Improvement of Cold Filter Plugging Point of Jatropha-Corn Biodiesel Blend Using Acrylic Copolymer

Theaim of this study is to investigate the influence of fatty acid compositions in biodiesel on some parameters such as the oxidation stability, iodine value and cold flow properties. Edible oil is represented byrefined corn oil and non-edible oil represented by jatropha curcas oil. In order to overcome the shortcomings of jatropha-corn biodiesel, acrylic copolymer is introduced as a Cold Flow Improvers (CFIs) additive to reduce the cold filter plugging point (CFPP). Crude jatropha oil was pre-treated to minimize the high free fatty acid content. The treated jatropha oil and refined corn oil were then transesterificated using sodium methoxide,CH3ONa as catalyst at standard reaction conditions (reaction time, 1.5 h; weight of catalyst 1 wt.% of initial oil weight; molar ratio methano:oil/ 6:1; reaction temperature, 64°C) to produce jatropha methyl ester (JME) and corn methyl ester (CME) respectively. The biodiesel is then blended at different mass ratios. Each jatropha-corn biodiesel blend parameters such oxidation stability, iodine value, density, calorific value, fatty acid content and cold flow properties are investigated. The biodiesel was tested accordingly to the standard UNEEN 14214 for quality assurance. Results show that ratio blend CME:JME (20:80) gives 6.42 hours of oxidation stability and -2°C for CFPP which complies with the EN 14214 standards. Acrylic copolymer as CFI is then added to the same blend ratio to reduce the CFPP. CFI successfully reduced the CFPP from -2°C to -6°C which gives better cold flow properties to the corn-jatrophabiodiesel blend

Improvement of Cold Filter Plugging Point of Jatropha-Corn Biodiesel Blend Using Acrylic Copolymer

Theaim of this study is to investigate the influence of fatty acid compositions in biodiesel on some parameters such as the oxidation stability, iodine value and cold flow properties. Edible oil is represented byrefined corn oil and non-edible oil represented by jatropha curcas oil. In order to overcome the shortcomings of jatropha-corn biodiesel, acrylic copolymer is introduced as a Cold Flow Improvers (CFIs) additive to reduce the cold filter plugging point (CFPP). Crude jatropha oil was pre-treated to minimize the high free fatty acid content. The treated jatropha oil and refined corn oil were then transesterificated using sodium methoxide,CH3ONa as catalyst at standard reaction conditions (reaction time, 1.5 h; weight of catalyst 1 wt.% of initial oil weight; molar ratio methano:oil/ 6:1; reaction temperature, 64°C) to produce jatropha methyl ester (JME) and corn methyl ester (CME) respectively. The biodiesel is then blended at different mass ratios. Each jatropha-corn biodiesel blend parameters such oxidation stability, iodine value, density, calorific value, fatty acid content and cold flow properties are investigated. The biodiesel was tested accordingly to the standard UNEEN 14214 for quality assurance. Results show that ratio blend CME:JME (20:80) gives 6.42 hours of oxidation stability and -2°C for CFPP which complies with the EN 14214 standards. Acrylic copolymer as CFI is then added to the same blend ratio to reduce the CFPP. CFI successfully reduced the CFPP from -2°C to -6°C which gives better cold flow properties to the corn-jatrophabiodiesel blend

An endoglucanase, GsCelA, from Geobacilus sp. undergoes an intriguing self- truncation process for enhancing activity and thermostability

