Incidence and associated factors of pediatric post-intensive care syndrome using the VSCAREMD model

Tippayawong Paweethida,Chaiyakulsil Chanapai 대한중환자의학회 2022 Acute and Critical Care Vol.37 No.4

Background: A novel comprehensive model called the VSCAREMD model has been proposed to detect post-intensive care syndrome (PICS) in children. This study aimed to outline the incidence of PICS in children using the VSCAREMD model and to describe the associated factors. Methods: All children ages 1 month to 15 years and admitted to the intensive care unit for at least 48 hours were evaluated using the VSCAREMD model within 1 week of intensive care discharge. The VSCAREMD model is used for evaluating vaccination, sleep, and parental care burden, which includes daily activity and social interaction, rehabilitation requirements, hearing, mood, and development. Abnormal findings were assorted into four domains: physical, cognitive, mental, and social. Descriptive statistics were performed using chi-square, univariate, and multivariate analyses.Results: A total of 78 of 95 children (82.1%) had at least one abnormal domain. Physical, cognitive, mental, and social morbidity were found in 64.2%, 26.3%, 13.7%, and 38.9% of the children, respectively. Prolonged intensive care unit stay greater than 7 days was associated with dysfunction in physical (adjusted odds ratio [aOR], 3.80; 95% confidence interval [CI], 1.31–11.00), cognitive (aOR, 10.11; 95% CI, 3.01–33.89), and social domains (aOR, 5.01; 95% CI, 2.01–12.73). Underlying medical conditions were associated with cognitive (aOR, 13.63; 95% CI, 2.64–70.26) and social morbidity (aOR, 2.81; 95% CI, 1.06–7.47). Conclusions: The incidence of PICS using the VSCAREMD model was substantially high and associated with prolonged intensive care. This model could help evaluate PICS in children.

Ethanolysis of Soybean Oil into Biodiesel : Process Optimization via Central Composite Design

Tippayawong Nakorn,Kongjareon Eaksit,Jompakdee Wasan The Korean Society of Mechanical Engineers 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.10

A process for production of ethyl ester for use as biodiesel has been studied. The sodium hydroxide catalyzed transesterification of soybean oil with ethanol was carried out at different molar ratio of alcohol to oil, reaction temperature and catalyst amount for a constant agitation in two hours of reaction time. Central composite design and response surface methodology were used to determine optimum condition for producing biodiesel. It was found that ethanol to oil ratio and catalyst concentration have a positive influence on ester conversion as well as interaction effects between the three factors considered. An empirical model obtained was able to predict conversion as a function of ethanol to oil molar ratio, reaction temperature and catalyst concentration adequately. Optimum condition for soybean ethyl ester production was found to be moderate ethanol to oil ratio (10.5: 1), mild temperature range ($70^{\circ}C$) and high catalyst concentrations ($1.0\%$wt), with corresponding ester conversion of $93.0\%$.

Ethanolysis of Soybean Oil into Biodiesel : Process Optimization via Central Composite Design

Nakorn Tippayawong,Eaksit Kongjareon,Wasan Jompakdee 대한기계학회 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.10

A process for production of ethyl ester for use as biodiesel has been studied. The sodium hydroxide catalyzed transesterification of soybean oil with ethanol was carried out at different molar ratio of alcohol to oil, reaction temperature and catalyst amount for a constant agitation in two hours of reaction time. Central composite design and response surface methodology were used to determine optimum condition for producing biodiesel. It was found that ethanol to oil ratio and catalyst concentration have a positive influence on ester conversion as well as interaction effects between the three factors considered. An empirical model obtained was able to predict conversion as a function of ethanol to oil molar ratio, reaction temperature and catalyst concentration adequately. Optimum condition for soybean ethyl ester production was found to be moderate ethanol to oil ratio (10.5 : 1), mild temperature range (70℃) and high catalyst concentrations (1.0%wt). with corresponding ester conversion of 93.0%.

