• Title/Summary/Keyword: average size

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Correlation to the Physical Properties of Green and Sintered Body of Artificial Lightweight Aggregate with the Pelletizing Variables (펠레타이저 공정변수와 인공경량골재의 성형체와 소성체 물성과의 상관관계)

  • Wie, Young-Min;Lee, Ki-Gang
    • Journal of the Korean Ceramic Society
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    • v.44 no.10
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    • pp.568-573
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    • 2007
  • For the manufacturing lightweight fine aggregate, clay and waste material was formed by pelletizer. The fine aggregate of 1-5 mm diameter was formed by diameter 76 cm pelletizer disc. Pelletization variables were : (1) pelletizer disc angle, (2) speed of revolution of pelletizer, (3) added pelletization time. Green and sintered aggregate were measured specific gravity, absorption rate and average size. The optimum condition were found that the pelletization variables were angle at $70^{\circ}$, speed of revolution of pelletizer at 23.2 rpm, and water/solid ratio at 1/5. At these conditions, it was formed that fine aggregate green whose average size was $2.0{\sim}3.35mm$. Specific gravity and average size are increased with low angle of disc and fast revolution speed of disc. Specific gravity and average size were not distinctly influenced by added pelletization time. Sintered aggregate was distinctly influenced by properties of green.

Preparation of Poly-L-Lactic Acid (PLLA) Microspheres by Solvent-Evaporation Method (용매증발법을 이용한 Poly-L-Lactic Acid (PLLA) 마이크로스피어 제조)

  • Kim, Tae Hyoung;Song, Ki Chang
    • Korean Chemical Engineering Research
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    • v.56 no.4
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    • pp.461-468
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    • 2018
  • Microspheres were prepared by solvent-evaporation method with Poly-L-lactic acid (PLLA) as a starting material, and the effects of preparation variables on microsphere shape and average particle size were investigated. As the concentration of PVA solution increased from 1 to 5 wt%, the average particle size decreased from $370{\mu}m$ to $160{\mu}m$ and then increased to $240{\mu}m$ at 7 wt%. On the other hand, As the addition volume of PVA solution increased from 10 mL to 50 mL, the average particle size decreased from $370{\mu}m$ to $220{\mu}m$. Also, as the stirring speed increased from 500 rpm to 1,500 rpm, the average particle size decreased from $370{\mu}m$ to $110{\mu}m$. When dichloromethane and chloroform were used as organic solvents, respectively, the average particle size did not show any significant difference. However, when dichloromethane was used, voids were observed on the particle surface, but when chloroform was used, smooth spherical particles were obtained.

The Comparison Research on the Wearing Practice and Fitness Evaluation of Children's Clothing for Obese and Average body shape of Late Elementary Schoolgirls (비만 및 표준체형 학령후기 여아의 아동복 착용과 치수적합성 비교 분석)

  • Lim, Ji-Young
    • Fashion & Textile Research Journal
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    • v.11 no.2
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    • pp.278-285
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    • 2009
  • As children's apparel industry expands, there are many researches on purchasing and wearing children's clothing and optimal sizes, but researches on purchasing and wearing children's clothing and the appropriateness of sizes comparing average body shape and obese children are still inadequate. Therefore, in this research Late Elementary Schoolgirls ranging in age from 12 to 13 are categorized into the average or the obese body type, and by comparing and analyzing purchasing and wearing children's clothing and the appropriateness of its sizes between these groups, the problems in the size system of children's apparel are realized and the basic information about designing children's clothing for average body shape and non-average body shape(out-size)children are presented. The survey questions were composed of topics about general personal information, the purchasing practice and wearing practice, the appropriateness of its size when wearing children's clothing and the practice of mending apparel according to the satisfaction level of children's clothing sizes. Because subjects are often too big to wear children's clothing, and in the case of obese children the deviation of a body type is amplified, therefore in buying and wearing children's clothing, they demonstrate different forms of purchasing and wearing characteristics than adults. Considering the practice of increasing obesity in children due to westernized eating habits and decreased physical activities, along with developing programs for improving obesity, the development of an optimal size system in response to various body types will become an important challenge.

