• Title/Summary/Keyword: Thickness

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A Model for Detection and Refinement of Fixed Bending Regions for Improving the Degree of Thickness Uniformity in Rolled Film Manufacturing (롤 형상 필름 생산에서 두께평활도 개선을 위한 고정굴곡부 발현 모형 및 개선 모델)

  • Bae, Jae-Ho
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.38 no.3
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    • pp.21-28
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    • 2015
  • As film products are increasingly used in a wide range of areas, from producing traditional flexible packaging to high-tech electronic products, a higher level of quality is demanded. Most film products are made in the form of rolled finished goods, therefore, various quality issues related to their shape characteristics must be addressed. The thickness of the film products is one of the most common and important critical-to-quality attributes (CTQs). Particularly, the degree of thickness uniformity is more important than other thickness parameters, because it will be potential causes of many secondary thickness-related quality problems, such as wrinkles or faulty windings. To control the degree of thickness uniformity, the fixed bending region is oneof the most important CTQs to manage. Fixed bending regions are special points in the transverse direction of a rolled product with consistent minute variations of the thickness gap. This paper describes the measurement and analysis of thickness uniformity data, which were performed in a real manufacturing field of biaxial oriented polypropylene (BOPP) film. In previous researches, quality function deployment (QFD) or fault tree analysis were used to find the most critical process attributes out to controlthe CTQ of thickness uniformity. Whereas, this paper uses traditional control charts to find the most critical process attributes out in this problem. In addition, the selection of one of the major critical process attributes (CTPs) that is expected to affect the CTQ of thickness uniformity is also described. The selected critical-to-process attributes are the controlled temperatures along the transverse direction. A dramatic improvement in thickness uniformity was observed when the selected CTPs were controlled.

Correlation analysis of periodontal tissue dimensions in the esthetic zone using a non-invasive digital method

  • Kim, Yun-Jeong;Park, Ji-Man;Cho, Hyun-Jae;Ku, Young
    • Journal of Periodontal and Implant Science
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    • v.51 no.2
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    • pp.88-99
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    • 2021
  • Purpose: Direct intraoral scanning and superimposing methods have recently been applied to measure the dimensions of periodontal tissues. The aim of this study was to analyze various correlations between labial gingival thickness and underlying alveolar bone thickness, as well as clinical parameters among 3 tooth types (central incisors, lateral incisors, and canines) using a digital method. Methods: In 20 periodontally healthy subjects, cone-beam computed tomography images and intraoral scanned files were obtained. Measurements of labial alveolar bone and gingival thickness at the central incisors, lateral incisors, and canines were performed at points 0-5 mm from the alveolar crest on the superimposed images. Clinical parameters including the crown width/crown length ratio, keratinized gingival width, gingival scallop, and transparency of the periodontal probe through the gingival sulcus were examined. Results: Gingival thickness at the alveolar crest level was positively correlated with the thickness of the alveolar bone plate (P<0.05). The central incisors revealed a strong correlation between labial alveolar bone thickness at 1 and 2 mm, respectively, inferior to the alveolar crest and the thickness of the gingiva at the alveolar crest line (G0), whereas G0 and labial bone thickness at every level were positively correlated in the lateral incisors and canines. No significant correlations were found between clinical parameters and hard or soft tissue thickness. Conclusions: Gingival thickness at the alveolar crest level revealed a positive correlation with labial alveolar bone thickness, although this correlation at identical depth levels was not significant. Gingival thickness, at or under the alveolar crest level, was not associated with the clinical parameters of the gingival features, such as the crown form, gingival scallop, or keratinized gingival width.

Body composition and measurement of subcutaneous fat thickness by ultrasonic method (초음파법에 의한 피하지방두께의 측정과 신체조성)

  • 성수광;장수정
    • Journal of the Ergonomics Society of Korea
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    • v.13 no.1
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    • pp.47-58
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    • 1994
  • The purpose of this study was to obtain the basic data for a design for comfort wear. The subjects of this study were 197 women's university stu- dents. The characteristics of their body types and the thickness of subcuta- neous fat at eight body sites were measured. The thickness of subcutaneous fat was measured by both Ultrasonics and with a Skinfold Caliper. The cor- relation between their values and the thickness of subcutaneous fat were compared. The relationship between Rohrer Index and the subject's self- conception of their body was also compared. The results were as follows: 1. The measurement of thickness of subcutaneous fat at triceps and scapula was a little lower, in using Skinfold Caliper method, than Ultrasonics method because of the pressure of the caliper. 2. Correlation between percentage of fat in body and body characteristics was high in order of chest girth > weight > abdomen girth. 3. The thickness of subcutaneous 8 body these sites was high in order of thigh > triceps > scapula > abdomen > suprailiac > chest > calf > forearm. Percentage of body fat has a positive correlation with both average thickness of subcutaneous fat and thickness of subcutaneous fat at triceps. 4. Rohrer Index shows a positive correlation between average thickness of subcutaneous fat and percentage of body fat. 5. About half of subjects of this study thought that they were obese although the data proved otherwise.