Development of a fast-response, high-resolution electrical mobility spectrometer

Panich Intra,Nakorn Tippayawong 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.1

A short electrical mobility spectrometer (EMS) for measuring aerosol size distribution has been developed and presented [Intra and Tippayawong, Korean J. Chem. Eng., 26, 1770, 2009]. In this work, further improvement of the short EMS into a fast-response, and high resolution instrument is presented. This was done by (i) improvement in particle charging, (ii) utilization of faster flow rate, and (iii) adoption of higher number of electrode rings. The so-called “long” EMS consists of three main parts: a particle charger, a long multi-channel size classifier column, and a multichannel electrometer. Performance of the long EMS was preliminarily tested using polydisperse, carbonaceous aerosol particles generated by a diffusion flame. Preliminary test results showed that the long EMS performed comparatively well, and gave faster response and higher resolution than the short EMS. It was a valuable aerosol instrument available for measuring size distribution of aerosol particles.

Approach to Characterization of a Diode Type Corona Charger for Aerosol Size Measurement

Intra Panich,Tippayawong Nakorn The Korean Institute of Electrical Engineers 2005 KIEE International Transactions on Electrophysics Vol.5C No.5

A semi-empirical method to determine the electrostatic characteristics of a diode type corona aerosol charger based on ion current measurement and electrostatic charging theory was presented. Results from mathematical model were in agreement with those from experimental investigation of the charger. Current-voltage characteristics, $N_{i}t$ product and charge distribution against aerosol size were obtained. It was shown that the space charge was significant and must be taken into account at high ion number concentration and low flow rate. Additionally, significant particle loss was evident for particles smaller than 20 nm in diameter where their electrical mobility was high. Increase in charging efficiency may be achieved by introducing surrounding sheath flow and applying AC high voltage. Overall, the approach was found to be useful in characterizing the aerosol charger.

Design and Evaluation of a High Concentration, High Penetration Unipolar Corona Ionizer for Electrostatic Discharge and Aerosol Charging

Intra, Panich,Tippayawong, Nakorn The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.5

The aim of this paper is to design and evaluate a high concentration, high penetration unipolar corona ionizer. The electrostatic characteristics in terms of voltage-current relationships of the present ionizer in the discharge zones for positive and negative coronas were discussed. Using ion current measurement, the concentration and penetration of ions were evaluated at corona voltages across the needle electrodes between 1 and 4 kV, flow rates between 1 and 5 L/min, and an operating pressure of 1 atm. In the discharge zone of the ionizer, the highest ion concentrations were found to be about $1.71{\times}10^{14}$ and $5.09{\times}10^{14}\;ions/m^3$ for positive and negative coronas, respectively. At the outlet of the ionizer, it was found that the highest ion concentration was about $1.95{\times}10^{13}$ and $1.91{\times}10^{13}\;ions/m^3$ for positive and negative coronas, respectively. The highest ion penetration for positive and negative coronas through the ionizer was found to be about 98 % and 33 %, respectively. The $N_it$ product for positive and negative coronas was also found to $1.28{\times}10^{13}$ and $7.43{\times}10^{13}\;ions/m^3s$, respectively. From the findings, this ionizer proved to be particularly useful as an aerosol charger for positive and negative charge before the detector in an electrical aerosol detector.

Comparative Study on Electrical Discharge and Operational Characteristics of Needle and Wire-Cylinder Corona Chargers

Intra, Panich,Tippayawong, Nakorn The Korean Institute of Electrical Engineers 2006 Journal of Electrical Engineering & Technology Vol.1 No.4

The electrical discharge and operational characteristics of needle and wire-cylinder corona charger based on current measurements for positive and negative coronas were evaluated and compared. A semi-empirical method was used to determine the ion concentrations in the charging zone and at the outlet of both chargers. Results from experimental investigation revealed that magnitudes of the charging current from the wire-cylinder charger were approximately 3.5 and 2 times smaller than those from the needle charger for the positive and negative coronas, respectively. The ion number concentrations at the outlet for positive corona of both chargers were higher than fur negative corona at the same voltage. Flow and electric fields in the charging zone of both chargers were also analyzed via numerical computation. Strong electric field strength zone was identified and led to high charging and particle deposition. Effect of particle deposition on the evolution of discharge current was presented. It was shown that ions loss inside the wire-cylinder charger was higher than the needle charger The particle deposited on the corona electrodes and on the grounded cylinder caused a great reduction in charging efficiency of both chargers.

