• Clinics in Shoulder and Elbow
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• v.19 no.1
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• pp.15-19
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• 2016

Background: To investigate how many rookie pitchers suffered from injuries while playing in the amateur league without guidelines for prevention of excessive pitching, we analyzed their amateur pitching patterns based on the pitch count, use of breaking balls, and pitches during winter camp. Methods: Forty-one rookie pitchers who graduated from high school or university in 2013 and joined professional baseball teams. Participants were interviewed by a trainer using our questionnaire. Injury inclusion criteria were 1) history of shoulder surgery, 2) history of elbow surgery, 3) shoulder pain requiring treatment, and 4) elbow pain requiring treatment. Results: Mean number of pitches per game and warm-up pitches for practice was 84.5 pitches (range, 15 to 130 pitches) and 16.4 pitches (range, 2 to 210 pitches), respectively. Mean number of pitches during the last year was 906.9 (range, 80 to 2,000). Mean number of maximal pitches was 127 pitches (range, 50 to 210 pitches). Fourteen pitchers had pitched over 150 pitches. Twenty-seven pitchers (65.9%) had pitched in spite of enduring pain. During winter training (mean 1.8 months), mean number of pitches per day was 162.5 pitches, and 20 pitchers (48.8%) had practiced pitching excessively despite the cold weather. Twenty-six rookies (63.4%) had shoulder pain or history of shoulder surgery, and 31 pitchers (75.6%) had elbow pain or history of elbow surgery. Only four participants (9.8%) did not have pain and history of surgery. Conclusions: For young baseball pitchers, guidelines for prevention of excessive pitching and for regulating the winter training program may be needed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.33-42
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• 2015

Pitches contained in thermomechanical pulp negatively influence paper qaulity and pulp and papermaking process. Without controlling TMP pitches suitably, it is hard to make a certain quality of paper. In order to control pitches in TMP, they must be quantitatively recognized by proper tools. One of the most widely used way to detecting TMP pitches is a staining method using a hydrophobic dye such as Sudan IV. Sudan IV could be used with three different protocols including different application of its dissolution, washing, dyeing time, etc. The dyeing protocols were classified into three categories including Stain I, Stain II, and Stain III. In dyeing time, Stain I required more than 24 hours to dye pitches. On the other hand, Stain III could stain TMP pitches with the most brief way. The images of red-stained pitches could be captured by a stereomicroscope with ${\times}35$ and ${\times}45$ magnifications, and then quantitatively analysed measuring their numbers and areas by Carl Zeiss AxioVision (ver. 4.8.2) program. Among three protocols, both Stain I and Stain III were the most ideal methods to detect TMP pitches because they detected more pitches and bigger pitch areas compared to Stain II against the same specimen. In particular, it was recognized that Stain III could be used as the most useful tool to detect TMP pitches accurately within several minutes.

• Journal of the Korean Wood Science and Technology
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• v.33 no.5 s.133
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• pp.57-65
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• 2005

Following our previous reports for finger-jointed woods with various finger profiles studied for the efficient use of small diameter logs and woods containing various defects, twelve types of finger-jointed woods glued with three kinds of adhesives and with two sizes of finger pitches were made with sitka spruce and red pine. The effects of the adhesives and finger pitches on bending creep performances of finger-jointed woods were investigated. The shape of creep curves differed among the used adhesives and finger pitches of finger-jointed woods for both tested species. Their creep curves showed a linear behavior beyond about one hour, and the N values fitted to power law increased with increasing finger pitches. The initial deformation increased with increasing finger pitches, regardless of the tested species and kinds of adhesives, whereas the effect of finger pitches on the creep deformation was not clear. For finger-jointed woods glued with polyvinyl acetate (PVAc) resin, creep failure occurred in 106 hours after the load was applied. And the difference of the creep compliance between finger-jointed woods glued with resorcinol-phenol formaldehyde (RPF) resin and aqueous vinyl urethane (AVU) resin was small. The ratios for creep performances of finger-jointed woods glued with RPF resin and AVU resin versus solid wood were higher in creep deformation than initial deformation for both species, and the difference between both adhesives was not found. The relative creep decreased with increasing finger pitches, and the marked differences was not found between RPF resin and AVU resin.

• Korean Journal of Materials Research
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• v.23 no.5
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• pp.276-280
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• 2013

Coal tar is the primary feedstock of premium graphitizable carbon precursor. Coal tars are residues formed as byproducts of thermal treatments of coal. Coal tar pitches were prepared through two different heat treatment schedules and their properties were characterized. One was prepared with argon and oxidation treatment with oxygen; the other was prepared with oxygen treatment at low temperature and then argon treatment at high temperature; both used coal tar to prepare coal tar pitches. To modulate the properties, different heat treatment temperatures ($300{\sim}400^{\circ}C$) were used for the coal tar pitches. The prepared coal tar pitches were investigated to determine several properties, such as softening point, C/H ratio, coke yield, and aromaticity index. The coal tar pitches were subject to considerable changes in chemical composition that arose due to polymerization after heat treatment. Coal tar pitch showed considerable increases in softening point, C/H ratio, coke yields, and aromaticity index compared to those characteristics for coal tar. The contents of gamma resin, which consists of low molecular weight compounds in the pitches and is insoluble in toluene, showed that the degree of polymerization in the pitches was proportional to C/H ratio. Using an oxidizing atmosphere like air to prepare the pitches from coal tar was an effective way to increase the aromaticity index at relatively low temperature.

