• Applied Chemistry for Engineering
• /
• v.9 no.3
• /
• pp.322-329
• /
• 1998

Chemical bonding was investigated in the simulated body fluid of several selected hydroxyapatite-containing composites. The hydroxyapatite-containing composites chemically bonded with each other in the simulated body fluid after 4 weeks. Bioglass was strongly bonded in the simulated body fluid, but bonding strength was not depended on composition. Their composite bodies were chemically bonded by heterogeneous nucleation and growth at the interfaces of the specimens in the simulated body fluid.

• Journal of muscle and joint health
• /
• v.13 no.1
• /
• pp.7-19
• /
• 2006

Falls are a major sources of death and injury in elderly people. Aged-related changes in the physiological systems which contribute to the maintenance of balance are well documented in older adults. These changes coupled with age-related changes in muscle and bone are likely to contribute to an increased risk of falls in this population. Regular exercise may be one way of preventing falls and fall-related fractures. However, the optimal exercise prescription to prevent falls has not yet been defined. On the literature review of exercise intervention for fall prevention in the elderly, exercise appeared to be a useful tool in fall prevention by improving fall risk factors. The optimum exercise prescription; moderate intensity frequency of 3-4 times per week, duration of 30-60minutes can contribute to decreased hazards and number of fall. Fall prevention protocol should include safety, falling effect, enjoyment, and easiness to follow for older people. Effective exercise programs suggested for fall prevention were such as weight-bearing exercise, resistance exercise, lower muscle strength with elastic band, swiss ball exercise walking, tai chi, and yoga.

• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.4
• /
• pp.338-344
• /
• 2017

Polyoxometal molybdophosphoric acid (MoPA) bonded polyether ether ketone (PEEK) composite membrane for water electrolysis has been investigated. The composited membrane, covalently cross linked (CL) sulfonated polyether ether ketone (SPEEK) with a bonded MoPA, was prepared in sulfonation of PEEK, cross linkage reaction with 1,4-diiodobutane, and addition with MoPA. PEEK was covalently cross-linked with 1,4-diiodobutane to improve mechanical strength and was added with MoPA to increase proton conductivity. MoPA should be fixed to back bone of SPEEK to prevent bleeding out. Therefore, the carbonyl group of SPEEK was reduced with NaBH4 and 3-isocyanatepropyltriethoxysilane (ICPTES) was added. The MoPA bonded composite was produced in the reaction of MoPA with 3-mercaptopropyltrimethoxvsilane (MPTMS). In conclusion, MoPA bonded CL-SPEEK composite membrane featured 0.129 S/cm of proton conductivity at $80^{\circ}C$, and 2,156 hours of chemical stability in Fenton test. These properties are better than those of membranes of other SPEEK system.

• Computers and Concrete
• /
• v.14 no.2
• /
• pp.193-209
• /
• 2014

Cyclic test of the columns is of practical relevance to the performance of compression members during an earthquake loading. The strength, ductility and energy absorption capabilities of reinforced concrete (RC) columns subjected to cyclic loading have been estimated by many researchers. These characteristics are not normally inherent in plain concrete but can be achieved by effectively confining columns through transverse reinforcement. An extensive experimental program, in which performance of four RC columns detailed according to provisions of ACI-318-08 was studied in contrast with that of four columns confined by a new proposed technique. This paper presents performance of columns reinforced by standard detailing and cast with 25 and 32 MPa concrete. The experimentally achieved load-displacement hysteresis and backbone curves of two columns are presented. The two approaches which work in conjunction with Response 2000 have been suggested to draw analytical back bone curves of RC columns. The experimental and analytical backbone curves are found in good agreement. This investigation gives a detail insight of the response of RC columns subjected to cyclic loads during their service life. The suggested analytical procedures will be available to the engineers involved in design to appraise the capacity of RC columns.

• Fisheries and Aquatic Sciences
• /
• v.17 no.2
• /
• pp.175-180
• /
• 2014

The present study was conducted to characterize physicochemical properties of chub mackerel bones (CMB) to evaluate its potential as a food resource. The proximate composition of CMB showed 40.4% moisture, 13.8% crude fat, 15.2% crude protein, and 28.7% ash. The major minerals in CMB were calcium (26.27 g/100 g) and phosphorus (15.88 g/100 g). The amino acids were rich in glycine, proline, glutamic acid, and alanine. The contents of total and neutral lipids, glycolipid and phospholipid were shown to be 16.05%, 95%, 2.32%, and 3.15%, respectively. The major fatty acids were C22:6, C16:0, C18:1, C20:5, C18:0, C17:0, C14:0, C20:1 in order. The fatty acid contents of total and neutral lipid were in a range of 39.25% and 44.54% for saturated and 33.61% and 34.05% for polyunsaturated, respectively. The breaking strength and hardness of intact CMB were 10.01 and $50.03kgf/cm^2$, whereas those of CMB heated for 45 min at $121^{\circ}C$ were 0.40 and $1.94kgf/cm^2$, respectively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.28 no.1
• /
• pp.16-23
• /
• 2002

