) into different components like low molecular phenolic compounds, wood adhesives and fuel additives. The cellulose fraction resulting after organosolv fractionation is effectively hydrolysed by enzymes for biofuel production. Quality assessment of the liberated lignins shows interesting characteristics for follow-up chemistry such as high purity, relatively low molar mass and polydispersity. Catalytic pyrolysis in a fluidised bed at 400-500°C was found to convert organosolv lignin in 35-55% phenolic oil, 10% identified monomeric phenolic compounds, 10-20% water, 5-20% gas and 35-55% char. Supercritical depolymerisation of lignin in carbon dioxide based solvents resulted in a similar spectrum of products, however, at a lower temperature (ca 300°C) but at higher pressures. In both thermochemical processes the use of promotors or catalysts lead to an improved yield of the target monomeric aromatic products. Also the residual char fraction shows interesting properties for use in bio-char applications. Catalytic semi-continuous HDO of lignin in hydrogen atmosphere can be manipulated to yield both light oils or heavy oils as potential additives to fuels. Suitable catalysts were found to convert depolymerised lignin to phenolic oils in high yields. In this process no char formation is observed. The lignin oils were successfully tested on lab scale as partial substitution of phenol in resins for gluing wood panels. The LignoValue concept is critically reviewed in a techno-economic analysis demonstrating the potential for further commercial development and adoptation of this innovative biorefinery process in Europe

Relationships between adolescent students’ reading skills, historical content knowledge and historical reasoning ability

The ability to apply various reading skills is an important prerequisite to comprehend expository texts commonly found in history textbooks, but it is unclear which specific skills contribute to students’ historical content knowledge and historical reasoning abilities. This study used a digital learning environment (DLE) to measure and support lower secondary students’ subject-specific reading skills, and explored the relationships with students’ historical content knowledge and historical reasoning ability. Results showed that subject-specific reading skills, such as explaining historical events, correlated significantly with both historical content knowledge and historical reasoning ability, but not all skills were significant predictors. These findings indicate that to promote the advanced practice of historical reasoning, history teachers should pay attention to students’ reading comprehension skills

Relationships between adolescent students’ reading skills, historical content knowledge and historical reasoning ability

The ability to apply various reading skills is an important prerequisite to comprehend expository texts commonly found in history textbooks, but it is unclear which specific skills contribute to students’ historical content knowledge and historical reasoning abilities. This study used a digital learning environment (DLE) to measure and support lower secondary students’ subject-specific reading skills, and explored the relationships with students’ historical content knowledge and historical reasoning ability. Results showed that subject-specific reading skills, such as explaining historical events, correlated significantly with both historical content knowledge and historical reasoning ability, but not all skills were significant predictors. These findings indicate that to promote the advanced practice of historical reasoning, history teachers should pay attention to students’ reading comprehension skills

Advanced mineral carbonation: An approach to accelerate CO\u3csub\u3e2\u3c/sub\u3e sequestration using steel production wastes and integrated fluidized bed reactor

© Springer Nature Switzerland AG 2019. Industrial pollution is the major source of global warming through emissions of greenhouse gases (GHG’s) like CO2, CH4, and NO2, causing noticeable increasing in the world’s temperature. Mineral carbonation is a method of carbon capture and storage (CCS) through which CO2 is sequestered with advantage of permanent sequestration and no need for post-storage surveillance and monitoring through stabilizing the reactive mineral wastes released from metal industries. This paper applied a simple and an inexpensive hydration process as a pre-treatment step for the carbonation of Ladle Furnace (LF) slag, one of the steel production by-products in UAE, followed by direct gas-solid carbonation in a new designed integrated fluidized bed reactor (FBR). About (10–15)% by weight of produced steel, alkaline solid residues were generated, based on the characteristics of the manufacturing process. The integrated FBR was designed to control the flow rate up to 50 l/min with step accuracy of 0.1 l/min, and temperature up to 200 °C through a double jacket electrical heater. Operating pressure can be adjusted up to 6 bars. All parameters are monitored by SCADA system. A mixture gas of 10% CO2, balanced with air, was used to perform the carbonation process and evaluation the carbonation efficiency as well. A gas analyzer installed at the outlet of FBR was used to measure unreacted CO2 gas after leaving the reactor, and calculate the amount of CO2 captured accordingly. Results of analytical techniques like TGA and XRD emphasized the sequestration of CO2 and show a high efficient carbonation process

Prevalence and Prognostic Significance of Extramural Venous Invasion in Patients with Locally Advanced Esophageal Cancer

BACKGROUND: Extramural venous invasion (EMVI) is a known adverse prognostic factor in patients with colorectal carcinoma. The prevalence and significance of EMVI in esophageal cancer (EC) patients is still unclear. METHODS: From a prospectively maintained database, we retrospectively reviewed the resection specimens of patients with pathologic locally advanced (pT3/T4/N0-3) EC who were treated with curative intent between 2000 and 2015. Patients with previous malignancies and gastroesophageal junction (type II/III) tumors were excluded. Included were 81 patients who underwent surgery alone and 37 patients who underwent neoadjuvant chemoradiotherapy (nCRT). EMVI was assessed on hematoxylin and eosin slides and confirmed or excluded by additional Elastica van Gieson staining. Survival was analyzed using a multivariable Cox regression. RESULTS: EMVI was present in 23.5% (n = 19) of patients in the surgery-alone group and 21.6% (n = 8) of patients in the nCRT group. The prevalence of EMVI after surgery alone was significantly high in squamous cell carcinomas and among tumors located in the mid-esophagus, as well as those with lymphovascular invasion (p  pT3/N0-3 EC patients, EMVI was present in 23.5% of patients in the surgery-alone group and in 21.6% of patients after nCRT. EMVI was an independent adverse prognostic factor in patients after surgery alone

Biochemical and Structural Characterization of a Uronic Acid Oxidase from Citrus sinensis

Aldaric acids are attractive diacids that can be prepared by selective oxidation of carbohydrates. For this, effective biocatalysts are in demand. This work reports on the discovery, biochemical and structural characterization of a VAO-type flavin-containing carbohydrate oxidase from Citrus sinensis: URAOCs3. URAOCs3 could be overexpressed using prokaryotic and eukaryotic expression systems. Extensive biochemical characterization revealed that the enzyme displays a high thermostability and an exquisite selectivity for uronic acids, galacturonic acid and glucuronic acid. The enzyme was further investigated by determining the crystal structure. The selective oxidation of D-galacturonic acid in a complex mixture was demonstrated, showing how URAOCs3 was found to be highly effective in selectively producing galactaric acid while leaving other carbohydrates untouched. In addition to the specific discovery of URAOCs3, these findings suggest that plant proteomes can be an interesting source for new biocatalysts.</p