A new theory aiming to define the mechanisms of material removal in electroerosion

NASA Technical Reports Server (NTRS)

Chincholle, L.

1985-01-01

Formulation of an electrohydrodynamic hypothesis to explain the mechanism of material removal in electroerosion, and results of experiments designed to verify the validity of the proposed hypothesis is discussed. A hypothesis is proposed according to which material is removed by a high-power liquid microjet which forms as a result of implosion of a vapor cavity between the two electrodes. Using a model of the implosion of a vapor cavity, a study is made of the energy dissipated in the arc zone as a function of the expended electrical energy.

A new theory aiming to define the mechanisms of material removal in electroerosion

NASA Astrophysics Data System (ADS)

Chincholle, L.

1985-06-01

Formulation of an electrohydrodynamic hypothesis to explain the mechanism of material removal in electroerosion, and results of experiments designed to verify the validity of the proposed hypothesis is discussed. A hypothesis is proposed according to which material is removed by a high-power liquid microjet which forms as a result of implosion of a vapor cavity between the two electrodes. Using a model of the implosion of a vapor cavity, a study is made of the energy dissipated in the arc zone as a function of the expended electrical energy.

Preparation of thiol-functionalized activated carbon from sewage sludge with coal blending for heavy metal removal from contaminated water.

PubMed

Li, Juan; Xing, Xing; Li, Jiao; Shi, Mei; Lin, Aijun; Xu, Congbin; Zheng, Jianzhong; Li, Ronghua

2018-03-01

Sewage sludge produced from wastewater treatment is a pressing environmental issue. Mismanagement of the massive amount of sewage sludge would threat our valuble surface and shallow ground water resources. Use of activated carbon prepared from carbonization of these sludges for heavy metal removal can not only minimize and stabilize these hazardous materials but also realize resources reuse. In this study, thiol-functionalized activated carbon was synthesized from coal-blended sewage sludge, and its capacity was examined for removing Cu(II), Pb(II), Cd(II) and Ni(II) from water. Pyrolysis conditions to prepare activated carbons from the sludge and coal mixture were examined, and the synthesized material was found to achieve the highest BET surface area of 1094 m 2 /g under 500 °C and 30 min. Batch equilibrium tests indicated that the thiol-functionalized activated carbon had a maximum sorption capacity of 238.1, 96.2, 87.7 and 52.4 mg/g for Pb(II), Cd(II), Cu(II) and Ni(II) removal from water, respectively. Findings of this study suggest that thiol-functionalized activated carbon prepared from coal-blended sewage sludge would be a promising sorbent material for heavy metal removal from waters contaminated with Cu(II), Pb(II), Cd(II) and Ni(II). Copyright © 2017 Elsevier Ltd. All rights reserved.

Normal force and drag force in magnetorheological finishing

NASA Astrophysics Data System (ADS)

Miao, Chunlin; Shafrir, Shai N.; Lambropoulos, John C.; Jacobs, Stephen D.

2009-08-01

The material removal in magnetorheological finishing (MRF) is known to be controlled by shear stress, λ, which equals drag force, Fd, divided by spot area, As. However, it is unclear how the normal force, Fn, affects the material removal in MRF and how the measured ratio of drag force to normal force Fd/Fn, equivalent to coefficient of friction, is related to material removal. This work studies, for the first time for MRF, the normal force and the measured ratio Fd/Fn as a function of material mechanical properties. Experimental data were obtained by taking spots on a variety of materials including optical glasses and hard ceramics with a spot-taking machine (STM). Drag force and normal force were measured with a dual load cell. Drag force decreases linearly with increasing material hardness. In contrast, normal force increases with hardness for glasses, saturating at high hardness values for ceramics. Volumetric removal rate decreases with normal force across all materials. The measured ratio Fd/Fn shows a strong negative linear correlation with material hardness. Hard materials exhibit a low "coefficient of friction". The volumetric removal rate increases with the measured ratio Fd/Fn which is also correlated with shear stress, indicating that the measured ratio Fd/Fn is a useful measure of material removal in MRF.

Normal Force and Drag Force in Magnetorheological Finishing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao, C.; Shafrir, S.N.; Lambropoulos, J.C.

2010-01-13

The material removal in magnetorheological finishing (MRF) is known to be controlled by shear stress, tau, which equals drag force, Fd, divided by spot area, As. However, it is unclear how the normal force, Fn, affects the material removal in MRF and how the measured ratio of drag force to normal force Fd/Fn, equivalent to coefficient of friction, is related to material removal. This work studies, for the first time for MRF, the normal force and the measured ratio Fd/Fn as a function of material mechanical properties. Experimental data were obtained by taking spots on a variety of materials includingmore » optical glasses and hard ceramics with a spot-taking machine (STM). Drag force and normal force were measured with a dual load cell. Drag force decreases linearly with increasing material hardness. In contrast, normal force increases with hardness for glasses, saturating at high hardness values for ceramics. Volumetric removal rate decreases with normal force across all materials. The measured ratio Fd/Fn shows a strong negative linear correlation with material hardness. Hard materials exhibit a low “coefficient of friction”. The volumetric removal rate increases with the measured ratio Fd/Fn which is also correlated with shear stress, indicating that the measured ratio Fd/Fn is a useful measure of material removal in MRF.« less

Systems and strippable coatings for decontaminating structures that include porous material

DOEpatents

Fox, Robert V [Idaho Falls, ID; Avci, Recep [Bozeman, MT; Groenewold, Gary S [Idaho Falls, ID

2011-12-06

Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

Method of making thermally removable polyurethanes

DOEpatents

Loy, Douglas A.; Wheeler, David R.; McElhanon, James R.; Saunders, Randall S.; Durbin-Voss, Marvie Lou

2002-01-01

A method of making a thermally-removable polyurethane material by heating a mixture of a maleimide compound and a furan compound, and introducing alcohol and isocyanate functional groups, where the alcohol group and the isocyanate group reacts to form the urethane linkages and the furan compound and the maleimide compound react to form the thermally weak Diels-Alder adducts that are incorporated into the backbone of the urethane linkages during the formation of the polyurethane material at temperatures from above room temperature to less than approximately 90.degree. C. The polyurethane material can be easily removed within approximately an hour by heating to temperatures greater than approximately 90.degree. C. in a polar solvent. The polyurethane material can be used in protecting electronic components that may require subsequent removal of the solid material for component repair, modification or quality control.

Removal of Pertechnetate-Related Oxyanions from Solution Using Functionalized Hierarchical Porous Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, Debasis; Elsaidi, Sameh K.; Aguila, Briana

2016-10-20

Efficient and cost-effective removal of radioactive pertechnetate anions from nuclear waste is a key challenge to mitigate long-term nuclear waste storage issues. Traditional materials such as resins and layered double hydroxides (LDHs) were evaluated for their pertechnetate or perrhenate (the non-radioactive surrogate) removal capacity, but there is room for improvement in terms of capacity, selectivity and kinetics. A series of functionalized hierarchical porous frameworks were evaluated for their perrhenate removal capacity in the presence of other competing anions.

Rapid fabrication of a silicon modification layer on silicon carbide substrate.

PubMed

Bai, Yang; Li, Longxiang; Xue, Donglin; Zhang, Xuejun

2016-08-01

We develop a kind of magnetorheological (MR) polishing fluid for the fabrication of a silicon modification layer on a silicon carbide substrate based on chemical theory and actual polishing requirements. The effect of abrasive concentration in MR polishing fluid on material removal rate and removal function shape is investigated. We conclude that material removal rate will increase and tends to peak value as the abrasive concentration increases to 0.3 vol. %, and the removal function profile will become steep, which is a disadvantage to surface frequency error removal at the same time. The removal function stability is also studied and the results show that the prepared MR polishing fluid can satisfy actual fabrication requirements. An aspheric reflective mirror of silicon carbide modified by silicon is well polished by combining magnetorheological finishing (MRF) using two types of MR polishing fluid and computer controlled optical surfacing (CCOS) processes. The surface accuracy root mean square (RMS) is improved from 0.087λ(λ=632.8  nm) initially to 0.020λ(λ=632.8  nm) in 5.5 h total and the tool marks resulting from MRF are negligible. The PSD analysis results also shows that the final surface is uniformly polished.

[Upgrading of complete removable prosthetic appliance of stomatological patients by the use of new base materials].

PubMed

Кузь, Виталий С; Дворник, Валентин Н; Тесленко, Александра И; Кузь, Гельфира М; Мартыненко, Игорь Н

2016-01-01

The effectiveness of orthopedic treatment of edentulous patients depends on the properties of the basic materials. The main group of materials for manufacturing of such structures are acrylic plastics of thermal polymerization. However, many years of experience in the use of plastics has revealed a number of shortcomings. One of the main is insufficient functional durability of prostheses, and as a consequence - the fragility of acrylic constructions. At present, more and more dentists use nonacrylic thermoplastics, which can improve the functional quality of full removable dentures, as well as, avoid the above disadvantages of acrylic basic plastic. The work is devoted to the study of comparative clinical effectiveness of dental prosthetic in edentulous patients using a variety of basic materials for the production of removable dentures. In this work we used the following materials - "Ftorax" - acrylic plastic of hot polymerization and «Vertex Thermosense» - nonacrylic thermoplastic plastic. As a result of the performed work it can be concluded that the use of the basic thermoplastic materials, namely «Vertex Thermosense», allows to get more rapid adaptation of the patient to full removable dentures due to better fixation and stabilization. Based on the results of our comparative clinical study it can be recommended using of base material «Vertex Thermosense» in the clinic of prosthetic dentistry in treatment of edentulous patients.

Exploration of material removal rate of srf elliptical cavities as a function of media type and cavity shape on niobium and copper using centrifugal barrel polishing (cbp)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palczewski, Ari; Ciovati, Gianluigi; Li, Yongming

Centrifugal barrel polishing (cbp) for SRF application is becoming more wide spread as the technique for cavity surface preparation. CBP is now being used in some form at SRF laboratories around the world including in the US, Europe and Asia. Before the process can become as mature as wet chemistry like eletro-polishing (EP) and buffered chemical polishing (BCP) there are many questions which remain unanswered. One of these topics includes the uniformity of removal as a function of cavity shape and material type. In this presentation we show CBP removal rates for various media types on 1.3 GHz TESLA andmore » 1.5 GHz CEBAF large/fine grain niobium cavities, and 1.3GHz low surface field copper cavity. The data will also include calculated RF frequency shift modeling non-uniform removal as a function of cavity position and comparing them with CBP results.« less

A comparison of neural network architectures for the prediction of MRR in EDM

NASA Astrophysics Data System (ADS)

Jena, A. R.; Das, Raja

2017-11-01

The aim of the research work is to predict the material removal rate of a work-piece in electrical discharge machining (EDM). Here, an effort has been made to predict the material removal rate through back-propagation neural network (BPN) and radial basis function neural network (RBFN) for a work-piece of AISI D2 steel. The input parameters for the architecture are discharge-current (Ip), pulse-duration (Ton), and duty-cycle (τ) taken for consideration to obtained the output for material removal rate of the work-piece. In the architecture, it has been observed that radial basis function neural network is comparatively faster than back-propagation neural network but logically back-propagation neural network results more real value. Therefore BPN may consider as a better process in this architecture for consistent prediction to save time and money for conducting experiments.

Functional materials based on nanocrystalline cellulose

NASA Astrophysics Data System (ADS)

Surov, O. V.; Voronova, M. I.; Zakharov, A. G.

2017-10-01

The data on the synthesis of functional materials based on nanocrystalline cellulose (NCC) published over the past 10 years are analyzed. The liquid-crystal properties of NCC suspensions, methods of investigation of NCC suspensions and films, conditions for preserving chiral nematic structure in the NCC films after removal of the solvent and features of templated sol-gel synthesis of functional materials based on NCC are considered. The bibliography includes 106 references.

Removal of DLC film on polymeric materials by low temperature atmospheric-pressure plasma jet

NASA Astrophysics Data System (ADS)

Kobayashi, Daichi; Tanaka, Fumiyuki; Kasai, Yoshiyuki; Sahara, Junki; Asai, Tomohiko; Hiratsuka, Masanori; Takatsu, Mikio; Koguchi, Haruhisa

2017-10-01

Diamond-like carbon (DLC) thin film has various excellent functions. For example, high hardness, abrasion resistance, biocompatibility, etc. Because of these functionalities, DLC has been applied in various fields. Removal method of DLC has also been developed for purpose of microfabrication, recycling the substrate and so on. Oxygen plasma etching and shot-blast are most common method to remove DLC. However, the residual carbon, high cost, and damage onto the substrate are problems to be solved for further application. In order to solve these problems, removal method using low temperature atmospheric pressure plasma jet has been developed in this work. The removal effect of this method has been demonstrated for DLC on the SUS304 substrate. The principle of this method is considered that oxygen radical generated by plasma oxidize carbon constituting the DLC film and then the film is removed. In this study, in order to widen application range of this method and to understand the mechanism of film removal, plasma irradiation experiment has been attempted on DLC on the substrate with low heat resistance. The DLC was removed successfully without any significant thermal damage on the surface of polymeric material.

Feasibility study for removing calcified material using a planar rectangular ultrasound transducer.

PubMed

Damianou, Christakis; Couppis, Andreas

2016-01-01

The aim of the proposed study was to conduct a feasibility study using a flat rectangular (3 mm × 10 mm) MRI compatible transducer operating at 5.3 MHz for destroying calcified material in an in vitro model. The proposed method can be used in the future for treating atherosclerosis plaques of the coronary, carotid or peripheral arteries. The system was tested initially on calcium rods. Another test was performed in a hydroxyapatite-polylactide model. A parametric study was performed where the mass of calcified material removed was studied as a function of intensity, pulse repetition frequency (PRF), duty factor (DF) and presence of bubbles. The amount of calcified material removed is directly related to the intensity, PRF and DF. It was found that the presence of bubbles accelerates the removal of calcified material. In order to ensure that pure mechanical mode ultrasound was used, the protocols were designed so that the temperature does not exceed 1 °C.

Detoxification of zearalenone from corn oil by adsorption of functionalized GO systems

NASA Astrophysics Data System (ADS)

Bai, Xiaojuan; Sun, Changpo; Xu, Jing; Liu, Di; Han, Yangying; Wu, Songling; Luo, Xiaohong

2018-02-01

Graphene oxide (GO) and its functionalized systems have very unique structural advantages as excellent adsorbent or substrate material in the removal of organic contaminants. Herein, we reported a strategy to establish functionalized GO system (FGO) using amphiphilic molecules didodecyldimethylammonium bromide (DDAB) as a modifier for the detoxification of zearalenone (ZEN) from corn oil. The adsorption property for the removal of ZEN from edible corn oils under different experimental conditions such as pH, amphiphilic molecules, time and temperature was investigated in detail. The morphology structure, adsorption isotherm, adsorption kinetics and the recyclability of FGO systems have also been researched, systematically. The FGO systems exhibit a higher adsorption efficiency, recyclability and thermostability in comparison with the traditional adsorbent materials. It provides an insight into the detoxification of mycotoxin from edible oils by graphene-based new materials.

New insights into the effects of support matrix on the removal of organic micro-pollutants and the microbial community in constructed wetlands.

PubMed

Zhang, Liang; Lyu, Tao; Ramírez Vargas, Carlos Andrés; Arias, Carlos A; Carvalho, Pedro N; Brix, Hans

2018-09-01

Constructed wetlands (CWs) are an eco-friendly and cost-effective technology to remove organic micro-pollutants (OMPs) from wastewater. The support matrix is an important component in CWs as it has a primary role in the growth and development of plants and microbes. However, the roles of the support matrix in CWs in removing OMPs have not been systematically studied. Therefore, in this study, six common materials (sand, zeolite, blast iron slag, petcoke, polonite and crushed autoclaved aerated concrete (CAAC)) as support matrixes were firstly investigated by batch tests to explore their adsorption capacities to selected OMPs (ibuprofen, iohexol, tebuconazole and imazalil). Results showed that the adsorption capacities of the materials were low (at the level of μg/g) compared to well-known sorbents (at the level of mg/g), such as activated carbon and carbon nanotubes. Columns packed with the six materials, respectively, were then built up to study the effects of different materials on microbial community. In the medium-term study (66 days), the removal of four OMPs in all the columns increased by 2-58% from day 25 to day 66, and was mainly attributed to microbial degradation. Furthermore, Community-level physiological profiling (CLPP) analysis indicates that material presence shaped the microbial community metabolic function not only in the interstitial water but also in the biofilm. Overall, all the findings demonstrate that although the adsorption capacities of the common materials are low, they may be a driver to improve the removal of OMPs by altering microbial community function in CWs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Nanoporous Block Polymer Thin Films Functionalized with Bio-Inspired Ligands for the Efficient Capture of Heavy Metal Ions from Water.

PubMed

Weidman, Jacob L; Mulvenna, Ryan A; Boudouris, Bryan W; Phillip, William A

2017-06-07

Heavy metal contamination of water supplies poses a serious threat to public health, prompting the development of novel and sustainable treatment technologies. One promising approach is to molecularly engineer the chemical affinity of a material for the targeted removal of specific molecules from solution. In this work, nanoporous polymer thin films generated from tailor-made block polymers were functionalized with the bio-inspired moieties glutathione and cysteamine for the removal of heavy metal ions, including lead and cadmium, from aqueous solutions. In a single equilibrium stage, the films achieved removal rates of the ions in excess of 95%, which was consistent with predictions based on the engineered material properties. In a flow-through configuration, the thin films achieved an even greater removal rate of the metal ions. Furthermore, in mixed ion solutions the capacity of the thin films, and corresponding removal rates, did not demonstrate any reduction due to competitive adsorption effects. After such experiments the material was repeatedly regenerated quickly with no observed loss in capacity. Thus, these membranes provide a sustainable platform for the efficient purification of lead- and cadmium-contaminated water sources to safe levels. Moreover, their straightforward chemical modifications suggest that they could be engineered to treat sources containing other recalcitrant environmental contaminants as well.

Self assembled molecular monolayers on high surface area materials as molecular getters

DOEpatents

King, David E.; Herdt, Gregory C.; Czanderna, Alvin W.

1997-01-01

The present invention relates to a gettering material that may be used as a filtration medium to remove pollutants from the environment. The gettering material comprises a high surface area material having a metal surface that chemically bonds n-alkanethiols in an organized manner thereby forming a molecular monolayer over the metal surface. The n-alkanethiols have a free functional group that interacts with the environment thereby binding specific pollutants that may be present. The gettering material may be exposed to streams of air in heating, ventilation, and air conditioning systems or streams of water to remove specific pollutants from either medium.

Self assembled molecular monolayers on high surface area materials as molecular getters

DOEpatents

King, D.E.; Herdt, G.C.; Czanderna, A.W.

1997-01-07

The present invention relates to a gettering material that may be used as a filtration medium to remove pollutants from the environment. The gettering material comprises a high surface area material having a metal surface that chemically bonds n-alkanethiols in an organized manner thereby forming a molecular monolayer over the metal surface. The n-alkanethiols have a free functional group that interacts with the environment thereby binding specific pollutants that may be present. The gettering material may be exposed to streams of air in heating, ventilation, and air conditioning systems or streams of water to remove specific pollutants from either medium. 9 figs.

Shear Stress in Magnetorheological FInishing for Glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao, C.; Shafrir, S.N.; Lambropoulos, J.C.

2009-04-28

We report in situ, simultaneous measurements of both drag and normal forces in magnetorheological finishing (MRF) for what is believed to be the first time, using a spot taking machine (STM) as a test bed to take MRF spots on stationary parts. The measurements are carried out over the entire area where material is being removed, i.e., the projected area of the MRF removal function/spot on the part surface, using a dual force sensor. This approach experimentally addresses the mechanisms governing material removal in MRF for optical glasses in terms of the hydrodynamic pressure and shear stress, applied by themore » hydrodynamic flow of magnetorheological fluid at the gap between the part surface and the STM wheel. This work demonstrates that the volumetric removal rate shows a positive linear dependence on shear stress. Shear stress exhibits a positive linear dependence on a material figure of merit that depends upon Young’s modulus, fracture toughness, and hardness. A modified Preston’s equation is proposed that better estimates MRF material removal rate for optical glasses by incorporating mechanical properties, shear stress, and velocity.« less

Shear stress in magnetorheological finishing for glasses.

PubMed

Miao, Chunlin; Shafrir, Shai N; Lambropoulos, John C; Mici, Joni; Jacobs, Stephen D

2009-05-01

We report in situ, simultaneous measurements of both drag and normal forces in magnetorheological finishing (MRF) for what is believed to be the first time, using a spot taking machine (STM) as a test bed to take MRF spots on stationary parts. The measurements are carried out over the entire area where material is being removed, i.e., the projected area of the MRF removal function/spot on the part surface, using a dual force sensor. This approach experimentally addresses the mechanisms governing material removal in MRF for optical glasses in terms of the hydrodynamic pressure and shear stress, applied by the hydrodynamic flow of magnetorheological fluid at the gap between the part surface and the STM wheel. This work demonstrates that the volumetric removal rate shows a positive linear dependence on shear stress. Shear stress exhibits a positive linear dependence on a material figure of merit that depends upon Young's modulus, fracture toughness, and hardness. A modified Preston's equation is proposed that better estimates MRF material removal rate for optical glasses by incorporating mechanical properties, shear stress, and velocity.

Contributions of nanodiamond abrasives and deionized water in magnetorheological finishing of aluminum oxynitriden

NASA Astrophysics Data System (ADS)

Miao, Chunlin; Lambropoulos, John C.; Romanofsky, Henry; Shafrir, Shai N.; Jacobs, Stephen D.

2009-08-01

Magnetorheological finishing (MRF) is a sub-aperture deterministic process for fabricating high-precision optics by removing material and smoothing the surface. The goal of this work is to study the relative contribution of nanodiamonds and water in material removal for MRF of aluminum oxynitride ceramic (ALON) based upon a nonaqueous magnetorheological (MR) fluid. Removal was enhanced by a high carbonyl iron concentration and the addition of nanodiamond abrasives. Small amounts of deionized (DI) water were introduced into the nonaqueous MR fluid to further influence the material removal process. Material removal data were collected with a spot-taking machine. Drag force (Fd) and normal force (Fn) before and after adding nanodiamonds or DI water were measured with a dual load cell. Both drag force and normal force were insensitive to the addition of nanodiamonds but increased with DI water content in the nonaqueous MR fluid. Shear stress (i.e., drag force divided by spot area) was calculated, and examined as a function of nanodiamond concentration and DI water concentration. Volumetric removal rate increased with increasing shear stress, which was shown to be a result of increasing viscosity after adding nanodiamonds and DI water. This work demonstrates that removal rate for a hard ceramic with MRF can be enhanced by adding DI water into a nonaqueous MR fluid.

Sulfur‐Limonene Polysulfide: A Material Synthesized Entirely from Industrial By‐Products and Its Use in Removing Toxic Metals from Water and Soil

PubMed Central

Crockett, Michael P.; Evans, Austin M.; Worthington, Max J. H.; Albuquerque, Inês S.; Slattery, Ashley D.; Gibson, Christopher T.; Campbell, Jonathan A.; Lewis, David A.; Bernardes, Gonçalo J. L.

2015-01-01

Abstract A polysulfide material was synthesized by the direct reaction of sulfur and d‐limonene, by‐products of the petroleum and citrus industries, respectively. The resulting material was processed into functional coatings or molded into solid devices for the removal of palladium and mercury salts from water and soil. The binding of mercury(II) to the sulfur‐limonene polysulfide resulted in a color change. These properties motivate application in next‐generation environmental remediation and mercury sensing. PMID:26481099

Efficiency Evaluation of Food Waste Materials for the Removal of Metals and Metalloids from Complex Multi-Element Solutions

PubMed Central

Giuliano, Antonella; Astolfi, Maria Luisa; Congedo, Rossana; Masotti, Andrea; Canepari, Silvia

2018-01-01

Recent studies have shown the potential of food waste materials as low cost adsorbents for the removal of heavy metals and toxic elements from wastewater. However, the adsorption experiments have been performed in heterogeneous conditions, consequently it is difficult to compare the efficiency of the individual adsorbents. In this study, the adsorption capacities of 12 food waste materials were evaluated by comparing the adsorbents’ efficiency for the removal of 23 elements from complex multi-element solutions, maintaining homogeneous experimental conditions. The examined materials resulted to be extremely efficient for the adsorption of many elements from synthetic multi-element solutions as well as from a heavy metal wastewater. The 12 adsorbent surfaces were analyzed by Fourier transform infrared spectroscopy and showed different types and amounts of functional groups, which demonstrated to act as adsorption active sites for various elements. By multivariate statistical computations of the obtained data, the 12 food waste materials were grouped in five clusters characterized by different elements’ removal efficiency which resulted to be in correlation with the specific adsorbents’ chemical structures. Banana peel, watermelon peel and grape waste resulted the least selective and the most efficient food waste materials for the removal of most of the elements. PMID:29495363

Efficiency Evaluation of Food Waste Materials for the Removal of Metals and Metalloids from Complex Multi-Element Solutions.

PubMed

Massimi, Lorenzo; Giuliano, Antonella; Astolfi, Maria Luisa; Congedo, Rossana; Masotti, Andrea; Canepari, Silvia

2018-02-26

Recent studies have shown the potential of food waste materials as low cost adsorbents for the removal of heavy metals and toxic elements from wastewater. However, the adsorption experiments have been performed in heterogeneous conditions, consequently it is difficult to compare the efficiency of the individual adsorbents. In this study, the adsorption capacities of 12 food waste materials were evaluated by comparing the adsorbents' efficiency for the removal of 23 elements from complex multi-element solutions, maintaining homogeneous experimental conditions. The examined materials resulted to be extremely efficient for the adsorption of many elements from synthetic multi-element solutions as well as from a heavy metal wastewater. The 12 adsorbent surfaces were analyzed by Fourier transform infrared spectroscopy and showed different types and amounts of functional groups, which demonstrated to act as adsorption active sites for various elements. By multivariate statistical computations of the obtained data, the 12 food waste materials were grouped in five clusters characterized by different elements' removal efficiency which resulted to be in correlation with the specific adsorbents' chemical structures. Banana peel, watermelon peel and grape waste resulted the least selective and the most efficient food waste materials for the removal of most of the elements.

Method of making carbon nanotube composite materials

DOEpatents

O'Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

2014-05-20

The present invention is a method of making a composite polymeric material by dissolving a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes and optionally additives in a solvent to make a solution and removing at least a portion of the solvent after casting onto a substrate to make thin films. The material has enhanced conductivity properties due to the blending of the un-functionalized and hydroxylated carbon nanotubes.

Surface functionalized mesoporous material and method of making same

DOEpatents

Feng, Xiangdong [West Richland, WA; Liu, Jun [West Richland, WA; Fryxell, Glen E [Kennewick, WA

2001-12-04

According to the present invention, an organized assembly of functional molecules with specific interfacial functionality (functional group(s)) is attached to available surfaces including within mesopores of a mesoporous material. The method of the present invention avoids the standard base soak that would digest the walls between the mesopores by boiling the mesoporous material in water for surface preparation then removing all but one or two layers of water molecules on the internal surface of a pore. Suitable functional molecule precursor is then applied to permeate the hydrated pores and the precursor then undergoes condensation to form the functional molecules on the interior surface(s) of the pore(s).

Biomolecules for Removal of Heavy Metal.

PubMed

Singh, Namita Ashish

2017-01-01

Patents reveal that heavy metals are natural constituents of the earth's crust, but some heavy metals like cadmium, lead, mercury, arsenic etc. are injurious to living organisms at higher concentration. Nowadays, anthropogenic activities have altered geochemical cycles and biochemical balance of heavy metals. Biomolecules are used nowadays for removal of heavy metals compared to other synthetic biosorbents due to their environmental friendly nature and cost effectiveness. The goal of this work is to identify the role of biomolecules like polysaccharides, polypeptides, natural compounds containing aromatic acid etc. for heavy metal removal by bio sorption. It has been observed that efficiency of biomolecules can be increased by functionalization e.g. cellulose functionalization with EDTA, chitosan with sulphur groups, alginate with carboxyl/ hydroxyl group etc. It was found that the porous structure of aerogel beads improves both sorption and kinetic properties of the material. Out of polypeptides metallothionein has been widely used for removal of heavy metal up to 88% from seawater after a single centrifugation. These cost effective functionalized biomolecules are significantly used for remediation of heavy metals by immobilizing these biomolecules onto materials. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Amino-functionalized MCM-41 and MCM-48 for the removal of chromate and arsenate.

PubMed

Benhamou, A; Basly, J P; Baudu, M; Derriche, Z; Hamacha, R

2013-08-15

The aim of the present work was to investigate the efficiency of three amino-functionalized (hexadecylamine, dodecylamine, and dimethyldodecylamine) mesoporous silicas (MCM-41 and MCM-48) toward the adsorption of arsenate and chromate. Hexadecylamine-functionalized materials were characterized; BET surface areas, pore volumes, and sizes decreased with the functionalization, whereas XRD patterns show that the hexagonal structure of MCM-41 and the cubic structure of MCM-48 were not modified. The zeta potential decreases with pH and the highest arsenate and chromate removal was observed at the lowest pHs. Adsorption of chromium and arsenate was significantly enhanced after functionalization and amino-functionalized MCM-41 adsorb larger amounts of arsenate when compared to expanded MCM-48 materials. Chromate sorption capacities increased with the chain length and the larger capacities were obtained with hexadecylamine-functionalized mesoporous silicas. Mesoporous silicas modified by dimethyldodecylamine exhibited the higher arsenate sorption capacities. Copyright © 2013 Elsevier Inc. All rights reserved.

Material removal and surface figure during pad polishing of fused silica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suratwala, T I; Feit, M D; Steele, W A

2009-05-04

The material removal and surface figure after ceria pad polishing of fused silica glass have been measured and analyzed as a function of kinematics, loading conditions, and polishing time. Also, the friction at the workpiece/lap interface, the slope of the workpiece relative to the lap plane, and lap viscoelastic properties have been measured and correlated to material removal. The results show that the relative velocity between the workpiece & lap (determined by the kinematics) and the pressure distribution determine the spatial and temporal material removal and hence the final surface figure of the workpiece. In the case where the appliedmore » loading and relative velocity distribution over the workpiece are spatially uniform, a significant non-uniform spatial material removal from the workpiece surface is observed. This is due to a non-uniform pressure distribution resulting from: (1) a moment caused by a pivot point and interface friction forces; (2) viscoelastic relaxation of the polyurethane lap; and (3) a physical workpiece/lap interface mismatch. Both the kinematics and these contributions to the pressure distribution are quantitatively described, and then combined to form a spatial and temporal Preston model & code for material removal (called Surface Figure or SurF{copyright}). The surface figure simulations are consistent with the experiment for a wide variety of polishing conditions. This study is an important step towards deterministic full-aperture polishing, which would allow optical glass fabrication to be performed in a more repeatable, less iterative, and hence more economical manner.« less

Method of making nanopatterns and nanostructures and nanopatterned functional oxide materials

DOEpatents

Dravid, Vinayak P; Donthu, Suresh K; Pan, Zixiao

2014-02-11

Method for nanopatterning of inorganic materials, such as ceramic (e.g. metal oxide) materials, and organic materials, such as polymer materials, on a variety of substrates to form nanopatterns and/or nanostructures with control of dimensions and location, all without the need for etching the materials and without the need for re-alignment between multiple patterning steps in forming nanostructures, such as heterostructures comprising multiple materials. The method involves patterning a resist-coated substrate using electron beam lithography, removing a portion of the resist to provide a patterned resist-coated substrate, and spin coating the patterned resist-coated substrate with a liquid precursor, such as a sol precursor, of the inorganic or organic material. The remaining resist is removed and the spin coated substrate is heated at an elevated temperature to crystallize the deposited precursor material.

Contributions of Nanodiamond Abrasives and Deionized Water in Magnetorheological Finishing of Aluminum Oxynitride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao, C.; Lambropoulos, J.C.; Romanofsky, H.

2010-01-13

Magnetorheological finishing (MRF) is a sub-aperture deterministic process for fabricating high-precision optics by removing material and smoothing the surface. The goal of this work is to study the relative contribution of nanodiamonds and water in material removal for MRF of aluminum oxynitride ceramic (ALON) based upon a nonaqueous magnetorheological (MR) fluid. Removal was enhanced by a high carbonyl iron concentration and the addition of nanodiamond abrasives. Small amounts of deionized (DI) water were introduced into the nonaqueous MR fluid to further influence the material removal process. Material removal data were collected with a spot-taking machine. Drag force (Fd) and normalmore » force (Fn) before and after adding nanodiamonds or DI water were measured with a dual load cell. Both drag force and normal force were insensitive to the addition of nanodiamonds but increased with DI water content in the nonaqueous MR fluid. Shear stress (i.e., drag force divided by spot area) was calculated, and examined as a function of nanodiamond concentration and DI water concentration. Volumetric removal rate increased with increasing shear stress, which was shown to be a result of increasing viscosity after adding nanodiamonds and DI water. This work demonstrates that removal rate for a hard ceramic with MRF can be enhanced by adding DI water into a nonaqueous MR fluid.« less

Modified subaperture tool influence functions of a flat-pitch polisher with reverse-calculated material removal rate.

PubMed

Dong, Zhichao; Cheng, Haobo; Tam, Hon-Yuen

2014-04-10

Numerical simulation of subaperture tool influence functions (TIF) is widely known as a critical procedure in computer-controlled optical surfacing. However, it may lack practicability in engineering because the emulation TIF (e-TIF) has some discrepancy with the practical TIF (p-TIF), and the removal rate could not be predicted by simulations. Prior to the polishing of a formal workpiece, opticians have to conduct TIF spot experiments on another sample to confirm the p-TIF with a quantitative removal rate, which is difficult and time-consuming for sequential polishing runs with different tools. This work is dedicated to applying these e-TIFs into practical engineering by making improvements from two aspects: (1) modifies the pressure distribution model of a flat-pitch polisher by finite element analysis and least square fitting methods to make the removal shape of e-TIFs closer to p-TIFs (less than 5% relative deviation validated by experiments); (2) predicts the removal rate of e-TIFs by reverse calculating the material removal volume of a pre-polishing run to the formal workpiece (relative deviations of peak and volume removal rate were validated to be less than 5%). This can omit TIF spot experiments for the particular flat-pitch tool employed and promote the direct usage of e-TIFs in the optimization of a dwell time map, which can largely save on cost and increase fabrication efficiency.

Mesoporous (organo) silica decorated with magnetic nanoparticles as a reusable nanoadsorbent for arsenic removal from water samples.

PubMed

Hasanzadeh, Mohammad; Farajbakhsh, Farzad; Shadjou, Nasrin; Jouyban, Abolghasem

2015-01-01

Over the last decade, numerous removal methods using solid-supported magnetic nanocomposites have been employed in order to remove arsenic from aqueous solution. In this report, removal of arsenic from aqueous solution by an organo silica, namely, magnetic mobile crystalline material-41 (MCM-41) functionalized by chlorosulphonic acid (MMCM-41-SO3H), was investigated using atomic absorption spectroscopy. The synthesized magnetic mesoporous materials have satisfactory As (V) adsorption capacity. Linearity for arsenic was observed in the concentration range of 5-100 ppb. In addition, the coefficient of determination (R2) was more than 0.999 and the limit of detection (LOD) was 0.061 ppb. Considering these results, MMCM-41-SO3H has a great potential for the removal of As (V) contaminants and potentially for the application in large-scale wastewater treatment plants.

Surface modification of polymeric foams for oil spills remediation.

PubMed

Pinto, Javier; Athanassiou, Athanassia; Fragouli, Despina

2018-01-15

In the last decade, a continuous increasing research activity is focused on the surface functionalization of polymeric porous materials for the efficient removal of oil contaminants from water. This work reviews the most significant recent studies on the functionalization of polyurethane and melamine foams, materials commonly reported for oil-water separation applications. After the identification of the key features of the foams required to optimize their oil removal performance, a wide variety of physicochemical treatments are described together with their effect on the oil absorption selectivity and oil absorption capacity, both critical parameters for the application of the foams in the remediation of oil spills. The efficiencies of the different functionalization processes on the same type of foams are compared, determining the main advantages and potentialities of each treatment and remediation procedure. Copyright © 2017 Elsevier Ltd. All rights reserved.

2-Hydroxy-naphthyl functionalized mesoporous silica for fluorescence sensing and removal of aluminum ions.

PubMed

Das, Trisha; Roy, Ankita; Uyama, Hiroshi; Roy, Partha; Nandi, Mahasweta

2017-06-06

Mesoporous silica functionalized with a 2-hydroxy-naphthyl moiety has been synthesized and characterized by standard techniques like powder X-ray diffraction, N 2 adsorption/desorption studies, transmission electron microscopy and spectral studies like FT-IR, UV-visible, fluorescence and 13 C and 29 Si solid state NMR. The functionalized silica material showed significant enhancement in its emission intensity in the presence of Al 3+ ions whereas other metal ions could not bring about any increase in its emission intensity. They either quench the emission or do not alter the intensity significantly making the functionalized material a fluorescence chemosensor for Al 3+ . The sensitivity of the probe towards Al 3+ has been determined to be high with a low limit of detection value. As functionalized silica is not soluble in common solvents, it has been effectively used to bind and remove Al 3+ from a solution. Theoretical calculations on a model system have been performed to investigate the electronic spectral transitions.

Synthesis, Characterization, and Environmental Applications of Hybrid Materials Based on Humic Acid Obtained by the Sol-Gel Route.

PubMed

Oliveira, Lílian Karla de; Molina, Eduardo Ferreira; Moura, André L A; de Faria, Emerson Henrique; Ciuffi, Katia Jorge

2016-01-20

Humic acids (HAs) are ubiquitous macromolecules in the environment. Due to their high contents of oxygenated functional groups, they can interact with contaminants present in the natural environment and therefore influence the behavior of pollutants. However, a pH of 2 or lower is required to maintain HAs in the solid form. To increase the stability of HAs and their capacity to bind to contaminants, this work proposes the development of new hybrid materials based on alkoxysilanes and HAs for environmental applications such as dye adsorption. Three different materials with new functional groups were prepared by employing the following alkoxysilanes: tetraethyl orthosilicate, (3-aminopropyl)triethoxysilane, and N-[3-(trimethoxylsilyl)propyl]ethylenediamine. The final materials were denoted HWA, HOA, and HTA, respectively, and they were characterized by elemental analysis, diffuse reflectance Fourier-transform infrared spectroscopy (DRIFT), small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), and N2 gas-volumetric adsorption. The point of zero charge (pzc) and stability of these materials were also determined. Their selectivity was evaluated in adsorption experiments performed with two different charged dyes in aqueous medium, namely anionic rose bengal (RB) and cationic methylene blue (MB). The elemental, DRIFT, SAXS, SEM, and textural analyses confirmed the presence of a combination of the features of HAs and alkoxysilanes. The pzc results showed that the new materials displayed different characteristics and affinities. All the materials were stable in aqueous solution up to pH 10. For MB, the percentage removal values obtained by using HWA, HOA, and HTA were 98, 85, and 67%, respectively. As for RB, the percentage removal values were 19, 18, and 44% for HWA, HOA, and HTA, respectively. These hybrid materials have potential use as adsorbents for the removal of cationic or anionic species and could be viable alternatives to remove various substances present as contaminants in natural environments.

Removal of metals from aqueous solution and sea water by functionalized graphite nanoplatelets based electrodes.

PubMed

Mishra, Ashish Kumar; Ramaprabhu, S

2011-01-15

In the present wok, we have demonstrated the simultaneous removal of sodium and arsenic (pentavalent and trivalent) from aqueous solution using functionalized graphite nanoplatelets (f-GNP) based electrodes. In addition, these electrodes based water filter was used for multiple metals removal from sea water. Graphite nanoplatelets (GNP) were prepared by acid intercalation and thermal exfoliation. Functionalization of GNP was done by further acid treatment. Material was characterized by different characterization techniques. Performance of supercapacitor based water filter was analyzed for the removal of high concentration of arsenic (trivalent and pentavalent) and sodium as well as for desalination of sea water, using cyclic voltametry (CV) and inductive coupled plasma-optical emission spectroscopy (ICP-OES) techniques. Adsorption isotherms and kinetic characteristics were studied for the simultaneous removal of sodium and arsenic (both trivalent and pentavalent). Maximum adsorption capacities of 27, 29 and 32 mg/g for arsenate, arsenite and sodium were achieved in addition to good removal efficiency for sodium, magnesium, calcium and potassium from sea water. Copyright © 2010 Elsevier B.V. All rights reserved.

THE USE OF ARCHITECTURAL ACOUSTICAL MATERIALS, THEORY AND PRACTICE. SECOND EDITION.

ERIC Educational Resources Information Center

Acoustical Materials Association, New York, NY.

THIS DISCUSSION OF THE BASIC FUNCTION OF ACOUSTICAL MATERIALS--THE CONTROL OF SOUND BY SOUND ABSORPTION--IS BASED ON THE WAVE AND ENERGY PROPERTIES OF SOUND. IT IS STATED THAT, IN GENERAL, A MUCH LARGER VOLUME OF ACOUSTICAL MATERIALS IS NEEDED TO REMOVE DISTRACTING NOISE FROM CLASSROOMS AND OFFICES, FOR EXAMPLE, THAN FROM AUDITORIUMS, WHERE A…

Flight Performance of an Advanced Thermal Protection Material: Toughened Uni-Piece Fibrous Insulation

NASA Technical Reports Server (NTRS)

Leiser, Daniel B.; Gordon, Michael P.; Rasky, Daniel J. (Technical Monitor)

1995-01-01

The flight performance of a new class of low density, high temperature thermal protection materials (TPM) is described and compared to "standard" Space Shuttle TPM. This new functionally gradient material designated as Toughened Uni-Piece Fibrous Insulation (TUFI), was bonded on a removable panel attached to the base heat shield of Orbiter 105, Endeavour.

Flight Performance of an Advanced Thermal Protection Material: Toughened Uni-Piece Fibrous Insulation

NASA Technical Reports Server (NTRS)

Leiser, Daniel B.; Gordon, Michael P.; Rasky, Daniel J. (Technical Monitor)

1995-01-01

The flight performance of a new class of low density, high temperature, thermal protection materials (TPM), is described and compared to "standard" Space Shuttle TPM. This new functionally gradient material designated as Toughened Uni-Piece Fibrous Insulation (TUFI), was bonded on a removable panel attached to the base heatshield of Orbiter 105, Endeavor.

An Innovative Porous Nanocomposite Material for the Removal of Phenolic Compounds from Aqueous Solutions.

PubMed

Turco, Antonio; Monteduro, Anna Grazia; Mazzotta, Elisabetta; Maruccio, Giuseppe; Malitesta, Cosimino

2018-05-16

Energy efficient, low-cost, user-friendly, and green methods for the removal of toxic phenolic compounds from aqueous solution are necessary for waste treatment in industrial applications. Herein we present an interesting approach for the utilization of oxidized carbon nanotubes (CNTs) in the removal of phenolic compounds from aqueous solution. Dried pristine CNTs were stably incorporated in a solid porous support of polydimethylsiloxane (PDMS) facilitating the handling during both oxidation process of the nanomaterial and uptake of phenolic compounds, and enabling their safe disposal, avoiding expensive post-treatment processes. The adsorption studies indicated that the materials can efficiently remove phenolic compounds from water with different affinities towards different phenolic compounds. Furthermore, the adsorption kinetics and isotherms were studied in detail. The experimental data of adsorption fitted well with Langmuir and Freundlich isotherms, and pseudo-second-order kinetics, and the results indicated that the adsorption process was controlled by a two-step intraparticle diffusion model. The incorporation of CNTs in polymeric matrices did not affect their functionality in phenol uptake. The material was also successfully used for the removal of phenolic compounds from agricultural waste, suggesting its possible application in the treatment of wastewater. Moreover, the surface of the material could be regenerated, decreasing treatment costs.

Improvement of cadmium ion removal by base treatment of juniper fiber

Treesearch

S.H. Min; J.S. Han; E.W. Shin; J.K. Park

2004-01-01

Juniper is a small-diameter underutilized lignocellulosic material. We evaluated the efficacy of base-treated juniper fiber (BTJF) for cadmium (Cd2+) sorption and the viability of juniper fiber as a sorbent for removing Cd2+ from water. Fourier transform infrared spectroscopy analysis indicated that carboxylate ion is a major functional group responsible for Cd2+...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wojciechowski, Kenneth; Olsson, Roy; Clews, Peggy J.

Thermally isolated devices may be formed by performing a series of etches on a silicon-based substrate. As a result of the series of etches, silicon material may be removed from underneath a region of an integrated circuit (IC). The removal of the silicon material from underneath the IC forms a gap between remaining substrate and the integrated circuit, though the integrated circuit remains connected to the substrate via a support bar arrangement that suspends the integrated circuit over the substrate. The creation of this gap functions to release the device from the substrate and create a thermally-isolated integrated circuit.

Evaluation of silica/ferrocyanide composite as a dual-function material for simultaneous removal of ¹³⁷Cs⁺ and ⁹⁹TcO₄⁻ from aqueous solutions.

PubMed

Mahmoud, Mamdoh R; Seliman, Ayman F

2014-09-01

A novel mesoporous silica-coated ferrocyanide (MSCFC) composite was successfully synthesized and evaluated as a dual-function material for simultaneous removal of (137)Cs(+) cations and (99)TcO4(-) anions from aqueous solutions. Sorption behavior of both radionuclides on MSCFC under different experimental conditions has been studied using a batch technique. Results revealed that about 100% of (137)Cs(+) and 97% of (99)TcO4(-) were removed by MSCFC in the pH ranges of 2.2-12.4 and 4.1-9.5, respectively. Sorption kinetic data were analyzed by pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models, while Langmuir and Freundlich models were applied for the sorption isotherms. The maximum sorption capacity of MSCFC for radiocesium was determined and compared with other reported sorbents. Applicability of the coated ferrocyanide for simultaneous removal of (137)Cs(+) and (99)TcO4(-) from low-level liquid radioactive waste (LLLW) was also tested, and the data revealed that 99.91% and 98.34% were removed from (137)Cs(+) and (99)TcO4(-), respectively. It is concluded that MSCFC exhibits excellent efficiency for simultaneous removal of the mixed radionuclides with different charge from LLLW. Copyright © 2014 Elsevier Ltd. All rights reserved.

Material removal characteristics of orthogonal velocity polishing tool for efficient fabrication of CVD SiC mirror surfaces

NASA Astrophysics Data System (ADS)

Seo, Hyunju; Han, Jeong-Yeol; Kim, Sug-Whan; Seong, Sehyun; Yoon, Siyoung; Lee, Kyungmook; Lee, Haengbok

2015-09-01

Today, CVD SiC mirrors are readily available in the market. However, it is well known to the community that the key surface fabrication processes and, in particular, the material removal characteristics of the CVD SiC mirror surface varies sensitively depending on the shop floor polishing and figuring variables. We investigated the material removal characteristics of CVD SiC mirror surfaces using a new and patented polishing tool called orthogonal velocity tool (OVT) that employs two orthogonal velocity fields generated simultaneously during polishing and figuring machine runs. We built an in-house OVT machine and its operating principle allows for generation of pseudo Gaussian shapes of material removal from the target surface. The shapes are very similar to the tool influence functions (TIFs) of other polishing machine such as IRP series polishing machines from Zeeko. Using two CVD SiC mirrors of 150 mm in diameter and flat surface, we ran trial material removal experiments over the machine run parameter ranges from 12.901 to 25.867 psi in pressure, 0.086 m/sec to 0.147 m/sec in tool linear velocity, and 5 to 15 sec in dwell time. An in-house developed data analysis program was used to obtain a number of Gaussian shaped TIFs and the resulting material removal coefficient varies from 3.35 to 9.46 um/psi hour m/sec with the mean value to 5.90 ± 1.26(standard deviation). We report the technical details of the new OVT machine, of the data analysis program, of the experiments and the results together with the implications to the future development of the OVT machine and process for large CVD SiC mirror surfaces.

Experimental study of the thermal stability of materials in high temperature oxygen-containing media

NASA Technical Reports Server (NTRS)

Abaltusov, Y. Y.; Bagramyan, A. R.; Grishin, A. M.; Yukhvid, V. I.

1986-01-01

An experimental study is made of the interaction of several materials with a high temperature medium containing oxygen. The temperature of the surface was measured as a function of time. It is found that the higher the velocity of mass removal from the surface, the more effective is the material from the viewpoint of heat resistance.

Composition and method for removing photoresist materials from electronic components

DOEpatents

Davenhall, Leisa B.; Rubin, James B.

2002-01-01

The invention is a combination of at least one dense phase fluid and at least one dense phase fluid modifier which can be used to contact substrates for electronic parts such as semiconductor wafers or chips to remove photoresist materials which are applied to the substrates during manufacture of the electronic parts. The dense phase fluid modifier is one selected from the group of cyclic, aliphatic or alicyclic compounds having the functional group: ##STR1## wherein Y is a carbon, oxygen, nitrogen, phosphorus or sulfur atom or a hydrocarbon group having from 1 to 10 carbon atoms, a halogen or halogenated hydrocarbon group having from 1 to 10 carbon atoms, silicon or a fluorinated silicon group; and wherein R.sub.1 and R.sub.2 can be the same or different substituents; and wherein, as in the case where X is nitrogen, R.sub.1 or R.sub.2 may not be present. The invention compositions generally are applied to the substrates in a pulsed fashion in order to remove the hard baked photoresist material remaining on the surface of the substrate after removal of soft baked photoresist material and etching of the barrier layer.

An atomic-scale and high efficiency finishing method of zirconia ceramics by using magnetorheological finishing

NASA Astrophysics Data System (ADS)

Luo, Hu; Guo, Meijian; Yin, Shaohui; Chen, Fengjun; Huang, Shuai; Lu, Ange; Guo, Yuanfan

2018-06-01

Zirconia ceramics is a valuable crucial material for fabricating functional components applied in aerospace, biology, precision machinery, military industry and other fields. However, the properties of its high brittleness and high hardness could seriously reduce its finishing efficiency and surface quality by conventional processing technology. In this work, we present a high efficiency and high-quality finishing process by using magnetorheological finishing (MRF), which employs the permanent magnetic yoke with straight air gap as excitation unit. The sub-nanoscale surface roughness and damage free surface can be obtained after magnetorheological finishing. The XRD results and SEM morphologies confirmed that the mechanical shear removal with ductile modes are the dominant material removal mechanism for the magnetorheological finishing of zirconia ceramic. With the developed experimental apparatus, the effects of workpiece speed, trough speed and work gap on material removal rate and surface roughness were systematically investigated. Zirconia ceramics finished to ultra-smooth surface with surface roughness less than Ra 1 nm was repeatedly achieved during the parametric experiments. Additionally, the highest material removal rate exceeded 1 mg/min when using diamond as an abrasive particle. Magnetorheological finishing promises to be an adaptable and efficient method for zirconia ceramics finishing.

Design of Chitosan-Grafted Carbon Nanotubes: Evaluation of How the –OH Functional Group Affects Cs+ Adsorption

PubMed Central

Yang, Shubin; Shao, Dadong; Wang, Xiangke; Hou, Guangshun; Nagatsu, Masaaki; Tan, Xiaoli; Ren, Xuemei; Yu, Jitao

2015-01-01

In order to explore the effect of –OH functional groups in Cs+ adsorption, we herein used the low temperature plasma-induced grafting method to graft chitosan onto carbon nanotubes (denoted as CTS-g-CNTs), as raw-CNTs have few functional groups and chitosan has a large number of –OH functional groups. The synthesized CTS-g-CNT composites were characterized using different techniques. The effect of –OH functional groups in the Cs+ adsorption process was evaluated by comparison of the adsorption properties of raw-CNTs with and without grafting chitosan. The variation of environmental conditions such as pH and contact time was investigated. A comparison of contaminated seawater and simulated groundwater was also evaluated. The results indicated that: (1) the adsorption of Cs+ ions was strongly dependent on pH and the competitive cations; (2) for CNT-based material, the –OH functional groups have a positive effect on Cs+ removal; (3) simulated contaminated groundwater can be used to model contaminated seawater to evaluate the adsorption property of CNTs-based material. These results showed direct observational evidence on the effect of –OH functional groups for Cs+ adsorption. Our findings are important in providing future directions to design and to choose effective material to remedy the removal of radioactive cesium from contaminated groundwater and seawater, crucial for public health and the human social environment. PMID:26006711

One-step synthesis of water-dispersible cysteine functionalized magnetic Fe3O4 nanoparticles for mercury(II) removal from aqueous solutions

NASA Astrophysics Data System (ADS)

Shen, Xiaofang; Wang, Qin; Chen, WenLing; Pang, Yuehong

2014-10-01

Cysteine functionalized Fe3O4 magnetic nanoparticles (Cys-Fe3O4 MNPs) were prepared facilely for Hg(II) removal from aqueous solutions. Using Fe2+ as precursors, air as oxidant and Cys as protectant, this novel material was one-pot synthesis at room temperature by oxidation-precipitation method with the assistance of sonication. The MNPs were characterized by TEM, VSM, FTIR, X-ray powder diffraction analysis (XRD) and TGA methods. Under the optimum experimental conditions, the removal efficiency was as high as 95% and the maximum sorption capacity is found to be 380 mg/mol for Hg(II). Study on adsorption kinetics shows that adsorption of Hg(II) onto Cys-Fe3O4 MNPs follows pseudo-first-order kinetic model and the adsorption rate constant was 0.22 min-1. Additionally, the Hg(II)-loaded Cys-Fe3O4 MNPs could be easily regenerated up to 95% using 1.0 M acetic acid. These results indicated that Cys-Fe3O4 MNPs is a potentially attractive material for the removal of Hg(II) from water.

Aminopropyl-functionalized mesoporous carbon (APTMS-CMK-3) as effective phosphate adsorbent

NASA Astrophysics Data System (ADS)

Yang, Yanju; Wang, Juanjuan; Qian, Xiaoqing; Shan, Yuhua; Zhang, Haipeng

2018-01-01

Excess phosphate discharge into water bodies can lead to severe eutrophication. Adsorption has been considered as one of the most effective approaches for phosphate removal and recovery. A new aminopropyl-functionalized mesoporous carbon CMK-3 (denoted as APTMS-CMK-3) was prepared and the materials were used as adsorbents for the removal of phosphate in water. The structure, functional groups and surface charge of the materials were characterized by X-ray powder diffraction, transmission electron microscope, N2 adsorption-desorption, elemental analysis, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and zeta potential measurements. The effects of contact time, initial phosphate concentration, solution pH, coexisting anions and dissolved humic acid were studied. The adsorption capacity of APTMS-CMK-3 was 38.09 mg g-1 at the equilibrium concentration of 49.06 mg L-1, and the adsorption data were well fitted with the Freundlich model. As for the reuse of APTMS-CMK-3, a relatively stable adsorption performance was observed after five adsorption-desorption cycles. Therefore, the way of grafting aminopropyl groups on the CMK-3 efficiently enhanced the capability for phosphate adsorption, indicating that it could be used as potential adsorbents for the removal of phosphate in water.

Comparison of subsurface damages on mono-crystalline silicon between traditional nanoscale machining and laser-assisted nanoscale machining via molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Dai, Houfu; Li, Shaobo; Chen, Genyu

2018-01-01

Molecular dynamics is employed to compare nanoscale traditional machining (TM) with laser-assisted machining (LAM). LAM is that the workpiece is locally heated by an intense laser beam prior to material removal. We have a comprehensive comparison between LAM and TM in terms of atomic trajectories, phase transformation, radial distribution function, chips, temperature distribution, number of atoms in different temperature, grinding temperature, grinding force, friction coefficient and atomic potential energy. It can be found that there is a decrease of atoms with five and six nearest neighbors, and LAM generates more chips than that in the TM. It indicates that LAM reduces the subsurface damage of workpiece, gets a better-qualified ground surface and improves the material removal rate. Moreover, laser energy makes the materials fully softened before being removed, the number of atoms with temperature above 500 K is increased, and the average temperature of workpiece higher and faster to reach the equilibrium in LAM. It means that LAM has an absolute advantage in machining materials and greatly reduces the material resistance. Not only the tangential force (Fx) and the normal force (Fy) but also friction coefficients become smaller as laser heating reduces the strength and hardness of the material in LAM. These results show that LAM is a promising technique since it can get a better-qualified workpiece surface with larger material removal rates, less grinding force and lower friction coefficient.

Study on effect of the surface variation of colloidal silica abrasive during chemical mechanical polishing of sapphire

NASA Astrophysics Data System (ADS)

Bun-Athuek, Natthaphon; Yoshimoto, Yutaka; Sakai, Koya; Khajornrungruang, Panart; Suzuki, Keisuke

2017-07-01

The surface and diameter size variations of colloidal silica particles during the chemical mechanical polishing (CMP) of sapphire substrates were investigated using different particle diameters of 20 and 55 nm. Dynamic light scattering (DLS) results show that the silica particles became larger after CMP under both conditions. The increase in particle size in the slurry was proportional to the material removal amount (MRA) as a function of the removed volume of sapphire substrates by CMP and affected the material removal rate (MRR). Transmission electron microscopy (TEM) images revealed an increase in the size of the fine particles and a change in their surface shape in the slurry. The colloidal silica was coated with the material removed from the substrate during CMP. In this case, the increase in the size of 55 nm diameter particles is larger than that of 20 nm diameter particles. X-ray fluorescence spectrometry (XRF) results indicate that the aluminum element from polished sapphire substrates adhered to the surfaces of silica particles. Therefore, MRR decreases with increasing of polishing time owing to the degradation of particles in the slurry.

Thermally-isolated silicon-based integrated circuits and related methods

DOEpatents

Wojciechowski, Kenneth; Olsson, Roy H.; Clews, Peggy J.; Bauer, Todd

2017-05-09

Thermally isolated devices may be formed by performing a series of etches on a silicon-based substrate. As a result of the series of etches, silicon material may be removed from underneath a region of an integrated circuit (IC). The removal of the silicon material from underneath the IC forms a gap between remaining substrate and the integrated circuit, though the integrated circuit remains connected to the substrate via a support bar arrangement that suspends the integrated circuit over the substrate. The creation of this gap functions to release the device from the substrate and create a thermally-isolated integrated circuit.

Assessment of risk to Boeing commerical transport aircraft from carbon fibers. [fiber release from graphite/epxoy materials

NASA Technical Reports Server (NTRS)

Clarke, C. A.; Brown, E. L.

1980-01-01

The possible effects of free carbon fibers on aircraft avionic equipment operation, removal costs, and safety were investigated. Possible carbon fiber flow paths, flow rates, and transfer functions into the Boeing 707, 727, 737, 747 aircraft and potentially vulnerable equipment were identified. Probabilities of equipment removal and probabilities of aircraft exposure to carbon fiber were derived.

Functionalized Graphene Metal-Free Carbocatalysis of Persulfate and Emerging Contaminant Oxidative Degradation

NASA Astrophysics Data System (ADS)

Carroll, K. C.; Chen, H.

2016-12-01

We evaluated three types of functionalized, graphene-based materials for activating persulfate (PS) and removing (i.e., sorption and oxidation) sulfamethoxazole (SMX) as a model emerging contaminant. Although advanced oxidative water treatment requires PS activation, activation requires energy or chemical inputs, and toxic substances are contained in many catalysts. Graphene-based materials were examined herein as an alternative to metal-based catalysts. Results show that nitrogen-doped graphene (N-GP) and aminated graphene (NH2-GP) can effectively activate PS. Overall, PS activation by graphene oxide was not observed in this study. N-GP (50 mg L-1) can rapidly activate PS (1 mM) to remove >99.9% SMX within 3 hours, and NH2-GP (50 mg L-1) activated PS (1 mM) can also remove 50% SMX within 10 hours. SMX sorption and total removal was greater for N-GP, which suggests oxidation was enhanced by increasing proximity to PS activation sites. Increasing pH enhanced the N-GP catalytic ability, and >99.9% SMX removal time decreased from 3 hours to 1 hour when pH increased from 3 to 9. However, the PS catalytic ability was inhibited at pH 9 for NH2-GP. Increases in ionic strength (100 mM NaCl or Na2SO4) and addition of radical scavengers (500 mM ethanol) both had negligible impacts on SMX removal. With bicarbonate addition (100 mM), while the catalytic ability of N-GP remained unaltered, NH2-GP catalytic ability was inhibited completely. Humic acid (250 mg L-1) was partially effective in inhibiting SMX removal in both N-GP and NH2-GP systems. These results have implications for elucidating oxidant catalysis mechanisms, and they quantify the ability of functionalization of graphene with hetero-atom doping to effectively catalyze PS for water treatment of organic pollutants including emerging contaminants.

Static tool influence function for fabrication simulation of hexagonal mirror segments for extremely large telescopes.

PubMed

Kim, Dae Wook; Kim, Sug-Whan

2005-02-07

We present a novel simulation technique that offers efficient mass fabrication strategies for 2m class hexagonal mirror segments of extremely large telescopes. As the first of two studies in series, we establish the theoretical basis of the tool influence function (TIF) for precessing tool polishing simulation for non-rotating workpieces. These theoretical TIFs were then used to confirm the reproducibility of the material removal foot-prints (measured TIFs) of the bulged precessing tooling reported elsewhere. This is followed by the reverse-computation technique that traces, employing the simplex search method, the real polishing pressure from the empirical TIF. The technical details, together with the results and implications described here, provide the theoretical tool for material removal essential to the successful polishing simulation which will be reported in the second study.

Performance evaluation of a slow-release packing material-embedded functional microorganisms for biofiltration.

PubMed

Zhu, Rencheng; Li, Shunyi; Wu, Zhenjun; Dumont, Éric

2017-04-01

A composite packing material (CM-5) was prepared in this study, mainly consisting of compost with functional microorganisms, calcium carbonate (CaCO 3 ), perlite, cement and plant fiber. To get stronger compressive strength, mass ratios of these components were optimized based on single factor experiments, and finally adding amounts of perlite, cement, plant fiber, CaCO 3 , compost and binder at 18%, 18%, 7%, 13%, 17% and 27%, respectively. According to the optimum proportion, CM-5 was extruded in cylindrical shape (12 mm in diameter and 20 mm in length) with a bulk density of 470 kg m -3 , a moisture retention capacity of 49% and the microbial counts of × 10 5 CFU g -1 of packing material. The cumulative release rates of total organic carbon (TOC) and total nitrogen (TN) from CM-5 were 3.1% and 6.5%, respectively, after 19 times extraction in distilled water. To evaluate the H 2 S removal capacity, CM-5 was compared with an organic (corncob) and an inorganic (ceramsite) packing material in three biofilters. The results showed that CM-5 had higher H 2 S removal capacity compared with corncob and ceramsite. CM-5 could avoid the large fluctuation of pH value and pressure drop during the operation. The maximum H 2 S removal capacity of CM-5 was 12.9 g m -3  h -1 and the removal efficiency could maintain over 95.4% when the inlet H 2 S loading rate was lower than 11.3 g m -3  h -1 without any addition of nutrients and pH buffer substances. Besides, only 2-3 days were needed for the recovery of biofiltration performance after about two weeks of idle period.

Auto-recognition of surfaces and auto-generation of material removal volume for finishing process

NASA Astrophysics Data System (ADS)

Kataraki, Pramod S.; Salman Abu Mansor, Mohd

2018-03-01

Auto-recognition of a surface and auto-generation of material removal volumes for the so recognised surfaces has become a need to achieve successful downstream manufacturing activities like automated process planning and scheduling. Few researchers have contributed to generation of material removal volume for a product but resulted in material removal volume discontinuity between two adjacent material removal volumes generated from two adjacent faces that form convex geometry. The need for limitation free material removal volume generation was attempted and an algorithm that automatically recognises computer aided design (CAD) model’s surface and also auto-generate material removal volume for finishing process of the recognised surfaces was developed. The surfaces of CAD model are successfully recognised by the developed algorithm and required material removal volume is obtained. The material removal volume discontinuity limitation that occurred in fewer studies is eliminated.

Investigation of contact pressure and influence function model for soft wheel polishing.