To understand the micro-mechanical changes and the effects of the fluoride on rat's femur after administration of sodium fluoride, the three-point bending test, acoustic emission analysis during the three-point bending test and scanning electron microscopy were performed. The obtained results were as follows: 1. Bone strength increased in the rats given 1, 5, 10 and 20 ppm of fluoride but, there were no statistical significances (p>0.05). 2. With increasing the concentration of fluoride, most AE events released rapidly just before the maximum load and smaller events were recorded than the control group's. The average of cumulative AE event counts until maximum load of the femur in 20 ppm group were significantly small with respect to the control group's (p<0.05). 3. Fracture surfaces were well coincide with the results of acoustic emission behavior. Analyses of fracture surfaces indicated that, consistent with its the highest load, rat femur in 20 ppm fluoride group displays the roughest surface.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.2
• /
• pp.207-220
• /
• 2015

This study identified the species-specific, frequency-dependent characteristics of broadband acoustic scattering that facilitate classifying fish species using the pulse compression (PC) technique. Controlled acoustic scattering laboratory experiments were conducted with nine commercially important fish species using linear chirp signals (95-220 kHz) over an orientation angle range of ${\pm}45^{\circ}$ in the dorsal plane at approximately $1^{\circ}$ increments. The results suggest that the angular-dependent characteristics of the broadband echoes and the frequency-dependent variability in target strength (TS) were useful for inferring the fish species of interest. The scattering patterns in the compressed pulse output were extremely complex due to morphological differences among fish species, but the x-ray images strongly suggested that spatial separation correlated well with scattering for the head, skeleton, bone, otoliths, and swim bladder within each specimen.

• Archives of Craniofacial Surgery
• /
• v.20 no.6
• /
• pp.347-353
• /
• 2019

Most orbital surgeons believe that it's difficult to restore the primary orbital wall to its previous position and that the orbital wall is so thin that cannot be firmly its primary position. Therefore, orbital wall fractures generally have been reconstructed by replacing the bony defect with a synthetic implant. Although synthetic implants have sufficient strength to maintain their shape and position in the orbital cavity, replacement surgery has some drawbacks due to the residual permanent implants. In previous studies, the author has reported an orbital wall restoring technique in which the primary orbital wall fragment was restored to its prior position through a combination of the transorbital and transantral approaches. Simple straight and curved elevators were introduced transnasally to restore the orbital wall and to maintain temporary extraorbital support in the maxillary and ethmoid sinus. A transconjunctival approach provided sufficient space for implant insertion, while the transnasal approach enabled restoration of the herniated soft tissue back into the orbit. Fracture defect was reduced by restoring the primary orbital wall fragment to its primary position, making it possible to use relatively small size implant, furthermore, extraorbital support from both sinuses decreased the incidence of implant displacement. The author could recreate a natural shape of the orbit with the patient's own orbital bone fragments with this dual approach and effectively restored the orbital volume and shape. This procedure has the advantages for retrieving the orbital contents and restoring the primary orbital wall to its prior position.

• Computers and Concrete
• /
• v.26 no.5
• /
• pp.451-465
• /
• 2020

This paper presents experimental and numerical investigations on mechanical properties of ultra-high-performance fiber-reinforced concrete (UHPFRC) with four types of steel fibers; micro steel (MS), crimped (C), round crimped (RC) and hooked-end (H), in two fiber contents of 1% and 2% (by volume) and two lengths of 13 and 30 mm. Compression, direct tension, and four-point bending tests were carried out on four types of specimens (prism, cube, dog-bone and cylinder), to study tensile and flexural strength, fracture energy and modulus of elasticity. Results were compared with UHPC specimens without fibers, as well as with available equations for the modulus of elasticity. Specimens with MS fibers had the best performance for all mechanical properties. Among macro fibers, RC had better overall performance than H and C fibers. Increased fibers improved all mechanical properties of UHPFRC, except for modulus of elasticity, which saw a negligible effect (mostly less than 10%). Moreover, nonlinear finite element simulations successfully captured flexural response of UHPFRC prisms. Finally, nonlinear regression models provided reasonably well predictions of flexural load-deflection behavior of tested specimens (coefficient of correlation, R² over 0.90).

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.6
• /
• pp.784-790
• /
• 2014

In this study we aimed to evaluate the reduction in dimensionality of 20 linear type traits and more final score in 14,943 Holstein cows in Brazil using factor analysis, and indicate their relationship with longevity and 305 d first lactation milk production. Low partial correlations (-0.19 to 0.38), the medium to high Kaiser sampling mean (0.79) and the significance of the Bartlett sphericity test (p<0.001), indicated correlations between type traits and the suitability of these data for a factor analysis, after the elimination of seven traits. Two factors had autovalues greater than one. The first included width and height of posterior udder, udder texture, udder cleft, loin strength, bone quality and final score. The second included stature, top line, chest width, body depth, fore udder attachment, angularity and final score. The linear regression of the factors on several measures of longevity and 305 d milk production showed that selection considering only the first factor should lead to improvements in longevity and 305 milk production.