• The Journal of the Acoustical Society of Korea
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• v.10 no.1
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• pp.37-46
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• 1991

The pitch estimation algorithms witch have proposed until now are difficult to detect wide range pitches regardless of age or sex. A little deviation are observed with reference to the center pitch in the distribution diagram of pitches, since pitches are characterized by a physical limitation of the coarticulation mechanism. If the center pitches are refered to the accurate pitch extraction procedure, the algorithms will be not only simplified in procedure but also improved in accuracy. In this paper, we proposed an algorithm that the center pitches are accurately detected by using the spectrum leakage phenomenon for the noise speech signals.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.406-412
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• 2015

Unidirectional carbon/carbon (C/C) composites were manufactured using phenolic resins as a precursor of the carbonized matrix throughout a one-step manufacturing process. Also, molybdenum oxide ($MoO_3$) and binder pitches were impregnated with phenolic resins to improve the bulk density and mechanical property of the C/C composites. In this study, the influence of $MoO_3$ and binder pitches on mechanical properties of the C/C composites were investigated by measuring flexural strength (${\sigma}_f$) and interlaminar shear strength (ILSS). The results show that the enhancement of interfacial adhesions between the fibers and matrix resins of the C/C composites with $MoO_3$ and binder pitches which led to the improvement of mechanical properties of the C/C composites. This indicates that the presence of $MoO_3$ and binder pitches in C/C composites can develop the graphite structure and increase the bulk density.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.4
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• pp.421-430
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• 2016

To prepare mesophase pitches through low energy process, pyrolysis fuel oil with $AlCl_3$ has been modified using two-step heat treatment which is heat-treated at $330^{\circ}C$ for 3~5 h after pre-treatment at $250^{\circ}C$. The result of polarized optical microscope observation, mesophase is not observed in pitches carried out only pre-heat treatment. While mesophase content is significantly increased from 9% to 100% according to increasing secondary heat treatment time from 3 h to 5 h. Synthesizing of the mesophase pitch at low temperature of $330^{\circ}C$ is attributed to decrease of viscosity of the pitches carried out first heat treatment with $AlCl_3$. The result of Fourier-transform infrared spectroscopic analysis, it is expected that aromatization of aliphatic compounds is dominant at early secondary heat treatment, on the other hand, polycondensation reaction becomes dominant as secondary heat treatment time increases. Aromaticity and stacking height of the pitches secondary heat treated for 5 hours are more increased about 25% and 107%, respectively, than that of pitches carried out only first heat treatment.

• Composites Research
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• v.33 no.6
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• pp.329-335
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• 2020

In this study, the thermo-rheological behaivors of petroleum pitches with different softening points were studied, and a B-stage phenolic resins/petroleum pitches blends were prepared by adding petroleum pitches to the phenolic resins. As a result, the petroleum pitch with different softening points decreased the fluidity of the petroleum pitch as the Quinoline insoluble (QI) content increased and showed the viscous properties of the solid. In addition, the effect of adding petroleum pitches having different softening points on the thermo-rheological properties of phenolic resins was investigated. When petroleum pitch with a high softening point was added, the fluidity of the phenolic resin was reduced, and the hardening behavior was fast. It was possible to control the curing rate and curing behavior of the phenolic resin by adding petroleum pitches of different softening points. Among them, the phenolic resin mixture to which P-Pitch 2 was added has a higher fluidity than other blends under the same curing temperature condition.

• Carbon letters
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• v.24
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• pp.28-35
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• 2017

We demonstrated an effective way of preparing melt spinnable mesophase pitches via catalytic hydrogenation of petroleum residue (fluidized catalytic cracking-decant oil) and their subsequent thermal soaking. The mesophase pitches thus obtained were analyzed in terms of their viscosity, elemental composition, solubility, molecular weight, softening point and optical texture. We found that zeolite-induced catalytic hydrogenation under high hydrogen pressure contributed to a large variation in the properties of the pitches. As the hydrogen pressure increased, the C/H ratio decreased, and the solubility in n-hexane increased. The mesophase pitch with entirely anisotropic domains of flow texture exhibited good meltspinnability. The mesophase carbon fibers obtained from the catalytically hydrogenated petroleum residue showed moderate mechanical properties.

• Asia pacific journal of information systems
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• v.32 no.2
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• pp.275-306
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• 2022

Crowdfunding has emerged as an important financing source for diverse cultural projects and commercial ventures in the early stages. Unlike traditional investment evaluation, where structured financial data is critical, such information is typically unavailable for crowdfunding campaigns. Instead, campaign creators prepare pitches containing essential information about themselves and the campaigns, which are crucial in attracting and persuading contributors. Prior literature has examined the effects of different aspects in campaign pitches, but a comprehensive understanding of the theme is lacking. This study aims to fill this gap by identifying the lexicon of frequently used vocabulary in campaign pitches and examining how they are associated with crowdfunding success. Moreover, we examine how the association differs between culture and commercial crowdfunding campaigns. We randomly collected 50,000 campaigns from the cultural and commercial categories on Kickstarter and extracted the 100 most used verbs in the campaign pitches. Based on a machine learning approach combined with principal component analysis, we constructed sets of verbal factors statistically significant in predicting crowdfunding success. The findings also show that cultural and commercial campaigns consist of different verbal components with different effects on crowdfunding success.