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Improvement of an Ultrasonic Transducer for Measuring Both Flow Velocity and Pipe Thickness (유속 및 파이프 두께 측정 겸용 초음파 트랜스듀서 개선)

  • Kim, Ju Wan;Kim, Jin Oh
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.2
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    • pp.148-156
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    • 2016
  • The paper deals with improvement of a piezoelectric ultrasonic transducer for measuring both pipe thickness and flow velocity. The transducer structure is based on the conventional transducers for measuring flow velocity by obliquely transmitting ultrasonic waves to the flow direction. The transducer invented earlier for measuring flow velocity and pipe thickness had an advantage of including only one piezoelectric disc, but for the thickness measurement the ultrasonic wave had to be reflected twice in a wedge material to be transmitted vertically to a pipe, and thus the wave signal was too weak. The transducer has been improved to transmit waves for thickness measurement vertically to a pipe without any prior reflection by electrically connecting two piezoelectric discs, one for flow velocity and the other for pipe thickness measurement. By comparing the measured results of specimen thickness with the improved transducer and conventional transducers, the accuracies of the improved one have been evaluated in the pipe thickness measurements.

A Study on Film Sensitive Effect Influenced by ${\gamma}-ray$(Ir-192) Depending on Thickness of Lead Foil ($\gamma$선(線)(Ir-192)이 연박(鉛箔)두께의 증감(增減)에 따른 필름감도(感度) 효과(效果))

  • Joo, Gwang-Tae
    • Journal of radiological science and technology
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    • v.2 no.1
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    • pp.95-99
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    • 1979
  • When the ${\gamma}-ray$ of average energy 375KeV emitted by Ir-192 is exposed to each film through lead foil with various thickness, the film sensitivity will be different according to the thickness of lead foil and film type. The results on the study, different density and sensitive ratio appeared depending on exposed time and film type, but was made on the following common points. 1. The effect of film sensitivity by the front lead foil showed rapid increase up to the thickness of more or less 0.03mm, and the thicker lead foil was decreased more in the thickness of about $0.05{\sim}0.09mm$. 2. The effect of film sensitivity by the back lead foil was increased up to around of $0.03{\sim}0.08mm$ thickness, the maximum sensitivity was obtained in the thickness of more than $0.03{\sim}0.08mm$ without any change in the above effect. 3. The sensitivity of front lead foil was higher than that of back lead foil in thin lead foil with about 0.127mm thickness, but the sensitivity of back lead foil was higher than that of front lead foil when thickness became thicker.

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The Effects of Age, Gender and Head Size on the Cortical Thickness of Brain (연령, 성별, 머리 크기가 대뇌 피질 두께에 미치는 효과)

  • Park, Yunyoung;Kim, Siekyeong
    • Korean Journal of Biological Psychiatry
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    • v.22 no.3
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    • pp.118-127
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    • 2015
  • Objectives Standardization of head size is essential for the volume study. Cortical thickness analyses are increasingly being used in many fields of neuroscience. However, it is not established whether head size correction should be done for thickness study. Methods Using the Open Access Series of Imaging Studies data, we determined cortical thickness of 316 cognitively normal participants aged 18-94 with FreeSurfer. The association between head size and cortical thickness of whole cortical mantle and in each lobe among age tertile groups was assessed. Estimated total intracranial volume (eTIV) was calculated for determining head size. Results Across all participants, cortical thickness in whole brain except some areas in cingulate and insula decreased with aging. eTIV had positive correlation with the thickness of frontal, parietal, occipital and whole brain areas. However, the age effect was not shown in whole brain of the first tertile group and in cingulate areas of the third tertile group. eTIV had negative correlation with the thickness of cingulate in the third tertile group. Gender effects were shown in some areas in third tertile group, but it would be due to difference of head size. Conclusions These findings suggest that head size standardization might be done especially in older population and in studies of paralimbic areas.

