• Advances in environmental research
• /
• v.6 no.2
• /
• pp.95-111
• /
• 2017

The valorization of swine manure samples, i.e., de-watered cake (SMc) and solid digestate (SMd), in products with beneficial value, i.e., low cost activated carbons (ACs), is studied. For this purpose slow pyrolysis and steam activation at three different duration times are applied. Additionally, the obtained ACs are characterized and tested towards removal of Cr(VI) from aqueous solutions. It is revealed that BET surface area varies in the range of $236-267m^2/g$ for ACs prepared from SMc sample and in the range of $411-432m^2/g$ for ACs prepared from SMd sample. Despite the low determined surface area of prepared ACs, a high total Cr removal capacity is observed occurring through a "coupled adsorption-reduction" mechanism. Higher Cr(VI) removal capacity is demonstrated for ACs having higher surface area ($q_m$ is 140.9 mg/g according Langmuir modelling). Cr(VI) removal is found to be pH dependent with a maximum at pH 1. However at that pH significant amounts of Cr remain in the solution as Cr(III). At pH 2 lower amount of Cr(VI) is removed compensated by a higher removal of Cr(III) resulting in a higher amount of adsorbed $Cr_{tot}$. Therefore adsorption at pH 2 is found to be appropriate. The removal capacity of the studied ACs towards Cr(VI) is almost independent of activation time.

• Applied Chemistry for Engineering
• /
• v.3 no.1
• /
• pp.130-137
• /
• 1992

The Graft copolymerization of acrylonitrile(AN) and styrene(ST) onto chloroprene rubber(CR) were carried out with benzoyl peroxide(BPO) as an initiator. The synthesized graft copolymer(ACS) was separated from polymeric mixture by the extraction with ethyl acetate and n-hexane, acetone and methanol, dimethylformamide(DMF) and methanol mixed solvent systems. The graft copolymer obtained, acrylonitrile-chloroprene-styrene(ACS) was identified by IR spectrophotometer. The effect of mole ratio of styrene to acrylonitrile, reaction time and temperature, initiator concentration, CR content and solvents on graft copolymerization were examined. It was observed that the grafting efficiency increased with [ST]/[AN] mole ratio and reaction time. The grafting efficiency increased with increasing initiator concentration and CR content. The maximum grafting efficiency was obtained when the mole ratio of [ST]/[AN] was 1.5 and reaction was made at 40hrs, and $70^{\circ}C$ using chloroform/toluene mixed solvent. The thermal properties, light resistance and flammability of ACS were compared with those of ABS and AES. It was found that flame retardancy of related polymers increased in the order ACS>ABS>AES. The thermal stability of ACS was greatly improved when compared with ABS or AES. Morphology of ACS was also investigated by using a transmisson electron microscope(TEM).

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.11
• /
• pp.1516-1521
• /
• 2009

This study was carried out to estimate beneficial effects of medicinal plant [Oenanthe javanica (MNR), Coicis lachryma-jobi L. var. (YM), Plantaginis asiatica L. (CJJ)] water extracts on activities of key enzymes such as lipoprotein lipase (LPL), acyl-CoA synthetase (ACS) and carnitine acetyltransferase (CAT) on lipid metabolism. LPL and ACS were extracted from the epididymal adipose tissue and liver of Zucker lean rats (lean) and Zucker fatty rats (fa/fa). MNR or YM water extract treatment significantly reduced the activity of lean and fa/fa LPL. When 10000 ppm of MNR, YM, and CJJ water extracts were tested, they decreased fa/fa LPL activity by 32.5%, 30.1% and 22.8%, respectively. The lean ACS activity was significantly higher in YM water extract treatment compared to the control and the MNR water extract treatment significantly increased the activity of fa/fa ACS, compared to the activity in the control (p<0.05). MNR water extract activated fa/fa ACS activity by 12-fold compared with control at 10000 ppm concentration. CAT activity was significantly higher in 10000 ppm and 20000 ppm CJJ water extract treatment than in the control. Thus, the MNR, YM and CJJ water extracts may have beneficial effects due to activities of enzymes related with fat metabolism in obese humans.

