217 research outputs found
Thermal extraction of bamboo with various solvents
This thesis is to describe the potential of improvement by liquefaction with various solvents in pyrolysis in terms of conversion of bamboo to gas and liquid and quality of the bio-oils and residues produced.
Fluidised sand bath and pressure gauge reactor were used for pyrolysis. The reactor was coupled with bamboo and a solvent and after 1 hour of pyrolysis and liquefaction at 410°C, the gas produced was collected in gas bag. To extract compounds uniformly from the chemically decomposed biomass mixture, soxhlet extraction was applied for between 17 and 20 hours. Then the residues were filtered. Solvents in the liquid were evaporated and distilled. Then, fractionation was performed and Gas Chromatography / Mass Spectrometry (GC-MS) was used to analyse the each fraction. Gas Chromatography (GC) and Elemental Analyser (EA) were used for analyses of the gas, bio-oil and residue.
The analytical results showed the liquefaction increased the overall conversion rate of bamboo to liquid and gas (13 -33% more than pyrolysis without using any solvents) and improved quality of the residues ( decreased O(%), increased H(%), H/O: 0.5 – 0.8, O/C: 0.5 -0.12, HHV:24 - 32 MJ/kg, ash content: 5 – 10%, ash free content: 12– 35 %) and bio-oils ( decreased O(%), increased H(%), H/C: 1 -2, O/C: 0 – 0.05, HHV: 38 – 48 MJ/kg). Solvents in the liquefaction carried out as carriers of H or donors preventing from a cross-linking effect. The highest conversion rate (around 90%) was shown in tetralin due to its high hydrogen donating nature.
The bio-oils are assumed as bitumen-like materials based on their dark brown colour, high viscosity and common functional groups with bitumen
Thermal extraction of bamboo with various solvents
This thesis is to describe the potential of improvement by liquefaction with various solvents in pyrolysis in terms of conversion of bamboo to gas and liquid and quality of the bio-oils and residues produced.
Fluidised sand bath and pressure gauge reactor were used for pyrolysis. The reactor was coupled with bamboo and a solvent and after 1 hour of pyrolysis and liquefaction at 410°C, the gas produced was collected in gas bag. To extract compounds uniformly from the chemically decomposed biomass mixture, soxhlet extraction was applied for between 17 and 20 hours. Then the residues were filtered. Solvents in the liquid were evaporated and distilled. Then, fractionation was performed and Gas Chromatography / Mass Spectrometry (GC-MS) was used to analyse the each fraction. Gas Chromatography (GC) and Elemental Analyser (EA) were used for analyses of the gas, bio-oil and residue.
The analytical results showed the liquefaction increased the overall conversion rate of bamboo to liquid and gas (13 -33% more than pyrolysis without using any solvents) and improved quality of the residues ( decreased O(%), increased H(%), H/O: 0.5 – 0.8, O/C: 0.5 -0.12, HHV:24 - 32 MJ/kg, ash content: 5 – 10%, ash free content: 12– 35 %) and bio-oils ( decreased O(%), increased H(%), H/C: 1 -2, O/C: 0 – 0.05, HHV: 38 – 48 MJ/kg). Solvents in the liquefaction carried out as carriers of H or donors preventing from a cross-linking effect. The highest conversion rate (around 90%) was shown in tetralin due to its high hydrogen donating nature.
The bio-oils are assumed as bitumen-like materials based on their dark brown colour, high viscosity and common functional groups with bitumen
How Learner-Centered Teaching is associated with Teacher Self-Efficacy and Job Satisfaction: Analysis of Data from 31 Countries
The expansion of learner-centered teaching has been the focus of education policy makers and teachers throughout the world. While most of the attention has been given to how learner-centered teaching influences student outcomes, it is important to consider how teachers are associated with learner-centered teaching. Using data from the OECD TALIS database, this study analyzes how the use of learner-centered teaching is associated with teacher self-efficacy and job satisfaction. Controlling for a wide range of teacher and classroom characteristics, as well as country and school fixed effects, we find that learner-centered teaching has a significant and positive association with both teacher self-efficacy and job satisfaction
Machine Learning Approaches for Estimating Forest Stand Height Using Plot-Based Observations and Airborne LiDAR Data
Effective sustainable forest management for broad areas needs consistent country-wide forest inventory data. A stand-level inventory is appropriate as a minimum unit for local and regional forest management. South Korea currently produces a forest type map that contains only four categorical parameters. Stand height is a crucial forest attribute for understanding forest ecosystems that is currently missing and should be included in future forest type maps. Estimation of forest stand height is challenging in South Korea because stands exist in small and irregular patches on highly rugged terrain. In this study, we proposed stand height estimation models suitable for rugged terrain with highly mixed tree species. An arithmetic mean height was used as a target variable. Plot-level height estimation models were first developed using 20 descriptive statistics from airborne Light Detection and Ranging (LiDAR) data and three machine learning approachessupport vector regression (SVR), modified regression trees (RT) and random forest (RF). Two schemes (i.e., central plot-based (Scheme 1) and stand-based (Scheme 2)) for expanding from the plot level to the stand level were then investigated. The results showed varied performance metrics (i.e., coefficient of determination, root mean square error, and mean bias) by model for forest height estimation at the plot level. There was no statistically significant difference among the three mean plot height models (i.e., SVR, RT and RF) in terms of estimated heights and bias (p-values > 0.05). The stand-level validation based on all tree measurements for three selected stands produced varied results by scheme and machine learning used. It implies that additional reference data should be used for a more thorough stand-level validation to identify statistically robust approaches in the future. Nonetheless, the research findings from this study can be used as a guide for estimating stand heights for forests in rugged terrain and with complex composition of tree species
