Impact of Alkali-Silica Reaction ASR on Structural Integrity of Light-Weight Wellbore Cement

2017 ◽  
Author(s):  
Dylan Albers
Keyword(s):  
Structural Integrity ◽  
Alkali Silica Reaction ◽  
Light Weight

Optimization of a Light-Weight Composite Blast Containment Vessel Structural Response

2007 ◽  
Author(s):  
Jagadeep Thota ◽  
Ashok K. Ayyaswamy ◽  
Mohamed B. Trabia ◽  
Brendan J. O’Toole
Keyword(s):  
Structural Integrity ◽  
Optimization Technique ◽  
Structural Response ◽  
Optimization Procedure ◽  
Element Model ◽  
Light Weight ◽  
Gusset Plates ◽  
Containment Vessel ◽  
Plastic Composite ◽  
Design Variables

This paper proposes an optimization technique for increasing the structural integrity of a light-weight composite blast containment vessel. The vessel is cylindrical with two hemispherical ends. It has a steel liner that is internally reinforced with throttles and gusset plates and wrapped with a basalt-plastic composite. A finite element model of the blast containment vessel was proposed and verified in an earlier work. The parameters of the vessel are incorporated within an iterative optimization procedure to decrease the peak strains within the vessel, which are caused by internal blast loading due to an explosive charge placed at the center of the vessel. The procedure is validated for different initial guesses of the design variables.

scholarly journals An Optimized Prefabricated Raft Footing System for Houses on Shrink-Swell Soils: Preliminary Results

2019 ◽  
pp. 59-66 ◽  
Author(s):  
Bertrand Teodosio ◽  
Kasun Shanaka ◽  
Kristombu Baduge ◽  
Priyan Mendis
Keyword(s):  
Soil Moisture ◽  
Structural Integrity ◽  
Skilled Labor ◽  
Manual Labor ◽  
Light Weight ◽  
Severe Damage ◽  
Construction Period ◽  
Ground Movements ◽  
Prefabricated Houses ◽  
Site Disturbance

The strong demand for houses has been hampered by a shortage of skilled labor in Australia, which can be potentially alleviated using prefabrication. Significant advancements in the design and construction of prefabricated houses have been observed; however, most substructure constructions still use traditional cast-in-place method that is labor intensive and weather-dependent. Prefabrication of footing systems is an advantageous solution since this require minimal manual labor and shorter construction period. The design of an innovative prefabricated footing needs to consider structural integrity and design assembly. One of the important structural issues for light-weight houses is cyclic differential ground movements affecting footing systems due to reactive soils. This shrink-swell movements are due to the decrease and increase in soil moisture, which can cause minor to severe damage depending on the presence of fines. Due to the issues on shortage of skilled labor and housing, and the costly impact of shrink-swell movements of reactive soils to footings, this study aims to develop a prefabricated footing based on optimized waffle raft. The developed system can easily be installed in stable to highly reactive sites, minimizing site disturbance, on-site assembly requirements and maximizing construction speed, quality and sustainability.

Structural Response Optimization of a Light-Weight Composite Blast Containment Vessel

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Jagadeep Thota ◽  
Mohamed B. Trabia ◽  
Brendan J. O’Toole ◽  
Ashok K. Ayyaswamy
Keyword(s):  
Structural Integrity ◽  
Optimization Technique ◽  
Structural Response ◽  
Optimization Procedure ◽  
Element Model ◽  
Light Weight ◽  
Computationally Efficient ◽  
Containment Vessel ◽  
Plastic Composite ◽  
Design Variables

This paper proposes an optimization technique for increasing the structural integrity of a light-weight composite blast containment vessel. The vessel is cylindrical with two hemispherical ends. It has a steel liner that is internally reinforced with throttles and gusset plates and wrapped with a basalt-plastic composite. A computationally-efficient finite element model of the blast containment vessel was proposed and verified in an earlier work. The parameters of the vessel are incorporated within an iterative optimization procedure to decrease the peak strains within the vessel, which are caused by internal blast loading due to an explosive charge placed at the center of the vessel. The results of the proposed procedure are validated for different initial guesses of the design variables.

Structural Integrity Monitoring of Composite Pipes

2007 ◽  
Vol 347 ◽  
pp. 615-620 ◽  
Author(s):  
Nicolae Constantin ◽  
Alexandrina Mihai ◽  
Mircea Găvan ◽  
Ştefan Sorohan ◽  
Constantin Dumitraşcu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Composite Materials ◽  
Structural Integrity ◽  
Service Reliability ◽  
Light Weight ◽  
Wave Method ◽  
Steel Pipes ◽  
Composite Pipes ◽  
Non Destructive ◽  
Made In

Composite pipes enjoy increasing interest in the sector of petroleum and gas transportation, due to a number of qualities, concerning especially the corrosion resistance and light weight, face to the traditional steel pipes. As composite materials are prone to a various range of defects and damages which can seriously affect their service ability, reliable inspection methods have to be tested in order to assure the required in service reliability. The paper presents progress made in applying complementary global/local non-destructive inspection (NDI) methods, such as Lamb wave method and infrared thermography (IRT) method, to effective structural health (SHM) monitoring of composite pipes.

