• International Journal of Fluid Machinery and Systems
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• v.8 no.2
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• pp.63-72
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• 2015

Water hammer phenomena are important issues for the design and the operation of hydro power plants. Especially, if several reversible pump-turbines are coupled hydraulically there may be strong unit interactions. The precise prediction of all relevant transients is challenging. Regarding a recent pump-storage project, dynamic measurements motivate an improved turbine modeling approach making use of a Thoma number dependency. The proposed method is validated for several transient scenarios and turns out to improve correlation between measurement and simulation results significantly. Starting from simple scenarios, this allows better prediction of more complex transients. By applying a fully automated simulation procedure broad operating ranges of the highly nonlinear system can be covered providing a consistent insight into the plant dynamics. This finally allows the optimization of the closing strategy and hence the overall power plant performance.

• Journal of Periodontal and Implant Science
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• v.47 no.1
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• pp.2-12
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• 2017

The aim of this narrative review is to describe treatment options for the posterior regions of the mandible and the maxilla, comparing short implants vs. longer implants in an augmented bone. The dental literature was screened for treatment options enabling the placement of dental implants in posterior sites with a reduced vertical bone height in the maxilla and the mandible. Short dental implants have been increasingly used recently, providing a number of advantages including reduced patient morbidity, shorter treatment time, and lower costs. In the posterior maxilla, sinus elevation procedures were for long considered to be the gold standard using various bone substitute materials and rendering high implant survival rates. More recently, implants were even placed without any further use of bone substitute materials, but the long-term outcomes have yet to be documented. Vertical bone augmentation procedures in the mandible require a relatively high level of surgical skill and allow the placement of standard-length dental implants by the use of autogenous bone blocks. Both treatment options, short dental implants, and standard-length implants in combination with vertical bone augmentation procedures, appear to result in predictable outcomes in terms of implant survival rates. According to recent clinical studies comparing the therapeutic options of short implants vs. long implants in augmented bone, the use of short dental implants leads to a number of advantages for the patients and the clinician.

• The Korean Journal of Zoology
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• v.19 no.3
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• pp.101-112
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• 1976

1. It has been found in the karyotype of Apodemus agrarius coreae that No. 1 chromosome pair is subtelocentric and this is the new chromosome type in comparison with acro-telocentric No. 1 pair of the other subpecies. 2. It was reported in the Karyotype of Microtus fortis from USSR that the autosome consisted of 2 submetacentric, 10 metacentric and 38 acrocentric chromosomes, and that X is acrocentric and Y is small acrocentric one. In the present study, however, the autosome of M. fortis pelliceus in Korea is composed of three groups; 4 subtelocentric, 10 meta-submetacenric, and 36 acrocentric one. And X is the largest metacentric chromosome of the complement. Y is smaller acrocentric one. Thus, it has been found that the karyotype of M. fortis in Korea differs from that of the same species in USSR. In the karyotype of this red vole, two pairs of heteromorohic chromosome with respect to the size of their secondary constrictions have been shown in the acrocentric group. 3. The diploid number of Cricetulus triton nestor was found to be 28, and its chromosome size ranges from 7.5 $\\mu$ to 1.5 $\\mu$. Autosomes contains 11 large acrocentric pairs and two pairs of very small metacentric ones. This feature is simillar to that of Tscherskia triton found USSR.