• Title/Summary/Keyword: Breaking force

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Development of 115K Tanker Design Adopted Ice Class 1A (Baltic Ice Class IA를 적용한 115K Ice Tanker 개발)

  • Kim, Hyun-Soo;Ha, Mun-Keun;Baek, Myeong-Chul;Kim, Soo-Young;Park, Jong-Woo;Chun, Ho-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.6
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    • pp.120-125
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    • 2004
  • There are very few numbers of 115K FPP (Fixed Pitch Propulsion) Tankers for the Baltic ice class IA because the minimum power requirement of FMA (Finish- Swedish Maritime Association) needs quite large engine power and the 40 m Beam is out of calculation range of FMA minimum power requirements. The shipyard has no choice except to increase the engine power to satisfy FMA minimum power requirement Rule. And the operation cost, efficiency of hullform and its building cost are not good from the ship owners' point of view To solve this problem, the experience of ice breaking tanker development and the ice tank test results were adopted. The main idea to reduce the ice resistance is by reducing waterline angle at design load waterline. The reason behind the main idea is to reduce the ice-clearing force. Two hull forms were developed to satisfy Baltic Ice class IA. Two ice tank tests and one towing tank test was performed at MARC (Kvaener-Masa Arctic Research Center) and SSMB (Samsung Ship Model Basin) facilities, respectively. The purpose of these tests was to verify the performance in ice and open water respectively The hull form 2 shows less speed loss compared to Hull form 1 in open water operation but hull form 2 shows very good ice clearing ability. finally the Hull Form 2 satisfying Baltic ice class IA. The merit of this hull form is to use the same engine capacity and no major design changes in hull form and other related designs But the hull structure has to be changed according to the ice class grade. The difference in two hull form development methods, ice model test methods and analysis methods of ice model test will be described in this paper.

Effect of Synnemata of Beauveria bassiana on the Properties of Noodle (백강균 자실체의 첨가가 제면적성에 미치는 영향)

  • Bae, Song-Hwan;Lee, Chan;Lee, Seok-Won;Yoon, Chul-Sik;Jung, Soo-Hyun
    • The Korean Journal of Food And Nutrition
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    • v.16 no.2
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    • pp.158-164
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    • 2003
  • This study was conducted to investigate the properties of noodle which was made of composite flour blended with the powder of synnemata of Beauveria bassiana. The characteristics of cooked-noodle including color, cooking properties, mechanical texture properties were measured, and sensory evaluation was performed. The L-value of dry and wet-noodle which made of composite flour was similar to that of 100% wheat flour, but a and b-value were higher than those of 100% wheat flour. There were no differences in the weight, volume and water absorption of the cooked-noodle made of composite flour and that of 100% wheat flour, but the turbidity of the cooked-noodle made of composite flour was higher than that of 100% wheat flour. The breaking force of dry-noodle which was made of composite flour was same as that of 100% wheat flour. Hardness and Gumminess of the cooked-noodle which was made of composite flour blended with synnemata powder at level of 1∼5% were same as those of 100% wheat flour. Springiness, chewiness, cohesiveness and adhesiveness of the cooked-noodle which was made of composite flour blended with synnemata powder at level of 1% were similar to those 100% wheat flour. The results of sensory evaluation showed that the cooked-noodles containing 1% and 3% synnemata powder were acceptable as much as those of 100% wheat flour in terms of color, taste, flavor, texture and overall acceptance.

Immobilization of Nitrifier Consortium for the Removal of Ammonium Ion in the Recirculating Aquaculture System (양어장수내의 암모니아성 질소제거를 위한 질화세균군의 고정화)

  • KIM Sung-Koo;SEO Jae-Koan;LEE Jong-Seok;KONG In-Soo;SUH Keun-Hack
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.5
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    • pp.816-822
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    • 1997
  • The immobilization of a microorganism has been rapidly progressed with the development of biotechnology in recent years. Although it has been used as a tool to isolate products from biological media in various areas, it has not yet been practiced in the treatment of waste water. In this paper, we suggest a possibility to apply the immobilization technique In the recirculating aquaculture system. We examined the ability of $NH_4^+$ removal by nitrifier consortium immobilized in $Ba^{++}-alginate$, k-carrageenan and agar bead at the concentration of 50 g/L, respectively. In order to use the immobilized nitrifier consortium as media in the fludized bed reactor, the strength of bead was measured. $Ba^{++}-alginate$ as a support material showed higher strength of bead. Also, the nitrifier consortium immobilized in $Ba^{++}-alginate$ showed higher nitrification activity that could remove 20 mg/L ammonium ion than those immobilized in other two support materials, carrageenan and agar. The immobilized nitrifier consortium showed better nitrification activity than free nitrifier consortium.