A Study on Characteristics of Water Content Changes of Wastewater Sludge Using Direct Current Electricity (직류전기를 이용한 하수슬러지 함수율 변화특성에 관한 연구)

  • Ahn, Jeong-Mo;Song, Ji-Yun;Joo, Jae-Young;Bae, Yun-Sun;Park, Chul-Hwi
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.5
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    • pp.609-615
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    • 2010
  • This study examined the change of water content in sludge using direct current electric equipment for decreasing the amount of sludge. The experiment showed that the average density of solids in the sludge treated by direct current before the centrifugal dewatering process was increased by 47.8%, when compared to those not treated by direct current. From the result of measuring the granularity of the sludge by the direct current treatment, that the average particle size of the sludge that was not exposed to the electric current was 52.36 ${\mu}m$, and more than 90% of the sludge was <94.29 ${\mu}m$ in size. On the other hand, the average particle size of the sludge passed through the direct current was 28.67 ${\mu}m$, and more than 90% of the sludge was 52.46 ${\mu}m$. This means that the average particle size of the sludge treated by the direct current was 45.2% smaller, and the standard deviation of granularity was improved. Because of water that separated from sludge moves to the (+) pole, larger particles become smaller and fine particles combine together, resulting in the equalization of the particle size. On the sludge after the centrifugal dehydrator, the change of the water content by the direct current was measured. The results showed that the average density of the solids was increased by 44.2% compared.

Preparation of Nano-Sized ITO Powder from Waste ITO Target by Spray Pyrolysis Process (폐(廢) ITO 타겟으로부터 분무열분해(噴霧熱分解) 공정(工程)에 의한 ITO 나노 분말(粉末) 제조(製造))

  • Yu, Jae-Keun;Kang, Seong-Gu;Sohn, Jin-Gun
    • Resources Recycling
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    • v.16 no.1 s.75
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    • pp.28-36
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    • 2007
  • Nano-sized ITO powders with the average particle size below 50 nm were synthesized from complex acid solution dissolved the ITO target into hydrochloric acid by a spray pyrolysis process, and the influences of reaction factors as reaction temperature and concentration of raw material solution were investigated. As the reaction temperature increases from 800 to $1000^{\circ}C$, the average particle size of the ITO powder increases from 40 nm to 100 nm, the microstructure gradually becomes solid, individual particles independently appear with the shape of polygon, the particle size distribution becomes increasingly irregular, the XRD peak intensity gradually increases and the specific surface area decreases. As the concentration of the raw material solution increases from 50g/l to 400g/l, the average particle size of ITO powder gradually increases, yet the particle size distribution appears more irregular. When the concentration is at 50 g/l, the average particle size of ITO powder is below 30 nm and the particle size distribution appears comparatively uniform. Nevertheless, when the concentration reaches 400 g/l, which is close to e saturated concentration, the particle size distribution appears extremely irregular, and the particles with the size ranging from 20 nm to 100 nm coexist. Along with the concentration rise, the XRD peak intensity gradually increases, yet the specific surface area decreases.

Preparation of Nano-Sized Indium Oxide Powder by Spray Pyrolysis Process (噴霧熱分解 工程에 의한 인듐 酸化物 나노 粉末 製造)

  • Yu, Jae-Keun;Park, Si-Hyun;Sohn, Jin-Gun
    • Resources Recycling
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    • v.13 no.6
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    • pp.16-25
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    • 2004
  • In this study, nano-sized indium oxide powder with the average particle size below 100 nm is prepared from the indium chloride solution by the spray pyrolysis process. The effects of the concentration of raw material solution, the nozzle tip size and the air pressure on the properties of powder were studied. As the indium concentration of the raw material solution increased from 40 g/l to 350 g/l, the average particle size of the powder gradually increased from 20 nm to 60 nm, yet the particle size distribution appeared more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the nozzle tip size increased from 1 nm to 5 nm, the average particle size of the powder increased from 40 nm to 100 nm, the particle size distribution was much more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the air pressure increased from 0.1 kg/cm$^2$ to 0.5 kg/cm$^2$, the average particle size of the powder varies slightly upto 90~100 nm. As the air pressure increased from 1 kg/cm$^2$ to 3 kg/cm$^2$, the average particle size decreased upto 50~60 nm, the intensity of a XRD peak decreased and the specific surface area increased.

Catch per Unit Effort and Size Composition of Crayfish, Astacus leptodactylus Eschscholtz 1823, in Lake İznik

  • Balik, Ismet;Ozkok, Ergun;Ozkok, Remziye
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.6
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    • pp.884-889
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    • 2002
  • This paper was carried out from 15 June to 24 December in 2000 in Lake İznik of Turkey, to determine catch per unit effort (CPUE) and size composition of crayfish, Astacus leptodactylus Eschscholtz 1823, captured by fyke-nets of local fishermen. The average CPUE of all size groups was found as 1.65 crayfish/fyke-net/night for fishing season in 2000, but 26.4% of which was below the legal minimum size (crayfish<90 mm). The average CPUE of legal-sized (crayfish$\geq$90 mm) crayfish was 1.10 crayfish/fykenet/night. The annual catch of crayfish was estimated as 2990 tonnes. The length and weight compositions of crayfish captured in the fyke-nets have varied between 60 and 130 mm, and 6 and 71 g, respectively. The mean length and weight were found as 95.5 mm and 28.8 g for all size groups and 100.1 mm and 33.0 g for legal-sized individuals.

