scholarly journals Analysis of Sensitive Parameters Affecting Unlocking Force of Finger Lock in Landing Gear

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Yu Hou ◽  
Ming Zhang ◽  
Hong Nie
Keyword(s):  
Mechanical Characteristics ◽  
Landing Gear ◽  
Effective Coefficient ◽  
Wear Model ◽  
Obvious Effect ◽  
Working Cycle ◽  
Inner Surface ◽  
Surface Diameter ◽  
Lock In ◽  
Sensitive Parameters

The mechanical characteristics of the unlocking force of the landing gear finger lock were studied in this paper, the influence of its diameter, fingertip angle, wear, and other factors on the unlocking force in one complete working cycle was analyzed, and the sensitive parameters that affect the unlocking force were obtained. Firstly, the unlocking force and wear of finger lock were calculated theoretically, and the changing rule of the unlocking force and wear with each parameter was obtained. Then, the validity of the correlation coefficient and model was verified by experiment. Finally, combined with the effective coefficient obtained from the experiment, the Archard wear model was used to simulate the change rule of lock force. The results show that in one complete working cycle, the inner surface diameter is negatively related to the unlocking force, fingertip diameter has little effect on the unlocking force, fingertip angle is negatively related to the unlocking force, and wear is positively related to the unlocking force; friction coefficient and fingertip angle are high sensitive parameters that affect the unlocking force, which have obvious effect on the unlocking force. The inner surface diameter, fingertip diameter of finger lock, and wear are the low sensitive parameters that affect the unlocking force, and the influence on the unlocking force is weak.

Modeling of the vibroacoustic dynamic system “machined workpiece-slide” of turning center

2021 ◽  
pp. 531-536
Author(s):  
V.F. Bez’yazychny ◽  
A.N. Chukarin ◽  
P.V. Chumak
Keyword(s):  
Dynamic System ◽  
Mechanical Characteristics ◽  
Cutting Tool ◽  
Vibration Energy ◽  
Energy Losses ◽  
Effective Coefficient ◽  
Absorbing Materials ◽  
Turning Center ◽  
Force Impact ◽  
Physical And Mechanical Characteristics

Settlement dependences on determining the vibration characteristics of the machined workpieces, taking into account geometric, physical and mechanical characteristics and the force impact from the side of the cutting tool are established. In determining the dependences the effective coefficient of vibration energy losses was taken into account, providing the required value of which, is achieved by reducing vibration in the source due to the use of vibration-absorbing materials.

scholarly journals Effective coefficient of diffusion and permeability of firn at Dome C and Lock In, Antarctica – Estimates over the 100–850 kg m<sup>−3</sup> density range

2021 ◽  
Author(s):  
Neige Calonne ◽  
Alexis Burr ◽  
Armelle Philip ◽  
Frédéric Flin ◽  
Christian Geindreau
Keyword(s):  
Diffusion Coefficient ◽  
Analytical Models ◽  
Density Range ◽  
Effective Coefficient ◽  
Structural Anisotropy ◽  
Near Surface ◽  
Tomographic Images ◽  
Porosity Ratio ◽  
Lock In ◽  
Coefficient Of Diffusion

Abstract. Modeling air transport through the entire ice sheet column is needed to interpret climate archives. To this end, different regressions were proposed to estimate the effective coefficient of diffusion and permeability of firn. Such regressions are often valid for specific depth or porosity ranges and were little evaluated as data of these properties are scarce. To contribute with a new dataset, this study presents the effective coefficient of diffusion and the permeability at Dome C and Lock In, Antarctica, from the near-surface to the close-off (23 to 133 m depth). Also, microstructure is characterized based on density, specific surface area, closed porosity ratio, connectivity index and structural anisotropy through the correlation lengths. All properties were estimated based on pore-scale computations on 3D tomographic images of firn samples. Normalized diffusion coefficient ranges from 1.9 × 10−1 to 8.3 × 10−5 and permeability ranges from 1.2 × 10−9 to 1.1 × 10−12 m2, for densities between 565 and 888 kg m−3. No or little anisotropy is reported. Next, we investigate the relationship of the transport properties with density over the firn density range as well as over the entire density range encountered in ice sheets by including snow data. Classical analytical models and regressions from literature are evaluated. For firn (550–850 kg m−3), good agreements are found for permeability and diffusion coefficient with the regressions based on the open porosity of Freitag et al. (2002) and Adolph and Albert (2014), despite the rather different site conditions (Greenland). Over the entire 100–850 kg m−3 density range, permeability is accurately reproduced by the Carman-Kozeny and Self-Consistent (spherical bi-composite) model when expressed in terms of a rescaled porosity ϕres = (ϕ–ϕoff) / (1–ϕoff) to account for pore closure, with ϕoff the close-off porosity. For the normalized diffusion coefficient, none of the evaluated formulas were satisfactory so we propose a new regression based on the rescaled porosity that reads D/Dair = (ϕres)1.61.

