• Title, Summary, Keyword: pulverization

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Characterization of pulverized normal and waxy rice starches (멥쌀과 찹쌀전분의 초미립분쇄 후 특성변화연구)

  • Han, Jung-Ah
    • Korean journal of food and cookery science
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    • v.29 no.6
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    • pp.833-839
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    • 2013
  • Separated normal and waxy rice starches were pulverized, and the physicochemical and digestive properties of the starches were determined. The size of both starch granules significantly decreased (less than $8{\mu}m$) after pulverization. For pasting properties, significant decreases of peak and setback viscosity were observed in both of pulverized starches than in native ones. The lower pasting temperature as well as increased solubility and water binding capacity of pulverized starches imply molecular degradation of starch by pulverization. For thermal properties, onset temperature and melting enthalpy significantly decreased after pulverization, especially in normal rice starch, however there was no difference in amylose-lipid complex before andafter pulverization. The slowly digestible and resistant starch portion of normal rice starch increased after pulverization, however, in waxy rice starch, the rapidly digestible portion increased.

Changes in Physicochemical Properties of Rice Starch Processed by Ultra-Fine Pulverization

  • Han, Myung-Ryun;Chang, Moon-Jeong;Kim, Myung-Hwan
    • Journal of Applied Biological Chemistry
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    • v.50 no.4
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    • pp.234-238
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    • 2007
  • The effects of ultra-fine pulverization on the physicochemical properties of rice starch (RS) were investigated using a high impact planetary mill. After pulverization, RVA characteristics, peak viscosity, break down, and set back values of RS decreased from 274.75 to 9.42 RVU, 214.46 to 6.17 RVU, and 87.80 to 17.00 RVU, respectively. The pasting properties also changed significantly. X-Ray diffractogram revealed RS had four A-type peaks, which disappeared after pulverization. The peak temperature and gelatinization enthalpy of RS using differential scanning calorimetry (DSC) were 13.99 J/g at $75.14^{\circ}C$, whereas the pulverized RS (PRS) had two peaks, 0.13 J/g at $63.88^{\circ}C$ and 1.23 J/g at $101.24^{\circ}C$. DSC measurement showed the retrogradation degree of PRS was lower than that of RS after storage at 4 and $25^{\circ}C$. The enzymatic (${\alpha}$-amylase) digestibilities of RS and PRS were 72.7 and 77.3%, respectively.

Effects of soaking on a lime stabilized clay and implications for pavement design

  • Bozbey, Ilknur;Kelesoglu, M. Kubilay;Oztoprak, Sadik;Komut, Muhammet;Comez, Senol;Ozturk, Tugba;Mert, Aykan;Ocal, Kivilcim
    • Geomechanics and Engineering
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    • v.24 no.2
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    • pp.115-127
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    • 2021
  • This paper investigates the effects of soaking on a lime stabilized high plasticity clay and evaluates the implications for pavement design. In this context, the soil was stabilized by 4%, 6% and 9% hydrated lime. The soil was pulverized in two different gradations so that representative field gradations could be simulated. Both soil pulverization levels passed the relevant field gradation criteria. Curing durations were chosen as 7 days, 28 days and 56 days. Two groups of samples were prepared and were tested in unconfined compression test apparatus to measure the strength and secant modulus at failure values. One of the groups was tested immediately after curing. The other group of samples were first cured and then subjected to soaking for ten days before testing. Visual observations were made on the samples during the soaking period. The results showed the superiority of fine soil pulverization over coarse soil pulverization for unsoaked conditions in terms of strength and modulus values. Soaking of the samples affected the unconfined compressive strength and modulus values based on lime content, curing duration and soil pulverization level. In soaked samples, fine soil pulverization resulted in higher strength and modulus values compared to coarse soil pulverization. However, even with fine soil pulverization, effects of soaking on modulus values were more significant. A new term named as "Soaking Influence Factor (SIF)" was defined to compare the reduction in strength and modulus due to soaking. The data was compared with the relevant design guidelines and an attempt was made to include Soaking Influence Factors for strength and modulus (SIFS and SIFM) into pavement design processes. Two equations which correlated secant modulus at failure to unconfined compressive strength were proposed based on the samples subjected to soaking. The results of this study showed that in order to decrease the diverse effects of soaking for lime stabilized soils, soil pulverization level should be kept as fine as possible in the field. Importance of proper drainage precautions in the pavements is highlighted for better performance of the pavements.

