The effect of long‐time moisture exposure and low temperatures on mechanical behavior of open‐hole Cfrp laminate

2021 ◽  
Author(s):  
Vladimír Mára ◽  
Lenka Michalcová ◽  
Martin Kadlec ◽  
Jan Krčil ◽  
Petr Špatenka
Keyword(s):  
Mechanical Behavior ◽  
Low Temperatures ◽  
Cfrp Laminate ◽  
Open Hole ◽  
Long Time

Oxidation Behavior of Amorphous Nano-Si3N4 Powders

2014 ◽  
Vol 602-603 ◽  
pp. 367-370 ◽  
Author(s):  
Jiang Bo Wen ◽  
Sheng Huang ◽  
Hong Jie Wang
Keyword(s):  
High Temperature ◽  
Partial Pressure ◽  
Mechanical Behavior ◽  
Low Temperatures ◽  
Traditional Method ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Composite Ceramic ◽  
Intergranular Phase ◽  
Sintering Additives

The traditional method preparing Si3N4/Si2N2O composite ceramic is to sinter α-Si3N4 powder with additives at relatively high temperatures. But the intergranular phase transformed from the sintering additives can degrade the high-temperature mechanical behavior. Amorphous nanoSi3N4 is used to fabricate Si3N4/Si2N2O composite ceramic by its oxidation and nitridation without sintering additives at low temperatures. Thus, it is essential to study the oxidation behavior and mechanism of amorphous nanoSi3N4. Amorphous nanoSi3N4 powders were oxidized in different atmospheres, at varying temperatures and for various different length of time. The oxidation process and products was analyzed by means of XRD, TGA and FTIR. The results showed that amorphous nanoSi3N4 could be oxidized into SiO2 from 600°C to 1300°C. Below 1300°C, the oxidation became serious as the temperature increased. Besides, the longer the oxidation time and the lager the ratio of O2/N2 partial pressure was, the deeper the oxidation level was. When the temperature was above 1300°C, amorphous nanoSi3N4 was completely oxidized into SiO2.

scholarly journals Quality Oil for Deep Frying in Foods and Changes Acidity on Various Kind of Oils after Frying

2018 ◽  
Vol 2 (3) ◽  
pp. 86
Author(s):  
Puminat W. ◽  
Teangpook C.
Keyword(s):  
Fatty Acid ◽  
Low Temperatures ◽  
Statistical Data ◽  
Rice Bran Oil ◽  
Acid Value ◽  
Deep Frying ◽  
Significant Difference ◽  
Long Time ◽  
Short Time ◽  
Fried Oil

<p><em>Human eat a lot of highly acidic and oxidant foods. Acid chemicals and oxidants in food cause harmful to the health. Acid value, free fatty acid and polarities of the fried oil change during cooking for food. Statistical data of fried oils estimate and systematize on three recipes of food (</em><em>Doughstick</em><em>, Fish cake and Fried chicken). Their recipes are on the best of sensory evaluation.</em><em> In each food recipes are selected from market and evaluated by traditional and popular merchant. In the sampling, the experimental model is planned by trial RBCD with factorial 3 × 2 × 3. The use of three type oil, two level temperature and three sampling collector are treated on experiments with three recipes. They showed that palm olien oil can change a higher pH than soybean oil and rice bran oil by a statistically significant difference at 95% confidence level<strong>.</strong> Deep frying by high temperatures and short time have change a quality oil less than low temperatures and long time. Frying in larger quantities and a longer period can change the more acidity and polarities. Quality foods for flavor and healthy oil must no more high and low temperature in cooking.</em></p>

scholarly journals The effect of loading frequency on the cyclic mechanical behavior of polyethylene

2015 ◽  
Vol 18 (4) ◽  
pp. 162-169
Author(s):  
Thao Song Thanh Nguyen ◽  
Nhung Thi Tuyet Le
Keyword(s):  
Experimental Investigation ◽  
Mechanical Behavior ◽  
Hysteresis Loop ◽  
Room Temperature ◽  
Tensile Tests ◽  
Loading Frequency ◽  
Ratcheting Strain ◽  
Accumulated Strain ◽  
Long Time ◽  
Kinetics Of

An experimental investigation into ratcheting strain and stress-strain hysteresis loop in stress-controlled cyclic tensile tests at room temperature was performed to determine the effect of loading frequency on the cyclic mechanical behavior of highdensity polyethylene (HDPE). It was found that frequencies ranging from 0.01 Hz up to 1 Hz mostly affects the accumulated strain over related time scales (i.e that of the cycle itself) and not over long time scale (i.e. during the full test). In addition, the higher the frequency is, the more closed and vertical the loops are. Furthermore, the frequency affects only on the kinetics of stabilization of ratcheting strain but not on one of hysteresis loop.

Considerations in Low-Temperature Mechanical Behavior of Polymer Composite Materials

2015 ◽  
Vol 760 ◽  
pp. 323-328
Author(s):  
Stefan Cotae ◽  
Constantin Popescu ◽  
Horatiu Iancau
Keyword(s):  
Tensile Strength ◽  
Mechanical Behavior ◽  
Fiber Orientation ◽  
Low Temperatures ◽  
Composite Structures ◽  
Room Temperature ◽  
Experimental Program ◽  
Independent Variables ◽  
Factorial Method ◽  
Degree Of Reinforcement

In this paper it has been sought to highlight the mechanical behavior of composite structures at low temperatures compared to mechanical behavior at room temperature. For researches an experimental program has been conceived and built using factorial method. In this method, as dependent variable was taken the tensile strength (σr), while as independent variables were taken: the fiber orientation angles (θ), the degree of reinforcement (Mf) of the composite structure and the temperature (t) at which the tests were carried out (+25°C,-25°C and-50°C respectively). It has been used a complex experimental installation, specific to tests at low temperatures.

