• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.46-53
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• 2002

Push-pull strength has been found to be associated with various work factors such as height, distance, repetition, duration, posture and individual factors. Therefore, this study was performed to investigate the effect of various work factors on push-pull strength and muscle recruitment pattern. Work factors were consisted of grip height(elbow, shoulder), grip distance(100%, 50%, and 25% of maximum grip distance) and shoulder angle(neutral($90^{\cire}$), and abduction($45^{\cire}$, $0^{\cire}$)) during sitting work. The results showed that the normalized strength and EMG value were higher at the elbow height than the shoulder height, and increased with grip distance and shoulder adduction. The results of ANOVA showed that there was significant difference on muscle recruitment patterns among the task conditions. Therefore, it is necessary to consider work factors as well as strength to prevent workers from work-related injuries.

• Journal of the Ergonomics Society of Korea
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• v.32 no.4
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• pp.405-411
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• 2013

Objective: Product design process without considering the strength of the user can cause the excessive burden on musculoskeletal system of human body. Since the muscle strength will vary depending on the body posture, the design of product should consider the characteristics of body posture. This study was performed to investigate the effects of forearm postures on the push and pull strength. Background: Overexerted force has been identified to cause musculoskeletal disorders. It is important to know the push and pull strength exerted by human when designing so that exerted force does not exceed the safety limits. Method: Maximum isometric push and pull strength of left, right and both hands were measured according to forearm postures with pronation, neutral and supination. For the study, 66 male and 30 female undergraduate students were participated as subjects. All subjects were normal and healthy with no clinical history. Results: The results showed that the push strength of male and female were 93.3% and 85.4% of pull strength. It showed that the strength of one-hand was 72.1~81.0% of the strength of two-hands, and the strength of left hand was 93.1~95.8% of the strength of right hand. The strength of female was 62% of the one of male. It was found that the strength with pronation $90^{\circ}$ was reduced up to 20% compared to the strength with neutral posture. Conclusion: Push and pull strength of male and female were reduced when forearm was rotated extremely. Application: The results of this study will be used for the prevention of work related musculoskeletal disorders and design of industrial equipment.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.63-68
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• 2002

This study performed to evaluated musculoskeletal disorders(MSDs) during sitting work. The musculskeletal system is affected by various work factors such as strength, weight, posture, repetition, duration and exertion. Ergonomic study on sitting work is necessary to evaluate these factors affecting human body. But the strength and work load data by the work factors are insufficient in Korea. Therefore, this study evaluated the work load using the elcctromyogram(EMG) and measured the arm strength by arm posture and push pull work during sitting work. to evaluated muscle load, the vertical height and horizontal angle of arm were adjusted around acromion. And EMG data were recorded on pc during the test.

• Industrial Engineering and Management Systems
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• v.6 no.1
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• pp.83-93
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• 2007

This paper gives an attempt to build a decision support tool linked with a simulation software called ARENA for evaluating and comparing the performance of the push and pull material driven strategies operating in the flow shop environment with a bottleneck resource as the shop's constraint. To be fair for such evaluation, the comparison must be made fairly under the optimal setting of both systems' operating parameters. In this study, an optimal-seeking heuristic algorithm, Genetic Algorithm (GA), is employed to suggest a systems' best design based on the economic consideration, which is the profit generated from the system. Results from the study have revealed interesting outcomes, letting us know the strength and weakness of the push and pull mechanisms as well as the effect of each operating parameter to the overall system's financial performance.

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.37.1-37.10
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• 2019

Objectives: This study evaluated the bond strength of various fiberglass post cementation techniques using different resin-based composites. Materials and Methods: The roots from a total of 100 bovine incisors were randomly assigned to 5 treatment groups: G1, post + Scotchbond Multi-Purpose (SBMP) + RelyX ARC luting agent; G2, relined post (Filtek Z250) + SBMP + RelyX ARC; G3, individualized post (Filtek Z250) + SBMP; G4, individualized post (Filtek Bulk-Fill) + SBMP; G5, individualized post (Filtek Bulk-Fill Flow) + SBMP. The samples were subjected to the push-out (n = 10) and pull-out (n = 10) bond strength tests. Data from the push-out bond strength test were analyzed using 2-way analysis of variance (ANOVA) with the Bonferroni post hoc test, and data from the pull-out bond strength test were analyzed using 1-way ANOVA. Results: The data for push-out bond strength presented higher values for G2 and G5, mainly in the cervical and middle thirds, and the data from the apical third showed a lower mean push-out bond strength in all groups. No significant difference was noted for pull-out bond strength among all groups. The most frequent failure modes observed were adhesive failure between dentine and resin and mixed failure. Conclusions: Fiberglass post cementation using restorative and flowable bulk-fill composites with the individualization technique may be a promising alternative to existing methods of post cementation.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.19-22
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• 1995

