scholarly journals ЗАКОН РАСПРЕДЕЛЕНИЯ РАЗРУШАЮЩИХ НАГРУЗОК ЭЛЕМЕНТОВ КАРКАСА КУПОЛА ПАРАШЮТА

2019 ◽  
pp. 73-79
Author(s):  
Петр Александрович Фомичев ◽  
Игорь Михайлович Сила
Keyword(s):  
Normal Distribution ◽  
Breaking Load ◽  
Strength Characteristics ◽  
Safety Factors ◽  
Significant Deterioration ◽  
Extreme Loads ◽  
Long Term Storage ◽  
The Moment ◽  
Term Storage

It is known that during operation or long-term storage, there is a significant deterioration (degradation) of the strength characteristics of the strength elements of the parachute canopy’s carcase, including shroud lines, canopy’s fabric, reinforcement tapes, free ends of the suspension system, leg straps, etc.Parachutes are designed considering the specific safety factors of power elements for the extreme loads resistance at the moment of parachute opening. Further operation after the specified period with unchanged safety factors is possible only in flight conditions limitation, in particular, landing speeds. Strength characteristics are characterized by significant scattering. The design of parachutes is carried out considering the guaranteed values of destructive loads of elements with a given level of reliability. In this case, the law of destructive loads distribution must be known.It was tested the normal distribution applicability of the strength characteristics applying the compound compliance criterion. The basis is the data of strength tests until the destruction of shroud lines samples and fabric of the canopy warpwise and wefting. The samples were cut from D-5 series 2 parachute of the year 1983, Z-5 reserve parachute of 1984, the rescue parachute C-5 K series 2 of the 1989. It was tested totally 301 samples of various materials from these parachutes. At the first stage of processing the test data, by experimental determination of the breaking load, the gross emissions were rejected, then a composite criterion for compliance with the normal law was applied.According to the results of comparison with experimental data, the validity of the normal distribution of destructive loads for the shroud lines and canopy’s fabrics both warpwise and wefting is unambiguously shown. The obtained result makes it possible to evaluate the strength characteristics of the carcase elements after operation or long-term storage with the required level of reliability and, in the future, to find the strength degradation factors of the power elements. These factors will limit the maximum allowed landing speed with a specific parachute.

Експериментальне визначення стану текстильних матеріалів десантної парашутної системи Д-5 серії 2 після тривалого зберігання. Повідомлення 1. Фактичний стан міцності текстильних матеріалів основного парашуту

2021 ◽  
pp. 4-11
Author(s):  
Ігор Михайлович Сила
Keyword(s):  
Mechanical Characteristics ◽  
Breaking Load ◽  
Strength Characteristics ◽  
Safety Factors ◽  
Textile Materials ◽  
Long Term Storage ◽  
Parachute System ◽  
Parachute Canopy ◽  
Term Storage

The subject matter of the article is a comparative analysis of indicators of strength and elasticity of textile materials of the main parachute canopy before and after long-term storage. A simplified approach proposed by N. A. Lobanov and P.O. Fomichov was used, the coefficients of degradation of the strength characteristics of the textile materials of the main parachute of the D-5 landing parachute system of series 2 after its long-term storage were experimentally determined. These coefficients are defined as the ratio of the strength characteristics of individual elements of the parachute system in the design sections after the operation or long-term storage to their initial value adopted in the design of the parachute. The goal is to obtain an array of data to assess the state of the physical and mechanical characteristics of the main parachute materials. It is known that in the process of long-term storage there is a deterioration (degradation) of the strength characteristics of the strongest elements of the frame of the parachute canopy, lines, canopy fabrics, reinforcing tapes, etc. Further operation beyond the established period while maintaining sufficient safety factors is possible only with the availability of modern data. Tasks: to develop and test a method of sampling materials, experimentally determine the characteristics of materials, choose an effective algorithm for calculating safety factors. The following methods and equipment were used. The actual value of the indicators was established by destructive strength measurements. The methodology for preparing test samples of D-5 series 2 landing parachute systems, taking point and elementary samples of textile materials of individual elements of the parachute system in design sections for laboratory research to determine mechanical characteristics (strength, elongation, and air permeability) has been improved. The tearing machine is equipped with specialized clamping devices. The batch size was 25 parachute systems. The breaking load and the relative elongation were measured for slings and braids, for fabric - along the warp and weft, a total of 1250 elementary samples. Degradation coefficients were calculated. The array of empirical data was processed by mathematical and statistical methods of the Descriptive Statistics software package from the add-in of the MS EXCEL Analysis Package. The following results were obtained. In terms of breaking load, the fabric of the main parachute canopy slightly (up to 3 percent) exceeds the standard value. The elastic characteristics of the fabric fully meet the requirements - exceeding 1 ÷ 4 percent. During storage, the slings of the main parachute lost up to 21% in strength, but at the same time retained their elastic properties - exceeding up to 3 times. The tapes have satisfactory strength characteristics (exceeding from 3 to 12 percent), in terms of elongation at break, they have lost from 15 to 25 percent. Conclusions. The novelty of the results obtained is as follows: for the first time, the strength characteristics were measured and evaluated in the design sections of the fabric, reinforcing tapes of the power frame of the canopy and lines of the main parachute of the D-5 landing parachute system of series 2 on a large sample of 25 parachutes; it is shown that the obtained data will be correct for all parachute systems produced in 1973-1974.