PARTICLE SIZE-DEPENDENT PULVERIZATION OF B4C AND GENERATION OF B4C/STS NANOPARTICLES USED FOR NEUTRON ABSORBING COMPOSITES

  • Kim, Jaewoo;Jun, Jiheon;Lee, Min-Ku
    • Nuclear Engineering and Technology
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    • v.46 no.5
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    • pp.675-680
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    • 2014
  • Pulverization of two different sized micro-$B_4C$ particles (${\sim}10{\mu}m$ and ${\sim}150{\mu}m$) was investigated using a STS based high energy ball milling system. Shapes, generation of the impurities, and reduction of the particle size dependent on milling time and initial particle size were investigated using various analytic tools including SEM-EDX, XRD, and ICP-MS. Most of impurity was produced during the early stage of milling, and impurity content became independent on the milling time after the saturation. The degree of particle size reduction was also dependent on the initial $B_4C$ size. It was found that the STS nanoparticles produced from milling is strongly bounded with the $B_4C$ particles forming the $B_4C$/STS composite particles that can be used as a neutron absorbing nanocomposite. Based on the morphological evolution of the milled particles, a schematic pulverization model for the $B_4C$ particles was constructed.

Preparation of Kenyaite/epoxy Nanocomposite from Pulverization of Kenyaite (분쇄된 Kenyaite를 이용한 Kenyaite/epoxy 나노복합체 제조)

  • Joo, Eul-Rea;Jeong, Soon-Yong;Oh, Seong-Geun;Kwon, Oh-Yun
    • Applied Chemistry for Engineering
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    • v.18 no.1
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    • pp.48-53
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    • 2007
  • Pulverization characteristics of H-kenyaite in vibration mill and exfoliation property in epoxy of pulverized H-kenyaite was investigated by using XRD, SEM, TEM. and particle size analyzer. Pulverization was conducted for 0.5~5 h. The particle morphology of sample pulverized for 1 h preserved plate-shape. However, this plate-shape disappeared in the sample pulverized for 3 h. The XRD pattern of sample pulverized for 1 h showed the characteristic peak of H-kenyaite. However, the peak disappeared in samples pulverized above 3 h, indicating severe destruction of H-kenyaite structure. TEM analysis for the kenyaite/epoxy nanocomposites exhibited only gallery expansion of 3~5 nm in non-pulverized sample, but dramatical large expansion of 5~10 nm in the samples pulverized during 1 h. This results confirm that the pulverization of wide plates composed of H-kenyaite particle have largely affect on the formation of an exfoliated kenyaite-polymer nanocomposite.

Investigation of Physical Property Change in Modified Rice Starch by Ultra Fine Pulverization (초미세분쇄를 이용한 쌀 변성전분의 물리적 특성 변화구명)

  • Han, Myung-Ryun;Chang, Moon-Jeong;Kim, Myung-Hwan
    • Applied Biological Chemistry
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    • v.50 no.3
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    • pp.160-166
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    • 2007
  • This study was performed to analyze the molecular structural and physical properties changes of modified rice starch, which particle structure was broken using high impact planetary mill and ultra fine pulverizing techniques. The average diameter and specific surface area of rice starch after pulverization decreased 20% and increased 25%, respectively. Low molecular substances content in rice starch using GPC (gel permeation chromatography) increased from 36.5% to 59.5% after pulverizing of rice starch. Damaged starch contents in rice starch also increased from 16.4% to 99.2% after pulverizing of rice starch. Water holding capacity, solubility and transmittance of rice starch after pulverization increased compared to those of control. Apparent viscosity value of rice starch after pulverization decreased to 7% in control based on $30^{\circ}C$ and 20 RPM conditions.

Investigation of Physical Property Change in Modified Corn Starch by Ultra Fine Pulverization (초미세분쇄를 이용한 옥수수 변성전분의 물리적 특성 변화 구명)

  • Han, Myung Ryun;Kim, Ae Jung;Chang, Moon Jeong;Lee, Soo Jeong;Kim, Hee Sun;Kim, Myung Hwan
    • Food Engineering Progress
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    • v.13 no.4
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    • pp.335-340
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    • 2009
  • This study was performed to analyze changes in the molecular structural and physical properties of modified corn starch, in which particle structure was broken using high impact planetary mill and ultra fine pulverizing techniques. The average diameter and specific surface area of the modditied corn starch after pulverization decreased 50% and increased 567%, respectively. Content of low molecular substances mersured using gel permeation chromatography (GPC) increased from 21.0% to 86.5% after pulverizing corn starch. Damaged starch content also increased from 9.63% to 83.57% after pulverizing corn starch. After pulverization, gel formation capacity corn starch was reduced compared to that of control by structure breakdown.