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The Nonlinear Motions of Cylinders(I) (주상체의 비선형 운동(I) -강제동요문제, 조파저항문제-)

  • H.Y. Lee;J.H. Hwang
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.4
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    • pp.114-131
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    • 1992
  • In the present work, a two-dimensional boundary-value problem for a large amplitude motion is treated as an initial-value problem by satisfying the exact body-boundary and nonlinear free-surface boundary conditions. The present nonlinear numerical scheme is similar to that described by Vinje and Brevig(1981) who utilized the Cauchy's theorem and assumed the periodicity in the horizontal coordinate. In the present thesis, however, the periodicity in the horizontal coordinate is not assumed. Thus the present method can treat more realistic problems, which allow radiating waves to infinities. In the present method of solution, the original infinite fluid domain, is divided into two subdomains ; ie the inner and outer subdomains which are a local nonlinear subdomain and the truncated infinite linear subdomain, respectively. By imposing an appropriate matching condition, the computation is carried out only in the inner domain which includes the body. Here we adopt the nonlinear scheme of Vinje & Brevig only in the inner domain and respresent the solution in the truncated infinite subdomains by distributing the time-dependent Green function on the matching boundaries. The matching condition is that the velocity potential and stream function are required to be continuous across the matching boundary. In the computations we used, if necessary, a regriding algorithm on the free surface which could give converged stable solutions successfully even for the breaking waves. In harmonic oscillation problem, each harmonic component and time-mean force are obtained by the Fourier transform of the computed forces in the time domain. The numerical calculations are made for the following problems. $\cdot$ Forced harmonic large-amplitude oscillation(${\omega}{\neq}0,\;U=0$) $\cdot$ Translation with a uniform speed(${\omega}=0,\;U{\neq}0$) The computed results are compared with available experimental data and other analytical results.

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A Study on the Proper Crown Height of GT 100,000Ton Cruise ship and DWT 100,000Ton Container ship (10만톤급 크루즈선과 컨테이너선의 적정 마루높이에 관한 연구)

  • Kim, Seungyeon;Lee, Yunsok
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.2
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    • pp.157-162
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    • 2018
  • The increase of risk in port due to the increase in ship size and sea level rises, the standard crown height will increase. In this study, cruise and container ships will need to raise their crown height due to the projected wind pressure areas becoming larger due to the ships' size increase. The mooring assessment was evaluated with the rise of the crown height. The cruise ship of GT 100,000 tons exceeded the permissible breaking force of the mooring line under the crown height conditions of wind speed of 30 kts when the wind direction was $45^{\circ}$ to the direction of the bow. Also, the elevation angle of the pier and mooring line was analyzed and exceeded the crown height, and it was determined that it is necessary to adjust the crown height. Container ships of DWT 100,000 tons were analyzed to exceed the limit of sway motion at the crown height and it was determined that they need to be adjusted to the minimum crown height standard.

Dynamical Analysis of the Mooring Vessel System Under Surge Excitations (선박 계류시스템의 종방향 외력하의 비선형 동적거동 해석)

  • Lee, Sang-Do;You, Sam-Sang
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.2
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    • pp.140-145
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    • 2018
  • This paper deals with the dynamical analysis of a two-point mooring vessel under surge excitations. The characteristics of nonlinear behaviors are investigated completely including bifurcation and limit cycle according to particular input parameter changes. The strong nonlinearity of the mooring system is mainly caused by linear and cubic terms of restoring force. The numerical simulation is performed based on the fourth order Runge-Kutta algorithm. The bifurcation diagram and several instability phenomena are observed clearly by varying amplitudes as well as frequencies of surge excitations. Stable periodic solutions, called the periodic windows, can be obtained in succession between chaotic clouds of dots in case of frequency ${\omega}=0.4rad/s$. In addition, the chaotic region is unexpectedly increased when external forcing amplitude exceeds 1.0 with the angular frequency of ${\omega}=0.7rad/s$. Compared to the cases for ${\omega}=0.4$, 0.7rad/s, the region of chaotic behavior becomes more fragile than in the case of ${\omega}=1.0rad/s$. Finally, various types of steady states including sub-harmonic motion, limit cycle, and symmetry breaking phenomenon are observed in the two-point mooring system at each parameter value.