A biomechanical study was made to demonstrate the superior mechanical performance of the newly designed Miniplate staple to the conventional Coventry staple in high tibial osteotomy(HTO). Using twenty fresh porcine tibiae, the fixational strengh of the two different types of staple in HTO was compared. To minimize the error due to the specimen-to-specimen individuality, the bone mineral density of the tibiae was measured with a bone densitometry (Dual photon absorptionometer, Luner, USA) and those with $0.8\;{\sim}\;1.2\;gm/cm^2$ at the proximal tibia was used in the biomechanical test. Testing was performed on a material testing system (Autogram ET-5, Shimatzu, Japan) with aid of a commercial data processor (IBM 80386/ ASYST). Using two differant loading modes, 'pull-out' and 'push-out', the maximum resistant force required to release the staple from the substrate bone was recorded. In the pull-out test, ten non-osteotomized specimens were used and the staple was pullout by subjecting an axial tension on the head of the staple inserted. While in the pull-out test where ten tibiae osteotomized in the usual way of HTO were used, the staple was not directly loaded. In this testing, as a mimic condition of the natural knee, the distal part of the specimen tibia was pushed horizontally in order for the staple to be pulled out while the proximal tibia was fixed. The pull-out strength of Coventry staple and miniplate staple were found to be $27.88\;{\pm}\;5.12\;kgf$ and $182.47\;{\pm}\;32.75\;kgf$, respectively. The push-out strength of Coventry staple and miniplate staple were $18.40\;{\pm}\;4.47\;kgf$ and $119.95\;{\pm}\;19.06\;kgf$, respectively. The result revealed that miniplate staple had the pull-out/ push-out strength at least fivetimes higher than Coventry staple. Based on the measured data, it was believed that the newly designed miniplate staple could provide much better postoperative fixation in HTO. The postoerative application of long leg casting may not be needed after HTO surgery.

• Clinics in Shoulder and Elbow
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• v.21 no.4
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• pp.246-251
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• 2018

Compared to single row repair, use of lateral row anchors in suture bridge rotator cuff repair enhances repair strength and increases footprint contact area. If a lateral knotless anchor (push-in design) is inserted into osteoporotic bone, pull-out of the lateral row anchor can developed. However, failures of lateral row anchors have been reported at several months after surgery. In our cases, even though complete cuff healing occurred, delayed pull-out of the lateral row anchor in the suture bridge repair occurred. In comparison to a conventional medial anchor, further biomechanical evaluation of the pull-out force, design, and insertion angle of the lateral anchor is needed in future studies. We report three cases with delayed pull-out of lateral row anchor in suture bridge rotator cuff repair with a literature review.

• Journal of the Ergonomics Society of Korea
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• v.9 no.2
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• pp.37-45
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• 1990

This study investigated the muscular strength of 77 Korean young males aged 19-23 in 1989. The maesure- ment items were grip strength, back strength, push and pull strength at each of 3 elbow angles, and torque strength. The results of this study were compared with those of the past survey and the foreign surveys. Besides, sample correlation coefficients were calculated in order to analyze the relationship between muscular strengths and anthropometric dimensions.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.2
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• pp.105-117
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• 2015

The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were experimentally performed on one unreinforced beam-column specimen and two reinforced specimens with L-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of L-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D except for the equation to predict the concrete breakout failure strength at the concrete side, principally agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.101-111
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• 2021

Two different types of shear-friction tests were classified by external loadings and referred to as a push-off and a pull-off test. In a pull-off test, a tension force is applied in the transverse direction of the test specimen to produce a shear stress at the shear plane. This paper presents a method to evaluate shear transfer strengths of uncracked pull-off specimens. The method is based on the compression field theory and different constitutive laws are applied in some ways to gain accurate shear strengths considering softening effects of concrete struts based on Modified Compression Field Theory (MCFT) and Softened Truss Model (STM). The validity of the proposed method is examined by applying to some selected test specimens in literatures and results are compared with the predicted values. A general agreement is observed between predicted and measured values at ultimate loading stages in initially uncracked pull-off test specimens. A shear strength evaluation formula considering the effective compressive strength of a concrete strut was proposed, and the applicability of the proposed formula was verified by comparing with the experimental results in the literature.