Buckling of axial compressed cylindrical shells with stepwise variable thickness

  • Fan, H.G.;Chen, Z.P.;Feng, W.Z.;Zhou, F.;Shen, X.L.;Cao, G.W.
    • Structural Engineering and Mechanics
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    • v.54 no.1
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    • pp.87-103
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    • 2015
  • This paper focuses on an analytical research on the critical buckling load of cylindrical shells with stepwise variable wall thickness under axial compression. An arctan function is established to describe the thickness variation along the axial direction of this kind of cylindrical shells accurately. By using the methods of separation of variables, small parameter perturbation and Fourier series expansion, analytical formulas of the critical buckling load of cylindrical shells with arbitrary axisymmetric thickness variation under axial compression are derived. The analysis is based on the thin shell theory. Analytic results show that the critical buckling load of the uniform shell with constant thickness obtained from this paper is identical with the classical solution. Two important cases of thickness variation pattern are also investigated with these analytical formulas and the results coincide well with those obtained from other authors. The cylindrical shells with stepwise variable wall thickness, which are widely used in actual engineering, are studied by this method and the analytical formulas of critical buckling load under axial compression are obtained. Furthermore, an example is presented to illustrate the effects of each strake's length and thickness on the critical buckling load.

Effect of Boundary Layer Thickness on the Flow Characteristics around a Rectangular Prism (직사각형 프리즘 주위의 유동특성에 대한 경계층 두께의 영향)

  • Ji, Ho-Seong;Kim, Kyung-Chun
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.306-311
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    • 2001
  • Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers(thick, medium and thin)were generated in the Atmospheric Boundary Layer Wind Tunnel at Pusan National University. The thick boundary layer having 670mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer$(\delta=270mm)$ was the natural turbulent boundary layer at the test section with fully long developing length(18m). The thin boundary layer with 36.5mm thickness was generated by on a smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity and the height of the model was $7.9{\times}10^3$. The mean velocity vector fields and turbulent kinetic energy distribution were measured and compared. The effect of boundary layer thickness is clearly observed not only in the length of separation bubble but also in the reattachment points. The thinner boundary layer thickness, the higher turbulent kinetic energy peak around the model roof. It is strongly recommended that the height ratio between model and approaching boundary layer thickness should be a major parameter.

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Using Reliability Tools to Characterize Wood Strand Thickness of Oriented Strand Board Panels

  • Chastain, J.S.;Young, T.M.;Guess, F.M.;Leo, R.V.
    • International Journal of Reliability and Applications
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    • v.10 no.2
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    • pp.89-99
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    • 2009
  • Oriented Strand Board (OSB) is an important engineered wood product used in housing construction which has a lower environmental impact or "carbon footprint." In this paper, reliability and statistical tools are applied to gain insights on the strand thickness of OSB panels. An OSB panel consists of several hundred wood strands that are resinated and pressed. The variability of OSB strand thickness for six manufacturers in the Eastern United States is examined as a whole, as well as individually. Little research exists on OSB strand thickness across mills even though strand thickness variability has been documented in laboratory experiments to greatly influence the dimensional stability of OSB panels. Our aims are to quantify and characterize strand thickness, plus apply reliability techniques, such as Kaplan-Meier curves, to characterize the probability of strand thickness. We further explore graphically and statistically the thickness of the strands.

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The Effect of Pelvic Floor Muscle Contraction with Image Feedback on Abdominal Muscle Thickness (영상피드백을 적용한 골반저근 수축이 복부 근 두께에 미치는 영향)

  • Kim, Jin-Hee;Kim, Nan-Soo;Jang, Jun-Hyeok
    • Journal of the Korean Society of Physical Medicine
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    • v.7 no.4
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    • pp.533-539
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    • 2012
  • PURPOSE: The purpose of this study was to investigate the effect of pelvic floor muscle contraction with image feedback on Abdominal muscle thickness. METHODS: Twenty three adults participated in this study. Abdominal muscle thickness was measured by ultrasound in three condition(rest, pelvic floor muscle contraction, pelvic floor muscle contraction with image feedback). Subjects was contraction pelvic floor muscle by general method. And ultrasound(convex probe, 3.5MHz) was used to image feedback for selective pelvic floor muscle contraction. One-way ANOVA was used to compare abdominal muscle thickness in three condition. RESULTS: There was no significant difference in external oblique(p=.514) and internal oblique muscle(p=.250) thickness by three condition. There was significant difference in transverse abdominis thickness by three condition (Transverse abdominis thickness was highest while Pelvic floor muscle contraction than pelvic floor muscle contraction with image feedback and rest.)(p=.000). CONCLUSION: This study shows that pelvic floor muscle contraction with image feedback increase the thickness of transverse abdominis lesser than general pelvic floor muscle contraction.