α-Mangostin is a major active compound of mangosteen ( L.) pericarp extract (MPE) that has potent... more α-Mangostin is a major active compound of mangosteen ( L.) pericarp extract (MPE) that has potent antioxidant activity. Unfortunately, its poor aqueous solubility limits its therapeutic application. Purpose: This paper reports a promising approach to improve the clinical use of this substance through electrospinning technique. Polyvinylpyrrolidone (PVP) was explored as a hydrophilic matrix to carry α-mangostin in MPE. Physicochemical properties of MPE:PVP nanofibers with various extract-to-polymer ratios were studied, including morphology, size, crystallinity, chemical interaction, and thermal behavior. Antioxidant activity and the release of α-mangostin, as the chemical marker of MPE, from the resulting fibers were investigated. It was obtained that the MPE:PVP nanofiber mats were flat, bead-free, and in a size range of 387-586 nm. Peak shifts in Fourier-transform infrared spectra of PVP in the presence of MPE suggested hydrogen bond formation between MPE and PVP. The differential ...
A home-made and easy to use I-V meter, which consists of a programmable voltage source, a subnano... more A home-made and easy to use I-V meter, which consists of a programmable voltage source, a subnano-amperemeter, a test fixture where a device under test is put on, and an RS232 interface, has been developed. The I-V meter can be a tool in the laboratory to strengthen concepts delivered in lectures. In addition, the I-V meter can also make students
Abstract Cerium-doped yttrium aluminum garnet (YAG: Ce 3+; Y 3-x Al 5 O 12: Ce x 3+) phosphor nan... more Abstract Cerium-doped yttrium aluminum garnet (YAG: Ce 3+; Y 3-x Al 5 O 12: Ce x 3+) phosphor nanofibers were successfully prepared using an electrospinning method followed by a heating process. Aluminum nitrate nonahydrate, yttrium nitrate hexahydrate, and cerium nitrate hexahydrate dissolved in dimethylformadide, poly (vinyl pyrrolidone), and ethanol comprised the precursor. The precursor was electrospun under atmospheric conditions to obtain the as-prepared fibers, which consisted of salts and the polymer composite. The as- ...
A constant-current electrospinning system has been successfully developed to produce high quality... more A constant-current electrospinning system has been successfully developed to produce high quality nanofibers. In order to keep at a certain value of the electric current, a proportional-integral-derivative (PID) control action was employed, in which the PID parameters were manually tuned. The desired value of electric current was quickly achieved and no overshoot was observed in the system output. The restoration of the electric current due to a disturbance occurred rapidly. Poly (vinyl pyrrolidone)(PVP) nanofibers have been ...
2013 International Conference on Computer, Control, Informatics and Its Applications (IC3INA), 2013
ABSTRACT A linear deformation transducer (LDT), which will be applied to triaxial tests for deter... more ABSTRACT A linear deformation transducer (LDT), which will be applied to triaxial tests for determining deformation behavior of soils, was designed. It, which is made from a thin and flexible steel strip and a strain gage (KFG-5-120-C1-16L1M2R) bonded on the strip using an adhesive, was characterized systematically. Soil deformation was simulated by applying a certain force to the steel strip. The deformed steel strip was converted into a resistance by the strain gage. A full Wheatstone bridge was used to change the resistance into a small analog voltage. The small analog voltage was then amplified by an instrumentation amplifier. This analog voltage was finally processed by a digital data acquisition system consisting of a 12-bit analog to digital converter (ADC) and a microcontroller. It was found that the Wheatstone bridge output voltage obtained by applying a positive change in deformation (the present deformation is bigger than the previous one) is the same as that achieved by its negative change. When an input voltage was supplied to the bridge, the strain gage resistance reduces slightly with the maximum reduction about 1 ohm, from its static resistance of 119.6±0.4 ohm, depending on the force applied to the steel strip and the input voltage supplied to the bridge. For achieving the maximum deformation of 15 mm, the instrumentation amplifier used the supply voltage of 12 V and the gain resistor of 240±1% to get an amplification or gain of 204.8.