• Journal of Power Electronics
• /
• v.16 no.1
• /
• pp.227-237
• /
• 2016

A novel digital current control strategy for digitally controlled DC-DC switching converters, referred to as Adjacent Cycle Sampling (ACS), is proposed in this paper. For the ACS current control strategy, the available time interval from sampling the current to updating the duty ratio, is approximately one switching cycle. In addition, it is independent of the duty ratio. As a result, the contradiction between the processing speed of the hardware and the transient response speed can be effectively relaxed by using the ACS current control strategy. For digitally controlled buck DC-DC switching converters with trailing-edge modulation, digital current control algorithms with the ACS control strategy are derived for three different control objectives. These objectives are the valley, average, and peak inductor currents. In addition, the sub-harmonic oscillations of the above current control algorithms are analyzed and eliminated by using the digital slope compensation (DSC) method. Experimental results based on a FPGA are given, which verify the theoretical analysis results very well. It can be concluded that the ACS control has a faster transient response speed than the time delay control, and that its requirements for hardware processing speed can be reduced when compared with the deadbeat control. Therefore, it promises to be one of the key technologies for high-frequency DC-DC switching converters.

• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.3
• /
• pp.215-221
• /
• 2009

Nuclear myocardial perfusion imaging is very effective in the evaluation of patients with suspicious acute coronary syndrome (ACS), for adequate diagnosis and treatment. There have been many clinical evidences to support the efficacy and cost-effectiveness. In addition, many authoritative guidelines support the utility of myocardial perfusion imaging in ACS with an appropriate diagnostic protocol. However, with the development of other cardiac imaging modalities, the choice of modality for the diagnosis of suspicious ACS now depends on the availability of each modality in each institute. Newly developed imaging technologies, especially including molecular imaging, are expected to have great potential not only for diagnosis but also for primary, secondary, and tertiary prevention of ACS.

• Polymer(Korea)
• /
• v.36 no.6
• /
• pp.756-760
• /
• 2012

In this work, the coal tar pitch-based activated carbons (ACs) were prepared by KOH activation for electrode materials of supercapacitor. The effects of activation temperature on electrochemical performance of the ACs were investigated with cyclic voltammogram (CV) measurement. The textural and morphological properties of the ACs were measured by adsorption isotherms and field emission scanning electron microscope (FE-SEM) analyses, respectively. The experimental results indicated that the specific capacitance of the ACs increased with developing the micropore volume by activation temperature. As a result the specific capacitance of the ACs increased, owing to the development of micro pore volume of the ACs.

• Korean Chemical Engineering Research
• /
• v.50 no.6
• /
• pp.1043-1048
• /
• 2012

In this study, activated carbons (ACs) were modified as electrode materials for an electric double layer capacitor (EDLC) by controlling oxygen- and nitrogen-containing functional groups. The morphological and chemical properties of ACs were analyzed through scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectrometer, automatic elemental analyzer (EA) and Boehm titration. Also, charge/discharge tests were performed to investigate the EDLC performance. Oxygen- and nitrogen-containing functional groups were introduced on the surface of ACs through acid and urea treatments, respectively. ACs with nitrogen-containing functional groups showed 2 mA increase of gravimetric discharge capacity and quick achievement of maximum charge/discharge performance. However, ACs with oxygen-containing functional groups showed low discharge capacity and its gradual decrease during further cyclic test, since the functional groups interrupted adsorption/desorption of charges in the electrolyte on the surface of ACs.