An endoglucanase, GsCelA, was isolated and cloned from a thermophilic Geobacillus sp. 70PC53 grown in a rice straw compost in southern Taiwan. It was observed that highly purified GsCelA was able to self-truncate, removing a segment of 53 amino acid residues from its C-terminus. The purified GsCelA does not possess any protease activity and this self-truncation process is insensitive to standard protease inhibitors except EDTA and EGTA. This unique self-truncation process takes place at a temperature higher than 10C with an optimal pH between 6-7, and can be further enhanced with certain divalent ions such as Ca+2 and Mg+2. Crystal structure of GsCelA has a typical TIM-barrel configuration with 8 alpha-helices and 8 beta-strands, but with the presence of a divalent ion. Mutations of amino acids residues surrounding this metal ion do not affect the self-truncation process, but some of these mutants have enhanced enzymatic activities. Mutation of the cleavage site between K315 and G316 does not affect the self-truncation process. However, a deletion of ten amino acids near the cleavage site, i.e. from amino acid 310 to 320, slows down the truncation process but does not block it, and a truncated form around 315 amino acids in length eventually appears. This intriguing observation indicates that the self-truncation process is not site specific, but capable of measuring 315 amino acids from the N-terminus as the cleavage site. This self-truncation process also occurs in the native host of this enzyme, Geobacillus sp. 70PC53, with almost all secreted form of this enzyme being self-truncated. The 53 amino-acid-long C-terminal segment removed by this self-truncation process has binding affinity toward both crystal and amorphous cellulose as well as the s cell walls, yet its sequence bears no apparent homology to any known carbohydrate binding motifs. Various other mutation analyses and the structure-based recombination process, SCHEMA, have been carried out, and both the activity and thermostabilty of this enzyme are further improved. The truncated and improved GsCelA has almost twice the activity as the un-truncated form, and its thermostability is also further enhanced with T50 reaching 86C and TA50 higher than 100C, making this enzyme extremely useful in industrial processes carried out at high temperatures, such as the pre-treatment of cellulosic animal feeds during the final drying step. This research was supported by grants from Taiwan Ministry of Science and Technology and from Academia Sinica

What is comprehensive school eye health?

Education has the potential to change individuals’ lives and fuel social transformation. There is a strong link between children’s health, including their visual health, and the quality of their learning and achievement at school. This, in turn, affects children’s future quality of life and economic productivity. School eye health programmes provide a unique opportunity to deliver comprehensive eye health services to school-going children

WinoQueer: A Community-in-the-Loop Benchmark for Anti-LGBTQ+ Bias in Large Language Models

We present WinoQueer: a benchmark specifically designed to measure whether large language models (LLMs) encode biases that are harmful to the LGBTQ+ community. The benchmark is community-sourced, via application of a novel method that generates a bias benchmark from a community survey. We apply our benchmark to several popular LLMs and find that off-the-shelf models generally do exhibit considerable anti-queer bias. Finally, we show that LLM bias against a marginalized community can be somewhat mitigated by finetuning on data written about or by members of that community, and that social media text written by community members is more effective than news text written about the community by non-members. Our method for community-in-the-loop benchmark development provides a blueprint for future researchers to develop community-driven, harms-grounded LLM benchmarks for other marginalized communities.Comment: Accepted to ACL 2023 (main conference). Camera-ready versio

A Comparison of Lex Bounds for Multiset Variables in Constraint Programming

Set and multiset variables in constraint programming have typically been represented using subset bounds. However, this is a weak representation that neglects potentially useful information about a set such as its cardinality. For set variables, the length-lex (LL) representation successfully provides information about the length (cardinality) and position in the lexicographic ordering. For multiset variables, where elements can be repeated, we consider richer representations that take into account additional information. We study eight different representations in which we maintain bounds according to one of the eight different orderings: length-(co)lex (LL/LC), variety-(co)lex (VL/VC), length-variety-(co)lex (LVL/LVC), and variety-length-(co)lex (VLL/VLC) orderings. These representations integrate together information about the cardinality, variety (number of distinct elements in the multiset), and position in some total ordering. Theoretical and empirical comparisons of expressiveness and compactness of the eight representations suggest that length-variety-(co)lex (LVL/LVC) and variety-length-(co)lex (VLL/VLC) usually give tighter bounds after constraint propagation. We implement the eight representations and evaluate them against the subset bounds representation with cardinality and variety reasoning. Results demonstrate that they offer significantly better pruning and runtime.Comment: 7 pages, Proceedings of the Twenty-Fifth AAAI Conference on Artificial Intelligence (AAAI-11