ABSTRACT This paper reports the systematic investigation of ion-induced nucleation rate measureme... more ABSTRACT This paper reports the systematic investigation of ion-induced nucleation rate measurement in a SO2/H2O/N2 gas mixture, employing soft X-ray at different pressure and temperature levels. Experiments were conducted using a modified continuous flow gas-generation system employing a soft X-ray ionizer and a particle counter, with an improved integrated online temperature, pressure and a relative humidity (RH) control system. Nucleation rates were measured as a function of SO2 concentration at different levels of RH, pressure (600–970 hPa) and temperature (5–25 °C). The results show that the nucleation rate dependence on SO2 concentration followed a power law, and the slope varied slightly in a range from 1 to 1.26 at different RH levels (15–60%). A positive pressure effect was generally found and a power law was followed with varied scaling for different SO2 concentrations. The trend of an increase in nucleation rate with temperature was consistent with observations in homogenous nucleation experiments, and with the behavior predicted by classical binary nucleation theory. These experimental results will be useful to explain the contribution of ion-induced nucleation in different locations and atmospheric conditions.
BCNO phosphor nanofibers, composed of polycrystalline-BCN and B2O3 crystal, were prepared by elec... more BCNO phosphor nanofibers, composed of polycrystalline-BCN and B2O3 crystal, were prepared by electrospinning followed by calcination at 700 C. These showed intense green and yellow emissions under UV-light irradiation that could be seen by the naked eye. The prepared nanofibers were uniform, non-agglomerate, thermally resistant, and had a good atomic distribution.
New red-emitting phosphors have been produced and studied by investigating the effects of various... more New red-emitting phosphors have been produced and studied by investigating the effects of various additives such as europium (Eu), aluminum (Al), and calcium (Ca) on the photoluminescence performance of boron oxide-based phosphors. When both Eu and Ca ions were added, Ca3B2O6: Eu phosphors could be synthesized via a straightforward process using a liquid precursor. The photoluminescent spectra of Ca3B2O6: Eu phosphors exhibited a red emission at 611nm under 254nm excitation, and the internal quantum ...
Abstract Kemajuan mutakhir dalam bidang pemintalan elektrik telah direview sekilas dengan fokus p... more Abstract Kemajuan mutakhir dalam bidang pemintalan elektrik telah direview sekilas dengan fokus pada riset yang telah dilakukan oleh kelompok kami. Bagian pertama memperkenalkan prinsip dasar pemintalan elektrik. Kemudian, pemodelan dan simulasi proses pemintalan elektrik dijelaskan di bagian kedua.
α-Mangostin is a major active compound of mangosteen ( L.) pericarp extract (MPE) that has potent... more α-Mangostin is a major active compound of mangosteen ( L.) pericarp extract (MPE) that has potent antioxidant activity. Unfortunately, its poor aqueous solubility limits its therapeutic application. Purpose: This paper reports a promising approach to improve the clinical use of this substance through electrospinning technique. Polyvinylpyrrolidone (PVP) was explored as a hydrophilic matrix to carry α-mangostin in MPE. Physicochemical properties of MPE:PVP nanofibers with various extract-to-polymer ratios were studied, including morphology, size, crystallinity, chemical interaction, and thermal behavior. Antioxidant activity and the release of α-mangostin, as the chemical marker of MPE, from the resulting fibers were investigated. It was obtained that the MPE:PVP nanofiber mats were flat, bead-free, and in a size range of 387-586 nm. Peak shifts in Fourier-transform infrared spectra of PVP in the presence of MPE suggested hydrogen bond formation between MPE and PVP. The differential ...
A home-made and easy to use I-V meter, which consists of a programmable voltage source, a subnano... more A home-made and easy to use I-V meter, which consists of a programmable voltage source, a subnano-amperemeter, a test fixture where a device under test is put on, and an RS232 interface, has been developed. The I-V meter can be a tool in the laboratory to strengthen concepts delivered in lectures. In addition, the I-V meter can also make students
Abstract Cerium-doped yttrium aluminum garnet (YAG: Ce 3+; Y 3-x Al 5 O 12: Ce x 3+) phosphor nan... more Abstract Cerium-doped yttrium aluminum garnet (YAG: Ce 3+; Y 3-x Al 5 O 12: Ce x 3+) phosphor nanofibers were successfully prepared using an electrospinning method followed by a heating process. Aluminum nitrate nonahydrate, yttrium nitrate hexahydrate, and cerium nitrate hexahydrate dissolved in dimethylformadide, poly (vinyl pyrrolidone), and ethanol comprised the precursor. The precursor was electrospun under atmospheric conditions to obtain the as-prepared fibers, which consisted of salts and the polymer composite. The as- ...