An Experimental Study on New Type Chip Brakeer(Part 1) (신形 칩折斷具에 관한 實驗的 硏究 (제1보))

  • 손명환;이호철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.6
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    • pp.1121-1140
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    • 1992
  • In metal cutting the shape of generated chip varies according to cutting conditions, characteristics of workpiece and geometry of cutting tool. The best surface roughness of machined workpiece is obtained when generating flow type contrinuous chip. If the generated chip is not broken, that is not only tangled workpiece and cutting tool, but also may give damage on the machined surface of workpiece or danger for a operator. The flow type continuous chip may bring the low productivity in high speed any heavy cutting, automatic machining process and non-human factory. There are two type of chip break process ; controlling cutting condition and using chip breaker. In present study we carried out the experiment on new type chip breaker compared with conventional type and proved the efficiency of a new type and showed the chip break condition to be applied in actual metal cutting. In the experiment SM 20 C as a workpiece material and WC as a tool material were used and cutting speed of 30-150m/min, feed of 0.071-0.210mm/rev and depth of cut of 1mm were applied as cutting condition. The results of the experiment are as follows : (1) The mechanism of chip curl can be explained more clearly by plastic flow of workpiece material and moment of shearing force. (2) The most effective radius of curled chip and flat distance from cutting edge is 2.0-2.5mm and 1.5mm in both types. (3) The effective inclination angle of chip break surface and side cutting edge angle are 30.deg.- 45.deg. and 20.deg. in conventional type, while the radius of arc surface, lower arc angle A, upper arc angle B and side cutting edge angle are 3mm, 20.deg.- 45.deg., 0.deg.- 45.deg. and 10.deg.- 20.deg. in new type. (4) The probability to be obtained 100% chip breaking ratio is much higher in new type than in conventional type.

Rheological Properties of Heat-Induced Gels of Surimi from Acid and Alkali Process (산 및 알칼리 공정으로 조제한 수리미 가열 겔의 물성 특성)

  • Choi Young Joon;Park Joo Dong;Kim Jin Soo;Cho Young Jae;Park Jae W.
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.35 no.4
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    • pp.309-314
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    • 2002
  • Rhtological properties of surimi gel from white fishes by acid (acid surimi) and alkali (alkali surmi) process and effect of chemicals on gelation were investigated by punch and dynamic tests. The breaking force and deformation values of heat-induced gel of acid surimi were less than their values of alkali and conventional surimi gel, and whiteness was greatly decreased, Gel point of acid surimi was decreased but it of alkali surimi was increased with increasing moisture content in the range of 80 to $85\%$. Storage modulus of acid surimi was the highest vaule in pH 6.8, but that of alkali surimi showed high value at neutral and slightly alkali pH. Propylene glycol increased storage modulus in $20\~50^{\circ}C$, hut urea and 2-mercaptoethanol suppressed it. Potassium bromide improved storage modulus in $20~80^{\circ}C$, The results suggest that alkai process is used for making surimi instead of conventional method.

In vitro study of compressive fracture strength of Empress 2 crowns cemented with various luting agents

