An eigenvalue expansion technique for the stability evaluation of dual-spin vehicles and other gyroscopic systems

1974 ◽  
Author(s):  
J. MCINTYRE ◽  
T. ISAACS
Keyword(s):  
Stability Evaluation ◽  
Expansion Technique ◽  
The Stability ◽  
Gyroscopic Systems ◽  
Eigenvalue Expansion

Developing Stability of Posterior Mandibular Implants Placed With Osteotome Expansion Technique Compared With Conventional Drilling Techniques

2017 ◽  
Vol 43 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Yen-Ting Lin ◽  
Adrienne Hong ◽  
Ying-Chin Peng ◽  
Hsiang-Hsi Hong
Keyword(s):  
Bone Density ◽  
Surgical Techniques ◽  
Primary Stability ◽  
Conventional Technique ◽  
Implant Stability ◽  
Implant Stability Quotient ◽  
Expansion Technique ◽  
The Stability ◽  
Conventional Drilling ◽  
Secondary Stability

Clinical decisions regarding the stability and osseointegration of mandibular implants positioned using the bone expansion techniques are conflicting and limited. The objective was to evaluate the stability of implants placed using 2 surgical techniques, selected according to the initial width of the mandibular posterior edentulous ridge, with D3 bone density, during a 12-week period. Fifty-eight implants in 33 patients were evaluated. Thirty-two implants in 24 patients were positioned using the osteotome expansion technique, and 26 fixtures in 17 patients were installed using the conventional drilling technique. The implant stability quotient values were recorded at weeks 0, 1, 2, 3, 4, 6, 8, 10, and 12 postsurgery and evaluated using analysis of variance, independent, and paired t tests. Calibrated according to the stability reading of a 3.3-mm diameter implant, the osteotome expansion group was associated with a lower bone density than the conventional group (64.96 ± 6.25 vs 68.98 ± 5.06, P = .011). The osteotome expansion group achieved a comparable primary stability (ISQb-0, P = .124) and greater increases in secondary stability (ISQb-12, P = .07) than did the conventional technique. A D3 quality ridge with mild horizontal deficiency is expandable by using the osteotome expansion technique. Although the 2 groups presented similar implant stability quotient readings during the study period, the osteotome expansion technique showed significant improvement in secondary stability. The healing patterns for these techniques are therefore inconsistent.

scholarly journals Stability Evaluation Method of Hole Wall for Bored Pile under Blasting Impact

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 79
Author(s):  
Qiuwei Yang ◽  
Zhikun Ba ◽  
Zhuo Zhao ◽  
Xi Peng ◽  
Yun Sun
Keyword(s):  
Pile Foundation ◽  
Evaluation Method ◽  
Impact Load ◽  
Stability Evaluation ◽  
Foundation Construction ◽  
Concentration Problem ◽  
Hole Wall ◽  
Failure Theory ◽  
Collapse Failure ◽  
The Stability

Blasting impact load may be encountered during the construction of some pile foundation projects. Due to the effect of blasting impact, hole collapse can easily occur in the hole-forming stage of pile foundation construction. In order to prevent hole collapse, it is very necessary to evaluate the stability of a pile hole wall before pile foundation construction. The calculation of hole collapse can usually be attributed to an axisymmetric circular hole stress concentration problem. However, the existing collapse failure theory of pile hole hardly considers the effect of blasting impact load. In view of this, this paper proposes the stability evaluation method of a pile hole wall under blasting impact. Compared with the existing collapse failure theory, the proposed method fully considers the effect of blasting impact stress. Using Mohr–Coulomb strength theory and symmetry analysis, the strength condition of collapse failure is established in this work for accurate evaluation of the stability of a hole wall. The proposed stability evaluation method is demonstrated by a pile foundation construction project of a bridge. Moreover, a shaking table test on the pile hole model was performed to verify the proposed method by experimental data. The results indicate the effectiveness and usability of the proposed method. The proposed method provides a feasible way for the stability analysis of a pile hole wall under blasting impact.