A constant-current electrospinning system has been successfully developed to produce high quality... more A constant-current electrospinning system has been successfully developed to produce high quality nanofibers. In order to keep at a certain value of the electric current, a proportional-integral-derivative (PID) control action was employed, in which the PID parameters were manually tuned. The desired value of electric current was quickly achieved and no overshoot was observed in the system output. The restoration of the electric current due to a disturbance occurred rapidly. Poly (vinyl pyrrolidone)(PVP) nanofibers have been ...
2013 International Conference on Computer, Control, Informatics and Its Applications (IC3INA), 2013
ABSTRACT A linear deformation transducer (LDT), which will be applied to triaxial tests for deter... more ABSTRACT A linear deformation transducer (LDT), which will be applied to triaxial tests for determining deformation behavior of soils, was designed. It, which is made from a thin and flexible steel strip and a strain gage (KFG-5-120-C1-16L1M2R) bonded on the strip using an adhesive, was characterized systematically. Soil deformation was simulated by applying a certain force to the steel strip. The deformed steel strip was converted into a resistance by the strain gage. A full Wheatstone bridge was used to change the resistance into a small analog voltage. The small analog voltage was then amplified by an instrumentation amplifier. This analog voltage was finally processed by a digital data acquisition system consisting of a 12-bit analog to digital converter (ADC) and a microcontroller. It was found that the Wheatstone bridge output voltage obtained by applying a positive change in deformation (the present deformation is bigger than the previous one) is the same as that achieved by its negative change. When an input voltage was supplied to the bridge, the strain gage resistance reduces slightly with the maximum reduction about 1 ohm, from its static resistance of 119.6±0.4 ohm, depending on the force applied to the steel strip and the input voltage supplied to the bridge. For achieving the maximum deformation of 15 mm, the instrumentation amplifier used the supply voltage of 12 V and the gain resistor of 240±1% to get an amplification or gain of 204.8.
ABSTRACT This paper reports the systematic investigation of ion-induced nucleation rate measureme... more ABSTRACT This paper reports the systematic investigation of ion-induced nucleation rate measurement in a SO2/H2O/N2 gas mixture, employing soft X-ray at different pressure and temperature levels. Experiments were conducted using a modified continuous flow gas-generation system employing a soft X-ray ionizer and a particle counter, with an improved integrated online temperature, pressure and a relative humidity (RH) control system. Nucleation rates were measured as a function of SO2 concentration at different levels of RH, pressure (600–970 hPa) and temperature (5–25 °C). The results show that the nucleation rate dependence on SO2 concentration followed a power law, and the slope varied slightly in a range from 1 to 1.26 at different RH levels (15–60%). A positive pressure effect was generally found and a power law was followed with varied scaling for different SO2 concentrations. The trend of an increase in nucleation rate with temperature was consistent with observations in homogenous nucleation experiments, and with the behavior predicted by classical binary nucleation theory. These experimental results will be useful to explain the contribution of ion-induced nucleation in different locations and atmospheric conditions.
BCNO phosphor nanofibers, composed of polycrystalline-BCN and B2O3 crystal, were prepared by elec... more BCNO phosphor nanofibers, composed of polycrystalline-BCN and B2O3 crystal, were prepared by electrospinning followed by calcination at 700 C. These showed intense green and yellow emissions under UV-light irradiation that could be seen by the naked eye. The prepared nanofibers were uniform, non-agglomerate, thermally resistant, and had a good atomic distribution.
New red-emitting phosphors have been produced and studied by investigating the effects of various... more New red-emitting phosphors have been produced and studied by investigating the effects of various additives such as europium (Eu), aluminum (Al), and calcium (Ca) on the photoluminescence performance of boron oxide-based phosphors. When both Eu and Ca ions were added, Ca3B2O6: Eu phosphors could be synthesized via a straightforward process using a liquid precursor. The photoluminescent spectra of Ca3B2O6: Eu phosphors exhibited a red emission at 611nm under 254nm excitation, and the internal quantum ...
Abstract Kemajuan mutakhir dalam bidang pemintalan elektrik telah direview sekilas dengan fokus p... more Abstract Kemajuan mutakhir dalam bidang pemintalan elektrik telah direview sekilas dengan fokus pada riset yang telah dilakukan oleh kelompok kami. Bagian pertama memperkenalkan prinsip dasar pemintalan elektrik. Kemudian, pemodelan dan simulasi proses pemintalan elektrik dijelaskan di bagian kedua.
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