Binary Replacement Technique for Application Programming Interface Level Simulation
International audienceDesign of complex embedded software requires ingenious solutions to many architectural problems. One such solution that would be a crucial catalyst in designing scalable and customized embedded software, is developed by API (Application Programming Interface) level simulator. The use of API level simulator has been gaining wide acceptance due to its design and verification efficiency by enabling parallel development in multiple software layers. However, there are two major bottlenecks in realizing practical systems: source code modification and recompilation of the target software. The paper proposes a novel simulation technique to resolve these two critical issues. The proposed technique makes it possible to replace any part of the target binary without modifying its source code and recompiling it
Effects of Aromatherapy on Stress, Sleep, Nausea and Vomiting during Patient Controlled Analgesia Treatment of Patients with Hysterectomy
PURPOSE: The purpose of study was to examine effects of aromatherapy on stress, sleep, nausea and vomiting of women after laparoscopic hysterectomy.
METHODS: The participants were 60 women who had laparoscopic hysterectomy: experiment group for aromatherapy (n=30) and control group for routine care (n=30). The experimental group received inhalation aromatherapy for 5 minutes, twice; the first was done right after the operation, the second was at 9 pm before sleep on the same day--while the control group had no inhalation. Data were collected from July to September, 2012 at G hospital.
RESULTS: The degree of psychological stress was not significantly different between two groups (t=-1.96, p= .054). Yet, there were significant differences between two groups for degree of physiological stress (t=-3.20, p= .002), the level of cortisol (t=-2.01, p= .049), the score of sleep status (t=2.47, p= .016), the score of sleep satisfaction (t=2.43, p= .018), and the score for nausea and vomiting (t=-2.58, p= .012).
CONCLUSION: Inhalation aromatherapy using the mixed oil of lavender, mandarin, and marjoram was effective in decreasing the level of physiological stress, cortisol, and the score for nausea and vomiting, and also allowed the participants to have a better sleep. Therefore, inhalation aromatherapy could be effective in improving the quality of life of these women during recovery
The Impact of Project-Based Learning on Teacher Self-Efficacy
The expansion of project-based learning has been advocated for as a solution and reform measure to the problem of rote learning-based teaching practices in Korean schools, deemed unfit for the development of diverse skills needed in the 21st century. While the ultimate goal of initiating project-based learning is to affect students in positive ways, it is important to analyze how conducting project-based learning affects teachers, as they are the direct implementers of teaching practices and are bound to have immense influence on the overall learning experience of students. By using the OECD TALIS database, we show that conducting project-based learning is strongly and positively associated with teacher self efficacy. Such results are in line with an analysis using data obtained from a field experiment on teacher training of project-based learning conducted on Daegu city middle schools
Acupuncture for Spasticity after Stroke: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
The aim of this systematic review was to determine how effective acupuncture or electroacupuncture (acupuncture with electrical stimulation) is in treating poststroke patients with spasticity. We searched publications in Medline, EMBASE, and the Cochrane Library in English, 19 accredited journals in Korean, and the China Integrated Knowledge Resources Database in Chinese through to July 30, 2013. We included randomized controlled trials (RCTs) with no language restrictions that compared the effects of acupuncture or electroacupuncture with usual care or placebo acupuncture. The two investigators assessed the risk of bias and statistical analyses were performed. Three RCTs in English, 1 in Korean, and 1 in Chinese were included. Assessments were performed primarily with the Modified Ashworth Scale (MAS). Meta-analysis showed that acupuncture or electroacupuncture significantly decreased spasticity after stroke. A subgroup analysis showed that acupuncture significantly decreased wrist, knee, and elbow spasticity in poststroke patients. Heterogeneity could be explained by the differences in control, acupoints, and the duration after stroke occurrence. In conclusion, acupuncture could be effective in decreasing spasticity after stroke, but long-term studies are needed to determine the longevity of treatment effects
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