•Alkali and alkaline earth metals affect the pyrolysis products of lignin.•Alkali metals increased the yield of char and volatile aromatics.•Alkali metals are hypothesized to catalyze the cleavage of ...lignin linkages.
The effect of alkali and alkaline earth metals (AAEM) on fast pyrolysis of polysaccharides has been well documented. This paper examines the effect of AAEM on fast pyrolysis of lignin, which has not been as thoroughly investigated. Acetates of several metals were infused into organosolv cornstover lignin at a concentration of 1.0mmol AAEM cation per gram lignin followed by pyrolysis at 300–800°C.
One of the most notable effects was an increase in the yield of char with alkali metals producing more char than alkaline earth metals. Char yield was correlated to the electropositivity of the infused metal cations. Alkali metals increased the overall yield of volatile aromatic compounds while alkaline earth metals had the opposite effect.
The infusion of AAEMs into lignin led to an increase in methanol and a decrease in alkenyl side chains on the aromatic products. Methanol is hypothesized to result from cleavage of β-carbons from the 3‐hydroxyprop-1-enyl side chains of lignin linkages while the alkenyl side chains are hypothesized to result from cleavage of γ-carbons. Therefore, alkali metals appear to catalyze cleavage of linkages in the lignin structure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The objective of this study was to elucidate primary and secondary reactions of cellulose pyrolysis, which was accomplished by comparing results from a micro-pyrolyzer coupled to a GC–MS/FID system ...and a 100g/hr bench scale fluidized bed reactor system. The residence time of vapors in the micro-pyrolyzer was only 15–20ms, which precluded significant secondary reactions. The fluidized bed reactor had a vapor residence time of 1–2s, which is similar to full-scale pyrolysis systems and is long enough for secondary reactions to occur. Products from the fluidized bed pyrolyzer reactor were analyzed using a combination of micro-GC, GC–MS/FID, LC–MS and IC techniques. Comparison between the products from the two reactor systems revealed that the oligomerization of leglucosan and decomposition of primary products such as 5-hydroxymethyl furfural, anhydro xylopyranose and 2-furaldehyde were the major secondary reactions occurring in the fluidized bed reactor. This study can be used to build more descriptive pyrolysis models that can predict yield of specific compounds.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Depolymerization of cellulose offers the prospect of inexpensive sugars from biomass. Breaking the glycosidic bonds of cellulose to liberate glucose has usually been pursued by acid or enzymatic ...hydrolysis although a purely thermal depolymerization route to sugars is also possible. Fast pyrolysis of pure cellulose yields primarily the anhydrosugar levoglucosan (LG) whereas the presence of naturally occurring alkali and alkaline earth metals (AAEMs) in biomass strongly catalyzes ring‐breaking reactions that favor formation of light oxygenates. Here, we show a method of significantly increasing the yield of sugars from biomass by purely thermal means through infusion of certain mineral acids (phosphoric and sulfuric acid) into the biomass to convert the AAEMs into thermally stable salts (particularly potassium sulfates and phosphates). These salts not only passivate AAEMs that normally catalyze fragmentation of pyranose rings, but also buffer the system at pH levels that favor glycosidic bond breakage. It appears that AAEM passivation contributes to 80 % of the enhancement in LG yield while the buffering effect of the acid salts contributes to the balance of the enhancement.
Thermolytic sugars from biomass: Using a simple acid pretreatment, the catalytic activity of naturally occurring alkali and alkaline earth metals in lignocellulosic biomass is dramatically reduced, allowing the purely thermal production of sugars from biomass. The optimal amount of acid for the thermal depolymerization of biomass to sugars is proportional to the amount of alkali and alkaline earth metals inherently contained in the biomass feedstock.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, ...general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.
Generalized process diagram for bio-oil production and upgrading. Display omitted
► Two bio-oil upgrading pathways are investigated. ► Product yield, fixed capital cost, and biomass cost strongly ...affect facility IRR. ► Investment for commodity chemicals production is of low risk.
We evaluate the economic feasibility for two bio-oil upgrading pathways: two-stage hydrotreating followed by fluid catalytic cracking (FCC) or single-stage hydrotreating followed by hydrocracking. In the hydrotreating/FCC pathway, two options are available as the hydrogen source for hydrotreating: merchant hydrogen or hydrogen from natural gas reforming. The primary products of the hydrotreating/FCC pathway are commodity chemicals whereas the primary products for the hydrotreating/hydrocracking pathway are transportation fuels and hydrogen. The two pathways are modeled using Aspen Plus® for a 2000 metric tons/day facility. Equipment sizing and cost calculations are based on Aspen Economic Evaluation® software.