PubMed

Rao, Zhimin; Guo, Bing; Zhao, Qingliang

2015-09-20

The tool influence function (TIF) is critical for calculating the dwell-time map to improve form accuracy. We present the TIF for the process of computer-controlled polishing with a soft polishing wheel. In this paper, the static TIF was developed based on the Preston equation. The pressure distribution was verified by the real removal spot section profiles. According to the experiment measurements, the pressure distribution simulated by Hertz contact theory was much larger than the real contact pressure. The simulated pressure distribution, which was modeled by the Winkler elastic foundation for a soft polishing wheel, matched the real contact pressure. A series of experiments was conducted to obtain the removal spot statistical properties for validating the relationship between material removal and processing time and contact pressure and relative velocity, along with calculating the fitted parameters to establish the TIF. The developed TIF predicted the removal character for the studied soft wheel polishing.

Ion Figuring of Replicated X-Ray Optics

NASA Technical Reports Server (NTRS)

Cantey, Thomas M.; Gregory, Don A.

1997-01-01

This investigation included experiments to demonstrate ion beam figuring effects on electroless nickel with the expressed desire to figure X-ray optic mandrels. It was important to establish that ion beam figuring did not induce any adverse effects to the nickel surface. The ion beam has consistently been shown to be an excellent indicator of the quality of the subsurface. Polishing is not the only cause for failure in the ion beam final figuring process, the material composition is equally important. Only by careful consideration of both these factors can the ion beam final figuring process achieve its greatest potential. The secondary goal was to construct a model for representing the ion beam material removal rate. Representing the ion beam removal rate is only an approximation and has a number of limiting factors. The resolution of the metrology apparatus limits the modeling of the beam function as well. As the surface error corrections demand more precision in the final figuring, the model representing beam function must be equally precise. The precision to which the beam function can be represented is not only determined by the model but also by the measurements producing that model. The method developed for determining the beam function has broad application to any material destined to be ion beam figured.

Chemistry and Formation of the Beilby Layer During Polishing of Fused Silica Glass

DOE PAGES

Suratwala, Tayyab; Steele, William; Wong, Lana; ...

2015-05-19

The chemical characteristics and the proposed formation mechanisms of the modified surface layer (called the Beilby layer) on polished fused silica glasses are described. Fused silica glass samples were polished using different slurries, polyurethane pads, and at different rotation rates. The concentration profiles of several key contaminants, such as Ce, K, and H, were measured in the near surface layer of the polished samples using Secondary Ion Mass Spectroscopy (SIMS). The penetration of K, originating from KOH used for pH control during polishing, decreased with increase in polishing material removal rate. In contrast, penetration of the Ce and H increasedmore » with increase in polishing removal rate. In addition, Ce penetration was largely independent of the other polishing parameters (e.g., particle size distribution and the properties of the polishing pad). The resulting K concentration depth profiles are described using a two-step diffusion process: (1) steady-state moving boundary diffusion (due to material removal during polishing) followed by (2) simple diffusion during ambient postpolishing storage. Using known alkali metal diffusion coefficients in fused silica glass, this diffusion model predicts concentration profiles that are consistent with the measured data at various polishing material removal rates. On the other hand, the observed Ce profiles are inconsistent with diffusion based transport. Rather we propose that Ce penetration is governed by the ratio of Ce–O–Si and Si–O–Si hydrolysis rates; where this ratio increases with interface temperature (which increases with polishing material removal rate) resulting in greater Ce penetration into the Beilby layer. Calculated Ce surface concentrations using this mechanism are in good agreement to the observed change in measured Ce surface concentrations with polishing material removal rate. In conclusion, these new insights into the chemistry of the Beilby layer, combined together with details of the single particle removal function during polishing, are used to develop a more detailed and quantitative picture of the polishing process and the formation of the Beilby layer.« less

Fabrication of the tea saponin functionalized reduced graphene oxide for fast adsorptive removal of Cd(II) from water

NASA Astrophysics Data System (ADS)

Li, Zhigang; Liu, Zhifeng; Wu, Zhibin; Zeng, Guangming; Shao, Binbin; Liu, Yujie; Jiang, Yilin; Zhong, Hua; Liu, Yang

2018-05-01

A novel graphene-based material of tea saponin functionalized reduced graphene oxide (TS-RGO) was synthesized via a facil thermal method, and it was characterized as the absorbent for Cd(II) removal from aqueous solutions. The factors on adsorption process including solution pH, contact time, initial concentration of Cd(II) and background electrolyte cations were studied to optimize the conditions for maximum adsorption at room temperature. The results indicated that Cd(II) adsorption was strongly dependent on pH and could be strongly affected by background electrolytes and ionic strength. The optimal pH and required equilibrium time was 6.0 and 10 min, respectively. The Cd(II) removal decreased with the presence of background electrolyte cations (Na+ < Ca2+ < Al3+). The adsorption kinetics of Cd(II) followed well with the pseudo-second-order model. The adsorption isotherm fitted well to the Langmuir model, indicating that the adsorption was a monolayer adsorption process occurred on the homogeneous surfaces of TS-RGO. The maximum monolayer adsorption capacity was 127 mg/g at 313 K and pH 6.0. Therefore, the TS-RGO was considered to be a cost-effective and promising material for the removal of Cd(II) from wastewater.

Novel mixed matrix membranes for sulfur removal and for fuel cell applications

NASA Astrophysics Data System (ADS)

Lin, Ligang; Wang, Andong; Zhang, Longhui; Dong, Meimei; Zhang, Yuzhong

2012-12-01

Sulfur removal is significant for fuels used as hydrogen source for fuel cell applications and to avoid sulfur poisoning of therein used catalysts. Novel mixed matrix membranes (MMMs) with well-defined transport channels are proposed for sulfur removal. MMMs are fabricated using polyimide (PI) as matrix material and Y zeolites as adsorptive functional materials. The influence of architecture conditions on the morphology transition from finger-like to sponge-like structure and the “short circuit” effect are investigated. The adsorption and regeneration behavior of MMMs is discussed, combining the detailed analysis of FT-IR, morphology, XPS, XRD and thermal properties of MMMs, the process-structure-function relationship is obtained. The results show that the functional zeolites are incorporated into three-dimensional network and the adsorption capacity of MMMs comes to 8.6 and 9.5 mg S g-1 for thiophene and dibenzothiophene species, respectively. And the regeneration behavior suggests that the spent membranes can recover about 88% and 96% of the desulfurization capacity by solvent washing and thermal treating regeneration, respectively. The related discussions provide some general suggestions in promoting the novel application of MMMs on the separation of organic-organic mixtures, and a potential alternative for the production of sulfur-free hydrogen source for fuel cell applications.

The influence of reaction time on hydrogen sulphide removal from air by means of Fe(III)-EDTA/Fiban catalysts

NASA Astrophysics Data System (ADS)

Wasag, H.; Cel, W.; Chomczynska, M.; Kujawska, J.

2018-05-01

The paper deals with a new method of hydrogen sulphide removal from air by its filtration and selective catalytic oxidation with the use of fibrous carriers of Fe(III)-EDTA complex. The basis of these filtering materials includes fibrous ion exchangers with the complex immobilized on their functional groups. It has been established that the degree of catalytic hydrogen sulphide decomposition depends on the reaction time. Thus, the required degree of hydrogen sulphide removal from air could be easily controlled by applying appropriate thickness of the filtering layer under a given filtering velocity. It allows applying very thin filtering layers of the Fe(III)-EDTA/Fiban AK-22 or Fiban A-6 catalysts. The obtained results of the research confirm the applicability of these materials for deep air purification from hydrogen sulphide.

Effects of temperature on the removal efficiency of KDP crystal during the process of magnetorheological water-dissolution polishing.

PubMed

Zhang, Yifan; Dai, Yifan; Tie, Guipeng; Hu, Hao

2016-10-10

As a kind of important nonlinear optical element, KDP crystal has great demand in the inertial confinement fusion system. Based on the dissolution mechanism of solid materials, the factors that affect the material removal rate of KDP crystal in magnetorheological (MR) water-dissolution polishing are investigated to improve the machining efficiency. It is found that the material removal rate is proportional to the product of the saturation concentration and diffusion coefficient, and the relationship between the removal efficiency and the temperature meets the unilateral Gaussian function. Polishing experiments are carried out on a magnetorheological finishing (MRF) machine with self-designed MRF fluid heating devices. The experimental results show that practical efficiency-temperature curve is consistent with the theoretical curve, and the maximum machining efficiency increases by about 50% with the rise of temperature from 294 to 302 K. Meanwhile, when the MR fluid temperature is lower than 308 K, the crystal surface quality and surface roughness in different processing temperatures have no remarkable difference with constant crystal temperature (294 K). This research indicates that it is feasible to drastically improve KDP crystal MRF efficiency by controlling the processing temperature.

Spatially orthogonal chemical functionalization of a hierarchical pore network for catalytic cascade reactions

NASA Astrophysics Data System (ADS)

Parlett, Christopher M. A.; Isaacs, Mark A.; Beaumont, Simon K.; Bingham, Laura M.; Hondow, Nicole S.; Wilson, Karen; Lee, Adam F.

2016-02-01

The chemical functionality within porous architectures dictates their performance as heterogeneous catalysts; however, synthetic routes to control the spatial distribution of individual functions within porous solids are limited. Here we report the fabrication of spatially orthogonal bifunctional porous catalysts, through the stepwise template removal and chemical functionalization of an interconnected silica framework. Selective removal of polystyrene nanosphere templates from a lyotropic liquid crystal-templated silica sol-gel matrix, followed by extraction of the liquid crystal template, affords a hierarchical macroporous-mesoporous architecture. Decoupling of the individual template extractions allows independent functionalization of macropore and mesopore networks on the basis of chemical and/or size specificity. Spatial compartmentalization of, and directed molecular transport between, chemical functionalities affords control over the reaction sequence in catalytic cascades; herein illustrated by the Pd/Pt-catalysed oxidation of cinnamyl alcohol to cinnamic acid. We anticipate that our methodology will prompt further design of multifunctional materials comprising spatially compartmentalized functions.

Pyridinium-functionalized magnetic mesoporous silica nanoparticles as a reusable adsorbent for phosphate removal from aqueous solution.

PubMed

Ma, Fang; Du, Hongtao; Li, Ronghua; Zhang, Zengqiang

In this work, pyridinium-functionalized silica nanoparticles adsorbent (PC/SiO2/Fe3O4) was synthesized for phosphate removal from aqueous solutions. The removal efficiency of phosphate on the PC/SiO2/Fe3O4 was carried out and investigated under various conditions such as pH, contact temperature and initial concentration. The results showed that the adsorption equilibrium could be reached within 10 min, which fitted a Langmuir isotherm model, with maximum adsorption capacity of 94.16 mg/g, and the kinetic data were fitted well by pseudo-second-order and intra-particle diffusion models. Phosphate loaded on the adsorbents could be easily desorbed with 0.2 mol/L of NaOH, and the adsorbents showed good reusability. The adsorption capacity was still around 50 mg/g after 10 times of reuse. All the results demonstrated that this pyridinium-functionalized mesoporous material could be used for the phosphate removal from aqueous solution and it was easy to collect due to its magnetic properties.

Variation of yield loci in finite element analysis by considering texture evolution for AA5042 aluminum sheets

NASA Astrophysics Data System (ADS)

Yoon, Jonghun; Kim, Kyungjin; Yoon, Jeong Whan

2013-12-01

Yield function has various material parameters that describe how materials respond plastically in given conditions. However, a significant number of mechanical tests are required to identify the many material parameters for yield function. In this study, an effective method using crystal plasticity through a virtual experiment is introduced to develop the anisotropic yield function for AA5042. The crystal plasticity approach was used to predict the anisotropic response of the material in order to consider a number of stress or strain modes that would not otherwise be evident through mechanical testing. A rate-independent crystal plasticity model based on a smooth single crystal yield surface, which removes the innate ambiguity problem within the rate-independent model and Taylor model for polycrystalline deformation behavior were employed to predict the material's response in the balanced biaxial stress, pure shear, and plane strain states to identify the parameters for the anisotropic yield function of AA5042.

Experimental performance of an ablative material as an external insulator for a hypersonic research aircraft

NASA Technical Reports Server (NTRS)

Puster, R. L.; Chapman, A. J.

1977-01-01

An ablative material composed of silica-filled elastomeric silicone was tested to evaluate its thermal and structural performance as an external insulator, or heat shield, for a hypersonic research aircraft. The material was also tested to determine whether it would form a durable char layer when initially heated and thereafter function primarily as an insulator with little further pyrolysis or char removal. Aerothermal tests were representative of nominal Mach 6 cruise conditions of the aircraft, and additional tests were representative of Mach 8 cruise and interference heating conditions. Radiant heating tests were used to simulate the complete nominal Mach 6 surface-temperature history. The silica char that formed during aerothermal tests was not durable. The char experienced a general and preferential surface recession, with the primary mechanism for char removal being erosion. Tests revealed that radiant heating is not a valid technique for simulating aerodynamic heating of the material.

Chlorine dioxide reactions with indoor materials during building disinfection: surface uptake.

PubMed

Hubbard, Heidi; Poppendieck, Dustin; Corsi, Richard L

2009-03-01

Chlorine dioxide received attention as a building disinfectant in the wake of Bacillus anthracis contamination of several large buildings in the fall of 2001. It is increasingly used for the disinfection of homes and other indoor environments afflicted by mold. However, little is known regarding the interaction of chlorine dioxide and indoor materials, particularly as related to the removal of chlorine dioxide from air. Such removal may be undesirable with respect to the subsequent formation of localized zones of depleted disinfectant concentrations and potential reductions in disinfection effectiveness in a building. The focus of this paper is on chlorine dioxide removal from air to each of 24 different indoor materials. Experiments were completed with materials housed in flow-through 48-L stainless steel chambers under standard conditions of 700 ppm chlorine dioxide inlet concentration, 75% relative humidity, 24 degrees C, and 0.5 h(-1) air changes. Chlorine dioxide concentration profiles, deposition velocities, and reaction probabilities are described in this paper. Deposition velocities and reaction probabilities varied over approximately 2 orders of magnitude across all materials. For most materials, deposition velocity decreased significantly over a 16-h disinfection period; that is, materials became smaller sinks for chlorine dioxide with time. Four materials (office partition, ceiling tile, medium density fiberboard, and gypsum wallboard) accounted for the most short- and long-term consumption of chlorine dioxide. Deposition velocity was observed to be a strong function of chlorine dioxide inlet concentration, suggesting the potential importance of chemical reactions on or within test materials.

Method and system for radioisotope generation

DOEpatents

Toth, James J.; Soderquist, Chuck Z.; Greenwood, Lawrence R.; Mattigod, Shas V.; Fryxell, Glen E.; O'Hara, Matthew J.

2014-07-15

A system and a process for producing selected isotopic daughter products from parent materials characterized by the steps of loading the parent material upon a sorbent having a functional group configured to selectively bind the parent material under designated conditions, generating the selected isotopic daughter products, and eluting said selected isotopic daughter products from the sorbent. In one embodiment, the process also includes the step of passing an eluent formed by the elution step through a second sorbent material that is configured to remove a preselected material from said eluent. In some applications a passage of the material through a third sorbent material after passage through the second sorbent material is also performed.

a Study on the Effect of Annealing Process on Sound Velocity and Internal Friction Using the Vibrating Reed Technique

NASA Astrophysics Data System (ADS)

Mukhopadhyay, P. K.; Kumar, Uday; Badawi, Emad

Al has unique intrinsic characteristics, which are of interest to scientists as well as engineers. Al and its alloys are slightly paramagnetic materials. Al has very low cross section for thermal neutrons of 0.23 barn, hence Al can be used in nuclear fields as a structural material which is virtually transparent to neutrons. We report VRT as a new technique to study material problems. We also discuss, the results of sound velocity and internal friction, and resonance frequency as a function of temperature range for a pure aluminum sample under investigation. By using VRT, we found that the annealing temperature (450°C) is sufficient to remove the type of defects introduced in the materials under study. The activation energy to remove point defect for Al samples was calculated and found to be about 0.0624 eV. Also, we could easily observe that Q-1 is a function of annealing time. From these measurements of sound velocity and internal friction we can conclude that VRT is a powerful tool for detecting and probing the physical properties of the material under study. Internal friction is a microscopic property for the indication of the purity of the sample. Sound velocity depends on the state of the materials (which depends on the process of treatment).

Molecular receptors in metal oxide sol-gel materials prepared via molecular imprinting

DOEpatents

Sasaki, Darryl Y.; Brinker, C. Jeffrey; Ashley, Carol S.; Daitch, Charles E.; Shea, Kenneth J.; Rush, Daniel J.

2000-01-01

A method is provided for molecularly imprinting the surface of a sol-gel material, by forming a solution comprised of a sol-gel material, a solvent, an imprinting molecule, and a functionalizing siloxane monomer of the form Si(OR).sub.3-n X.sub.n, wherein n is an integer between zero and three and X is a functional group capable of reacting with the imprinting molecule, evaporating the solvent, and removing the imprinting molecule to form the molecularly imprinted metal oxide sol-gel material. The use of metal oxide sol-gels allows the material porosity, pore size, density, surface area, hardness, electrostatic charge, polarity, optical density, and surface hydrophobicity to be tailored and be employed as sensors and in catalytic and separations operations.

Compensating for velocity truncation during subaperture polishing by controllable and time-variant tool influence functions.

PubMed

Dong, Zhichao; Cheng, Haobo; Tam, Hon-Yuen

2015-02-10

The velocity-varying regime used in deterministic subaperture polishing employs a time-invariant tool influence function (TIF) to figure localized surface errors by varying the transverse velocities of polishing tools. Desired transverse velocities have to be truncated if they exceed the maximal velocity of computer numerical control (CNC) machines, which induces excessive material removal and reduces figuring efficiency (FE). A time-variant (TV) TIF regime is presented, in which a TIF serves as a variable to compensate for excessive material removal when the transverse velocities are truncated. Compared with other methods, the TV-TIF regime exhibits better performance in terms of convergence rate, FE, and versatility; its operability can also be strengthened by a TIF library. Comparative experiments were conducted on a magnetorheological finishing machine to validate the effectiveness of the TV-TIF regime. Without a TV-TIF, the tool made an unwished dent (depth of 76 nm) at the center because of the velocity truncation problem. Through compensation with a TV-TIF, the dent was completely removed by the second figuring process, and a TV-TIF improved the FE from 0.029 to 0.066  mm(3)/h.

Development of cost-effective noncarbon sorbents for Hg(0) removal from coal-fired power plants.

PubMed

Lee, Joo-Youp; Ju, Yuhong; Keener, Tim C; Varma, Rajender S

2006-04-15

Noncarbonaceous materials or mineral oxides (silica gel, alumina, molecular sieves, zeolites, and montmorillonite) were modified with various functional groups such as amine, amide, thiol, urea, and active additives such as elemental sulfur, sodium sulfide, and sodium polysulfide to examine their potential as sorbents for the removal of elemental mercury (Hg(0)) vapor at coal-fired utility power plants. A number of sorbent candidates such as amine- silica gel, urea- silica gel, thiol- silica gel, amide-silica gel, sulfur-alumina, sulfur-molecular sieve, sulfur-montmorillonite, sodium sulfide-montmorillonite, and sodium polysulfide-montmorillonite, were synthesized and tested in a lab-scale fixed-bed system under an argon flow for screening purposes at 70 degrees C and/or 140 degrees C. Several functionalized silica materials reported in previous studies to effectively control heavy metals in the aqueous phase showed insignificant adsorption capacities for Hg(0) control in the gas phase, suggesting that mercury removal mechanisms in both phases are different. Among elemental sulfur-, sodium sulfide-, and sodium polysulfide-impregnated inorganic samples, sodium polysulfide-impregnated montmorillonite K 10 showed a moderate adsorption capacity at 70 degrees C, which can be used for sorbent injection prior to the wet FGD system.

Algorithm for ion beam figuring of low-gradient mirrors.

PubMed

Jiao, Changjun; Li, Shengyi; Xie, Xuhui

2009-07-20

Ion beam figuring technology for low-gradient mirrors is discussed. Ion beam figuring is a noncontact machining technique in which a beam of high-energy ions is directed toward a target workpiece to remove material in a predetermined and controlled fashion. Owing to this noncontact mode of material removal, problems associated with tool wear and edge effects, which are common in conventional contact polishing processes, are avoided. Based on the Bayesian principle, an iterative dwell time algorithm for planar mirrors is deduced from the computer-controlled optical surfacing (CCOS) principle. With the properties of the removal function, the shaping process of low-gradient mirrors can be approximated by the linear model for planar mirrors. With these discussions, the error surface figuring technology for low-gradient mirrors with a linear path is set up. With the near-Gaussian property of the removal function, the figuring process with a spiral path can be described by the conventional linear CCOS principle, and a Bayesian-based iterative algorithm can be used to deconvolute the dwell time. Moreover, the selection criterion of the spiral parameter is given. Ion beam figuring technology with a spiral scan path based on these methods can be used to figure mirrors with non-axis-symmetrical errors. Experiments on SiC chemical vapor deposition planar and Zerodur paraboloid samples are made, and the final surface errors are all below 1/100 lambda.

Deterministic Computer-Controlled Polishing Process for High-Energy X-Ray Optics

NASA Technical Reports Server (NTRS)

Khan, Gufran S.; Gubarev, Mikhail; Speegle, Chet; Ramsey, Brian

2010-01-01

A deterministic computer-controlled polishing process for large X-ray mirror mandrels is presented. Using tool s influence function and material removal rate extracted from polishing experiments, design considerations of polishing laps and optimized operating parameters are discussed

Chemical, biological, radiological, and nuclear decontamination: Recent trends and future perspective

PubMed Central

Kumar, Vinod; Goel, Rajeev; Chawla, Raman; Silambarasan, M.; Sharma, Rakesh Kumar

2010-01-01

Chemical, biological, radiological, and nuclear (CBRN) decontamination is the removal of CBRN material from equipment or humans. The objective of the decontamination is to reduce radiation burden, salvage equipment, and materials, remove loose CBRN contaminants, and fix the remaining in place in preparation for protective storage or permanent disposal work activities. Decontamination may be carried out using chemical, electrochemical, and mechanical means. Like materials, humans may also be contaminated with CBRN contamination. Changes in cellular function can occur at lower radiation doses and exposure to chemicals. At high dose, cell death may take place. Therefore, decontamination of humans at the time of emergency while generating bare minimum waste is an enormous task requiring dedication of large number of personnel and large amount of time. General principles of CBRN decontamination are discussed in this review with emphasis on radiodecontamination. PMID:21829318

Arsenic Adsorption from Water Using Graphene-Based Materials as Adsorbents: a Critical Review

NASA Astrophysics Data System (ADS)

Yang, Xuetong; Xia, Ling; Song, Shaoxian

2017-07-01

Adsorption is widely applied to remove arsenic from water. This paper reviewed and compared the recent progresses on the arsenic removal by adsorption using two-dimensional and three-dimensional graphene-based materials as adsorbents. Functional graphene sheet achieved the largest As(III) adsorption capacity of 138.79mg/g, while Mg-Al LDH/GO2 showed the largest As(V) adsorption capacity of 183.11mg/g. Parameters including pH, temperature, co-existing ions and loaded metal or metal oxide affected the adsorption process. The adsorption mechanisms of graphene-based materials for As(III) and As(V) could be explained by surface complexation and the electrostatic attraction, respectively. Future works are suggested to focus on regenerating of two-dimensional graphene-based adsorbents and developing the three-dimensional with large specific surface area and better adsorption performance.

Adsorptive Removal of Pharmaceuticals and Personal Care Products from Water with Functionalized Metal-organic Frameworks: Remarkable Adsorbents with Hydrogen-bonding Abilities.

PubMed

Seo, Pill Won; Bhadra, Biswa Nath; Ahmed, Imteaz; Khan, Nazmul Abedin; Jhung, Sung Hwa

2016-10-03

Adsorption of typical pharmaceuticals and personal care products (PPCPs) (such as naproxen, ibuprofen and oxybenzone) from aqueous solutions was studied by using the highly porous metal-organic framework (MOF) MIL-101 with and without functionalization. Adsorption results showed that MIL-101s with H-donor functional groups such as -OH and -NH 2 were very effective for naproxen adsorption, despite a decrease in porosity, probably because of H-bonding between O atoms on naproxen and H atoms on the adsorbent. For this reason, MIL-101 with two functional groups capable of H-bonding (MIL-101-(OH) 2 ) exhibited remarkable adsorption capacity based on adsorbent surface area. The favorable contributions of -OH and -(OH) 2 on MIL-101 in the increased adsorption of ibuprofen and oxybenzone (especially based on porosity) confirmed again the importance of H-bonding mechanism. The adsorbent with the highest adsorption capacity, MIL-101-OH, was very competitive when compared with carbonaceous materials, mesoporous materials, and pristine MIL-101. Moreover, the MIL-101-OH could be recycled several times by simply washing with ethanol, suggesting potential application in the adsorptive removal of PPCPs from water.

Adsorptive Removal of Pharmaceuticals and Personal Care Products from Water with Functionalized Metal-organic Frameworks: Remarkable Adsorbents with Hydrogen-bonding Abilities

NASA Astrophysics Data System (ADS)

Seo, Pill Won; Bhadra, Biswa Nath; Ahmed, Imteaz; Khan, Nazmul Abedin; Jhung, Sung Hwa

2016-10-01

Adsorption of typical pharmaceuticals and personal care products (PPCPs) (such as naproxen, ibuprofen and oxybenzone) from aqueous solutions was studied by using the highly porous metal-organic framework (MOF) MIL-101 with and without functionalization. Adsorption results showed that MIL-101s with H-donor functional groups such as -OH and -NH2 were very effective for naproxen adsorption, despite a decrease in porosity, probably because of H-bonding between O atoms on naproxen and H atoms on the adsorbent. For this reason, MIL-101 with two functional groups capable of H-bonding (MIL-101-(OH)2) exhibited remarkable adsorption capacity based on adsorbent surface area. The favorable contributions of -OH and -(OH)2 on MIL-101 in the increased adsorption of ibuprofen and oxybenzone (especially based on porosity) confirmed again the importance of H-bonding mechanism. The adsorbent with the highest adsorption capacity, MIL-101-OH, was very competitive when compared with carbonaceous materials, mesoporous materials, and pristine MIL-101. Moreover, the MIL-101-OH could be recycled several times by simply washing with ethanol, suggesting potential application in the adsorptive removal of PPCPs from water.

Adsorptive Removal of Pharmaceuticals and Personal Care Products from Water with Functionalized Metal-organic Frameworks: Remarkable Adsorbents with Hydrogen-bonding Abilities

PubMed Central

Seo, Pill Won; Bhadra, Biswa Nath; Ahmed, Imteaz; Khan, Nazmul Abedin; Jhung, Sung Hwa

2016-01-01

Adsorption of typical pharmaceuticals and personal care products (PPCPs) (such as naproxen, ibuprofen and oxybenzone) from aqueous solutions was studied by using the highly porous metal-organic framework (MOF) MIL-101 with and without functionalization. Adsorption results showed that MIL-101s with H-donor functional groups such as –OH and –NH2 were very effective for naproxen adsorption, despite a decrease in porosity, probably because of H-bonding between O atoms on naproxen and H atoms on the adsorbent. For this reason, MIL-101 with two functional groups capable of H-bonding (MIL-101-(OH)2) exhibited remarkable adsorption capacity based on adsorbent surface area. The favorable contributions of –OH and –(OH)2 on MIL-101 in the increased adsorption of ibuprofen and oxybenzone (especially based on porosity) confirmed again the importance of H-bonding mechanism. The adsorbent with the highest adsorption capacity, MIL-101-OH, was very competitive when compared with carbonaceous materials, mesoporous materials, and pristine MIL-101. Moreover, the MIL-101-OH could be recycled several times by simply washing with ethanol, suggesting potential application in the adsorptive removal of PPCPs from water. PMID:27695005

Floating treatment wetlands for domestic wastewater treatment.

PubMed

Faulwetter, J L; Burr, M D; Cunningham, A B; Stewart, F M; Camper, A K; Stein, O R

2011-01-01

Floating islands are a form of treatment wetland characterized by a mat of synthetic matrix at the water surface into which macrophytes can be planted and through which water passes. We evaluated two matrix materials for treating domestic wastewater, recycled plastic and recycled carpet fibers, for chemical oxygen demand (COD) and nitrogen removal. These materials were compared to pea gravel or open water (control). Experiments were conducted in laboratory scale columns fed with synthetic wastewater containing COD, organic and inorganic nitrogen, and mineral salts. Columns were unplanted, naturally inoculated, and operated in batch mode with continuous recirculation and aeration. COD was efficiently removed in all systems examined (>90% removal). Ammonia was efficiently removed by nitrification. Removal of total dissolved N was ∼50% by day 28, by which time most remaining nitrogen was present as NO(3)-N. Complete removal of NO(3)-N by denitrification was accomplished by dosing columns with molasses. Microbial communities of interest were visualized with denaturing gradient gel electrophoresis (DGGE) by targeting specific functional genes. Shifts in the denitrifying community were observed post-molasses addition, when nitrate levels decreased. The conditioning time for reliable nitrification was determined to be approximately three months. These results suggest that floating treatment wetlands are a viable alternative for domestic wastewater treatment.

Discrimination of tooth layers and dental restorative materials using cutting sounds.

PubMed

Zakeri, Vahid; Arzanpour, Siamak; Chehroudi, Babak

2015-03-01

Dental restoration begins with removing carries and affected tissues with air-turbine rotary cutting handpieces, and later restoring the lost tissues with appropriate restorative materials to retain the functionality. Most restoration materials eventually fail as they age and need to be replaced. One of the difficulties in replacing failing restorations is discerning the boundary of restorative materials, which causes inadvertent removal of healthy tooth layers. Developing an objective and sensor-based method is a promising approach to monitor dental restorative operations and to prevent excessive tooth losses. This paper has analyzed cutting sounds of an air-turbine handpiece to discriminate between tooth layers and two commonly used restorative materials, amalgam and composite. Support vector machines were employed for classification, and the averaged short-time Fourier transform coefficients were selected as the features. The classifier performance was evaluated from different aspects such as the number of features, feature scaling methods, classification schemes, and utilized kernels. The total classification accuracies were 89% and 92% for cases included composite and amalgam materials, respectively. The obtained results indicated the feasibility and effectiveness of the proposed method.

DEVELOPMENT OF NONCARBON SORBENTS FOR HG0 REMOVAL FROM COAL-FIRED POWER PLANTS

EPA Science Inventory

Noncarbon materials or mineral oxides (silica gel, alumina, molecular sieves, zeolites, and montmorillonite) were modified with various functional groups, such as amine, amide, thiol, and urea; and active additives, such as elemental sulfur, sodium sulfide, and sodium polysulfide...

Correlation of impression removal force with elastomeric impression material rigidity and hardness.

PubMed

Walker, Mary P; Alderman, Nick; Petrie, Cynthia S; Melander, Jennifer; McGuire, Jacob

2013-07-01

Difficult impression removal has been linked to high rigidity and hardness of elastomeric impression materials. In response to this concern, manufacturers have reformulated their materials to reduce rigidity and hardness to decrease removal difficulty; however, the relationship between impression removal and rigidity or hardness has not been evaluated. The purpose of this study was to determine if there is a positive correlation between impression removal difficulty and rigidity or hardness of current elastomeric impression materials. Light- and medium-body polyether (PE), vinylpolysiloxane (VPS), and hybrid vinyl polyether siloxane (VPES) impression materials were tested (n = 5 for each material/consistency/test method). Rigidity (elastic modulus) was measured via tensile testing of dumbbell-shaped specimens (Die C, ASTM D412). Shore A hardness was measured using disc specimens according to ASTM D2240-05 test specifications. Impressions were also made of a custom stainless steel model using a custom metal tray that could be attached to a universal tester to measure associated removal force. Within each impression material consistency, one-factor ANOVA and Tukey's post hoc analyses (α = 0.05) were used to compare rigidity, hardness, and removal force of the three types of impression materials. A Pearson's correlation (α = 0.05) was used to evaluate the association between impression removal force and rigidity or hardness. With medium-body materials, VPS exhibited significantly higher (p ≤ 0.05) rigidity and hardness than VPES or PE, while PE impressions required significantly higher (p ≤ 0.05) removal force than VPS or VPES impressions. With light-body materials, VPS again demonstrated significantly higher (p ≤ 0.05) hardness than VPES or PE, while the rigidity of the light-body materials did not significantly differ between materials (p > 0.05); however, just as with the medium-body materials, light-body PE impressions required significantly higher (p ≤ 0.05) removal force than VPS or VPES. Moreover, there was no positive correlation (p > 0.05) between impression removal force and rigidity or hardness with either medium- or light-body materials. The evidence suggests that high impression material rigidity and hardness are not predictors of impression removal difficulty. © 2013 by the American College of Prosthodontists.

Spot breeding method to evaluate the determinism of magnetorheological finishing

NASA Astrophysics Data System (ADS)

Yang, Hang; He, Jianguo; Huang, Wen; Zhang, Yunfei

2017-03-01

The influences of immersion depth of magnetorheological finishing (MRF) on the shape and material removal rate (MRR) of removal function are theoretically investigated to establish the spot transition mechanism. Based on this mechanism, for the first time, the spot breeding method to predict the shape and removal rate of MRF spot is proposed. The UBK7 optical parts are polished to verify the proposed method on experimental installation PKC-1000Q2 developed by ourselves. The experimental results reveal that the predictions of shape and MRR with this method are precise. The proposed method provides a basis for analyzing the determinism of MRF due to geometry of the process.

Kinematical and mechanical aspects of wafer slicing

NASA Technical Reports Server (NTRS)

Werner, P. G.

1982-01-01

Some recently achieved results concerning the technological fundamentals of slurry sawing are presented. The specific material removal process and the related kinematic and geometric contact conditions between workpiece and saw blade are described. The result of a functional description of the slurry sawing process is presented, expressing the main process criteria, such as infeed per stroke, specific removal rate, specific tool wear, and vertical stroke intensity, in terms of the dominating process parameters, such as stroke length, width of workpiece, stroke frequency, specific cutting force and slurry specification.

Modification of Chitin with Kraft Lignin and Development of New Biosorbents for Removal of Cadmium(II) and Nickel(II) Ions

PubMed Central

Wysokowski, Marcin; Klapiszewski, Łukasz; Moszyński, Dariusz; Bartczak, Przemysław; Szatkowski, Tomasz; Majchrzak, Izabela; Siwińska-Stefańska, Katarzyna; Bazhenov, Vasilii V.; Jesionowski, Teofil

2014-01-01

Novel, functional materials based on chitin of marine origin and lignin were prepared. The synthesized materials were subjected to physicochemical, dispersive-morphological and electrokinetic analysis. The results confirm the effectiveness of the proposed method of synthesis of functional chitin/lignin materials. Mechanism of chitin modification by lignin is based on formation of hydrogen bonds between chitin and lignin. Additionally, the chitin/lignin materials were studied from the perspective of waste water treatment. The synthetic method presented in this work shows an attractive and facile route for producing low-cost chitin/lignin biosorbents with high efficiency of nickel and cadmium adsorption (88.0% and 98.4%, respectively). The discovery of this facile method of synthesis of functional chitin/lignin materials will also have a significant impact on the problematic issue of the utilization of chitinous waste from the seafood industry, as well as lignin by-products from the pulp and paper industry. PMID:24727394

Extraction of palm tree cellulose and its functionalization via graft copolymerization.

PubMed

Al-Hoqbani, Abdulmajeed A; Abdel-Halim, E S; Al-Deyab, Salem S

2014-09-01

The work in this paper was planned with the aim of extracting the cellulosic component of palm tree waste and functionalizing this cellulose through graft copolymerization with acrylic acid. The cellulose extraction included hot alkali treatment with aqueous sodium hydroxide to remove the non-cellulosic binding materials. The alkali treatment was followed by an oxidative bleaching using peracid/hydrogen peroxide mixture with the aim of removing the rest of non-cellulosic materials to improve the fiber hydrophilicity and accessibility towards further grafting reaction. Optimum conditions for cellulose extraction are boiling in 5% (W/V) NaOH in a material to liquor ratio of 1:20 for 1 h then bleaching with 60 ml/l bleaching mixture at initial pH value of 6.5 for 30 min. The pH of the bleaching medium is turned to the alkaline range 11 and bleaching continues for extra 30 min. Graft copolymerization reaction was initiated by potassium bromate/thiourea dioxide redox system. Optimum conditions for grafting are 30 mmol of potassium bromate, 30 mmol of thiourea dioxide and 150 g of acrylic acid (each per 100 g of cellulose). The polymerization reaction was carried out for 120 min at 50°C using a material to liquor ratio of 1:20. Copyright © 2014 Elsevier B.V. All rights reserved.

Ultrasonic Abrasive Removal Of EDM Recast

NASA Technical Reports Server (NTRS)

Mandel, Johnny L.; Jacobson, Marlowe S.

1990-01-01

Ultrasonic abrasive process removes layer of recast material generated during electrical-discharge machining (EDM) of damper pocket on turbine blade. Form-fitted tool vibrated ultrasonically in damper pocket from which material removed. Vibrations activate abrasive in pocket. Amount of material removed controlled precisely.

Property-process relations in simulated clinical abrasive adjusting of dental ceramics.

PubMed

Yin, Ling

2012-12-01

This paper reports on property-process correlations in simulated clinical abrasive adjusting of a wide range of dental restorative ceramics using a dental handpiece and diamond burs. The seven materials studied included four mica-containing glass ceramics, a feldspathic porcelain, a glass-infiltrated alumina, and a yttria-stabilized tetragonal zirconia. The abrasive adjusting process was conducted under simulated clinical conditions using diamond burs and a clinical dental handpiece. An attempt was made to establish correlations between process characteristics in terms of removal rate, chipping damage, and surface finish and material mechanical properties of hardness, fracture toughness and Young's modulus. The results show that the removal rate is mainly a function of hardness, which decreases nonlinearly with hardness. No correlations were noted between the removal rates and the complex relations of hardness, Young's modulus and fracture toughness. Surface roughness was primarily a linear function of diamond grit size and was relatively independent of materials. Chipping damage in terms of the average chipping width decreased with fracture toughness except for glass-infiltrated alumina. It also had higher linear correlations with critical strain energy release rates (R²=0.66) and brittleness (R²=0.62) and a lower linear correlation with indices of brittleness (R²=0.32). Implications of these results can provide guidance for the microstructural design of dental ceramics, optimize performance, and guide the proper selection of technical parameters in clinical abrasive adjusting conducted by dental practitioners. Copyright © 2012 Elsevier Ltd. All rights reserved.

Photo-Curable Metal-Chelating Coatings Offer a Scalable Approach to Production of Antioxidant Active Packaging.

PubMed

Lin, Zhuangsheng; Goddard, Julie

2018-02-01

Synthetic metal chelators (for example, ethylenediaminetetraacetic acid, EDTA) are widely used as additives to control trace transition metal induced oxidation in consumer products. To enable removal of synthetic chelators in response to increasing consumer demand for clean label products, metal-chelating active food packaging technologies have been developed with demonstrated antioxidant efficacy in simulated food systems. However, prior work in fabrication of metal-chelating materials leveraged batch chemical reactions to tether metal-chelating ligands, a process with limited industrial translatability for large-scale fabrication. To improve the industrial translatability, we have designed a 2-step laminated photo-grafting process to introduce metal chelating functionality onto common polymeric packaging materials. Iminodiacetic acid (IDA) functionalized materials were fabricated by photo-grafting poly(acrylic acid) onto polypropylene (PP) films, followed by a second photo-grafting process to graft-polymerize an IDA functionalized vinyl monomer (GMA-IDA). The photo-grafting was conducted under atmospheric conditions and was completed in 2 min. The resulting IDA functionalized metal-chelating material was able to chelate iron and copper, and showed antioxidant efficacy against ascorbic acid degradation, supporting its potential to be used synergistically with natural antioxidants for preservation of food and beverage products. The 2-step photo-grafting process improves the throughput of active packaging coatings, enabling potential roll-to-roll fabrication of metal-chelating active packaging materials for antioxidant food packaging applications. To address consumer and retail demands for "clean label" foods and beverages without a corresponding loss in product quality and shelf life, producers are seeking next generation technologies such as active packaging. In this work, we will report the synthesis of metal-chelating active packaging films, which enable removal of the synthetic additive, ethylenediamine tetraacetic acid. The new synthesis technique improves the throughput of metal-chelating active packaging coatings, enabling potential roll-to-roll fabrication of the materials for antioxidant food packaging applications. © 2018 Institute of Food Technologists®.

Biochar-based nano-composites for the decontamination of wastewater: A review.

PubMed

Tan, Xiao-Fei; Liu, Yun-Guo; Gu, Yan-Ling; Xu, Yan; Zeng, Guang-Ming; Hu, Xin-Jiang; Liu, Shao-Bo; Wang, Xin; Liu, Si-Mian; Li, Jiang

2016-07-01

Synthesizing biochar-based nano-composites can obtain new composites and combine the advantages of biochar with nano-materials. The resulting composites usually exhibit great improvement in functional groups, pore properties, surface active sites, catalytic degradation ability and easy to separation. These composites have excellent abilities to adsorb a range of contaminants from aqueous solutions. Particularly, catalytic material-coated biochar can exert simultaneous adsorption and catalytic degradation function for organic contaminants removal. Synthesizing biochar-based nano-composites has become an important practice for expanding the environmental applications of biochar and nanotechnology. This paper aims to review and summarize the various synthesis techniques for biochar-based nano-composites and their effects on the decontamination of wastewater. The characteristic and advantages of existing synthesis methods are summarized and discussed. Application of biochar-based nano-composites for different contaminants removal and the underlying mechanisms are reviewed. Furthermore, knowledge gaps that exist in the fabrication and application of biochar-based nano-composites are also identified. Copyright © 2016 Elsevier Ltd. All rights reserved.

On the closed form mechanistic modeling of milling: Specific cutting energy, torque, and power

NASA Astrophysics Data System (ADS)

Bayoumi, A. E.; Yücesan, G.; Hutton, D. V.

1994-02-01

Specific energy in metal cutting, defined as the energy expended in removing a unit volume of workpiece material, is formulated and determined using a previously developed closed form mechanistic force model for milling operations. Cutting power is computed from the cutting torque, cutting force, kinematics of the cutter, and the volumetric material removal rate. Closed form expressions for specific cutting energy were formulated and found to be functions of the process parameters: pressure and friction for both rake and flank surfaces and chip flow angle at the rake face of the tool. Friction is found to play a very important role in cutting torque and power. Experiments were carried out to determine the effects of feedrate, cutting speed, workpiece material, and flank wear land width on specific cutting energy. It was found that the specific cutting energy increases with a decrease in the chip thickness and with an increase in flank wear land.

Modelling of the acid-base properties of natural and synthetic adsorbent materials used for heavy metal removal from aqueous solutions.

PubMed

Pagnanelli, Francesca; Vegliò, Francesco; Toro, Luigi

2004-02-01

In this paper a comparison about kinetic behaviour, acid-base properties and copper removal capacities was carried out between two different adsorbent materials used for heavy metal removal from aqueous solutions: an aminodiacetic chelating resin as commercial product (Lewatit TP207) and a lyophilised bacterial biomass of Sphaerotilus natans. The acid-base properties of a S. natans cell suspension were well described by simplified mechanistic models without electrostatic corrections considering two kinds of weakly acidic active sites. In particular the introduction of two-peak distribution function for the proton affinity constants allows a better representation of the experimental data reproducing the site heterogeneity. A priori knowledge about resin functional groups (aminodiacetic groups) is the base for preliminary simulations of titration curve assuming a Donnan gel structure for the resin phase considered as a concentrated aqueous solution of aminodiacetic acid (ADA). Departures from experimental and simulated data can be interpreted by considering the heterogeneity of the functional groups and the effect of ionic concentration in the resin phase. Two-site continuous model describes adequately the experimental data. Moreover the values of apparent protonation constants (as adjustable parameters found by non-linear regression) are very near to the apparent constants evaluated by a Donnan model assuming the intrinsic constants in resin phase equal to the equilibrium constants in aqueous solution of ADA and considering the amphoteric nature of active sites for the evaluation of counter-ion concentration in the resin phase. Copper removal outlined the strong affinity of the active groups of the resin for this ion in solution compared to the S. natans biomass according to the complexation constants between aminodiacetic and mono-carboxylic groups and copper ions.

Adsorption of methyl orange by synthesized and functionalized-CNTs with 3-aminopropyltriethoxysilane loaded TiO2 nanocomposites.

PubMed

Ahmad, Amirah; Razali, Mohd Hasmizam; Mamat, Mazidah; Mehamod, Faizatul Shimal Binti; Anuar Mat Amin, Khairul

2017-02-01

This study aims to develop a highly efficient adsorbent material. CNTs are prepared using a chemical vapor deposition method with acetylene and synthesized mesoporous Ni-MCM41 as the carbon source and catalyst, respectively, and are then functionalized using 3-aminopropyltriethoxysilane (APTES) through the co-condensation method and loaded with commercial TiO 2 . Results of X-ray powder diffraction (XRD), Raman spectra, and Fourier transform infrared spectroscopy (FTIR) confirm that the synthesized CNTs grown are multi-walled carbon nanotubes (MWNTs). Transmission electron microscopy shows good dispersion of TiO 2 nanoparticles onto functionalized-CNTs loaded TiO 2 , with the diameter of a hair-like structure measuring between 3 and 8 nm. The functionalized-CNTs loaded TiO 2 are tested as an adsorbent for removal of methyl orange (MO) in aqueous solution, and results show that 94% of MO is removed after 10 min of reaction, and 100% after 30 min. The adsorption kinetic model of functionalized-CNTs loaded TiO 2 follows a pseudo-second order with a maximum adsorption capacity of 42.85 mg/g. This study shows that functionalized-CNTs loaded TiO 2 has considerable potential as an adsorbent material due to the short adsorption time required to achieve equilibrium. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adsorption of Antibiotics on Graphene and Biochar in Aqueous Solutions Induced by π-π Interactions

PubMed Central

Peng, Bingquan; Chen, Liang; Que, Chenjing; Yang, Ke; Deng, Fei; Deng, Xiaoyong; Shi, Guosheng; Xu, Gang; Wu, Minghong

2016-01-01

The use of carbon based materials on the removal of antibiotics with high concentrations has been well studied, however the effect of this removal method is not clear on the actual concentration of environments, such as the hospital wastewater, sewage treatment plants and aquaculture wastewater. In this study, experimental studies on the adsorption of 7 antibiotics in environmental concentration of aqueous solutions by carbon based materials have been observed. Three kinds of carbon materials have shown very fast adsorption to antibiotics by liquid chromatography–tandem mass spectrometry (LC-MS-MS) detection, and the highest removal efficiency of antibiotics could reach to 100% within the range of detection limit. Surprisedly, the adsorption rate of graphene with small specific surface area was stronger than other two biochar, and adsorption rate of the two biochar which have approximate specific surface and different carbonization degree, was significantly different. The key point to the present observation were the π-π interactions between aromatic rings on adsorbed substance and carbon based materials by confocal laser scanning microscope observation. Moreover, adsorption energy markedly increased with increasing number of the π rings by using the density functional theory (DFT), showing the particular importance of π-π interactions in the adsorption process. PMID:27534975

Biosorption of heavy metal ions using wheat based biosorbents--a review of the recent literature.

PubMed

Farooq, Umar; Kozinski, Janusz A; Khan, Misbahul Ain; Athar, Makshoof

2010-07-01

Conventional technologies for the removal/remediation of toxic metal ions from wastewaters are proving expensive due to non-regenerable materials used and high costs. Biosorption is emerging as a technique offering the use of economical alternate biological materials for the purpose. Functional groups like carboxyl, hydroxyl, sulphydryl and amido present in these biomaterials, make it possible for them to attach metal ions from waters. Every year, large amounts of straw and bran from Triticum aestivum (wheat), a major food crop of the world, are produced as by-products/waste materials. The purpose of this article is to review rather scattered information on the utilization of straw and bran for the removal/minimization of metal ions from waters. High efficiency, high biosorption capacity, cost-effectiveness and renewability are the important parameters making these materials as economical alternatives for metal removal and waste remediation. Applications of available adsorption and kinetic models as well as influences of change in temperature and pH of medium on metal biosorption by wheat straw and wheat bran are reviewed. The biosorption mechanism has been found to be quite complex. It comprises a number of phenomena including adsorption, surface precipitation, ion-exchange and complexation. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Adsorption of Antibiotics on Graphene and Biochar in Aqueous Solutions Induced by π-π Interactions

NASA Astrophysics Data System (ADS)

Peng, Bingquan; Chen, Liang; Que, Chenjing; Yang, Ke; Deng, Fei; Deng, Xiaoyong; Shi, Guosheng; Xu, Gang; Wu, Minghong

2016-08-01

The use of carbon based materials on the removal of antibiotics with high concentrations has been well studied, however the effect of this removal method is not clear on the actual concentration of environments, such as the hospital wastewater, sewage treatment plants and aquaculture wastewater. In this study, experimental studies on the adsorption of 7 antibiotics in environmental concentration of aqueous solutions by carbon based materials have been observed. Three kinds of carbon materials have shown very fast adsorption to antibiotics by liquid chromatography-tandem mass spectrometry (LC-MS-MS) detection, and the highest removal efficiency of antibiotics could reach to 100% within the range of detection limit. Surprisedly, the adsorption rate of graphene with small specific surface area was stronger than other two biochar, and adsorption rate of the two biochar which have approximate specific surface and different carbonization degree, was significantly different. The key point to the present observation were the π-π interactions between aromatic rings on adsorbed substance and carbon based materials by confocal laser scanning microscope observation. Moreover, adsorption energy markedly increased with increasing number of the π rings by using the density functional theory (DFT), showing the particular importance of π-π interactions in the adsorption process.

Retrieval of Mir Solar Array

NASA Technical Reports Server (NTRS)

Rutledge, Sharon K.; deGroh, Kim K.

1999-01-01

A Russian solar array panel removed in November 1997 from the non-articulating photovoltaic array on the Mir core module was returned to Earth on STS-89 in January 1998. The panel had been exposed to low Earth orbit (LEO) for 10 years prior to retrieval. The retrieval provided a unique opportunity to study the effects of the LEO environment on a functional solar array. To take advantage of this opportunity, a team composed of members from RSC-Energia (Russia), the Boeing Company, and the following NASA Centers--Johnson Space Center, Kennedy Space Center, Langley Research Center, Marshall Space Flight Center, and Lewis Research Center--was put together to analyze the array. After post-retrieval inspections at the Spacehab Facility at Kennedy in Florida, the array was shipped to Lewis in Cleveland for electrical performance tests, closeup photodocumentation, and removal of selected solar cells and blanket material. With approval from RSC-Energia, five cell pairs and their accompanying blanket and mesh material, and samples of painted handrail materials were selected for removal on the basis of their ability to provide degradation information. Sites were selected that provided different sizes and shapes of micrometeoroid impacts and different levels of surface contamination. These materials were then distributed among the team for round robin testing.

A review of functionalized carbon nanotubes and graphene for heavy metal adsorption from water: Preparation, application, and mechanism.

PubMed

Xu, Jiang; Cao, Zhen; Zhang, Yilin; Yuan, Zilin; Lou, Zimo; Xu, Xinhua; Wang, Xiangke

2018-03-01

Carbon-based nanomaterials, especially carbon nanotubes and graphene, have drawn wide attention in recent years as novel materials for environmental applications. Notably, the functionalized derivatives of carbon nanotubes and graphene with high surface area and adsorption sites are proposed to remove heavy metals via adsorption, addressing the pressing pollution of heavy metal. This critical revies assesses the recent development of various functionalized carbon nanotubes and graphene that are used to remove heavy metals from contaminated water, including the preparation and characterization methods of functionalized carbon nanotubes and graphene, their applications for heavy metal adsorption, effects of water chemistry on the adsorption capacity, and decontamination mechanism. Future research directions have also been proposed with the goal of further improving their adsorption performance, the feasibility of industrial applications, and better simulating adsorption mechanisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Computed tomography assessment of the efficiency of different techniques for removal of root canal filling material.

PubMed

Dall'Agnol, Cristina; Hartmann, Mateus Silveira Martins; Barletta, Fernando Branco

2008-01-01

This study evaluated the efficiency of different techniques for removal of filling material from root canals, using computed tomography (CT). Sixty mesial roots from extracted human mandibular molars were used. Root canals were filled and, after 6 months, the teeth were randomly assigned to 3 groups, according to the root-filling removal technique: Group A - hand instrumentation with K-type files; Group B - reciprocating instrumentation with engine-driven K-type files; and Group C rotary instrumentation with engine-driven ProTaper system. CT scans were used to assess the volume of filling material inside the root canals before and after the removal procedure. In both moments, the area of filling material was outlined by an experienced radiologist and the volume of filling material was automatically calculated by the CT software program. Based on the volume of initial and residual filling material of each specimen, the percentage of filling material removed from the root canals by the different techniques was calculated. Data were analyzed statistically by ANOVA and chi-square test for linear trend (?=0.05). No statistically significant difference (p=0.36) was found among the groups regarding the percent means of removed filling material. The analysis of the association between the percentage of filling material removal (high or low) and the proposed techniques by chi-square test showed statistically significant difference (p=0.015), as most cases in group B (reciprocating technique) presented less than 50% of filling material removed (low percent removal). In conclusion, none of the techniques evaluated in this study was effective in providing complete removal of filling material from the root canals.

Solid amine development program

NASA Technical Reports Server (NTRS)

Lovell, J. S.

1973-01-01

A regenerable solid amine material to perform the functions of humidity control and CO2 removal for space shuttle type vehicle is reported. Both small scale and large scale testing have shown this material to be competitive, especially for the longer shuttle missions. However, it had been observed that the material off-gasses ammonia under certain conditions. This presents two concerns. The first, that the ammonia would contaminate the cabin atmosphere, and second, that the material is degrading with time. An extensive test program has shown HS-C to produce only trace quantities of atmospheric contaminants, and under normal extremes, to have no practical life limitation.

Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent.

PubMed

Awual, Md Rabiul; Yaita, Tsuyoshi; Taguchi, Tomitsugu; Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro

2014-08-15

Conjugate materials can provide chemical functionality, enabling an assembly of the ligand complexation ability to metal ions that are important for applications, such as separation and removal devices. In this study, we developed ligand immobilized conjugate adsorbent for selective cesium (Cs) removal from wastewater. The adsorbent was synthesized by direct immobilization of dibenzo-24-crown-8 ether onto inorganic mesoporous silica. The effective parameters such as solution pH, contact time, initial Cs concentration and ionic strength of Na and K ion concentrations were evaluated and optimized systematically. This adsorbent was exhibited the high surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Cs. The obtained results revealed that adsorbent had higher selectivity toward Cs even in the presence of a high concentration of Na and K and this is probably due to the Cs-π interaction of the benzene ring. The proposed adsorbent was successfully applied for radioactive Cs removal to be used as the potential candidate in Fukushima nuclear wastewater treatment. The adsorbed Cs was eluted with suitable eluent and simultaneously regenerated into the initial form for the next removal operation after rinsing with water. The adsorbent retained functionality despite several cycles during sorption-elution-regeneration operations. Copyright © 2014 Elsevier B.V. All rights reserved.

Graphene Emerges as a Versatile Template for Materials Preparation.

PubMed

Li, Zhengjie; Wu, Sida; Lv, Wei; Shao, Jiao-Jing; Kang, Feiyu; Yang, Quan-Hong

2016-05-01

Graphene and its derivatives are emerging as a class of novel but versatile templates for the controlled preparation and functionalization of materials. In this paper a conceptual review on graphene-based templates is given, highlighting their versatile roles in materials preparation. Graphene is capable of acting as a low-dimensional hard template, where its two-dimensional morphology directs the formation of novel nanostructures. Graphene oxide and other functionalized graphenes are amphiphilic and may be seen as soft templates for formatting the growth or inducing the controlled assembly of nanostructures. In addition, nanospaces in restacked graphene can be used for confining the growth of sheet-like nanostructures, and assemblies of interlinked graphenes can behave either as skeletons for the formation of composite materials or as sacrificial templates for novel materials with a controlled network structure. In summary, flexible graphene and its derivatives together with an increasing number of assembled structures show great potentials as templates for materials production. Many challenges remain, for example precise structural control of such novel templates and the removal of the non-functional remaining templates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Athermal brittle-to-ductile transition in amorphous solids.

PubMed

Dauchot, Olivier; Karmakar, Smarajit; Procaccia, Itamar; Zylberg, Jacques

2011-10-01

Brittle materials exhibit sharp dynamical fractures when meeting Griffith's criterion, whereas ductile materials blunt a sharp crack by plastic responses. Upon continuous pulling, ductile materials exhibit a necking instability that is dominated by a plastic flow. Usually one discusses the brittle to ductile transition as a function of increasing temperature. We introduce an athermal brittle to ductile transition as a function of the cutoff length of the interparticle potential. On the basis of extensive numerical simulations of the response to pulling the material boundaries at a constant speed we offer an explanation of the onset of ductility via the increase in the density of plastic modes as a function of the potential cutoff length. Finally we can resolve an old riddle: In experiments brittle materials can be strained under grip boundary conditions and exhibit a dynamic crack when cut with a sufficiently long initial slot. Mysteriously, in molecular dynamics simulations it appeared that cracks refused to propagate dynamically under grip boundary conditions, and continuous pulling was necessary to achieve fracture. We argue that this mystery is removed when one understands the distinction between brittle and ductile athermal amorphous materials.

40 CFR 63.9631 - What are my monitoring requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... maintain a bag leak detection system to monitor the relative change in particulate matter loadings... of ensuring the proper functioning of removal mechanisms. (3) Check the compressed air supply of... interior for air leaks. (8) Inspect fans for wear, material buildup, and corrosion through quarterly visual...

Edge control in a computer controlled optical surfacing process using a heterocercal tool influence function.

PubMed

Hu, Haixiang; Zhang, Xin; Ford, Virginia; Luo, Xiao; Qi, Erhui; Zeng, Xuefeng; Zhang, Xuejun

2016-11-14

Edge effect is regarded as one of the most difficult technical issues in a computer controlled optical surfacing (CCOS) process. Traditional opticians have to even up the consequences of the two following cases. Operating CCOS in a large overhang condition affects the accuracy of material removal, while in a small overhang condition, it achieves a more accurate performance, but leaves a narrow rolled-up edge, which takes time and effort to remove. In order to control the edge residuals in the latter case, we present a new concept of the 'heterocercal' tool influence function (TIF). Generated from compound motion equipment, this type of TIF can 'transfer' the material removal from the inner place to the edge, meanwhile maintaining the high accuracy and efficiency of CCOS. We call it the 'heterocercal' TIF, because of the inspiration from the heterocercal tails of sharks, whose upper lobe provides most of the explosive power. The heterocercal TIF was theoretically analyzed, and physically realized in CCOS facilities. Experimental and simulation results showed good agreement. It enables significant control of the edge effect and convergence of entire surface errors in large tool-to-mirror size-ratio conditions. This improvement will largely help manufacturing efficiency in some extremely large optical system projects, like the tertiary mirror of the Thirty Meter Telescope.

Efficient removal of methyl orange using Cu2O as a dual function catalyst

NASA Astrophysics Data System (ADS)

Zhang, Fan; Dong, Guohui; Wang, Mian; Zeng, Yubin; Wang, Chuanyi

2018-06-01

In this study, we synthesized Cu2O particles with rough surfaces by a facile solvothermal method as a dual-function material that can degrade contaminants not only under light irradiation but also in dark circumstance. Both the as-prepared Cu2O and commercial Cu2O exhibited excellent performance for the removal of methyl orange under visible light irradiation through a photocatalysis-based strategy. However, the former was found to show remarkable capability under dark circumstances by means of molecular oxygen activation, while the latter performed poor efficiently under the same condition. This significant difference of performances under dark circumstances was related to rich oxygen vacancies existed on the as-prepared Cu2O surfaces that are associated with the single-electron reduction of O2 to generate radO2-, which play a dominant role in the generation of Cu+. In addition, Cu+ was identified to play key roles in the broken of azo bond. Then, the generated intermediates were mineralized by radOH generated through molecular oxygen activation process. This study could not only deep the understanding of the MO removal mechanism by Cu2O but also show a novel direction of amphibious application for photocatalytic materials.

Designer carbon nanotubes for contaminant removal in water and wastewater: A critical review.

PubMed

Sarkar, Binoy; Mandal, Sanchita; Tsang, Yiu Fai; Kumar, Pawan; Kim, Ki-Hyun; Ok, Yong Sik

2018-01-15

The search for effective materials for environmental cleanup is a scientific and technological issue of paramount importance. Among various materials, carbon nanotubes (CNTs) possess unique physicochemical, electrical, and mechanical properties that make them suitable for potential applications as environmental adsorbents, sensors, membranes, and catalysts. Depending on the intended application and the chemical nature of the target contaminants, CNTs can be designed through specific functionalization or modification processes. Designer CNTs can remarkably enhance contaminant removal efficiency and facilitate nanomaterial recovery and regeneration. An increasing number of CNT-based materials have been used to treat diverse organic, inorganic, and biological contaminants. These success stories demonstrate their strong potential in practical applications, including wastewater purification and desalination. However, CNT-based technologies have not been broadly accepted for commercial use due to their prohibitive cost and the complex interactions of CNTs with other abiotic and biotic environmental components. This paper presents a critical review of the existing literature on the interaction of various contaminants with CNTs in water and soil environments. The preparation methods of various designer CNTs (surface functionalized and/or modified) and the functional relationships between their physicochemical characteristics and environmental uses are discussed. This review will also help to identify the research gaps that must be addressed for enhancing the commercial acceptance of CNTs in the environmental remediation industry. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of fiber material on ozone removal and carbonyl production from carpets

NASA Astrophysics Data System (ADS)

Abbass, Omed A.; Sailor, David J.; Gall, Elliott T.

2017-01-01

Indoor air quality is affected by indoor materials such as carpets that may act as sources and/or sinks of gas-phase air pollutants. Heterogeneous reactions of ozone with carpets may result in potentially harmful products. In this study, indoor residential carpets of varying fiber types were tested to evaluate their ability to remove ozone, and to assess their role in the production of carbonyls when exposed to elevated levels of ozone. Tests were conducted with six types of new unused carpets. Two sets of experiments were conducted, the first measured ozone removal and ozone deposition velocities, and the second measured primary carbonyl production and secondary production as a result of exposure to ozone. The tests were conducted using glass chambers with volume of 52 L each. Air exchange rates for all tests were 3 h-1. The ozone removal tests show that, for the conditions tested, the polyester carpet sample had the lowest ozone removal (40%), while wool carpet had the greatest ozone removal (65%). Most carpet samples showed higher secondary than primary carbonyl emissions, with carpets containing polypropylene fibers being a notable exception. Carpets with polyester fibers had both the highest primary and secondary emissions of formaldehyde among all samples tested. While it is difficult to make blanket conclusions about the relative air quality merits of various carpet fiber options, it is clear that ozone removal percentages and emissions of volatile organic compounds can vary drastically as a function of fiber type.

Nanomanufacturing of silicon surface with a single atomic layer precision via mechanochemical reactions.

PubMed

Chen, Lei; Wen, Jialin; Zhang, Peng; Yu, Bingjun; Chen, Cheng; Ma, Tianbao; Lu, Xinchun; Kim, Seong H; Qian, Linmao

2018-04-18

Topographic nanomanufacturing with a depth precision down to atomic dimension is of importance for advancement of nanoelectronics with new functionalities. Here we demonstrate a mask-less and chemical-free nanolithography process for regio-specific removal of atomic layers on a single crystalline silicon surface via shear-induced mechanochemical reactions. Since chemical reactions involve only the topmost atomic layer exposed at the interface, the removal of a single atomic layer is possible and the crystalline lattice beneath the processed area remains intact without subsurface structural damages. Molecular dynamics simulations depict the atom-by-atom removal process, where the first atomic layer is removed preferentially through the formation and dissociation of interfacial bridge bonds. Based on the parametric thresholds needed for single atomic layer removal, the critical energy barrier for water-assisted mechanochemical dissociation of Si-Si bonds was determined. The mechanochemical nanolithography method demonstrated here could be extended to nanofabrication of other crystalline materials.

Virus removal by unsaturated wastewater filtration: effects of biofilm accumulation and hydrophobicity.