scholarly journals Wear analysis of finger locks with different design parameters for landing gear

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042095012
Author(s):  
Yu Hou ◽  
Ming Zhang ◽  
Hong Nie
Keyword(s):  
Axial Force ◽  
Landing Gear ◽  
Transition Phase ◽  
Design Parameters ◽  
Wear Analysis ◽  
Lock In

The finger lock in the retractable actuator of the landing gear will wear during repeated unlocking and locking. Therefore, the effects of six parameters including the material of the finger lock, the length of the finger lock, the diameter of the finger lock, the number of petals, and the angle of the fingertip on the unlocking force after 500 unlocking cycles are researched. Archard wear theory was performed to obtain the unlocking force after wear and the influence of six key parameters on the unlocking force in this paper. Then, wear experiment was designed and the effectiveness of model and the influence of six parameters were verified. The results show that the chamfers of the finger lock was most worn, causing the value of the axial unlocking force during the transition phase to increase, but it has little effect on the maximum unlocking axial force. The material of the lock has little effect on the axial force; the length, diameter and the number of petals are inversely proportional to the axial force, and the angle of the fingertip is proportional to the axial force. Using Archard method can effectively calculate the finger pattern wear of locks.

A SEM and Light Microscope Study of the Epidermal Leaf Structures of the Carnivorous Plant, Sarracenia purpurea, L.

1971 ◽  
Vol 29 ◽  
pp. 358-359
Author(s):  
B. J. Panessa ◽  
J. F. Gennaro
Keyword(s):  
Methylene Blue ◽  
Toluidine Blue ◽  
Outer Surface ◽  
Microscope Study ◽  
Light Microscope ◽  
Carnivorous Plant ◽  
Sarracenia Purpurea ◽  
Inner Surface

Tissue from the hood and sarcophagus regions were fixed in 6% glutaraldehyde in 1 M.cacodylate buffer and washed in buffer. Tissue for SEM was partially dried, attached to aluminium targets with silver conducting paint, carbon-gold coated(100-500Å), and examined in a Kent Cambridge Stereoscan S4. Tissue for the light microscope was post fixed in 1% aqueous OsO4, dehydrated in acetone (4°C), embedded in Epon 812 and sectioned at ½u on a Sorvall MT 2 ultramicrotome. Cross and longitudinal sections were cut and stained with PAS, 0.5% toluidine blue and 1% azure II-methylene blue. Measurements were made from both SEM and Light micrographs.The tissue had two structurally distinct surfaces, an outer surface with small (225-500 µ) pubescent hairs (12/mm2), numerous stoma (77/mm2), and nectar glands(8/mm2); and an inner surface with large (784-1000 µ)stiff hairs(4/mm2), fewer stoma (46/mm2) and larger, more complex glands(16/mm2), presumably of a digestive nature.

Gastric Ulcers Produced by Cisplatin

1981 ◽  
Vol 39 ◽  
pp. 582-583
Author(s):  
S.K. Aggarwal ◽  
J. San Antonio
Keyword(s):  
Electron Microscopy ◽  
Single Dose ◽  
Side Effects ◽  
Antitumor Agent ◽  
Gastric Ulcers ◽  
Enzyme Cytochemistry ◽  
Intestinal Toxicity ◽  
Ovarian Cancers ◽  
Inner Surface

Cisplatin (cis-dichlorodiammineplatinum(II)) a potent antitumor agent is now available for the treatment of testicular and ovarian cancers. It is however, not free from its serious side effects including nephrotoxicity, gastro intestinal toxicity, myelosuppression, and ototoxicity. Here we now report that the drug produces peculiar bloating of the stomach in rats and induces acute ulceration.Wistar-derived rats weighing 200-250 g were administered cisplatin(9 mg/kg) ip as a single dose in 0.15 M NaCl. After 3 days the animals were sacrificed by decapitation. The stomachs were removed, the contents analyzed for pepsin and acidity. The inner surface was examined with a dissecting microscope after a moderate stretching for ulcers. Affected areas were fixed and processed for routine electron microscopy and enzyme cytochemistry.The drug treated animals kept on food and water consistently showed bloating and lesions (Fig. 1) with a frequency of 6-70 ulcers in the rumen section of the stomachs.

Mechanical characteristics of the EGJ after fundoplication compared to normal subjects and GERD patients

2001 ◽  
Vol 120 (5) ◽  
pp. A112-A112 ◽  
Author(s):  
J CURRY ◽  
G SHI ◽  
J PANDOLFINO ◽  
R JOEHL ◽  
J BRASSEUR ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Normal Subjects

Amplitude-Modulated Lock-In Vibrothermography for NDE of Polymers and Composites

1995 ◽  
Vol 7 (1) ◽  
pp. 215-228 ◽  
Author(s):  
J. Rantala ◽  
D. Wu ◽  
G. Busse
Keyword(s):  
Lock In
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