• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.786-789
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• 1989

A nonlinear self-tuning regulator for a neutralization process of a weak acid and strong base system is proposed. Rearranging the state equation of the process model, we first obtain equations which are linear for a manipulated variable or unknown parameters. Then to these equations we apply the standard procedure used in designing linear self-tuning regulators. Simulation results show that the regulator provides very good performances for various realistic situations and traces variations of the unknown parameters. Since computations are simple and additional measurements except the effluent pH value are only flow rates of influent streams, it can be easily applied to real processes such as a waste water treatment process.

• Korean Journal of Materials Research
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• v.24 no.11
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• pp.578-584
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• 2014

To synthesize Sn nanoparticles (NPs) less than 30 nm in diameter, a modified polyol process was conducted at room temperature using a reducing agent, and the effects of different pH values of the initial solutions on the morphology and size of the synthesized Sn NPs were analyzed. tin(II) 2-ethylhexanoate, diethylene glycol, sodium borohydride, polyvinyl pyrrolidone (PVP), and sodium hydroxide were used as a precursor, reaction medium, reducing agent, capping agent, and pH adjusting agent, respectively. It was found by transmission electron microscopy that the morphology of the synthesized Sn NPs varied according to the pH of the initial solution. Moreover, while the size decreased to 11.32 nm with an increase up to 11.66 of the pH value, the size increased rapidly to 39.25 nm with an increase to 12.69. The pH increase up to 11.66 dominantly promoted generation of electrons and increased the amount of initial nucleation in the solution, finally inducing the reduced-size of the Sn particles. However, the additional increase of pH dominantly induced a decrease of PVP by neutralization, which resulted in acceleration of the agglomeration by collisions between particles.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.7
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• pp.424-433
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• 2003

Evolutionary design related to the optimal design of Polynomial Neural Networks (PNNs) structure for model identification of complex and nonlinear system is studied in this paper. The PNN structure is consisted of layers and nodes like conventional neural networks but is not fixed and can be changable according to the system environments. three types of polynomials such as linear, quadratic, and modified quadratic is used in each node that is connected with various kinds of multi-variable inputs. Inputs and order of polynomials in each node are very important element for the performance of model. In most cases these factors are decided by the background information and trial and error of designer. For the high reliability and good performance of the PNN, the factors must be decided according to a logical and systematic way. In the paper evolutionary algorithm is applied to choose the optimal input variables and order. Evolutionary (genetic) algorithm is a random search optimization technique. The evolved PNN with optimally chosen input variables and order is not fixed in advance but becomes fully optimized automatically during the identification process. Gas furnace and pH neutralization processes are used in conventional PNN version are modeled. It shows that the designed PNN architecture with evolutionary structure optimization can produce the model with higher accuracy than previous PNN and other works.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.424-424
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• 2003

Evolutionary design related to the optimal design of Polynomial Neural Networks (PNNs) structure for model identification of complex and nonlinear system is studied in this paper. The PNN structure is consisted of layers and nodes like conventional neural networks but is not fixed and can be changable according to the system environments. three types of polynomials such as linear, quadratic, and modified quadratic is used in each node that is connected with various kinds of multi-variable inputs. Inputs and order of polynomials in each node are very important element for the performance of model. In most cases these factors are decided by the background information and trial and error of designer. For the high reliability and good performance of the PNN, the factors must be decided according to a logical and systematic way. In the paper evolutionary algorithm is applied to choose the optimal input variables and order. Evolutionary (genetic) algorithm is a random search optimization technique. The evolved PNN with optimally chosen input variables and order is not fixed in advance but becomes fully optimized automatically during the identification process. Gas furnace and pH neutralization processes are used in conventional PNN version are modeled. It shows that the designed PNN architecture with evolutionary structure optimization can produce the model with higher accuracy than previous PNN and other works.