scholarly journals Modeling of the emulsion stability using fractal dimensions

2008 ◽  
Vol 14 (3) ◽  
pp. 153-158 ◽  
Author(s):  
Snezana Pasalic ◽  
Predrag Jovanic
Keyword(s):  
Emulsion Stability ◽  
Fractal Dimensions ◽  
Ccd Camera ◽  
Stability Evaluation ◽  
Stable States ◽  
Water Emulsion ◽  
Box Counting Method ◽  
The Stability ◽  
The Moment ◽  
Life Circle

There are many developed strategies in the emulsion stability evaluation, for purpose of determining the life circle of emulsions. Most of them are based on the reological properties of the emulsions. There are very few which relay on the direct emulsion observations. In this paper we present the developed method for the emulsion stability evaluation by the direct observation of optical properties. As the stability quantification measure we propose the fractal dimension approach. The method is based on the measure of the emulsion transmittance properties, which are directly dependent on the emulsion stability at the moment of measurement. As the test emulsion the oil in the water emulsion was used. The system is classified as the stable emulsion and our intention was to find the moment when the emulsion starts to break. The emulsion transmittance properties were measured using an acquisition system, consisting of a CCD camera and a fast PC configuration equipped with the capturing software. The fractal dimensions were determined by the so called box counting method. The experimental emulsions were measured continuously within the period of 1200 h, from the moment of the emulsion creation. The changes of fractal dimensions were observed which indicates that the emulsion changed its state and therefore the stability during the time. Three regions of the emulsion life circle were divided according to the fractal dimensions measurement, which can be connected with the stable, unstable, and meta-stable states of the emulsion life circle. In the end, the model of the emulsion behavior was developed for the purpose of quantifying the changes in the experimental emulsion.

scholarly journals Quantum Mechanical-Based Stability Evaluation of Crystal Structures for HIV-Targeted Drug Cabotegravir

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7178
Author(s):  
Yanqiang Han ◽  
Hongyuan Luo ◽  
Qianqian Lu ◽  
Zeying Liu ◽  
Jinyun Liu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ab Initio ◽  
Crystal Structures ◽  
Structure Prediction ◽  
Hiv Infections ◽  
Integrase Inhibitor ◽  
Hiv Integrase ◽  
Stability Evaluation ◽  
The Stability ◽  
Long Acting

The long-acting parenteral formulation of the HIV integrase inhibitor cabotegravir (GSK744) is currently being developed to prevent HIV infections, benefiting from infrequent dosing and high efficacy. The crystal structure can affect the bioavailability and efficacy of cabotegravir. However, the stability determination of crystal structures of GSK744 have remained a challenge. Here, we introduced an ab initio protocol to determine the stability of the crystal structures of pharmaceutical molecules, which were obtained from crystal structure prediction process starting from the molecular diagram. Using GSK744 as a case study, the ab initio predicted that Gibbs free energy provides reliable further refinement of the predicted crystal structures and presents its capability for becoming a crystal stability determination approach in the future. The proposed work can assist in the comprehensive screening of pharmaceutical design and can provide structural predictions and stability evaluation for pharmaceutical crystals.

Structural Stability Evaluation for Lifting Lug Design of Large Marine Engine by Finite Element Analysis

2007 ◽  
Vol 353-358 ◽  
pp. 2855-2859
Author(s):  
W.C. Lee ◽  
Chae Sil Kim ◽  
J.B. Na ◽  
D.H. Lee ◽  
S.Y. Cho ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Design Procedure ◽  
Steel Structures ◽  
Stability Evaluation ◽  
Element Analysis ◽  
Marine Engines ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Three Dimensional Finite Element

Since most marine engines are generally very huge and heavy, it is required to keep safety from accidents in dealing them. Several types of lifting lugs have been used to assemble hundred ton–large steel structures and carry the assembled engines. Recently a few crashes have been occurred in carrying engines due to breaking down the lugs. Although the stability evaluation of the lifting lug has therefore been very important for safety, systematic design procedure of the lugs, which includes the structural analysis considering stability, has few reported. This paper describes the three dimensional finite element structural modeling for a lifting lug, the studies for determining the reasonable loading and boundary conditions, and the stability evaluation with the results of structural analyses. It should be very helpful for designing the other types of lifting lugs with safety.