PubMed

Heistad, A; Scott, T; Skaarer, A M; Seidu, R; Hanssen, J F; Stenström, T A

2009-01-01

Enhanced treatment of septic tank effluent can improve the hydraulic function and performance of infiltration systems and constructed wetlands. By intermittent spray application of septic tank effluent onto a coarse-grained filter media, an unsaturated flow regime beneficial for pathogen removal is created. A column filtration study showed an increase in PRD-1 removal by time of operation with corresponding biofilm accumulation in the filter material. The same increased removal was observed for 1 mum polystyrene beads, irrespective of their hydrophilic/hydrophobic surface properties. A control experiment with sorption of 1 mum hydrophobic and hydrophilic polystyrene beads to different glass surfaces with hydrophobic and hydrophilic properties indicate that mechanisms other than hydrophobic interactions may govern the rate of attachment to the filter media. For a given volumetric flow-rate in the columns, the presence of biofilm altered the hydrodynamic characteristics and this resulted in increased retention time and particle removal.

Assessment of Filter Materials for Removal of Contaminants From Agricultural Drainage Waters

NASA Astrophysics Data System (ADS)

Allred, B. J.

2007-12-01

Fertilizer nutrients and pesticides applied on farm fields, especially in the Midwest U.S., are commonly intercepted by buried agricultural drainage pipes and then discharged into local streams and lakes, oftentimes resulting in an adverse environmental impact on these surface water bodies. Low cost filter materials have the potential to remove nutrient and pesticide contaminants from agricultural drainage waters before these waters are released from the farm site. Batch tests were conducted to find filter materials potentially capable of removing nutrient (nitrate and phosphate) and pesticide (atrazine) contaminants from subsurface drainage waters. For each batch test, stock solution (40 g) and filter material (5 g) were combined in 50 mL Teflon centrifuge tubes and mixed with a rotator for 24 hours. The stock solution contained 50 mg/L nitrate-N, 0.25 mg/L phosphate-P, 0.4 mg/L atrazine, 570 mg/L calcium sulfate, and 140 mg/L potassium chloride. Calcium sulfate and potassium chloride were added so that the stock solution would contain anions and cations normally found in agricultural drainage waters. There were six replicate batch tests for each filter material. At the completion of each test, solution was removed from the centrifuge tube and analyzed for nitrate-N, phosphate-P, and atrazine. A total of 38 filter materials were tested, which were divided into five classes; high carbon content substances, high iron content substances, high aluminum content substances, surfactant modified clay/zeolite, and coal combustion products. Batch test results generally indicate, that with regard to the five classes of filter materials; high carbon content substances adsorbed atrazine very effectively; high iron content substances worked especially well removing almost all of the phosphate present; high aluminum content substances lowered phosphate levels; surfactant modified clay/zeolite substantially reduced both nitrate and atrazine; and coal combustion products significantly decreased phosphate amounts. For the 38 specific filter materials evaluated, based on a 60 percent contaminant reduction level, 12 materials removed nitrate, 26 materials removed phosphate, and 21 materials removed atrazine. Furthermore, 2 materials removed zero contaminants, 16 materials removed one contaminant, 17 materials removed two contaminants, and 3 of the materials removed all three contaminants. The most effective filter materials proved to be a steam activated carbon, a zero valent iron and sulfer modified iron mixture, and a surfactant modified clay. The findings of this study indicate that there are a variety of filter materials, either separately or in combination, which have the potential to treat agricultural drainage waters.

Direct micropatterning of polymer materials by ice mold

NASA Astrophysics Data System (ADS)

Yu, Xinhong; Xing, Rubo; Luan, Shifang; Wang, Zhe; Han, Yanchun

2006-10-01

Micropatterning of functional polymer materials by micromolding in capillaries (MIMIC) with ice mold is reported in this paper. Ice mold was selected due to its thaw or sublimation. Thus, the mold can be easily removed. Furthermore, the polymer solution did not react with, swell, or adhere to the ice mold, so the method is suitable for many kinds of materials (such as P3HT, PMMA Alq 3/PVK, PEDOT: PSS, PS, P2VP, etc.). Freestanding polymer microstructures, binary polymer pattern, and microchannels have been fabricated by the use of ice mold freely.

Atomic-level imaging, processing and characterization of semiconductor surfaces

DOEpatents

Kazmerski, Lawrence L.

1995-01-01

A method for selecting and removing single specific atoms from a solid material surface uses photon biasing to break down bonds that hold the selected atom in the lattice and to reduce barrier effects that hold the atom from transferring to a probe. The photon bias is preferably light or other electromagnetic radiation with a wavelength and frequency that approximately matches the wave function of the target atom species to be removed to induce high energy, selective thermionic-like vibration. An electric field potential is then applied between the probe and the surface of the solid material to pull the atom out of the lattice and to transfer the atom to the probe. Different extrinsic atoms can be installed in the lattice sites that are vacated by the removed atoms by using a photon bias that resonates the extrinsic atom species, reversing polarity of the electric field, and blowing gas comprising the extrinsic atoms through a hollow catheter probe.

Atomic-level imaging, processing and characterization of semiconductor surfaces

DOEpatents

Kazmerski, L.L.

1995-08-22

A method for selecting and removing single specific atoms from a solid material surface uses photon biasing to break down bonds that hold the selected atom in the lattice and to reduce barrier effects that hold the atom from transferring to a probe. The photon bias is preferably light or other electromagnetic radiation with a wavelength and frequency that approximately matches the wave function of the target atom species to be removed to induce high energy, selective thermionic-like vibration. An electric field potential is then applied between the probe and the surface of the solid material to pull the atom out of the lattice and to transfer the atom to the probe. Different extrinsic atoms can be installed in the lattice sites that are vacated by the removed atoms by using a photon bias that resonates the extrinsic atom species, reversing polarity of the electric field, and blowing gas comprising the extrinsic atoms through a hollow catheter probe. 8 figs.

Cellulose membranes are more effective in holding back vital proteins and exhibit less interaction with plasma proteins during hemodialysis.

PubMed

Pešić, Ivana; Müller, Gerhard A; Baumann, Cosima; Dihazi, Gry H; Koziolek, Michael J; Eltoweissy, Marwa; Bramlage, Carsten; Asif, Abdul R; Dihazi, Hassan

2013-04-01

The vast majority of patients with end-stage renal disease are treated with intermittent hemodialysis as a form of renal replacement therapy. To investigate the impact of hemodialysis membrane material on vital protein removal, dialysates from 26 well-characterized hemodialysis patients were collected 5 min after beginning, during 5h of treatment, as well as 5 min before ending of the dialysis sessions. Dialysis sessions were performed using either modified cellulose (n=12) (low-flux and high flux) or synthetic Polyflux (n=14) (low-flux and high-flux) dialyzer. Protein removal during hemodialysis was quantified and the dialysate proteome patterns were analyzed by 2-DE, MS and Western blot. There was a clear correlation between the type of membrane material and the amount of protein removed. Synthetic Polyflux membranes exhibit strong interaction with plasma proteins resulting in a significantly higher protein loss compared to modified cellulosic membrane. Moreover, the proteomics analysis showed that the removed proteins represented different molecular weight range and different functional groups: transport proteins, protease inhibitors, proteins with role in immune response and regulations, constructive proteins and as a part of HLA immune complex. The effect of this protein removal on hemodialysis treatment outcome should be investigated in further studies. Copyright © 2013 Elsevier B.V. All rights reserved.

UiO-66 and its Br-modified derivates for elemental mercury removal.

PubMed

Zhang, Xiao; Shen, Boxiong; Zhu, Sheaowen; Xu, Huan; Tian, Linghui

2016-12-15

Phenyl bromine-appended metal-organic frameworks (Br-MOFs) were synthesized and applied in elemental mercury (Hg 0 ) removal from simulated flue gas, considering the stability of bromine on the materials at the same time. The techniques of PXRD, nitrogen adsorption, TGA and XPS were used to characterize the materials. Phenyl bromide on the MOFs was the main active site for Hg 0 capture. The optimal Br-MOF showed high Hg 0 removal efficiency of more than 99% for 48h at 200°C, whereas the efficiency of un-functionalized MOF and conventional bromine impregnated active carbon dropped to 59.8% and 91.2% within 5h, respectively. The crystalline integrity of the Br-MOF was maintained after Hg 0 adsorption. Br-MOF exhibited enhanced Hg 0 removal efficiency when SO 2 was introduced to the flue gas. However, exposure Br-MOF to flue gas with steam resulted in low Hg 0 removal efficiency. Bromine leaching experiments proved that Br-MOFs have high bromine stability over the Hg 0 adsorption process, avoiding the possible bromine pollution caused by the conventional bromine impregnated adsorbents. All of these results demonstrated the phenyl bromine-appended MOFs to be potential Hg 0 adsorbent regarding its high Hg 0 capture efficiency and low environmental risk. Copyright © 2016. Published by Elsevier B.V.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neeway, James J.; Asmussen, R. Matthew; Lawter, Amanda R.

Many efforts have focused on the sequestration and immobilization of 99Tc because the radionuclide is highly mobile in oxidizing environments and presents serious health risks due to its radiotoxicity and long half-life (t1/2 = 213 000 a). One of the more common methods for Tc removal from solution and immobilization in solids is based on reducing Tc from highly soluble Tc(VII) to sparingly soluble Tc(IV). In order to remove solution Tc through this reduction process, the Tc-sequestering solid must contain a reducing agent and, ideally, the Tc-sequestering material would function in a large range of chemical environments. For long-term stability,more » the reduced Tc would preferentially be incorporated into the resulting mineral structure instead of simply being sorbed onto the mineral surface. Here, we report results obtained from batch sorption experiments performed in anoxic and oxic conditions with two sulfide-containing potassium metal sulfide (KMS) materials, known as KMS-2 and KMS-2-SS. In deionized water in anoxic conditions after 15 d of contact, KMS-2 is capable of removing ~45% of Tc and KMS-2-SS is capable of removing ~90% of Tc. The improved performance of KMS-2-SS compared to KMS-2 in deionized water in anoxic conditions appears to be linked both to a higher pH resulting from the batch sorption experiments performed with KMS-2-SS and a higher overall purity of KMS-2-SS. Both materials perform even better in highly caustic (pH~13.5), high ionic strength (8.0 M) simulated Hanford low-activity waste solutions, removing more than 90% Tc after 15 d of contact in anoxic conditions. Post-reaction solids analysis indicate that Tc(VII) is reduced to Tc(IV) and that Tc(IV) is bonded to S atoms in the resulting KMS-2 structure in a Tc2S7 form. In contrast to previous ion exchange experiments with other KMS materials, the batch sorption experiments examining Tc removal cause the initially crystalline KMS materials to lose much of their initial long-range order.« less

Molecular Imprinted Polymer of Methacrylic Acid Functionalised β-Cyclodextrin for Selective Removal of 2,4-Dichlorophenol

PubMed Central

Surikumaran, Hemavathy; Mohamad, Sharifah; Sarih, Norazilawati Muhamad

2014-01-01

This work describes methacrylic acid functionalized β-cyclodextrin (MAA-βCD) as a novel functional monomer in the preparation of molecular imprinted polymer (MIP MAA-βCD) for the selective removal of 2,4-dichlorophenol (2,4-DCP). The polymer was characterized using Fourier Transform Infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) and Field Emission Scanning Electron Microscopy (FESEM) techniques. The influence of parameters such as solution pH, contact time, temperature and initial concentrations towards removal of 2,4-DCP using MIP MAA-βCD have been evaluated. The imprinted material shows fast kinetics and the optimum pH for removal of 2,4-DCP is pH 7. Compared with the corresponding non-imprinted polymer (NIP MAA-βCD), the MIP MAA-βCD exhibited higher adsorption capacity and outstanding selectivity towards 2,4-DCP. Freundlich isotherm best fitted the adsorption equilibrium data of MIP MAA-βCD and the kinetics followed a pseudo-second-order model. The calculated thermodynamic parameters showed that adsorption of 2,4-DCP was spontaneous and exothermic under the examined conditions. PMID:24727378

Plasma Radiofrequency Discharges as Cleaning Technique for the Removal of C-W Coatings

NASA Astrophysics Data System (ADS)

Cremona, A.; Vassallo, E.; Caniello, R.; Ghezzi, F.; Grosso, G.; Laguardia, L.

2013-06-01

Erosion of materials by chemical and physical sputtering is one of the most concern of plasma wall interaction in tokamaks. In divertor ITER-like tokamaks, where carbon and tungsten are planned to be used, hydrogenated C-W mixed compounds are expected to form by erosion, transport and re-deposition processes. The selection of these materials as divertor components involves lifetime and safety issues due to tritium retention in carbon co-deposits. In this paper a cleaning technique based on RF (13.56 MHz) capacitively coupled H2/Ar plasmas has been used to remove C-W mixed materials from test specimens. The dependence of the removal rate on the H2/Ar ratio and on the plasma pressure has been investigated by X-ray photoelectron spectroscopy, atomic force microscopy, profilometry as regards the solid phase and by Langmuir probe and optical emission spectroscopy as regards the plasma phase. The best result has been obtained with a H2/Ar ratio of 10/90 at a pressure of 1 Pa. An explanation based on a synergistic effect between physical sputtering due to energetic ions and chemical etching due to radicals, together with the pressure dependence of the ion energy distribution function, is given.

4-chlorophenol removal from water using graphite and graphene oxides as photocatalysts.

PubMed

Bustos-Ramírez, Karina; Barrera-Díaz, Carlos Eduardo; De Icaza-Herrera, Miguel; Martínez-Hernández, Ana Laura; Natividad-Rangel, Reyna; Velasco-Santos, Carlos

2015-01-01

Graphite and graphene oxides have been studied amply in the last decade, due to their diverse properties and possible applications. Recently, their functionality as photocatalytic materials in water splitting was reported. Research in these materials is increasing due to their band gap values around 1.8-4 eV, and therefore, these are comparable with other photocatalysts currently used in heterogeneous photocatalytic processes. Thus, this research reports the photocatalytic effectiveness of graphite oxide (GO) and graphene oxide (GEO) in the degradation of 4-chlorophenol (4-CP) in water. Under the conditions defined for this research, 92 and 97% of 4-CP were degraded with GO and GEO respectively, also 97% of total organic carbon was removed. In addition, by-products of 4-CP that produce a yellow solution obtained only using photolysis are eliminated by photocatalyst process with GO and GEO. The degradation of 4-CP was monitored by UV-Vis spectroscopy, High Performance Liquid Chromatography (HPLC) and Chemical Oxygen Demand (COD). Thus, photocatalytic activity to remove 4-CP from water employing GO and GEO without doping is successfully showed, and therefore, a new gate in research for these materials is opened.

Ion beam machining error control and correction for small scale optics.

PubMed

Xie, Xuhui; Zhou, Lin; Dai, Yifan; Li, Shengyi

2011-09-20

Ion beam figuring (IBF) technology for small scale optical components is discussed. Since the small removal function can be obtained in IBF, it makes computer-controlled optical surfacing technology possible to machine precision centimeter- or millimeter-scale optical components deterministically. Using a small ion beam to machine small optical components, there are some key problems, such as small ion beam positioning on the optical surface, material removal rate, ion beam scanning pitch control on the optical surface, and so on, that must be seriously considered. The main reasons for the problems are that it is more sensitive to the above problems than a big ion beam because of its small beam diameter and lower material ratio. In this paper, we discuss these problems and their influences in machining small optical components in detail. Based on the identification-compensation principle, an iterative machining compensation method is deduced for correcting the positioning error of an ion beam with the material removal rate estimated by a selected optimal scanning pitch. Experiments on ϕ10 mm Zerodur planar and spherical samples are made, and the final surface errors are both smaller than λ/100 measured by a Zygo GPI interferometer.

Comparison of the biological NH3 removal characteristics among four inorganic packing materials.

PubMed

Hirai, M; Kamamoto, M; Yani, M; Shoda, M

2001-01-01

Four inorganic packing materials were evaluated in terms of their availability as a packing material of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological NH3 removal characteristics and some physical properties. Porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calculated soil (D) were used. The superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of NH3 per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately = C > B > or = D. Packing materials A and C with high porosity, maximum water content, and suitable mean pore diameter showed excellent removal capacity.

New nanocomposite surfaces and thermal interface materials based on mesoscopic microspheres, polymers and graphene flakes

NASA Astrophysics Data System (ADS)

Dmitriev, Alex A.; Dmitriev, Alex S.; Makarov, Petr; Mikhailova, Inna

2018-04-01

In recent years, there has been a great interest in the development and creation of new functional energy mate-rials, including for improving the energy efficiency of power equipment and for effectively removing heat from energy devices, microelectronics and optoelectronics (power micro electronics, supercapacitors, cooling of processors, servers and data centers). In this paper, the technology of obtaining new nanocomposites based on mesoscopic microspheres, polymers and graphene flakes is considered. The methods of sequential production of functional materials from graphene flakes of different volumetric concentration using epoxy polymers, as well as the addition of monodisperse microspheres are described. Data are given on the measurement of the contact angle and thermal conductivity of these nanocomposites with respect to the creation of thermal interface materials for cooling devices of electronics, optoelectronics and power engineering.

The Remarkable Amphoteric Nature of Defective UiO‐66 in Catalytic Reactions

PubMed Central

Hajek, Julianna; Bueken, Bart; Waroquier, Michel; De Vos, Dirk

2017-01-01

Abstract One of the major requirements in solid acid and base catalyzed reactions is that the reactants, intermediates or activated complexes cooperate with several functions of catalyst support. In this work the remarkable bifunctional behavior of the defective UiO‐66(Zr) metal organic framework is shown for acid‐base pair catalysis. The active site relies on the presence of coordinatively unsaturated zirconium sites, which may be tuned by removing framework linkers and by removal of water from the inorganic bricks using a dehydration treatment. To elucidate the amphoteric nature of defective UiO‐66, the Oppenauer oxidation of primary alcohols has been theoretically investigated using density functional theory (DFT) and the periodic approach. The presence of acid and basic centers within molecular distances is shown to be crucial for determining the catalytic activity of the material. Hydrated and dehydrated bricks have a distinct influence on the acidity and basicity of the active sites. In any case both functions need to cooperate in a concerted way to enable the chemical transformation. Experimental results on UiO‐66 materials of different defectivity support the theoretical observations made in this work. PMID:28736581

Laser balancing system for high material removal rates

NASA Technical Reports Server (NTRS)

Jones, M. G.; Georgalas, G.; Ortiz, A. L.

1984-01-01

A laser technique to remove material in excess of 10 mg/sec from a spinning rotor is described. This material removal rate is 20 times greater than previously reported for a surface speed of 30 m/sec. Material removal enhancement was achieved by steering a focused laser beam with moving optics to increase the time of laser energy interaction with a particular location on the circumferential surface of a spinning rotor. A neodymium:yttrium aluminum garnet (Nd:YAG) pulse laser was used in this work to evaluate material removal for carbon steel, 347 stainless steel, Inconal 718, and titanium 6-4. This technique is applicable to dynamic laser balancing.

Soil Fungi and Macrofauna in the Neotropics

Treesearch

Yiqing Li; Grizelle Gonzalez

2008-01-01

Decomposition is a critical ecosystem function that decomposes dead organic materials, removes wastes, recycles nutrients and renews soils fertility. In natural ecosystems most nitrogen (N) and phosphorus (P) required for plant growth are supplied through the decomposition of detritus, relying therefore on the activities of soil microbes and microfauna. Decomposition...

DEVELOPMENT OF COST-EFFECTIVE NONCARBON SORBENTS FOR HG0 REMOVAL FROM COAL-FIRED POWER PLANTS

EPA Science Inventory

Noncarbon materials or mineral oxides (silica gel, alumina, molecular sieves, zeolites, and montmorillonite) were modified with various functional groups such as amine, amide, thiol, urea and active additives such as elemental mercury (Hg⁰) vapor at coal-fired utility ...

Programmatic Environmental Assessment (EA) for Hazardous Materials Removal at F. E. Warren Air Force Base, Wyoming

DTIC Science & Technology

2013-05-31

ACM). The FEW Environmental Planning Function ( EPF ) conducted the analysis of this proposed action. 2. PURPOSE AND NEED FOR ACTION. The... EPF determined that the proposed action has the potential to affect Air Quality, Occupational Safety and Health, Cultural Resources and Hazardous Waste

75 FR 75176 - Gastrointestinal Drugs Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-02

... cystic fibrosis, chronic pancreatitis, pancreatectomy (surgical removal of all or part of the pancreas), or other conditions that may impair or limit function of the pancreas. The pancreas is an organ... by the pancreas. FDA intends to make background material available to the public no later than 2...

Use of lignocellulose materials as sorption media for phosphorus removal

Treesearch

K.G. Karthikeyan; Mandla A. Tshabalala; Dongmei Wang

2002-01-01

The suitability of modified bark or wood fiber derived from southern yellow pine to function as P sorbents was investigated. Sorbent preparation process included grinding, size fractionation] extraction for surface activation] and treatment with polyallylamine hydrochloride (PAA HCI) or 3-chloro-2-hydroxypropyltrimethlyammonium chloride. SEM images revealed surface...

Assessment of some straw-derived materials for reducing the leaching potential of Metribuzin residues in the soil

NASA Astrophysics Data System (ADS)

Cara, Irina Gabriela; Trincă, Lucia Carmen; Trofin, Alina Elena; Cazacu, Ana; Ţopa, Denis; Peptu, Cătălina Anişoara; Jităreanu, Gerard

2015-12-01

Biomass (straw waste) can be used as raw to obtain materials for herbicide removal from wastewater. These by-products have some important advantages, being environmentally friendly, easily available, presenting low costs, and requiring little processing to increase their adsorptive capacity. In the present study, some materials derived from agricultural waste (wheat, corn and soybean straw) were investigated as potential adsorbents for metribuzin removal from aqueous solutions. The straw wastes were processed by grinding, mineralisation (850 °C) and KOH activation in order to improve their functional surface activity. The materials surface characteristics were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The adsorbents capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry for herbicide determination. For adsorption isotherms, the equilibrium time considered was 3 h. The experimental adsorption data were modelled by Freundlich and Langmuir models. The activated straw and ash-derived materials from wheat, corn and soybean increased the adsorption capacity of metribuzin with an asymmetrical behaviour. Overall, our results sustain that activated ash-derived from straw and activated straw materials can be a valuable solution for reducing the leaching potential of metribuzin through soil.

PRISM: Processing routines in IDL for spectroscopic measurements (installation manual and user's guide, version 1.0)

USGS Publications Warehouse

Kokaly, Raymond F.

2011-01-01

This report describes procedures for installing and using the U.S. Geological Survey Processing Routines in IDL for Spectroscopic Measurements (PRISM) software. PRISM provides a framework to conduct spectroscopic analysis of measurements made using laboratory, field, airborne, and space-based spectrometers. Using PRISM functions, the user can compare the spectra of materials of unknown composition with reference spectra of known materials. This spectroscopic analysis allows the composition of the material to be identified and characterized. Among its other functions, PRISM contains routines for the storage of spectra in database files, import/export of ENVI spectral libraries, importation of field spectra, correction of spectra to absolute reflectance, arithmetic operations on spectra, interactive continuum removal and comparison of spectral features, correction of imaging spectrometer data to ground-calibrated reflectance, and identification and mapping of materials using spectral feature-based analysis of reflectance data. This report provides step-by-step instructions for installing the PRISM software and running its functions.

Radioactive Barium Ion Trap Based on Metal-Organic Framework for Efficient and Irreversible Removal of Barium from Nuclear Wastewater.

PubMed

Peng, Yaguang; Huang, Hongliang; Liu, Dahuan; Zhong, Chongli

2016-04-06

Highly efficient and irreversible capture of radioactive barium from aqueous media remains a serious task for nuclear waste disposal and environmental protection. To address this task, here we propose a concept of barium ion trap based on metal-organic framework (MOF) with a strong barium-chelating group (sulfate and sulfonic acid group) in the pore structures of MOFs. The functionalized MOF-based ion traps can remove >90% of the barium within the first 5 min, and the removal efficiency reaches 99% after equilibrium. Remarkably, the sulfate-group-functionalized ion trap demonstrates a high barium uptake capacity of 131.1 mg g(-1), which surpasses most of the reported sorbents and can selectively capture barium from nuclear wastewater, whereas the sulfonic-acid-group-functionalized ion trap exhibits ultrafast kinetics with a kinetic rate constant k2 of 27.77 g mg(-1) min(-1), which is 1-3 orders of magnitude higher than existing sorbents. Both of the two MOF-based ion traps can capture barium irreversibly. Our work proposes a new strategy to design barium adsorbent materials and provides a new perspective for removing radioactive barium and other radionuclides from nuclear wastewater for environment remediation. Besides, the concrete mechanisms of barium-sorbent interactions are also demonstrated in this contribution.

Heavy metal removal mechanisms of sorptive filter materials for road runoff treatment and remobilization under de-icing salt applications.

PubMed

Huber, Maximilian; Hilbig, Harald; Badenberg, Sophia C; Fassnacht, Julius; Drewes, Jörg E; Helmreich, Brigitte

2016-10-01

The objective of this research study was to elucidate the removal and remobilization behaviors of five heavy metals (i.e., Cd, Cu, Ni, Pb, and Zn) that had been fixed onto sorptive filter materials used in decentralized stormwater treatment systems receiving traffic area runoff. Six filter materials (i.e., granular activated carbon, a mixture of granular activated alumina and porous concrete, granular activated lignite, half-burnt dolomite, and two granular ferric hydroxides) were evaluated in column experiments. First, a simultaneous preloading with the heavy metals was performed for each filter material. Subsequently, the remobilization effect was tested by three de-icing salt experiments in duplicate using pure NaCl, a mixture of NaCl and CaCl2, and a mixture of NaCl and MgCl2. Three layers of each column were separated to specify the attenuation of heavy metals as a function of depth. Cu and Pb were retained best by most of the selected filter materials, and Cu was often released the least of all metals by the three de-icing salts. The mixture of NaCl and CaCl2 resulted in a stronger effect upon remobilization than the other two de-icing salts. For the material with the highest retention, the effect of the preloading level upon remobilization was measured. The removal mechanisms of all filter materials were determined by advanced laboratory methods. For example, the different intrusions of heavy metals into the particles were determined. Findings of this study can result in improved filter materials used in decentralized stormwater treatment systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biochar-based functional materials in the purification of agricultural wastewater: Fabrication, application and future research needs.

PubMed

Wei, Dongning; Li, Bingyu; Huang, Hongli; Luo, Lin; Zhang, Jiachao; Yang, Yuan; Guo, Jiajun; Tang, Lin; Zeng, Guangming; Zhou, Yaoyu

2018-04-01

Nowadays, agricultural contamination is becoming more and more serious due to the rapid growth of agricultural industry, which discharged antibiotics, pesticides or toxic metals into farmlands. A large number of researchers have applied biochar-based functional materials to the treatment of agricultural wastewater contamination. Meanwhile, biochar has also proved to be a very promising and effective technology in water purification field due to its various beneficial properties (e.g., cost effective, high specific surface area, and surface reactive groups). The focus of this review is to highlight the fabrication methods and application of biochar-based functional materials with the removal of different agricultural contaminants, and discuss the underlying mechanisms. However, the application of biochar-based functional materials is currently under its infancy, with the main hindrance is identified as the gap between laboratory scale and field application, immaturity of engineered biochar production technologies, and lack of quality standards. In order to fill these knowledge gaps, more efforts should be made to pay for the relevant research in future studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Adsorption properties of regenerative materials for removal of low concentration of toluene.

PubMed

Xie, Zhen-Zhen; Wang, Lin; Cheng, Ge; Shi, Lei; Zhang, Yi-Bo

2016-12-01

A specific type of material, activated carbon fiber (ACF), was modified by SiO 2 , and the final products ACF-x were obtained as ACF-12.5, ACF-20, ACF-40, and ACF-80 according to different dosages of tetraethoxysilane (TEOS). The modified material on the ACF surface had a significant and smooth cover layer with low content of silica from scanning electron microscope (SEM) image. The modified ACF-x showed the stronger hydrophobicity, thermal stability, and adsorption capacity, which had almost no effect in the presence of water vapor and no destruction in multiple cycles. ACF-20 was proven as the most efficient adsorbent in humid conditions. The dual-function system composed of the regenerative adsorbents and the combustion catalyst would be efficient in consecutive toluene adsorption/oxidation cycles, in which the combustion catalyst was prepared by the displacement reaction of H 2 PtCl 6 with foam Ni. Therefore, the adsorption/catalytic oxidation could be a promising technique in the indoor air purification, especially in the case of very low volatile organic compound (VOC; toluene) concentration levels. Exploring highly effective adsorptive materials with less expensive costs becomes an urgent issue in the indoor air protection. ACF-20 modified by SiO 2 with Pt/Ni catalysts shows stronger hydrophobicity, thermal stability, and adsorption capacity. This dual-function system composed of the regenerative materials and the combustion catalyst would be a promising technique in the indoor air purification, especially in the case of removal of very low concentration of toluene.

Removal of phosphate from water by amine-functionalized copper ferrite chelated with La(III).

PubMed

Gu, Wei; Li, Xiaodi; Xing, Mingchao; Fang, Wenkan; Wu, Deyi

2018-04-01

Eutrophication has become a worldwide environmental problem and removing phosphorus from water/wastewater before discharge is essential. The purpose of our present study was to develop an efficient material in terms of both phosphate adsorption capacity and magnetic separability. To this end, we first compared the performances of four spinel ferrites, including magnesium, zinc, nickel and copper ferrites. Then we developed a copper ferrite-based novel magnetic adsorbent, by synthesizing 1,6-hexamethylenediamine-functionalized copper ferrite(CuFe 2 O 4 ) via a single solvothermal synthesis process followed by LaCl 3 treatment. The materials were characterized with X-ray diffraction, transmission electron microscope, vibrating sample magnetometer, Fourier transform infrared spectra and N 2 adsorption-desorption. The maximum adsorption capacity of our material, calculated from the Langmuir adsorption isotherm model, attained 32.59mg/g with a saturation magnetization of 31.32emu/g. Data of adsorption kinetics were fitted well to the psuedo-second-order model. Effects of solution pH and coexisting anions (Cl - , NO 3 - , SO 4 2- ) on phosphate adsorption were also investigated, showing that our material had good selectivity for phosphate. But OH - competed efficiently with phosphate for adsorption sites. Furthermore, increasing both NaOH concentration and temperature resulted in an enhancement of desorption efficiency. Thus NaOH solution could be used to desorb phosphate adsorbed on the material for reuse, by adopting a high NaOH concentration and/or a high temperature. Copyright © 2017 Elsevier B.V. All rights reserved.

Research on the magnetorheological finishing (MRF) technology with dual polishing heads

NASA Astrophysics Data System (ADS)

Huang, Wen; Zhang, Yunfei; He, Jianguo; Zheng, Yongcheng; Luo, Qing; Hou, Jing; Yuan, Zhigang

2014-08-01

Magnetorheological finishing (MRF) is a key polishing technique capable of rapidly converging to the required surface figure. Due to the deficiency of general one-polishing-head MRF technology, a dual polishing heads MRF technology was studied and a dual polishing heads MRF machine with 8 axes was developed. The machine has the ability to manufacture large aperture optics with high figure accuracy. The large polishing head is suitable for polishing large aperture optics, controlling large spatial length's wave structures, correcting low-medium frequency errors with high removal rates. While the small polishing head has more advantages in manufacturing small aperture optics, controlling small spatial wavelength's wave structures, correcting mid-high frequency and removing nanoscale materials. Material removal characteristic and figure correction ability for each of large and small polishing head was studied. Each of two polishing heads respectively acquired stable and valid polishing removal function and ultra-precision flat sample. After a single polishing iteration using small polishing head, the figure error in 45mm diameter of a 50 mm diameter plano optics was significantly improved from 0.21λ to 0.08λ by PV (RMS 0.053λ to 0.015λ). After three polishing iterations using large polishing head , the figure error in 410mm×410mm of a 430mm×430mm large plano optics was significantly improved from 0.40λ to 0.10λ by PV (RMS 0.068λ to 0.013λ) .This results show that the dual polishing heads MRF machine not only have good material removal stability, but also excellent figure correction capability.

Solid materials for removing metals and fabrication method

DOEpatents

Coronado, Paul R.; Reynolds, John G.; Coleman, Sabre J.

2004-10-19

Solid materials have been developed to remove contaminating metals and organic compounds from aqueous media. The contaminants are removed by passing the aqueous phase through the solid materials which can be in molded, granular, or powder form. The solid materials adsorb the metals and the organics leaving a purified aqueous stream. The materials are sol-gel and or sol-gel and granulated activated carbon (GAC) mixtures. The species-specific adsorption occurs through specific chemical modifications of the solids tailored towards the contaminant(s). The contaminated solid materials can then be disposed of or the contaminant can be removed and the solids recycled.

Multi-Functional, Micro Electromechanical Silicon Carbide Accelerometer

NASA Technical Reports Server (NTRS)

Okojie, Robert S. (Inventor)

2004-01-01

A method of bulk manufacturing SiC sensors is disclosed and claimed. Materials other than SiC may be used as the substrate material. Sensors requiring that the SiC substrate be pierced are also disclosed and claimed. A process flow reversal is employed whereby the metallization is applied first before the recesses are etched into or through the wafer. Aluminum is deposited on the entire planar surface of the metallization. Photoresist is spun onto the substantially planar surface of the Aluminum which is subsequently masked (and developed and removed). Unwanted Aluminum is etched with aqueous TMAH and subsequently the metallization is dry etched. Photoresist is spun onto the still substantially planar surface of Aluminum and oxide and then masked (and developed and removed) leaving the unimidized photoresist behind. Next, ITO is applied over the still substantially planar surface of Aluminum, oxide and unimidized photoresist. Unimidized and exposed photoresist and ITO directly above it are removed with Acetone. Next, deep reactive ion etching attacks exposed oxide not protected by ITO. Finally, hot phosphoric acid removes the Al and ITO enabling wires to connect with the metallization. The back side of the SiS wafer may be also etched.

Multi-functional micro electromechanical devices and method of bulk manufacturing same

NASA Technical Reports Server (NTRS)

Okojie, Robert S. (Inventor)

2004-01-01

A method of bulk manufacturing SiC sensors is disclosed and claimed. Materials other than SiC may be used as the substrate material. Sensors requiring that the SiC substrate be pierced are also disclosed and claimed. A process flow reversal is employed whereby the metallization is applied first before the recesses are etched into or through the wafer. Aluminum is deposited on the entire planar surface of the metallization. Photoresist is spun onto the substantially planar surface of the Aluminum which is subsequently masked (and developed and removed). Unwanted Aluminum is etched with aqueous TMAH and subsequently the metallization is dry etched. Photoresist is spun onto the still substantially planar surface of Aluminum and oxide and then masked (and developed and removed) leaving the unimidized photoresist behind. Next, ITO is applied over the still substantially planar surface of Aluminum, oxide and unimidized photoresist. Unimidized and exposed photoresist and ITO directly above it are removed with Acetone. Next, deep reactive ion etching attacks exposed oxide not protected by ITO. Finally, hot phosphoric acid removes the Al and ITO enabling wires to connect with the metallization. The back side of the SiC wafer may be also be etched.

46 CFR 147A.31 - Removal of fumigation material and warning signs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Removal of fumigation material and warning signs. 147A... material and warning signs. After ventilation is completed and a marine chemist or other qualified person... vessel, shall ensure that all warning signs are removed and fumigation containers and materials are...

46 CFR 147A.31 - Removal of fumigation material and warning signs.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Removal of fumigation material and warning signs. 147A... material and warning signs. After ventilation is completed and a marine chemist or other qualified person... vessel, shall ensure that all warning signs are removed and fumigation containers and materials are...

46 CFR 147A.31 - Removal of fumigation material and warning signs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Removal of fumigation material and warning signs. 147A... material and warning signs. After ventilation is completed and a marine chemist or other qualified person... vessel, shall ensure that all warning signs are removed and fumigation containers and materials are...

The Effect of Small Molecule Additives on the Self-Assembly and Functionality of Protein-Polymer Diblock Copolymers

NASA Astrophysics Data System (ADS)

Thomas, Carla; Xu, Liza; Olsen, Bradley

2013-03-01

Self-assembly of globular protein-polymer block copolymers into well-defined nanostructures provides a route towards the manufacture of protein-based materials which maintains protein fold and function. The model material mCherry-b-poly(N-isopropyl acrylamide) forms self-assembled nanostructures from aqueous solutions via solvent evaporation. To improve retention of protein functionality when dehydrated, small molecules such as trehalose and glycerol are added in solution prior to solvent removal. With as little as 10 wt% additive, improvements in retained functionality of 20-60% are observed in the solid-state as compared to samples in which no additive is present. Higher additive levels (up to 50%) continue to show improvement until approximately 100% of the protein function is retained. These large gains are hypothesized to originate from the ability of the additives to replace hydrogen bonds normally fulfilled by water. The addition of trehalose in the bulk material also improves the thermal stability of the protein by 15-20 °C, while glycerol decreases the thermal stability. Materials containing up to 50% additives remain microphase separated, and, upon incorporation of additives, nanostructure domain spacing tends to increase, accompanied by order-order transitions.

Characterization of dissolved organic matter in landfill leachate during the combined treatment process of air stripping, Fenton, SBR and coagulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, ZhiPing, E-mail: liulqs@163.com; Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020; Wu, WenHui

Highlights: • DOM fractions spectra analysis during the whole treatment process. • Efficient method was achieved to remove organic matters in landfill leachate. • Molecular weight distribution and fractions were discussed. - Abstract: A combined treatment process of air stripping + Fenton + sequencing batch reactor (SBR)+ coagulation was performed to remove the pollutants in landfill leachate. Molecular weight (MW) distribution and fractions of dissolved organic matter (DOM) were discussed to study the characteristics. The experiment showed that the removal rate of chemical oxygen demand (COD), five day biological oxygen demand (BOD{sub 5}) and ammonia nitrogen (NH{sub 3}−N) by themore » combined process were 92.8%, 87.8% and 98.0%, respectively. Humic acid (HA) and fulvic acid (FA) were the main fractions in raw leachate with 81.8% of the total COD concentration, while hydrophilic organic matter (HyI) was the dominant fraction in the final effluent of the combined process with 63.5% of the total COD concentration. After the combined treatment process, the removal rate of DOM and fractions HA, FA, HyI were 91.9%, 97.1%, 95.8% and 71.7%, respectively. Organic matters of MW < 2 k and MW > 100 k were removed with 90.5% and 97.9% COD concentration after the treatment. The ultraviolet–visible spectra (UV–vis), Fourier transform infrared spectra (FTIR) and three-dimensional excitation-emission matrices spectra (EEMs) indicated that benzene materials and phenol compounds were preferentially removed in air stripping. High MW matters, aromatic rings, conjugated moieties and some functional groups were mainly removed by Fenton. While small MW fractions, carboxylic acids, alcohols and protein-like materials were preferentially biodegraded via SBR. Fulvic-like and humic-like materials were mainly destroyed via Fenton oxidation and coagulation.« less

Method for chemically inactivating energetic materials and forming a nondetonable product therefrom

DOEpatents

Tadros, Maher E.

2002-01-01

A method for rendering nondetonble energetic materials, such as are contained in or removed from decommissioned ordnance. The energetic materials are either combined with epoxy hardener or are combined with other compounds, preferably amine compounds, to form a substance that functions as an epoxy hardener. According to the invention, energetic materials (including TNT, RDX and Composition B) that are treated according to the invention method yield a reaction product that is non-explosive, that serves to harden or cure conventional epoxy resin to form a stable, nonexplosive waste product. Epoxy hardener made using the method of the invention is also described.

Agricultural waste material as potential adsorbent for sequestering heavy metal ions from aqueous solutions - a review.

PubMed

Sud, Dhiraj; Mahajan, Garima; Kaur, M P

2008-09-01

Heavy metal remediation of aqueous streams is of special concern due to recalcitrant and persistency of heavy metals in environment. Conventional treatment technologies for the removal of these toxic heavy metals are not economical and further generate huge quantity of toxic chemical sludge. Biosorption is emerging as a potential alternative to the existing conventional technologies for the removal and/or recovery of metal ions from aqueous solutions. The major advantages of biosorption over conventional treatment methods include: low cost, high efficiency, minimization of chemical or biological sludge, regeneration of biosorbents and possibility of metal recovery. Cellulosic agricultural waste materials are an abundant source for significant metal biosorption. The functional groups present in agricultural waste biomass viz. acetamido, alcoholic, carbonyl, phenolic, amido, amino, sulphydryl groups etc. have affinity for heavy metal ions to form metal complexes or chelates. The mechanism of biosorption process includes chemisorption, complexation, adsorption on surface, diffusion through pores and ion exchange etc. The purpose of this review article is to provide the scattered available information on various aspects of utilization of the agricultural waste materials for heavy metal removal. Agricultural waste material being highly efficient, low cost and renewable source of biomass can be exploited for heavy metal remediation. Further these biosorbents can be modified for better efficiency and multiple reuses to enhance their applicability at industrial scale.

Surface tension models for a multi-material ALE code with AMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wangyi; Koniges, Alice; Gott, Kevin

A number of surface tension models have been implemented in a 3D multi-physics multi-material code, ALE–AMR, which combines Arbitrary Lagrangian Eulerian (ALE) hydrodynamics with Adaptive Mesh Refinement (AMR). ALE–AMR is unique in its ability to model hot radiating plasmas, cold fragmenting solids, and most recently, the deformation of molten material. The surface tension models implemented include a diffuse interface approach with special numerical techniques to remove parasitic flow and a height function approach in conjunction with a volume-fraction interface reconstruction package. These surface tension models are benchmarked with a variety of test problems. In conclusion, based on the results, themore » height function approach using volume fractions was chosen to simulate droplet dynamics associated with extreme ultraviolet (EUV) lithography.« less

Surface tension models for a multi-material ALE code with AMR

DOE PAGES

Liu, Wangyi; Koniges, Alice; Gott, Kevin; ...

2017-06-01

A number of surface tension models have been implemented in a 3D multi-physics multi-material code, ALE–AMR, which combines Arbitrary Lagrangian Eulerian (ALE) hydrodynamics with Adaptive Mesh Refinement (AMR). ALE–AMR is unique in its ability to model hot radiating plasmas, cold fragmenting solids, and most recently, the deformation of molten material. The surface tension models implemented include a diffuse interface approach with special numerical techniques to remove parasitic flow and a height function approach in conjunction with a volume-fraction interface reconstruction package. These surface tension models are benchmarked with a variety of test problems. In conclusion, based on the results, themore » height function approach using volume fractions was chosen to simulate droplet dynamics associated with extreme ultraviolet (EUV) lithography.« less

Filter materials for metal removal from mine drainage--a review.

PubMed

Westholm, Lena Johansson; Repo, Eveliina; Sillanpää, Mika

2014-01-01

A large number of filter materials, organic and inorganic, for removal of heavy metals in mine drainage have been reviewed. Bark, chitin, chitosan, commercial ion exchangers, dairy manure compost, lignite, peat, rice husks, vegetal compost, and yeast are examples of organic materials, while bio-carbons, calcareous shale, dolomite, fly ash, limestone, olivine, steel slag materials and zeolites are examples of inorganic materials. The majority of these filter materials have been investigated in laboratory studies, based on various experimental set-ups (batch and/or column tests) and different conditions. A few materials, for instance steel slag materials, have also been subjects to field investigations under real-life conditions. The results from these investigations show that steel slag materials have the potential to remove heavy metals under different conditions. Ion exchange has been suggested as the major metal removal mechanisms not only for steel slag but also for lignite. Other suggested removal mechanisms have also been identified. Adsorption has been suggested important for activated carbon, precipitation for chitosan and sulphate reduction for olivine. General findings indicate that the results with regard to metal removal vary due to experimental set ups, composition of mine drainage and properties of filter materials and the discrepancies between studies renders normalisation of data difficult. However, the literature reveals that Fe, Zn, Pb, Hg and Al are removed to a large extent. Further investigations, especially under real-life conditions, are however necessary in order to find suitable filter materials for treatment of mine drainage.

Removal of radioactive and other hazardous material from fluid waste

DOEpatents

Tranter, Troy J [Idaho Falls, ID; Knecht, Dieter A [Idaho Falls, ID; Todd, Terry A [Aberdeen, ID; Burchfield, Larry A [W. Richland, WA; Anshits, Alexander G [Krasnoyarsk, RU; Vereshchagina, Tatiana [Krasnoyarsk, RU; Tretyakov, Alexander A [Zheleznogorsk, RU; Aloy, Albert S [St. Petersburg, RU; Sapozhnikova, Natalia V [St. Petersburg, RU

2006-10-03

Hollow glass microspheres obtained from fly ash (cenospheres) are impregnated with extractants/ion-exchangers and used to remove hazardous material from fluid waste. In a preferred embodiment the microsphere material is loaded with ammonium molybdophosphonate (AMP) and used to remove radioactive ions, such as cesium-137, from acidic liquid wastes. In another preferred embodiment, the microsphere material is loaded with octyl(phenyl)-N-N-diisobutyl-carbamoylmethylphosphine oxide (CMPO) and used to remove americium and plutonium from acidic liquid wastes.

Bioconjugated graphene oxide hydrogel as an effective adsorbent for cationic dyes removal.

PubMed

Soleimani, Khadijeh; Tehrani, Abbas Dadkhah; Adeli, Mohsen

2018-01-01

In this study, graphene oxide - cellulose nanowhiskers nanocomposite hydrogel was easily synthesized through covalent functionalization of cellulose nanowhiskers with graphene oxide via a facile approach. The nitrene chemistry applied for covalent functionalization of graphene oxide sheets. The surface morphology and chemical structure of the nanocomposite hydrogel were characterized by FTIR, TGA, Raman, XRD, elemental analysis and SEM. The UV/Visible absorption spectrum revealed that the obtained porous nanocomposite hydrogel can efficiently remove cationic dyes such as methylene blue (MB) and Rhodamine B (RhB) from wastewater with high absorption power. The adsorption process showed that 100% of MB and 90% of RhB have been removed and the equilibrium state has been reached in 15min for low concentration solutions in accordance with the pseudo-second-order model. Moreover, the sample exhibited stable performance after being used several times. High adsorption capacity and easy recovery are the efficient factors making these materials as good adsorbent for water pollutants and wastewater treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Ion beam figuring of highly steep mirrors with a 5-axis hybrid machine tool

NASA Astrophysics Data System (ADS)

Yin, Xiaolin; Tang, Wa; Hu, Haixiang; Zeng, Xuefeng; Wang, Dekang; Xue, Donglin; Zhang, Feng; Deng, Weijie; Zhang, Xuejun

2018-02-01

Ion beam figuring (IBF) is an advanced and deterministic method for optical mirror surface processing. The removal function of IBF varies with the different incident angles of ion beam. Therefore, for the curved surface especially the highly steep one, the Ion Beam Source (IBS) should be equipped with 5-axis machining capability to remove the material along the normal direction of the mirror surface, so as to ensure the stability of the removal function. Based on the 3-RPS parallel mechanism and two dimensional displacement platform, a new type of 5-axis hybrid machine tool for IBF is presented. With the hybrid machine tool, the figuring process of a highly steep fused silica spherical mirror is introduced. The R/# of the mirror is 0.96 and the aperture is 104mm. The figuring result shows that, PV value of the mirror surface error is converged from 121.1nm to32.3nm, and RMS value 23.6nm to 3.4nm.

Effect of Fe(II)/Ce(III) dosage ratio on the structure and anion adsorptive removal of hydrothermally precipitated composites: Insights from EXAFS/XANES, XRD and FTIR.

PubMed

Chubar, Natalia; Gerda, Vasyl; Banerjee, Dipanjan; Yablokova, Ganna

2017-02-01

In this work, we present material chemistry in the hydrothermal synthesis of new complex structure materials based on various dosage ratios of Fe and Ce (1:0, 2:1, 1:1, 1:2, 0:1), characterize them by the relevant methods that allow characterization of both crystalline and amorphous phases and correlate their structure/surface properties with the adsorptive performance of the five toxic anions. The applied synthesis conditions resulted in the formation of different compounds of Fe and Ce components. The Fe-component was dominated by various phases of Fe hydrous oxides, whereas the Ce-component was composed of various phases of Ce carbonates. The presence of two metal salts in raw materials resulted in the formation of a mesoporous structure and averaged the surface area compared to one metal-based material. The surface of all Fe-Ce composites was abundant in Fe component phases. Two-metal systems showed stronger anion removal performance than one-metal materials. The best adsorption was demonstrated by Fe-Ce based materials that had low crystallinity, that were rich in phases and that exhibited surfaces were abundant in greater number of surface functional groups. Notably, Fe extended fine structures simulated by EXAFS in these better adsorbents were rich from oscillations from both heavy and light atoms. This work provides new insights on the structure of composite inorganic materials useful to develop their applications in adsorption and catalysis. It also presents new inorganic anion exchangers with very high removal potential to fluoride and arsenate. Copyright © 2016 Elsevier Inc. All rights reserved.

Halide removal from aqueous solution by novel silver-polymeric materials.

PubMed

A M S, Polo; I, Velo-Gala; M, Sánchez-Polo; U, von Gunten; J J, López-Peñalver; J, Rivera-Utrilla

2016-12-15

The objective of this study was to analyze the behavior of a new material, silver-doped polymeric cloth (Ag-cloth), in the removal of bromide and iodide from waters. Silver is immobilized on the cloth, guaranteeing selective adsorption of the halide ions as retained silver halides that therefore do not pass into the solution. Results indicate that Ag 0 reacts with H 2 O 2 in the first phases of the process, yielding Ag + and superoxide radical; however, as the process advances, this radical favors Ag + reduction. Increases in the concentration of H 2 O 2 augment the capacity of the Ag-cloth to remove halides from the medium up to a maximum concentration (55μM), above which the removal capacity remains constant (Xm≅1.3-1.8mg halide/g Ag-cloth). Thus, when there is excess H 2 O 2 in the medium, secondary competitive reactions that take place in the process guarantee a constant Ag + concentration, which defines the maximum adsorption capacity of Ag-cloth, reducing its ability to remove halides. Ag-cloth has a higher capacity to remove iodide than bromide, and the presence of organic matter or chloride reduces its capacity to remove iodide or bromide from water. The results obtained shown that the capacity of Ag 0 with H 2 O 2 significantly varies as a function of the medium pH from 1mg Br - /g Ag-cloth at very low pH to 1.6mg/g Ag-cloth at pH9. Copyright © 2016 Elsevier B.V. All rights reserved.

Small-diameter trees used for chemithermomechanical pulps.

Treesearch

Gary C. Myers; R. James Barbour; Said M. Abubakr

1999-01-01

During the course of restoring and maintaining forest ecosystem health and function in the western interior of the United States, many small-diameter stems are removed from densely stocked stands. In general, these materials are considered nonusable or underutilized. Information on the properties of these resources is needed to help managers understand when timber...

Forest biodiversity and woody biomass harvesting

Treesearch

Deahn M. Donner; T. Bently Wigley; Darren A. Miller

2017-01-01

With the expected increase in demand for woody biomass to help meet renewable energy needs, one principal sustainability question has been whether this material can be removed from forest stands while still conserving biological diversity and retaining ecosystem functioning (Hecht et al. 2009; Berch, Morris, and Malcolm 2011; Ridley et al. 2013). In general,...

Fabrication of the novel hydrogel based on waste corn stalk for removal of methylene blue dye from aqueous solution

NASA Astrophysics Data System (ADS)

Ma, Dongzhuo; Zhu, Baodong; Cao, Bo; Wang, Jian; Zhang, Jianwei

2017-11-01

The novel hydrogel based on waste corn stalk was synthetized by aqueous solution polymerization technique with functional monomers in the presence of organic montmorillonite (OMMT) under ultrasonic. In this study, batch adsorption experiments were carried out to research the effect of initial dye concentration, the dosage of hydrogel, stirring speed, contact time and temperature on the adsorption of methylene blue (MB) dye. The adsorption process was best described by the pseudo-second-order kinetic model, which confirmed that it should be a chemical process. Furthermore, we ascertained the rate controlling step by establishing the intraparticle diffusion model and the liquid film diffusion model. The adsorption and synthesis mechanisms were vividly depicted in our work as well. Structural and morphological characterizations by virtue of FTIR, FESEM, and Biomicroscope supported the relationship between the adsorption performance and material's microstructure. This research is a valuable contribution for the environmental protection, which not only converts waste corn stalks into functional materials, but improves the removal of organic dye from sewage water.

Asbestos Utilization Costs on the Example of Functioning Landfill of Hazardous Waste

NASA Astrophysics Data System (ADS)

Polek, Daria

2017-12-01

Asbestos is a trademark of mineral fibres, which are the natural minerals found in nature. Products containing asbestos fibres, in accordance with the national and EU legislation, are covered by the production prohibition and forced to be removed. In Poland, the asbestos removal process started with the adaptation of the EU law by the Council of Ministers Treatment Program of the National Asbestos for the years 2009-2032. The purpose of the dissertation was to analyse the costs associated with the disposal of the costs of collection, transport and disposal of waste. Methodology consisted in obtaining information on the raw materials needed to produce asbestos sheets. The analysis allowed us to determine the asbestos removal cost and include state subsidies in the calculations.

Food-processes wastewaters treatment using food solid-waste materials as adsorbents or absorbents

NASA Astrophysics Data System (ADS)

Rapti, Ilaira; Georgopoulos, Stavros; Antonopoulou, Maria; Konstantinou, Ioannis; Papadaki, Maria

2016-04-01

The wastewaters generated by olive-mills during the production of olive oil, wastewaters from a dairy and a cow-farm unit and wastewaters from a small food factory have been treated by means of selected materials, either by-products of the same units, or other solid waste, as absorbents or adsorbents in order to identify the capacity of those materials to remove organic load and toxicity from the aforementioned wastewaters. The potential of both the materials used as absorbents as well as the treated wastewaters to be further used either as fertilizers or for agricultural irrigation purposes are examined. Dry olive leaves, sheep wool, rice husks, etc. were used either in a fixed-bed or in a stirred batch arrangemen,t employing different initial concentrations of the aforementioned wastewaters. The efficiency of removal was assessed using scpectrophotometric methods and allium test phytotoxicity measurements. In this presentation the response of each material employed is shown as a function of absorbent/adsorbent quantity and kind, treatment time and wastewater kind and initial organic load. Preliminary results on the potential uses of the adsorbents/absorbents and the treated wastewaters are also shown. Keywords: Olive-mill wastewaters, dairy farm wastewaters, olive leaves, zeolite, sheep wool

Long-term results of the use of silicone sheets after diskectomy in the temporomandibular joint: clinical, radiographic and histopathologic findings.

PubMed

Schliephake, H; Schmelzeisen, R; Maschek, H; Haese, M

1999-10-01

The aim of the present study was to evaluate the long-term results of a group of patients who had the disk of the temporomandibular joint (TMJ) removed and permanently replaced by a silicone sheet. The study group comprised 48 patients, treated in the period from 1983 to 1993. In eight patients, the implants had to be removed after an average interval of 5.6 years and they were submitted for histopathological examination. Twenty-five of the 40 patients with silastic implants in place, and five of the 8 patients who had their implants removed, were available for long-term follow-up (mean interval of 7.0 years, SD 2.8 years). Clinical function was rated according to the Helkimo Dysfunction Index and compared to the preoperative findings. Results showed decreased tenderness of muscles and joints to palpation and increased mouth opening, but no statistically significant improvement in joint function. In 4 patients, a decrease in condylar width was found, while another 4 patients presented with thickening of the condyle by appositional bone formation. Histopathology of the failed implants showed scattered fragments of silastic material and dacron fibers with accumulation of histiocytes in immediate contact with the silicone particles and phagocytozed intracellular material. T-lymphocytes were also present in the vicinity of the silicone particles.

Optimized method for manufacturing large aspheric surfaces

NASA Astrophysics Data System (ADS)

Zhou, Xusheng; Li, Shengyi; Dai, Yifan; Xie, Xuhui

2007-12-01

Aspheric optics are being used more and more widely in modern optical systems, due to their ability of correcting aberrations, enhancing image quality, enlarging the field of view and extending the range of effect, while reducing the weight and volume of the system. With optical technology development, we have more pressing requirement to large-aperture and high-precision aspheric surfaces. The original computer controlled optical surfacing (CCOS) technique cannot meet the challenge of precision and machining efficiency. This problem has been thought highly of by researchers. Aiming at the problem of original polishing process, an optimized method for manufacturing large aspheric surfaces is put forward. Subsurface damage (SSD), full aperture errors and full band of frequency errors are all in control of this method. Lesser SSD depth can be gained by using little hardness tool and small abrasive grains in grinding process. For full aperture errors control, edge effects can be controlled by using smaller tools and amendment model with material removal function. For full band of frequency errors control, low frequency errors can be corrected with the optimized material removal function, while medium-high frequency errors by using uniform removing principle. With this optimized method, the accuracy of a K9 glass paraboloid mirror can reach rms 0.055 waves (where a wave is 0.6328μm) in a short time. The results show that the optimized method can guide large aspheric surface manufacturing effectively.

27 CFR 24.290 - Removal of wine as distilling material.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Removal of wine as... TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Removal, Return and Receipt of Wine Removals Without Payment of Tax § 24.290 Removal of wine as distilling material. (a) General. Still wine may be...

Removal of Organic Pollutants from Water Using Superwetting Materials.

PubMed

Li, Lingxiao; Zhang, Junping; Wang, Aiqin

2018-02-01

The frequent occurrence of water pollution accidents and the leakage of organic pollutants have caused severe environmental and ecological crisis. It is thus highly imperative to find efficient materials to solve the problem. Inspired by the lotus leaf, superwetting materials are receiving increasing attention in the field of removal of organic pollutants from water. Various superwetting materials have been successfully generated and integrated into devices for removal of organic pollutants from water. On the basis of our previous work in the field, we summarized in this account the progress of removal of (1) floating and underwater insoluble, (2) emulsified insoluble, and (3) both insoluble and soluble organic pollutants from water using superwetting materials including superhydrophobic & superoleophilic materials, superhydrophilic & underwater superoleophobic materials, and materials with controllable wettability. The superwetting materials are in the forms of 2D porous materials, 3D porous materials and particles, etc. Finally, the current state and future challenges in this field are discussed. We hope this account could shed light on the design of novel superwetting materials for efficient removal of organic pollutants from water. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Progress in the preparation and application of modified biochar for improved contaminant removal from water and wastewater.

PubMed

Ahmed, Mohammad Boshir; Zhou, John L; Ngo, Huu H; Guo, Wenshan; Chen, Mengfang

2016-08-01

Modified biochar (BC) is reviewed in its preparation, functionality, applications and regeneration. The nature of precursor materials, preparatory conditions and modification methods are key factors influencing BC properties. Steam activation is unsuitable for improving BC surface functionality compared with chemical modifications. Alkali-treated BC possesses the highest surface functionality. Both alkali modified BC and nanomaterial impregnated BC composites are highly favorable for enhancing the adsorption of different contaminants from wastewater. Acidic treatment provides more oxygenated functional groups on BC surfaces. The Langmuir isotherm model provides the best fit for sorption equilibria of heavy metals and anionic contaminants, while the Freundlich isotherm model is the best fit for emerging contaminants. The pseudo 2(nd) order is the most appropriate model of sorption kinetics for all contaminants. Future research should focus on industry-scale applications and hybrid systems for contaminant removal due to scarcity of data. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation and mechanism of ammonia nitrogen removal using sediments from a malodorous river

NASA Astrophysics Data System (ADS)

Chen, Xing; Jiang, Xia; Huang, Wei

2018-03-01

Malodorous rivers are among the major environmental problems of cities in developing countries. In addition to the unpleasant smell, the sediments of such rivers can act as a sink for pollutants. The excessive amount of ammonia nitrogen (NH3-N) in rivers is the main factor that causes the malodour. Therefore, a suitable method is necessary for sediment disposition and NH3-N removal in malodorous rivers. The sediment in a malodorous river (PS) in Beijing, China was selected and modified via calcination (PS-D), Na+ doping (PS-Na) and calcination-Na+ doping (PS-DNa). The NH3-N removal efficiency using the four sediment materials was evaluated, and results indicated that the NH3-N removal efficiency using the modified sediment materials could reach over 60%. PS-DNa achieved the highest NH3-N removal efficiency (90.04%). The kinetics study showed that the pseudo-second-order model could effectively describe the sorption kinetics and that the exterior activated site had the main function of P sorption. The results of the sorption isotherms indicated that the maximum sorption capacities of PS-Na, PS-D and PS-DNa were 0.343, 0.831 and 1.113 mg g-1, respectively, and a high temperature was favourable to sorption. The calculated thermodynamic parameters suggested that sorption was a feasible or spontaneous (ΔG < 0), entropy-driven (ΔS > 0), and endothermic (ΔH > 0) reaction.

Metal-free catalysis of persulfate activation and organic-pollutant degradation by nitrogen-doped graphene and aminated graphene.

PubMed

Chen, Hao; Carroll, Kenneth C

2016-08-01

We evaluated three types of functionalized, graphene-based materials for activating persulfate (PS) and removing (i.e., sorption and oxidation) sulfamethoxazole (SMX) as a model emerging contaminant. Although advanced oxidative water treatment requires PS activation, activation requires energy or chemical inputs, and toxic substances are contained in many catalysts. Graphene-based materials were examined herein as an alternative to metal-based catalysts. Results show that nitrogen-doped graphene (N-GP) and aminated graphene (NH2-GP) can effectively activate PS. Overall, PS activation by graphene oxide was not observed in this study. N-GP (50 mg L(-1)) can rapidly activate PS (1 mM) to remove >99.9% SMX within 3 h, and NH2-GP (50 mg L(-1)) activated PS (1 mM) can also remove 50% SMX within 10 h. SMX sorption and total removal was greater for N-GP, which suggests oxidation was enhanced by increasing proximity to PS activation sites. Increasing pH enhanced the N-GP catalytic ability, and >99.9% SMX removal time decreased from 3 h to 1 h when pH increased from 3 to 9. However, the PS catalytic ability was inhibited at pH 9 for NH2-GP. Increases in ionic strength (100 mM NaCl or Na2SO4) and addition of radical scavengers (500 mM ethanol) both had negligible impacts on SMX removal. With bicarbonate addition (100 mM), while the catalytic ability of N-GP remained unaltered, NH2-GP catalytic ability was inhibited completely. Humic acid (250 mg L(-1)) was partially effective in inhibiting SMX removal in both N-GP and NH2-GP systems. These results have implications for elucidating oxidant catalysis mechanisms, and they quantify the ability of functionalization of graphene with hetero-atom doping to effectively catalyze PS for water treatment of organic pollutants including emerging contaminants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simplified Prosthetic Rehabilitation of a Patient after Oral Cancer Removal.

PubMed

Kranjčić, Josip; Džakula, Nikola; Vojvodić, Denis

2016-09-01

The treatment of patients with oral cancer is complex: a multidisciplinary approach needs to be taken and maxillofacial and oral surgeons, an oncologist, a prosthodontist should be included, and a psychologist is often needed. This case report describes the prosthetic rehabilitation of a patient after surgical removal of oral cancer with obturator prosthesis. Resection cavity was located in central part of the hard palate and the condition belonged to Aramany class 3 maxillary defects. The two-step impression technique of denture bearing area was used and the resection of cavity was performed. A primary impression-the impression of denture bearing area was made using irreversible hydrocolloid material, while the second impression - the impression of resection cavity was made using condensation silicone material and obturator prosthesis framework. The obturator prosthesis replaced lost teeth, improved oral function and esthetics at minimal costs.

Sonochemical synthesis of magnetic responsive Fe3O4@TMU-17-NH2 composite as sorbent for highly efficient ultrasonic-assisted denitrogenation of fossil fuel.

PubMed

Mirzaie, Abbas; Musabeygi, Tahereh; Afzalinia, Ahmad

2017-09-01

In this work, a novel magnetic responsive composite was fabricated by encapsulation of Fe 3 O 4 nanoparticles into an amino-functionalized MOF (TMU-17-NH 2 ) under ultrasound irradiation. The prepared materials were characterized by several techniques such as elemental analyses, PXRD, FT-IR, N 2 adsorption, TGA and ICP. This composite has been applied to the adsorptive removal of nitrogen-contain compounds in model liquid fuel. The prepared composite demonstrates very good performance for the removal of NCCs. The maximum adsorption capacity of IND and QUI over prepared composite calculated 375.93 and 310.18mg·g -1 at 25°C, respectively. The composite material is magnetically separable and reusable for several times. Copyright © 2016 Elsevier B.V. All rights reserved.