• Clean Technology
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• v.3 no.2
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• pp.74-86
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• 1997

Recently the treatment of industrial wastes by membrane processes has drawn much attention due to increasing demands for clean technology. In the process investigated in this study, metal species in the acidic wastes are precipitated as metal hydroxide forms in a neutralization tank, and acid and base solutions are regenerated by water-splitting electrodialysis(WSED) to be reused in the process. Material balances of the processes for treating pickle liquor and mixed wastewater were calculated to explain conceptual design of the process. Experiments for neutralization precipitation with KOH and NaOH for mixed wastewater were carried out to precipitate metal hydroxide and to recover salt solution as supernatant. Also WSED of the salt solutions producing acid and base was tested in 2 or 3 compartment stacks using KCl and NaCl to investigate the effects of stack configurations on the WSED performance.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.2
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• pp.130-135
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• 2000

A two parameter model of a single fictitious weak acid with unknown dissociation constant has been successfully applied to design a neutralization system for many multi-component acid streams. But there are some processes for which above two parameter model is not satisfactory due to poor approxmation of the nonlinearity of pH process. Here, for etter control of wide class of multi-component acid streams, a three parameter model of a strong acid and a weak acid with unknown dissociation constant is proposed. The model approximates effectively three types of largest gain variation nonlinearities. Based on this model a nonlinear pH control system is designed. Parameters can eeasily estimated since their combinations appear linearly in the model equations and nonlinear adaptive control system may also be constructed just as with the two parameter model.

• Textile Coloration and Finishing
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• v.5 no.1
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• pp.33-39
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• 1993

This study was to examine the anti-bacteria effect of chrome-tanned garment leathers by various processes to article from hide. Anti-bacterial test by halo test and shake flask method, and pH value measurment are carried out in this study. The results can be obtained as follows: 1. In the soaking process of chrome-tanned garment leathers, it needs more effective anti-bacterial treatment. 2. pH value of samples by various processes has affected to anti-bacteria effect. 3. Chrome used by the tanning and the neutralization process have been found to be the anti-bacteria activity. 4. The dyeing, the fatliquoring and the finishing process has required anti bacteria treatment.

• Resources Recycling
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• v.12 no.2
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• pp.3-10
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• 2003

Copper oxychloride used as an agricultural fungicide has been recovered from copper-containing waste etchant by the neutralization with alkali hydroxides. Large amount of copper-containing waste etchant is generated from Printed Circuit Board industry. In an environmental and economic point of view, retrieve of the valuable natural resource from the waste is important. Recycling process of copper oxychloride from the waste etchant is discovered through the our study. In the range of reaction temp. 2$0^{\circ}C$-4$0^{\circ}C$, pH 5-7, pure copper oxychloride was able to prepare and the yield of copper oxychloride was higher than 95%. Physical properties of the sample have been characterized using SEM, XRD, TGA, ICP and Atomic absorption spectroscopy.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.673-680
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• 1997

NaOH, $Na_2CO_3, CaO, Ca(OH)_2$ and $CaCO_3$ are widely used counteractives for neoutralizing the waste sulphuric acid produced during the metal surface treatment process and/or the metal refining process. To reduce the tremendous expenses for the neutralization treatment of the waste sulphuric acid, the sludge from calcination plant and the stainless refining dust in POSCO (Pohang Iron ＆ Steel co. Ltd.) was utilized. For the sludge, it will be effective to use calcined and then hydrated sludge in strong acid region (pH<2) and to use the sludge itself in weak acid region (pH>2), The gypsum, the by-product of this treatment, was tested to fit the industrial standard of gypsum, so it is expected that it will solve the lack of gypsum supply. For the stainless refining dust, the phase and the morphology of produced gypsum from waste suiphuric acid neutralization was compared with those from pure sulphuric acid. Because of high reactivity and reaction temperature, $CaSO_4$ non-hydrate was obtained in pure sulphuric acid. But $CaSO_4$ dihydrate was obtained in waste sulphuric acid. It is also judged to be a good material for a counteractive of the waste sulphuric acid.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.258-263
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• 2018

This study attempted to utilize ultrafine precipitated calcium carbonate for fluoride removal from the wastewater of electronics industries. An average particle size of the calcium carbonate was $0.96{\mu}m$, and pH of the aqueous slurry was 10 with 70% in mass. The suspension solution showed approximately 2 mL/hr of the sedimentation rate. The present calcium carbonate solution could be comparable to the conventional aqueous calcium source, $Ca(OH)_2$, for the neutralization and removal of fluoride ions. Depending on the amount of an additional alkali source, less amounts of test Ca-source slurries were required to reach the solution pH of 7.0 than that of using the aqueous calcium hydroxide. It was also found from XRD analysis that more calcium fluoride precipitates were formed by the addition of calcium carbonate solution rather than that of calcium hydroxide. In addition, Minteq equilibrium modelling estimated various ion complexes of fluoride and calcium in this process.