  • Kim Min-Ho;Yang Jae-Ho;Lee Sun-Hyung;Chung Hun-Young;Chang Ik-Tae
    • The Journal of Korean Academy of Prosthodontics
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    • v.39 no.3
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    • pp.260-272
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    • 2001
  • All-ceramic restorations have had a more limited life expectancy than metal ceramic restorations because of their low strength. Their relatively lower strength and resistance to fracture have restricted the use of all-ceramic crowns to anterior applications where occlusal loads are lower. But there has been increasing interest in all-ceramic restorations because patients are primarily concerned with improved esthetics. Many efforts have been made to in prove the mechanical properties of dental ceramics. This study was designed to elucidate the influence of the luting agent on the strength of the Empress 2 crown (staining technique) cemented on human teeth. Seventy extracted human permanent molar teeth were chosen. Teeth were prepared for Empress 2 crowns with milling machine on a surveyor. A dental bur was placed in the mandrel that was positioned so that the long axis of the bur was perpendicular to the surveyor base. Dimensions of the Empress 2 crown preparation were $6^{\circ}$ taper on each side, $1.5{\pm}0.1mm$ shoulder margin, and 4mm crown height. The luting cements used in this study were as follow: 1. Uncemented 2. Zinc phosphate cements (Confi-Dental) 3. Conventional glass ionomer cement : Fuji 1 (GC) 4. Resin-modified glass ionomer cements : Fuji plus (GC) 5. Adhesive cements : Panavia F (Kuralay), Variolink II (Vivadent), Choice (Bisco). Fracture test using Instron. The crowns were loaded in compressive force to evaluate the effect of these cements on the breaking strength of these all-ceramic crowns. A steel ball with a diameter of 4mm was placed on the occlusal surface and load was applied to the steel ball by a cylindrical bolt with a crosshead speed of 0.5mm per minute until fracture occurred. The fractured surface was examined using Scanning Electron Microscopic Image (SEM) to discover the correlation between fracture strength and bonding capacity. Within the limitation of this in vitro study design, the results were as follows : 1. fomentations significantly increased the fracture resistance of Empress ceramic crowns compared to control. Uncemented (206.9 N): ZPC (812.9 N): Fuji 1 (879.5 N): Fuji Plus (937.7 N): Choice (1105.4 N): Variolink II (1221.1 N): Panavia F (1445.2 N). 2. Resin luting agent, treated by a silane bond enhancing agents, yielded a significant increase in fracture resistance. In some of the Panavia F group, a fracture extended into dentin. 3. According to SEM images of fractured Empress crowns, the stronger the bond at both interfaces(crown and die), the more fracture strength was acquired.

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A Study on the Communication of the Functional Family (기능적인 가족의 커뮤니케이션에 관한 이론적 접근)

  • 조윤경
    • Journal of Families and Better Life
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    • v.2 no.1
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    • pp.131-150
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    • 1984
  • The purpose of this study is to explore the family as an interaction system, concentrating on the mutual influences between communication and family development; (1) how Communication patterns affect family relationships, and (2) how relationships among family members affect communication. In order to do this Galvin, Brommel used the following frame work; family is a system in which communication regulates cohesion and adaptability by a flow of message patterns through a defined network of evolving interdependent relationships. A family system consists of members, the relationships among them, the family attributes, the members attributes and an environment in which family functions. Within the framework of common cultural communication patterns, each family has the capacity to develop its own communication code based on the experiences of individual members and the collective family experience. Most of us develop our communication skills within the family context learning both the general cultural language and the specific familial communication code. Communication may be viewed as a symbolic, transactional process as the process of creating and sharing meanings. To say that communication is a process implies a continuous interaction of an indefinite large numbers of variables with a concomitant,. continuous change in the values taken by these variables. Finally the process implies change, Family functions include the primary functions of cohesion and adaptability, and supporting functions of family images, themes, boundaries, and biosocial issues. The primary functions reveal concepts integrated family interaction and supporting function, along with those of cohesion and adaptability, give shape to family life. the characteristics of developed relationships of richness, uniqueness efficiency, substitutability, pacing , openness spontaneity, and evaluation are reflected in the verbal and nonverbal behaviors with which family members negotiated a set of common meanings and develop thier own unique message system. The message system is the major element of communication process and influences both the form and the content of thier relationship and in create and share meanings. Family systems need to provide order and predictability for thier members, specifically focusing on communication rules and the networks by which messages are transmitted. Most rules emerge as a result of multiful interactions. There are basic rules and rules about rules, or metarules. Perceiving the rules of family system is very difficult because often family members don't think about the basic rules, much less the metarules. Breaking the rule may result in the creation of a new set because the system may recalibrate itself to accept more variety of behavior. Families develop communication networks to deal with the general issue. Family adaptability may be seen through the degree of flexibility in forming and reforming networks and networks become a vital part of the decision- making process and relate to the power dynamics operating within the family. Networks also play an integral part in maintaining the roles and rules operating with the family system. Thus networks and rules have mutual influence. The family -of -origin issues influence all aspects of family communication and account for many of the communication patterns, rules and networks and the role of the family -of-origin influences as a primary force for communication on behavior of newly forming systems. Each family system develops its own communication meanings. There is not one right way to communicate within a family but may be indefinitly large change of family life and communication behavior. Study on functional family communication helps to gain a better understanding of dynamics of family communication and ability of a new insight into the family.

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