Nanoscale Materials for Human Space Exploration: Regenerable CO2 Removal

NASA Technical Reports Server (NTRS)

Arepalli, Sivaram; Nikolaev, Pasha; Gorelik, Olga; Huffman, Chad; Moloney, Padraig; Allada, Ram; Yowell, Leonard

2005-01-01

This viewgraph presentation reviews the use of Nanoscale materials in CO2 removal. It presented the background and review work on regenerable CO2 removal for spaceflight application. It demonstrated a new strategy for developing solid-supported amine absorbents based on carbon nanotube materials.

Study of CO2 sorbents for extravehicular activity

NASA Technical Reports Server (NTRS)

Colombo, G. V.

1973-01-01

Portable life support equipment was studied for meeting the requirements of extravehicular activities. Previous studies indicate that the most promising method for performing the CO2 removal function removal function were metallic oxides and/or metallic hydroxides. Mgo, Ag2, and Zno metallic oxides and Mg(OH)2 and Zn(OH)2 metallic hydroxides were studied, by measuring sorption and regeneration properties of each material. The hydroxides of Mg and Zn were not regenerable and the zinc oxide compounds showed no stable form. A silver oxide formulation was developed which rapidly absorbs approximately 95% of its 0.19 Kg CO2 Kg oxide and has shown no sorption or structural degeneration through 22 regenerations. It is recommended that the basic formula be further developed and tested in large-scale beds under simulated conditions.

The synthesis of novel hybrid thiol-functionalized nano-structured SBA-15

NASA Astrophysics Data System (ADS)

Hoang, Van Duc; Phuong Dang, Tuyet; Khieu Dinh, Quang; Phu Nguyen, Huu; Vu, Anh Tuan

2010-09-01

Mesoporous thiol-functionalized SBA-15 has been directly synthesized by co-condensation of tetraethyl orthosilicate (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) with triblock copolymer P123 as-structure-directing agent under hydrothermal conditions. Surfactant removal was performed by Soxhlet ethanol extraction. These materials have been characterized by powder x-ray diffraction (XRD), nitrogen adsorption/desorption (BET model), transmission electron microscopy (TEM), thermal analysis, infrared spectroscopy (IR) and energy-dispersive x-ray spectroscopy (EDX). The main parameters, such as the initial molar ratio of MPTMS to TEOS, the time of adding MPTMS to synthesized gel and the Soxhlet ethanol extraction on the thiol functionalized SBA-15 with high thiol content and highly ordered hexagonal mesostructure, were investigated and evaluated. The adsorption capacity of the thiol-functionalized and non-functionalized SBA-15 materials for Pb2+ ion from aqueous solution was tested. It was found that the Pb2+ adsorption capacity of the thiol functionalized SBA-15 is three times higher than that of non-functionalized SBA-15.

Water decontamination by polyoxometalate-functionalized 3D-printed hierarchical porous devices.

PubMed

Ji, Yuanchun; Ma, Yuan; Ma, Yanjiao; Asenbauer, Jakob; Passerini, Stefano; Streb, Carsten

2018-03-25

The design of organic-inorganic hybrid composites has revolutionized application-driven materials design. Here, we show how hierarchically structured, 3D-printed ABS polymers can be surface-functionalized with lacunary polyoxometalate anions ([α-PW 9 O 34 ] 9- ) featuring heavy-metal binding sites. The resulting composite is highly porous and can be used for the removal of transition-metal pollutants from water. Thus, a facile blueprint for decentralized production of water filtration devices is reported.

Self-cleaning of superhydrophobic surfaces by spontaneously jumping condensate drops

NASA Astrophysics Data System (ADS)

Wisdom, Katrina; Watson, Jolanta; Watson, Gregory; Chen, Chuan-Hua

2012-11-01

The self-cleaning function of superhydrophobic surfaces is conventionally attributed to the removal of contaminating particles by impacting or rolling water droplets, which implies the action of external forces such as gravity. Here, we demonstrate a new self-cleaning mechanism, whereby condensate drops spontaneously jump upon coalescence on a superhydrophobic surface, and the merged drop self-propels away from the surface along with the contaminants. The jumping-condensate mechanism is shown to autonomously clean superhydrophobic cicada wings, where the contaminating particles cannot be removed by external wind flow. Our findings offer new insights for the development of self-cleaning materials.

40 CFR 262.208 - Removing containers of unwanted material from the laboratory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Laboratories Owned by Eligible Academic Entities § 262.208 Removing containers of unwanted material from the laboratory. (a) Removing containers of unwanted material on a regular schedule. An eligible academic entity... months of each container's accumulation start date. (b) The eligible academic entity must specify in Part...

40 CFR 262.208 - Removing containers of unwanted material from the laboratory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Laboratories Owned by Eligible Academic Entities § 262.208 Removing containers of unwanted material from the laboratory. (a) Removing containers of unwanted material on a regular schedule. An eligible academic entity... months of each container's accumulation start date. (b) The eligible academic entity must specify in Part...

40 CFR 262.208 - Removing containers of unwanted material from the laboratory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Laboratories Owned by Eligible Academic Entities § 262.208 Removing containers of unwanted material from the laboratory. (a) Removing containers of unwanted material on a regular schedule. An eligible academic entity... months of each container's accumulation start date. (b) The eligible academic entity must specify in Part...

The effective magnetoelectric coefficients of polycrystalline Cr2O3 annealed in perpendicular electric and magnetic fields

NASA Astrophysics Data System (ADS)

Liu, Y. Y.; Xie, S. H.; Jin, G.; Li, J. Y.

2009-04-01

Magnetoelectric annealing is necessary to remove antiferromagnetic domains and induce macroscopic magnetoelectric effect in polycrystalline magnetoelectric materials, and in this paper, we study the effective magnetoelectric properties of perpendicularly annealed polycrystalline Cr2O3 using effective medium approximation. The effect of temperatures, grain aspect ratios, and two different types of orientation distribution function have been analyzed, and unusual material symmetry is observed when the orientation distribution function only depends on Euler angle ψ. Optimal grain aspect ratio and texture coefficient are also identified. The approach can be applied to analyze the microstructural field distribution and macroscopic properties of a wide range of magnetoelectric polycrystals.

Abrasive rolling effects on material removal and surface finish in chemical mechanical polishing analyzed by molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Si, Lina; Guo, Dan; Luo, Jianbin; Lu, Xinchun; Xie, Guoxin

2011-04-01

In an abrasive chemical mechanical polishing (CMP) process, materials were considered to be removed by abrasive sliding and rolling. Abrasive sliding has been investigated by many molecular dynamics (MD) studies; while abrasive rolling was usually considered to be negligible and therefore was rarely investigated. In this paper, an MD simulation was used to study the effects of abrasive rolling on material removal and surface finish in the CMP process. As the silica particle rolled across the silicon substrate, some atoms of the substrate were dragged out from their original positions and adhered to the silica particle, leaving some atomic vacancies on the substrate surface. Meanwhile, a high quality surface could be obtained. During the abrasive rolling process, the influencing factors of material removal, e.g., external down force and driving force, were also discussed. Finally, MD simulations were carried out to examine the effects of abrasive sliding on material removal under the same external down force as abrasive rolling. The results showed that the ability of abrasive rolling to remove material on the atomic scale was not notably inferior to that of abrasive sliding. Therefore, it can be proposed that both abrasive sliding and rolling play important roles in material removal in the abrasive CMP of the silicon substrate.

3D Aerogel of Graphitic Carbon Nitride Modified with Perylene Imide and Graphene Oxide for Highly Efficient Nitric Oxide Removal under Visible Light.

PubMed

Hu, Jundie; Chen, Dongyun; Li, Najun; Xu, Qingfeng; Li, Hua; He, Jinghui; Lu, Jianmei

2018-05-01

3D materials are considered promising for photocatalytic applications in air purification because of their large surface areas, controllability, and recyclability. Here, a series of aerogels consisting of graphitic-carbon nitride (g-C 3 N 4 ) modified with a perylene imide (PI) and graphene oxide (GO) are prepared for nitric oxide (NO) removal under visible-light irradiation. All of the photocatalysts exhibit excellent activity in NO removal because of the strong light absorption and good planarity of PI-g-C 3 N 4 coupled with the favorable charge transport properties of GO, which slow the recombination of electron-hole pairs. The aerogel containing thiophene displays the most efficient NO removal of the aerogel series, with a removal ratio of up to 66%. Density functional theory calculations are conducted to explain this result and recycling experiments are carried out to verify the stability and recyclability of these photocatalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermal-mechanical modeling of laser ablation hybrid machining

NASA Astrophysics Data System (ADS)

Matin, Mohammad Kaiser

2001-08-01

Hard, brittle and wear-resistant materials like ceramics pose a problem when being machined using conventional machining processes. Machining ceramics even with a diamond cutting tool is very difficult and costly. Near net-shape processes, like laser evaporation, produce micro-cracks that require extra finishing. Thus it is anticipated that ceramic machining will have to continue to be explored with new-sprung techniques before ceramic materials become commonplace. This numerical investigation results from the numerical simulations of the thermal and mechanical modeling of simultaneous material removal from hard-to-machine materials using both laser ablation and conventional tool cutting utilizing the finite element method. The model is formulated using a two dimensional, planar, computational domain. The process simulation acronymed, LAHM (Laser Ablation Hybrid Machining), uses laser energy for two purposes. The first purpose is to remove the material by ablation. The second purpose is to heat the unremoved material that lies below the ablated material in order to ``soften'' it. The softened material is then simultaneously removed by conventional machining processes. The complete solution determines the temperature distribution and stress contours within the material and tracks the moving boundary that occurs due to material ablation. The temperature distribution is used to determine the distance below the phase change surface where sufficient ``softening'' has occurred, so that a cutting tool may be used to remove additional material. The model incorporated for tracking the ablative surface does not assume an isothermal melt phase (e.g. Stefan problem) for laser ablation. Both surface absorption and volume absorption of laser energy as function of depth have been considered in the models. LAHM, from the thermal and mechanical point of view is a complex machining process involving large deformations at high strain rates, thermal effects of the laser, removal of materials and contact between workpiece and tool. The theoretical formulation associated with LAHM for solving the thermal-mechanical problem using the finite element method is presented. The thermal formulation is incorporated in the user defined subroutines called by ABAQUS/Standard. The mechanical portion is modeled using ABAQUS/Explicit's general capabilities of modeling interactions involving contact and separation. The results obtained from the FEA simulations showed that the cutting force decrease considerably in both LAEM Surface Absorption (LARM-SA) and LAHM volume absorption (LAHM-VA) models relative to LAM model. It was observed that the HAZ can be expanded or narrowed depending on the laser speed and power. The cutting force is minimal at the last extent of the HAZ. In both the models the laser ablates material thus reducing material stiffness as well as relaxing the thermal stress. The stress values obtained showed compressive yield stress just below the ablated surface and chip. The failure occurs by conventional cutting where tensile stress exceeds the tensile strength of the material at that temperature. In this hybrid machining process the advantages of both the individual machining processes were realized.

Environmental application of biochar: Current status and perspectives.

PubMed

Oliveira, Fernanda R; Patel, Anil K; Jaisi, Deb P; Adhikari, Sushil; Lu, Hui; Khanal, Samir Kumar

2017-12-01

In recent years, there has been a significant interest on biochar for various environmental applications, e.g., pollutants removal, carbon sequestration, and soil amelioration. Biochar has several unique properties, which makes it an efficient, cost-effective and environmentally-friendly material for diverse contaminants removal. The variability in physicochemical properties (e.g., surface area, microporosity, and pH) provides an avenue for biochar to maximize its efficacy to targeted applications. This review aims to highlight the vital role of surface architecture of biochar in different environmental applications. Particularly, it provides a critical review of current research updates related to the pollutants interaction with surface functional groups of biochars and the effect of the parameters variability on biochar attributes pertinent to specific pollutants removal, involved mechanisms, and competence for these removals. Moreover, future research directions of biochar research are also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of different surface materials on runoff quality in permeable pavement systems.

PubMed

Li, Haiyan; Li, Zhifei; Zhang, Xiaoran; Li, Zhuorong; Liu, Dongqing; Li, Tanghu; Zhang, Ziyang

2017-09-01

To investigate the effect of different permeable pavement surface materials on the removal of pollutants from urban storm-runoff, six commonly surface materials (porous asphalt, porous concrete, cement brick, ceramic brick, sand base brick, and shale brick) were selected in this study and the research was carried out by column experiments. Except the concentrations of total suspended solids (TSS), chemical oxygen demand (COD), ammonia nitrogen (NH 4 -N), nitrate nitrogen (NO 3 -N), total nitrogen (TN), and total phosphorus (TP) in the influent and effluent that were measured, the removal mechanism of pollutants was discussed further. The results indicate that the surface materials influence the removal efficiency of pollutants greatly and have different effects on certain pollutant. Furthermore, the physical interception and adsorption would be the main mechanism for the removal of pollutants from runoff. For example, for all surface materials, the average removal efficiency of TSS is nearly about 90.0% because of physical interception. Due to the amount of iron oxide, the removal efficiency of COD, NO 3 -N, and TN of shale brick was 88.2, 35.1, and 17.5%, respectively. NH 4 -N and TN can be easily removed by porous asphalt due to the high content of organic matter. By lacking of useful adsorption sites, all the surface materials had little effect on the removal of TP from runoff. This research could offer useful guidelines for the better design of permeable pavement system and promote the insight into the removal mechanism of pollutants in permeable pavement system. Graphical abstract Different types of materials for the different types of pollutants in the runoff purification capacity were significantly different, overall, shale brick and porous asphalt Shale bricks and porous asphalt have a better purification effect according to the six kinds of materials.

Space station molecular sieve development

NASA Technical Reports Server (NTRS)

Chang, C.; Rousseau, J.

1986-01-01

An essential function of a space environmental control system is the removal of carbon dioxide (CO2) from the atmosphere to control the partial pressure of this gas at levels lower than 3 mm Hg. The use of regenerable solid adsorbents for this purpose was demonstrated effectively during the Skylab mission. Earlier sorbent systems used zeolite molecular sieves. The carbon molecular sieve is a hydrophobic adsorbent with excellent potential for space station application. Although carbon molecular sieves were synthesized and investigated, these sieves were designed to simulate the sieving properties of 5A zeolite and for O2/N2 separation. This program was designed to develop hydrophobic carbon molecular sieves for CO2 removal from a space station crew environment. It is a first phase effort involved in sorbent material development and in demonstrating the utility of such a material for CO2 removal on space stations. The sieve must incorporate the following requirements: it must be hydrophobic; it must have high dynamic capacity for carbon dioxide at the low partial pressure of the space station atmosphere; and it must be chemiclly stable and will not generate contaminants.

Process parameter effects on material removal in magnetorheological finishing of borosilicate glass.

PubMed

Miao, Chunlin; Lambropoulos, John C; Jacobs, Stephen D

2010-04-01

We investigate the effects of processing parameters on material removal for borosilicate glass. Data are collected on a magnetorheological finishing (MRF) spot taking machine (STM) with a standard aqueous magnetorheological (MR) fluid. Normal and shear forces are measured simultaneously, in situ, with a dynamic dual load cell. Shear stress is found to be independent of nanodiamond concentration, penetration depth, magnetic field strength, and the relative velocity between the part and the rotating MR fluid ribbon. Shear stress, determined primarily by the material mechanical properties, dominates removal in MRF. The addition of nanodiamond abrasives greatly enhances the material removal efficiency, with the removal rate saturating at a high abrasive concentration. The volumetric removal rate (VRR) increases with penetration depth but is insensitive to magnetic field strength. The VRR is strongly correlated with the relative velocity between the ribbon and the part, as expected by the Preston equation. A modified removal rate model for MRF offers a better estimation of MRF removal capability by including nanodiamond concentration and penetration depth.

Design and Synthesis of Self-Assembled Monolayers on Mesoporous Supports (SAMMS): The Importance of Ligand Posture in Functional Nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fryxell, Glen E.; Mattigod, Shas V.; Lin, Yuehe

2007-07-01

Water, and water quality, are issues of critical importance to the future of humankind. The Earth’s water supplies have been contaminated by a wide variety of industrial, military and natural sources. The need exists for an efficient separation technology to remove heavy metal and radionuclide contamination from water. Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to build high efficiency environmental sorbents. These nanoporous ceramics condense a huge amount of surface area into a very small volume. These mesoporous architectures can be subsequently functionalized through molecular self-assembly. These functional mesoporous materials offer significant capabilities in termsmore » of removal of heavy metals and radionuclides from a variety of liquid media, including groundwater, contaminated oils and contaminated chemical weapons. They are highly efficient sorbents, whose rigid, open pore structure allows for rapid, efficient sorption kinetics. Their interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometallate anions and radionuclides. This manuscript provides a review of the design, synthesis and performance of the sorbent materials. The role that ligand posture plays in the chemistry of these interfacial ligand fields is discussed.« less

Removal of heavy metals from aqueous systems with thiol functionalized superparamagnetic nanoparticles.

PubMed

Yantasee, Wassana; Warner, Cynthia L; Sangvanich, Thanapon; Addleman, R Shane; Carter, Timothy G; Wiacek, Robert J; Fryxell, Glen E; Timchalk, Charles; Warner, Marvin G

2007-07-15

We have shown that superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) are an effective sorbent material for toxic soft metals such as Hg, Ag, Pb, Cd, and Tl, which effectively bind to the DMSA ligands and for As, which binds to the iron oxide lattices. The nanoparticles are highly dispersible and stable in solutions, have a large surface area (114 m2/g), and have a high functional group content (1.8 mmol thiols/g). They are attracted to a magnetic field and can be separated from solution within a minute with a 1.2 T magnet. The chemical affinity, capacity, kinetics, and stability of the magnetic nanoparticles were compared to those of conventional resin based sorbents (GT-73), activated carbon, and nanoporous silica (SAMMS) of similar surface chemistries in river water, groundwater, seawater, and human blood and plasma. DMSA-Fe3O4 had a capacity of 227 mg of Hg/g, a 30-fold larger value than GT-73. The nanoparticles removed 99 wt% of 1 mg/L Pb within a minute, while it took over 10 and 120 min for Chelex-100 and GT-73 to remove 96% of Pb.

Porous graphene materials for water remediation.

PubMed

Niu, Zhiqiang; Liu, Lili; Zhang, Li; Chen, Xiaodong

2014-09-10

Water remediation has been a critical issue over the past decades due to the expansion of wastewater discharge to the environment. Currently, a variety of functional materials have been successfully prepared for water remediation applications. Among them, graphene is an attractive candidate due to its high specific surface area, tunable surface behavior, and high strength. This Concept paper summarizes the design strategy of porous graphene materials and their applications in water remediation, such as the cleanup of oil, removal of heavy metal ions, and elimination of water soluble organic contaminants. The progress made so far will guide further development in structure design strategy of porous materials based on graphene and exploration of such materials in environmental remediation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selective removal of esthetic composite restorations with spectral guided laser ablation

NASA Astrophysics Data System (ADS)

Yi, Ivana; Chan, Kenneth H.; Tsuji, Grant H.; Staninec, Michal; Darling, Cynthia L.; Fried, Daniel

2016-02-01

Dental composites are used for a wide range of applications such as fillings for cavities, adhesives for orthodontic brackets, and closure of gaps (diastemas) between teeth by esthetic bonding. Anterior restorations are used to replace missing, diseased and unsightly tooth structure for both appearance and function. When these restorations must be replaced, they are difficult to remove mechanically without causing excessive removal or damage to enamel because dental composites are color matched to teeth. Previous studies have shown that CO2 lasers have high ablation selectivity and are well suited for removal of composite on occlusal surfaces while minimizing healthy tissue loss. A spectral feedback guidance system may be used to discriminate between dental composite and dental hard tissue for selective ablation of composite material. The removal of composite restorations filling diastemas is more challenging due to the esthetic concern for anterior teeth. The objective of this study is to determine if composite spanning a diastema between anterior teeth can be removed by spectral guided laser ablation at clinically relevant rates with minimal damage to peripheral healthy tissue and with higher selectivity than a high speed dental handpiece.

Application of Colloidal Filtration Theory on Textile Fibrous Media: Effect of Fiber Orientation on Bacterial Removal Efficiency and Attachment

NASA Astrophysics Data System (ADS)

Roy, Sukumar; Ghosh, Subrata; Bhowmick, Niranjan

2018-06-01

A mechanism to remove the Pseudomonas bacteria from contaminated water by using textile fibrous media has been proposed in this article. The attachment of Pseudomonas bacteria on nylon fibrous media was studied in laboratory column experiment. A systematic study was carried out to investigate the attachment of bacteria on the fibrous material as a function of fiber orientation to the direction of the liquid flow. Three types of textiles media with different orientation fiber were selected for the experiment (i.e. 0°, 45° and 90°). It was found that the bacteria removal efficiency was comparatively higher at 90° orientation as compared to that of 45° and 0° orientation of fibrous media, suggesting that the removal efficiency of bacteria (1 - Fp) was depended on fiber orientation. The removal trends were explained on the basis of colloidal filtration theory. This is due to the higher single collector contact efficiency and attachment/collision efficiency as observed from the experimental data of removal efficiency.

Application of Colloidal Filtration Theory on Textile Fibrous Media: Effect of Fiber Orientation on Bacterial Removal Efficiency and Attachment

NASA Astrophysics Data System (ADS)

Roy, Sukumar; Ghosh, Subrata; Bhowmick, Niranjan

2018-05-01

A mechanism to remove the Pseudomonas bacteria from contaminated water by using textile fibrous media has been proposed in this article. The attachment of Pseudomonas bacteria on nylon fibrous media was studied in laboratory column experiment. A systematic study was carried out to investigate the attachment of bacteria on the fibrous material as a function of fiber orientation to the direction of the liquid flow. Three types of textiles media with different orientation fiber were selected for the experiment (i.e. 0°, 45° and 90°). It was found that the bacteria removal efficiency was comparatively higher at 90° orientation as compared to that of 45° and 0° orientation of fibrous media, suggesting that the removal efficiency of bacteria (1 - Fp) was depended on fiber orientation. The removal trends were explained on the basis of colloidal filtration theory. This is due to the higher single collector contact efficiency and attachment/collision efficiency as observed from the experimental data of removal efficiency.

Material appearance acquisition from a single image

NASA Astrophysics Data System (ADS)

Zhang, Xu; Cui, Shulin; Cui, Hanwen; Yang, Lin; Wu, Tao

2017-01-01

The scope of this paper is to present a method of material appearance acquisition(MAA) from a single image. In this paper, material appearance is represented by spatially varying bidirectional reflectance distribution function(SVBRDF). Therefore, MAA can be reduced to the problem of recovery of each pixel's BRDF parameters from an original input image, which include diffuse coefficient, specular coefficient, normal and glossiness based on the Blinn-Phone model. In our method, the workflow of MAA includes five main phases: highlight removal, estimation of intrinsic images, shape from shading(SFS), initialization of glossiness and refining SVBRDF parameters based on IPOPT. The results indicate that the proposed technique can effectively extract the material appearance from a single image.

Biodegradable Materials and Metallic Implants—A Review

PubMed Central

Prakasam, Mythili; Locs, Janis; Salma-Ancane, Kristine; Loca, Dagnija; Largeteau, Alain; Berzina-Cimdina, Liga

2017-01-01

Recent progress made in biomaterials and their clinical applications is well known. In the last five decades, great advances have been made in the field of biomaterials, including ceramics, glasses, polymers, composites, glass-ceramics and metal alloys. A variety of bioimplants are currently used in either one of the aforesaid forms. Some of these materials are designed to degrade or to be resorbed inside the body rather than removing the implant after its function is served. Many properties such as mechanical properties, non-toxicity, surface modification, degradation rate, biocompatibility, and corrosion rate and scaffold design are taken into consideration. The current review focuses on state-of-the-art biodegradable bioceramics, polymers, metal alloys and a few implants that employ bioresorbable/biodegradable materials. The essential functions, properties and their critical factors are discussed in detail, in addition to their challenges to be overcome. PMID:28954399

Biodegradable Materials and Metallic Implants-A Review.

PubMed

Prakasam, Mythili; Locs, Janis; Salma-Ancane, Kristine; Loca, Dagnija; Largeteau, Alain; Berzina-Cimdina, Liga

2017-09-26

Recent progress made in biomaterials and their clinical applications is well known. In the last five decades, great advances have been made in the field of biomaterials, including ceramics, glasses, polymers, composites, glass-ceramics and metal alloys. A variety of bioimplants are currently used in either one of the aforesaid forms. Some of these materials are designed to degrade or to be resorbed inside the body rather than removing the implant after its function is served. Many properties such as mechanical properties, non-toxicity, surface modification, degradation rate, biocompatibility, and corrosion rate and scaffold design are taken into consideration. The current review focuses on state-of-the-art biodegradable bioceramics, polymers, metal alloys and a few implants that employ bioresorbable/biodegradable materials. The essential functions, properties and their critical factors are discussed in detail, in addition to their challenges to be overcome.

Polyethyleneimine-carbon nanotube polymeric nanocomposite adsorbents for the removal of Cr6+ from water

NASA Astrophysics Data System (ADS)

Sambaza, Shepherd S.; Masheane, Monaheng L.; Malinga, Soraya P.; Nxumalo, Edward N.; Mhlanga, Sabelo D.

2017-08-01

This work reports on the synthesis of multi-walled carbon nanotubes (MWCNTs) and their use in branched polyethyleneimine-multiwalled carbon nanotube (PEI-MWCNT) polymeric nanocomposite adsorbents for the removal of Cr6+ from contaminated water. The nanostructured materials were characterized using TEM, Raman, FTIR, BET surface area and zeta potential measurements. TEM confirmed the average diameter of the MWCNTs to be 25 nm. The point of zero-charge of PEI was at pH 8 and that of PEI-MWCNTs was at pH 7.7. FTIR analysis confirmed the formation of a new bond (-Cdbnd O at 1716 cm-1) between the functional groups on the MWCNTs and PEI. Batch adsorption and kinetic studies showed that the PEI-MWCNT nanocomposite materials were more efficient in the removal of Cr6+ solution from water samples. The optimum conditions for adsorption were pH ≤ 4, contact time of 60 min. When the PEI-MWCNT dosage was increased the adsorption capacity increased. The kinetic adsorption data obtained for Cr6+ solution followed pseudo-second order model. The adsorption of Cr6+ solution reached equilibrium within 60 min of contact time with a removal of 99%. The adsorbents were effective even after 5 cycles of use.

Efficient adsorption of multiple heavy metals with tailored silica aerogel-like materials.

PubMed

Vareda, João P; Durães, Luisa

2017-11-10

Recently developed tailored adsorbents for heavy metal uptake are studied in batch tests with Cu, Pb, Cd, Ni, Cr and Zn, in order to decontaminate polluted environments where these heavy metals are found in solution - water courses and groundwater. The adsorbents feature mercapto or amine-mercapto groups that are capable of complexating the cations. Through the use of equilibrium tests it is found that a remarkably high heavy metal uptake is obtained for all metals (ranging from 84 to 140 mg/g). These uptake values are quite impressive when compared to other adsorbents reported in the literature, which is also due to the double functionalization present in one of the adsorbents. For the best adsorbent, adsorption capacities followed the order Cu(II) > Pb(II) > Zn(II) > Cr(III) > Cd(II) > Ni(II). With these adsorbents, the removal process was fast with most of the metals being removed in less than 1 h. Competitive sorption tests were performed in tertiary mixtures that were based on real world polluted sites. It was found that although competitive sorption occurs, affecting the individual removal of each metal, all the cations in solution still interact with the adsorbent, achieving removal values that make this type of material very interesting for its proposed application.

Selective Familiarity Deficits after Left Anterior Temporal-Lobe Removal with Hippocampal Sparing Are Material Specific

ERIC Educational Resources Information Center

Martin, Chris B.; Bowles, Ben; Mirsattari, Seyed M.; Kohler, Stefan

2011-01-01

Research has firmly established a link between recognition memory and the functional integrity of the medial temporal lobes (MTL). Dual-process models of MTL organization maintain that there is a division of labour within the MTL, with the hippocampus (HC) supporting recollective processes and perirhinal cortex (PRc) supporting familiarity…

Small-diameter trees used for chemithermomechanical pulps.

Treesearch

Gary C. Myers; R. James Barbour; Said M. AbuBakr

2003-01-01

To restore and maintain forest ecosystem health and function in the western interior of the United States, many small-diameter stems need to be removed from densely stocked stands. In general, these materials are underutilized. Information on the properties of these resources is needed to help forest managers understand when timber sales are a viable option to...

The role of fire in management of watershed responses

Treesearch

Malcolm J. Zwolinski

2000-01-01

Hydrologic responses of watersheds are strongly related to vegetation and soil disturbances. Many of the storage and transfer components of the global hydrologic cycle are altered by the occurrence of fire. The major effect of fire on the hydrologic functioning of watersheds is the removal of vegetation and litter materials that protect the soil surface. Reductions in...

Method of removing contaminants from plastic resins

DOEpatents

Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

2008-11-18

A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

Method of removing contaminants from plastic resins

DOEpatents

Bohnert, George W [Harrisonville, MO; Hand, Thomas E [Lee's Summit, MO; Delaurentiis, Gary M [Jamestown, CA

2007-08-07

A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

Method for removing contaminants from plastic resin

DOEpatents

Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

2008-12-30

A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

Performance of mesoporous organosilicates on the adsorption of heavy oil from produced water

NASA Astrophysics Data System (ADS)

Twaiq, Farouq A.; Nasser, Mustafa S.; Al-Ryiami, Samyia; Al-Ryiami, Hanan

2012-09-01

The performance of mesoporous organosilicate materials in removal of soluble oil from wastewater is investigated. The aim of the study is to evaluate the oil adsorption over organosilicate prepared using pre-synthesis methods and compare the results with adsorption over pure siliceous mesoporous material. The materials were prepared using sol-gel technique using Dodecylamine (D) and Cetyltrimethylammonium bromide (CTAB) as surfactant templates, and Tetraethylorthosilicate (TEOS) as silica precursor. The as-synthesized mesoporous materials were treated using three different methods to remove the surfactant from the mesoporous silica including calcinations method for total removal of the surfactant, the water vapor stripping and ethanol vapor stripping were used for partial removal of the surfactants. The synthesized materials were characterized using X-ray diffraction (XRD) and nitrogen adsorption. The materials were tested for heavy oils removal from oil-water solution. The results showed that neutral surfactant organosilicates have less adsorption compare to cationic surfactant organosilicates. The results also showed that among organosilicates prepared using neutral surfactant, treated organosilicate by ethanol vapor have the highest activity in removing the oil from the oil-water solution.

Immobilized materials for removal of toxic metal ions from surface/groundwaters and aqueous waste streams.

PubMed

Zawierucha, Iwona; Kozlowski, Cezary; Malina, Grzegorz

2016-04-01

Heavy metals from industrial processes are of special concern because they produce chronic poisoning in the aquatic environment. More strict environmental regulations on the discharge of toxic metals require the development of various technologies for their removal from polluted streams (i.e. industrial wastewater, mine waters, landfill leachate, and groundwater). The separation of toxic metal ions using immobilized materials (novel sorbents and membranes with doped ligands), due to their high selectivity and removal efficiency, increased stability, and low energy requirements, is promising for improving the environmental quality. This critical review is aimed at studying immobilized materials as potential remediation agents for the elimination of numerous toxic metal (e.g. Pb, Cd, Hg, and As) ions from polluted streams. This study covers the general characteristics of immobilized materials and separation processes, understanding of the metal ion removal mechanisms, a review of the application of immobilized materials for the removal of toxic metal ions, as well as the impacts of various parameters on the removal efficiency. In addition, emerging trends and opportunities in the field of remediation technologies using these materials are addressed.

Grinding model and material removal mechanism of medical nanometer zirconia ceramics.

PubMed

Zhang, Dongkun; Li, Changhe; Jia, Dongzhou; Wang, Sheng; Li, Runze; Qi, Xiaoxiao

2014-01-01

Many patents have been devoted to developing medical nanometer zirconia ceramic grinding techniques that can significantly improve both workpiece surface integrity and grinding quality. Among these patents is a process for preparing ceramic dental implants with a surface for improving osseo-integration by sand abrasive finishing under a jet pressure of 1.5 bar to 8.0 bar and with a grain size of 30 µm to 250 µm. Compared with other materials, nano-zirconia ceramics exhibit unmatched biomedical performance and excellent mechanical properties as medical bone tissue and dentures. The removal mechanism of nano-zirconia materials includes brittle fracture and plastic removal. Brittle fracture involves crack formation, extension, peeling, and chipping to completely remove debris. Plastic removal is similar to chip formation in metal grinding, including rubbing, ploughing, and the formation of grinding debris. The materials are removed in shearing and chipping. During brittle fracture, the grinding-led transverse and radial extension of cracks further generate local peeling of blocks of the material. In material peeling and removal, the mechanical strength and surface quality of the workpiece are also greatly reduced because of crack extension. When grinding occurs in the plastic region, plastic removal is performed, and surface grinding does not generate grinding fissures and surface fracture, producing clinically satisfactory grinding quality. With certain grinding conditions, medical nanometer zirconia ceramics can be removed through plastic flow in ductile regime. In this study, we analyzed the critical conditions for the transfer of brittle and plastic removal in nano-zirconia ceramic grinding as well as the high-quality surface grinding of medical nanometer zirconia ceramics by ELID grinding.

Laser Processing of Carbon Nanotube Transparent Conducting Films

NASA Astrophysics Data System (ADS)

Mann, Andrew

Transparent conducting films, or TCFs, are 2D electrical conductors with the ability to transmit light. Because of this, they are used in many popular electronics including smart phones, tablets, solar panels, and televisions. The most common material used as a TCF is indium tin oxide, or ITO. Although ITO has great electrical and optical characteristics, it is expensive, brittle, and difficult to pattern. These limitations have led researchers toward other materials for the next generation of displays and touch panels. The most promising material for next generation TCFs is carbon nanotubes, or CNTs. CNTs are cylindrical tubes of carbon no more than a few atoms thick. They have different electrical and optical properties depending on their atomic structure, and are extremely strong. As an electrode, they conduct electricity through an array of randomly dispersed tubes. The array is highly transparent because of gaps between the tubes, and size and optical properties of the CNTs. Many research groups have tried making CNT TCFs with opto-electric properties similar to ITO but have difficultly achieving high conductivity. This is partly attributed to impurities from fabrication and a mix of different tube types, but is mainly caused by low junction conductivity. In functionalized nanotubes, junction conductivity is impaired by covalently bonded molecules added to the sidewalls of the tubes. The addition of this molecule, known as functionalization, is designed to facilitate CNT dispersion in a solvent by adding properties of the molecule to the CNTs. While necessary for a good solution, functionalization decreases the conductivity in the CNT array by creating defects in the tube's structures and preventing direct inter-carbon bonding. This research investigates removing the functional coating (after tube deposition) by laser processing. Laser light is able to preferentially heat the CNTs because of their optical and electrical properties. Through local conduction, the relatively weak functional molecules are thermally decomposed. This restores the pristine CNT structure and allows carbon to carbon bonds to form; thereby significantly improving the junction and sheet conductivity. Laser processing is performed without damaging the TCF substrate (usually glass or PET) because laser light is not absorbed by the substrate and conduction from the CNTs is limited. In addition to removing the functional coating, laser light improves the electrical conductivity by purifying the CNT array. The purity is improved through the ablation of defective tubes and amorphous carbon in the CNT film.[1] Using higher laser power, it is possible to locally remove the CNTs. Selective laser removal of the CNTs is a dry process that can be used to pattern the electrode. This is a much simpler and less expensive patterning technique than wet acid etching used for ITO. In summary, laser processing of CNT TCFs is shown to improve the electrical conductivity by defunctionalizing the CNTs. In addition, laser exposure increases purity by removing defects and can be used to pattern the electrode. These advances make CNTs more competitive as an alternative for ITO which has both cost and performance limitations. [1] T. Ueda, S. K. (2008). Effect of laser irradiation on carbon nanotube films for NOx gas sensor. Surface & Coatings Technology, 202, 5325--5328.

Dielectric function of InGaAs in the visible

NASA Technical Reports Server (NTRS)

Alterovitz, S. A.; Sieg, R. E.; Yao, H. D.; Snyder, P. G.; Woollam, J. A.; Pamulapati, J.; Bhattacharya, P. K.; Sekula-Moise, P. A.

1990-01-01

Measurements are reported of the dielectric function of thermodynamically stable In(x)Ga(1-x)As in the composition range 0.3 equal to or less than X = to or less than 0.7. The optically thick samples of InGaAs were made by molecular beam epitaxy (MBE) in the range 0.4 = to or less than X = to or less than 0.7 and by metal-organic chemical vapor deposition (MOCVD) for X = 0.3. The MBE made samples, usually 1 micron thick, were grown on semi-insulating InP and included a strain release structure. The MOCVD sample was grown on GaAs and was 2 microns thick. The dielectric functions were measured by variable angle spectroscopic ellipsometry in the range 1.55 to 4.4 eV. The data was analyzed assuming an optically thick InGaAs material with an oxide layer on top. The thickness of this layer was estimated by comparing the results for the InP lattice matched material, i.e., X = 0.53, with results published in the literature. The top oxide layer mathematically for X = 0.3 and X = 0.53 was removed to get the dielectric function of the bare InGaAs. In addition, the dielectric function of GaAs in vacuum, after a protective arsenic layer was removed. The dielectric functions for X = 0, 0.3, and 0.53 together with the X = 1 result from the literature to evaluate an algorithm for calculating the dielectric function of InGaAs for an arbitrary value of X(0 = to or less than X = to or less than 1) were used. Results of the dielectric function calculated using the algorithm were compared with experimental data.

Dielectric function of InGaAs in the visible

NASA Technical Reports Server (NTRS)

Alterovitz, S. A.; Yao, H. D.; Snyder, P. G.; Woolam, J. A.; Pamulapati, J.; Bhattacharya, P. K.; Sekula-Moise, P. A.; Sieg, R. E.

1990-01-01

Measurements are reported of the dielectric function of thermodynamically stable In(x)Ga(1-x)As in the composition range 0.3 equal to or less than X = to or less than 0.7. The optically thick samples of InGaAs were made by molecular beam epitaxy (MBE) in the range 0.4 = to or less than X = to or less than 0.7 and by metal-organic chemical vapor deposition (MOCVD) for X = 0.3. The MBE made samples, usually 1 micron thick, were grown on semi-insulating InP and included a strain release structure. The MOCVD sample was grown on GaAs and was 2 microns thick. The dielectric functions were measured by variable angle spectroscopic ellipsometry in the range 1.55 to 4.4 eV. The data was analyzed assuming an optically thick InGaAs material with an oxide layer on top. The thickness of this layer was estimated by comparing the results for the InP lattice matched material, i.e., X = 0.53, with results published in the literature. The top oxide layer mathematically for X = 0.3 and X = 0.53 was removed to get the dielectric function of the bare InGaAs. In addition, the dielectric function of GaAs in vacuum, after a protective arsenic layer was removed. The dielectric functions for X = 0, 0.3, and 0.53 together with the X = 1 result from the literature to evaluate an algorithm for calculating the dielectric function of InGaAs for an arbitrary value of X (0 = to or less than X = to or less than 1) were used. Results of the dielectric function calculated using the algorithm were compared with experimental data.

Solid materials for removing arsenic and method thereof

DOEpatents

Coronado, Paul R.; Coleman, Sabre J.; Sanner, Robert D.; Dias, Victoria L.; Reynolds, John G.

2010-09-28

Solid materials have been developed to remove arsenic compounds from aqueous media. The arsenic is removed by passing the aqueous phase through the solid materials which can be in molded, granular, or powder form. The solid materials adsorb the arsenic leaving a purified aqueous stream. The materials are aerogels or xerogels and aerogels or xerogels and solid support structure, e.g., granulated activated carbon (GAC), mixtures. The species-specific adsorption occurs through specific chemical modifications of the solids tailored towards arsenic.

Solid materials for removing arsenic and method thereof

DOEpatents

Coronado, Paul R [Livermore, CA; Coleman, Sabre J [Oakland, CA; Sanner, Robert D [Livermore, CA; Dias, Victoria L [Livermore, CA; Reynolds, John G [San Ramon, CA

2008-07-01

Solid materials have been developed to remove arsenic compounds from aqueous media. The arsenic is removed by passing the aqueous phase through the solid materials which can be in molded, granular, or powder form. The solid materials adsorb the arsenic leaving a purified aqueous stream. The materials are aerogels or xerogels and aerogels or xerogels and solid support structure, e.g., granulated activated carbon (GAC), mixtures. The species-specific adsorption occurs through specific chemical modifications of the solids tailored towards arsenic.

Organic contaminant removal efficiency of sodium bentonite/clay (BC) mixtures in high permeability regions utilizing reclaimed wastewater: A meso-scale study

NASA Astrophysics Data System (ADS)

Xiao, Yang; Li, Yunkai; Ning, Zigong; Li, Pengxiang; Yang, Peiling; Liu, Chengcheng; Liu, Zhongwei; Xu, Feipeng; Hynds, Paul Dylan

2018-03-01

Wastewater reclamation now represents an effective measure for sustainable water resource management in arid regions, however wastewater components (organic micropollutants) may potentially impact local ecological and/or human health. Previous studies have shown that sodium bentonite/natural clay (BC) mixes may be used to effectively reduce riverbed infiltration in regions characterized by excessively high hydraulic conductivity. Accordingly, the current study sought to investigate the contaminant removal efficiency (Re) of several BC mass ratios in simulated dry riverbeds. Results indicate that the measured Re of NH4+-N, CODcr and BOD5 increased in concurrence with an increasing sodium bentonite ratio, up to a maximum Re of 97.4% (NH4+-N), 55.2% (CODcr), and 51.5% (BOD5). The primary contaminant removal site was shown to be the infiltration-reducing (BC) layer, accounting for approximately 40%, 60%, and 70% of NH4+-N, CODcr and BOD5 removal, respectively. Conversely, the removal efficiency of NO3-N was found to be low (<15%), while total phosphorous (TP) was found to actively leach from the infiltration-reduction layer, resulting in measured TP discharges 2.4-4.8 times those of initial infiltration values. The current study provides a technical baseline for the efficacy of sodium bentonite as an effective bi-functional material in areas utilizing reclaimed water i.e. concurrent reduction of infiltration rates (Function 1) and decontamination of reclaimed wastewater infiltration/recharge (Function 2). Findings indicate that sodium bentonite-clay mixes may represent a feasible alternative for managing recharge of non-potable aquifers with reclaimed wastewater.

Nondimensional parameter for conformal grinding: combining machine and process parameters

NASA Astrophysics Data System (ADS)

Funkenbusch, Paul D.; Takahashi, Toshio; Gracewski, Sheryl M.; Ruckman, Jeffrey L.

1999-11-01

Conformal grinding of optical materials with CNC (Computer Numerical Control) machining equipment can be used to achieve precise control over complex part configurations. However complications can arise due to the need to fabricate complex geometrical shapes at reasonable production rates. For example high machine stiffness is essential, but the need to grind 'inside' small or highly concave surfaces may require use of tooling with less than ideal stiffness characteristics. If grinding generates loads sufficient for significant tool deflection, the programmed removal depth will not be achieved. Moreover since grinding load is a function of the volumetric removal rate the amount of load deflection can vary with location on the part, potentially producing complex figure errors. In addition to machine/tool stiffness and removal rate, load generation is a function of the process parameters. For example by reducing the feed rate of the tool into the part, both the load and resultant deflection/removal error can be decreased. However this must be balanced against the need for part through put. In this paper a simple model which permits combination of machine stiffness and process parameters into a single non-dimensional parameter is adapted for a conformal grinding geometry. Errors in removal can be minimized by maintaining this parameter above a critical value. Moreover, since the value of this parameter depends on the local part geometry, it can be used to optimize process settings during grinding. For example it may be used to guide adjustment of the feed rate as a function of location on the part to eliminate figure errors while minimizing the total grinding time required.

Graphitic Carbon Materials Tailored for the Rapid Adsorption of Biomolecules

NASA Astrophysics Data System (ADS)

Pescatore, Nicholas A.

Sepsis is an overactive inflammatory response to an infection, with 19 million cases estimated worldwide and causing organ dysfunction if left untreated. Three pro-inflammatory cytokines are seen from literature review as vital biomarkers for sepsis and are interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha), which have the potential to be removed by hemoperfusion. This thesis examines carbon nanomaterials for their adsorption capabilities in the search for an optimal material for blood cleansing hemoperfusion application, such as mediating the effects of sepsis. Non-porous and porous carbon polymorphs and their properties are investigated in this thesis for their protein adsorption capabilities. Polymer-derived mesoporous carbons were compared to non-porous graphene nanoplatelets (GNP's) to observe changes in adsorption capacity for cytokines between porous and non-porous materials. GNP's were functionalized via high temperature vacuum annealing, air oxidation, acid oxidation and amination treatments to understand the effect of surface chemistry on adsorption. For practical use in a hemoperfusion column, polymer-derived carbon beads and composite materials such as cryogel and PTFE-GNP composites were designed and tested for their adsorption capacity. At concentrations of IL-6, IL-8, and TNF-alpha seen in septic patients, these cytokines were completely removed from the blood after 5 minutes of incubation with GNP's. Overall, a low-cost, scalable carbon adsorbent was found to provide a novel approach of rapidly removing pro-inflammatory cytokines from septic patients.

Iron oxide inside SBA-15 modified with amino groups as reusable adsorbent for highly efficient removal of glyphosate from water

NASA Astrophysics Data System (ADS)

Fiorilli, Sonia; Rivoira, Luca; Calì, Giada; Appendini, Marta; Bruzzoniti, Maria Concetta; Coïsson, Marco; Onida, Barbara

2017-07-01

Iron oxide clusters were incorporated into amino-functionalized SBA-15 in order to obtain a magnetically recoverable adsorbent. The physical-chemical properties of the material were characterized by FE-SEM, STEM, XRD, TGA, XPS, FT-IR and acid-base titration analysis. Iron oxide nanoparticles were uniformly dispersed into the pore of mesoporous silica and that the adsorbent is characterized high specific surface area (177 m2/g) and accessible porosity. The sorbent was successfully tested for the removal of glyphosate in real water matrices. Despite the significant content of inorganic ions, a quantitative removal of the contaminant was found. The complete regeneration of the sorbent after the adsorption process through diluted NaOH solution was also proved.

Comparative renal anatomy of exotic species.

PubMed

Holz, Peter H; Raidal, Shane R

2006-01-01

All living organisms consume nutrients that are required for the production of both tissue and energy. The waste products of this process include nitrogenous materials and inorganic salts. They are removed from the body by excretory organs, which in vertebrate shave developed into kidneys and into salt glands in some birds and reptiles. Many invertebrates use a series of excretory organs called nephridia to perform the same function. Even though they perform similar functions, there is no evolutionary connection between invertebrate nephridia and vertebrate kidneys. Both evolved independently.

Templated Assembly of a Functional Ordered Protein Macromolecular Framework from P22 Virus-like Particles.

PubMed

McCoy, Kimberly; Uchida, Masaki; Lee, Byeongdu; Douglas, Trevor

2018-04-24

Bottom-up construction of mesoscale materials using biologically derived nanoscale building blocks enables engineering of desired physical properties using green production methods. Virus-like particles (VLPs) are exceptional building blocks due to their monodispersed sizes, geometric shapes, production ease, proteinaceous composition, and our ability to independently functionalize the interior and exterior interfaces. Here a VLP, derived from bacteriophage P22, is used as a building block for the fabrication of a protein macromolecular framework (PMF), a tightly linked 3D network of functional protein cages that exhibit long-range order and catalytic activity. Assembly of PMFs was electrostatically templated, using amine-terminated dendrimers, then locked into place with a ditopic cementing protein that binds to P22. Long-range order is preserved on removal of the dendrimer, leaving a framework material composed completely of protein. Encapsulation of β-glucosidase enzymes inside of P22 VLPs results in formation of stable, condensed-phase materials with high local concentration of enzymes generating catalytically active PMFs.

Application of banana peels nanosorbent for the removal of radioactive minerals from real mine water.

PubMed

Oyewo, Opeyemi A; Onyango, Maurice S; Wolkersdorfer, Christian

2016-11-01

Transformation of agricultural waste such as banana peels into a valuable sorbent material has been proven effective and efficient in wastewater treatment. Further, transformation into nanosorbent to enhance the removal capacity of actinides (uranium and thorium) from synthetic and real mine water is extensively investigated in this study. The nanosorbent samples before and after adsorption were characterised by X-ray diffraction (XRD), Fourier transform infra-red (FTIR), zetasizer nanoseries and scanning electron microscopy (SEM) while the amount of radioactive substances adsorbed was determined by inductively coupled plasma optical emission spectroscopy. Results revealed that there was a crystallite size and particle size reduction from 108 to 12 nm and <65,000 nm to <25 nm respectively as a function of milling time. Furthermore, appearance and disappearance of nanofibers via milling was noticed during structural analysis. The functional groups responsible for the banana peels capability to coordinate and remove metal ions were identified at absorption bands of 1730 cm -1 (carboxylic groups) and 889 cm -1 (amine groups) via FTIR analysis. Equilibrium isotherm results demonstrated that the adsorption process was endothermic for both uranium and thorium. The Langmuir maximum adsorption capacity was 27.1 mg g -1 , 34.13 mg g -1 for uranium and 45.5 mg g -1 , 10.10 mg g -1 for thorium in synthetic and real mine water, respectively. The results obtained indicate that nanostructured banana peels is a potential adsorbent for the removal of radioactive substances from aqueous solution and also from real mine water. However, the choice of this sorbent material for any application depends on the composition of the effluent to be treated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of the biological H2S removal characteristics among four inorganic packing materials.

PubMed

Hirai, M; Kamamoto, M; Yani, M; Shoda, M

2001-01-01

Four inorganic packing materials were evaluated in terms of their availability as packing materials of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological H2S removal characteristics and some physical properties. Among porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calcinated soil (D), the superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of H2S per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately equal to C > D approximately equal to B, which is correlated with the maximum water content, porosity, and mean pore diameter.

Comparison of nickel oxide and palladium nanoparticle loaded on activated carbon for efficient removal of methylene blue: kinetic and isotherm studies of removal process.

PubMed

Arabzadeh, S; Ghaedi, M; Ansari, A; Taghizadeh, F; Rajabi, M

2015-02-01

Palladium nanoparticles (Pd-NPs) and nickel oxide nanoparticles (NiO-NPs) were synthesized and loaded on activated carbon (AC). This novel material successfully used for the removal of methylene blue (MB) dye from aqueous medium. Full characterization of both material using X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Brunauer-Emmet-Teller analyses for Pd-NP show their high surface area (>1340 m(2)/g) and low pore size (<20 Å) and average particle size lower than 45 Å and for NiO-NP show their high surface area (>1316.1554 m(2)/g) and low pore size (<20 Å) and average particle size lower than 46 Å in addition to high reactive atom and presence of various functional groups. These unique properties make them possible for efficient removal of MB. In batch experimental set-up, optimum conditions for maximum removal of MB by both adsorbents were attained following searching effect of variables such as central composite design. The Langmuir isotherm was found to be highly recommended for fitting the experimental equilibrium data. The kinetic of adsorption of MB on both adsorbents strongly can be fitted by a combination of pseudo-second order and intraparticle diffusion pathway. The experimental result achieved in this article shows the superiority of Pd-NP-AC for MB removal than NiO-NP-AC, so the maximum adsorption capacities of Pd-NP-AC and NiO-NP-AC were 555.5 mg/g and 588.2 mg/g, respectively. © The Author(s) 2015.

Composition and method for removing photoresist materials from electronic components

DOEpatents

Davenhall, Leisa B [Santa Fe, NM; Rubin, James B [Los Alamos, NM; Taylor, Craig M. V. [Jemez Springs, NM

2008-06-03

Composition and method for removing photoresist materials from electronic components. The composition is a mixture of at least one dense phase fluid and at least one dense phase fluid modifier. The method includes exposing a substrate to at least one pulse of the composition in a supercritical state to remove photoresist materials from the substrate.

Composition and method for removing photoresist materials from electronic components

DOEpatents

Davenhall, Leisa B.; Rubin, James B.; Taylor, Craig M.

2005-01-25

Composition and method for removing photoresist materials from electronic components. The composition is a mixture of at least one dense phase fluid and at least one dense phase fluid modifier. The method includes exposing a substrate to at least one pulse of the composition in a supercritical state to remove photoresist materials from the substrate.

Optimization of outgassing bake-out temperatures and duration of space systems

NASA Technical Reports Server (NTRS)

Scialdone, J. J.

1986-01-01

Satellite components, e.g., solar panels, were subjected to bake-out tests to model outgassing characteristics and to identify methods for minimizing the bake-out time. Bake-out removes gases and particulates that are trapped at the surfaces of components during manufacture, storage, transit and handling. The tests covered temperatures from 45-85 C for up to 200 hr. Measurements of the mass loss rates were used to model the process as a function of the temperature, time and mass. Data sampling with a quartz crystal microbalance was found to be an effective means for ascertaining the mass loss rate and the activation energy of the release. The tests showed that the duration of the bake-out depends on the amount of material which must be removed and the type of outgassing which occurs. Materials which are resistant to high temperatures can be baked at the highest feasible temperatures to accelerate the outgassing process.

'Gate effect' in templated polyacrylamide membranes influences the electrotransport of proteins and finds applications in proteome analysis.

PubMed

Bossi, Alessandra; Andreoli, Matteo; Bonini, Francesca; Piletsky, Sergey

2007-09-01

Templating is an effective way for the structural modifications of a material and hence for altering its functional properties. Here protein imprinting was exploited to alter polymeric polyacrylamide (PAA) membranes. The sieving properties and selection abilities of the material formed were evaluated by studying the electrically driven transport of various proteins across templated PAA membranes. The sieving properties correlated with the templating process and depended on the quantity of template used during the polymerisation. For 1 mg/mL protein-templated membranes a 'gate effect' was shown, which induced a preferential migration of the template and of similar-size proteins. Such template preferential electrotransport was exploited for the selective removal of certain proteins in biological fluids prior to proteome analysis (depletion of albumin from human serum); the efficiency of the removal was demonstrated by analysing the serum proteome by two-dimensional electrophoresis experiments.

Simplified Prosthetic Rehabilitation of a Patient after Oral Cancer Removal

PubMed Central

Džakula, Nikola; Vojvodić, Denis

2016-01-01

The treatment of patients with oral cancer is complex: a multidisciplinary approach needs to be taken and maxillofacial and oral surgeons, an oncologist, a prosthodontist should be included, and a psychologist is often needed. This case report describes the prosthetic rehabilitation of a patient after surgical removal of oral cancer with obturator prosthesis. Resection cavity was located in central part of the hard palate and the condition belonged to Aramany class 3 maxillary defects. The two-step impression technique of denture bearing area was used and the resection of cavity was performed. A primary impression-the impression of denture bearing area was made using irreversible hydrocolloid material, while the second impression – the impression of resection cavity was made using condensation silicone material and obturator prosthesis framework. The obturator prosthesis replaced lost teeth, improved oral function and esthetics at minimal costs. PMID:27847400

Long-term performance of passive materials for removal of ozone from indoor air.

PubMed

Cros, C J; Morrison, G C; Siegel, J A; Corsi, R L

2012-02-01

The health effects associated with exposure to ozone range from respiratory irritation to increased mortality. In this paper, we explore the use of three green building materials and an activated carbon (AC) mat that remove ozone from indoor air. We studied the effects of long-term exposure of these materials to real environments on ozone removal capability and pre- and post-ozonation emissions. A field study was completed over a 6-month period, and laboratory testing was intermittently conducted on material samples retrieved from the field. The results show sustained ozone removal for all materials except recycled carpet, with greatest ozone deposition velocity for AC mat (2.5-3.8 m/h) and perlite-based ceiling tile (2.2-3.2 m/h). Carbonyl emission rates were low for AC across all field sites. Painted gypsum wallboard and perlite-based ceiling tile had similar overall emission rates over the 6-month period, while carpet had large initial emission rates of undesirable by-products that decayed rapidly but remained high compared with other materials. This study confirms that AC mats and perlite-based ceiling tile are viable surfaces for inclusion in buildings to remove ozone without generating undesirable by-products. PRACTICAL IMPLICATIONS The use of passive removal materials for ozone control could decrease the need for, or even render unnecessary, active but energy consuming control solutions. In buildings where ozone should be controlled (high outdoor ozone concentrations, sensitive populations), materials specifically designed or selected for removing ozone could be implemented, as long as ozone removal is not associated with large emissions of harmful by-products. We find that activated carbon mats and perlite-based ceiling tiles can provide substantial, long-lasting, ozone control. © 2011 John Wiley & Sons A/S.

Process Parameter Effects on Material Removal in Magnetorheological Finishing of Borosilicate Glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao, C.; Lambroopulos, J.C.; Jacobs, S.D.

2010-04-14

We investigate the effects of processing parameters on material removal for borosilicate glass. Data are collected on a magnetorheological finishing (MRF) spot taking machine (STM) with a standard aqueous magnetorheological (MR) fluid. Normal and shear forces are measured simultaneously, in situ, with a dynamic dual load cell. Shear stress is found to be independent of nanodiamond concentration, penetration depth, magnetic field strength, and the relative velocity between the part and the rotating MR fluid ribbon. Shear stress, determined primarily by the material mechanical properties, dominates removal in MRF. The addition of nanodiamond abrasives greatly enhances the material removal efficiency, withmore » the removal rate saturating at a high abrasive concentration. The volumetric removal rate (VRR) increases with penetration depth but is insensitive to magnetic field strength. The VRR is strongly correlated with the relative velocity between the ribbon and the part, as expected by the Preston equation. A modified removal rate model for MRF offers a better estimation of MRF removal capability by including nanodiamond concentration and penetration depth.« less

The chemo-mechanical effect of cutting fluid on material removal in diamond scribing of silicon

NASA Astrophysics Data System (ADS)

Kumar, Arkadeep; Melkote, Shreyes N.

2017-07-01

The mechanical integrity of silicon wafers cut by diamond wire sawing depends on the damage (e.g., micro-cracks) caused by the cutting process. The damage type and extent depends on the material removal mode, i.e., ductile or brittle. This paper investigates the effect of cutting fluid on the mode of material removal in diamond scribing of single crystal silicon, which simulates the material removal process in diamond wire sawing of silicon wafers. We conducted scribing experiments with a diamond tipped indenter in the absence (dry) and in the presence of a water-based cutting fluid. We found that the cutting mode is more ductile when scribing in the presence of cutting fluid compared to dry scribing. We explain the experimental observations by the chemo-mechanical effect of the cutting fluid on silicon, which lowers its hardness and promotes ductile mode material removal.

Organically functionalized mesoporous SBA-15 as sorbents for removal of selected pharmaceuticals from water.

PubMed

Bui, Tung Xuan; Kang, Seo-Young; Lee, Sang-Hyup; Choi, Heechul

2011-10-15

Mesoporous silica SBA-15 and its postfunctionalized counterparts with hydroxymethyl (HM-SBA-15), aminopropyl (AP-SBA-15), and trimethylsilyl (TMS-SBA-15) were prepared and characterized by powder X-ray diffraction, N(2) adsorption-desorption measurement, Fourier-transform infrared spectroscopy, and elemental analysis. The removal of a mixture of 12 selected pharmaceuticals was investigated by batch adsorption experiments onto SBA-15 and the grafted materials. SBA-15 showed to have moderate adsorption affinity with amino-containing (atenolol, trimethoprim) and hydrophobic pharmaceuticals, but it displayed minimal adsorption affinity toward hydrophilic compounds. HM-SBA-15 was analogous with SBA-15 in terms of the adsorption efficiency toward all pharmaceuticals. AP-SBA-15 exhibited an increase in the adsorption of two acidic compounds (clofibric acid, diclofenac) but a decrease in the adsorption of estrone and the two amino-containing compounds. Among the grafted materials, TMS-SBA-15 had the highest adsorption affinity toward most pharmaceuticals. Moreover, the adsorption of nine pharmaceuticals to TMS-SBA-15 was significantly higher than that to SBA-15; seven of which showed the removal percentages from 70.6% to 98.9% onto TMS-SBA-15. The number of pharmaceuticals showing high adsorption efficiency onto TMS-SBA-15 did not alter significantly as the pH changed in the range of 5.5-7.6. The results suggest that TMS-SBA-15 is a promising material for the removal of pharmaceuticals from aqueous phase, especially for the treatment of wastewater from drug manufacturers. Copyright © 2011 Elsevier B.V. All rights reserved.

Theory of adsorption in a polydisperse templated porous material: Hard sphere systems

NASA Astrophysics Data System (ADS)

RŻysko, Wojciech; Sokołowski, Stefan; Pizio, Orest

2002-03-01

A theoretical description of adsorption in a templated porous material, formed by an equilibrium quench of a polydisperse fluid composed of matrix and template particles and subsequent removal of the template particles is presented. The approach is based on the solution of the replica Ornstein-Zernike equations with Percus-Yevick and hypernetted chain closures. The method of solution uses expansions of size-dependent correlation functions into Fourier series, as described by Lado [J. Chem. Phys. 108, 6441 (1998)]. Specific calculations have been carried out for model systems, composed of hard spheres.

Evaluation and mechanism of ammonia nitrogen removal using sediments from a malodorous river

PubMed Central

Chen, Xing; Jiang, Xia

2018-01-01

Malodorous rivers are among the major environmental problems of cities in developing countries. In addition to the unpleasant smell, the sediments of such rivers can act as a sink for pollutants. The excessive amount of ammonia nitrogen (NH3−N) in rivers is the main factor that causes the malodour. Therefore, a suitable method is necessary for sediment disposition and NH3−N removal in malodorous rivers. The sediment in a malodorous river (PS) in Beijing, China was selected and modified via calcination (PS-D), Na+ doping (PS-Na) and calcination–Na+ doping (PS-DNa). The NH3−N removal efficiency using the four sediment materials was evaluated, and results indicated that the NH3−N removal efficiency using the modified sediment materials could reach over 60%. PS-DNa achieved the highest NH3−N removal efficiency (90.04%). The kinetics study showed that the pseudo-second-order model could effectively describe the sorption kinetics and that the exterior activated site had the main function of P sorption. The results of the sorption isotherms indicated that the maximum sorption capacities of PS-Na, PS-D and PS-DNa were 0.343, 0.831 and 1.113 mg g−1, respectively, and a high temperature was favourable to sorption. The calculated thermodynamic parameters suggested that sorption was a feasible or spontaneous (ΔG < 0), entropy-driven (ΔS > 0), and endothermic (ΔH > 0) reaction. PMID:29657816

Functional polyaniline/multiwalled carbon nanotube composite as an efficient adsorbent material for removing pharmaceuticals from aqueous media.

