scholarly journals Chemical Durability of Glass Containing Srp Waste - Leachability Characteristics, Protective Layer Formation, and Repository System Interactions

1981 ◽  
Vol 11 ◽  
Author(s):  
George G. Wicks ◽  
Barbara M. Robnett ◽  
W. Duncan Rankin
Keyword(s):  
Protective Layer ◽  
Layer Formation ◽  
Surface Layers ◽  
Waste Products ◽  
Safety And Reliability ◽  
Experimental Findings ◽  
Nuclear Waste Forms ◽  
Leaching Models ◽  
Surface Layer Formation

Leachability is one of the most important properties of solidified nuclear waste forms because it provides information on the performance and the subsequent safety and reliability that the waste products will possess. One of the most important experimental findings in the leachability field has been the discovery and subsequent detailed characterization of protective surface layers that form on waste glass during leaching. These layers can have a beneficial effect on product performance while in storage by improving productdurability with time. As a result of surface layer formation and the effects on subsequent product leaching characteristics, new qualitative and quantitative leaching models have recently been proposed.

Surface Layer Formation on a Nuclear Waste Glass

1982 ◽  
Vol 15 ◽  
Author(s):  
Werner Lutze ◽  
GÜnter Malow ◽  
Harald Rabe ◽  
Thomas J. Headley
Keyword(s):  
Waste Glass ◽  
Layer Formation ◽  
Surface Layers ◽  
Protective Function ◽  
Leach Rate ◽  
Simulated Waste ◽  
Volcanic Glasses ◽  
The Stability ◽  
Kinetics Of ◽  
Surface Layer Formation

Surface layers are a common feature of leached surfaces of borosilicate waste glasses. Layers are also observed upon weathering of volcanic glasses[l] and of silicate minerals[2]. The question of whether these layers can protect the glass against further attack by decreasing the leach rate is stïll a subject of controversy[3]. Both in geochemical work[4] and in work on waste forms [5,6], surface layers are attributed a protective function, and the stability of leached, million years old volcanic glasses[1] may be due to the presence of palagonite, a thin (≤100 μm) alteration layer, which forms in a few years but does not seem to increase in thickness after this time. The present study investigates the effects of layer formation on leaching kinetics of a borosilicate waste glass containing 20 wt.% LWR-type simulated waste oxides.

Mechanical characterization of miniaturized functional substrates and components in different environments

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000085-000091
Author(s):  
Raul Bermejo ◽  
Clemens Krautgasser ◽  
Marco Deluca ◽  
Martin Pletz ◽  
Peter Supancic ◽  
...  
Keyword(s):  
Environmental Degradation ◽  
Protective Layer ◽  
Strength Distribution ◽  
Rectangular Plates ◽  
Biaxial Testing ◽  
Surface Features ◽  
Silicon Chips ◽  
Experimental Findings ◽  
Functional Components

Functional components such as multilayer low temperature co-fired ceramics are examples of the combination of a ceramic-based substrate with internal electrodes as well as surface features (e.g. metallization, contacting pads, cylindrical vias, etc) employed to provide the component with a given functionality. Another example is that of functionalized silicon chips to be embedded into polymer circuit boards in order to enhance integration and save costs. The functionality of the system can be influenced by the mechanical reliability of the different components. Due to miniaturization and design complexity, no standard methods for mechanical testing can be applied for the characterization of these brittle components. In this work, an experimental approach is presented, which enables determining the strength distribution in functional components (e.g. rectangular plates as small as 2 × 2 × 0.1 mm3) in different environments at different temperatures. The method is based on localized biaxial testing using a ball-on-three-balls fixture. The high accuracy of the test allows quantifying the effect of surface quality, surface features and/or metallization (e.g. contact pads or cylindrical vias) on the component strength distribution. Experimental findings show that the strength distribution of ceramic components can be affected by environmental degradation, whereby subcritical crack growth phenomena can be enhanced in environments with high relative humidity. In addition, metallization at the surface subjected to tensile stresses can even raise the strength of the component, acting as a protective layer against environmental degradation, whereas cylindrical vias can become weak points in the design. It is shown that functionalized layers such as those used in silicon chips can have a significant effect on the strength parameters, thus influencing the lifetime of the device.

scholarly journals Characterization of swelling behavior of carbon nano-filler modified polydimethylsiloxane composites

2021 ◽  
pp. 009524432110061
Author(s):  
Bo Yang ◽  
Balakrishnan Nagarajan ◽  
Pierre Mertiny
Keyword(s):  
Digital Image Analysis ◽  
Swelling Behavior ◽  
Optical Measurements ◽  
Natural Phenomenon ◽  
Cross Linking ◽  
Dimensional Changes ◽  
Experimental Findings ◽  
Carbon Based