Behaviors of Rubber Particles, Lead and Zinc in Atmospheric Particulate Classified by Particle Size Range (대기 부유분진중의 고무성분 및 납과 아연의 입도별 거동)

  • 이용근;원정호;김경섭;황규자
    • Journal of Korean Society for Atmospheric Environment
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    • v.2 no.2
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    • pp.60-65
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    • 1986
  • Atmospheric particulates were collected at a site near the front gate of the Yonsei University using nine stages Andersen air sampler and the distribution of seasonal particle size was investigated. Rubber, Pb and Zn contents of the collected particulates in each stage were determined. Particle size distribution of atmospheric particulate, which was made by concentration distribution curve method, was usually divided into two groups, course (particles larger than 1 - 2 $\mu m in diameter$) and fine (particles smaller than 1 - 2 \mu m in diameter$) groups, regardless of sampling period. More than 80 percent of the total rubber contents in atmospheric particulates were larger than $5 \mu m$ in diameter, meaning that most of rubber particles were originated from tire tread. After benzene extraction for 4 hrs, the extracts were analyzed by Curie-point pyrolysis gas chromatography for rubber content. Pb and Zn contents were determined by atomic absorption spectroscopy. The annual average concentration of rubber particles was $4.2 \mu g/m^3$, which corresponded to 2.2% of the annual average total suspended particulates. Average concentration of styrene brtadiene rubber was about five times that of natural rubber. Annual average concentrations of Pb and Zn were $1.2 \mu g/m^3 and 0.4 \mu g/m^3$ respectively, which corresponded to about 0.7% and 0.2% of the annual average total suspended particulates.

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A Study on Kernel Size Variations in 1D Convolutional Layer for Single-Frame supervised Temporal Action Localization (단일 프레임 지도 시간적 행동 지역화에서 1D 합성곱 층의 커널 사이즈 변화 연구)

  • Hyejeong Jo;Huiwon Gwon;Sunhee Jo;Chanho Jung
    • Journal of IKEEE
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    • v.28 no.2
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    • pp.199-203
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    • 2024
  • In this paper, we propose variations in the kernel size of 1D convolutional layers for single-frame supervised temporal action localization. Building upon the existing method, which utilizes two 1D convolutional layers with kernel sizes of 3 and 1, we introduce an approach that adjusts the kernel sizes of each 1D convolutional layer. To validate the efficiency of our proposed approach, we conducted comparative experiments using the THUMOS'14 dataset. Additionally, we use overall video classification accuracy, mAP (mean Average Precision), and Average mAP as performance metrics for evaluation. According to the experimental results, our proposed approach demonstrates higher accuracy in terms of mAP and Average mAP compared to the existing method. The method with variations in kernel size of 7 and 1 further demonstrates an 8.0% improvement in overall video classification accuracy.

Reclamation of Waste Lubricating Oil Using Ceramic Micro/Ultrafiltration Composite Membrances (세라믹 정밀/한외여과 복합막을 이용한 폐윤활유 정제)

  • 김계태;현상훈
    • Journal of the Korean Ceramic Society
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    • v.37 no.5
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    • pp.403-409
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    • 2000
  • The permeation characteristics and reclamation efficiency of waste lubricating oil were studied as a function of the types of ceramic composite membranes and the membrane separation process variables. The oil permeability of the TiO2 composite membrane(pore size 0.015 $\mu\textrm{m}$) was directly proportional to the crossflow velocity(0.22∼0.9 m/s) and temperature(150$^{\circ}C$∼200$^{\circ}C$). In the batch concentration process, as the concentration factor increased, both the permeability and the ash content of the permeate decreased. The average ash contents of the total permeate through the A6 alumina membrane(average pore size 0.8$\mu\textrm{m}$), Z1/A6 and Z1/A4(pore size 0.23$\mu\textrm{m}$)/A7(pore size 6$\mu\textrm{m}$) zirconia composite membrances(average pore size 0.07$\mu\textrm{m}$) were about 0.063 wt%, 0.045wt% and 0.08wt% in the region of 1∼2 concentration factor, respectively. The ash content of the mixed permeate through the A6 alumina and zirconia composite membrane was about 0.06 wt% and it can be also reduced to 0.06 wt% in the Z1/A6 membrane and below 0.003 wt% in the TiO2/Z1/A6 membrane. It was concluded that the treated oil obtained from the multi-step membrane separation process could be used as reclaimed lubricating oil as well as reclained fuel oil.

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