PubMed

Dutra, Flávia Viana Avelar; Pires, Bruna Carneiro; Nascimento, Tienne Aparecida; Borges, Keyller Bastos

2018-09-01

The composite polyaniline/multiwalled carbon nanotube (PAni/MWCNT, 1:0.1 w/w) was developed with the intention of binding the adsorbent properties of two materials and using it to adsorb pharmaceuticals from aqueous media. PAni/MWCNT was characterized by scanning electron microscopy, thermogravimetry, infrared spectroscopy, pH at the point of zero charge, and the effect on the surface wettability of the material. As proof of concept, adsorption studies were carried out using meloxicam (MLX) as the pharmaceutical and it was evaluated as a function of pH, temperature, ionic strength, contact time and variation in concentration. Kinetics and isothermal models were applied to evaluate the mechanism of the adsorption process. The best MLX adsorption result was at pH 2 with 6 min of contact with PAni/MWCNT. The kinetics models that fitted the experimental data were pseudo-second order and Elovich and the kinetics model was the dual-site Langmuir-Freundlich. Both models suggest that the adsorption occurs by the chemical nature of the surface and in the pores of the energetically heterogeneous composite. The PAni/MWCNT presented an adsorption capacity of 221.2 mg g -1 , a very good value when compared with the literature and can be used to remove pharmaceuticals from aqueous environments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biomaterials for craniofacial reconstruction

PubMed Central

Neumann, Andreas; Kevenhoerster, Kevin

2011-01-01

Biomaterials for reconstruction of bony defects of the skull comprise of osteosynthetic materials applied after osteotomies or traumatic fractures and materials to fill bony defects which result from malformation, trauma or tumor resections. Other applications concern functional augmentations for dental implants or aesthetic augmentations in the facial region. For ostheosynthesis, mini- and microplates made from titanium alloys provide major advantages concerning biocompatibility, stability and individual fitting to the implant bed. The necessity of removing asymptomatic plates and screws after fracture healing is still a controversial issue. Risks and costs of secondary surgery for removal face a low rate of complications (due to corrosion products) when the material remains in situ. Resorbable osteosynthesis systems have similar mechanical stability and are especially useful in the growing skull. The huge variety of biomaterials for the reconstruction of bony defects makes it difficult to decide which material is adequate for which indication and for which site. The optimal biomaterial that meets every requirement (e.g. biocompatibility, stability, intraoperative fitting, product safety, low costs etc.) does not exist. The different material types are (autogenic) bone and many alloplastics such as metals (mainly titanium), ceramics, plastics and composites. Future developments aim to improve physical and biological properties, especially regarding surface interactions. To date, tissue engineered bone is far from routine clinical application. PMID:22073101

Space environmental effects on silvered Teflon thermal control surfaces

NASA Technical Reports Server (NTRS)

Hemminger, C. S.; Stuckey, W. K.; Uht, J. C.

1991-01-01

Cumulative space environment effects on Ag/fluorinated ethylene propylene (FEP) were a function of exposure orientation. Samples from nineteen silvered Teflon (Ag/FEP) thermal control surfaces recovered from the Long Duration Exposure Facility (LDEF) were analyzed to determine changes in this material as a function of position on the spacecraft. Although solar absorptance and infrared emittance of measured thermal blanket specimens are relatively unchanged from control specimen values, significant changes in surface morphology, composition and chemistry were observed. Researchers hypothesize that the FEP surfaces on LDEF were degraded by ultraviolet radiation exposure at all orientations, but that the damaged material had been removed by erosion from the blankets exposed to atomic oxygen flux and that contamination is masking the damage on trays flanking the trailing edge.

Methods and apparatus for removal and control of material in laser drilling of a borehole

DOEpatents

Rinzler, Charles C; Zediker, Mark S; Faircloth, Brian O; Moxley, Joel F

2014-01-28

The removal of material from the path of a high power laser beam during down hole laser operations including drilling of a borehole and removal of displaced laser effected borehole material from the borehole during laser operations. In particular, paths, dynamics and parameters of fluid flows for use in conjunction with a laser bottom hole assembly.

Methods and apparatus for removal and control of material in laser drilling of a borehole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rinzler, Charles C.; Zediker, Mark S.; Faircloth, Brian O.

2016-12-06

The removal of material from the path of a high power laser beam during down hole laser operations including drilling of a borehole and removal of displaced laser effected borehole material from the borehole during laser operations. In particular, paths, dynamics and parameters of fluid flows for use in conjunction with a laser bottom hole assembly.

Performance of Silica Gel in the Role of Residual Air Drying

NASA Technical Reports Server (NTRS)

Jan, Darrell L.; Hogan, John A.; Koss, Brian; Palmer, Gary H.; Richardson, Justine; Linggi, Paul

2014-01-01

Removal of carbon dioxide (CO2) is a necessary step in air revitalization and is often accomplished with sorbent materials. Since moisture competes with CO2 in sorbent materials, it is necessary to remove the water first. This is typically accomplished in two stages: bulk removal and residual drying. Silica gel is used as the bulk drying material in the Carbon Dioxide Removal Assembly (CDRA) in operation on ISS. There has been some speculation that silica gel may also be capable of serving as the residual drying material. This paper will describe test apparatus and procedures for determining the performance of silica gel in residual air drying.

The Bilinear Product Model of Hysteresis Phenomena

NASA Astrophysics Data System (ADS)

Kádár, György

1989-01-01

In ferromagnetic materials non-reversible magnetization processes are represented by rather complex hysteresis curves. The phenomenological description of such curves needs the use of multi-valued, yet unambiguous, deterministic functions. The history dependent calculation of consecutive Everett-integrals of the two-variable Preisach-function can account for the main features of hysteresis curves in uniaxial magnetic materials. The traditional Preisach model has recently been modified on the basis of population dynamics considerations, removing the non-real congruency property of the model. The Preisach-function was proposed to be a product of two factors of distinct physical significance: a magnetization dependent function taking into account the overall magnetization state of the body and a bilinear form of a single variable, magnetic field dependent, switching probability function. The most important statement of the bilinear product model is, that the switching process of individual particles is to be separated from the book-keeping procedure of their states. This empirical model of hysteresis can easily be extended to other irreversible physical processes, such as first order phase transitions.

Overview on the Surface Functionalization Mechanism and Determination of Surface Functional Groups of Plasma Treated Carbon Nanotubes.

PubMed

Saka, Cafer

2018-01-02

The use of carbon materials for many applications is due to the unique diversity of structures and properties ranging from chemical bonds between the carbon atoms of the materials to nanostructures, crystallite alignment, and microstructures. Carbon nanotubes and other nanoscale carbonaceous materials draw much attention due to their physical and chemical properties, such as high strength, high resistance to corrosion, electrical and thermal conductivity, stability and a qualified adsorbent. Carbon-based nanomaterials, which have a relatively large specific area and layered structure, can be used as an adsorbent for efficient removal of organic and inorganic contaminants. However, one of the biggest obstacles to the development of carbon-based nanomaterials adsorbents is insolubility and the lack of functional groups on the surface. There are several approaches to introduce functional groups on carbon nanotubes. One of these approaches, plasma applications, now has an important place in the creation of surface functional groups as a flexible, fast, and environmentally friendly method. This review focuses on recent information concerning the surface functionalization and modification of plasma treated carbon nanotube. This review considers the surface properties, advantages, and disadvantages of plasma-applied carbon nanotubes. It also examines the reaction mechanisms involved in the functional groups on the surface.

Fine platinum nanoparticles supported on a porous ceramic membrane as efficient catalysts for the removal of benzene.

PubMed

Liu, Hui; Li, Chengyin; Ren, Xiaoyong; Liu, Kaiqi; Yang, Jun

2017-11-29

It would be desirable to remove volatile organic compounds (VOCs) while we eliminate the dusts using silicon carbide (SiC)-based porous ceramics from the hot gases. Aiming at functionalizing SiC-based porous ceramics with catalytic capability, we herein report a facile strategy to integrate high efficient catalysts into the porous SiC substrates for the VOC removal. We demonstrate an aqueous salt method for uniformly distributing fine platinum (Pt) particles on the alumina (Al 2 O 3 ) layers, which are pre-coated on the SiC substrates as supports for VOC catalysts. We confirm that at a Pt mass loading as low as 0.176% and a weight hourly space velocity of 6000 mL g -1 h -1 , the as-prepared Pt/SiC@Al 2 O 3 catalysts can convert 90% benzene at a temperature of ca. 215 °C. The results suggest a promising way to design ceramics-based bi-functional materials for simultaneously eliminating dusts and harmful VOCs from various hot gases.

Investigation of “benign” ionic content in epoxy that induces microelectronic device failure

Treesearch

Gregory T. Schueneman; Jeffery Kingsbury; Edmund Klinkerch

2011-01-01

Microelectronics and the devices dependent upon them have the extremely challenging requirements of becoming more capable and less expensive every year. This drives the industry to pack more functions into an ever smaller footprint until the next technological revolution. Adding to this situation is the removal of lead from the bill of materials followed closely by...

Collagen based magnetic nanocomposites for oil removal applications

PubMed Central

Thanikaivelan, Palanisamy; Narayanan, Narayanan T.; Pradhan, Bhabendra K.; Ajayan, Pulickel M.

2012-01-01

A stable magnetic nanocomposite of collagen and superparamagnetic iron oxide nanoparticles (SPIONs) is prepared by a simple process utilizing protein wastes from leather industry. Molecular interaction between helical collagen fibers and spherical SPIONs is proven through calorimetric, microscopic and spectroscopic techniques. This nanocomposite exhibited selective oil absorption and magnetic tracking ability, allowing it to be used in oil removal applications. The environmental sustainability of the oil adsorbed nanobiocomposite is also demonstrated here through its conversion into a bi-functional graphitic nanocarbon material via heat treatment. The approach highlights new avenues for converting bio-wastes into useful nanomaterials in scalable and inexpensive ways. PMID:22355744

Coating carbon nanotubes with humic acid using an eco-friendly mechanochemical method: Application for Cu(II) ions removal from water and aquatic ecotoxicity.

PubMed

Côa, Francine; Strauss, Mathias; Clemente, Zaira; Rodrigues Neto, Laís L; Lopes, Josias R; Alencar, Rafael S; Souza Filho, Antônio G; Alves, Oswaldo L; Castro, Vera Lúcia S S; Barbieri, Edison; Martinez, Diego Stéfani T

2017-12-31

In this work, industrial grade multi-walled carbon nanotubes (MWCNT) were coated with humic acid (HA) for the first time by means of a milling process, which can be considered an eco-friendly mechanochemical method to prepare materials and composites. The HA-MWCNT hybrid material was characterized by atomic force microscopy (AFM), scanning electron microscopies (SEM and STEM), X-ray photoelectron spectroscopy (XPS), termogravimetric analysis (TGA), and Raman spectroscopy. STEM and AFM images demonstrated that the MWCNTs were efficiently coated by the humic acid, thus leading to an increase of 20% in the oxygen content at the nanotube surface as observed by the XPS data. After the milling process, the carbon nanotubes were shortened as unveiled by SEM images and the values of ID/IG intensity ratio increased due to shortening of the nanotubes and increasing in the number defects at the graphitic structure of carbon nanotubes walls. The analysis of TGA data showed that the quantity of the organic matter of HA on the nanotube surface was 25%. The HA coating was responsible to favor the dispersion of MWCNTs in ultrapure water (i.e. -42mV, zeta-potential value) and to improve their capacity for copper removal. HA-MWCNTs hybrid material adsorbed 2.5 times more Cu(II) ions than oxidized MWCNTs with HNO 3 , thus evidencing that it is a very efficient adsorbent material for removing copper ions from reconstituted water. The HA-MWCNTs hybrid material did not show acute ecotoxicity to the tested aquatic model organisms (Hydra attenuata, Daphnia magna, and Danio rerio embryos) up to the highest concentration evaluated (10mgL -1 ). The results allowed concluding that the mechanochemical method is effective to coat carbon nanotubes with humic acid, thus generating a functional hybrid material with low aquatic toxicity and great potential to be applied in environmental nanotechnologies such as the removal of heavy metal ions from water. Copyright © 2017 Elsevier B.V. All rights reserved.

Improved force prediction model for grinding Zerodur based on the comprehensive material removal mechanism.

PubMed

Sun, Guoyan; Zhao, Lingling; Zhao, Qingliang; Gao, Limin

2018-05-10

There have been few investigations dealing with the force model on grinding brittle materials. However, the dynamic material removal mechanisms have not yet been sufficiently explicated through the grain-workpiece interaction statuses while considering the brittle material characteristics. This paper proposes an improved grinding force model for Zerodur, which contains ductile removal force, brittle removal force, and frictional force, corresponding to the ductile and brittle material removal phases, as well as the friction process, respectively. The critical uncut chip thickness a gc of brittle-ductile transition and the maximum uncut chip thickness a gmax of a single abrasive grain are calculated to identify the specified material removal mode, while the comparative result between a gmax and a gc can be applied to determine the selection of effective grinding force components. Subsequently, indentation fracture tests are carried out to acquire accurate material mechanical properties of Zerodur in establishing the brittle removal force model. Then, the experiments were conducted to derive the coefficients in the grinding force prediction model. Simulated through this model, correlations between the grinding force and grinding parameters can be predicted. Finally, three groups of grinding experiments are carried out to validate the mathematical grinding force model. The experimental results indicate that the improved model is capable of predicting the realistic grinding force accurately with the relative mean errors of 6.04% to the normal grinding force and 7.22% to the tangential grinding force, respectively.

Adsorptive removal of antibiotics from aqueous solution using carbon materials.

PubMed

Yu, Fei; Li, Yong; Han, Sheng; Ma, Jie

2016-06-01

Antibiotics, an important type of environmental contamination, have attracted many researchers to the study of their removal from aqueous solutions. Adsorption technology is a fast, efficient, and economical physicochemical method that is extensively used in wastewater treatment. From original activated carbon and carbon nanotubes to the latest graphene-based materials, carbon-based materials have been widely used as highly effective adsorbents for contaminant removal from aqueous solution because of their large specific surface area, high porosity, and high reaction activity. In this article, adsorption removal methods for four major types of antibiotic (tetracyclines, sulfonamides, macrolides, and quinolones) are reviewed. We also provide an overview of the application development of carbon materials as adsorbents for antibiotic removal from aqueous solution. The most promising works are discussed, and the main challenges in preparing high-performance adsorbents and the development tendency of adsorbents are also analyzed. This work provides theoretical guidance for subsequent research in the design and modification of carbon materials for applications in the adsorption removal of antibiotics from aqueous solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Subsurface Damage in Polishing Process of Silicon Carbide Ceramic

PubMed Central

Gu, Yan; Zhu, Wenhui; Lin, Jieqiong; Lu, Mingming; Kang, Mingshuo

2018-01-01

Subsurface damage (SSD) in the polishing process of silicon carbide (SiC) ceramic presents one of the most significant challenges for practical applications. In this study, the theoretical models of SSD depth are established on the basis of the material removal mechanism and indentation fracture mechanics in the SiC ceramic polishing process. In addition, the three-dimensional (3D) models of single grit polishing are also developed by using the finite element simulation; thereby, the dynamic effects of different process parameters on SSD depth are analyzed. The results demonstrate that the material removal was mainly in brittle mode when the cutting depth was larger than the critical depth of the brittle material. The SSD depth increased as the polishing depth and abrasive grain size increased, and decreased with respect to the increase in polishing speed. The experimental results suggested a good agreement with the theoretical simulation results in terms of SSD depth as a function of polishing depth, spindle speed, and abrasive grain size. This study provides a mechanistic insight into the dependence of SSD on key operational parameters in the polishing process of SiC ceramic. PMID:29584694

Grinding, Machining Morphological Studies on C/SiC Composites

NASA Astrophysics Data System (ADS)

Xiao, Chun-fang; Han, Bing

2018-05-01

C/SiC composite is a typical material difficult to machine. It is hard and brittle. In machining, the cutting force is large, the material removal rate is low, the edge is prone to collapse, and the tool wear is serious. In this paper, the grinding of C/Si composites material along the direction of fiber distribution is studied respectively. The surface microstructure and mechanical properties of C/SiC composites processed by ultrasonic machining were evaluated. The change of surface quality with the change of processing parameters has also been studied. By comparing the performances of conventional grinding and ultrasonic grinding, the surface roughness and functional characteristics of the material can be improved by optimizing the processing parameters.

Compositions and methods for removal of toxic metals and radionuclides

NASA Technical Reports Server (NTRS)

McKay, David S. (Inventor); Cuero, Raul G. (Inventor)

2007-01-01

The present invention relates to compositions and methods for the removal of toxic metals or radionuclides from source materials. Toxic metals may be removed from source materials using a clay, such as attapulgite or highly cationic bentonite, and chitin or chitosan. Toxic metals may also be removed using volcanic ash alone or in combination with chitin or chitosan. Radionuclides may be removed using volcanic ash alone or in combination with chitin or chitosan.

Open circuit versus closed circuit enrichment of anodic biofilms in MFC: effect on performance and anodic communities.

PubMed

Larrosa-Guerrero, Amor; Scott, Keith; Katuri, Krishna P; Godinez, Carlos; Head, Ian M; Curtis, Thomas

2010-08-01

The influence of various carbon anodes; graphite, sponge, paper, cloth, felt, fiber, foam and reticulated vitreous carbon (RVC); on microbial fuel cell (MFC) performance is reported. The feed was brewery wastewater diluted in domestic wastewater. Biofilms were grown at open circuit or under an external load. Microbial diversity was analysed as a function of current and anode material. The bacterial community formed at open circuit was influenced by the anode material. However at closed circuit its role in determining the bacterial consortia formed was less important than the passage of current. The rate and extent of organic matter removal were similar for all materials: over 95% under closed circuit. The biofilm in MFCs working at open circuit and in the control reactors, increased COD removal by up to a factor of nine compared with that for baseline reactors. The average voltage output was 0.6 V at closed circuit, with an external resistor of 300 kOmega and 0.75 V at open circuit for all materials except RVC. The poor performance of this material might be related to the surface area available and concentration polarizations caused by the morphology of the material and the structure of the biofilm. Peak power varied from 1.3 mW m(-2) for RVC to 568 mW m(-2) for graphite with biofilm grown at closed circuit.

A critical study on efficiency of different materials for fluoride removal from aqueous media

PubMed Central

2013-01-01

Fluoride is a persistent and non-biodegradable pollutant that accumulates in soil, plants, wildlife and in human beings. Therefore, knowledge of its removal, using best technique with optimum efficiency is needed. The present survey highlights on efficacy of different materials for the removal of fluoride from water. The most important results of extensive studies on various key factors (pH, agitation time, initial fluoride concentration, temperature, particle size, surface area, presence and nature of counter ions and solvent dose) fluctuate fluoride removal capacity of materials are reviewed. PMID:23497619

324 Building spent fuel segments pieces and fragments removal summary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

SMITH, C L

2003-01-09

As part of the 324 Building Deactivation Project, all Spent Nuclear Fuel (SNF) and Special Nuclear Material were removed. The removal entailed packaging the material into a GNS-12 cask and shipping it to the Central Waste Complex (CWC).

Self-cleaning of superhydrophobic surfaces by self-propelled jumping condensate

PubMed Central

Wisdom, Katrina M.; Qu, Xiaopeng; Liu, Fangjie; Watson, Gregory S.; Chen, Chuan-Hua

2013-01-01

The self-cleaning function of superhydrophobic surfaces is conventionally attributed to the removal of contaminating particles by impacting or rolling water droplets, which implies the action of external forces such as gravity. Here, we demonstrate a unique self-cleaning mechanism whereby the contaminated superhydrophobic surface is exposed to condensing water vapor, and the contaminants are autonomously removed by the self-propelled jumping motion of the resulting liquid condensate, which partially covers or fully encloses the contaminating particles. The jumping motion off the superhydrophobic surface is powered by the surface energy released upon coalescence of the condensed water phase around the contaminants. The jumping-condensate mechanism is shown to spontaneously clean superhydrophobic cicada wings, where the contaminating particles cannot be removed by gravity, wing vibration, or wind flow. Our findings offer insights for the development of self-cleaning materials. PMID:23630277

The effect of materials selection on metals reduction in propylene glycol methyl ether acetate, PGMEA

NASA Astrophysics Data System (ADS)

Entezarian, Majid; Geiger, Bob

2016-03-01

The trend in microelectronics fabrication is to produce nano-features measuring down to 10 nm and finer. The PPT levels of organic and inorganic contaminants in the photoresist, solvent and cleaning solutions are becoming a major processing variable affecting the process capability and defectivity. The photoresist usually contains gels, metals, and particulates that could interfere with the lithography process and cause microbridging defects. Nano filters of 5 nm polypropylene, 5 nm polyethylene, and 10 nm natural nylon were used to filter propylene glycol methyl ether acetate PGMEA containing 50 ppb of Na, Mg, Al, Ca, Cr, Mn, Fe, Cu, Zn, and Pb. All filters were effective in removing trivalent Al, Cr, and Fe metals indicating the mechanism for their removal as mechanical sieving. However, the nylon was also very effective in removing the divalent metals showing adsorptive properties. Furthermore, the metal removal of the nylon membrane was studied as a function of surface chemistry. Natural and charged 40 nm nylon membranes were tested and found that charged nylon is more effective for metal removal.

Sorbent Structural Testing on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

NASA Technical Reports Server (NTRS)

Watson, David; Knox, James C.; West, Phillip; Bush, Richard

2016-01-01

Long term space missions require carbon dioxide removal systems that can function with minimal downtime required for maintenance, low power consumption and maximum efficiency for CO2 removal. A major component of such a system are the sorbents used for the CO2 and desiccant beds. Sorbents must not only have adequate CO2 and H2O removal properties, but they must have the mechanical strength to prevent structural breakdown due to pressure and temperature changes during operation and regeneration, as well as resistance to breakdown due to moisture in the system from cabin air. As part of the studies used to select future CO2 sorbent materials, mechanical tests are performed on various zeolite sorbents to determine mechanical performance while dry and at various humidified states. Tests include single pellet crush, bulk crush and attrition tests. We have established a protocol for testing sorbents under dry and humid conditions, and previously tested the sorbents used on the International Space Station carbon dioxide removal assembly. This paper reports on the testing of a series of commercial sorbents considered as candidates for use on future exploration missions.

Removal of arsenic from water using nano adsorbents and challenges: A review.

PubMed

Lata, Sneh; Samadder, S R

2016-01-15

Many researchers have used nanoparticles as adsorbents to remove water pollutants including arsenic after modifying the properties of nanoparticles by improving reactivity, biocompatibility, stability, charge density, multi-functionalities, and dispersibility. For arsenic removal, nano adsorbents emerged as the potential alternatives to existing conventional technologies. The present study critically reviewed the past and current available information on the potential of nano adsorbents for arsenic removal from contaminated water and the challenges involved in that. The study discussed the separation and regeneration techniques of nano adsorbents and the performance thereof. The study evaluated the adsorption efficiency of the various nanoparticles based on size of nanoparticles, types of nano adsorbents, method of synthesis, separation and regeneration of the nano adsorbents. The study found that more studies are required on suitable holding materials for the nano adsorbents to improve the permeability and to make the technology applicable at the field condition. The study will help the readers to choose suitable nanomaterials and to take up further research required for arsenic removal using nano adsorbents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biosorbents for Removing Hazardous Metals and Metalloids †

PubMed Central

Inoue, Katsutoshi; Parajuli, Durga; Ghimire, Kedar Nath; Biswas, Biplob Kumar; Kawakita, Hidetaka; Oshima, Tatsuya; Ohto, Keisuke

2017-01-01

Biosorbents for remediating aquatic environmental media polluted with hazardous heavy metals and metalloids such as Pb(II), Cr(VI), Sb(III and V), and As(III and V) were prepared from lignin waste, orange and apple juice residues, seaweed and persimmon and grape wastes using simple and cheap methods. A lignophenol gel such as lignocatechol gel was prepared by immobilizing the catechol functional groups onto lignin from sawdust, while lignosulfonate gel was prepared directly from waste liquor generated during pulp production. These gels effectively removed Pb(II). Orange and apple juice residues, which are rich in pectic acid, were easily converted using alkali (e.g., calcium hydroxide) into biosorbents that effectively removed Pb(II). These materials also effectively removed Sb(III and V) and As(III and V) when these were preloaded with multi-valent metal ions such as Zr(IV) and Fe(III). Similar biosorbents were prepared from seaweed waste, which is rich in alginic acid. Other biosorbents, which effectively removed Cr(VI), were prepared by simply treating persimmon and grape wastes with concentrated sulfuric acid. PMID:28773217

Catalytic wet air oxidation of phenol with functionalized carbon materials as catalysts: reaction mechanism and pathway.

PubMed

Wang, Jianbing; Fu, Wantao; He, Xuwen; Yang, Shaoxia; Zhu, Wanpeng

2014-08-01

The development of highly active carbon material catalysts in catalytic wet air oxidation (CWAO) has attracted a great deal of attention. In this study different carbon material catalysts (multi-walled carbon nanotubes, carbon fibers and graphite) were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction, the removal of phenol was nearly 100% over the functionalized multi-walled carbon, while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals, which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions, a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First, maleic acid is transformed directly into malonic acid. Second, acetic acid is oxidized into an unknown intermediate, which is then oxidized into CO2 and H2O. Finally, formic acid and oxalic acid can mutually interconvert when conditions are favorable. Copyright © 2014. Published by Elsevier B.V.

Zirconia removable telescopic dentures retained on teeth or implants for maxilla rehabilitation. Three-year observation of three cases.

PubMed

Zafiropoulos, Gregory-George; Rebbe, Jochen; Thielen, Ulrich; Deli, Giorgio; Beaumont, Christian; Hoffmann, Oliver

2010-01-01

This report addresses maxillary restoration with removable telescopic crown-retained palatal free dentures. One patient with 7 natural teeth (PERIO), a second patient with 6 dental implants (IMPL), and a third patient with 2 natural teeth and 4 dental implants (IMPL-PERIO) were treated. Zirconia copings for natural teeth and individual zirconia implant abutments were fabricated in CAD/CAM and used as primary crowns. Electroformed gold copings were used as secondary telescopes. All maxilla supraconstructions were fabricated with zirconia and CAD/CAM. Patients were monitored during a 3-year period; all teeth and implants survived, and no biological or mechanical complications occurred. The peri-implant and periodontal conditions were healthy. While recognizing the limitations of this report, results showed that fabricating removable zirconia structures by means of CAD/CAM can yield highly functional and esthetic results. Galvanoforming technology is the preferable means of fabricating secondary crowns. The combination of these techniques and materials results in a prosthetic reconstruction of high quality, good fit, and biocompatibility. Long-term studies of large populations are necessary to investigate the clinical properties of the material utilized in this type of construction.

A novel route for the removal of bodily heavy metal lead (II)

NASA Astrophysics Data System (ADS)

Huang, Weirong; Zhang, Penghua; Xu, Hui; Chang, Shengli; He, Yongju; Wang, Fei; Liang, Gaowei

2015-09-01

The lead ion concentration in bile is considerably higher than in blood, and bile is released into the alimentary tract. Thiol-modified SBA-15 administered orally can combine with lead ions in the alimentary tract. In this paper, the in vitro lead absorption of bile was investigated. This thiol-modified SBA-15 material was used in pharmacodynamics studies on rabbits. The result that the lead content in faeces was notably higher indicates that thiol-modified SBA-15 can efficiently remove lead. The mechanism could include the following: thiol-modified SBA-15 material cuts off the heavy metal lead recirculation in the process of bile enterohepatic circulation by chelating the lead in the alimentary tract, causing a certain proportion of lead to be removed by the thiol mesoporous material, and the lead is subsequently egested out of the body in faeces. The results indicate that this material might be a potential non-injection material for the removal bodily heavy metal lead in the alimentary tract. This material may also be a useful means of lead removal, especially for non-acute sub-poisoning symptoms.

Water hyacinths and alligator weeds for removal of lead and mercury from polluted waters

NASA Technical Reports Server (NTRS)

Wolverton, B. C.; Mcdonald, R. C.

1975-01-01

Removal of lead and mercury by water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb. was investigated. Water hyacinths demonstrated the ability to remove 0.176 mg of lead and 0.150 mg of mercury per gram of dry plant material from distilled water and river water in a 24-hour period. One acre of water hyacinths is potentially capable of removing 105.6 grams of lead and 90.0 grams of mercury per day. Alligator weeds removed 0.101 mg of lead per gram of dry plant material in a 24-hour period. This same plant also demonstrated the ability to remove a minimum of 0.153 mg of mercury per gram of dry plant material in a six hour period.

Removal of natural hormones in dairy farm wastewater using reactive and sorptive materials.

PubMed

Cai, Kai; Phillips, Debra H; Elliott, Christopher T; Muller, Marc; Scippo, Marie-Louise; Connolly, Lisa

2013-09-01

The objective of this study was to examine the oestrogen and androgen hormone removal efficiency of reactive (Connelly zero-valent iron (ZVI), Gotthart Maier ZVI) and sorptive (AquaSorb 101 granular activated carbon (GAC) and OrganoLoc PM-100 organoclay (OC)) materials from HPLC grade water and constructed wetland system (CWS) treated dairy farm wastewater. Batch test studies were performed and hormone concentration analysis carried out using highly sensitive reporter gene assays (RGAs). The results showed that hormonal interaction with these materials is selective for individual classes of hormones. Connelly ZVI and AquaSorb 101 GAC were more efficient in removing testosterone (Te) than 17β-estradiol (E2) and showed faster removal rates of oestrogen and androgen than the other materials. Gotthart Maier ZVI was more efficient in removing E2 than Te. OrganoLoc PM-100 OC achieved the lowest final concentration of E2 equivalent (EEQ) and provided maximum removal of both oestrogens and androgens. Copyright © 2013 Elsevier B.V. All rights reserved.

Developing of a magnetite film of carboxymethyl cellulose grafted carboxymethyl polyvinyl alcohol (CMC-g-CMPVA) for copper removal.

PubMed

Dahlan, Nuraina Anisa; Veeramachineni, Anand Kumar; Langford, Steven James; Pushpamalar, Janarthanan

2017-10-01

Crosslinked carboxymethyl cellulose grafted carboxymethyl polyvinyl alcohol (CMC-g-CMPVA) was loaded with modified magnetite iron oxide (Fe 3 O 4 ) nanoparticles to synthesise a new and easily separable adsorbent for the removal of copper (II) ions from water. The novel adsorbents were characterised by the presence of the functional group, surface morphology, crystallinity and magnetic property. The equilibrium time from the adsorption studies was found to be less than 240min for both film and bead forms while the rate of Cu 2+ removal decreased as the initial Cu 2+ concentration increased. In addition, CMC-g-CMPVA film loaded with Fe 3 O 4 /SiO 2 nanoparticles was the best adsorbent with maximum adsorption capacity of 35.34mg/g and exhibited a reusable potential. The properties exhibited by the new heterogeneous material is a promising adsorbent for the removal and recovery of copper (II) from wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

An innovative attached-growth biological system for purification of pond water.

PubMed

Chang, Chia-Yuan; Chang, Jing-Song; Chen, Chien-Min; Chiemchaisri, Chart; Vigneswaran, Saravanamuthu

2010-03-01

This study applied the non-woven material from used diaper as the carrier for bio-film process to purify the recycled water from a landscape pond at the Tainan City Municipal Culture Center (TCMCC), Taiwan. An on-site system was installed and the experiment was accomplished through three stages in 192 days with different time periods of 70 days, 63 days, and 59 days, respectively. The results showed that the non-woven media is functional for SS removal. The average SS removal of stages 1, 2, and 3 were 91%, 96%, and 95%, respectively. The highest SCOD removal efficiency of 90% occurred at stage 3. A significant color improvement of the pond water was achieved through this non-woven bio-carrier treatment system. Whole system can be without any maintenance for 139 days. The result indicated that the non-woven medium system was with a great potential in treating and recycling the pond water with stable operation and satisfactory removal performance. 2009 Elsevier Ltd. All rights reserved.

Biosorption of Nickel from Industrial Wastewater using Zygnema sp.

NASA Astrophysics Data System (ADS)

Sivaprakash, Kanchana; Blessi T. L., Adlin; Madhavan, Jeyanthi

2015-12-01

Contamination of water sources with heavy metals is a very important pollution problem in the current scenario. Biosorption is an effective method for the removal of heavy metal ions from wastewaters. In this study, the removal of Nickel(II) ions from electroplating industrial wastewater using biosorbent prepared from fresh water algal biomass Zygnema was investigated under batch mode. The sorption efficiency of nickel on Zygnema sp. was evaluated as a function of time, pH and sorbent dosage. The Nickel(II) uptake was dependent on initial pH with pH 3 being the optimum value. For 100 mg/L initial Nickel(II) concentration, sorption equilibrium was attained at a contact time of 100 min. The sorbent dosage affected the biosorption efficiency and maximum removal of 76.4 % was obtained at a dosage of 7.5 g/L. From the performance studies, algal biosorbent Zygnema is found to be a valuable material for the removal of Nickel from industrial wastewater and a better substitute for the conventional adsorbents.

Material Behavior At The Extreme Cutting Edge In Bandsawing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarwar, Mohammed; Haider, Julfikar; Persson, Martin

2011-01-17

In recent years, bandsawing has been widely accepted as a favourite option for metal cutting off operations where the accuracy of cut, good surface finish, low kerf loss, long tool life and high material removal rate are required. Material removal by multipoint cutting tools such as bandsaw is a complex mechanism owing to the geometry of the bandsaw tooth (e.g., limited gullet size, tooth setting etc.) and the layer of material removed or undeformed chip thickness or depth of cut (5 {mu}m-50 {mu}m) being smaller than or equal to the cutting edge radius (5 {mu}m-15 {mu}m). This situation can leadmore » to inefficient material removal in bandsawing. Most of the research work are concentrated on the mechanics of material removal by single point cutting tool such as lathe tool. However, such efforts are very limited in multipoint cutting tools such as in bandsaw. This paper presents the fundamental understanding of the material behaviour at the extreme cutting edge of bandsaw tooth, which would help in designing and manufacturing of blades with higher cutting performance and life. ''High Speed Photography'' has been carried out to analyse the material removal process at the extreme cutting edge of bandsaw tooth. Geometric model of chip formation mechanisms based on the evidences found during ''High Speed Photography'' and ''Quick Stop'' process is presented. Wear modes and mechanism in bimetal and carbide tipped bandsaw teeth are also presented.« less

Computational designing and screening of solid materials for CO2capture

NASA Astrophysics Data System (ADS)

Duan, Yuhua

In this presentation, we will update our progress on computational designing and screening of solid materials for CO2 capture. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO2 sorbent candidates from the vast array of possible solid materials have been proposed and validated at NETL. The advantage of this method is that it identifies the thermodynamic properties of the CO2 capture reaction as a function of temperature and pressure without any experimental input beyond crystallographic structural information of the solid phases involved. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO2 adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO2 capture reactions by the solids of interest, we were able to identify only those solid materials for which lower capture energy costs are expected at the desired working conditions. In addition, we present a simulation scheme to increase and decrease the turnover temperature (Tt) of solid capturing CO2 reaction by mixing other solids. Our results also show that some solid sorbents can serve as bi-functional materials: CO2 sorbent and CO oxidation catalyst. Such dual functionality could be used for removing both CO and CO2 after water-gas-shift to obtain pure H2.

Adsorbent materials from paper industry waste materials and their use in Cu(II) removal from water.

PubMed

Méndez, A; Barriga, S; Fidalgo, J M; Gascó, G

2009-06-15

This paper deals with the removal of Cu(2+) from water using adsorbent materials prepared from paper industry waste materials (one de-inking paper sludge and other sludge from virgin pulp mill). Experimental results showed that de-inking paper sludge leads to mesoporous materials (V(mic)/V(T)=0.13 and 0.14), whereas the sludge from virgin pulp mill produces high microporous adsorbents (V(mic)/V(T)=0.39 and 0.41). Adsorbent materials were then used for Cu(2+) removal from water at acid pH. During water treatment, heavy metals lixiviation from adsorbent materials was not produced. However, important Ca and Mg leaching was observed. Final pH significantly increases after treatment of water with adsorbent materials probably due to their elevated CaCO(3) content. In general, highest Cu(2+) removal was obtained using adsorbent materials from de-inking paper sludge. This result could be due to their higher content in oxygenated surface groups, high average pore diameter, elevated superficial charge density, high CaCO(3) amount and high Ca and Mg exchange content.

In vitro evaluation of efficacy of different rotary instrument systems for gutta percha removal during root canal retreatment

PubMed Central

Joseph, Mercy; Malhotra, Amit; Rao, Murali; Sharma, Abhimanyu; Talwar, Sangeeta

2016-01-01

Background Complete removal of old filling material during root canal retreatment is fundamental for predictable cleaning and shaping of canal anatomy. Most of the retreatment methods tested in earlier studies have shown inability to achieve complete removal of root canal filling. Therefore the aim of this investigation was to assess the efficacy of three different rotary nickel titanium retreatment systems and Hedstrom files in removing filling material from root canals. Material and Methods Sixty extracted mandibular premolars were decoronated to leave 15 mm root. Specimen were hand instrumented and obturated using gutta percha and AH plus root canal sealer. After storage period of two weeks, roots were retreated with three (Protaper retreatment files, Mtwo retreatment files, NRT GPR) rotary retreatment instrument systems and Hedstroem files. Subsequently, samples were sectioned longitudinally and examined under stereomicroscope. Digital images were recorded and evaluated using Digital Image Analysing Software. The retreatment time was recorded for each tooth using a stopwatch. The area of canal and the residual filling material was recorded in mm2 and the percentage of remaining filling material on canal walls was calculated. Data was analysed using ANOVA test. Results Significantly less amount of residual filling material was present in protaper and Mtwo instrumented teeth (p < 0.05) compared to NRT GPR and Hedstrom files group. Protaper instruments also required lesser time during removal of filling material followed by Mtwo instruments, NRT GPR files and Hedstrom files. Conclusions None of the instruments were able to remove the filling material completely from root canal. Protaper universal retreatment system and Mtwo retreatment files were more efficient and faster compared to NRT GPR fles and Hedstrom files. Key words:Gutta-percha removal, nickel titanium, root canal retreatment, rotary instruments. PMID:27703601

Molecular Grafting of Fluorinated and Nonfluorinated Alkylsiloxanes on Various Ceramic Membrane Surfaces for the Removal of Volatile Organic Compounds Applying Vacuum Membrane Distillation.

PubMed

Kujawa, Joanna; Al-Gharabli, Samer; Kujawski, Wojciech; Knozowska, Katarzyna

2017-02-22

Four main tasks were presented: (i) ceramic membrane functionalization (TiO 2 5 kDa and 300 kDa), (ii) extended material characterization (physicochemistry and tribology) of pristine and modified ceramic samples, (iii) evaluation of chemical and mechanical stability, and finally (iv) assessment of membrane efficiency in vacuum membrane distillation applied for volatile organic compounds (VOCs) removal from water. Highly efficient molecular grafting with four types of perfluoroalkylsilanes and one nonfluorinated agent was developed. Materials with controllable tribological and physicochemical properties were achieved. The most meaningful finding is associated with the applicability of fluorinated and nonfluorinated grafting agents. The results of contact angle, hysteresis of contact angle, sliding angle, and critical surface tension as well as Young's modulus, nanohardness, and adhesion force for grafting by these two modifiers are comparable. This provides insight into the potential applicability of environmental friendly hydrophobic and superhydrophobic surfaces. The achieved hydrophobic membranes were very effective in the removal of VOCs (butanol, methyl-tert-butyl ether, and ethyl acetate) from binary aqueous solutions in vacuum membrane distillation. The correlation between membrane effectiveness and separated solvent polarity was compared in terms of material properties and resistance to the wetting (kinetics of wetting and in-depth liquid penetration). Material properties were interpreted considering Zisman theory and using Kao diagram. The significant influence of surface chemistry on the membrane performance was noticed (5 kDa, influence of hydrophobic nanolayer and separation controlled by solution-diffusion model; 300 kDa, no impact of surface chemistry and separation controlled by liquid-vapor equilibrium).

Environmental Remediation and Application of Nanoscale Zero-Valent Iron and Its Composites for the Removal of Heavy Metal Ions: A Review.

PubMed

Zou, Yidong; Wang, Xiangxue; Khan, Ayub; Wang, Pengyi; Liu, Yunhai; Alsaedi, Ahmed; Hayat, Tasawar; Wang, Xiangke

2016-07-19

The presence of heavy metals in the industrial effluents has recently been a challenging issue for human health. Efficient removal of heavy metal ions from environment is one of the most important issues from biological and environmental point of view, and many studies have been devoted to investigate the environmental behavior of nanoscale zerovalent iron (NZVI) for the removal of toxic heavy metal ions, present both in the surface and underground wastewater. The aim of this review is to show the excellent removal capacity and environmental remediation of NZVI-based materials for various heavy metal ions. A new look on NZVI-based materials (e.g., modified or matrix-supported NZVI materials) and possible interaction mechanism (e.g., adsorption, reduction and oxidation) and the latest environmental application. The effects of various environmental conditions (e.g., pH, temperature, coexisting oxy-anions and cations) and potential problems for the removal of heavy metal ions on NZVI-based materials with the DFT theoretical calculations and EXAFS technology are discussed. Research shows that NZVI-based materials have satisfactory removal capacities for heavy metal ions and play an important role in the environmental pollution cleanup. Possible improvement of NZVI-based materials and potential areas for future applications in environment remediation are also proposed.

Endodontic filling removal procedure: an ex vivo comparative study between two rotary techniques.

PubMed

Vale, Mônica Sampaio do; Moreno, Melinna dos Santos; Silva, Priscila Macêdo França da; Botelho, Thereza Cristina Farias

2013-01-01

In this study, we compared the ex vivo removal capacity of two endodontic rotary techniques and determined whether there was a significant quantitative difference in residual material when comparing root thirds. Forty extracted molars were used. The palatal roots were selected, and the canals were prepared using a step-back technique and filled using a lateral condensation technique with gutta-percha points and Endofill sealer. After two weeks of storage in a 0.9% saline solution at 37 ºC in an oven, the specimens were divided into 2 groups of 20, with group 1 samples subjected to Gates-Glidden drills and group 2 samples subjected to the ProTaper retreatment System. Hedstroem files and eucalyptol solvent were used in both groups to complete the removal procedure. Then, the roots thirds were radiographed and the images were submitted to the NIH ImageJ program to measure the residual filling material in mm. Each root third was related to the total area of the root canals. The data were analyzed using Student's t test. There was a statistically significant difference between the two techniques as more filling material was removed by technique 2 (ProTaper) than technique 1 (Gates-Glidden drills, p < 0.05). The apical third had a greater amount of residual filling material than the cervical and middle thirds, and the difference was statistically significant (p < 0.05). None of the selected techniques removed all filling material, and the material was most difficult to remove from the apical third. The ProTaper files removed more material than the Gates-Glidden drills.

Design of Microstructured Conducting Polymer Films for Enhanced Trace Explosives Detection

NASA Astrophysics Data System (ADS)

Laster, Jennifer S.

The detection of trace amounts of explosive material is critical to national security. Ion mobility spectrometer (IMS)-based contact sampling continues to be a common method employed for the detection of explosives in high security checkpoint applications, such as airport security. In this process a surface of interest, such as a passenger's hands or luggage, is probed by a swab or particle trap to collect and transfer residue to an IMS for analysis. The collection of residue on a sampling swab has been shown to be a limiting step in this detection process. As such, there is significant need to develop new materials with increased adhesion to explosive analytes and with superior particle removal abilities. Here, the design of novel sampling swabs is presented for the enhanced collection of trace explosive residue from surfaces. First, the influence of the swab microstructure on the ability to remove particles from representative substrates is demonstrated. Free-standing microstructured polypyrrole (PPy) films of a variety of dimensions and form factors are fabricated using a templated electropolymerization process. The removal of polystyrene fluorescent particles from an aluminum substrate of varying surface roughness is examined as a function of the polymer microstructure. PPy microstructured films display enhanced particle removal abilities compared to PPy non-structured and current commercial films. This increase in particle removal is attributed to the increased particle-swab contact from the microstructured films. Next, the influence of the surface chemistry of sampling swabs on the collection of a representative explosive analyte, trinitrotoluene (TNT) is explored. The surface chemistry of PPy films is modified by electropolymerizaton of an N-substituted pyrrole monomer. The surface chemistries examined include a methyl, carboxylic acid, and amino-phenyl functionality. The vapor deposition of TNT on the surface of the functionalized PPy films is quantified through ultraviolet-visible (UV-vis) absorption and compared to commercial swabbing materials of varying chemistry and surface roughness. The PPy modified films with potential sites for hydrogen bonding display the highest deposition of TNT, while the Teflon coated commercial films display the lowest interaction with TNT. Finally, the desorption and release of TNT from sampling swabs is studied as an effect of temperature and of applied bias. For successful analyte detection within an IMS, the residue collected on a sampling swab must be released from the swab, typically through a thermal desorption process. In this work the release of TNT from sampling swabs is determined through solid-phase microextraction-gas chromatography mass spectrometry (SPME-GCMS). The results of this thesis provide important information on the design considerations for the development of novel particle sampling swabs with increased performance.

Preparation of amine functionalized carbon nanotubes via a bioinspired strategy and their application in Cu2+ removal

NASA Astrophysics Data System (ADS)

Zhang, Xiaoyong; Huang, Qiang; Liu, Meiying; Tian, Jianwen; Zeng, Guangjian; Li, Zhen; Wang, Ke; Zhang, Qinsong; Wan, Qing; Deng, Fengjie; Wei, Yen

2015-07-01

The environmental applications of carbon nanotubes (CNTs) have attracted great research attention since their first discovery. However, the performance of pristine CNTs for removal of heavy metal ions is greatly limited by their severe aggregation and lack of functional groups. In this work, a novel method has been developed for preparation of amine functionalized CNTs via combination of mussel inspired chemistry and Michael addition reaction. CNTs were first coated with polydopamine (PDA) through mussel inspired chemistry. And then commercial available agent polyethylene polyamine with a number of amine groups was further conjugated with PDA coated CNTs via Michael addition reaction. A series of characterization techniques have demonstrated that the amine functionalized CNTs have been successfully prepared. Furthermore, the adsorption application of thus amine functionalized CNTs for Cu2+ was examined. The effects of various parameters including pH solution, temperature, initial Cu2+ concentration and the adsorbent concentration were investigated. The data from experiments were analyzed by the Langmuir and Freundlich models of adsorption. Due to the universal of mussel inspired chemistry, the method described in this work should be a general strategy for surface modification of materials for environmental applications.

Removal of Pb, Zn, and Cd from contaminated soil by new washing agent from plant material.

PubMed

Cao, Yaru; Zhang, Shirong; Wang, Guiyin; Huang, Qinling; Li, Ting; Xu, Xiaoxun

2017-03-01

Soil washing is an effective approach to remove soil heavy metals, and the washing agent is generally regarded as one of the primary factors in the process, but there is still a lack of efficient and eco-friendly agents for this technique. Here, we showed that four plant washing agents-from water extracts of Coriaria nepalensis (CN), Clematis brevicaudata (CB), Pistacia weinmannifolia (PW), and Ricinus communis (RC)-could be feasible agents for the removal of soil lead (Pb), zinc (Zn), and cadmium (Cd). The metal removal efficiencies of the agents increased with their concentrations from 20 to 80 g L -1 , decreased with the increasing solution pH, and presented different trends with the reaction time increasing. CN among the four agents had the highest removal efficiencies of soil Pb (62.02%) and Zn (29.18%) but owned the relatively low Cd removal efficiencies (21.59%). The Fourier transform infrared spectroscopy showed that the abilities of plant washing agents for the removal of soil heavy metals may result from bioactive substances with specific functional groups such as -COOH, -NH 2 , and -OH. Our study provided CN as the best washing agents for the remediation of contaminated soil by heavy metals.

Using MOF-74 for Hg{sup 2+} removal from ultra-low concentration aqueous solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiong, Yang Yang; Li, Jian Qiang; Gong, Le Le

Mercury (Hg{sup 2+}) ions have very high toxicity and widely spread as environmental pollutants. At present, many efforts have been taken to remove the hazardous materials of mercury(II) by adsorption, and it is highly desirable to develop a novel adsorbent with high adsorptive capacities. However it is still a big challenge to remove the ultra-low-concentration mercury ions from water. In this paper, MOF-74-Zn is explored for such function, showing high removal rate of Hg(II) from water without any pretreatment, especially for the ultra-trace Hg(II) ions in the ppb magnitude with the removal rate reaching to 54.48%, 69.71%, 72.26% when themore » initial concentration of Hg(II) is 20ppb, 40ppb, 50ppb, respectively. - Graphical abstract: The absorption of mercury ions on MOF-74-Zn is due to somewhat weak interactions between MOF skeleton that is composed of carboxylate and hydroxy group and Hg2+ ions. - Highlights: • MOF-74-Zn shows high removal rate of Hg(II) from water without any pretreatment. • The MOF-74-Zn has a notable performance at ultra-low concentration of Hg(II). • MOF-74-Zn shows the potential for Hg(II) removal from industrial waste water.« less

Mechanisms of material removal and mass transport in focused ion beam nanopore formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Kallol, E-mail: das7@illinois.edu; Johnson, Harley T., E-mail: htj@illinois.edu; Freund, Jonathan B., E-mail: jbfreund@illinois.edu

2015-02-28

Despite the widespread use of focused ion beam (FIB) processing as a material removal method for applications ranging from electron microscope sample preparation to nanopore processing for DNA sequencing, the basic material removal mechanisms of FIB processing are not well understood. We present the first complete atomistic simulation of high-flux FIB using large-scale parallel molecular dynamics (MD) simulations of nanopore fabrication in freestanding thin films. We focus on the root mechanisms of material removal and rearrangement and describe the role of explosive boiling in forming nanopores. FIB nanopore fabrication is typically understood to occur via sputter erosion. This can bemore » shown to be the case in low flux systems, where individual ion impacts are sufficiently separated in time that they may be considered as independent events. But our detailed MD simulations show that in high flux FIB processing, above a threshold level at which thermal effects become significant, the primary mechanism of material removal changes to a significantly accelerated, thermally dominated process. Under these conditions, the target is heated by the ion beam faster than heat is conducted away by the material, leading quickly to melting, and then continued heating to nearly the material critical temperature. This leads to explosive boiling of the target material with spontaneous bubble formation and coalescence. Mass is rapidly rearranged at the atomistic scale, and material removal occurs orders of magnitude faster than would occur by simple sputtering. While the phenomenology is demonstrated computationally in silicon, it can be expected to occur at lower beam fluxes in other cases where thermal conduction is suppressed due to material properties, geometry, or ambient thermal conditions.« less

Removal rate model for magnetorheological finishing of glass.

PubMed

Degroote, Jessica E; Marino, Anne E; Wilson, John P; Bishop, Amy L; Lambropoulos, John C; Jacobs, Stephen D

2007-11-10

Magnetorheological finishing (MRF) is a deterministic subaperture polishing process. The process uses a magnetorheological (MR) fluid that consists of micrometer-sized, spherical, magnetic carbonyl iron (CI) particles, nonmagnetic polishing abrasives, water, and stabilizers. Material removal occurs when the CI and nonmagnetic polishing abrasives shear material off the surface being polished. We introduce a new MRF material removal rate model for glass. This model contains terms for the near surface mechanical properties of glass, drag force, polishing abrasive size and concentration, chemical durability of the glass, MR fluid pH, and the glass composition. We introduce quantitative chemical predictors for the first time, to the best of our knowledge, into an MRF removal rate model. We validate individual terms in our model separately and then combine all of the terms to show the whole MRF material removal model compared with experimental data. All of our experimental data were obtained using nanodiamond MR fluids and a set of six optical glasses.

Adsorption of mixtures of nutrients and heavy metals in simulated urban stormwater by different filter materials.

PubMed

Reddy, Krishna R; Xie, Tao; Dastgheibi, Sara

2014-01-01

In recent years, several best management practices have been developed for the removal of different types of pollutants from stormwater runoff that lead to effective stormwater management. Filter materials that remove a wide range of contaminants have great potential for extensive use in filtration systems. In this study, four filter materials (calcite, zeolite, sand, and iron filings) were investigated for their adsorption and efficiency in the removal of nutrients and heavy metals when they exist individually versus when they co-exist. Laboratory batch experiments were conducted separately under individual and mixed contaminants conditions at different initial concentrations. Adsorption capacities varied under the individual and mixed contaminant conditions due to different removal mechanisms. Most filter materials showed lower removal efficiency under mixed contaminant conditions. In general, iron filings were found effective in the removal of nutrients and heavy metals simultaneously to the maximum levels. Freundlich and Langmuir isotherms were used to model the batch adsorption results and the former better fitted the experimental results. Overall, the results indicate that the filter materials used in this study have the potential to be effective media for the treatment of nutrients and heavy metals commonly found in urban stormwater runoff.

Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bortolaz de Oliveira, Henrique; Wypych, Fernando, E-mail: wypych@ufpr.br

Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO{sub 4}{sup 2−}/g of material, respectively. Although the removal values obtained for Zn/NiHN andmore » Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO{sub 4}{sup 2−}/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated. - Highlights: • Zinc hydroxide nitrate and Zn/Ni hydroxide nitrate or acetate were synthesized. • The interlayer anions were replaced by chromate anions at pH=8.0. • Only Zn/Ni hydroxide nitrate or acetate have the structure preserved after exchange. • Fast exchange reaction and high capacity of chromate removal were observed. • Magnetic materials were obtained to facilitate the solids removal the from solutions.« less

Optimal atomic structure of amorphous silicon obtained from density functional theory calculations

NASA Astrophysics Data System (ADS)

Pedersen, Andreas; Pizzagalli, Laurent; Jónsson, Hannes

2017-06-01

Atomic structure of amorphous silicon consistent with several reported experimental measurements has been obtained from annealing simulations using electron density functional theory calculations and a systematic removal of weakly bound atoms. The excess energy and density with respect to the crystal are well reproduced in addition to radial distribution function, angular distribution functions, and vibrational density of states. No atom in the optimal configuration is locally in a crystalline environment as deduced by ring analysis and common neighbor analysis, but coordination defects are present at a level of 1%-2%. The simulated samples provide structural models of this archetypal disordered covalent material without preconceived notion of the atomic ordering or fitting to experimental data.

Functionalization of super-aligned carbon nanotube film using hydrogen peroxide solution and its application in copper electrodeposition.

PubMed

Xiong, Lunqiao; Shuai, Jing; Hou, Zecheng; Zhu, Lin; Li, Wenzhen

2017-07-15

In order to make super-aligned carbon nanotubes (SACNT) homogeneously spread in electrolytes, a swift and effective method was devised for surface functionalization of SACNT film by ohmic heating using hydrogen peroxide solution. Controllable generation of defects and notable graft of oxygen functional groups on the sidewall of SACNTs were induced as proven by X-ray photoelectron spectroscopy and Raman spectroscopy. Differently from the harsh wet chemical oxidation, the super-aligned morphology and structural integrity of carbon nanotubes in the SACNT film were found to be well preserved by electron microscopy analysis. The functionalized treatment can remove extraneous material contaminating SACNT film and improve its conductivity. The grafting of polar ionizable groups has been proved to effectively eliminate the agglomeration of SACNTs. When the oxidized SACNT film was used as host material for electrodeposition of copper, the composite film of well-bonded SACNTs and Cu was successfully prepared. Copyright © 2017 Elsevier Inc. All rights reserved.

Chemical mechanisms of photocatalytic de-soiling and de-polluting processes in indoor environments and urban surfaces

NASA Astrophysics Data System (ADS)

Sleiman, M.; Rosseler, O.; Montesinos, N.; Litter, M.; Bikiel, D.; Kirchstetter, T.; Bluhm, H.; Ahmed, M.; Salmeron, M.; Destaillats, H.

2013-12-01

Photocatalysis has been postulated as a promising approach for the de-pollution of indoor air and urban atmospheres, and for self-cleaning surfaces. Building materials and coatings containing nano-sized TiO2 photocatalytic functionalities are gaining market share, including self-cleaning building envelope materials (coatings, mortar, plaster, architectural fabrics and tiles) and indoor air purifiers. While many studies have reported good performance of photocatalysis in the removal of organic pollutants from indoor air, more information is needed to understand secondary emissions of potentially harmful byproducts from photocatalytic air cleaners. This presentation will describe analytical methods and experimental results from room-sized chamber experiments using a realistic challenge VOC mixture at low ppb levels. We will also present results from separate studies that used synchrotron-based surface spectroscopic and mass spectrometric methods to better understand the photocatalytic mechanisms that regulate the de-soiling and de-polluting activity. Two photocatalytic processes were studied: de-noxification (NOx removal) and de-soiling (removal of deposited black carbon or soot). Ambient pressure XPS was used to study surface and gas-phase species formed during adsorption of NO2 on TiO2 and subsequent UV irradiation at λ = 365 nm. The results illustrate how NOx chemistry on TiO2 surfaces can be affected by the presence of water vapor, heteroatoms present as impurities, and carbonaceous soiling. The reactivity of NOx and NO3- on surfaces leads to reduced adsorbed and gas-phase nitrogenated species. These processes need to be considered in the engineering of depolluting materials and incorporated into atmospheric models. De-soiling properties were investigated by analyzing soot oxidation on TiO2 surfaces. Model soot samples were used as surrogates of urban grime. Using laser desorption coupled with time-of-flight (TOF) mass spectrometry synchrotron ionization, we investigated the mechanisms of photocatalytic soot removal under UVA irradiation. Ancillary reflectance measurements were performed to determine the efficiency and kinetics of soot removal.

Space environmental effects on silvered Teflon thermal control surfaces

NASA Technical Reports Server (NTRS)

Hemminger, C. S.; Stuckey, W. K.; Uht, J. C.

1992-01-01

Cumulative space environmental effects on silver/fluorinated ethylene propylene (Ag/FEP) were a function of exposure orientation. Samples from nineteen silvered Teflon (Ag/FEP) thermal control surfaces recovered from the Long Duration Exposure Facility (LDEF) were analyzed to determine changes in this material as a function of position on the spacecraft. Although solar absorptance and infrared emittance of measured thermal blanket specimens are relatively unchanged from control specimen values, significant changes in surface morphology, composition, and chemistry were observed. We hypothesize that the FEP surfaces on the LDEF are degraded by UV radiation at all orientations, but that the damaged material has been removed by erosion from the blankets exposed to atomic oxygen flux and that contamination is masking the damage in some areas on the trays flanking the trailing edge.

Removal and Disposal of An Environmental Carcinogen: Asbestos

ERIC Educational Resources Information Center

Fodero, Severio D.

1977-01-01

This article details the removal and disposal of asbestos ceiling material in a Yale University building. The removal process utilized a water and wetting agent technique used by firefighters and the debris disposal was in a sanitary landfill, following federal regulations for the handling of hazardous materials. (MA)

Identification of the function of extracellular polymeric substances (EPS) in denitrifying phosphorus removal sludge in the presence of copper ion.

PubMed

Wang, Yayi; Qin, Jian; Zhou, Shuai; Lin, Ximao; Ye, Liu; Song, Chengkang; Yan, Yuan

2015-04-15

Industrial wastewater containing heavy metals that enters municipal wastewater treatment plants inevitably has a toxic impact on biological treatment processes. In this study, the impact of Cu(II) (0, 1.5, 2, 2.5, 3 mg/L) on the performance of denitrifying phosphorus removal (DPR) and microbial community structures was investigated. Particularly, the dynamic change in the amount and composition of extracellular polymeric substances (EPS), and the role of EPS in P removal, were assessed using three-dimensional excitation-emission matrix fluorescence spectroscopy combined with parallel factor (PARAFAC) analysis. The results showed that, after long-term adjustment, the P removal efficiency was maintained at 95 ± 2.7% at Cu(II) addition up to 2.5 mg/L, but deteriorated when the Cu(II) addition was 3 mg/L. The EPS content, including proteins and humic substances, increased with increasing Cu(II) additions at concentrations ≤2.5 mg/L. This property of EPS was beneficial for protecting phosphate-accumulating organisms (PAOs) against heavy metals, as both proteins and humic substances are strong ligands for Cu(II). Therefore, the PAOs abundance was still relatively high (67 ± 3%) when Cu(II) accumulation in sludge was up to 10 mg/g SS. PARAFAC confirmed that aromatic proteins could be transformed into soluble microbial byproduct-like material when microorganisms were subjected to Cu(II) stress, owing to their strong metal ion complexing capacity. The increase in the percentage of humic-like substances enhanced the detoxification function of the sludge EPS. EPS accounted for approximately 26-47% of P removed by adsorption when Cu(II) additions were between 0 and 2.5 mg/L. The EPS function, including binding toxic heavy metals and P storage, enhanced the operating stability of DPR systems. This study provides us with a better understanding of (1) the tolerance of DPR sludge to copper toxicity and (2) the function of sludge EPS in the presence of heavy metals in biological P removal systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Porous Silica Sol-Gel Glasses Containing Reactive V2O5 Groups

NASA Technical Reports Server (NTRS)

Stiegman, Albert E.

1995-01-01

Porous silica sol-gel glasses into which reactive vanadium oxide functional groups incorporated exhibit number of unique characteristics. Because they bind molecules of some species both reversibly and selectively, useful as chemical sensors or indicators or as scrubbers to remove toxic or hazardous contaminants. Materials also oxidize methane gas photochemically: suggests they're useful as catalysts for conversion of methane to alcohol and for oxidation of hydrocarbons in general. By incorporating various amounts of other metals into silica sol-gel glasses, possible to synthesize new materials with broad range of new characteristics.

The influence of shrinkage-cracking on the drying behaviour of White Portland cement using Single-Point Imaging (SPI).

PubMed

Beyea, S D; Balcom, B J; Bremner, T W; Prado, P J; Cross, A R; Armstrong, R L; Grattan-Bellew, P E

1998-11-01

The removal of water from pores in hardened cement paste smaller than 50 nm results in cracking of the cement matrix due to the tensile stresses induced by drying shrinkage. Cracks in the matrix fundamentally alter the permeability of the material, and therefore directly affect the drying behaviour. Using Single-Point Imaging (SPI), we obtain one-dimensional moisture profiles of hydrated White Portland cement cylinders as a function of drying time. The drying behaviour of White Portland cement, is distinctly different from the drying behaviour of related concrete materials containing aggregates.

Hybrid biosorbents for removal of pollutants and remediation

NASA Astrophysics Data System (ADS)

Burlakovs, Juris; Klavins, Maris; Robalds, Artis; Ansone, Linda

2014-05-01

For remediation of soils and purification of polluted waters, wastewaters, biosorbents might be considered as prospective groups of materials. Amongst them peat have a special role due to low cost, biodegradability, high number of functional groups, well developed surface area and combination of hydrophilic/hydrophobic structural elements. Peat as sorbent have good application potential for removal of trace metals, and we have demonstrated peat sorption capacities, sorption kinetics, thermodynamics in respect to metals with different valencies - Tl(I), Cu(II), Cr(III). However, peat sorption capacity in respect to nonmetallic (anionic species) elements is low. Also peat mechanical properties do not support application in large scale column processes thereby, to expand peat application sphere, the approach of biomass based hybrid sorbents has been elaborated. The concept "hybrid sorbent" in understanding of biosorbent means natural, biomass based modified material, covered with another sorbent material, thus combining properties of both such as sorbent functionalities, surface properties etc. As the "covering layer" both inorganic substances, mineral phases (iron oxohydroxides, oxyappatite) and organic polymers (using graft polymerization) were used. The obtained sorbents were characterised by their spectral properties, surface area and elemental composition. The obtained hybrid sorbents were tested for sorption of compounds in anionic speciation forms, for example of arsenic, antimony, tellurium and phosphorous compounds in comparison with weakly basic anionites. The highest sorption capacity was observed when peat sorbents modified with iron compounds were used. Sorption of different arsenic speciation forms onto iron-modified peat sorbents was investigated as a function of pH and temperature. It was established that sorption capacity increases with a rise in temperature as the calculation of sorption process thermodynamic parameters indicates the spontaneity of sorption process and its endothermic nature. The recycling options of obtained compounds after their saturation with metal or non-metallic species are suggested.

Removal of metals from landfill leachate by sorption to activated carbon, bone meal and iron fines.

PubMed

Modin, Hanna; Persson, Kenneth M; Andersson, Anna; van Praagh, Martijn

2011-05-30

Sorption filters based on granular activated carbon, bone meal and iron fines were tested for their efficiency of removing metals from landfill leachate. Removal of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sr and Zn were studied in a laboratory scale setup. Activated carbon removed more than 90% of Co, Cr, Cu, Fe, Mn and Ni. Ca, Pb, Sr and Zn were removed but less efficiently. Bone meal removed over 80% of Cr, Fe, Hg, Mn and Sr and 20-80% of Al, Ca, Cu, Mo, Ni, Pb and Zn. Iron fines removed most metals (As, Ca, Co, Cr, Cu, Fe, Mg, Mn, Pb, Sr and Zn) to some extent but less efficiently. All materials released unwanted substances (metals, TOC or nutrients), highlighting the need to study the uptake and release of a large number of compounds, not only the target metals. To remove a wide range of metals using these materials two or more filter materials may need to be combined. Sorption mechanisms for all materials include ion exchange, sorption and precipitation. For iron fines oxidation of Fe(0) seems to be important for metal immobilisation. Copyright © 2011 Elsevier B.V. All rights reserved.

Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

NASA Astrophysics Data System (ADS)

de Oliveira, Henrique Bortolaz; Wypych, Fernando

2016-11-01

Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO42-/g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO42-/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated.

Electrorefiner

DOEpatents

Miller, W.E.; Tomczuk, Z.

1995-08-22

An apparatus is disclosed capable of functioning as a solid cathode and for removing crystalline structure from the upper surface of a liquid cathode, includes a metallic support vertically disposed with respect to an electrically insulating container capable of holding a liquid metal cathode. A piston of electrically insulating material mounted on the drive tube, surrounding the current lead, for vertical and rotational movement with respect thereto including a downwardly extending collar portion surrounding the metallic current lead. At least one portion of the piston remote from the metallic current lead being removed. Mechanism for lowering the piston to the surface of the liquid cathode and raising the piston from the surface along with mechanism for rotating the piston around its longitudinal axis. 5 figs.

Electrorefiner

DOEpatents

Miller, William E.; Tomczuk, Zygmunt

1995-01-01

An apparatus capable of functioning as a solid cathode and for removing crystalline structure from the upper surface of a liquid cathode, includes a metallic support vertically disposed with respect to an electrically insulating container capable of holding a liquid metal cathode. A piston of electrically insulating material mounted on the drive tube, surrounding the current lead, for vertical and rotational movement with respect thereto including a downwardly extending collar portion surrounding the metallic current lead. At least one portion of the piston remote from the metallic current lead being removed. Mechanism for lowering the piston to the surface of the liquid cathode and raising the piston from the surface along with mechanism for rotating the piston around its longitudinal axis.

Use of phosphorus-sorbing materials to remove phosphate from greenhouse wastewater.

PubMed

Dunets, C Siobhan; Zheng, Youbin; Dixon, Mike

2015-01-01

High phosphate content in wastewater is currently a major issue faced by the North American greenhouse industry. Phosphate-sorbing material filters could provide a means of removing phosphate from wastewater prior to discharge to the environment, but the characterization of economically viable materials and specific recommendations for greenhouse wastewater are not available. Batch and column experiments were used to examine the capacity of two calcium-based waste materials, basic oxygen furnace slag and a concrete waste material, to remove phosphate from greenhouse nutrient solution at varied operating conditions. Material columns operating at a hydraulic retention time (HRT) of 3 h consistently removed >99% of influent phosphate at a concentration of 60 mg/L over repeated applications and demonstrated high phosphate retention capacity (PRC) of 8.8 and 5.1 g P/kg for slag and concrete waste, respectively. Both materials also provided some removal of the micronutrients Fe, Mn and Zn. Increasing HRT to 24 h increased P retention capacity of slag to >10.5 g P/kg but did not improve retention by concrete waste. Decreasing influent phosphate concentration to 20 mg/L decreased PRC to 1.64 g P/kg in concrete waste columns, suggesting fluctuations in greenhouse wastewater composition will affect filter performance. The pH of filter effluent was closely correlated to final P concentration and can likely be used to monitor treatment effectiveness. This study demonstrated that calcium-based materials are promising for the removal of phosphate from greenhouse wastewater, and worthy of further research on scaling up the application to a full-sized system.

Elucidation of Factors Effecting Enzymatic Saccharification using Transgenic Hardwoods

NASA Astrophysics Data System (ADS)

Min, Douyong

Three groups of transgenic wood samples were used as starting materials to elucidate the recalcitrance of enzymatic saccharification with/without pretreatments. The first group of transgenic wood samples is low lignin P. trichocarpa. The second group is low xylan P. trichocarpa. The third one is 12 hybrid poplars which have different levels of S/V ratio and lignin content. Four pretreatments were carried out in this research including dilute sulfuric acid, green liquor, auto hydrolysis and ozone delignification. The behavior among pretreatments as a function of removal of lignin appears to be different. Lignin is the major factor of recalcitrance of the lignocellulosic material to ethanol conversion process. Xylan also plays key role in this process. In addition, the crude milled wood lignin was isolated from these three groups of transgenic samples. Lignin carbohydrate complexes was characterized by 1H-13C HMQC and 13C NMR. Thus the effect of LCCs on enzymatic saccharification was elucidated. High S/V ratio propels the lignin removal during pretreatments however; high S/V ratio retards the enzymatic saccharification on the lignocellulosic material without pretreatments. The level of LCCs linkages accounts for additional recalcitrance of the lignocellulosic material to ethanol conversion process. The amount of LCCs linkages is affected by xylan content, lignin content and S/V ratio.

Efficacy of ProTaper universal retreatment files in removing filling materials during root canal retreatment.

PubMed

Giuliani, Valentina; Cocchetti, Roberto; Pagavino, Gabriella

2008-11-01

The aim of this study was to evaluate the efficacy of the ProTaper Universal System rotary retreatment system and of Profile 0.06 and hand instruments (K-file) in the removal of root filling materials. Forty-two extracted single-rooted anterior teeth were selected. The root canals were enlarged with nickel-titanium (NiTi) rotary files, filled with gutta-percha and sealer, and randomly divided into 3 experimental groups. The filling materials were removed with solvent in conjunction with one of the following devices and techniques: the ProTaper Universal System for retreatment, ProFile 0.06, and hand instruments (K-file). The roots were longitudinally sectioned, and the image of the root surface was photographed. The images were captured in JPEG format; the areas of the remaining filling materials and the time required for removing the gutta-percha and sealer were calculated by using the nonparametric one-way Kruskal-Wallis test and Tukey-Kramer tests, respectively. The group that showed better results for removing filling materials was the ProTaper Universal System for retreatment files, whereas the group of ProFile rotary instruments yielded better root canal cleanliness than the hand instruments, even though there was no statistically significant difference. The ProTaper Universal System for retreatment and ProFile rotary instruments worked significantly faster than the K-file. The ProTaper Universal System for retreatment files left cleaner root canal walls than the K-file hand instruments and the ProFile Rotary instruments, although none of the devices used guaranteed complete removal of the filling materials. The rotary NiTi system proved to be faster than hand instruments in removing root filling materials.

Innovative and water based stripping approach for thick and bulk photoresists

NASA Astrophysics Data System (ADS)

Rudolph, Matthias; Schumann, Dirk; Thrun, Xaver; Esche, Silvio; Hohle, Christoph

2014-10-01

The usage of phase fluid based stripping agents to remove photoresists from silicon substrates was studied. Photoresists are required for many silicon based technologies such as MEMS patterning, 3D-Integration or frontend and backend of line semiconductor applications [1]. Although the use of resists is very common, their successful integration often depends on the ability to remove the resist after certain processing steps. On the one hand the resist is changing during subsequent process steps that can cause a thermally activated cross-linking which increases the stripping complexity. Resist removal is also challenging after the formation of a hard polymer surface layer during plasma or implant processes which is called skin or crust [2]. On the other hand the choice of stripping chemistry is often limited due to the presence of functional materials such as metals which can be damaged by aggressive stripping chemistries [3].

Versatile Cellulose-Based Carbon Aerogel for the Removal of Both Cationic and Anionic Metal Contaminants from Water.

PubMed

Alatalo, Sara-Maaria; Pileidis, Filoklis; Mäkilä, Ermei; Sevilla, Marta; Repo, Eveliina; Salonen, Jarno; Sillanpää, Mika; Titirici, Maria-Magdalena

2015-11-25

Hydrothermal carbonization of cellulose in the presence of the globular protein ovalbumin leads to the formation of nitrogen-doped carbon aerogel with a fibrillar continuous carbon network. The protein plays here a double role: (i) a natural source of nitrogen functionalities (2.1 wt %) and (ii) structural directing agent (S(BET) = 38 m(2)/g). The applicability in wastewater treatment, namely, for heavy metal removal, was examined through adsorption of Cr(VI) and Pb(II) ion solely and in a mixed bicomponent aqueous solutions. This cellulose-based carbogel shows an enhanced ability to remove both Cr(VI) (∼68 mg/g) and Pb(II) (∼240 mg/g) from the targeted solutions in comparison to other carbon materials reported in the literature. The presence of competing ions showed little effect on the adsorption efficiency toward Cr(VI) and Pb(II).

Non-equilibrium steady states in supramolecular polymerization

NASA Astrophysics Data System (ADS)

Sorrenti, Alessandro; Leira-Iglesias, Jorge; Sato, Akihiro; Hermans, Thomas M.

2017-06-01

Living systems use fuel-driven supramolecular polymers such as actin to control important cell functions. Fuel molecules like ATP are used to control when and where such polymers should assemble and disassemble. The cell supplies fresh ATP to the cytosol and removes waste products to sustain steady states. Artificial fuel-driven polymers have been developed recently, but keeping them in sustained non-equilibrium steady states (NESS) has proven challenging. Here we show a supramolecular polymer that can be kept in NESS, inside a membrane reactor where ATP is added and waste removed continuously. Assembly and disassembly of our polymer is regulated by phosphorylation and dephosphorylation, respectively. Waste products lead to inhibition, causing the reaction cycle to stop. Inside the membrane reactor, however, waste can be removed leading to long-lived NESS conditions. We anticipate that our approach to obtain NESS can be applied to other stimuli-responsive materials to achieve more life-like behaviour.

46 CFR 147A.31 - Removal of fumigation material and warning signs.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Removal of fumigation material and warning signs. 147A.31 Section 147A.31 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES INTERIM REGULATIONS FOR SHIPBOARD FUMIGATION After Ventilation § 147A.31 Removal of fumigation...

46 CFR 147A.31 - Removal of fumigation material and warning signs.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Removal of fumigation material and warning signs. 147A.31 Section 147A.31 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES INTERIM REGULATIONS FOR SHIPBOARD FUMIGATION After Ventilation § 147A.31 Removal of fumigation...

76 FR 15901 - Acquisition Regulation Miscellaneous Changes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-22

... obsolete material is being removed. DATES: Submit comments by May 23, 2011. ADDRESSES: You may submit... order to update references to other federal and Departmental directives, remove obsolete material and... efficient and transparent. This rule will not adversely affect in a material way the economy, productivity...

Bicarbonate of soda paint stripping process validation and material characterization

NASA Technical Reports Server (NTRS)

Haas, Michael N.

1995-01-01

The Aircraft Production Division at San Antonio Air Logistics Center has conducted extensive investigation into the replacement of hazardous chemicals in aircraft component cleaning, degreasing, and depainting. One of the most viable solutions is process substitution utilizing abrasive techniques. SA-ALC has incorporated the use of Bicarbonate of Soda Blasting as one such substitution. Previous utilization of methylene chloride based chemical strippers and carbon removal agents has been replaced by a walk-in blast booth in which we remove carbon from engine nozzles and various gas turbine engine parts, depaint cowlings, and perform various other functions on a variety of parts. Prior to implementation of this new process, validation of the process was performed, and materials and waste stream characterization studies were conducted. These characterization studies examined the effects of the blasting process on the integrity of the thin-skinned aluminum substrates, the effects of the process on both air emissions and effluent disposal, and the effects on the personnel exposed to the process.

Source-Free Exchange-Correlation Magnetic Fields in Density Functional Theory.

PubMed

Sharma, S; Gross, E K U; Sanna, A; Dewhurst, J K

2018-03-13

Spin-dependent exchange-correlation energy functionals in use today depend on the charge density and the magnetization density: E xc [ρ, m]. However, it is also correct to define the functional in terms of the curl of m for physical external fields: E xc [ρ,∇ × m]. The exchange-correlation magnetic field, B xc , then becomes source-free. We study this variation of the theory by uniquely removing the source term from local and generalized gradient approximations to the functional. By doing so, the total Kohn-Sham moments are improved for a wide range of materials for both functionals. Significantly, the moments for the pnictides are now in good agreement with experiment. This source-free method is simple to implement in all existing density functional theory codes.

Maintenance measures for preservation and recovery of permeable pavement surface infiltration rate--The effects of street sweeping, vacuum cleaning, high pressure washing, and milling.

PubMed

Winston, Ryan J; Al-Rubaei, Ahmed M; Blecken, Godecke T; Viklander, Maria; Hunt, William F

2016-03-15

The surface infiltration rates (SIR) of permeable pavements decline with time as sediment and debris clog pore spaces. Effective maintenance techniques are needed to ensure the hydraulic functionality and water quality benefits of this stormwater control. Eight different small-scale and full-scale maintenance techniques aimed at recovering pavement permeability were evaluated at ten different permeable pavement sites in the USA and Sweden. Maintenance techniques included manual removal of the upper 2 cm of fill material, mechanical street sweeping, regenerative-air street sweeping, vacuum street sweeping, hand-held vacuuming, high pressure washing, and milling of porous asphalt. The removal of the upper 2 cm of clogging material did not significantly improve the SIR of concrete grid paves (CGP) and permeable interlocking concrete pavers (PICP) due to the inclusion of fines in the joint and bedding stone during construction, suggesting routine maintenance cannot overcome improper construction. For porous asphalt maintenance, industrial hand-held vacuum cleaning, pressure washing, and milling were increasingly successful at recovering the SIR. Milling to a depth of 2.5 cm nearly restored the SIR for a 21-year old porous asphalt pavement to like-new conditions. For PICP, street sweepers employing suction were shown to be preferable to mechanical sweepers; additionally, maintenance efforts may become more intensive over time to maintain a threshold SIR, as maintenance was not 100% effective at removing clogging material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of plutonium from hepatic tissue

DOEpatents

Lindenbaum, Arthur; Rosenthal, Marcia W.

1979-01-01

A method is provided for removing plutonium from hepatic tissues by introducing into the body and blood stream a solution of the complexing agent DTPA and an adjunct thereto. The adjunct material induces aberrations in the hepatic tissue cells and removes intracellularly deposited plutonium which is normally unavailable for complexation with the DTPA. Once the intracellularly deposited plutonium has been removed from the cell by action of the adjunct material, it can be complexed with the DTPA present in the blood stream and subsequently removed from the body by normal excretory processes.

Enhanced adsorption of arsenic through the oxidative treatment of reduced aquifer solids.

PubMed

Huling, Jenna R; Huling, Scott G; Ludwig, Ralph

2017-10-15

Arsenic (As) contamination in drinking water is an epidemic in many areas of the world, especially Eastern Asian countries. Developing affordable and efficient procedures to remove arsenic from drinking water is critical to protect human health. In this study, the oxidation of aquifer solids through the use of sodium permanganate (NaMnO 4 ), hydrogen peroxide (H 2 O 2 ), and exposure to air, enhanced the adsorption of arsenic to the aquifer material resulting in treatment of the water. NaMnO 4 was more effective than H 2 O 2 . NaMnO 4 was tested at different loading rates (0.5, 1.5, 2.4, 3.4, and 4.9 g NaMnO 4 /kg aquifer material), and after 30 days contact time, arsenic removal ([As +3 ] INITIAL  = 610 μg/L) was 77%, 88%, 93%, 95%, 97%, respectively, relative to un-oxidized aquifer material. Arsenic removal increased with increasing contact time (30, 60, 90 days) suggesting removal was not reversible under the conditions of these experiments. Oxidative treatment by exposing the aquifer solids to air for 68 days resulted in >99% removal of Arsenic ([As +3 ] INITIAL  = 550 μg/L). Less arsenic removal (38.2%) was measured in the un-oxidized aquifer material. In-situ oxidation of aquifer materials using NaMnO 4 , or ex-situ oxidation of aquifer materials through exposure to air could be effective in the removal of arsenic in ground water and a potential treatment method to protect human health. Published by Elsevier Ltd.

MOLECULAR DYNAMICS SIMULATION AND EXPERIMENTAL STUDIES OF GOLD NANOPARTICLE TEMPLATED HDL-LIKE NANOPARTICLES FOR CHOLESTEROL (POSTPRINT)

DTIC Science & Technology

2016-12-21

STINFO COPY) AIR FORCE RESEARCH LABORATORY MATERIALS AND MANUFACTURING DIRECTORATE WRIGHT-PATTERSON AIR FORCE BASE, OH 45433-7750 AIR FORCE MATERIEL...9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING AGENCY ACRONYM(S) Air Force Research Laboratory...removing excess cholesterol from arterial plaques. Gold nanoparticles (AuNPs) functionalized with apolipoprotein A-I and with the lipids 1,2

Atmospheric methane removal by methane-oxidizing bacteria immobilized on porous building materials.

PubMed

Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Hoefman, Sven; De Vos, Paul; Boeckx, Pascal; Boon, Nico

2014-04-01

Biological treatment using methane-oxidizing bacteria (MOB) immobilized on six porous carrier materials have been used to mitigate methane emission. Experiments were performed with different MOB inoculated in building materials at high (~20 % (v/v)) and low (~100 ppmv) methane mixing ratios. Methylocystis parvus in autoclaved aerated concrete (AAC) exhibited the highest methane removal rate at high (28.5 ± 3.8 μg CH₄ g⁻¹ building material h⁻¹) and low (1.7 ± 0.4 μg CH₄ g⁻¹ building material h⁻¹) methane mixing ratio. Due to the higher volume of pores with diameter >5 μm compared to other materials tested, AAC was able to adsorb more bacteria which might explain for the higher methane removal observed. The total methane and carbon dioxide-carbon in the headspace was decreased for 65.2 ± 10.9 % when M. parvus in Ytong was incubated for 100 h. This study showed that immobilized MOB on building materials could be used to remove methane from the air and also act as carbon sink.

Decreased plant productivity resulting from plant group removal experiment constrains soil microbial functional diversity.

PubMed

Zhang, Ximei; Johnston, Eric R; Barberán, Albert; Ren, Yi; Lü, Xiaotao; Han, Xingguo

2017-10-01

Anthropogenic environmental changes are accelerating the rate of biodiversity loss on Earth. Plant diversity loss is predicted to reduce soil microbial diversity primarily due to the decreased variety of carbon/energy resources. However, this intuitive hypothesis is supported by sparse empirical evidence, and most underlying mechanisms remain underexplored or obscure altogether. We constructed four diversity gradients (0-3) in a five-year plant functional group removal experiment in a steppe ecosystem in Inner Mongolia, China, and quantified microbial taxonomic and functional diversity with shotgun metagenome sequencing. The treatments had little effect on microbial taxonomic diversity, but were found to decrease functional gene diversity. However, the observed decrease in functional gene diversity was more attributable to a loss in plant productivity, rather than to the loss of any individual plant functional group per se. Reduced productivity limited fresh plant resources supplied to microorganisms, and thus, intensified the pressure of ecological filtering, favoring genes responsible for energy production/conversion, material transport/metabolism and amino acid recycling, and accordingly disfavored many genes with other functions. Furthermore, microbial respiration was correlated with the variation in functional composition but not taxonomic composition. Overall, the amount of carbon/energy resources driving microbial gene diversity was identified to be the critical linkage between above- and belowground communities, contrary to the traditional framework of linking plant clade/taxonomic diversity to microbial taxonomic diversity. © 2017 John Wiley & Sons Ltd.

A novel anoxic-aerobic biofilter process using new composite packing material for the treatment of rural domestic wastewater.

PubMed

Pan, L T; Han, Y

2016-01-01

A pilot scale experiment was conducted to evaluate the characteristics of contaminants removal in a continuously two-stage biological process composed of an anoxic biofilter (AF) and an biological aerated filter (BAF). This novel process was developed by introducing new composite packing material (MZF) into bioreactors to treat rural domestic wastewater. A comparative study conducted by the same process with ceramsite as packing material under the same conditions showed that a MZF system with a Fe proportion in the packing material performed better in chemical oxygen demand (COD) removal (average 91.5%), ammonia (NH4(+)-N) removal (average 98.3%), total nitrogen (TN) removal (average 64.8%) and total phosphorus (TP) removal (average 90%). After treatment of the MZF system, the concentrations of COD, NH4(+)-N, TN and TP in effluent were 20.3 mg/L, 0.5 mg/L, 11.5 mg/L and 0.3 mg/L, respectively. The simultaneously high efficiencies of nitrification, denitrification and phosphorus removal were achieved by the coupling effects of biological and chemical processes in the MZF system. The results of this study showed that the application of MZF might be a favorable choice as packing material in biofilters for treatment of rural domestic wastewater.

Research on the material removal in the polishing of potassium dihydrogen phosphate crystals based on deliquescent action.

PubMed

Guo, Shaolong; Zhang, Feihu; Zhang, Yong; Luan, Dianrong

2014-01-01

Through the polishing experiments of potassium dihydrogen phosphate (KDP) crystals based on deliquescent action, the effect of several major factors, including crystal's initial surface state, polishing time, and revolution of polishing plate, on material removal was researched. Under certain experimental conditions, the rules of material removal were reached, and experimental results are discussed, which lays the foundation for popularization and application of polishing technology for KDP crystals based on deliquescent action.

Material removal in magnetorheological finishing of optics.

PubMed

Kordonski, William; Gorodkin, Sergei

2011-05-10

A concept of material removal based on the principle of conservation of particles momentum in a binary suspension is applied to analyze material removal in magnetorheological finishing and magnetorheological jet processes widely used in precision optics fabrication. According to this concept, a load for surface indentation by abrasive particles is provided at their interaction near the wall with heavier basic (magnetic) particles, which fluctuate (due to collision) in the shear flow of concentrated suspension. The model is in good qualitative and quantitative agreement with experimental results.

Method of making thermally removable epoxies

DOEpatents

Loy, Douglas A.; Wheeler, David R.; Russick, Edward M.; McElhanon, James R.; Saunders, Randall S.

2002-01-01

A method of making a thermally-removable epoxy by mixing a bis(maleimide) compound to a monomeric furan compound containing an oxirane group to form a di-epoxy mixture and then adding a curing agent at temperatures from approximately room temperature to less than approximately 90.degree. C. to form a thermally-removable epoxy. The thermally-removable epoxy can be easily removed within approximately an hour by heating to temperatures greater than approximately 90.degree. C. in a polar solvent. The epoxy material can be used in protecting electronic components that may require subsequent removal of the solid material for component repair, modification or quality control.

Assessment of farm soil, biochar, compost and weathered pine mulch to mitigate methane emissions.

PubMed

Syed, Rashad; Saggar, Surinder; Tate, Kevin; Rehm, Bernd H A

2016-11-01

Previous studies have demonstrated the effective utility of volcanic pumice soil to mitigate both high and low levels of methane (CH 4 ) emissions through the activity of both γ-proteobacterial (type I) and α-proteobacterial (type II) aerobic methanotrophs. However, the limited availability of volcanic pumice soil necessitates the assessment of other farm soils and potentially suitable, economical and widely available biofilter materials. The potential biofilter materials, viz. farm soil (isolated from a dairy farm effluent pond bank area), pine biochar, garden waste compost and weathered pine bark mulch, were inoculated with a small amount of volcanic pumice soil. Simultaneously, a similar set-up of potential biofilter materials without inoculum was studied to understand the effect of the inoculum on the ability of these materials to oxidise CH 4 and their effect on methanotroph growth and activity. These materials were incubated at 25 °C with periodic feeding of CH 4 , and flasks were aerated with air (O 2 ) to support methanotroph growth and activity by maintaining aerobic conditions. The efficiency of CH 4 removal was monitored over 6 months. All materials supported the growth and activity of methanotrophs. However, the efficiency of CH 4 removal by all the materials tested fluctuated between no or low removal (0-40 %) and high removal phases (>90 %), indicating biological disturbances rather than physico-chemical changes. Among all the treatments, CH 4 removal was consistently high (>80 %) in the inoculated farm soil and inoculated biochar, and these were more resilient to changes in the methanotroph community. The CH 4 removal from inoculated farm soil and inoculated biochar was further enhanced (up to 99 %) by the addition of a nutrient solution. Our results showed that (i) farm soil and biochar can be used as a biofilter material by inoculating with an active methanotroph community, (ii) an abundant population of α-proteobacterial methanotrophs is essential for effective and stable CH 4 removal and (iii) addition of nutrients enhances the growth and activity of methanotrophs in the biofilter materials. Further studies are underway to assess the feasibility of these materials at small plot and field scales.

Examination of Scanning Electron Microscope and Computed Tomography Images of PICA

NASA Technical Reports Server (NTRS)

Lawson, John W.; Stackpoole, Margaret M.; Shklover, Valery

2010-01-01

Micrographs of PICA (Phenolic Impregnated Carbon Ablator) taken using a Scanning Electron Microscope (SEM) and 3D images taken with a Computed Tomography (CT) system are examined. PICA is a carbon fiber based composite (Fiberform ) with a phenolic polymer matrix. The micrographs are taken at different surface depths and at different magnifications in a sample after arc jet testing and show different levels of oxidative removal of the charred matrix (Figs 1 though 13). CT scans, courtesy of Xradia, Inc. of Concord CA, were captured for samples of virgin PICA, charred PICA and raw Fiberform (Fig. 14). We use these images to calculate the thermal conductivity (TC) of these materials using correlation function (CF) methods. CF methods give a mathematical description of how one material is embedded in another and is thus ideally suited for modeling composites like PICA. We will evaluate how the TC of the materials changes as a function of surface depth. This work is in collaboration with ETH-Zurich, which has expertise in high temperature materials and TC modeling (including CF methods).

Surfactant anchoring and aggregate structure at silica nanoparticles: a persuasive facade for the adsorption of azo dye.

PubMed

Chaudhary, Savita; Sood, Aastha; Mehta, S K

2014-09-01

Nanotechnology's aptitude to silhouette matter at the scale of the nanometer has unlocked the flap to new inventions of applications in material science and nanomedicine. Engineered silica nanoparticles are key actor of this strategy. The amphitheatre of silica nanoparticles is inexplicably bilateral. Silica particles play essential function in everyday commercial purposes for instance energy storage, chemical and biological sensors, food processing and catalysis. One of the most appealing applications to emerge in the recent years is the use of silica particles for cleaning up contaminants in groundwater, soil and sediments. Herein this work, surfactant modified silica nanoparticles with unique surface and pore properties as well as high surface areas have been extensively investigated as an alternative for the dye removal. The physical and chemical characterizations of adsorbent have been studied using FTIR and scanning electron microscopy. The present investigation aims to explore the comparative effect of different surfactants during the formation of the target composite materials. The effects of various parameters like pH, adsorbent doses, dye concentration, addition of salt have also been investigated. These findings indicate that the nano silica particles are effective materials for dye removal and can be used to alleviate environmental problems.

Enhanced Removal of Lead by Chemically and Biologically Treated Carbonaceous Materials

PubMed Central

Mahmoud, Mohamed E.; Osman, Maher M.; Ahmed, Somia B.; Abdel-Fattah, Tarek M.

2012-01-01

Hybrid sorbents and biosorbents were synthesized via chemical and biological treatment of active carbon by simple and direct redox reaction followed by surface loading of baker's yeast. Surface functionality and morphology of chemically and biologically modified sorbents and biosorbents were studied by Fourier Transform Infrared analysis and scanning electron microscope imaging. Hybrid carbonaceous sorbents and biosorbents were characterized by excellent efficiency and superiority toward lead(II) sorption compared to blank active carbon providing a maximum sorption capacity of lead(II) ion as 500 μmol g−1. Sorption processes of lead(II) by these hybrid materials were investigated under the influence of several controlling parameters such as pH, contact time, mass of sorbent and biosorbent, lead(II) concentration, and foreign ions. Lead(II) sorption mechanisms were found to obey the Langmuir and BET isotherm models. The potential applications of chemically and biologically modified-active carbonaceous materials for removal and extraction of lead from real water matrices were also studied via a double-stage microcolumn technique. The results of this study were found to denote to superior recovery values of lead (95.0–99.0 ± 3.0–5.0%) by various carbonaceous-modified-bakers yeast biosorbents. PMID:22629157

Laser Processing of Multilayered Thermal Spray Coatings: Optimal Processing Parameters

NASA Astrophysics Data System (ADS)

Tewolde, Mahder; Zhang, Tao; Lee, Hwasoo; Sampath, Sanjay; Hwang, David; Longtin, Jon

2017-12-01

Laser processing offers an innovative approach for the fabrication and transformation of a wide range of materials. As a rapid, non-contact, and precision material removal technology, lasers are natural tools to process thermal spray coatings. Recently, a thermoelectric generator (TEG) was fabricated using thermal spray and laser processing. The TEG device represents a multilayer, multimaterial functional thermal spray structure, with laser processing serving an essential role in its fabrication. Several unique challenges are presented when processing such multilayer coatings, and the focus of this work is on the selection of laser processing parameters for optimal feature quality and device performance. A parametric study is carried out using three short-pulse lasers, where laser power, repetition rate and processing speed are varied to determine the laser parameters that result in high-quality features. The resulting laser patterns are characterized using optical and scanning electron microscopy, energy-dispersive x-ray spectroscopy, and electrical isolation tests between patterned regions. The underlying laser interaction and material removal mechanisms that affect the feature quality are discussed. Feature quality was found to improve both by using a multiscanning approach and an optional assist gas of air or nitrogen. Electrically isolated regions were also patterned in a cylindrical test specimen.

UltraForm Finishing (UFF) a 5-axis computer controlled precision optical component grinding and polishing system

NASA Astrophysics Data System (ADS)

Bechtold, Michael; Mohring, David; Fess, Edward

2007-05-01

OptiPro Systems has developed a new finishing process for the manufacturing of precision optical components. UltraForm Finishing (UFF) has evolved from a tire shaped tool with polishing material on its periphery, to its newest design, which incorporates a precision rubber wheel wrapped with a band of polishing material passing over it. Through our research we have developed a user friendly graphical interface giving the optician a deterministic path for finishing precision optical components. Complex UFF Algorithms combine the removal function and desired depth of removal into a motion controlled tool path which minimizes surface roughness and form errors. The UFF process includes 5 axes of computer controlled motion, (3 linear and 2 rotary) which provide the flexibility for finishing a variety of shapes including spheres, aspheres, and freeform optics. The long arm extension, along with a range of diameters for the "UltraWheel" provides a unique solution for the finishing of steep concave shapes such as ogives and domes. The UltraForm process utilizes, fixed and loose abrasives, in combination with our proprietary "UltraBelts" made of a range of materials such as polyurethane, felt, resin, diamond and others.

Protein-Based Nanofabrics for Multifunctional Air Filtering

NASA Astrophysics Data System (ADS)

Souzandeh, Hamid

With the fast development of economics and population, air pollution is getting worse and becomes a great concern worldwide. The release of chemicals, particulates and biological materials into air can lead to various diseases or discomfort to humans and other living organisms, alongside other serious impacts on the environment. Therefore, improving indoor air quality using various air filters is in critical need because people stay inside buildings most time of the day. However, current air filters using traditional polymers can only remove particles from the polluted air and disposing the huge amount of used air filters can cause serious secondary environmental pollution. Therefore, development of multi-functional air filter materials with environmental friendliness is significant. For this purpose, we developed "green" protein-based multifunctional air-filtering materials. The outstanding performance of the green materials in removal of multiple species of pollutants, including particulate matter, toxic chemicals, and biological hazards, simultaneously, will greatly facilitate the development of the next-generation air-filtration systems. First and foremost, we developed high-performance protein-based nanofabric air-filter mats. It was found that the protein-nanofabrics possess high-efficiency multifunctional air-filtering properties for both particles and various species of chemical gases. Then, the high-performance natural protein-based nanofabrics were promoted both mechanically and functionally by a textured cellulose paper towel. It is interestingly discovered that the textured cellulose paper towel not only can act as a flexible mechanical support, but also a type of airflow regulator which can improve the pollutant-nanofilter interactions. Furthermore, the protein-based nanofabrics were crosslinked in order to enhance the environmental-stability of the filters. It was found that the crosslinked protein-nanofabrics can significantly improve the structure stability against different moisture levels and temperatures, while maintain the multifunctional filtration performance. Moreover, it was demonstrated that the crosslinked protein-nanomaterials also possess antibacterial properties against the selected gram-negative and gram-positive bacteria. This provides a cost-effective solution for advanced "green" nanomaterials with excellent performance in both filtration functions and structure stability under varying environment. This work indicates that protein-based air-filters are promising "green" air-filtering materials for next-generation air-filtration systems.

Catalytic transformations of biomass substrates using mixed metal oxides derived from substituted hydrotalcites

NASA Astrophysics Data System (ADS)

Macala, Gerald Stephen, II

Fueled by seemingly endless reserves of cheap and easily accessible fossil energy, the industrial age has brought to the developed world tremendous advances in human health and well being. Unfortunately the burning of fossil fuels has also been implicated in increasing atmospheric CO2 concentrations and global climate change. Concerns about short-term and long-term supply further build a case for the need for alternative energy sources. Biomass derived materials are a tantalizing source of fuels and fine chemicals. Unlike petroleum derived hydrocarbons, biomass can be both renewable and carbon neutral. Crops can be regenerated annually or even more often in tropical climates, and since the captured carbon originates as atmospheric CO2, the overall cycle has the potential to be nearly carbon neutral regardless of the final fate of the carbon. In contrast to petroleum derived hydrocarbons, which can often be made more valuable by adding functionality, biomass derived materials are already highly functionalized and can usually be made more valuable by selective removal of functionality. The development of robust catalysts capable of selective defuntionalization of biomass derived substrates remains an important challenge with potentially enormous economic and societal impact. In addition to being robust and selective, catalysts should preferably be heterogeneous to allow for easier removal and regeneration after the reaction is complete. New materials consisting of Mg-Al hydrotalcite-like structures, with a limiting percentage of Mg or Al substituted with other M2+ or M3+ cations, were synthesized by a co-precipitation process in basic aqueous solution with carbonate as counterion. Calcination of these materials at 460 °C resulted in evolution of CO2 and water and yielded high surface area mixed metal oxides with enhanced reactivity. Materials were characterized by ICP for elemental analysis, XRD for structural information, XPS for surface elemental analysis and TEM for morphology. Substituting some of the Al for ferric ion resulted in enhanced basicity and enhanced reactivity towards transesterification of seed oil and the model compound triacetin. Substituting some of the Mg for cupric ion resulted in a transfer hydrogenation catalyst capable of single pot dehydrogenation of methanol and hydrogenation of the model compound dihydrobenzofuran.

40 CFR 257.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Domestic septage is either liquid or solid material removed from a septic tank, cesspool, portable toilet.... Domestic septage does not include liquid or solid material removed from a septic tank, cesspool, or similar...

Bagworm bags as portable armour against invertebrate predators.

PubMed

Sugiura, Shinji

2016-01-01

Some animals have evolved the use of environmental materials as "portable armour" against natural enemies. Portable bags that bagworm larvae (Lepidoptera: Psychidae) construct using their own silk and plant parts are generally believed to play an important role as a physical barrier against natural enemies. However, no experimental studies have tested the importance of bags as portable armour against predators. To clarify the defensive function, I studied the bagworm Eumeta minuscula and a potential predator Calosoma maximoviczi (Coleoptera: Carabidae). Under laboratory conditions, all bagworm larvae were attacked by carabid adults, but successfully defended themselves against the predators' mandibles using their own bags. The portable bags, which are composed mainly of host plant twigs, may function as a physical barrier against predator mandibles. To test this hypothesis, I removed the twig bags and replaced some with herb leaf bags; all bag-removed larvae were easily caught and predated by carabids, while all bag-replaced larvae could successfully defend themselves against carabid attacks. Therefore, various types of portable bags can protect bagworm larvae from carabid attacks. This is the first study to test the defensive function of bagworm portable bags against invertebrate predators.

Dynamic study of Cr(VI) removal performance and mechanism from water using multilayer material coated nanoscale zerovalent iron.

PubMed

Wu, Bin; Peng, Dinghua; Hou, Siyu; Tang, Bicong; Wang, Can; Xu, Heng

2018-05-16

In this study, the dynamic Cr(VI) removal process from water by the synthesized multilayer material coated nanoscale zerovalent iron (SBC-nZVI) was systematically discussed at different treatment conditions. The results showed that initial pH, contact time, Cr(VI) concentration and the dosage of SBC-nZVI were important parameters that influenced the Cr(VI) removal efficiency. The major Cr(VI) removal occurred within 60 min and gradually tend to equilibrium with consistent treatment. The removal efficiency was highly depended on pH values and the adsorption kinetics agreed well with the pseduo-second-order model (PSO). When the initial Cr(VI) concentration was below 15 mg/L, the removal rate could reach to about 100%. Moreover, the removal efficiency increased with the increase of SBC-nZVI dosage, which related to the increase of reactive sites. To understand the removal mechanism, SBC-nZVI before and after reaction with Cr(VI) were characterized by fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). These analysis showed that the interaction of SBC-nZVI with Cr(VI) was mainly controlled by reduction and electrostatic attraction. Therefore, these results explained the interaction between Cr(VI) and SBC-nZVI material in detail, and further proved that SBC-nZVI could be an effective material to remove Cr(VI) from water. Copyright © 2018. Published by Elsevier Ltd.

Removal Rate Model for Magnetorheological Finishing of Glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeGroote, J.E.; Marino, A.E.; WIlson, J.P.

2007-11-14

Magnetorheological finishing (MRF) is a deterministic subaperture polishing process. The process uses a magntorheological (MR) fluid that consists of micrometer-sized, spherical, magnetic carbonyl iron (CI) particles, nonmagnetic polishing abrasives, water, and stabilizers. Material removal occurs when the CI and nonmagnetic polishing abrasives shear material off the surface being polished. We introduce a new MRF material removal rate model for glass. This model contains terms for the near surface mechanical properties of glass, drag force, polishing abrasive size and concentration, chemical durability of the glass, MR fluid pH, and the glass composition. We introduce quantitative chemical predictors for the first time,more » to the best of our knowledge, into an MRF removal rate model. We validate individual terms in our model separately and then combine all of the terms to show the whole MRF material removal model compared with experimental data. All of our experimental data were obtained using nanodiamond MR fluids and a set of six optical glasses.« less

Porous Networks Through Colloidal Templates

NASA Astrophysics Data System (ADS)

Li, Qin; Retsch, Markus; Wang, Jianjun; Knoll, Wolfgang; Jonas, Ulrich

Porous networks represent a class of materials with interconnected voids with specific properties concerning adsorption, mass and heat transport, and spatial confinement, which lead to a wide range of applications ranging from oil recovery and water purification to tissue engineering. Porous networks with well-defined, highly ordered structure and periodicities around the wavelength of light can furthermore show very sophisticated optical properties. Such networks can be fabricated from a very large range of materials by infiltration of a sacrificial colloidal crystal template and subsequent removal of the template. The preparation procedures reported in the literature are discussed in this review and the resulting porous networks are presented with respect to the underlying material class. Furthermore, methods for hierarchical superstructure formation and functionalization of the network walls are discussed.

Investigation of ion-beam machining methods for replicated x-ray optics

NASA Technical Reports Server (NTRS)

Drueding, Thomas W.

1996-01-01

The final figuring step in the fabrication of an optical component involves imparting a specified contour onto the surface. This can be expensive and time consuming step. The recent development of ion beam figuring provides a method for performing the figuring process with advantages over standard mechanical methods. Ion figuring has proven effective in figuring large optical components. The process of ion beam figuring removes material by transferring kinetic energy from impinging neutral particles. The process utilizes a Kaufman type ion source, where a plasma is generated in a discharge chamber by controlled electric potentials. Charged grids extract and accelerate ions from the chamber. The accelerated ions form a directional beam. A neutralizer outside the accelerator grids supplies electrons to the positive ion beam. It is necessary to neutralize the beam to prevent charging workpieces and to avoid bending the beam with extraneous electro-magnetic fields. When the directed beam strikes the workpiece, material sputters in a predicable manner. The amount and distribution of material sputtered is a function of the energy of the beam, material of the component, distance from the workpiece, and angle of incidence of the beam. The figuring method described here assumes a constant beam removal, so that the process can be represented by a convolution operation. A fixed beam energy maintains a constant sputtering rate. This temporally and spatially stable beam is held perpendicular to the workpiece at a fixed distance. For non-constant removal, corrections would be required to model the process as a convolution operation. Specific figures (contours) are achieved by rastering the beam over the workpiece at varying velocities. A unique deconvolution is performed, using series-derivative solution developed for the system, to determine these velocities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drueding, T.W.

The final figuring step in the fabrication of an optical component involves imparting a specified contour onto the surface. This can be expensive and time consuming step. The recent development of ion beam figuring provides a method for performing the figuring process with advantages over standard mechanical methods. Ion figuring has proven effective in figuring large optical components. The process of ion beam figuring removes material by transferring kinetic energy from impinging neutral particles. The process utilizes a Kaufman type ion source, where a plasma is generated in a discharge chamber by controlled electric potentials. Charged grids extract and acceleratemore » ions from the chamber. The accelerated ions form a directional beam. A neutralizer outside the accelerator grids supplies electrons to the positive ion beam. It is necessary to neutralize the beam to prevent charging workpieces and to avoid bending the beam with extraneous electro-magnetic fields. When the directed beam strikes the workpiece, material sputters in a predicable manner. The amount and distribution of material sputtered is a function of the energy of the beam, material of the component, distance from the workpiece, and angle of incidence of the beam. The figuring method described here assumes a constant beam removal, so that the process can be represented by a convolution operation. A fixed beam energy maintains a constant sputtering rate. This temporally and spatially stable beam is held perpendicular to the workpiece at a fixed distance. For non-constant removal, corrections would be required to model the process as a convolution operation. Specific figures (contours) are achieved by rastering the beam over the workpiece at varying velocities. A unique deconvolution is performed, using series-derivative solution developed for the system, to determine these velocities.« less

Development of plasma chemical vaporization machining

NASA Astrophysics Data System (ADS)

Mori, Yuzo; Yamauchi, Kazuto; Yamamura, Kazuya; Sano, Yasuhisa

2000-12-01

Conventional machining processes, such as turning, grinding, or lapping are still applied for many materials including functional ones. But those processes are accompanied with the formation of a deformed layer, so that machined surfaces cannot perform their original functions. In order to avoid such points, plasma chemical vaporization machining (CVM) has been developed. Plasma CVM is a chemical machining method using neutral radicals, which are generated by the atmospheric pressure plasma. By using a rotary electrode for generation of plasma, a high density of neutral radicals was formed, and we succeeded in obtaining high removal rate of several microns to several hundred microns per minute for various functional materials such as fused silica, single crystal silicon, molybdenum, tungsten, silicon carbide, and diamond. Especially, a high removal rate equal to lapping in the mechanical machining of fused silica and silicon was realized. 1.4 nm (p-v) was obtained as a surface roughness in the case of machining a silicon wafer. The defect density of a silicon wafer surface polished by various machining method was evaluated by the surface photo voltage spectroscopy. As a result, the defect density of the surface machined by plasma CVM was under 1/100 in comparison with the surface machined by mechanical polishing and argon ion sputtering, and very low defect density which was equivalent to the chemical etched surface was realized. A numerically controlled CVM machine for x-ray mirror fabrication is detailed in the accompanying article in this issue.

Functionalized iron oxide/SBA-15 sorbent: investigation of adsorption performance towards glyphosate herbicide.

PubMed

Rivoira, Luca; Appendini, Marta; Fiorilli, Sonia; Onida, Barbara; Del Bubba, Massimo; Bruzzoniti, Maria Concetta

2016-11-01

Glyphosate is a worldwide-used herbicide occurring in many monitoring campaigns. Efficient technologies are currently unavailable for glyphosate removal from waters. In this work, a SBA-15 mesoporous silica-based material (Fe-NH 2 -SBA-15) was synthesized and studied for the adsorption of glyphosate from waters. In order to promote specific interactions between the sorbent and glyphosate via phosphoric group, iron oxide nanoparticles were encapsulated and a surface functionalization with (3-aminopropyl)triethoxysilane was accomplished. The adsorption of glyphosate on Fe-NH 2 -SBA-15 was investigated as a function of (i) pH, (ii) ionic strength (I), and (iii) adsorbate to adsorbent ratio (C), using a two-level, three-factor experimental design. The experimental design allowed for understanding the effect of the abovementioned variables and for proposing experimental conditions for quantitative removal (pH = 2.1, I = 1⋅10 -2  M and C = 0.35) under both batch and dynamic conditions. Interaction mechanism between glyphosate and Fe-NH 2 -SBA-15 sorbent was elucidated by studying the adsorption behavior of sorbents derived from the intermediate stages of synthesis and by desorption tests. Fe-NH 2 -SBA-15 sorbent can be quantitatively regenerated by 12.5 mM NaOH, and can be reused at least for five adsorption/desorption cycles. Quantitative removal of glyphosate from inlet and effluent wastewaters from a wastewater treatment plant is shown.

Novel synthesis of carbon spheres supported nanoscale zero-valent iron for removal of metronidazole

NASA Astrophysics Data System (ADS)

Wang, Xiangyu; Du, Yi; Ma, Jun

2016-12-01

For the first time, carbon spheres-supported nanoscale zero-valent iron (NZVI/CSs) were successfully synthesized as functionalized composite via liquid phase reduction method and adopted for removal of a typical antibiotic, metronidazole (MNZ), from wastewater. The resultant composite (NZVI/CSs) exhibit higher reactivity, excellent stability, enhanced dispersion, and improved longevity over the reaction course due to the presence of the charged carboxyl groups and hydroxyl groups on the surfaces of CSs. The results show that 94.18% of MNZ was removed using NZVI/CSs after 6 min, while only 36.45% and 8.78% of MNZ were removed using NZVI and CSs, respectively. The galvanic cell system between NZVI and CSs was essential for enhancing MNZ reduction in aqueous solution. Furthermore, the new findings include kinetics for MNZ removal by NZVI/CSs composite could be well expressed by a revised two-parameter pseudo-first-order model. Finally, the possible degradation mechanism was proposed, which was based on the analysis of degraded products by high performance liquid chromatography-mass spectrometry (HPLC-MS). Different important factors impacting on MNZ removal (including mass ratio of NZVI to CSs, initial concentration, pH value and solution temperature) were investigated as well. Overall, this study provides a promising alternative material and environmental pollution management option for antibiotic wastewater treatment.

Recent advances in degradable lactide-based shape-memory polymers.

PubMed

Balk, Maria; Behl, Marc; Wischke, Christian; Zotzmann, Jörg; Lendlein, Andreas

2016-12-15

Biodegradable polymers are versatile polymeric materials that have a high potential in biomedical applications avoiding subsequent surgeries to remove, for example, an implanted device. In the past decade, significant advances have been achieved with poly(lactide acid) (PLA)-based materials, as they can be equipped with an additional functionality, that is, a shape-memory effect (SME). Shape-memory polymers (SMPs) can switch their shape in a predefined manner upon application of a specific external stimulus. Accordingly, SMPs have a high potential for applications ranging from electronic engineering, textiles, aerospace, and energy to biomedical and drug delivery fields based on the perspectives of new capabilities arising with such materials in biomedicine. This study summarizes the progress in SMPs with a particular focus on PLA, illustrates the design of suitable homo- and copolymer structures as well as the link between the (co)polymer structure and switching functionality, and describes recent advantages in the implementation of novel switching phenomena into SMP technology. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation and characterization of functional material based on hybrid polymer composites

NASA Astrophysics Data System (ADS)

Agusu, La; Amiruddin; Taswito, Chen Chen; Herdianto; Zamrun, Muh.

2016-08-01

The microstructures and properties of hybrid polymer composites based on polyaniline (PANi)/γ-Fe2O3 nanoparticles/TiO2/carbon have been investigated for multifunctional applications such as heavy metal removal and initial study for radar absorbing material application. γ-Fe2O3 nanoparticles with spherical shape were synthetized by a coprecipitation method from iron sand. By activating the polyethylene glycol (PEG-400) coated carbon of coconut shell, the homogenous shape and size of carbon was achieved. Then, γ- Fe2O3, TiO2, and carbon were mixed with PANi by an in situ polymerization method at low temperature 0-5 oC. Characterization process involved XRD, SEM, FTIR, VSM, and DC conductivity measurements. For radar absorber application, the functionalized polymer composites showed good electrical conductivity 0.45 S/cm to absorb the incoming electromagnetic energy. An efficient and effective reduction of Pb2+ ion from the water has been achieved by using this material.

Nanoscale Graphene Disk: A Natural Functionally Graded Material-How is Fourier's Law Violated along Radius Direction of 2D Disk.

PubMed

Yang, Nuo; Hu, Shiqian; Ma, Dengke; Lu, Tingyu; Li, Baowen

2015-10-07

In this Paper, we investigate numerically and analytically the thermal conductivity of nanoscale graphene disks (NGDs), and discussed the possibility to realize functionally graded material (FGM) with only one material, NGDs. Different from previous studies on divergence/non-diffusive of thermal conductivity in nano-structures with different size, we found a novel non-homogeneous (graded) thermal conductivity along the radius direction in a single nano-disk structure. We found that, instead of a constant value, the NGD has a graded thermal conductivity along the radius direction. That is, Fourier's law of heat conduction is not valid in two dimensional graphene disk structures Moreover, we show the dependent of NGDs' thermal conductivity on radius and temperature. Our study might inspire experimentalists to develop NGD based versatile FGMs, improve understanding of the heat removal of hot spots on chips, and enhance thermoelectric energy conversion efficiency by two dimensional disk with a graded thermal conductivity.

Van der Waals Epitaxy of Functional Oxide Heterostructures

NASA Astrophysics Data System (ADS)

Chu, Ying-Hao

In the diligent pursuit of low-power consumption, multifunctional, and environmentally friendly electronics, more sophisticated requirements on functional materials are on demand. Recently, the discovery of 2D layered materials has created a revolution to this field. Pioneered by graphene, these new 2D materials exhibit abundant unusual physical phenomena that is undiscovered in bulk forms. These materials are characterized with their layer form and almost pure 2D electronic behavior. The confinement of charge and heat transport at such ultrathin planes offers possibilities to overcome the bottleneck of present device development in thickness limitation, and thus push the technologies into next generation. Van der Waals epitaxy, an epitaxial growth method to combine 2D and 3D materials, is one of current reliable manufacturing processes to fabricate 2D materials by growing these 2D materials epitaxially on 3D materials. Then, transferring the 2D materials to the substrates for practical applications. In the mean time, van der Waals epitaxy has also been used to create free-standing 3D materials by growing 3D materials on 2D materials and then removing them from 2D materials since the interfacial boding between 2D and 3D materials should be weak van der Waals bonds. In this study, we intend to take the same concept, but to integrate a family of functional materials in order to open new avenue to flexible electronics. Due to the interplay of lattice, charge, orbital, and spin degrees of freedom, correlated electrons in oxides generate a rich spectrum of competing phases and physical properties. Recently, lots of studies have suggested that oxide heterostructures provide a powerful route to create and manipulate the degrees of freedom and offer new possibilities for next generation devices, thus create a new playground for researchers to investigate novel physics and the emergence of fascinating states of condensed matter. In this talk, we use a 2D layered material as the substrate. And we take several oxides as examples to demonstrate a pathway to integrate 3D functional oxides on 2D layered materials.

Kinetics of natural organic matter (NOM) removal during drinking water biofiltration using different NOM characterization approaches.

PubMed

Chen, Fei; Peldszus, Sigrid; Elhadidy, Ahmed M; Legge, Raymond L; Van Dyke, Michele I; Huck, Peter M

2016-11-01

To better understand biofiltration, concentration profiles of various natural organic matter (NOM) components throughout a pilot-scale drinking water biofilter were investigated using liquid chromatography - organic carbon detection (LC-OCD) and fluorescence excitation and emission matrices (FEEM). Over a 2 month period, water samples were collected from six ports at different biofilter media depths. Results showed substantial removal of biopolymers (i.e. high molecular weight (MW) NOM components as characterized by LC-OCD) and FEEM protein-like materials, but low removal of humic substances, building blocks and low MW neutrals and low MW acids. For the first time, relative biodegradability of different NOM components characterized by LC-OCD and FEEM approaches were investigated across the entire MW range and for different fluorophore compositions, in addition to establishing the biodegradation kinetics. The removal kinetics for FEEM protein-like materials were different than for the LC-OCD-based biopolymers, illustrating the complementary nature of the LC-OCD and FEEM approaches. LC-OCD biopolymers (both organic carbon and organic nitrogen) and FEEM protein-like materials were shown to follow either first or second order biodegradation kinetics. Due to the low percent removal and small number of data points, the performance of three kinetic models was not distinguishable for humic substances. Pre-filtration of samples for FEEM analyses affected the removal behaviours and/or kinetics especially of protein-like materials which was attributed to the removal of the colloidal/particulate materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Poultry litter-based activated carbon for removing heavy metal ions in water.

PubMed

Guo, Mingxin; Qiu, Guannan; Song, Weiping

2010-02-01

Utilization of poultry litter as a precursor material to manufacture activated carbon for treating heavy metal-contaminated water is a value-added strategy for recycling the organic waste. Batch adsorption experiments were conducted to investigate kinetics, isotherms, and capacity of poultry litter-based activated carbon for removing heavy metal ions in water. It was revealed that poultry litter-based activated carbon possessed significantly higher adsorption affinity and capacity for heavy metals than commercial activated carbons derived from bituminous coal and coconut shell. Adsorption of metal ions onto poultry litter-based carbon was rapid and followed Sigmoidal Chapman patterns as a function of contact time. Adsorption isotherms could be described by different models such as Langmuir and Freundlich equations, depending on the metal species and the coexistence of other metal ions. Potentially 404 mmol of Cu2+, 945 mmol of Pb2+, 236 mmol of Zn2+, and 250-300 mmol of Cd2+ would be adsorbed per kg of poultry litter-derived activated carbon. Releases of nutrients and metal ions from litter-derived carbon did not pose secondary water contamination risks. The study suggests that poultry litter can be utilized as a precursor material for economically manufacturing granular activated carbon that is to be used in wastewater treatment for removing heavy metals.

Laboratory-Scale Column Testing Using IONSIV IE-911 for Removing Cesium from Acidic Tank Waste Simulant. 1: Cesium Exchange Capacity of a 15-cm3 Column and Dynamic Stability of the Exchange Media

DOE Office of Scientific and Technical Information (OSTI.GOV)

T.J. Tranter; R.D. Tillotson; T.A. Todd

2005-04-01

Bench-scale column tests were performed using a commercial form of crystalline silicotitanate (CST) for removing radio-cesium from a surrogate acidic tank solution representative of liquid waste stored at the Idaho National Engineering and Environmental Laboratory (INEEL). An engineered form of CST ion exchanger, known as IONSIVtm IE-911 (UOP, Mt Laurel, NJ, USA), was tested in 15 cm3 columns at a flow rate of 5 bed volumes per hour. These experiments showed the ion exchange material to have reasonable selectivity and capacity for removing cesium from the complex chemical matrix of the solution. However, previous testing indicated that partial neutralization ofmore » the feed stream was necessary to increase the stability of the ion exchange media. Thus, in these studies, CST degradation was determined as a function of throughput in order to better assess the stability characteristics of the exchanger for potential future waste treatment applications. Results of these tests indicate that the degradation of the CST reaches a maximum very soon after the acidic feed is introduced to the column and then rapidly declines. Total dissolution of bed material did not exceed 3% under the experimental regime used.« less

"MI" caries management--an overview.

PubMed

Banerjee, Avijit

2012-04-01

Minimum intervention dentistry, with its non-operative prevention and control of disease, underpins the basis of a patient-centred, team-based approach to managing dental caries in patients, who must take an active responsibility in maintaining their personal oral health. In patients where cavities are present causing pain, poor aesthetics and/or functional problems, restorations will need to be placed. Minimally invasive caries excavation strategies can be deployed depending on the patient's caries risk, lesion-pulp proximity and vitality, the extent of remaining supra-gingival tooth structure and clinical factors (e.g., moisture control, access) present in each case treated. Excavation instruments, including burs/handpieces, hand excavators, chemo-mechanical agents and/or air-abrasives which limit caries removal selectively to the more superficial caries-infected dentine and partial removal of caries-affected dentine when required, help create smaller cavities with healthy enamel/dentine margins. Using adhesive restorative materials, the operator can, if handling with care, optimize the histological substrate coupled with the applied chemistry of the material so helping to form a durable peripheral seal and bond to aid retention of the restoration as well as arresting the carious process within the remaining tooth structure. Achieving a smooth tooth-restoration interface clinically to aid the co-operative, motivated patient in biofilm removal, is an essential pre-requisite to prevent further secondary caries.

Cleaning efficacy of reciprocal and rotary systems in the removal of root canal filling material

PubMed Central

Koçak, Mustafa Murat; Koçak, Sibel; Türker, Sevinç Aktemur; Sağlam, Baran Can

2016-01-01

Aim: The aim of this study was to compare the efficacy of hand file, nickel titanium rotary instrument, and two reciprocating instruments for removing gutta-percha and sealer from the root canals. Materials and Methods: Eighty-eight mandibular premolar teeth were used. The root canals were shaped and filled with gutta-percha and a resin-based sealer. The specimens were divided into four groups according to the technique by which the root filling material was removed: Group 1 — Wave One; Group 2 — Reciproc; Group 3 — ProTaper; and Group 4 — Gates-Glidden burs and stainless steel hand file. Then teeth were split longitudinally and photographed. The images were transferred to a computer. The ratio of remaining filling material to the root canal periphery was calculated with the aid of ImageJ software. Statistical analysis was performed using Kruskal–Wallis and Mann–Whitney tests. Results: A significant difference was found among all groups (P < 0.001). The WaveOne group demonstrated significantly less remaining filling material. The greatest amount of filling material was found in specimens where gutta-percha was removed with Gates-Glidden burs and stainless steel hand file. Conclusion: The reciprocating files were found to be significantly more effective in removing the filling material from the canal walls compared to the rotational file and hand file. PMID:27099429

Explicit robust schemes for implementation of a class of principal value-based constitutive models: Symbolic and numeric implementation

NASA Technical Reports Server (NTRS)

Arnold, S. M.; Saleeb, A. F.; Tan, H. Q.; Zhang, Y.

1993-01-01

The issue of developing effective and robust schemes to implement a class of the Ogden-type hyperelastic constitutive models is addressed. To this end, special purpose functions (running under MACSYMA) are developed for the symbolic derivation, evaluation, and automatic FORTRAN code generation of explicit expressions for the corresponding stress function and material tangent stiffness tensors. These explicit forms are valid over the entire deformation range, since the singularities resulting from repeated principal-stretch values have been theoretically removed. The required computational algorithms are outlined, and the resulting FORTRAN computer code is presented.

Evolution of surface characteristics in material removal simulation with subaperture tools

NASA Astrophysics Data System (ADS)

Kim, Sug-Whan; Jee, Myung-Kook

2002-02-01

Over the last decade, we have witnessed that the fabrication of 200 - 2000 mm scale have received relatively little attention from the fabrication technology development, compared to those of smaller than 200 mm and of larger than 2000 mm in diameter. As a result, the optical surfaces of these scales are still predominantly completed by small optics shops where opticians apply the traditional technique for polishing. Lack of tools in aiding opticians for planning, executing and analyzing their polishing work is a root cause for long and, sometimes, unpredictable delivery and high manufacturing cost for such optical surfaces. We present the on-going development of a software simulation environment called Surface Analysis and Fabrication Environment (SAFE). It is primarily intended to increase the throughput of polishing and testing cycles by allowing opticians to simulate the resulting surface form and roughness with input polishing variables. A brief review of current polishing techniques and their target optics clarifies the need for such simulation tool. This is followed by the development targets and a preliminary simulation plan using the developmental version of SAFE. Among many polishing variables, two removal assumptions and three different types of removal functions we used for the polishing simulation presented. The simulations show that the Gaussian removal function with the proportional removal assumption resulted in the fastest, though marginal, convergence to a super-polished surface of 0.56 micron Peat- to-Valley in form accuracy and of 0.02 nanometer in surface roughness Ra. Other meaningful results and their implications are also presented.

Neutron vibrational spectroscopic studies of novel tire-derived carbon materials.

PubMed

Li, Yunchao; Cheng, Yongqiang; Daemen, Luke L; Veith, Gabriel M; Levine, Alan M; Lee, Richard J; Mahurin, Shannon M; Dai, Sheng; Naskar, Amit K; Paranthaman, Mariappan Parans

2017-08-23

Sulfonated tire-derived carbons have been demonstrated to be high value-added carbon products of tire recycling in several energy storage system applications including lithium, sodium, potassium ion batteries and supercapacitors. In this communication, we compared different temperature pyrolyzed sulfonated tire-derived carbons with commercial graphite and unmodified/non-functionalized tire-derived carbon by studying the surface chemistry and properties, vibrational spectroscopy of the molecular structure, chemical bonding such as C-H bonding, and intermolecular interactions of the carbon materials. The nitrogen adsorption-desorption studies revealed the tailored micro and meso pore size distribution of the carbon during the sulfonation process. XPS and neutron vibrational spectra showed that the sulfonation of the initial raw tire powders could remove the aliphatic hydrogen containing groups ([double bond splayed left]CH 2 and -CH 3 groups) and reduce the number of heteroatoms that connect to carbon. The absence of these functional groups could effectively improve the first cycle efficiency of the material in rechargeable batteries. Meanwhile, the introduced -SO 3 H functional group helped in producing terminal H at the edge of the sp 2 bonded graphite-like layers. This study reveals the influence of the sulfonation process on the recovered hard carbon from used tires and provides a pathway to develop and improve advanced energy storage materials.

Functional energy nanocomposites surfaces based on mesoscopic microspheres, polymers and graphene flakes

NASA Astrophysics Data System (ADS)

Alekseev, S. A.; Dmitriev, A. S.; Dmitriev, A. A.; Makarov, P. G.; Mikhailova, I. A.

2017-11-01

In recent years, there has been a great interest in the development and creation of new functional energy materials, including for improving the energy efficiency of power equipment and for effectively removing heat from energy devices, microelectronics and optoelectronics (power micro electronics, supercapacitors, cooling of processors, servers and Data centers). In this paper, the technology of obtaining a new nanocomposite based on mesoscopic microspheres, polymers and graphene flakes is considered. The methods of sequential production of functional materials from graphite flakes of different volumetric concentration using polymers based on epoxy resins and polyimide, as well as the addition of a mesoscopic medium in the form of monodisperse microspheres are described. The data of optical and electron microscopy of such nanocomposites are presented, the main problems in the appearance of defects in such materials are described, the possibilities of their elimination by the selection of different concentrations and sizes of the components. Data are given on the measurement of the hysteresis of the contact angle and the evaporation of droplets on similar substrates. The results of studying the mechanical, electrophysical and thermal properties of such nanocomposites are presented. Particular attention is paid to the investigation of the thermal conductivity of these nanocomposites with respect to the creation of thermal interface materials for cooling devices of electronics, optoelectronics and power engineering.

Synthesis and structure of pyridine-functionalized mesoporous SBA-15 organosilicas and their application for sorption of diclofenac

NASA Astrophysics Data System (ADS)

Barczak, Mariusz

2018-02-01

A series of pyridine-functionalized mesoporous silicas have been prepared for the first time via direct co-condensation of tetraethoxysilane (TEOS) and 2-(2-pyridyl)ethyltrimethoxysilane (PETS) using the block copolymer Pluronic P123 as a structure-directing agent. The obtained materials were fully characterized by a wide range of instrumental techniques and employed as adsorbents for the removal of a diclofenac which is considered a priority hazardous drug. The synthesized materials exhibit a high adsorption capacities and rapid adsorption rates. The structural and adsorption properties depend largely on the relative amount of PETS/TEOS ratio: the gradual degradation of ordered structure and porosity was observed with the increasing amount of PETS. However due to the highest loading of pyridine units the most structurally degraded material had the highest adsorption uptake (631 mg g-1) indicating that the surface chemistry plays - along with porosity - an important role in governing the adsorption process. The experimental adsorption data were modelled using the Langmuir, Freundlich and Langmuir-Freundlich isotherms - among them the Langmuir-Freundlich model turned out to be the most suitable for describing adsorption behaviour of diclofenac onto the materials. The collected data show that the pyridine-functionalized mesoporous silicas can be a promising absorbent of pharmaceuticals.

Effects of surface removal on rolling-element fatigue

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

1987-01-01

The Lundberg-Palmgren equation was modified to show the effect on rolling-element fatigue life of removing by grinding a portion of the stressed volume of the raceways of a rolling-element bearing. Results of this analysis show that depending on the amount of material removed, and depending on the initial running time of the bearing when material removal occurs, the 10-percent life of the reground bearings ranges from 74 to 100 percent of the 10-percent life of a brand new bearing. Three bearing types were selected for testing. A total of 250 bearings were reground. Of this matter, 30 bearings from each type were endurance tested to 1600 hr. No bearing failure occurred related to material removal. Two bearing failures occurred due to defective rolling elements and were typical of those which may occur in new bearings.