scholarly journals Vitrification of particulated articular cartilage via calculated protocols

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kezhou Wu ◽  
Nadia Shardt ◽  
Leila Laouar ◽  
Janet A. W. Elliott ◽  
Nadr M. Jomha
Keyword(s):  
Articular Cartilage ◽  
Cartilage Defects ◽  
Human Articular Cartilage ◽  
Significant Deterioration ◽  
Chondrocyte Viability ◽  
Long Term Storage ◽  
Graft Tissue ◽  
Articular Cartilage Defects ◽  
Term Storage

AbstractPreserving viable articular cartilage is a promising approach to address the shortage of graft tissue and enable the clinical repair of articular cartilage defects in articulating joints, such as the knee, ankle, and hip. In this study, we developed two 2-step, dual-temperature, multicryoprotectant loading protocols to cryopreserve particulated articular cartilage (cubes ~1 mm3 in size) using a mathematical approach, and we experimentally measured chondrocyte viability, metabolic activity, cell migration, and matrix productivity after implementing the designed loading protocols, vitrification, and warming. We demonstrated that porcine and human articular cartilage cubes can be successfully vitrified and rewarmed, maintaining high cell viability and excellent cellular function. The vitrified particulated articular cartilage was stored for a period of 6 months with no significant deterioration in chondrocyte viability and functionality. Our approach enables high-quality long-term storage of viable articular cartilage that can alleviate the shortage of grafts for use in clinically repairing articular cartilage defects.

Modelling of Moisture Movement in Wood during Outdoor Storage

2001 ◽  
Vol 6 (2) ◽  
pp. 3-14 ◽  
Author(s):  
R. Baronas ◽  
F. Ivanauskas ◽  
I. Juodeikienė ◽  
A. Kajalavičius
Keyword(s):  
Experimental Data ◽  
Finite Difference ◽  
Climatic Conditions ◽  
Two Dimensional ◽  
Moisture Movement ◽  
Finite Difference Technique ◽  
Long Term Storage ◽  
Space Formulation ◽  
Term Storage

A model of moisture movement in wood is presented in this paper in a two-dimensional-in-space formulation. The finite-difference technique has been used in order to obtain the solution of the problem. The model was applied to predict the moisture content in sawn boards from pine during long term storage under outdoor climatic conditions. The satisfactory agreement between the numerical solution and experimental data was obtained.

Trehalose: a cryoprotectant that enhances recovery and preserves function of human pancreatic islets after long-term storage

Diabetes ◽  
1997 ◽  
Vol 46 (3) ◽  
pp. 519-523 ◽  
Author(s):  
G. M. Beattie ◽  
J. H. Crowe ◽  
A. D. Lopez ◽  
V. Cirulli ◽  
C. Ricordi ◽  
...  
Keyword(s):  
Pancreatic Islets ◽  
Human Pancreatic Islets ◽  
Long Term Storage ◽  
Term Storage

Humidity reliability of commercial flash memories for long-term storage

2020 ◽  
Vol 59 (SL) ◽  
pp. SLLC01 ◽  
Author(s):  
Tomoki Murota ◽  
Toshiki Mimura ◽  
Ploybussara Gomasang ◽  
Shinji Yokogawa ◽  
Kazuyoshi Ueno
Keyword(s):  
Flash Memories ◽  
Long Term Storage ◽  
Term Storage

MODERN PROBLEMATICS AND ANALYSIS OF EFFICIENCY OF APPLICATION OF DIFFERENT APPROACHES TO DESTRUCTION OF INFORMATION ON MAGNETIC MEDIA

2019 ◽  
Vol 2 (12) ◽  
pp. 154-164
Author(s):  
O. Semenenko ◽  
O. Vodchyts ◽  
V. Koverga ◽  
R. Lukash ◽  
O. Lutsenko
Keyword(s):  
Armed Forces ◽  
Information Storage ◽  
Storage Device ◽  
Magnetic Media ◽  
Long Term Storage ◽  
Physical Impact ◽  
And Storage ◽  
Term Storage

The introduction and active use of information transmission and storage systems in the Ministry of Defense (MoD) of Ukraine form the need to develop ways of guaranteed removal of data from media after their use or long-term storage. Such a task is an essential component of the functioning of any information security system. The article analyzes the problems of guaranteed destruction of information on magnetic media. An overview of approaches to the guaranteed destruction of information on magnetic media of different types is presented, and partial estimates of the effectiveness of their application are given by some generally accepted indicators of performance evaluation. The article also describes the classification of methods of destruction of information depending on the influence on its medium. The results of the analysis revealed the main problems of application of software methods and methods of demagnetization of the information carrier. The issue of guaranteed destruction of information from modern SSD devices, which are actively used in the formation of new systems of information accumulation and processing, became particularly relevant in the article. In today's conditions of development of the Armed Forces of Ukraine, methods of mechanical and thermal destruction are more commonly used today. In the medium term, the vector of the use of information elimination methods will change towards the methods of physical impact by the pulsed magnetic field and the software methods that allow to store the information storage device, but this today requires specialists to develop new ways of protecting information in order to avoid its leakage.

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