Effects of post-calcination and mechanical pulverization on the electrochemical properties of nano-sized Li4Ti5O12 for hybrid capacitors

  • Lee, Byung-Gwan;Ahn, Hyo-Jin;Yoon, Jung-Rag
    • Current Applied Physics
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    • v.17 no.2
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    • pp.121-125
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    • 2017
  • Great efforts have been devoted for the synthesis of $Li_4Ti_5O_{12}$ nanoparticles as anode material, because particle size less than 100 nm is the main factor for achieving a high rate capability. In this study, we fabricated nano-sized $Li_4Ti_5O_{12}$ by high-energy milling operated at 3500 rpm, that it was treated afterwards by post-calcination to improve its pulverized crystallinity. Post-calcination at moderate temperature is found to be effective for improving the electrochemical properties of $Li_4Ti_5O_{12}$ prepared by mechanical pulverization. Finally, a 100 nm-sized $Li_4Ti_5O_{12}$ was successfully obtained by optimizing the high-energy milling passing 10 times in chamber and setting post-calcination to $700^{\circ}C$. The specific capacity significantly depended on the crystallinity of $Li_4Ti_5O_{12}$ after treated by the post-calcination. The 100 nm-sized $Li_4Ti_5O_{12}$ showed high-rate capability and good capacity retention of 99.9% after 1500 cycles. It can be explained by the synergistic effect of reduced particle size and improved crystallinity.

A Study on Improvement of Valuable Metals Leaching and Distribution Characteristics on Waste PCBs(Printed Circuit Boards) by Using Pulverization Process (폐 PCBs의 미분쇄 공정 적용에 따른 유가금속 분포 특성 및 금속 침출 향상에 관한 연구)

  • Han, Young-Rip;Choi, Young-Ik
    • Journal of Environmental Science International
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    • v.24 no.2
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    • pp.245-251
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    • 2015
  • The main objective of this study is to recovery valuable metals with metal particle size distributions in waste cell phone PCBs(Printed Circuit Boards) by means of pulverization and nitric acid process. The particle size classifier also was evaluated by specific metal contents. The PCBs were pulverized by a fine pulverizer. The particle sizes were classified by 5 different sizes which were PcS1(0.2 mm below), PcS2(0.20~0.51 mm), PcS3(0.51~1.09 mm), PcS4(1.09~2.00 mm) and PcS5(2.00 mm above). Non-magnetic metals in the grinding particles were separated by a hand magnetic. And then, Cu, Co and Ni were separated by 3M nitric acid. Particle diameter of PCBs were 0.388~0.402 mm after the fine pulverizer. The sorting coefficient were 0.403~0.481. The highest metal content in PcS1. And the bigger particle diameter, the lower the valuable metals exist. The recovery rate of the valuable metals increases in smaller particle diameter with same leaching conditions. For further work, it could improve to recovery of the valuable metals effectively by means of individual treatment, multistage leaching and different leaching solvents.

Physicochemical Property Changes of Sweet Potato Starch by Ultra Fine Pulverization

  • Kim, Hee-Sun;Park, Hye-Young;Han, Gwi-Jung;Kim, Myung-Hwan
    • Food Engineering Progress
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    • v.15 no.2
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    • pp.169-174
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    • 2011
  • This study was performed to analyze the effects of ultra fine pulverization (UFP) on the physicochemical properties of sweet potato starch (SPS). The average diameter and specific surface area of the SPS was decreased from 22.94 to 10.25 $\mu$m and from 0.879 to 1.909 $m^2$ /g throughout UFP, respectively, and the damaged starch content was increased from 13.7 to 99.2%. The pulverized sweet potato starch (PSPS) had higher swelling power, solubility, and transmittance values than the SPS. X-ray diffractograms revealed that the SPS had a C-type pattern, which disappeared in PSPS. The rapid visco analysis (RVA) characteristics, peak viscosity, break down, and set back of SPS ceased to exist in PSPS. According to differential scanning calorimetry (DSC) curves, the peak temperature ($T_p$) and gelatinization enthalpy ($\Delta$E) of SPS were $71.95^{\circ}C$ and 10.40 J/g, respectively, while these remained undetected in PSPS. The enzymatic digestibilities of SPS and PSPS were 61.7 and 84.7%, respectively.