Water hyacinths and alligator weeds for removal of lead and mercury from polluted waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolverton, B.C.; McDonald, R.C.

1975-04-11

Removal of lead and mercury by water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb. was investigated. Water hyacinths demonstrated the ability to remove 0.176 mg of lead and 0.150 mg of mercury per gram of dry plant material from distilled water and river water in a 24-hour period. One acre of water hyacinths is potentially capable of removing 105.6 grams of lead and 90.0 grams of mercury per day. Alligator weeds removed 0.101 mg of lead per gram of dry plant material in a 24-hour period. This same plant also demonstrated the ability to removemore » a minimum of 0.153 mg of mercury per gram of dry plant material in a six hour period. (STAR)« less

Tribochemical investigation of microelectronic materials

NASA Astrophysics Data System (ADS)

Kulkarni, Milind Sudhakar

To achieve efficient planarization with reduced device dimensions in integrated circuits, a better understanding of the physics, chemistry, and the complex interplay involved in chemical mechanical planarization (CMP) is needed. The CMP process takes place at the interface of the pad and wafer in the presence of the fluid slurry medium. The hardness of Cu is significantly less than the slurry abrasive particles which are usually alumina or silica. It has been accepted that a surface layer can protect the Cu surface from scratching during CMP. Four competing mechanisms in materials removal have been reported: the chemical dissolution of Cu, the mechanical removal through slurry abrasives, the formation of thin layer of Cu oxide and the sweeping surface material by slurry flow. Despite the previous investigation of Cu removal, the electrochemical properties of Cu surface layer is yet to be understood. The motivation of this research was to understand the fundamental aspects of removal mechanisms in terms of electrochemical interactions, chemical dissolution, mechanical wear, and factors affecting planarization. Since one of the major requirements in CMP is to have a high surface finish, i.e., low surface roughness, optimization of the surface finish in reference to various parameters was emphasized. Three approaches were used in this research: in situ measurement of material removal, exploration of the electropotential activation and passivation at the copper surface and modeling of the synergistic electrochemical-mechanical interactions on the copper surface. In this research, copper polishing experiments were conducted using a table top tribometer. A potentiostat was coupled with this tribometer. This combination enabled the evaluation of important variables such as applied pressure, polishing speed, slurry chemistry, pH, materials, and applied DC potential. Experiments were designed to understand the combined and individual effect of electrochemical interactions as well as mechanical impact during polishing. Extensive surface characterization was performed with AFM, SEM, TEM and XPS. An innovative method for direct material removal measurement on the nanometer scale was developed and used. Experimental observations were compared with the theoretically calculated material removal rate values. The synergistic effect of all of the components of the process, which result in a better quality surface finish was quantitatively evaluated for the first time. Impressed potential during CMP proved to be a controlling parameter in the material removal mechanism. Using the experimental results, a model was developed, which provided a practical insight into the CMP process. The research is expected to help with electrochemical material removal in copper planarization with low-k dielectrics.

Removing nickel from nickel-coated carbon fibers

NASA Astrophysics Data System (ADS)

Hardianto, A.; Hertleer, C.; De Mey, G.; Van Langenhove, L.

2017-10-01

Conductive fibers/yarns are one of the most important materials for smart textiles because of their electrically conductive functionality combined with flexibility and light weight. They can be applied in many fields such as the medical sector, electronics, sensors and even as thermoelectric generators. Temperature sensors, for example, can be made using the thermocouple or thermopile principle which usually uses two different metal wires that can produce a temperature-dependent voltage. However, if metal wires are inserted into a textile structure, they will decrease the flexibility properties of the textile product. Nickel-coated Carbon Fiber (NiCF), a conductive textile yarn, has a potential use as a textile-based thermopile if we can create an alternating region of carbon and nickel along the fiber which in turn it can be used for substituting the metallic thermopile. The idea was to remove nickel from NiCF in order to obtain a yarn that contains alternating zones of carbon and nickel. Due to no literature reporting on how to remove nickel from NiCF, in this paper we investigated some chemicals to remove nickel from NiCF.

POTENTIAL IMPACT OF BLENDING RESIDUAL SOLIDS FROM TANKS 18/19 MOUNDS WITH TANK 7 OPERATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eibling, R; Erich Hansen, E; Bradley Pickenheim, B

2007-03-29

High level waste tanks 18F and 19F have residual mounds of waste which may require removal before the tanks can be closed. Conventional slurry pump technology, previously used for waste removal and tank cleaning, has been incapable of removing theses mounds from tanks 18F and 19F. A mechanical cleaning method has been identified that is potentially capable of removing and transferring the mound material to tank 7F for incorporation in a sludge batch for eventual disposal in high level waste glass by the Defense Waste Processing Facility. The Savannah River National Laboratory has been requested to evaluate whether the materialmore » transferred from tanks 18F/19F by the mechanical cleaning technology can later be suspended in Tank 7F by conventional slurry pumps after mixing with high level waste sludge. The proposed mechanical cleaning process for removing the waste mounds from tanks 18 and 19 may utilize a high pressure water jet-eductor that creates a vacuum to mobilize solids. The high pressure jet is also used to transport the suspended solids. The jet-eductor system will be mounted on a mechanical crawler for movement around the bottom of tanks 18 and 19. Based on physical chemical property testing of the jet-eductor system processed IE-95 zeolite and size-reduced IE-95 zeolite, the following conclusions were made: (1) The jet-eductor system processed zeolite has a mean and median particle size (volume basis) of 115.4 and 43.3 microns in water. Preferential settling of these large particles is likely. (2) The jet-eductor system processed zeolite rapidly generates settled solid yield stresses in excess of 11,000 Pascals in caustic supernates and will not be easily retrieved from Tank 7 with the existing slurry pump technology. (3) Settled size-reduced IE-95 zeolite (less than 38 microns) in caustic supernate does not generate yield stresses in excess of 600 Pascals in less than 30 days. (4) Preferential settling of size-reduced zeolite is a function of the amount of sludge and the level of dilution for the mixture. (5) Blending the size-reduced zeolite into larger quantities of sludge can reduce the amount of preferential settling. (6) Periodic dilution or resuspension due to sludge washing or other mixing requirements will increase the chances of preferential settling of the zeolite solids. (7) Mixtures of Purex sludge and size-reduced zeolite did not produce yield stresses greater than 200 Pascals for settling times less than thirty days. Most of the sludge-zeolite blends did not exceed 50 Pascals. These mixtures should be removable by current pump technology if sufficient velocities can be obtained. (8) The settling rate of the sludge-zeolite mixtures is a function of the ionic strength (or supernate density) and the zeolite- sludge mixing ratio. (9) Simulant tests indicate that leaching of Si may be an issue for the processed Tank 19 mound material. (10) Floating zeolite fines observed in water for the jet-eductor system and size-reduced zeolite were not observed when the size-reduced zeolite was blended with caustic solutions, indicating that the caustic solutions cause the fines to agglomerate. Based on the test programs described in this report, the potential for successfully removing Tank 18/19 mound material from Tank 7 with the current slurry pump technology requires the reduction of the particle size of the Tank 18/19 mound material.« less

40 CFR Appendix A to Subpart M of... - Interpretive Rule Governing Roof Removal Operations

Code of Federal Regulations, 2011 CFR

2011-07-01

... condition of the material at the time of demolition or renovation, (2) the nature of the operation to which... roofing materials. C. Cutting vs. Slicing and Manual Methods for Removal of Category I ACM 1.C.1. Because.... However, EPA believes that few roof removal jobs constitute “demolitions” as defined in the NESHAP (§ 61...

40 CFR Appendix A to Subpart M of... - Interpretive Rule Governing Roof Removal Operations

Code of Federal Regulations, 2013 CFR

2013-07-01

... condition of the material at the time of demolition or renovation, (2) the nature of the operation to which... roofing materials. C. Cutting vs. Slicing and Manual Methods for Removal of Category I ACM 1.C.1. Because.... However, EPA believes that few roof removal jobs constitute “demolitions” as defined in the NESHAP (§ 61...

40 CFR Appendix A to Subpart M of... - Interpretive Rule Governing Roof Removal Operations

Code of Federal Regulations, 2014 CFR

2014-07-01

... condition of the material at the time of demolition or renovation, (2) the nature of the operation to which... roofing materials. C. Cutting vs. Slicing and Manual Methods for Removal of Category I ACM 1.C.1. Because.... However, EPA believes that few roof removal jobs constitute “demolitions” as defined in the NESHAP (§ 61...

40 CFR Appendix A to Subpart M of... - Interpretive Rule Governing Roof Removal Operations

Code of Federal Regulations, 2012 CFR

2012-07-01

... condition of the material at the time of demolition or renovation, (2) the nature of the operation to which... roofing materials. C. Cutting vs. Slicing and Manual Methods for Removal of Category I ACM 1.C.1. Because.... However, EPA believes that few roof removal jobs constitute “demolitions” as defined in the NESHAP (§ 61...

Experiments and observations regarding the mechanisms of glass removal in magnetorheological finishing.

PubMed

Shorey, A B; Jacobs, S D; Kordonski, W I; Gans, R F

2001-01-01

Recent advances in the study of the magnetorheological finishing (MRF) have allowed for the characterization of the dynamic yield stress of the magnetorheological (MR) fluid, as well as the nanohardness (H(nano)) of the carbonyl iron (CI) used in MRF. Knowledge of these properties has allowed for a more complete study of the mechanisms of material removal in MRF. Material removal experiments show that the nanohardness of CI is important in MRF with nonaqueous MR fluids with no nonmagnetic abrasives, but is relatively unimportant in aqueous MR fluids or when nonmagnetic abrasives are present. The hydrated layer created by the chemical effects of water is shown to change the way material is removed by hard CI as the MR fluid transitions from a nonaqueous MR fluid to an aqueous MR fluid. Drag force measurements and atomic force microscope scans demonstrate that, when added to a MR fluid, nonmagnetic abrasives (cerium oxide, aluminum oxide, and diamond) are driven toward the workpiece surface because of the gradient in the magnetic field and hence become responsible for material removal. Removal rates increase with the addition of these polishing abrasives. The relative increase depends on the amount and type of abrasive used.

Using microabrasive material to remove fluorosis stains.

PubMed

Allen, Kenneth; Agosta, Claudine; Estafan, Denise

2004-03-01

Increased public access to fluoride has decreased the prevalence of caries and increased the prevalence of fluorosis staining. This article provides a case report involving a conservative method of removing fluorosis stain, as well as describes an in vitro test of the method. A healthy man sought treatment at New York University College of Dentistry for removal of severe, dark brown fluorosis staining on his anterior teeth. To remove the stain, the treating clinician used a microabrasive material, which leaves enamel intact, instead of a tooth-whitening agent, which requires removal of all affected enamel. To demonstrate that enamel structure is not disturbed by the microabrasive material, the authors performed a study using scanning electron microscopy, or SEM. They viewed enamel structure under SEM at x1,000 magnification. They viewed untreated microabraded enamel and compared it with enamel that had been treated for 20 seconds with 37 percent phosphoric acid. An etch pattern was not discernible on the tooth treated with the microabrasive material. The enamel prisms remained intact and the cores were not exposed. Microabrasion removes intrinsic fluorosis stain effectively while protecting enamel. In this case, an enamel shade of brown not in the range of any tooth color shade guide was reduced.

Method of recovering hazardous waste from phenolic resin filters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meikrantz, D.H.; Bourne, G.L.; McFee, J.N.

1990-12-31

A method has been found for treating phenolic resin filter, whereby the filter is solubilized within the filter cartridge housing so the filter material can be removed from the cartridge housing in a remote manner. The invention consists of contacting the filter within the housing with an aqueous solution of about 8 to 12M nitric acid, at a temperature from about 110 to 190{degree}F, maintaining the contact for a period of time sufficient to solubilize the phenolic material within the housing, and removing the solubilized phenolic material from the housing, thereby removing the filter cartridge from the housing. Any hazardousmore » or other waste material can then be separated from the filter material by chemical or other means.« less

Preferentially etched epitaxial liftoff of InP material

NASA Technical Reports Server (NTRS)

Bailey, Sheila G. (Inventor); Wilt, David M. (Inventor); Deangelo, Frank L. (Inventor)

1995-01-01

The present invention is directed toward a method of removing epitaxial substrates from host substrates. A sacrificial release layer of ternary material is placed on the substrate. A layer of InP is then placed on the ternary material. Afterward a layer of wax is applied to the InP layer to apply compressive force and an etchant material is used to remove the sacrificial release layer.

Preferentially Etched Epitaxial Liftoff of InP Material

NASA Technical Reports Server (NTRS)

Bailey, Sheila G. (Inventor); Wilt, David M. (Inventor); DeAngelo, Frank L. (Inventor)

1997-01-01

The present invention is directed toward a method of removing epitaxial substrates from host substrates. A sacrificial release layer of ternary material is placed on the substrate. A layer of InP is then placed on the ternary material. Afterward a layer of wax is applied to the InP layer to apply compressive force and an etchant material is used to remove the sacrificial release layer.

Investigations into the mechanism of material removal and surface modification at atomic scale on stainless steel using molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Ranjan, Prabhat; Balasubramaniam, R.; Jain, V. K.

2018-06-01

A molecular dynamics simulation (MDS) has been carried out to investigate the material removal phenomenon of chemo-mechanical magnetorheological finishing (CMMRF) process. To understand the role of chemical assisted mechanical abrasion in CMMRF process, material removal phenomenon is subdivided into three different stages. In the first stage, new atomic bonds viz. Fe-O-Si is created on the surface of the workpiece (stainless steel). The second stage deals with the rupture of parent bonds like Fe-Fe on the workpiece. In the final stage, removal of material from the surface in the form of dislodged debris (cluster of atoms) takes place. Effects of process parameters like abrasive particles, depth of penetration and initial surface condition on finishing force, potential energy (towards secondary phenomenon such as chemical instability of the finished surface) and material removal at atomic scale have been investigated. It was observed that the type of abrasive particle is one of the important parameters to produce atomically smooth surface. Experiments were also conducted as per the MDS to generate defect-free and sub-nanometre-level finished surface (Ra value better than 0.2 nm). The experimental results reasonably agree well with the simulation results.

General purpose rocket furnace

NASA Technical Reports Server (NTRS)

Aldrich, B. R.; Whitt, W. D. (Inventor)

1979-01-01

A multipurpose furnace for space vehicles used for material processing experiments in an outer space environment is described. The furnace contains three separate cavities designed to process samples of the widest possible range of materials and thermal requirements. Each cavity contains three heating elements capable of independent function under the direction of an automatic and programmable control system. A heat removable mechanism is also provided for each cavity which operates in conjunction with the control system for establishing an isothermally heated cavity or a wide range of thermal gradients and cool down rates. A monitoring system compatible with the rocket telemetry provides furnace performance and sample growth rate data throughout the processing cycle.

Alternatives to amputation.

PubMed Central

Lendrum, J.

1980-01-01

Alternatives to conventional skin flap cover for limb wounds extend both the number and type of defects which can now be closed with reconstruction of both form and function for patients who might otherwise come to amputation. The old adage that where a sinus leads to dead or foreign material it can only be closed after removal of that dead or foreign material is no longer true. The number of patients coming to above-knee amputation after prosthetic replacement of the knee joint could be reduced by muscle flap cover of exposed arthroplasty prostheses. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:7377695

Increasing spin crossover cooperativity in 2D Hofmann-type materials with guest molecule removal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zenere, Katrina A.; Duyker, Samuel G.; Trzop, Elzbieta

Ambient temperature spin crossover with wide hysteresis has been achieved in 2D Hofmann-type materials, where removal of guest molecules optimises ligand–ligand interactions, resulting in increased cooperativity.

Increasing spin crossover cooperativity in 2D Hofmann-type materials with guest molecule removal

DOE PAGES

Zenere, Katrina A.; Duyker, Samuel G.; Trzop, Elzbieta; ...

2018-01-01

Ambient temperature spin crossover with wide hysteresis has been achieved in 2D Hofmann-type materials, where removal of guest molecules optimises ligand–ligand interactions, resulting in increased cooperativity.

30 CFR 717.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2012 CFR

2012-07-01

... at least 3 feet to avoid overtopping by wind and wave action. (iii) Dams shall have minimum safety... pressures, internal erosion, sloughing, removal of material by solution, or erosion of material by loss into... regulatory authority before construction begins. (8) All dams shall be removed and the disturbed areas...

30 CFR 717.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2014 CFR

2014-07-01

... at least 3 feet to avoid overtopping by wind and wave action. (iii) Dams shall have minimum safety... pressures, internal erosion, sloughing, removal of material by solution, or erosion of material by loss into... regulatory authority before construction begins. (8) All dams shall be removed and the disturbed areas...

30 CFR 717.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2013 CFR

2013-07-01

... at least 3 feet to avoid overtopping by wind and wave action. (iii) Dams shall have minimum safety... pressures, internal erosion, sloughing, removal of material by solution, or erosion of material by loss into... regulatory authority before construction begins. (8) All dams shall be removed and the disturbed areas...

25 CFR 247.18 - What are the sanitation prohibitions?

Code of Federal Regulations, 2014 CFR

2014-04-01

..., bottle, sewage, waste water or material, either by removal from the site, or by depositing it into receptacles or at places provided for such purposes. (c) You may not bring refuse, debris, or toxic or hazardous materials to the sites for disposal. (d) All toxic or hazardous materials must be properly removed...

25 CFR 247.18 - What are the sanitation prohibitions?

Code of Federal Regulations, 2013 CFR

2013-04-01

..., bottle, sewage, waste water or material, either by removal from the site, or by depositing it into receptacles or at places provided for such purposes. (c) You may not bring refuse, debris, or toxic or hazardous materials to the sites for disposal. (d) All toxic or hazardous materials must be properly removed...

25 CFR 247.18 - What are the sanitation prohibitions?

Code of Federal Regulations, 2012 CFR

2012-04-01

..., bottle, sewage, waste water or material, either by removal from the site, or by depositing it into receptacles or at places provided for such purposes. (c) You may not bring refuse, debris, or toxic or hazardous materials to the sites for disposal. (d) All toxic or hazardous materials must be properly removed...

Robotic Water Blast Cleaner

NASA Technical Reports Server (NTRS)

Sharpe, M. H.; Roberts, M. L.; Hill, W. E.; Jackson, C. H.

1983-01-01

Water blasting system under development removes hard, dense, extraneous material from surfaces. High pressure pump forces water at supersonic speed through nozzle manipulated by robot. Impact of water blasts away unwanted material from workpiece rotated on air bearing turntable. Designed for removing thermal-protection material, system is adaptable to such industrial processes as cleaning iron or steel castings.

Indigenous Construction Materials for Theater Facilities

DTIC Science & Technology

2013-09-01

pebbles removed. Mortars are used to accommodate ir - regularities in size, shape, and surface of blocks, and it keeps all gaps be- tween CEBs closed to...distance in southeast Ethiopia. • Dryer and hotter than other sites in the country, with an average daily temperature exceeding 28 °C, but...purportedly available at http://www.goss-online.org, but the link was not functional as of 8 July 2013. A web search has returned some evidence that

Radioactive cobalt removal from Salem liquid radwaste with cobalt selective media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maza R.; Wilson, J.A.; Hetherington, R.

This paper reports results of benchtop tests using ion exchange material to selectively remove radioactive cobalt from high conductivity liquid radwaste at the Salem Nuclear Generating Station. The purpose of this test program is to reduce the number of curies in liquid releases without increasing the solid waste volume. These tests have identified two cobalt selective materials that together remove radioactive cobalt more effectively than the single component currently used. All test materials were preconditioned by conversion to the divalent calcium or sulfate form to simulate chemically exhausted media.

SEMICONDUCTOR TECHNOLOGY: Material removal rate in chemical-mechanical polishing of wafers based on particle trajectories

NASA Astrophysics Data System (ADS)

Jianxiu, Su; Xiqu, Chen; Jiaxi, Du; Renke, Kang

2010-05-01

Distribution forms of abrasives in the chemical mechanical polishing (CMP) process are analyzed based on experimental results. Then the relationships between the wafer, the abrasive and the polishing pad are analyzed based on kinematics and contact mechanics. According to the track length of abrasives on the wafer surface, the relationships between the material removal rate and the polishing velocity are obtained. The analysis results are in accord with the experimental results. The conclusion provides a theoretical guide for further understanding the material removal mechanism of wafers in CMP.

Optimal conditions for preparation of banana peels, sugarcane bagasse and watermelon rind in removing copper from water.

PubMed

Liu, Cong; Ngo, Huu Hao; Guo, Wenshan; Tung, Kuo-Lun

2012-09-01

In this study, three agro-waste materials were used as biosorbents for removal of copper (Cu) from water. This work aims to optimise conditions for preparation of these materials to obtain maximum Cu adsorption capacity. The optimal conditions were determined in terms of Cu removal efficiency and/or energy consumption. The results indicate that banana peels dried at 120°C for 2h and ground into powder form led to a better performance in terms of both copper removal efficiency and energy consumption. For sugarcane bagasse and watermelon rind, 120°C was the suitable drying temperature. However, the best drying time was 1h for sugarcane bagasse and 3h for watermelon rind. The powder form with size of <150 μm was optimal for all biosorbents in terms of removal efficiency and equilibration time. The findings are beneficial to the application of these agro-waste materials for Cu removal from water and wastewater treatment. Copyright © 2012. Published by Elsevier Ltd.

Fluorescent and Magnetic Mesoporous Hybrid Material: A Chemical and Biological Nanosensor for Hg2+ Ions

PubMed Central

Suresh, Moorthy; Anand, Chokkalingam; Frith, Jessica E.; Dhawale, Dattatray S.; Subramaniam, Vishnu P.; Strounina, Ekaterina; Sathish, Clastinrusselraj I.; Yamaura, Kazunari; Cooper-White, Justin J.; Vinu, Ajayan

2016-01-01

We introduce “sense, track and separate” approach for the removal of Hg2+ ion from aqueous media using highly ordered and magnetic mesoporous ferrosilicate nanocages functionalised with rhodamine fluorophore derivative. These functionalised materials offer both fluorescent and magnetic properties in a single system which help not only to selectively sense the Hg2+ ions with a high precision but also adsorb and separate a significant amount of Hg2+ ion in aqueous media. We demonstrate that the magnetic affinity of these materials, generated from the ultrafine γ-Fe2O3 nanoparticles present inside the nanochannels of the support, can efficiently be used as a fluorescent tag to sense the Hg2+ ions present in NIH3T3 fibroblasts live cells and to track the movement of the cells by external magnetic field monitored using confocal fluorescence microscopy. This simple approach of introducing multiple functions in the magnetic mesoporous materials raise the prospect of creating new advanced functional materials by fusing organic, inorganic and biomolecules to create advanced hybrid nanoporous materials which have a potential use not only for sensing and the separation of toxic metal ions but also for cell tracking in bio-separation and the drug delivery. PMID:26911660

The impact of loading approach and biological activity on NOM removal by ion exchange resins.

PubMed

Winter, Joerg; Wray, Heather E; Schulz, Martin; Vortisch, Roman; Barbeau, Benoit; Bérubé, Pierre R

2018-05-01

The present study investigated the impact of different loading approaches and microbial activity on the Natural Organic Matter (NOM) removal efficiency and capacity of ion exchange resins. Gaining further knowledge on the impact of loading approaches is of relevance because laboratory-scale multiple loading tests (MLTs) have been introduced as a simpler and faster alternative to column tests for predicting the performance of IEX, but only anecdotal evidence exists to support their ability to forecast contaminant removal and runtime until breakthrough of IEX systems. The overall trends observed for the removal and the time to breakthrough of organic material estimated using MLTs differed from those estimated using column tests. The results nonetheless suggest that MLTs could best be used as an effective tool to screen different ion exchange resins in terms of their ability to remove various contaminants of interest from different raw waters. The microbial activity was also observed to impact the removal and time to breakthrough. In the absence of regeneration, a microbial community rapidly established itself in ion exchange columns and contributed to the removal of organic material. Biological ion exchange (BIEX) removed more organic material and enabled operation beyond the point when the resin capacity would have otherwise been exhausted using conventional (i.e. in the absence of a microbial community) ion exchange. Furthermore, significantly greater removal of organic matter could be achieved with BIEX than biological activated carbon (BAC) (i.e. 56 ± 7% vs. 15 ± 5%, respectively) when operated at similar loading rates. The results suggest that for some raw waters, BIEX could replace BAC as the technology of choice for the removal of organic material. Copyright © 2018 Elsevier Ltd. All rights reserved.

Additives in fibers and fabrics.

PubMed

Barker, R H

1975-06-01

The additives and contaminants which occur in textile fibers vary widely, depending on the type of fiber and the pretreatment which it has received. Synthetic fibers such as nylon and polyester contain trace amounts of contaminants such as catalysts and catalyst deactivators which remain after the synthesis of the basic polymers. In addition, there are frequently a number of materials which are added to perform specific functions in almost all man-made fibers. Examples of these would include traces of metals or metal salts used as tracers for identification of specific lots of fiber, TiO2 or similar materials added as delustrants, and a host of organic species added for such special purposes as antistatic agents or flame retardants. There may also be considerable quantities of residual monomer or small oligomers dissolved in the polymer matrix. The situation becomes even more complex after the fibers are converted into fabric form. Numerous materials are applied at various stages of fabric preparation to act as lubricants, sizing agents, antistats, bleaches, and wetting agents to facilitate the processing, but these are normally removed before the fabric reaches the cutters of the ultimate consumers and therefore usually do not constitute potential hazards. However, there are many other chemical agents which are frequently added during the later stages of fabric preparation and which are not designed to be removed. Aside from dyes and printing pigments, the most common additive for apparel fabrics is a durable press treatment. This generally involves the use of materials capable of crosslinking cellulosics by reacting through such functions as N-methylolated amides or related compounds such as ureas and carbamates. These materials pose some potential hazards due to both the nitrogenous bases and the formaldehyde which they usually release. There is usually also some residual catalyst in fabrics which have received such treatments. Other types of chemical treatments which are often applied to fabrics to achieve special effects include flame retardants, soil release agents, antistatic agents, softeners, water and/or oil repellents, ultraviolet absorbers, bacteriostats, and fungistats.

Podoplanin immunopositive lymphatic vessels at the implant interface in a rat model of osteoporotic fractures.

PubMed

Lips, Katrin Susanne; Kauschke, Vivien; Hartmann, Sonja; Thormann, Ulrich; Ray, Seemun; Kampschulte, Marian; Langheinrich, Alexander; Schumacher, Matthias; Gelinsky, Michael; Heinemann, Sascha; Hanke, Thomas; Kautz, Armin R; Schnabelrauch, Matthias; Schnettler, Reinhard; Heiss, Christian; Alt, Volker; Kilian, Olaf

2013-01-01

Insertion of bone substitution materials accelerates healing of osteoporotic fractures. Biodegradable materials are preferred for application in osteoporotic patients to avoid a second surgery for implant replacement. Degraded implant fragments are often absorbed by macrophages that are removed from the fracture side via passage through veins or lymphatic vessels. We investigated if lymphatic vessels occur in osteoporotic bone defects and whether they are regulated by the use of different materials. To address this issue osteoporosis was induced in rats using the classical method of bilateral ovariectomy and additional calcium and vitamin deficient diet. In addition, wedge-shaped defects of 3, 4, or 5 mm were generated in the distal metaphyseal area of femur via osteotomy. The 4 mm defects were subsequently used for implantation studies where bone substitution materials of calcium phosphate cement, composites of collagen and silica, and iron foams with interconnecting pores were inserted. Different materials were partly additionally functionalized by strontium or bisphosphonate whose positive effects in osteoporosis treatment are well known. The lymphatic vessels were identified by immunohistochemistry using an antibody against podoplanin. Podoplanin immunopositive lymphatic vessels were detected in the granulation tissue filling the fracture gap, surrounding the implant and growing into the iron foam through its interconnected pores. Significant more lymphatic capillaries were counted at the implant interface of composite, strontium and bisphosphonate functionalized iron foam. A significant increase was also observed in the number of lymphatics situated in the pores of strontium coated iron foam. In conclusion, our results indicate the occurrence of lymphatic vessels in osteoporotic bone. Our results show that lymphatic vessels are localized at the implant interface and in the fracture gap where they might be involved in the removal of lymphocytes, macrophages, debris and the implants degradation products. Therefore the lymphatic vessels are involved in implant integration and fracture healing.

Podoplanin Immunopositive Lymphatic Vessels at the Implant Interface in a Rat Model of Osteoporotic Fractures

PubMed Central

Lips, Katrin Susanne; Kauschke, Vivien; Hartmann, Sonja; Thormann, Ulrich; Ray, Seemun; Kampschulte, Marian; Langheinrich, Alexander; Schumacher, Matthias; Gelinsky, Michael; Heinemann, Sascha; Hanke, Thomas; Kautz, Armin R.; Schnabelrauch, Matthias; Schnettler, Reinhard; Heiss, Christian; Alt, Volker; Kilian, Olaf

2013-01-01

Insertion of bone substitution materials accelerates healing of osteoporotic fractures. Biodegradable materials are preferred for application in osteoporotic patients to avoid a second surgery for implant replacement. Degraded implant fragments are often absorbed by macrophages that are removed from the fracture side via passage through veins or lymphatic vessels. We investigated if lymphatic vessels occur in osteoporotic bone defects and whether they are regulated by the use of different materials. To address this issue osteoporosis was induced in rats using the classical method of bilateral ovariectomy and additional calcium and vitamin deficient diet. In addition, wedge-shaped defects of 3, 4, or 5 mm were generated in the distal metaphyseal area of femur via osteotomy. The 4 mm defects were subsequently used for implantation studies where bone substitution materials of calcium phosphate cement, composites of collagen and silica, and iron foams with interconnecting pores were inserted. Different materials were partly additionally functionalized by strontium or bisphosphonate whose positive effects in osteoporosis treatment are well known. The lymphatic vessels were identified by immunohistochemistry using an antibody against podoplanin. Podoplanin immunopositive lymphatic vessels were detected in the granulation tissue filling the fracture gap, surrounding the implant and growing into the iron foam through its interconnected pores. Significant more lymphatic capillaries were counted at the implant interface of composite, strontium and bisphosphonate functionalized iron foam. A significant increase was also observed in the number of lymphatics situated in the pores of strontium coated iron foam. In conclusion, our results indicate the occurrence of lymphatic vessels in osteoporotic bone. Our results show that lymphatic vessels are localized at the implant interface and in the fracture gap where they might be involved in the removal of lymphocytes, macrophages, debris and the implants degradation products. Therefore the lymphatic vessels are involved in implant integration and fracture healing. PMID:24130867

Method of upgrading oils containing hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline

DOEpatents

Baker, Eddie G.; Elliott, Douglas C.

1993-01-01

The present invention is a multi-stepped method of converting an oil which is produced by various biomass and coal conversion processes and contains primarily single and multiple ring hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline. The single and multiple ring hydroxyaromatic hydrocarbon compounds in a raw oil material are first deoxygenated to produce a deoxygenated oil material containing single and multiple ring aromatic compounds. Then, water is removed from the deoxygenated oil material. The next step is distillation to remove the single ring aromatic compouns as gasoline. In the third step, the multiple ring aromatics remaining in the deoxygenated oil material are cracked in the presence of hydrogen to produce a cracked oil material containing single ring aromatic compounds. Finally, the cracked oil material is then distilled to remove the single ring aromatics as gasoline.

Method of upgrading oils containing hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline

DOEpatents

Baker, E.G.; Elliott, D.C.

1993-01-19

The present invention is a multi-stepped method of converting an oil which is produced by various biomass and coal conversion processes and contains primarily single and multiple ring hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline. The single and multiple ring hydroxyaromatic hydrocarbon compounds in a raw oil material are first deoxygenated to produce a deoxygenated oil material containing single and multiple ring aromatic compounds. Then, water is removed from the deoxygenated oil material. The next step is distillation to remove the single ring aromatic compounds as gasoline. In the third step, the multiple ring aromatics remaining in the deoxygenated oil material are cracked in the presence of hydrogen to produce a cracked oil material containing single ring aromatic compounds. Finally, the cracked oil material is then distilled to remove the single ring aromatics as gasoline.

Comparison of filter media materials for heavy metal removal from urban stormwater runoff using biofiltration systems.

PubMed

Lim, H S; Lim, W; Hu, J Y; Ziegler, A; Ong, S L

2015-01-01

The filter media in biofiltration systems play an important role in removing potentially harmful pollutants from urban stormwater runoff. This study compares the heavy metal removal potential (Cu, Zn, Cd, Pb) of five materials (potting soil, compost, coconut coir, sludge and a commercial mix) using laboratory columns. Total/dissolved organic carbon (TOC/DOC) was also analysed because some of the test materials had high carbon content which affects heavy metal uptake/release. Potting soil and the commercial mix offered the best metal uptake when dosed with low (Cu: 44.78 μg/L, Zn: 436.4 μg/L, Cd, 1.82 μg/L, Pb: 51.32 μg/L) and high concentrations of heavy metals (Cu: 241 μg/L, Zn: 1127 μg/L, Cd: 4.57 μg/L, Pb: 90.25 μg/L). Compost and sludge also had high removal efficiencies (>90%). Heavy metal leaching from these materials was negligible. A one-month dry period between dosing experiments did not affect metal removal efficiencies. TOC concentrations from all materials increased after the dry period. Heavy metal removal was not affected by filter media depth (600 mm vs. 300 mm). Heavy metals tended to accumulate at the upper 5 cm of the filter media although potting soil showed bottom-enriched concentrations. We recommend using potting soil as the principal media mixed with compost or sludge since these materials perform well and are readily available. The use of renewable materials commonly found in Singapore supports a sustainable approach to urban water management. Copyright © 2014 Elsevier Ltd. All rights reserved.

Efficacy of CM-Wire, M-Wire, and Nickel-Titanium Instruments for Removing Filling Material from Curved Root Canals: A Micro-Computed Tomography Study.

PubMed

Rodrigues, Clarissa Teles; Duarte, Marco Antonio Hungaro; de Almeida, Marcela Milanezi; de Andrade, Flaviana Bombarda; Bernardineli, Norberti

2016-11-01

The aim of this ex vivo study was to evaluate the removal of filling material after using CM-wire, M-wire, and nickel-titanium instruments in both reciprocating and rotary motions in curved canals. Thirty maxillary lateral incisors were divided into 9 groups according to retreatment procedures: Reciproc R25 followed by Mtwo 40/.04 and ProDesign Logic 50/.01 files; ProDesign R 25/.06 followed by ProDesign Logic 40/.05 and ProDesign Logic 50/.01 files; and Gates-Glidden drills, Hedström files, and K-files up to apical size 30 followed by K-file 40 and K-file 50 up to the working length. Micro-computed tomography scans were performed before and after each reinstrumentation procedure to evaluate root canal filling removal. Statistical analysis was performed with Kruskal-Wallis, Friedman, and Wilcoxon tests (P < .05). No significant differences in filling material removal were found in the 3 groups of teeth. The use of Mtwo and ProDesign Logic 40/.05 rotary files did not enhance filling material removal after the use of reciprocating files. The use of ProDesign Logic 50/.01 files significantly reduced the amount of filling material at the apical levels compared with the use of reciprocating files. Association of reciprocating and rotary files was capable of removing a large amount of filling material in the retreatment of curved canals, irrespective of the type of alloy of the instruments. The use of a ProDesign Logic 50/.01 file for apical preparation significantly reduced the amount of remnant material in the apical portion when compared with reciprocating instruments. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Investigation of argon ion sputtering on the secondary electron emission from gold samples

NASA Astrophysics Data System (ADS)

Yang, Jing; Cui, Wanzhao; Li, Yun; Xie, Guibai; Zhang, Na; Wang, Rui; Hu, Tiancun; Zhang, Hongtai

2016-09-01

Secondary electron (SE) yield, δ, is a very sensitive surface property. The values of δ often are not consistent for even identical materials. The influence of surface changes on the SE yield was investigated experimentally in this article. Argon ion sputtering was used to remove the contamination from the surface. Surface composition was monitored by X-ray photoelectron spectroscopy (XPS) and surface topography was scanned by scanning electron microscope (SEM) and atomic force microscope (AFM) before and after every sputtering. It was found that argon sputtering can remove contamination and roughen the surface. An ;equivalent work function; is presented in this thesis to establish the relationship between SE yield and surface properties. Argon ion sputtering of 1.5keV leads to a significant increase of so called ;work function; (from 3.7 eV to 6.0 eV), and a decrease of SE yield (from 2.01 to 1.54). These results provided a new insight into the influence of surface changes on the SE emission.

Soft-Templating Synthesis of Mesoporous Silica-Based Materials for Environmental Applications

NASA Astrophysics Data System (ADS)

Gunathilake, Chamila Asanka

Dissertation research is mainly focus on: 1) the development of mesoporous silica materials with organic pendant and bridging groups (isocyanurate, amidoxime, benzene) and incorporated metal (aluminum, zirconium, calcium, and magnesium) species for high temperature carbon dioxide (CO2) sorption, 2) phosphorous-hydroxy functionalized mesoporous silica materials for water treatment, and 3) amidoxime-modified ordered mesoporous silica materials for uranium sorption under seawater conditions. The goal is to design composite materials for environmental applications with desired porosity, surface area, and functionality by selecting proper metal oxide precursors, organosilanes, tetraethylorthosilicate, (TEOS), and block copolymer templates and by adjusting synthesis conditions. The first part of dissertation presents experimental studies on the merge of aluminum, zirconium, calcium, and magnesium oxides with mesoporous silica materials containing organic pendant (amidoxime) and bridging groups (isocyanurate, benzene) to obtain composite sorbents for CO2 sorption at ambient (0-25 °C) and elevated (60-120 °C) temperatures. These studies indicate that the aforementioned composite sorbents are fairly good for CO2 capture at 25 °C via physisorption mechanism and show a remarkably high affinity toward CO2 chemisorption at 60-120 °C. The second part of dissertation is devoted to silica-based materials with organic functionalities for removal of heavy metal ions such as lead from contaminated water and for recovery of metal ions such as uranium from seawater. First, ordered mesoporous organosilica (OMO) materials with diethylphosphatoethyl and hydroxyphosphatoethyl surface groups were examined for Pb2+ adsorption and showed unprecedented adsorption capacities up to 272 mg/g and 202 mg/g, respectively However, the amidoxime-modified OMO materials were explored for uranium extraction under seawater conditions and showed remarkable capacities reaching 57 mg of uranium per gram of adsorbent.

Orbital implants: State-of-the-art review with emphasis on biomaterials and recent advances.

PubMed

Baino, Francesco; Potestio, Isabel

2016-12-01

In the treatment of severe oculo-orbital traumas, intraocular malignancies or other life-threatening conditions it is sometimes necessary to surgically remove the patient's diseased eye. Following the removal of the eye, an orbital implant is inserted into the anophthalmic socket in order to provide satisfactory volume replacement and restore the aesthetic appearance of a normal eye. Over the last decades, the implant design and the criteria of materials selection evolved from simple non-porous polymeric sphere to devices with more complex shape and functionalities for ensuring better clinical outcomes in the long-term. Polymeric and ceramic porous implants have gained prominence since their highly interconnected porous architecture allows them to act as a passive framework for fibrovascular in-growth offering reduced complication rates and the possibility of pegging to enhance the motility of the artificial eye. However, there are still drawbacks to these materials. Some critical aspects of today's orbital implants include the risk of migration and extrusion, postoperative infections and low motility transmitted to the aesthetic ocular prosthesis. Hence, the development of novel biomaterials with enhanced functionalities (e.g. angiogenesis, antibacterial effect, in situ mouldability) which enable an improved outcome of eye replacement is more than ever desirable and represents one of the most challenging topics of research in the field of ocular implants. This review summarizes the evolution of orbital implants and provides an overview of the most recent advances in the field as well as some critical remarks for materials design, selection, characterization and translation to clinical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluating the biogas potential of the dry fraction from pretreatment of food waste from households.

PubMed

Murto, Marika; Björnsson, Lovisa; Rosqvist, Håkan; Bohn, Irene

2013-05-01

At the waste handling company NSR, Helsingborg, Sweden, the food waste fraction of source separated municipal solid waste is pretreated to obtain a liquid fraction, which is used for biogas production, and a dry fraction, which is at present incinerated. This pretreatment and separation is performed to remove impurities, however also some of the organic material is removed. The possibility of realising the methane potential of the dry fraction through batch-wise dry anaerobic digestion was investigated. The anaerobic digestion technique used was a two-stage process consisting of a static leach bed reactor and a methane reactor. Treatment of the dry fraction alone and in a mixture with structural material was tested to investigate the effect on the porosity of the leach bed. A tracer experiment was carried out to investigate the liquid flow through the leach beds, and this method proved useful in demonstrating a more homogenous flow through the leach bed when structural material was added. Addition of structural material to the dry fraction was needed to achieve a functional digestion process. A methane yield of 98 m3/ton was obtained from the dry fraction mixed with structural material after 76 days of digestion. This was in the same range as obtained in the laboratory scale biochemical methane potential test, showing that it was possible to extract the organic content in the dry fraction in this type of dry digestion system for the production of methane. Copyright © 2013 Elsevier Ltd. All rights reserved.

Method for net-shaping using aerogels

DOEpatents

Brinker, C. Jeffrey; Ashey, Carol S.; Reed, Scott T.; Sriram, Chunangad S.; Harris, Thomas M.

2001-01-01

A method of net-shaping using aerogel materials is provided by first forming a sol, aging the sol to form a gel, with the gel having a fluid component and having been formed into a medium selected from the group consisting of a powder, bulk material, or granular aerobeads, derivatizing the surface of the gel to render the surface unreactive toward further condensation, removing a portion of the fluid component of the final shaped gel to form a partially dried medium, placing the medium into a cavity, wherein the volume of said medium is less that the volume of the cavity, and removing a portion of the fluid component of the medium. The removal, such as by heating at a temperature of approximately less than 50.degree. C., applying a vacuum, or both, causes the volume of the medium to increase and to form a solid aerogel. The material can be easily removed by exposing the material to a solvent, thereby reducing the volume of the material. In another embodiment, the gel is derivatized and then formed into a shaped medium, where subsequent drying reduces the volume of the shaped medium, forming a net-shaping material. Upon further drying, the material increases in volume to fill a cavity. The present invention is both a method of net-shaping and the material produced by the method.

Submicron and Nanoparticulate Matter Removal by HEPA-Rated Media Filters and Packed Beds of Granular Materials

NASA Technical Reports Server (NTRS)

Perry, J. L.; Agui, J. H.; Vijayakimar, R

2016-01-01

Contaminants generated aboard crewed spacecraft by diverse sources consist of both gaseous chemical contaminants and particulate matter. Both HEPA media filters and packed beds of granular material, such as activated carbon, which are both commonly employed for cabin atmosphere purification purposes have efficacy for removing nanoparticulate contaminants from the cabin atmosphere. The phenomena associated with particulate matter removal by HEPA media filters and packed beds of granular material are reviewed relative to their efficacy for removing fine (less than 2.5 micrometers) and ultrafine (less than 0.01 micrometers) sized particulate matter. Considerations are discussed for using these methods in an appropriate configuration to provide the most effective performance for a broad range of particle sizes including nanoparticulates.

Isotherm and kinetics study of malachite green adsorption onto copper nanowires loaded on activated carbon: artificial neural network modeling and genetic algorithm optimization.

PubMed

Ghaedi, M; Shojaeipour, E; Ghaedi, A M; Sahraei, Reza

2015-05-05

In this study, copper nanowires loaded on activated carbon (Cu-NWs-AC) was used as novel efficient adsorbent for the removal of malachite green (MG) from aqueous solution. This new material was synthesized through simple protocol and its surface properties such as surface area, pore volume and functional groups were characterized with different techniques such XRD, BET and FESEM analysis. The relation between removal percentages with variables such as solution pH, adsorbent dosage (0.005, 0.01, 0.015, 0.02 and 0.1g), contact time (1-40min) and initial MG concentration (5, 10, 20, 70 and 100mg/L) was investigated and optimized. A three-layer artificial neural network (ANN) model was utilized to predict the malachite green dye removal (%) by Cu-NWs-AC following conduction of 248 experiments. When the training of the ANN was performed, the parameters of ANN model were as follows: linear transfer function (purelin) at output layer, Levenberg-Marquardt algorithm (LMA), and a tangent sigmoid transfer function (tansig) at the hidden layer with 11 neurons. The minimum mean squared error (MSE) of 0.0017 and coefficient of determination (R(2)) of 0.9658 were found for prediction and modeling of dye removal using testing data set. A good agreement between experimental data and predicted data using the ANN model was obtained. Fitting the experimental data on previously optimized condition confirm the suitability of Langmuir isotherm models for their explanation with maximum adsorption capacity of 434.8mg/g at 25°C. Kinetic studies at various adsorbent mass and initial MG concentration show that the MG maximum removal percentage was achieved within 20min. The adsorption of MG follows the pseudo-second-order with a combination of intraparticle diffusion model. Copyright © 2015 Elsevier B.V. All rights reserved.

Removal of mercury from an alumina refinery aqueous stream.

PubMed

Mullett, Mark; Tardio, James; Bhargava, Suresh; Dobbs, Charles

2007-06-01

Digestion condensate is formed as a by-product of the alumina refinery digestion process. The solution exhibits a high pH and is chemically reducing, containing many volatile species such as water, volatile organics, ammonia, and mercury. Because digestion condensate is chemically unique, an innovative approach was required to investigate mercury removal. The mercury capacity and adsorption kinetics were investigated using a number of materials including gold, silver and sulphur impregnated silica and a silver impregnated carbon. The results were compared to commercial sorbents, including extruded and powdered virgin activated carbons and a sulphur impregnated mineral. Nano-gold supported on silica (88% removal under batch conditions and 95% removal under flow conditions) and powdered activated carbon (91% under batch conditions and 98% removal under flow conditions) were the most effective materials investigated. The silver and sulphur impregnated materials were unstable in digestion condensate under the test conditions used.

Nano-adsorbents for the removal of metallic pollutants from water and wastewater.

PubMed

Sharma, Y C; Srivastava, V; Singh, V K; Kaul, S N; Weng, C H

2009-05-01

Of the variety of adsorbents available for the removal of heavy and toxic metals, activated carbon has been the most popular. A number of minerals, clays and waste materials have been regularly used for the removal of metallic pollutants from water and industrial effluents. Recently there has been emphasis on the application of nanoparticles and nanostructured materials as efficient and viable alternatives to activated carbon. Carbon nanotubes also have been proved effective alternatives for the removal of metallic pollutants from aqueous solutions. Because of their importance from an environmental viewpoint, special emphasis has been given to the removal of the metals Cr, Cd, Hg, Zn, As, and Cu. Separation of the used nanoparticles from aqueous solutions and the health aspects of the separated nanoparticles have also been discussed. A significant number of the latest articles have been critically scanned for the present review to give a vivid picture of these exotic materials for water remediation.

Preparation and performance study of MgFe2O4/metal-organic framework composite for rapid removal of organic dyes from water

NASA Astrophysics Data System (ADS)

Tian, Huairu; Peng, Jun; Lv, Tingting; Sun, Chen; He, Hua

2018-01-01

In present study, a stable and magnetic metal-organic framework (MOF) material was synthesized by simple solvothermal method as adsorbent to rapid removal of two organic dyes, the Rhodamine B (RB) and Rhodamine 6G (Rh6G), in water samples. The prepared material showed great characteristics of large surface area (519.86 m2 g-1), excellent magnetic responsivity (35.00 emu g-1) and rapid removal (within 5 min). Maximum adsorption capacities of the magnetic material toward RB and Rh6G were up to 219.78 and 306.75 mg g-1, respectively. Adsorption kinetics suggested the adsorption process met the pseudo-second-order kinetic model. The prepared material could be reused at least 10 times by washing with acetonitrile solution, the relative standard deviation (RSD) of these ten cycles removal efficiency was 4.8%. In conclusion, good chemical inertness, a mechanical/water stability and super-hydrophilicity feature made this MOF a promising adsorbent for targets removal from environmental water sample.

A numerical simulation on the flow of watershed filtration reactors using lignocellulosic materials

Treesearch

N. Hur; B. Choi; J.S. Han; E.W. Shin; S. Min; R.M. Rowell

2003-01-01

Pinyon juniper, a small-diameter and underutilized (SDU) lignocellulosic material, was harvested in New Mexico, identified as Juniperus monosperma at the USDA Forest Products Laboratory, chipped, fiberized and chemically modified to remove pollutants from wastewater. This juniper species was selected as a raw material through screening test for removal of pollutants...

Effect of naringin on hemodynamic changes and left ventricular function in renal artery occluded renovascular hypertension in rats

PubMed Central

Visnagri, Asjad; Adil, Mohammad; Kandhare, Amit D.; Bodhankar, Subhash L.

2015-01-01

Background: Renal artery occlusion (RAO) induced hypertension is a major health problem associated with structural and functional variations of the renal and cardiac vasculature. Naringin a flavanone glycoside derived possesses metal-chelating, antioxidant and free radical scavenging properties. Objective: The objective of this study was to investigate the antihypertensive activity of naringin in RAO induced hypertension in rats. Material and Methods: Male Wistar rats (180-200 g) were divided into five groups Sham, RAO, naringin (20, 40 and 80 mg/kg). Animals were pretreated with naringin (20, 40 and 80 mg/kg p.o) for 4 weeks. On the last day of the experiment, left renal artery was occluded with renal bulldog clamp for 4 h. After assessment of hemodynamic and left ventricular function various biochemical (superoxide dismutase [SOD], glutathione [GSH] and malondialdehyde [MDA]) and histological parameters were determined in the kidney. Results: RAO group significantly (P < 0.001) increased hemodynamic parameters at 15, 30 and 45 min of clamp removal. Naringin (40 and 80 mg/kg) treated groups showed a significant decrease in hemodynamic parameters at 15 min. after clamp removal that remained sustained for 60 min. Naringin (40 and 80 mg/kg) treated groups showed significant improvement in left ventricular function at 15, 30 and 45 min after clamp removal. Alteration in level of SOD, GSH and MDA was significantly restored by naringin (40 and 80 mg/kg) treatment. It also reduced histological aberration induced in kidney by RAO. Conclusion: It is concluded that the antihypertensive activity of naringin may result through inhibition of oxidative stress. PMID:25883516

Biphasic DC measurement approach for enhanced measurement stability and multi-channel sampling of self-sensing multi-functional structural materials doped with carbon-based additives

NASA Astrophysics Data System (ADS)

Downey, Austin; D'Alessandro, Antonella; Ubertini, Filippo; Laflamme, Simon; Geiger, Randall

2017-06-01

Investigation of multi-functional carbon-based self-sensing structural materials for structural health monitoring applications is a topic of growing interest. These materials are self-sensing in the sense that they can provide measurable electrical outputs corresponding to physical changes such as strain or induced damage. Nevertheless, the development of an appropriate measurement technique for such materials is yet to be achieved, as many results in the literature suggest that these materials exhibit a drift in their output when measured with direct current (DC) methods. In most of the cases, the electrical output is a resistance and the reported drift is an increase in resistance from the time the measurement starts due to material polarization. Alternating current methods seem more appropriate at eliminating the time drift. However, published results show they are not immune to drift. Moreover, the use of multiple impedance measurement devices (LCR meters) does not allow for the simultaneous multi-channel sampling of multi-sectioned self-sensing materials due to signal crosstalk. The capability to simultaneously monitor multiple sections of self-sensing structural materials is needed to deploy these multi-functional materials for structural health monitoring. Here, a biphasic DC measurement approach with a periodic measure/discharge cycle in the form of a square wave sensing current is used to provide consistent, stable resistance measurements for self-sensing structural materials. DC measurements are made during the measurement region of the square wave while material depolarization is obtained during the discharge region of the periodic signal. The proposed technique is experimentally shown to remove the signal drift in a carbon-based self-sensing cementitious material while providing simultaneous multi-channel measurements of a multi-sectioned self-sensing material. The application of the proposed electrical measurement technique appears promising for real-time utilization of self-sensing materials in structural health monitoring.

Liquid-assisted laser ablation of advanced ceramics and glass-ceramic materials

NASA Astrophysics Data System (ADS)

Garcia-Giron, A.; Sola, D.; Peña, J. I.

2016-02-01

In this work, results obtained by laser ablation of advanced ceramics and glass-ceramic materials assisted by liquids are reported. A Q-switched Nd:YAG laser at its fundamental wavelength of 1064 nm with pulse-width in the nanosecond range was used to machine the materials, which were immersed in water and ethylene glycol. Variation in geometrical parameters, morphology, and ablation yields were studied by using the same laser working conditions. It was observed that machined depth and removed volume depended on the thermal, optical, and mechanical features of the processed materials as well as on the properties of the surrounding medium in which the laser processing was carried out. Variation in ablation yields was studied in function of the liquid used to assist the laser process and related to refractive index and viscosity. Material features and working conditions were also related to the obtained results in order to correlate ablation parameters with respect to the hardness of the processed materials.

Influence of removing excess of resin-based materials applied to eroded enamel on the resistance to erosive challenge.

PubMed

Tereza, Guida Paola Genovez; de Oliveira, Gabriela Cristina; de Andrade Moreira Machado, Maria Aparecida; de Oliveira, Thais Marchine; da Silva, Thiago Cruvinel; Rios, Daniela

2016-04-01

The aim of this study was to evaluate the effect of removing excess of resin-based materials applied to eroded enamel, subjected to erosive challenge. Bovine enamel blocks were immersed in HCl 0.01M, pH 2.3, for 30s under agitation at 50 rpm in room temperature, in order to form a softened erosion lesion. The blocks were then randomly divided into eight groups (n=12) and treated as follows: Cn- and Ce-control without treatment, Hn- and He-fissure resin sealant (Helioseal Clear(®)), An- and Ae-self-etch adhesive (Adhese(®)), In- and Ie-infiltrant (Icon(®)); being n-with excess removal and e-without excess removal of the material. After application of the materials, the blocks were immersed in HCl for 2 min, followed by immersion in artificial saliva for 120 min. This cycle was repeated four times a day for five days. Material thickness and enamel wear were assessed using profilometry. Data were analyzed by two-way ANOVA and Tukey's test (P<0.05). Groups He, Ae, and Ie resulted in the formation of a layer of material over enamel, being similar effective in inhibiting erosion progression (P>0.05). Groups Hn, An, and In (with excess removal) were similar to controls (Cn, Ce) and resulted in near enamel loss after application and after erosive challenge (P>0.05). Resin-based materials are able to protect enamel against erosion only when they are present over enamel, as a physical barrier. The resin-based materials demonstrated potential to prevent the progression of erosion lesions when the material remains on the dental surface. Copyright © 2016 Elsevier Ltd. All rights reserved.

Drying of pulverized material with heated condensible vapor

DOEpatents

Carlson, Larry W.

1986-01-01

Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fins, on the outer lateral surface thereof. The cooled collection fins are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized material then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal.

Effects of the gap slope on the distribution of removal rate in Belt-MRF.

PubMed

Wang, Dekang; Hu, Haixiang; Li, Longxiang; Bai, Yang; Luo, Xiao; Xue, Donglin; Zhang, Xuejun

2017-10-30

Belt magnetorheological finishing (Belt-MRF) is a promising tool for large-optics processing. However, before using a spot, its shape should be designed and controlled by the polishing gap. Previous research revealed a remarkably nonlinear relationship between the removal function and normal pressure distribution. The pressure is nonlinearly related to the gap geometry, precluding prediction of the removal function given the polishing gap. Here, we used the concepts of gap slope and virtual ribbon to develop a model of removal profiles in Belt-MRF. Between the belt and the workpiece in the main polishing area, a gap which changes linearly along the flow direction was created using a flat-bottom magnet box. The pressure distribution and removal function were calculated. Simulations were consistent with experiments. Different removal functions, consistent with theoretical calculations, were obtained by adjusting the gap slope. This approach allows to predict removal functions in Belt-MRF.

Removal of nonylphenol from industrial sludge by using an electron beam

NASA Astrophysics Data System (ADS)

Choi, Jang-Seung; Park, Jun-Hyun; Kim, Yuri; Kim, JinKyu; Jung, SeungTae; Han, Bumsoo; Alkhuraiji, Turki S.

2016-09-01

Endocrine disrupting chemicals (EDCs) and potential EDCs are mostly man-made, found in various materials such as pesticides, additives or contaminants in food, and personal care products. EDCs have been suspected to be associated with altered reproductive function in males and females increased incidence of breast cancer, abnormal growth patterns and neuro-developmental delays in children and changes in immune function. A number of processes were investigated regarding their potential for removing of endocrine disrupters. Those processes are ferric chloride coagulation, powdered activated carbon, magnetic ion exchange combined with microfiltration or ultrafiltration, as well as nanofiltration, and reverse osmosis. They show some good removal of EDCs in aqueous solution, but do not show good efficiency when EDCs are in sludge. High energy ionizing radiation has the ability to remove the EDCs with a very high degree of reliability and in a clean and efficient manner. The ionizing radiation interacts with EDCs both directly and indirectly. Direct interaction takes place with EDCs, and the structure of EDCs is destroyed or changed. During indirect interaction, radiolysis products of water result in the formation of highly reactive intermediates which then react with the target molecules, culminating in structural changes. For confirmation of radiation reduction of EDCs in industrial sludge, a pilot scale experiment up to 50 kGy of electron beam was conducted with samples from the textile dyeing industries. The experimental result showed over a 90% reduction of nonylphenol (NP) at absorbed doses of around 10 kGy.

Use of different surface covering materials to enhance removal of radiocaesium in plants and upper soil from orchards in Fukushima prefecture.

PubMed

Sato, Mamoru; Akai, Hiroko; Saito, Yuichi; Takase, Tsugiko; Kikunaga, Hidetoshi; Sekiya, Nobuhito; Ohtsuki, Tsutomu; Yamaguchi, Katsuhiko

2017-04-04

The effectiveness of a decontamination methodology whereby herbaceous plants were grown through different materials covering the soil surface followed by subsequent removal of the material, associated plant tissues and attached soil on 137 Cs removal from soil was evaluated. Revegetation netting sown with Kentucky bluegrass and white clover had a high effectiveness in 137 Cs removal when rolling up the plants, roots, and rhizosphere soil approximately 6 months after sowing. The removal rate was lower when there was higher 137 Cs vertical migration down the soil profile. The maximum removal effectiveness of 93.1% was observed by rolling up fertilized Kentucky bluegrass with a well-developed root mat without netting, indicating that applying nutrients to encourage the development of roots or root mats in the 3 cm topsoil rhizosphere is an efficient technology to increase the decontamination effect of plant removal in orchards. Netting and weeding were able to remove up to 80% of 137 Cs in the soil without the use of heavy machinery. There was a significant relationship between the removal ratio and the removed soil weight per area. Using the relationship on the site below the canopy, removal of 14.3 kg m -2 DW soil would achieve a removal ratio of 80%. The effectiveness of the technique will decrease with time as radiocaesium migrates down the soil profile but this would be expected to occur slowly in many soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Disposable and removable nucleic acid extraction and purification cartridges for automated flow-through systems

DOEpatents

Regan, John Frederick

2014-09-09

Removable cartridges are used on automated flow-through systems for the purpose of extracting and purifying genetic material from complex matrices. Different types of cartridges are paired with specific automated protocols to concentrate, extract, and purifying pathogenic or human genetic material. Their flow-through nature allows large quantities sample to be processed. Matrices may be filtered using size exclusion and/or affinity filters to concentrate the pathogen of interest. Lysed material is ultimately passed through a filter to remove the insoluble material before the soluble genetic material is delivered past a silica-like membrane that binds the genetic material, where it is washed, dried, and eluted. Cartridges are inserted into the housing areas of flow-through automated instruments, which are equipped with sensors to ensure proper placement and usage of the cartridges. Properly inserted cartridges create fluid- and air-tight seals with the flow lines of an automated instrument.

Statistical Exposé of a Multiple-Compartment Anaerobic Reactor Treating Domestic Wastewater.

PubMed

Pfluger, Andrew R; Hahn, Martha J; Hering, Amanda S; Munakata-Marr, Junko; Figueroa, Linda

2018-06-01

  Mainstream anaerobic treatment of domestic wastewater is a promising energy-generating treatment strategy; however, such reactors operated in colder regions are not well characterized. Performance data from a pilot-scale, multiple-compartment anaerobic reactor taken over 786 days were subjected to comprehensive statistical analyses. Results suggest that chemical oxygen demand (COD) was a poor proxy for organics in anaerobic systems as oxygen demand from dissolved inorganic material, dissolved methane, and colloidal material influence dissolved and particulate COD measurements. Additionally, univariate and functional boxplots were useful in visualizing variability in contaminant concentrations and identifying statistical outliers. Further, significantly different dissolved organic removal and methane production was observed between operational years, suggesting that anaerobic reactor systems may not achieve steady-state performance within one year. Last, modeling multiple-compartment reactor systems will require data collected over at least two years to capture seasonal variations of the major anaerobic microbial functions occurring within each reactor compartment.

Robotic Waterblasting

NASA Technical Reports Server (NTRS)

2004-01-01

The Waterblast Research Cell supports development of automated systems that remove thermal protection materials and coatings from space flight hardware. These systems remove expended coatings without harsh chemicals or damaging underlying material. Potential applications of this technology include the removal of coatings from industrial machinery, aircraft, and other large structures. Use of the robot improves worker safety by reducing the exposure of persornel to high-pressure water. This technology is a proactive alternative to hazardous chemical strippers.

Removal of sulphur-containing odorants from fuel gases for fuel cell-based combined heat and power applications

NASA Astrophysics Data System (ADS)

de Wild, P. J.; Nyqvist, R. G.; de Bruijn, F. A.; Stobbe, E. R.

Natural gas (NG) and liquefied petroleum gas (LPG) are important potential feedstocks for the production of hydrogen for fuel cell-based (e.g. proton exchange membrane fuel cells (PEMFC) or solid oxide fuel Cells (SOFC) combined heat and power (CHP) applications. To prevent detrimental effects on the (electro)catalysts in fuel cell-based combined heat and power installations (FC-CHP), sulphur removal from the feedstock is mandatory. An experimental bench-marking study of adsorbents has identified several candidates for the removal of sulphur containing odorants at low temperature. Among these adsorbents a new material has been discovered that offers an economically attractive means to remove TetraHydroThiophene (THT), the main European odorant, from natural gas at ambient temperature. The material is environmentally benign, easy to use and possesses good activity (residual sulphur levels below 20 ppbv) and capacity for the common odorant THT in natural gas. When compared to state-of-the-art metal-promoted active carbon the new material has a THT uptake capacity that is up to 10 times larger, depending on temperature and pressure. Promoted versions of the new material have shown potential for the removal of THT at higher temperatures and/or for the removal of other odorants such as mercaptans from natural gas or from LPG.

15 CFR 922.166 - Permits other than for access to the Tortugas Ecological Reserve-application procedures and...

Code of Federal Regulations, 2014 CFR

2014-01-01

... activity will involve test excavations or removal of artifacts or materials for evaluative purposes, a... of the seabed and/or the removal of artifacts or other material necessary for evaluative purposes and...

15 CFR 922.166 - Permits other than for access to the Tortugas Ecological Reserve-application procedures and...

Code of Federal Regulations, 2011 CFR

2011-01-01

... activity will involve test excavations or removal of artifacts or materials for evaluative purposes, a... of the seabed and/or the removal of artifacts or other material necessary for evaluative purposes and...

15 CFR 922.166 - Permits other than for access to the Tortugas Ecological Reserve-application procedures and...

Code of Federal Regulations, 2013 CFR

2013-01-01

... activity will involve test excavations or removal of artifacts or materials for evaluative purposes, a... of the seabed and/or the removal of artifacts or other material necessary for evaluative purposes and...

15 CFR 922.166 - Permits other than for access to the Tortugas Ecological Reserve-application procedures and...

Code of Federal Regulations, 2012 CFR

2012-01-01

... activity will involve test excavations or removal of artifacts or materials for evaluative purposes, a... of the seabed and/or the removal of artifacts or other material necessary for evaluative purposes and...