The bio-oil yield via fast pyrolysis is assumed to be 65% of biomass. We calculate the internal rate of return (IRR) for each pathway as a function of feedstock cost, fixed capital investment (FCI), hydrogen and catalyst costs, and facility revenues. The results show that a facility employing the hydrotreating/FCC pathway with hydrogen production via natural gas reforming option generates the highest IRR of 13.3%. Sensitivity analysis demonstrates that product yield, FCI, and biomass cost have the greatest impacts on facility IRR. Monte-Carlo analysis shows that two-stage hydrotreating and FCC of the aqueous phase bio-oil with hydrogen produced via natural gas reforming has a relatively low risk for project investment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Biocement production from microbially induced calcium carbonate precipitation (MICP) is an environmentally friendly approach for construction works, but the use of calcium chloride (CaCl2) in the ...conventional MICP process is a cost-limiting factor. The aim of this work is to develop a method for producing soluble calcium ions through two waste sources, limestone powder derived from aggregate quarries and acetic acid derived from fast pyrolysis of lignocellulosic biomass, as a replacement for the reagent grade CaCl2 in the MICP process. The ratio of limestone powder to acetic acid solution was optimized for a desirable calcium concentration with an appropriate pH. Procedures for applying the urease-producing bacteria, urea, and calcium solutions were developed for a successful MICP process and were treated for sand column test. The engineering properties of the biocemented sand, including water permeability, unconfined compressive strength, and tensile strength, were evaluated as a function of the calcium carbonate content of the product. It was found that the properties of the sand treated using the limestone/acetic acid derived calcium solution were comparable to those of sand treated using reagent grade CaCl2. Collectively, the results indicate that the new MICP process is effective, more sustainable, and cheaper compared with the conventional MICP method.
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IJS, KILJ, NUK, PNG, UL, UM
The Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study 2015 provides an up-to-date analysis of the burden of lower respiratory tract infections (LRIs) in 195 countries. This study ...assesses cases, deaths, and aetiologies spanning the past 25 years and shows how the burden of LRI has changed in people of all ages.
We estimated LRI mortality by age, sex, geography, and year using a modelling platform shared across most causes of death in the GBD 2015 study called the Cause of Death Ensemble model. We modelled LRI morbidity, including incidence and prevalence, using a meta-regression platform called DisMod-MR. We estimated aetiologies for LRI using two different counterfactual approaches, the first for viral pathogens, which incorporates the aetiology-specific risk of LRI and the prevalence of the aetiology in LRI episodes, and the second for bacterial pathogens, which uses a vaccine-probe approach. We used the Socio-demographic Index, which is a summary indicator derived from measures of income per capita, educational attainment, and fertility, to assess trends in LRI-related mortality. The two leading risk factors for LRI disability-adjusted life-years (DALYs), childhood undernutrition and air pollution, were used in a decomposition analysis to establish the relative contribution of changes in LRI DALYs.
In 2015, we estimated that LRIs caused 2·74 million deaths (95% uncertainty interval UI 2·50 million to 2·86 million) and 103·0 million DALYs (95% UI 96·1 million to 109·1 million). LRIs have a disproportionate effect on children younger than 5 years, responsible for 704 000 deaths (95% UI 651 000–763 000) and 60.6 million DALYs (95ÙI 56·0–65·6). Between 2005 and 2015, the number of deaths due to LRI decreased by 36·9% (95% UI 31·6 to 42·0) in children younger than 5 years, and by 3·2% (95% UI −0·4 to 6·9) in all ages. Pneumococcal pneumonia caused 55·4% of LRI deaths in all ages, totalling 1 517 388 deaths (95% UI 857 940–2 183 791). Between 2005 and 2015, improvements in air pollution exposure were responsible for a 4·3% reduction in LRI DALYs and improvements in childhood undernutrition were responsible for an 8·9% reduction.
LRIs are the leading infectious cause of death and the fifth-leading cause of death overall; they are the second-leading cause of DALYs. At the global level, the burden of LRIs has decreased dramatically in the last 10 years in children younger than 5 years, although the burden in people older than 70 years has increased in many regions. LRI remains a largely preventable disease and cause of death, and continued efforts to decrease indoor and ambient air pollution, improve childhood nutrition, and scale up the use of the pneumococcal conjugate vaccine in children and adults will be essential in reducing the global burden of LRI.
Bill & Melinda Gates Foundation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, ...general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.
As the use of carbon fibre reinforced polymers (CFRP) is continuing to increase in engineering applications, more functionalities will be required. Having an enhanced through-thickness electrical ...conductivity can be a useful functionality for CFRPs which will minimise their damage from lightning strikes, and will help in their real-time monitoring. For most modification methods there is an adverse effect on the manufacturing and the fibre volume fraction, which influence the mechanical properties of the resulting composites. Simultaneous improvement of multiple properties of CFRPs is difficult, and as such the ways in which different materials and processes improve properties of CFRPs need to be understood in depth. This review discusses research that attempts to improve the through-thickness electrical conductivity of CFRPs with interest in the effects on mechanical properties, specifically interlaminar fracture toughness. The last section discusses the effect and use of these methods to improve structural health monitoring (SHM) of CFRPs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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