Dislocation Core Structures and Mechanical Behavior of DO22 Type Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
M. Khantha ◽  
V. Vitek ◽  
D.P. Pope
Keyword(s):  
Mechanical Behavior ◽  
Low Temperatures ◽  
Dislocation Core ◽  
Intermetallic Alloy ◽  
Tetragonal Distortion ◽  
The Core ◽  
External Stresses

ABSTRACTWe investigate the structures of dislocation cores in a model DO22 type intermetallic alloy in the absence of external stresses. The tetragonal distortion produces sessile configurations of superpartial dislocations even when the energies of planar faults are reasonably low. The influence of the core configurations on the mechanical behavior at low temperatures is discussed.

scholarly journals Hydrocolloid effect on the stabilization of vegetable purees in the process of freezing, refrigerating and defrosting

2018 ◽  
Vol 6 (2) ◽  
pp. 325-333
Author(s):  
Albert Nugmanov ◽  
Albert Nugmanov ◽  
Panagiotis Hadjisimu ◽  
Panagiotis Hadjisimu ◽  
Lyubov Titova ◽  
...  
Keyword(s):  
Cold Storage ◽  
Low Temperatures ◽  
Xanthan Gum ◽  
Plant Origin ◽  
Initial Product ◽  
Organoleptic Characteristics ◽  
Long Time ◽  
Weak Expression ◽  
The Individual ◽  
Synergistic Combinations

The analysis of modern concepts of the use of hydrocolloids for the stabilization of mashed products of plant origin in the freezing – storage – defrosting circle is given. The effect of hydrocolloids on the structure of vegetable purees using the example of xanthan gum, starch and inulin was studied. The most significant characteristics of the structure was identified and their descriptors were considered. Experimental data on the effect of hydrocolloids on the microstructure of vegetable purees was obtained. The expediency of using starch and xanthan gum in combination with inulin was shown. To create a viscous structure, modified starch with small granules that exhibit thermal stability in cold storage and further heat treatment were most suitable. Inulin was also not subject to changes during temperature treatments for the products with a pH higher than 3.5, but probably would not be widely used as a structurant for vegetable purees due to the weak expression of the structure-forming properties. The synergistic combinations of inulin and xanthan gum improved the organoleptic characteristics of the product, especially in cold storage. In addition, the ability of inulin to form a smooth structure in vegetable purée when enveloping the oral cavity was revealed, despite the fact that the initial product had a rather coarse fibrous consistency due to the plant origin of the ingredients. Thus, it is promising to use inulin in combination with thickeners to give the product prebiotic properties with the improved perception in consumers. The results of the studies confirm the possibility of storing vegetable purees at low temperatures for a long time without the deterioration of the structural and organoleptic properties resulting from the slowly occurring degradation processes of the individual components of the product at low temperatures, provided that the hydrocolloids under study are used.

Unconventional Drilling and Creative Solutions Delivered World Record a Multi-Laterals Fishbone all Legs Drilled, Accessed and Stimulated First Attempt - Case Study from Kuwait

2021 ◽  
Author(s):  
Nadir Farhi ◽  
Mohamed Ahmed Abdel Samie ◽  
Walid Saher Nouh ◽  
Hamdi Saber Ibrahim ◽  
Hadi Saad Al-Ajmi ◽  
...  
Keyword(s):  
Lessons Learned ◽  
Horizontal Drilling ◽  
Execution Phase ◽  
Multi Stage ◽  
Major Development ◽  
Creative Solutions ◽  
Tight Carbonate ◽  
Study Team ◽  
Open Hole ◽  
Long Time

Abstract Despite being the first area for oil to be found in Kuwait in mid 1930's, Bahra's oil production remained largely unexploited until 2015, when a major development campaign targeting one of its tight carbonate reservoirs through horizontal drilling and multi-stage frack completions was commissioned. Nonetheless, with the development and exploration initiatives underway, surface congestion is the primary challenge. As the number of wells increased the need for unconventional well profiles became more demanding. The multi-lateral fishbone approach was designed to have a total of four laterals with approximately 3000 ft each. Lessons learned from previous level-1 multi-laterals drilled in North Kuwait indicated that the primary challenge remained to be the ability to drill a smooth bore hole profile across the junctions to successfully re-access and stimulate all the drilled legs with coil-tubing to maximize production. Kuwaiti Operator Reservoir and study team were looking for an alternate solution to increase the production in Bahra using multi-laterals technics in the same reservoir to stimulate and sustain production in calcite reservoir. Historically only three wells were drilled experimenting challenges and failures to open hole sidetrack leading to have long time to complete the wells with maximum 3 legs as record including the mother hole. RST team asked to drill a well with 4 legs, each leg following the same azimuth with the condition to be 300 ft apart. The thorough planning exercise completed and the close follow-up to the approved design of service during execution phase resulted in the successful delivery of the first four legs fishbone in Kuwait with Zero Non-Productive Time. In addition to achieving all the geological targets, the smooth borehole profile helped ensure successful re-entry and stimulation of all four legs in the same run achieving the well challenge using the unique

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