Design and Evaluation of a High Concentration, High Penetration Unipolar Corona Ionizer for Electrostatic Discharge and Aerosol Charging

Panich Intra,Nakorn Tippayawong 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.5

The aim of this paper is to design and evaluate a high concentration, high penetration unipolar corona ionizer. The electrostatic characteristics in terms of voltage-current relationships of the present ionizer in the discharge zones for positive and negative coronas were discussed. Using ion current measurement, the concentration and penetration of ions were evaluated at corona voltages across the needle electrodes between 1 and 4 kV, flow rates between 1 and 5 L/min, and an operating pressure of 1 atm. In the discharge zone of the ionizer, the highest ion concentrations were found to be about 1.71×10<SUP>14</SUP> and 5.09×10<SUP>14</SUP> ions/m³ for positive and negative coronas, respectively. At the outlet of the ionizer, it was found that the highest ion concentration was about 1.95×10<SUP>13</SUP> and 1.91×10<SUP>13</SUP> ions/m³ for positive and negative coronas, respectively. The highest ion penetration for positive and negative coronas through the ionizer was found to be about 98 % and 33 %, respectively. The Nit product for positive and negative coronas was also found to 1.28×10<SUP>13</SUP> and 7.43×10<SUP>13</SUP> ions/m³s, respectively. From the findings, this ionizer proved to be particularly useful as an aerosol charger for positive and negative charge before the detector in an electrical aerosol detector.

Performance evaluation of an electrometer system for ion and aerosol charge measurements

Panich Intra,Nakorn Tippayawong 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.2

An aerosol electrometer system for measuring ion and aerosol charge using electrostatic detection technique was developed and presented. It consists of a size-selective inlet, a particle charger, an ion trap, a Faraday cup,an electrometer, and a data acquisition and processing system. In this system, an aerosol sample first passes through the size-selective inlet to remove particles outside the measurement size range based on their aerodynamic diameter,and then passes through the unipolar corona charger that sets a charge on the particles and enters the ion trap to remove the free ions. After the ion trap, the charged particles then enter the Faraday cup electrometer for measuring ultra low current of about 1 pA induced by ion and aerosol charge collected on the filter in Faraday cup corresponding to the number concentration of ion and aerosol. Signal current is then recorded and processed by a data acquisition system. Finally, the detailed description of the operating principle of the system as well as the preliminary experimental testing results of ion and aerosol charge measurements were also introduced and discussed.

Brownian diffusion effect on nanometer aerosol classification in electrical mobility spectrometer

Panich Intra,Nakorn Tippayawong 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.1

A multi-channel differential mobility analyzer (MCDMA) or aerosol spectrometer is widely used for classifying and measuring nanometer aerosol particles in the size range from 1 nm to 1 µm because of its better time response than a typical differential mobility analyzer. In the present study, the effect of Brownian diffusion on electrical mobility classification and trajectory of nanometer aerosol particles in an electrical mobility spectrometer developed at Chiang Mai University has been analytically investigated. Th Brownian diffusion of particles inside the spectrometer increased with decreasing particle size and flow rates of aerosol and clean sheath air, and with increasing inner electrode voltage, and also decreased with decreasing operating pressure. The particle trajectories considering Brownian diffusion motion inside the spectrometer were found to be broader than those under no Brownian diffusion. Smaller particles were found to have higher degree of broadening of trajectory than the larger particles. Brownian diffusion effect was found to be significant for particles smaller than 10 nm.