Enhancement of activity and thermostability of a Geobacillus endoglucanase via a unique self-truncation process

The complete utilization of lignocellulosic biomass requires the hydrolysis of cellulose fibers via the synergistic action of three enzymes: exoglucanase, endoglucanase and beta-glucosidase. GsCelA is a 368-amino-acid endoglucanase secreted from a thermophilic Geobacillus sp. 70PC53 that was isolated form a rice straw compost in south Taiwan. GsCelA belongs to the glycosyl hydrolase family 5 and has a typical TIM barrel structure. This enzyme has excellent lignocellulolytic activity and high thermostability, with optimal temperature at 60℃ and pH at 5.0. The purified GsCelA is capable of carrying out a unique self-truncation process at temperature higher than 10 ℃ with optimal pH at 6-7. This self-truncation process is not due to the action of contaminating proteases and it can be suppressed by EDTA and EGTA, and enhanced by divalent metal ions. This self-truncation process also takes place in vivo in Geobacillus sp. 70PC53. The spontaneous or engineered C-terminal truncation up to 60 amino acids from the C-terminus improves GsCelA specific activity and renders the enzyme more thermostable. To investigate the importance of specific amino acids on the enzymatic activity of GsCelA, site-directed mutagenesis and protein engineering approach were employed to alter amino acid residues unique to this enzyme. It was demonstrated that point mutations Y195T , D55S, G288T and D289L replacements increase the activity of this enzyme by 30%

Moderate Alcohol Use and Mortality from Ischaemic Heart Disease: A Prospective Study in Older Chinese People

Abstract Background: Moderate alcohol use is generally associated with lower ischaemic heart disease (IHD) mortality but it is difficult to ascertain whether this is due to attributes of moderate alcohol users or the properties of alcohol itself. Evidence from populations with different patterns of alcohol use and IHD can provide crucial evidence. We assessed the association of moderate alcohol use with IHD mortality in older Chinese people from Hong Kong. Methodology We used Cox regression to determine whether moderate alcohol use was associated with IHD mortality in a prospective, population-based cohort study of all 56167 attendees, aged 65 years or over, from July 1998 to December 2000 at all 18 Elderly Health Centers operated by the Department of Health in Hong Kong. Principal Findings After a median follow-up of 4.2 years, there were 406 (188 in men, 218 in women) deaths from IHD in 54,090 subjects (96.3% successful follow-up). Moderate alcohol use in men was not associated with IHD mortality adjusted only for age [Hazard Ratio, HR 1.01 (95% CI 0.55 to 1.84) compared with never drinkers] or additionally adjusted for socioeconomic status and lifestyle. Almost all women were occasional drinkers and their current alcohol use was not significantly associated with IHD mortality [HR 0.88, (95% CI 0.51 to 1.53)]. Conclusions Moderate alcohol use had no effect on IHD mortality in older Chinese men. Lack of replication of the usual protective effect of moderate alcohol use in a setting with a different pattern of alcohol use and IHD could be due to chance or could suggest that the protective effect of alcohol on IHD does not extend to all populations

Thermocurrents and their Role in high Q Cavity Performance

Over the past years it became evident that the quality factor of a superconducting cavity is not only determined by its surface preparation procedure, but is also influenced by the way the cavity is cooled down. Moreover, different data sets exists, some of them indicate that a slow cool-down through the critical temperature is favourable while other data states the exact opposite. Even so there where speculations and some models about the role of thermo-currents and flux-pinning, the difference in behaviour remained a mystery. In this paper we will for the first time present a consistent theoretical model which we confirmed by data that describes the role of thermo-currents, driven by temperature gradients and material transitions. We will clearly show how they impact the quality factor of a cavity, discuss our findings, relate it to findings at other labs and develop mitigation strategies which especially addresses the issue of achieving high quality factors of so-called nitrogen doped cavities in horizontal test