Stability Evaluation of Karst Foundation Based on Orthogonal Test

2013 ◽  
Vol 807-809 ◽  
pp. 1725-1732
Author(s):  
Yi Ping Wu ◽  
Jian Hong Zhou ◽  
Qiu Xia Zhang ◽  
Zhong Jie Zhao
Keyword(s):  
Simulation Method ◽  
Orthogonal Test ◽  
Ratio Method ◽  
Stability Evaluation ◽  
Rock Slide ◽  
Factors Influencing ◽  
Object Based ◽  
Stability Maps ◽  
The Stability ◽  
Stability Results

Many State Grid projects of China are facing a series of natural disaster threats, such as landslide, collapse, mud-rock slide, etc. This article takes the Huangshi Daye Steel Substation as research object. Based on the orthogonal test which confirmed factors influencing the stability, it adopts the Numerical Simulation Method and the Roof Thickness-to-span Ratio Method to evaluate the stability of the Huangshi Daye Steel Substations karst foundation. By doing this, karst foundation stability maps of the substation are respectively obtained. Analyzing the stability results of the two methods, it has been found that the stability evaluation results measured by the two methods are the same. And orthogonal test has advantages such as comprehensiveness, speediness, reliability and accuracy. Meanwhile, according to the stability evaluation results, specific site operation suggestions are proposed.

scholarly journals The Stability Evaluation of Shaft during Drastic Drawdown Dewatering of Alluvium

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Mingze Du ◽  
Yanchun Xu ◽  
Heng Duan ◽  
Wen Li
Keyword(s):  
Coal Mine ◽  
Load Level ◽  
Stability Evaluation ◽  
Early Prevention ◽  
Discriminant Model ◽  
Fisher Discriminant ◽  
The Stability ◽  
And Control ◽  
Shaft Failure ◽  
Shaft Wall

The hydrophobicity of the aquifer at the bottom of the porous alluvium will affect the stability of the shaft. According to the changes of water level and the compressive amount of alluvium, we can evaluate the shaft stability and predict the shaft failure. In this work, the simulation model of the auxiliary shaft in the Zhuxianzhuang Coal Mine is generated by using the Nsdc software to evaluate the stability of the shaft during drastic drawdown dewatering. Based on the measured hydrophobic compression ratio in an adjacent coal mine, the compressive amounts of the strata near the main and auxiliary shafts in the Zhuxianzhuang Coal Mine are predicted under the condition of drastic drawdown dewatering, which will be 249.69 mm and 302.75 mm, respectively. It is more likely that the shaft wall may fracture in the 15th day (fourth load level) under the condition of drastic drawdown dewatering. The formation compressive amount near the auxiliary shaft is approximately 320 mm, which is close to the measured predicted value. At the same time, the Fisher discriminant model is established, and it is predicted that the state of the main and auxiliary shafts will be failure under the conditions of drastic drawdown dewatering in the Zhuxianzhuang Coal Mine. Based on the simulating results, the technical means of using the ground grouting for early prevention and control is proposed.

Study on the Stability Evaluation of Concrete Erosion Control Dam by using Non-destructive Test for Compressive Strength

2013 ◽  
Vol 102 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Ki-Hyung Park ◽  
Min-Sik Kim ◽  
Sung-Ho Joh ◽  
Chang-Woo Lee ◽  
Ho-Joong Youn ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Erosion Control ◽  
Stability Evaluation ◽  
Destructive Test ◽  
The Stability ◽  
Non Destructive
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