Evaluation of the expansion attained to date by concrete affected by alkali–silica reaction. Part I: Experimental study

2004 ◽  
Vol 31 (5) ◽  
pp. 826-845 ◽  
Author(s):  
Nizar Smaoui ◽  
Marc-André Bérubé ◽  
Benoit Fournier ◽  
Benoit Bissonnette ◽  
Benoit Durand
Keyword(s):  
Structural Integrity ◽  
Test Method ◽  
Alkali Silica Reaction ◽  
Test Surface ◽  
Surface Cracking ◽  
Concrete Cylinders ◽  
Width Measurements ◽  
American Society ◽  
Concrete Prism Test ◽  
Crucial Parameter

The expansion to date of the concrete from a structure affected by alkali–silica reaction (ASR) is a crucial parameter in the evaluation of the structural integrity of the structure. Three methods have been used to evaluate this expansion: (i) the "stiffness damage test" (SDT), (ii) the "damage rating index" (DRI), and (iii) surface cracking. Concrete cylinders were made using several types of coarse and fine reactive aggregates and subjected to the Canadian Standards Association (CSA) concrete prism test CSA A23.2-14A (or American Society for Testing and Materials (ASTM) test method C1293), i.e., at 38 °C and >95% relative humidity (RH). At various expansion levels, the specimens were subjected to SDT and DRI tests. Very good relationships were obtained between the expansion due to ASR and the SDT. The correlation between the ASR expansion and the DRI was not as good but still of interest. Width measurements of surface cracks were also performed on a number of blocks made with different reactive aggregates and exposed in the laboratory at 38 °C and >95% RH. The expansion estimated from these measurements was much lower than that measured on the blocks.Key words: aggregates, alkali–silica reaction, concrete expansion, damage rating index, petrography, stiffness damage test, surface cracking.

Carbon Fiber Composites: A Solution for Light Weight Dynamic Components of AFVs

2017 ◽  
Vol 67 (4) ◽  
pp. 420 ◽  
Author(s):  
Subodh Kumar Nirala ◽  
Sarath Shankar ◽  
Dhanalakshmi Sathishkumar ◽  
V. Kavivalluvan ◽  
P. Sivakumar
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Structural Integrity ◽  
Traditional Approach ◽  
Load Test ◽  
Carbon Fiber Composites ◽  
Light Weight ◽  
Static Load Test ◽  
Element Analysis ◽  
Specific Strength

<p class="p1">Changing circumstances across the world require armored fighting vehicle (AFV) of a country to be more agile, easily manoeuverable and transportable besides other key requirements like firepower and protection. Therefore, the AFV should be as light as possible. The use of conventional materials and techniques do not fulfill the requirement of light weight AFV. The composite materials having high specific modulus, specific strength and directional properties are the alternative substitution for reducing the weight. A customized design approach with proper selection of composite material is essential to make AFV components with required properties at lower weight as compared to the traditional approach. Special properties like resistance to moisture, solvents, UV degradation etc. could be imparted to the composite components by the use of proper additives or fillers. This paper deals with the development of dynamic members like road wheel, top roller and axle arm, whose count is always more in any AFVs, using carbon-epoxy composite material. The details of composite materials used and the manufacturing processes adopted are briefly discussed. The static load test carried out to assess the structural integrity as well as non-destructive tests (NDT) performed to detect the defects are also dealt in detail. Preliminary Finite Element Analysis and Multi-body Dynamic Analysis have also been discussed. These analyses have been done mainly to understand the sustainability and performance of the components developed under the given loading conditions.</p>

Prevention of Alkali-Silica Reaction (ASR) in Light-Weight Wellbore Cement Comprising Silicate-Based Microspheres

2017 ◽  
Author(s):  
Dylan Albers ◽  
Mileva Radonjic
Keyword(s):  
Alkali Silica Reaction ◽  
Lithium Nitrate ◽  
Light Weight ◽  
Lost Circulation ◽  
Chemical Instability ◽  
Alkali Silica Reactivity ◽  
High Alkalinity ◽  
Hydrophilic Gel ◽  
Micro Indentation ◽  
Scanning Electron

Drilling through low pressure formations, either offshore or through depleted formations, requires the use of low density fluids to prevent lost circulation and as well as to properly place cement during cementing applications. Achieving these densities in cements can be done through foaming the cement, increasing water content, or through the addition of silica based microspheres. Each of these methods have individual limitations, and in the case of silica based microspheres, their specific fallback is a chemical instability with the microsphere itself reacting with the cement pore fluid. This chemical instability creates a hydrophilic gel that is expansive and creates fractures in the cement as it expands, which is more formally referred to as alkali-silica reactivity (ASR). Prevention of ASR involves the application of additives to the cement that acts as a sink for the alkalinity in which prevents the expansion of ASR. A specific application that this paper investigates for this prevention is the use of Lithium nitrate. This study looks at the effects of a high alkalinity environment onto the microspheres by visualizing the reactions that are occurring using Scanning Electron Microscopy (SEM), and confirming the presence of ASR when silica based microspheres encounter a high pH environment. Then cement samples were created to compare the effects lithium nitrate has on cements created with silica based microspheres. SEM and micro indentation was conducted on these samples, which showed that lithium nitrate prevents reactions, but after 28-day hydration a loss of mechanical properties is present.