15 CFR 922.166 - Permits other than for access to the Tortugas Ecological Reserve-application procedures and...

Code of Federal Regulations, 2010 CFR

2010-01-01

... activity will involve test excavations or removal of artifacts or materials for evaluative purposes, a... of the seabed and/or the removal of artifacts or other material necessary for evaluative purposes and...

Phosphate removal from agricultural drainage water using an iron oxyhydroxide filter material

USDA-ARS?s Scientific Manuscript database

Phosphate discharged with agricultural drainage causes water quality degradation on local, regional, and national scales. Iron oxyhydroxide filter materials can potentially remove the soluble phosphate present in drainage waters. Laboratory saturated column experiments and preliminary small-scale ...

Fine figure correction and other applications using novel MRF fluid designed for ultra-low roughness

NASA Astrophysics Data System (ADS)

Maloney, Chris; Oswald, Eric S.; Dumas, Paul

2015-10-01

An increasing number of technologies require ultra-low roughness (ULR) surfaces. Magnetorheological Finishing (MRF) is one of the options for meeting the roughness specifications for high-energy laser, EUV and X-ray applications. A novel MRF fluid, called C30, has been developed to finish surfaces to ULR. This novel MRF fluid is able to achieve <1.5Å RMS roughness on fused silica and other materials, but has a lower material removal rate with respect to other MRF fluids. As a result of these properties, C30 can also be used for applications in addition to finishing ULR surfaces. These applications include fine figure correction, figure correcting extremely soft materials and removing cosmetic defects. The effectiveness of these new applications is explored through experimental data. The low removal rate of C30 gives MRF the capability to fine figure correct low amplitude errors that are usually difficult to correct with higher removal rate fluids. The ability to figure correct extremely soft materials opens up MRF to a new realm of materials that are difficult to polish. C30 also offers the ability to remove cosmetic defects that often lead to failure during visual quality inspections. These new applications for C30 expand the niche in which MRF is typically used for.

A Targeted "Capture" and "Removal" Scavenger toward Multiple Pollutants for Water Remediation based on Molecular Recognition.

PubMed

Wang, Jie; Shen, Haijing; Hu, Xiaoxia; Li, Yan; Li, Zhihao; Xu, Jinfan; Song, Xiufeng; Zeng, Haibo; Yuan, Quan

2016-03-01

For the water remediation techniques based on adsorption, the long-standing contradictories between selectivity and multiple adsorbability, as well as between affinity and recyclability, have put it on weak defense amid more and more severe environment crisis. Here, a pollutant-targeting hydrogel scavenger is reported for water remediation with both high selectivity and multiple adsorbability for several pollutants, and with strong affinity and good recyclability through rationally integrating the advantages of multiple functional materials. In the scavenger, aptamers fold into binding pockets to accommodate the molecular structure of pollutants to afford perfect selectivity, and Janus nanoparticles with antibacterial function as well as anisotropic surfaces to immobilize multiple aptamers allow for simultaneously handling different kinds of pollutants. The scavenger exhibits high efficiencies in removing pollutants from water and it can be easily recycled for many times without significant loss of loading capacities. Moreover, the residual concentrations of each contaminant are well below the drinking water standards. Thermodynamic behavior of the adsorption process is investigated and the rate-controlling process is determined. Furthermore, a point of use device is constructed and it displays high efficiency in removing pollutants from environmental water. The scavenger exhibits great promise to be applied in the next generation of water purification systems.

A novel material detection algorithm based on 2D GMM-based power density function and image detail addition scheme in dual energy X-ray images.

PubMed

Pourghassem, Hossein

2012-01-01

Material detection is a vital need in dual energy X-ray luggage inspection systems at security of airport and strategic places. In this paper, a novel material detection algorithm based on statistical trainable models using 2-Dimensional power density function (PDF) of three material categories in dual energy X-ray images is proposed. In this algorithm, the PDF of each material category as a statistical model is estimated from transmission measurement values of low and high energy X-ray images by Gaussian Mixture Models (GMM). Material label of each pixel of object is determined based on dependency probability of its transmission measurement values in the low and high energy to PDF of three material categories (metallic, organic and mixed materials). The performance of material detection algorithm is improved by a maximum voting scheme in a neighborhood of image as a post-processing stage. Using two background removing and denoising stages, high and low energy X-ray images are enhanced as a pre-processing procedure. For improving the discrimination capability of the proposed material detection algorithm, the details of the low and high energy X-ray images are added to constructed color image which includes three colors (orange, blue and green) for representing the organic, metallic and mixed materials. The proposed algorithm is evaluated on real images that had been captured from a commercial dual energy X-ray luggage inspection system. The obtained results show that the proposed algorithm is effective and operative in detection of the metallic, organic and mixed materials with acceptable accuracy.

Adsorbent catalytic nanoparticles and methods of using the same

DOEpatents

Slowing, Igor Ivan; Kandel, Kapil

2017-01-31

The present invention provides an adsorbent catalytic nanoparticle including a mesoporous silica nanoparticle having at least one adsorbent functional group bound thereto. The adsorbent catalytic nanoparticle also includes at least one catalytic material. In various embodiments, the present invention provides methods of using and making the adsorbent catalytic nanoparticles. In some examples, the adsorbent catalytic nanoparticles can be used to selectively remove fatty acids from feedstocks for biodiesel, and to hydrotreat the separated fatty acids.

Ionization-induced annealing of pre-existing defects in silicon carbide

DOE PAGES

Zhang, Yanwen; Sachan, Ritesh; Pakarinen, Olli H.; ...

2015-08-12

A long-standing objective in materials research is to find innovative ways to remove preexisting damage and heal fabrication defects or environmentally induced defects in materials. Silicon carbide (SiC) is a fascinating wide-band gap semiconductor for high-temperature, high-power, high-frequency applications. Its high corrosion and radiation resistance makes it a key refractory/structural material with great potential for extremely harsh radiation environments. Here we show that the energy transferred to the electron system of SiC by energetic ions via inelastic ionization processes results in a highly localized thermal spike that can effectively heal preexisting defects and restore the structural order. This work revealsmore » an innovative self-healing process using highly ionizing ions, and it describes a critical aspect to be considered in modeling SiC performance as either a functional or a structural material for device applications or high-radiation environments.« less

Preparation, characterization and environmental/electrochemical energy storage testing of low-cost biochar from natural chitin obtained via pyrolysis at mild conditions

NASA Astrophysics Data System (ADS)

Magnacca, Giuliana; Guerretta, Federico; Vizintin, Alen; Benzi, Paola; Valsania, Maria C.; Nisticò, Roberto

2018-01-01

Chitin (a biopolymer obtained from shellfish industry) was used as precursor for the production of biochars obtained via pyrolysis treatments performed at mild conditions (in the 290-540 °C range). Biochars were physicochemical characterized in order to evaluate the pyrolysis-induced effects in terms of both functional groups and material structure. Moreover, such carbonaceous materials were tested as adsorbent substrates for the removal of target molecules from aqueous environment as well as in solid-gas experiments, to measure the adsorption capacities and selectivity toward CO2. Lastly, biochars were also investigated as possible cathode materials in sustainable and low-cost electrochemical energy storage devices, such as lithium-sulphur (Li-S) batteries. Interestingly, experimental results evidenced that such chitin-derived biochars obtained via pyrolysis at mild conditions are sustainable, low-cost and easy scalable alternative materials suitable for both environmental and energetic applications.

Towards AlN optical cladding layers for thermal management in hybrid lasers

NASA Astrophysics Data System (ADS)

Mathews, Ian; Lei, Shenghui; Nolan, Kevin; Levaufre, Guillaume; Shen, Alexandre; Duan, Guang-Hua; Corbett, Brian; Enright, Ryan

2015-06-01

Aluminium Nitride (AlN) is proposed as a dual function optical cladding and thermal spreading layer for hybrid ridge lasers, replacing current benzocyclobutene (BCB) encapsulation. A high thermal conductivity material placed in intimate contact with the Multi-Quantum Well active region of the laser allows rapid heat removal at source but places a number of constraints on material selection. AlN is considered the most suitable due to its high thermal conductivity when deposited at low deposition temperatures, similar co-efficient of thermal expansion to InP, its suitable refractive index and its dielectric nature. We have previously simulated the possible reduction in the thermal resistance of a hybrid ridge laser by replacing the BCB cladding material with a material of higher thermal conductivity of up to 319 W/mK. Towards this goal, we demonstrate AlN thin-films deposited by reactive DC magnetron sputtering on InP.

Adsorption-regeneration by heterogeneous Fenton process using modified carbon and clay materials for removal of indigo blue.

PubMed

Almazán-Sánchez, Perla Tatiana; Solache-Ríos, Marcos J; Linares-Hernández, Ivonne; Martínez-Miranda, Verónica

2016-01-01

Indigo blue dye is mainly used in dyeing of denim clothes and its presence in water bodies could have adverse effects on the aquatic system; for this reason, the objective of this study was to promote the removal of indigo blue dye from aqueous solutions by iron and copper electrochemically modified clay and activated carbon and the saturated materials were regenerated by a Fenton-like process. Montmorillonite clay was modified at pH 2 and 7; activated carbon at pH 2 and pH of the system. The elemental X-ray dispersive spectroscopy analysis showed that the optimum pH for modification of montmorillonite with iron and copper was 7 and for activated carbon was 2. The dye used in this work was characterized by infrared. Unmodified and modified clay samples showed the highest removal efficiencies of the dye (90-100%) in the pH interval from 2 to 10 whereas the removal efficiencies decrease as pH increases for samples modified at pH 2. Unmodified clay and copper-modified activated carbon at pH 2 were the most efficient activated materials for the removal of the dye. The adsorption kinetics data of all materials were best adjusted to the pseudo-second-order model, indicating a chemisorption mechanism and the adsorption isotherms data showed that the materials have a heterogeneous surface. The iron-modified clay could be regenerated by a photo-Fenton-like process through four adsorption-regeneration cycles, with 90% removal efficiency.

From harmful Microcystis blooms to multi-functional core-double-shell microsphere bio-hydrochar materials.

PubMed

Bi, Lei; Pan, Gang

2017-11-13

Harmful algal blooms (HABs) induced by eutrophication is becoming a serious global environmental problem affecting public health and aquatic ecological sustainability. A novel strategy for the utilization of biomass from HABs was developed by converting the algae cells into hollow mesoporous bio-hydrochar microspheres via hydrothermal carbonization method. The hollow microspheres were used as microreactors and carriers for constructing CaO 2 core-mesoporous shell-CaO 2 shell microspheres (OCRMs). The CaO 2 shells could quickly increase dissolved oxygen to extremely anaerobic water in the initial 40 min until the CaO 2 shells were consumed. The mesoporous shells continued to act as regulators restricting the release of oxygen from CaO 2 cores. The oxygen-release time using OCRMs was 7 times longer than when directly using CaO 2 . More interestingly, OCRMs presented a high phosphate removal efficiency (95.6%) and prevented the pH of the solution from rising to high levels in comparison with directly adding CaO 2 due to the OH - controlled-release effect of OCRMs. The distinct core-double-shell micro/nanostructure endowed the OCRMs with triple functions for oxygen controlled-release, phosphorus removal and less impact on water pH. The study is to explore the possibility to prepare smarter bio-hydrochar materials by utilizing algal blooms.

Calculating the optical properties of defects and surfaces in wide band gap materials

NASA Astrophysics Data System (ADS)

Deák, Peter

2018-04-01

The optical properties of a material critically depend on its defects, and understanding that requires substantial and accurate input from theory. This paper describes recent developments in the electronic structure theory of defects in wide band gap materials, where the standard local or semi-local approximations of density functional theory fail. The success of the HSE06 screened hybrid functional is analyzed in case of Group-IV semiconductors and TiO2, and shown that it is the consequence of error compensation between semi-local and non-local exchange, resulting in a proper derivative discontinuity (reproduction of the band gap) and a total energy which is a linear function of the fractional occupation numbers (removing most of the electron self-interaction). This allows the calculation of electronic transitions with accuracy unseen before, as demonstrated on the single-photon emitter NV(-) center in diamond and on polaronic states in TiO2. Having a reliable tool for electronic structure calculations, theory can contribute to the understanding of complicated cases of light-matter interaction. Two examples are considered here: surface termination effects on the blinking and bleaching of the light-emission of the NV(-) center in diamond, and on the efficiency of photocatalytic water-splitting by TiO2. Finally, an outlook is presented for the application of hybrid functionals in other materials, as, e.g., ZnO, Ga2O3 or CuGaS2.

Process for removing sulfur from coal

DOEpatents

Aida, Tetsuo; Squires, Thomas G.; Venier, Clifford G.

1985-02-05

A process for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

Interactions of 14C-labeled multi-walled carbon nanotubes with soil minerals in water.

PubMed

Zhang, Liwen; Petersen, Elijah J; Zhang, Wen; Chen, Yongsheng; Cabrera, Miguel; Huang, Qingguo

2012-07-01

Carbon nanotubes are often modified to be stable in the aqueous phase by adding extensive hydrophilic surface functional groups. The stability of such CNTs in water with soil or sediment is one critical factor controlling their environmental fate. We conducted a series of experiments to quantitatively assess the association between water dispersed multi-walled carbon nanotubes (MWCNTs) and three soil minerals (kaolinite, smectite, or shale) in aqueous solution under different sodium concentrations. (14)C-labeling was used in these experiments to unambiguously quantify MWCNTs. The results showed that increasing ionic strength strongly promoted the removal of MWCNTs from aqueous phase. The removal tendency is inversely correlated with the soil minerals' surface potential and directly correlated with their hydrophobicity. This removal can be interpreted by the extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory especially for kaolinite and smectite. Shale, which contains large and insoluble organic materials, sorbed MWCNTs the most strongly. Copyright © 2012 Elsevier Ltd. All rights reserved.

Stabilization of cartwheel-less centrioles for duplication requires CEP295-mediated centriole to centrosome conversion

PubMed Central

Izquierdo, Denisse; Wang, Won-Jing; Uryu, Kunihiro; Tsou, Meng-Fu Bryan

2014-01-01

SUMMARY Vertebrate centrioles lose their geometric scaffold, the cartwheel, during mitosis, concurrently with gaining the ability to recruit the pericentriolar material (PCM) and thereby function as the centrosome. Cartwheel removal has recently been implicated in centriole duplication, but whether “cartwheel-less” centrioles are intrinsically stable, or must be maintained through other modifications remains unclear. Here, we identify a newborn centriole-enriched protein, KIAA1731/CEP295, specifically mediating centriole-to-centrosome conversion but dispensable for cartwheel removal. In the absence of CEP295, centrioles form in S/G2 phase, and lose their associated cartwheel in mitosis, but cannot be converted to centrosomes, uncoupling the two events. Strikingly, centrioles devoid of both the PCM and cartwheel progressively lose centriolar components, whereas centrioles associating with either the cartwheel or PCM alone can exist stably. Thus, cartwheel removal can have grave repercussions to centriole stability, and centriole-to-centrosome conversion mediated by CEP295 must occur in parallel to maintain cartwheel-less centrioles for duplication. PMID:25131205

Effective Removal of Tetracycline Antibiotics from Water using Hybrid Carbon Membranes

NASA Astrophysics Data System (ADS)

Liu, Ming-Kai; Liu, Ying-Ya; Bao, Dan-Dan; Zhu, Gen; Yang, Guo-Hai; Geng, Jun-Feng; Li, Hai-Tao

2017-03-01

Antibiotic residues in drinking water have become a global problem, especially in developing countries. However, effective purification of water contaminated by antibiotics remains a great challenge. Here, we investigated the removing of tetracycline by carbon nanomaterials with different structures and surface functionalities. The result shows that a membrane of thick graphene oxide (GO) and activated carbon (AC) with a thickness of 15 μm can effectively remove 98.9% of tetracycline hydrochloride (TCH) from water by vacuum filtration. Structural analysis indicated that the AC nanoparticles were uniformly inserted into the GO interstitial sites without any aggregations. Also, GO sheets were loosened by the encapsulated AC nanoparticles, leading to the formation of numerous tiny pores (3-10 nm) that acted as channels for fluid passage, whereas the carbons and chemical groups on the GO surface adsorbed TCH. GO/AC membrane exhibits the best adsorption efficiency among the investigated materials, including pure GO, AC, carbon nanotube (CNT), and CNT/AC and GO/CNT hybrids.

Implant Supported Fixed Restorations versus Implant Supported Removable Overdentures: A Systematic Review

PubMed Central

Selim, Khaled; Ali, Sherif; Reda, Ahmed

2016-01-01

AIM: The aim of this study is to systematically evaluate and compare implant retained fixed restoration versus implant retained over denture. MATERIAL AND METHODS: Search was made in 2 databases including PubMed and PubMed Central. Title and abstract were screened to select studies comparing implant retained fixed restorations versus implant retained removable overdentures. Articles which did not follow the inclusion criteria were excluded. Included papers were then read carefully for a second stage filter, this was followed by manual searching of bibliography of selected articles. RESULTS: The search resulted in 5 included papers. One study evaluated the masticatory function, while the other 4 evaluated the patient satisfaction. Two of them used Visual Analogue Scale (VAS) as a measurement tool, while the other two used VAS and Categorical Scales (CAT). Stability, ability to chew, ability to clean, ability to speak and esthetics were the main outcomes of the 4 included papers. CONCLUSION: Conflicting results was observed between the fixed and removable restorations. PMID:28028423

Hibiscus rosa- sinensis leaf extract as coagulant aid in leachate treatment

NASA Astrophysics Data System (ADS)

Awang, Nik Azimatolakma; Aziz, Hamidi Abdul

2012-12-01

Hibiscus rosa- sinensis is a biodegradable material that has remained untested for flocculating properties. The objective of this study is to examine the efficiency of coagulation-flocculation processes for the removal of color, iron (Fe3+), suspended solids, turbidity and ammonia nitrogen(NH3-N), from landfill leachate using 4,000 mg/L alum in conjunction with H. rosa- sinensis leaf extract (HBaqs). Hydroxyl (O-H) and (carboxyl) C=O functional groups along the HBaqs chain help to indulge flocculating efficiency of HBaqs via bridging. The experiments confirm the positive coagulation properties of HBaqs. The Fe3+ removal rate using 4,000 mg/L alum as sole coagulant was approximately 60 %, and increased to 100 % when 4,000 mg/L alum was mixed with 500 mg/L HBaqs. By mixing, 4,000 mg/L alum with 100-500 mg/L HBaqs, 72 % of SS was removed as compared with only 45 % reduction using 4,000 mg/L alum as sole coagulant.

Removal of bacteriophages with different surface charges by diverse ceramic membrane materials in pilot spiking tests.

PubMed

Hambsch, B; Bösl, M; Eberhagen, I; Müller, U

2012-01-01

This study examines mechanisms for removal of bacteriophages (MS2 and phiX174) by ceramic membranes without application of flocculants. The ceramic membranes considered included ultra- and microfiltration membranes of different materials. Phages were spiked into the feed water in pilot scale tests in a waterworks. The membranes with pore sizes of 10 nm provided a 2.5-4.0 log removal of the phages. For pore sizes of 50 nm, the log removal dropped to 0.96-1.8. The membrane with a pore size of 200 nm did not remove phages. So, the removal of both MS2- and phiX174-phages depended on the pore size of the membranes. But apart from pore size also other factors influence the removal of phages. Removal was 0.5-0.9 log higher for MS2-phages compared with phiX174-phages. Size exclusion seems to be the major but not the only mechanism which influences the efficiency of phage removal by ceramic membranes.

Theoretical study on removal rate and surface roughness in grinding a RB-SiC mirror with a fixed abrasive.

PubMed

Wang, Xu; Zhang, Xuejun

2009-02-10

This paper is based on a microinteraction principle of fabricating a RB-SiC material with a fixed abrasive. The influence of the depth formed on a RB-SiC workpiece by a diamond abrasive on the material removal rate and the surface roughness of an optical component are quantitatively discussed. A mathematical model of the material removal rate and the simulation results of the surface roughness are achieved. In spite of some small difference between the experimental results and the theoretical anticipation, which is predictable, the actual removal rate matches the theoretical prediction very well. The fixed abrasive technology's characteristic of easy prediction is of great significance in the optical fabrication industry, so this brand-new fixed abrasive technology has wide application possibilities.

Electrolytic decontamination of conductive materials for hazardous waste management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wedman, D.E.; Martinez, H.E.; Nelson, T.O.

1996-12-31

Electrolytic removal of plutonium and americium from stainless steel and uranium surfaces has been demonstrated. Preliminary experiments were performed on the electrochemically based decontamination of type 304L stainless steel in sodium nitrate solutions to better understand the metal removal effects of varying cur-rent density, pH, and nitrate concentration parameters. Material removal rates and changes in surface morphology under these varying conditions are reported. Experimental results indicate that an electropolishing step before contamination removes surface roughness, thereby simplifying later electrolytic decontamination. Sodium nitrate based electrolytic decontamination produced the most uniform stripping of material at low to intermediate pH and at sodiummore » nitrate concentrations of 200 g L{sup -1} and higher. Stirring was also observed to increase the uniformity of the stripping process.« less

Crack propagation and the material removal mechanism of glass-ceramics by the scratch test.

PubMed

Qiu, Zhongjun; Liu, Congcong; Wang, Haorong; Yang, Xue; Fang, Fengzhou; Tang, Junjie

2016-12-01

To eliminate the negative effects of surface flaws and subsurface damage of glass-ceramics on clinical effectiveness, crack propagation and the material removal mechanism of glass-ceramics were studied by single and double scratch experiments conducted using an ultra-precision machine. A self-manufactured pyramid shaped single-grit tool with a small tip radius was used as the scratch tool. The surface and subsurface crack propagations and interactions, surface morphology and material removal mechanism were investigated. The experimental results showed that the propagation of lateral cracks to the surface and the interaction between the lateral cracks and radial cracks are the two main types of material peeling, and the increase of the scratch depth increases the propagation angle of the radial cracks and the interaction between the cracks. In the case of a double scratch, the propagation of lateral cracks and radial cracks between paired scratches results in material peeling. The interaction between adjacent scratches depends on the scratch depth and separation distance. There is a critical separation distance where the normalized material removal volume reaches its peak. These findings can help reduce surface flaws and subsurface damage induced by the grinding process and improve the clinical effectiveness of glass-ceramics used as biological substitute and repair materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

PAMAM dendrimers and graphene: Materials for removing aromatic contaminants from water

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeFever, Ryan S.; Geitner, Nicholas K.; Bhattacharya, Priyanka

2015-04-07

We present results from experiments and atomistic molecular dynamics simulations on the association of naphthalene with polyamidoamine (PAMAM) dendrimers and graphene oxide (GrO). Specifically, we investigate 3rd-6th generation (G3-G6) PAMAM dendrimers and GrO with different levels of oxidation. The work is motivated by the potential applications of these materials in removing polycyclic aromatic hydrocarbon contaminants from water. Our experimental results indicate that graphene oxide outperforms dendrimers in removing naphthalene from water. Molecular dynamics simulations suggest that the prominent factors driving naphthalene association to these seemingly disparate materials are similar. Interestingly, we find that cooperative interactions between the naphthalene molecules playmore » a significant role in enhancing their association to the dendrimers and graphene oxide. Our findings highlight that while selection of appropriate materials is important, the interactions between the contaminants themselves can also be important in governing the effectiveness of a given material. The combined use of experiments and molecular dynamics simulations allows us to comment on the possible factors resulting in better performance of graphene oxide in removing naphthalene from water.« less

First Principles Investigation of Li/Fe-Oxide as a High Energy Material for Hybrid All-in-One Li-ion/Li-O2 Batteries

NASA Astrophysics Data System (ADS)

Kinaci, Alper; Trahey, Lynn; Thackeray, Michael M.; Kirklin, Scott; Wolverton, Christopher; Chan, Maria K. Y.; CenterElectrical Energy Storage Collaboration

2014-03-01

We recently introduced a vision for high energy all-in-one electrode/electrocatalyst materials that can be used in hybrid Li-ion/Li-O2 (Li-air) cells. Recent experiments using Li5FeO4 demonstrated substantially smaller voltage polarizations and hence higher energy efficiency compared to standard Li-O2 cells forming Li2O2. The mechanism by which the charge process activates the Li5FeO4, however, is not well understood. Here, we present first principles density functional theory (DFT) calculations to establish the thermodynamic conditions for the extraction of Li/Li +O from Li5FeO4. A step-by-step, history-dependent, removal process has been followed and the stability of the Li and Li +O deficient samples is investigated on the basis of the energies of the extraction reactions. Various stages of Li/Li +O removal are identified, and structural changes and electronic structure evolution, as well as computed XRD, XANES, and PDF characterizations are reported.

Flexible and porous cellulose aerogels/zeolitic imidazolate framework (ZIF-8) hybrids for adsorption removal of Cr(IV) from water

NASA Astrophysics Data System (ADS)

Bo, Shaoguo; Ren, Wenjing; Lei, Chao; Xie, Yuanbo; Cai, Yurong; Wang, Shunli; Gao, Junkuo; Ni, Qingqing; Yao, Juming

2018-06-01

The low cost of adsorption treatment of heavy metal ions in water has been extensively studied. In this paper, we have demonstrated a facile method of combining two emerging materials cellulose aerogels (CA) and metal-organic frameworks (MOFs) into one highly functional aerogel to adsorption removal of heavy metal ions from water, by entrapping MOF particles into a flexible and porous CA. The resultant hybrid cellulose aerogels had a highly porous structure with zeolitic imidazolate framework-8 (ZIF-8) loadings can reach 30 wt%. The hybrid cellulose aerogels (named as ZIF-8@CA) show good adsorption capacity for Cr(Ⅵ). The adsorption process of ZIF-8@CA is better described by pseudo-second-order kinetic model and Langmuir isotherm, with maximum monolayer adsorption capacity of 41.8 mg g-1 for Cr(Ⅵ), whose adsorption capacity has greatly improved when compared with a single CA or ZIF-8. Thus, such a flexible and durable hybrid cellulose aerogel is a very prospective material for metal ions cleanup and industrial wastewater purification.

Development of a graphene oxide/chitosan nanocomposite for the removal of picric acid from aqueous solutions: Study of sorption parameters.

PubMed

Mohseni Kafshgari, Mona; Tahermansouri, Hasan

2017-12-01

The functionalization of graphene oxide (GO) with chitosan (Chi) has been investigated to prepare a nanocomposite material (GO-Chi) for the removal of picric acid from aqueous solutions. Materials were characterized by FT-IR, TGA, DTG, FESEM, EDX, XRD and BET. Batch experiments such as solution pH, amount of adsorbents, contact time, concentration of the picric acid and temperature were achieved to study sorption process. Kinetic studies were well described by pseudo-second-order kinetic model for both adsorbents. Isotherm studies showed that the Langmuir isotherm for GO and Freundlich and Halsey models for GO-Chi were found to best represent the measured sorption data. Negative ΔG° values for GO-Chi and positive ones for GO indicated the nature of spontaneous and unspontaneous, respectively for adsorption process. In addition, picric acid molecules can be desorbed from GO-Chi up to 80% at pH=9 and that the consumed GO-Chi could be reutilized up to 5th cycle of regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of PAA/PVDF-NZVI hybrids for metronidazole removal: synthesis, characterization, and reactivity characteristics.

PubMed

Yang, Jiacheng; Wang, Xiangyu; Zhu, Minping; Liu, Huiling; Ma, Jun

2014-01-15

For the first time, the removal process of metronidazole (MNZ) from aqueous solutions over nano zerovalent iron (NZVI) encapsulated within poly(acrylic acid) (PAA)/poly(vinylidene fluoride) (PVDF) membranes was reported. The resultant composite (PPN) demonstrated high reactivity, excellent stability and reusability over the reaction course. Such excellent performance might be attributed to the presence of the charged carboxyl groups in PVDF membrane support, which could enhance NZVI dispersion and improve its longevity. Results showed that a lower initial concentration and higher reaction temperature facilitated the removal of MNZ by PPN, and that the acidic and neutral conditions generally exhibited more favorable effect on MNZ removal than the alkaline ones. Kinetics of the MNZ removal by PPN was found to follow a two-parameter pseudo-first-order decay model well, and the activation energy of the MNZ degradation by PPN was determined to be 30.49kJ/mol. The presence of chloride ions slightly enhanced the reactivity of PPN with MNZ, whereas sulfate ions inhibited its reactivity. In addition, MNZ degradation pathways by PPN were proposed based on the identified intermediates. This study suggests that PPN composite possessing excellent performance may be a promising functional material to pretreat antibiotic wastewaters. Copyright © 2013 Elsevier B.V. All rights reserved.

Adsorbent for p-phenylenediamine adsorption and removal based on graphene oxide functionalized with magnetic cyclodextrin

NASA Astrophysics Data System (ADS)

Wang, Dongxue; Liu, Liangliang; Jiang, Xinyu; Yu, Jingang; Chen, Xiaohong; Chen, Xiaoqing

2015-02-01

Recently, graphene oxide (GO) based magnetic nanocomposites have been widely used in an adsorption-based process for the removal of organic pollutants from the water system. In this study, magnetic β-cyclodextrin-graphene oxide nanocomposites (MCG) were synthesized according to covalent binding of magnetic β-cyclodextrin nanoparticles onto the GO surface and the as-made nanocomposites were successfully applied as adsorbents for the adsorption and removal of p-phenylenediamines (PPD). The composition and morphology of prepared materials were characterized by Fourier infrared spectrometry (FT-IR), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Effects of pH, temperature, time and reusability on the adsorption of PPD were investigated, as well as the kinetics and isotherms parameters of the adsorbents were determined. The results indicated that the maximum adsorption capacity of MCG was 1102.58 mg/g at 45 °C and pH 8. The adsorption capacity remained at 81% after five cycles. Removal rate could reach 98% after three times of adsorption. The adsorption process with PPD was found that fitted pseudo-second-order kinetics equations and the Langmuir adsorption model. The results showed the MCG had a good adsorption ability to remove organic pollutants in wastewater.

29 CFR 1926.855 - Manual removal of floors.

Code of Federal Regulations, 2011 CFR

2011-07-01

... floor arch, debris and other material shall be removed from such arch and other adjacent floor area... collapse. The open space between planks shall not exceed 16 inches. (c) Safe walkways, not less than 18... cleared of debris and any other unnecessary materials. ...

29 CFR 1926.855 - Manual removal of floors.

Code of Federal Regulations, 2012 CFR

2012-07-01

... floor arch, debris and other material shall be removed from such arch and other adjacent floor area... collapse. The open space between planks shall not exceed 16 inches. (c) Safe walkways, not less than 18... cleared of debris and any other unnecessary materials. ...

29 CFR 1926.855 - Manual removal of floors.

Code of Federal Regulations, 2013 CFR

2013-07-01

... floor arch, debris and other material shall be removed from such arch and other adjacent floor area... collapse. The open space between planks shall not exceed 16 inches. (c) Safe walkways, not less than 18... cleared of debris and any other unnecessary materials. ...

29 CFR 1926.855 - Manual removal of floors.

Code of Federal Regulations, 2010 CFR

2010-07-01

... floor arch, debris and other material shall be removed from such arch and other adjacent floor area... collapse. The open space between planks shall not exceed 16 inches. (c) Safe walkways, not less than 18... cleared of debris and any other unnecessary materials. ...

29 CFR 1926.855 - Manual removal of floors.

Code of Federal Regulations, 2014 CFR

2014-07-01

... floor arch, debris and other material shall be removed from such arch and other adjacent floor area... collapse. The open space between planks shall not exceed 16 inches. (c) Safe walkways, not less than 18... cleared of debris and any other unnecessary materials. ...

13. Removal of slide material and construction of stone retaining ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Removal of slide material and construction of stone retaining wall to protect highway. Zion NP negative no. 2084. Photographer: Russell K. Grater, 1941. - Floor of the Valley Road, Between Zion-Mt. Carmel Highway & Temple of Sinawava, Springdale, Washington County, UT

Functionalized layered double hydroxide with nitrogen and sulfur co-decorated carbondots for highly selective and efficient removal of soft Hg2+ and Ag+ ions.

PubMed

Asiabi, Hamid; Yamini, Yadollah; Shamsayei, Maryam; Molaei, Karam; Shamsipur, Mojtaba

2018-05-28

A facile composite was fabricated via direct assembly of nitrogen and sulfur co-decorated carbon dots with abundant oxygen-containing functional groups on the surface of the positively charged layered double hydroxide (N,S-CDs-LDH). The novel N,S-CDs-LDH demonstrates highly selective bindings (M-S) and an extremely efficient removal capacity for soft metal ions such as Ag + and Hg 2+ ions. N,S-CDs-LDH displayed a selectivity order of Ag + > Hg 2+ > Cu 2+ > Pb 2+ > Zn 2+ > Cd 2+ for their adsorption. The enormous capacities for Hg 2+ (625.0 mg g -1 ) and Ag + (714.3 mg g -1 ) and very high distribution coefficients (K d ) of 9.9 × 10 6 mL g -1 (C 0  = 20 mg L -1 ) and 2.0 × 10 7 mL g -1 (C 0  = 20 mg L -1 ) for Hg 2+ and Ag + , respectively, place the N,S-CDs-LDH at the top of LDH based materials known for such removal. The adsorption kinetic curves for Hg 2+ and Ag + fitted well with the pseudo-second order model. For Hg 2+ and Ag + , an exceptionally rapid capture with removal ∼100% within 80 min was observed (C ions  = 30 mg L -1 and V/m ratio of 1000). The adsorption isotherms were well described using Langmuir isotherm. The N,S-CDs-LDH was successfully applied to highly efficient removal of Hg 2+ and Ag + from aqueous solutions. Copyright © 2018 Elsevier B.V. All rights reserved.

Electrostatic Assembly of Nanomaterials for Hybrid Electrodes and Supercapacitors

NASA Astrophysics Data System (ADS)

Hammond, Paula

2015-03-01

Electrostatic assembly methods have been used to generate a range of new materials systems of interest for electrochemical energy and storage applications. Over the past several years, it has been demonstrated that carbon nanotubes, metals, metal oxides, polymeric nanomaterials, and biotemplated materials systems can be incorporated into ultrathin films to generate supercapacitors and battery electrodes that illustrate significant energy density and power. The unique ability to control the incorporation of such a broad range of materials at the nanometer length scale allows tailoring of the final properties of these unique composite systems, as well as the capability of creating complex micron-scale to nanoporous morphologies based on the scale of the nanomaterial that is absorbed within the structure, or the conditions of self-assembly. Recently we have expanded these capabilities to achieve new electrodes that are templated atop electrospun polmer fiber scaffolds, in which the polymer can be selectively removed to achieve highly porous materials. Spray-layer-by-layer and filtration methods of functionalized multiwall carbon nanotubes and polyaniline nanofibers enable the generation of electrode systems with unusually high surface. Incorporation of psuedocapacitive nanoparticles can enhance capacitive properties, and other catalytic or metallic nanoparticles can be implemented to enhance electrochemical or catalytic function.

The electrical discharge machining of ceramics

NASA Astrophysics Data System (ADS)

Trueman, Christopher Stuart

This study introduces the concept of developing a novel and rapid rough-machining methodology for spark eroding suitable ceramic compositions based on material removal by thermal shock induced spalling, as opposed to conventional melting mechanisms. The principal materials studied were TiB2 dispersion toughened SiC, and Syalon501 - a commercially available TiN toughened sialon ceramic specifically designed for spark erosion. A preliminary study was also carried out on a range of SiC:B4C composites. Machinability and material performance were assessed where appropriate using machining parameters, material removal rate tests, surface analysis, four-point flexure testing, and tool wear. The machining technologies which supported the different mechanisms of material removal were identified, and each mechanism investigated by analysis of captured debris and sectioning of the workpiece. The SiC:B4C composites were found to be spark erodible only with B4C levels above 50% (by mass), and material removal was found to be solely by melting mechanisms. A SiC:TiB2 composition with the addition of 26.5% TiB2 (by mass) was found to be more machinable than a composition with 10% TiB2 (by mass), achieving greater material removal rates owing to its higher electrical conductivity. An in-depth study of the latter (10%TiB2) SiC composition and Syalon501 revealed surprisingly robust materials. Under conventional sparking (no arcing), material was removed by combined dissociation, melting and evaporation. Syalon501 in particular behaved with a high degree of predictability, and neither material could be made to spall under conventional sparking. However, by imposing conditions which deliberately induced arcing, both compositions spalled large flakes of material (up to several hundred microns across) in the localised region of the arc-strike. Examination of captured debris and fracture facets of the spall interface revealed the existence of small "penny cracks", each characterised by the presence of a dispersed particle (of greater thermal expansion) at its centre acting as a stress- raising nucleation point under the intense thermal loading of arcing. Sub-surface cracks in the near horizontal and near-vertical planes were discovered in line with published models based on the application of a hot-spot to brittle material, and evidence of discrete crack propagation under the thermally punctuated pulses of successive sparking was identified. Similar sub-surface cracking was also confirmed in Syalon501 which had been subjected to arcing. Sectioning of the workpiece revealed shallow sub-surface cracks which followed the profile of the machined surface in the near-horizontal plane, and which often limited the extent of near-vertical cracking to the layer of material above the crack, thereby offering the potential for a reliable and fast "planning" technique in which material would be removed in shallow layers. This research has shown that the possibility exists for increased material removal rates and improved process efficiency under a spalling-based machining regime, in which layers of material are released by thermal-shock induced fracture caused by arcing. The viability of developing a new rough-machining technology for ceramics, in which material is "planed" away prior to fine surface finishing by conventional spark erosion has, therefore, been successfully demonstrated.

Comparison of efficiency of the retreatment procedure between Wave One Gold and Wave One systems by Micro-CT and confocal microscopy: an in vitro study.

PubMed

Canali, Lyz Cristina Furquim; Duque, Jussaro Alves; Vivan, Rodrigo Ricci; Bramante, Clovis Monteiro; Só, Marcus Vinícius Reis; Duarte, Marco Antonio Hungaro

2018-04-19

To compare, by Micro-CT and confocal laser scanning microscopy (CLSM), the ability of the Wave One Gold and Wave One systems to remove filling material from mesial canals of mandibular molars, effective time spent; quantity of extruded material, and percentage of sealer in the dentinal tubules after retreatment and re-obturation procedures. Ten first mandibular molars (n = 20 mesial canals) were prepared and filled with gutta-percha and Endofill sealer mixed with Rhodamine B dye using the single cone technique. After 7 days, the canals were scanned using a high-definition micro-computer tomography with 19-mm voxel size and divided into two groups (n = 10) according to the system used in retreatment: group 1, Wave One (WO), and group 2, Wave One Gold (WG). After removing filling material with the primary file of each system, the WO 40/.08 and WG 35/.06 files were used. After using each file, a new scanning was performed and the residual filling material and extruded filling material were measured. The effective time spent to remove the canal filling was measured after each instrument. After retreatment, the teeth were re-obturated with gutta-percha and AH Plus sealer mixed with fluorescein dye using the single-cone technique. The roots were sectioned at 2, 4 and 6 mm and analysed by CLSM to measure the percentage of remaining sealer and the sealer of the new root canal filling. The data were statistically compared (P < 0.05). Both systems presented a similar volume of filling material remaining in the canals after the use of the two instruments, similar residual and new material in the dentinal tubules, and similar extrusion of material (P > 0.05). When using WO 25, the operator spent significantly less effective time than when using WG 25 (P < 0.05); however, use of WG 35 and WO 40 required a similar time to remove filling material from the canals (P > 0.05). Neither of the two systems removed all the filling material. The WG system presented similar ability in removing filling and extruded material in comparison with WO system. The effective time spent was shorter for WO 25 than for WG 25. Wave One Gold can be an alternative to perform retreatment considering that in comparison with Wave One, there was no difference in filling material removal capacity and extruded materials. There was only difference in the effective time spent, in which the operator spent more time with WG 25 than with WO 25.

Improvement of magnetorheological finishing surface quality by nanoparticle jet polishing

NASA Astrophysics Data System (ADS)

Peng, Wenqiang; Li, Shengyi; Guan, Chaoliang; Shen, Xinmin; Dai, Yifan; Wang, Zhuo

2013-04-01

Nanoparticle jet polishing (NJP) is presented as a posttreatment to remove magnetorheological finishing (MRF) marks. In the NJP process the material is removed by chemical impact reaction, and the material removal rate of convex part is larger than that of the concave part. Smoothing thus can progress automatically in the NJP process. In the experiment, a silica glass sample polished by MRF was polished by NJP. Experiment results showed the MRF marks were removed clearly. The uniform polishing process shows that the NJP process can remove the MRF marks without destroying the original surface figure. The surface root-mean-square roughness is improved from 0.72 to 0.41 nm. power spectral density analysis indicates the surface quality is improved, and the experimental result validates effective removal of MRF marks by NJP.

Synthesis and Characteristics of HgCdSe for IR Detection

DTIC Science & Technology

2014-03-11

Photoelectron Spectroscopy Study of Oxide Removal Using Atomic Hydrogen for Large-Area II–VI Material Growth, Journal of Electronic Materials...Workshop on the Physics and Chemistry of II-VI Materials, Chicago IL (October 1-3, 2013) “Use of Atomic Hydrogen to Prepare GaSb(211)B and GaSb(100...Workshop on the Physics and Chemistry of II-VI Materials, Chicago IL (October, 2011) "Xray photoelectron spectroscopy study of oxide removal using

Development of Metal-impregnated Single Walled Carbon Nanotubes for Toxic Gas Contaminant Control in Advanced Life Support Systems

NASA Technical Reports Server (NTRS)

Cinke, Martin; Li, Jing; Chen, Bin; Wignarajah, Kanapathipillai; Pisharody, Suresh A.; Fisher, John W.; Delzeit, Lance; Meyyappan, Meyya; Partridge, Harry; Clark, Kimberlee

2003-01-01

The success of physico-chemical waste processing and resource recovery technologies for life support application depends partly on the ability of gas clean-up systems to efficiently remove trace contaminants generated during the process with minimal use of expendables. Highly purified metal-impregnated carbon nanotubes promise superior performance over conventional approaches to gas clean-up due to their ability to direct the selective uptake gaseous species based both on the nanotube s controlled pore size, high surface area, and ordered chemical structure that allows functionalization and on the nanotube s effectiveness as a catalyst support material for toxic contaminants removal. We present results on the purification of single walled carbon nanotubes (SWCNT) and efforts at metal impregnation of the SWCNT's.

Benefit from NASA

NASA Image and Video Library

2004-04-15

The Waterblast Research Cell supports development of automated systems that remove thermal protection materials and coatings from space flight hardware. These systems remove expended coatings without harsh chemicals or damaging underlying material. Potential applications of this technology include the removal of coatings from industrial machinery, aircraft, and other large structures. Use of the robot improves worker safety by reducing the exposure of persornel to high-pressure water. This technology is a proactive alternative to hazardous chemical strippers.

REMOVAL OF LEGACY PLUTONIUM MATERIALS FROM SWEDEN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunn, Kerry A.; Bellamy, J. Steve; Chandler, Greg T.

2013-08-18

U.S. Department of Energy’s National Nuclear Security Administration (NNSA) Office of Global Threat Reduction (GTRI) recently removed legacy plutonium materials from Sweden in collaboration with AB SVAFO, Sweden. This paper details the activities undertaken through the U.S. receiving site (Savannah River Site (SRS)) to support the characterization, stabilization, packaging and removal of legacy plutonium materials from Sweden in 2012. This effort was undertaken as part of GTRI’s Gap Materials Program and culminated with the successful removal of plutonium from Sweden as announced at the 2012 Nuclear Security Summit. The removal and shipment of plutonium materials to the United States wasmore » the first of its kind under NNSA’s Global Threat Reduction Initiative. The Environmental Assessment for the U.S. receipt of gap plutonium material was approved in May 2010. Since then, the multi-year process yielded many first time accomplishments associated with plutonium packaging and transport activities including the application of the of DOE-STD-3013 stabilization requirements to treat plutonium materials outside the U.S., the development of an acceptance criteria for receipt of plutonium from a foreign country, the development and application of a versatile process flow sheet for the packaging of legacy plutonium materials, the identification of a plutonium container configuration, the first international certificate validation of the 9975 shipping package and the first intercontinental shipment using the 9975 shipping package. This paper will detail the technical considerations in developing the packaging process flow sheet, defining the key elements of the flow sheet and its implementation, determining the criteria used in the selection of the transport package, developing the technical basis for the package certificate amendment and the reviews with multiple licensing authorities and most importantly integrating the technical activities with the Swedish partners.« less

Regeneration performance and carbon consumption of semi-coke and activated coke for SO₂ and NO removal.

PubMed

Ding, Song; Li, Yuran; Zhu, Tingyu; Guo, Yangyang

2015-08-01

To decrease the operating cost of flue gas purification technologies based on carbon-based materials, the adsorption and regeneration performance of low-price semi-coke and activated coke were compared for SO2 and NO removal in a simulated flue gas. The functional groups of the two adsorbents before and after regeneration were characterized by a Fourier transform infrared (FTIR) spectrometer, and were quantitatively assessed using temperature programmed desorption (TPD) coupled with FTIR and acid-base titration. The results show that semi-coke had higher adsorption capacity (16.2% for SO2 and 38.6% for NO) than activated coke because of its higher content of basic functional groups and lactones. After regeneration, the adsorption performance of semi-coke decreased because the number of active functional groups decreased and the micropores increased. Semi-coke had better regeneration performance than activated coke. Semi-coke had a larger SO2 recovery of 7.2% and smaller carbon consumption of 12% compared to activated coke. The semi-coke carbon-based adsorbent could be regenerated at lower temperatures to depress the carbon consumption, because the SO2 recovery was only reduced a small amount. Copyright © 2015. Published by Elsevier B.V.

Bagworm bags as portable armour against invertebrate predators

PubMed Central

2016-01-01

Some animals have evolved the use of environmental materials as “portable armour” against natural enemies. Portable bags that bagworm larvae (Lepidoptera: Psychidae) construct using their own silk and plant parts are generally believed to play an important role as a physical barrier against natural enemies. However, no experimental studies have tested the importance of bags as portable armour against predators. To clarify the defensive function, I studied the bagworm Eumeta minuscula and a potential predator Calosoma maximoviczi (Coleoptera: Carabidae). Under laboratory conditions, all bagworm larvae were attacked by carabid adults, but successfully defended themselves against the predators’ mandibles using their own bags. The portable bags, which are composed mainly of host plant twigs, may function as a physical barrier against predator mandibles. To test this hypothesis, I removed the twig bags and replaced some with herb leaf bags; all bag-removed larvae were easily caught and predated by carabids, while all bag-replaced larvae could successfully defend themselves against carabid attacks. Therefore, various types of portable bags can protect bagworm larvae from carabid attacks. This is the first study to test the defensive function of bagworm portable bags against invertebrate predators. PMID:26893969

SO x /NO x Removal from Flue Gas Streams by Solid Adsorbents: A Review of Current Challenges and Future Directions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rezaei, Fateme; Rownaghi, Ali A.; Monjezi, Saman

One of the main challenges in the power and chemical industries is to remove generated toxic or environmentally harmful gases before atmospheric emission. To comply with stringent environmental and pollutant emissions control regulations, coal-fired power plants must be equipped with new technologies that are efficient and less energy-intensive than status quo technologies for flue gas cleanup. While conventional sulfur oxide (SOx) and nitrogen oxide (NOx) removal technologies benefit from their large-scale implementation and maturity, they are quite energy-intensive. In view of this, the development of lower-cost, less energy-intensive technologies could offer an advantage. Significant energy and cost savings can potentiallymore » be realized by using advanced adsorbent materials. One of the major barriers to the development of such technologies remains the development of materials that are efficient and productive in removing flue gas contaminants. In this review, adsorption-based removal of SOx/NOx impurities from flue gas is discussed, with a focus on important attributes of the solid adsorbent materials as well as implementation of the materials in conventional and emerging acid gas removal technologies. The requirements for effective adsorbents are noted with respect to their performance, key limitations, and suggested future research directions. The final section includes some key areas for future research and provides a possible roadmap for the development of technologies for the removal of flue gas impurities that are more efficient and cost-effective than status quo approaches.« less

Remediation of lead and cadmium from simulated groundwater in loess region in northwestern China using permeable reactive barrier filled with environmentally friendly mixed adsorbents.

PubMed

Fan, Chunhui; Gao, Yalin; Zhang, Yingchao; Dong, Wanqing; Lai, Miao

2018-01-01

Permeable reactive barrier (PRB) is potentially effective for groundwater remediation, especially using environmentally friendly mixed fillers in representative areas, such as semi-arid loess region in northwestern China. The mixed materials, including corn straw (agricultural wastes), fly ash (industrial wastes), zeolite synthesized from fly ash (reutilized products), and iron-manganese nodule derived from loess (materials with regional characteristics) in northwestern China, were chosen as PRB media to reduce the contents of lead and cadmium in simulated groundwater. A series of lab-scale column experiments were investigated, and the response surface methodology (RSM) was used to optimize the working process; Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) were applied to further reveal the reaction mechanism. It shows that the purification efficiencies are more acceptable when the concentrations of lead and cadmium are approximately 7 and 0.7 mg/L, respectively, at 25 °C in weakly acidic solution, and functional groups of -OH and C=C play an important role for contaminants removal. The mixed adsorbents used are effective to remove lead and cadmium in groundwater. This is the first report on the removal of lead and cadmium from groundwater in loess region in northwestern China using PRB filled with environmentally friendly mixed adsorbents.

Multilevel integration of patternable low-κ material into advanced Cu BEOL

NASA Astrophysics Data System (ADS)

Lin, Qinghuang; Chen, S. T.; Nelson, A.; Brock, P.; Cohen, S.; Davis, B.; Fuller, N.; Kaplan, R.; Kwong, R.; Liniger, E.; Neumayer, D.; Patel, J.; Shobha, H.; Sooriyakumaran, R.; Purushothaman, S.; Spooner, T.; Miller, R.; Allen, R.; Wisnieff, R.

2010-04-01

In this paper, we wish to report, for the first time, on a simple, low-cost, novel way to form dual-damascene copper (Cu) on-chip interconnect or Back-End-Of-the-Line (BEOL) structures using a patternable low dielectric constant (low-κ) dielectric material concept. A patternable low-κ dielectric material combines the functions of a traditional resist and a dielectric material into one single material. It acts as a traditional resist during patterning and is subsequently converted to a low-κ dielectric material during a post-patterning curing process. No sacrificial materials (separate resists or hardmasks) and their related deposition, pattern transfer (etch) and removal (strip) are required to form dual-damascene BEOL patterns. We have successfully demonstrated multi-level dual-damascene integration of a novel patternable low-κ dielectric material into advanced Cu BEOL. This κ=2.7 patternable low-κ material is based on the industry standard SiCOH-based (silsesquioxane polymer) material platform and is compatible with 248 nm optical lithography. Multilevel integration of this patternable low-κ material at 45 nm node Cu BEOL fatwire levels has been demonstrated with very high electrical yields using the current manufacturing infrastructure.

CoFFEE: Corrections For Formation Energy and Eigenvalues for charged defect simulations

NASA Astrophysics Data System (ADS)

Naik, Mit H.; Jain, Manish

2018-05-01

Charged point defects in materials are widely studied using Density Functional Theory (DFT) packages with periodic boundary conditions. The formation energy and defect level computed from these simulations need to be corrected to remove the contributions from the spurious long-range interaction between the defect and its periodic images. To this effect, the CoFFEE code implements the Freysoldt-Neugebauer-Van de Walle (FNV) correction scheme. The corrections can be applied to charged defects in a complete range of material shapes and size: bulk, slab (or two-dimensional), wires and nanoribbons. The code is written in Python and features MPI parallelization and optimizations using the Cython package for slow steps.

Low-Dielectric Constant Polyimide Nanoporous Films: Synthesis and Properties

NASA Astrophysics Data System (ADS)

Mehdipour-Ataei, S.; Rahimi, A.; Saidi, S.

2007-08-01

Synthesis of high temperature polyimide foams with pore sizes in the nanometer range was developed. Foams were prepared by casting graft copolymers comprising a thermally stable block as the matrix and a thermally labile material as the dispersed phase. Polyimides derived from pyromellitic dianhydride with new diamines (4BAP and BAN) were used as the matrix material and functionalized poly(propylene glycol) oligomers were used as a thermally labile constituent. Upon thermal treatment the labile blocks were subsequently removed leaving pores with the size and shape of the original copolymer morphology. The polyimides and foamed polyimides were characterized by some conventional methods including FTIR, H-NMR, DSC, TGA, SEM, TEM, and dielectric constant.

Zirconium-modified materials for selective adsorption and removal of aqueous arsenic

DOEpatents

Zhao, Hongting; Moore, Robert C.

2004-11-30

A method, composition, and apparatus for removing contaminant species from an aqueous medium comprising: providing a material to which zirconium has been added, the material selected from one or more of zeolites, cation-exchangeable clay minerals, fly ash, mesostructured materials, activated carbons, cellulose acetate, and like porous and/or fibrous materials; and contacting the aqueous medium with the material to which zirconium has been added. The invention operates on all arsenic species in the form of arsenate, arsenite and organometallic arsenic, with no pretreatment necessary (e.g., oxidative conversion of arsenite to arsenate).

Ultraviolet stability and contamination analysis of Spectralon diffuse reflectance material

NASA Technical Reports Server (NTRS)

Stiegman, Albert E.; Bruegge, Carol J.; Springsteen, Arthur W.

1993-01-01

A detailed chemical analysis was carried out on Spectralon, a highly Lambertian, diffuse reflectance material. Results of this investigation unambiguously identified the presence of an organic (hydrocarbon) impurity intrinsic to the commercial material. This impurity could be removed by a vacuum bake-out procedure and was identified as the cause of optical changes (degradation) that occur in the material when exposed to UV light. It was found that when this impurity was removed, the Spectralon material was photochemically stable and maintained its reflectance properties even after extensive solar UV exposure.

Water hyacinths and alligator weeds for removal of silver, cobalt, and strontium from polluted waters

NASA Technical Reports Server (NTRS)

Wolverton, B. C.; Mcdonald, R. C.

1975-01-01

Water hyacinths and alligator weeds demonstrated the ability to rapidly remove heavy metals from an aqueous system by root absorption and concentration. Water hyacinths demonstrated the ability to remove 0.439 mg of silver, 0.568 mg of cobalt, and 0.544 mg of strontium in an ionized form per gram of dry plant material in a 24-hour period. Alligator weeds removed a maximum of 0.439 mg of silver, 0.130 mg of cobalt, and 0.161 mg of strontium per gram of dry plant material per day.

Neutron vibrational spectroscopic studies of novel tire-derived carbon materials

DOE PAGES

Li, Yunchao; Cheng, Yongqiang; Daemen, Luke L.; ...

2017-08-11

Sulfonated tire-derived carbons have been demonstrated to be high value-added carbon products of tire recycling in several energy storage system applications including lithium, sodium, potassium ion batteries and supercapacitors. In this paper, we compared different temperature pyrolyzed sulfonated tire-derived carbons with commercial graphite and unmodified/non-functionalized tire-derived carbon by studying the surface chemistry and properties, vibrational spectroscopy of the molecular structure, chemical bonding such as C–H bonding, and intermolecular interactions of the carbon materials. The nitrogen adsorption–desorption studies revealed the tailored micro and meso pore size distribution of the carbon during the sulfonation process. XPS and neutron vibrational spectra showed thatmore » the sulfonation of the initial raw tire powders could remove the aliphatic hydrogen containing groups ([double bond splayed left]CH 2 and –CH 3 groups) and reduce the number of heteroatoms that connect to carbon. The absence of these functional groups could effectively improve the first cycle efficiency of the material in rechargeable batteries. Meanwhile, the introduced –SO 3H functional group helped in producing terminal H at the edge of the sp 2 bonded graphite-like layers. Finally, this study reveals the influence of the sulfonation process on the recovered hard carbon from used tires and provides a pathway to develop and improve advanced energy storage materials.« less

Process for removing sulfur from coal

DOEpatents

Aida, T.; Squires, T.G.; Venier, C.G.

1983-08-11

A process is disclosed for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

Mechanical Mercury Extraction Process® Test Results at Combie Reservoir

NASA Astrophysics Data System (ADS)

Monohan, C.; Alpers, C. N.; Marvin-DiPasquale, M. C.

2016-12-01

More than 4,500,000 kilograms (10,000,000 pounds) of mercury (Hg) were used during hydraulic and hard rock mining during the California Gold Rush era, and it is estimated that 10-30% of liquid Hg was lost to the environment. Mercury is entrained in river gravels containing hydraulic mining debris and is incorporated into the aquatic food chain, causing numerous environmental and public health problems for California communities today. One of the problems is that Hg-contaminated sediment accumulates in water-supply reservoirs such as the Combie Reservoir. Sand miners and irrigation districts have removed these accumulated materials for more than 30 years. The Combie Reservoir Sediment and Mercury Removal Project is to dredge Hg-contaminated sediment from Combie Reservoir while implementing an innovative recovery process to remove the free elemental Hg (Hg(0)) from the dredged material. The project is estimated to take 3 to 5 years to complete and would remove and treat an estimated 100,000 cubic meters (135,000 cubic yards) of sediment from the upstream end of Combie Reservoir. The dredged material will be processed with the Pegasus Mercury Extraction Process® which passes the material through a specialized centrifuge, thereby removing Hg(0) as well as other heavy minerals, including gold (Au) and Au-Hg amalgam. To measure the effectiveness of removal process, multiple equipment tests were conducted in September and October 2009. Total Hg (THg), methylmercury (MeHg) and reactive Hg(II) (operationally defined by reduction of divalent inorganic Hg(II) to Hg(0) with tin(II)) were measured in heads (input material) and tails (output material) from replicate closed system tests. Mass balances were calculated for water, sediment and the above forms of Hg to estimate Hg removal effectiveness in different grain-size fractions. The free Hg(0) in the sand size fraction (> 0.063 mm) that was removed by the Pegasus Mercury Extraction Process® represents approximately 93% of the calculated THg in the head material. Process and equipment design modifications are being pursued to improve Hg recovery from the fine-grained fraction (< 0.063 mm). [Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Drying of pulverized material with heated condensible vapor

DOEpatents

Carlson, L.W.

1984-08-16

Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fines, on the outer lateral surface thereof. The cooled collection fines are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized materials then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal. 2 figs.

Characterization of Atmospheric Pressure Plasma Torch and the Surface Interaction for Material Removal

NASA Astrophysics Data System (ADS)

McWilliams, Anthony Joseph

An atmospheric pressure plasma torch has been developed and characterized for removal of organic based coatings. The focus of the Strategic Environmental Research & Development Program (SERDP) project WP-1762, that funded the bulk of this dissertation work, is removal of paint from US Navy vessels. The goal is to develop a novel technology for coating removal that is capable of reducing the amount of environmental waste produced during the commonly used grit blasting process. The atmospheric pressure air plasma torch was identified as having the capacity to remove the paint systems while using only compressed air and electricity as a media-less removal system with drastically reduced waste generation. Any improvements to the existing technology need to be based on scientific knowledge and thus the plasma removal mechanisms or material warranted investigation. The removal of material does not show a strong relation to the plasma parameters of power, frequency, and gas flow, nor is there a strong relation to the presences of inorganic fillers impeding or altering the removal rates. The underlying removal mechanisms also do not show a strong correlation to the rotational temperature of the plasma but do show a strong correlation to the optical emission intensity. Primarily, the emission from atomic oxygen and molecular nitrogen were identified significant contributors and were investigated further. The plasma feed gas was then varied from the nitrogen and oxygen ratio present in ambient air to pure nitrogen to identify the effect of oxygen on the removal mechanism. From these experiments it was concluded that the oxygen present in air does contribute to the overall removal mechanism; however, it is not the sole contributing factor with the other major factor being nitrogen.

Self-assembly modified-mushroom nanocomposite for rapid removal of hexavalent chromium from aqueous solution with bubbling fluidized bed.

PubMed

Xu, Fei; Liu, Xu; Chen, Yijiao; Zhang, Ke; Xu, Heng

2016-05-18

A self-assembled modified Pleurotus Cornucopiae material (SMPM) combined with improved Intermittent Bubbling Fluidized Bed (IBFB) was investigated to remove the hexavalent chromium ions in aqueous solution. After the modification, the powder-like raw material gradually self-assembled together to SMPM, which had crinkly porous structure, improved the Cr-accommodation ability in a sound manner. Optimized by Taguchi method, Cr(VI) removal efficiency was up to 75.91% and 48.01% for 100 mg/L and 500 mg/L initial concentration of Cr(VI), respectively. Results indicated that the metal removal was dependent on dosage of adsorbent, particle diameter and treatment time. The experimental data obtained from the biosorption process was successfully correlated with Freundlich isotherm model. Thermodynamic study indicated the endothermic nature of the process. The results confirmed that self-assembly modified Pleurotus Cornucopiae material could be applied for the removal of heavy metal from wastewater in continuous fluidized bed process.

Self-assembly modified-mushroom nanocomposite for rapid removal of hexavalent chromium from aqueous solution with bubbling fluidized bed

PubMed Central

Xu, Fei; Liu, Xu; Chen, Yijiao; Zhang, Ke; Xu, Heng

2016-01-01

A self-assembled modified Pleurotus Cornucopiae material (SMPM) combined with improved Intermittent Bubbling Fluidized Bed (IBFB) was investigated to remove the hexavalent chromium ions in aqueous solution. After the modification, the powder-like raw material gradually self-assembled together to SMPM, which had crinkly porous structure, improved the Cr-accommodation ability in a sound manner. Optimized by Taguchi method, Cr(VI) removal efficiency was up to 75.91% and 48.01% for 100 mg/L and 500 mg/L initial concentration of Cr(VI), respectively. Results indicated that the metal removal was dependent on dosage of adsorbent, particle diameter and treatment time. The experimental data obtained from the biosorption process was successfully correlated with Freundlich isotherm model. Thermodynamic study indicated the endothermic nature of the process. The results confirmed that self-assembly modified Pleurotus Cornucopiae material could be applied for the removal of heavy metal from wastewater in continuous fluidized bed process. PMID:27188258

Self-assembly modified-mushroom nanocomposite for rapid removal of hexavalent chromium from aqueous solution with bubbling fluidized bed

NASA Astrophysics Data System (ADS)

Xu, Fei; Liu, Xu; Chen, Yijiao; Zhang, Ke; Xu, Heng

2016-05-01

A self-assembled modified Pleurotus Cornucopiae material (SMPM) combined with improved Intermittent Bubbling Fluidized Bed (IBFB) was investigated to remove the hexavalent chromium ions in aqueous solution. After the modification, the powder-like raw material gradually self-assembled together to SMPM, which had crinkly porous structure, improved the Cr-accommodation ability in a sound manner. Optimized by Taguchi method, Cr(VI) removal efficiency was up to 75.91% and 48.01% for 100 mg/L and 500 mg/L initial concentration of Cr(VI), respectively. Results indicated that the metal removal was dependent on dosage of adsorbent, particle diameter and treatment time. The experimental data obtained from the biosorption process was successfully correlated with Freundlich isotherm model. Thermodynamic study indicated the endothermic nature of the process. The results confirmed that self-assembly modified Pleurotus Cornucopiae material could be applied for the removal of heavy metal from wastewater in continuous fluidized bed process.

Computer Controlled Optical Surfacing With Orbital Tool Motion

NASA Astrophysics Data System (ADS)

Jones, Robert A.

1985-10-01

Asymmetric aspheric optical surfaces are very difficult to fabricate using classical techniques and laps the same size as the workpiece. Opticians can produce such surfaces by grinding and polishing, using small laps with orbital tool motion. However, hand correction is a time consuming process unsuitable for large optical elements. Itek has developed Computer Controlled Optical Surfacing (CCOS) for fabricating such aspheric optics. Automated equipment moves a nonrotating orbiting tool slowly over the workpiece surface. The process corrects low frequency surface errors by figuring. The velocity of the tool assembly over the workpiece surface is purposely varied. Since the amount of material removal is proportional to the polishing or grinding time, accurate control over material removal is achieved. The removal of middle and high frequency surface errors is accomplished by pad smoothing. For a soft pad material, the pad will compress to fit the workpiece surface producing greater pressure and more removal at the surface high areas. A harder pad will ride on only the high regions resulting in removal only for those locations.