• Journal of Preventive Medicine and Public Health
• /
• v.51 no.2
• /
• pp.71-82
• /
• 2018

Objectives: Areca nut is widely consumed in many parts of the world, especially in South and Southeast Asia, where cardiovascular disease (CVD) is also a huge burden. Among the forms of CVD, acute coronary syndrome (ACS) is a major cause of mortality and morbidity. Research has shown areca nut chewing to be associated with diabetes, hypertension, oropharyngeal and esophageal cancers, and CVD, but little is known about mortality and re-hospitalization secondary to ACS among areca nut users and non-users. Methods: A prospective cohort was studied to quantify the effect of areca nut chewing on patients with newly diagnosed ACS by categorizing the study population into exposed and non-exposed groups according to baseline chewing status. Cox proportional hazards models were used to examine the associations of areca nut chewing with the risk of re-hospitalization and 30-day mortality secondary to ACS. Results: Of the 384 ACS patients, 49.5% (n=190) were areca users. During 1-month of follow-up, 20.3% (n=78) deaths and 25.1% (n=96) re-hospitalizations occurred. A higher risk of re-hospitalization was found (adjusted hazard ratio [aHR], 2.05; 95% confidence interval [CI], 1.29 to 3.27; p=0.002) in areca users than in non-users. Moreover, patients with severe disease were at a significantly higher risk of 30-day mortality (aHR, 2.77; 95% CI, 1.67 to 4.59; p<0.001) and re-hospitalization (aHR, 2.72; 95% CI, 1.73 to 4.26; p<0.001). Conclusions: The 30-day re-hospitalization rate among ACS patients was found to be significantly higher in areca users and individuals with severe disease. These findings suggest that screening for a history of areca nut chewing may help to identify patients at a high risk for re-hospitalization due to secondary events.

• Journal of Chest Surgery
• /
• v.38 no.11 s.256
• /
• pp.746-760
• /
• 2005

Background: Following the implantation of heart valve prostheses, it is important to maintain therapeutic INR to reduce the risk of thromboembolism. The objectives of this study were to determine the causes of nontherapeutic INRs, and to identify the factors associated with nonadherences to warfarin therapy in Korean outpatients with prosthetic heart valves managed by a pharmacist-run anticoagulation service (ACS). Material and Method: A retrospective chart review was completed for all patients enrolled in the ACS at Seoul National University Hospital from March, 1997b to September, 2000. The data on 868 patients (5,304 visits) who were at least 6 months post-valve replacement were included. All possible causes of nontherapeutic INRs were documented for each patient visit. The association of covariates to noncompliance was investigated by univariate analysis. Result: The reasons for nontherapeutic INRs were identified as follows: inadequate dosage adjustment $(21\%)$, nonadherences to dosing regimen $(13\%)$, drug/herbal interactions $(12\%)$, changes in diet $(7\%)$, and indeterminate cause $(42\%)$. Younger age, shorter duration of ACS and longer duration of warfarin therapy were associated with nonadherence. Conclusion: In this study, nonadherence and interactions between diet and medications were found to be important factors influencing nontherapeutic INRs. Longer duration of enrollment in the ACS affected the adherence to warfarin therapy Positively whereas younger age and longer duration of warfarin therapy affected negatively.

• Journal of Construction Engineering and Project Management
• /
• v.7 no.2
• /
• pp.1-10
• /
• 2017

The Clonal Selection Algorithm (CSA) is an algorithm inspired by the human immune system mechanism. In CSA, several parameters needs to be optimized by large amount of sensitivity analysis for the optimal results. They limit the accuracy of the results due to the uncertainty and subjectivity. Adaptive Clonal Selection (ACS), a modified version of CSA, is developed as an algorithm without controls by pre-defined parameters in terms of selection process and mutation strength. In this paper, we discuss the ACS in detail and present its implementation in construction site utilization planning (CSUP). When applied to a developed model published in research literature, it proves that the ACS are capable of searching the optimal layout of temporary facilities on construction site based on the result of objective function, especially when the parameterization process is considered. Although the ACS still needs some improvements, obtaining a promising result when working on a same case study computed by Genetic Algorithm and Electimze algorithm prove its potential in solving more complex construction optimization problems in the future.