Electron Beam Damage of Biomolecules Assessed by Energy Loss Spectroscopy

1978 ◽  
Vol 36 (3) ◽  
pp. 61-69
Author(s):  
M. Isaacson ◽  
M.L. Collins ◽  
M. Listvan
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Structural Integrity ◽  
Analytical Electron Microscopy ◽  
High Dose ◽  
Dose Rates ◽  
Special Cases ◽  
Analytical Electron ◽  
Atom Migration ◽  
Beam Damage

Over the past five years it has become evident that radiation damage provides the fundamental limit to the study of blomolecular structure by electron microscopy. In some special cases structural determinations at very low doses can be achieved through superposition techniques to study periodic (Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977) specimens. In addition, protection methods such as glucose embedding (Unwin & Henderson, 1975) and maintenance of specimen hydration at low temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite these successes, the basic nature of radiation damage in the electron microscope is far from clear. In general we cannot predict exactly how different structures will behave during electron Irradiation at high dose rates. Moreover, with the rapid rise of analytical electron microscopy over the last few years, nvicroscopists are becoming concerned with questions of compositional as well as structural integrity. It is important to measure changes in elemental composition arising from atom migration in or loss from the specimen as a result of electron bombardment.

Microstructure of an extruded rapidly solidified Al-8Fe-2Mo alloy

1986 ◽  
Vol 44 ◽  
pp. 548-549
Author(s):  
W. T. Donlon ◽  
J. E. Allison ◽  
S. Shinozaki
Keyword(s):  
Electron Microscopy ◽  
Automotive Industry ◽  
Fuel Economy ◽  
High Strength ◽  
Al Alloys ◽  
Light Weight ◽  
Thin Sections ◽  
Strength And Durability ◽  
Rapidly Solidified ◽  
Whitney Aircraft

Light weight materials which possess high strength and durability are being utilized by the automotive industry to increase fuel economy. Rapidly solidified (RS) Al alloys are currently being extensively studied for this purpose. In this investigation the microstructure of an extruded Al-8Fe-2Mo alloy, produced by Pratt & Whitney Aircraft, Goverment Products Div. was examined in a JE0L 2000FX AEM. Both electropolished thin sections, and extraction replicas were examined to characterize this material. The consolidation procedure for producing this material included a 9:1 extrusion at 340°C followed by a 16:1 extrusion at 400°C, utilizing RS powders which have also been characterized utilizing electron microscopy.

Structural integrity after cold storage of human epidermal model in hypothermosol: A correlative ultrastructural and fluorescent assay

1994 ◽  
Vol 52 ◽  
pp. 270-271
Author(s):  
Henry H. Eichelberger ◽  
John G. Baust ◽  
Robert G. Van Buskirk
Keyword(s):  
Cold Storage ◽  
Structural Integrity ◽  
Culture Media ◽  
Cell Structure ◽  
Natural State ◽  
Sodium Cacodylate ◽  
Ruthenium Tetroxide ◽  
Cacodylate Buffer ◽  
Before And After

For research in cell differentiation and in vitro toxicology it is essential to provide a natural state of cell structure as a benchmark for interpreting results. Hypothermosol (Cryomedical Sciences, Rockville, MD) has proven useful in insuring the viability of synthetic human epidermis during cold-storage and in maintaining the epidermis’ ability to continue to differentiate following warming.Human epidermal equivalent, EpiDerm (MatTek Corporation, Ashland, MA) consisting of fully differentiated stratified human epidermal cells were grown on a microporous membrane. EpiDerm samples were fixed before and after cold-storage (4°C) for 5 days in Hypothermosol or skin culture media (MatTek Corporation) and allowed to recover for 7 days at 37°C. EpiDerm samples were fixed 1 hour in 2.5% glutaraldehyde in sodium cacodylate buffer (pH 7.2). A secondary fixation with 0.2% ruthenium tetroxide (Polysciences, Inc., Warrington, PA) in sodium cacodylate was carried out for 3 hours at 4°C. Other samples were similarly fixed, but with 1% Osmium tetroxide in place of ruthenium tetroxide. Samples were dehydrated through a graded acetone series, infiltrated with Spurrs resin (Polysciences Inc.) and polymerized at 70°C.

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