Polymers may absorb fluids from their surroundings via the natural phenomenon of swelling. Dimensional changes due to swelling can affect the function of polymer components, such as in the case of seals, microfluidic components and electromechanical sensors. An understanding of the swelling behavior of polymers and means for controlling it can improve the design of polymer components, for example, for the previously mentioned applications. Carbon-based fillers have risen in popularity to be used for the property enhancement of resulting polymer composites. The present investigation focuses on the effects of three carbon-based nano-fillers (graphene nano-platelets, carbon black, and graphene nano-scrolls) on the dimensional changes of polydimethylsiloxane composites due to swelling when immersed in certain organic solvents. For this study, a facile and expedient methodology comprised of optical measurements in conjunction with digital image analysis was developed as the primary experimental technique to quantify swelling dimensional changes of the prepared composites. Other experimental techniques assessed polymer cross-linking densities and elastic mechanical properties of the various materials. The study revealed that the addition of certain carbon-based nano-fillers increased the overall swelling of the composites. The extent of swelling further depended on the organic solvent in which the composites were immersed in. Experimental findings are contrasted with published models for swelling prediction, and the role of filler morphology on swelling behavior is discussed.

Investigation of in-vitro bacterial surface layer formation by FBARs

2009 ◽  
Author(s):  
Michael Mertig ◽  
Anja Bluher ◽  
Christiane Erler ◽  
Beate Katzschner ◽  
Wolfgang Pompe ◽  
...  
Keyword(s):  
Surface Layer ◽  
Layer Formation ◽  
Bacterial Surface ◽  
Surface Layer Formation

Physicochemical and Biological Treatability Studies on Surfactant Wastewaters

1992 ◽  
Vol 26 (1-2) ◽  
pp. 377-386 ◽  
Author(s):  
F. Çeçen
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Heavy Duty ◽  
Surface Active Agents ◽  
Surface Active ◽  
Liquid Type ◽  
Experimental Findings ◽  
Biological Treatability ◽  
Anionic Surface

Laboratory-scale physicochemical and biological treatability studies were performed on wastewaters discharged from an industry producing household and heavy-duty detergents of powder and liquid type. The characterization of effluents led to the conclusion that the industry was highly pollutant in terms of BOD5, COD, surfactant, phosphorus, oil-grease, suspended solids and pH. By the use of lime in the precipitation stage about 80 % of COD and more than 90 % of phosphorus and anionic surface active agents could be removed. Following the treatment with lime the biodegradation of these wastewaters was investigated in continuously fed activated sludge units. The biokinetic constants of the reaction were determined as k = 0.76 d−1, Ks = 972 mg/l COD, a = 0.58 mg O2/mg COD, b = 0.044 mg O2/mg MLVSS.d. The experimental findings were used in the design of a full-scale treatment system.

scholarly journals MODIFICATION AND CHARACTERIZATION OF CEIBA PENTANDRA (L.) GAERTN. (KAPOK) FIBER: PHYSICAL PROPERTIES

2019 ◽  
Vol 7 (7) ◽  
pp. 381-390
Author(s):  
Eduart Wolok ◽  
Idham Halid Lahay ◽  
Buyung R. Machmoed ◽  
Fahriadi Pakaya
Keyword(s):  
Heavy Metals ◽  
Physical Properties ◽  
Protective Layer ◽  
Absorption Capacity ◽  
Natural Material ◽  
Cellulose Content ◽  
Kapok Fiber ◽  
Fiber Properties ◽  
Kapok Fibers

Kapok fiber is a natural material that has unique properties, can be renewed with a large lumen, it has hydrophobic properties, as an absorbent in oil, heavy metals, and sound. To increase the absorption capacity of heavy metals, physical properties, and chemical resistance, modifications were made to change the fiber properties from hydrophobic to hydrophilic. One way is through the process of soaking the kapok fibers in a solvent to remove non-cellulose compounds. In this study, to improve the properties of kapok fiber, soaking has been done with various solutions, there are HCl, NaOH, NaClO, NaClO-NaOH-NaClO, and NaClO2-NaOH-NaClO2 solution. Immersion of kapok fibers in NaClO2-NaOH-NaClO2 solution can increase cellulose content up to 93.69% with porosity content of 4.75%. NaClO2-NaOH-NaClO2-treated can absorb water up to 211.27%, the second highest after treatment with the NaClO-NaOH-NaClO-treated solution of 285.29%. Immersion in NaClO-NaOH-NaClO and NaClO2-NaOH-NaClO2 solvents also causes damage to the kapok fiber protective layer which indicates the loss of lignin, so that a significant change of the hydrophobic fiber becomes hydrophilic as seen in the SEM results.

Sign in / Sign up

Export Citation Format

Share Document