Sample records for primenenie nanostrukturnogo materiala

  1. Selected characteristics of a new polyvinyl siloxane impression material--a randomized clinical trial.


    Blatz, Markus B; Sadan, Avishai; Burgess, John O; Mercante, Donald; Hoist, Stefan


    This study evaluated the ability of a new polyvinyl siloxane impression material (Affinis, Coltène/Whaledent, material A) to obtain final impressions free of bubbles and voids for indirect fixed cuspal-coverage restorations. The results were compared to a control polyvinyl siloxane impression material (material B). Both materials were handled by inexperienced clinicians (undergraduate dental students) in student clinics. One-hundred and thirty patients who were treated in the Louisiana State University School of Dentistry Junior Student Clinic for indirect fixed cuspal-coverage restorations and who met the inclusion criteria were randomly assigned to either one of two treatment groups, group A (n = 65) or group B (n = 65). Two calibrated examiners evaluated the first impression of prepared posterior teeth at a magnification of 10x for acceptability (no voids or bubbles). Position of tooth, type of preparation, preparation finish line (Class I-V), and gingival bleeding scores were recorded. All statistical tests were performed with the level of significance set at .05. The Fisher-Freeman-Halton test did not reveal significant associations between material and gingival bleeding score (P = .492). Significant differences in the location of the preparation finish line between materials were observed (P = .0096); material A was more frequently used in cases where the preparation finish line was located at least 2 mm subgingivally. Logistic regression was used to assess the effect of the material on the success of the impression (acceptable/ unacceptable). Material was highly significant in the logistic model (P < .001) with an odds in favor of an acceptable impression being eight times higher with material A than with material B (odds ratio = 8.00; 95% confidence index for odds ratio: 2.832, 22.601). The 60/65 (92.3%) impressions made with material A and 39/65 (60%) impressions made with material B were rated "acceptable." The new polyvinyl siloxane impression material provided a significantly higher proportion of impressions free of bubbles and voids than the control polyvinyl siloxane material.

  2. Remobilization of pentavalent antimony and vanadium from a granular iron hydroxide material--a comparative study of different leaching systems.


    Kolbe, Falko; Weiss, Holger; Wennrich, Rainer; Lorenz, Wilhelm Georg; Daus, Birgit


    The remobilization of antimony and vanadium from previously loaded commercial granular ferric-hydroxide GEH material (intended for water treatment) was examined by using a sequential extraction procedure and three different leaching systems to evaluate their physicochemical mobility and potential availability under different simulated environmental conditions. A classical batch extraction, an extraction cell (EC) and rotating-coiled columns (RCC) were used as extraction systems. For each system it could be shown that the content of ion-exchangeable antimony and vanadium in previously loaded material is negligible (<1.5%). The oxyanions were sorbed strongly and could be predominantly remobilized through reducing agents, which means through dissolution of the iron (hydr)oxide matrix. The major advantages of dynamic systems in comparison to batchwise fractionation technique are the drastically reduced extraction time and the possibility of generating information to the leaching kinetics. It is shown that the efficiency of the three leaching systems is quite different employing Wenzel's sequential fractionation protocol. Only by working with RCC, the iron (hydr)oxide matrix was completely dissolved within four steps resulting in the total mobilization of antimony and vanadium. EC seems to be less suitable for leaching studies of Sb and V sorbed on iron(hydr)oxide. The remobilizable proportion of the several fractions was lower in comparison to batch and RCC and seems to be a result of an agglomeration of the GEH in the EC device. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. [Trans-Arterial Chemoembolization Therapy for Refractory Advanced Non-Small Cell Lung Cancer with Spherical Embolic Material--A Single Case Report].


    Kennoki, Norifumi; Hori, Shinichi; Yuki, Takeo; Sueyoshi, Satoshi; Hori, Atsushi


    Here, we report the use of trans-arterial chemoembolization for primary lung cancer. The patient was a 56-year-old woman with refractory Stage Ⅳ non-small cell lung cancer who had been treated with repeated systemic chemotherapy. The primary lesion in the right lower lobe was 75 mm in size, with multiple lung metastases. It invaded the right main bronchus and caused severe cough. Radiotherapy was not indicated because of the size and extent of the lesion. During a period of 6 months, chemoembolization of the bilateral bronchial arteries using cisplatin 20 mg, docetaxel 20 mg, and 5-FU 250 mg with HepaSphere (super-absorbent polymer microspheres) was performed 5 times. Twenty mg of docetaxel was loaded onto 25 mg of HepaSphere. The microspheres were between 50 and 100 microns in the dry state. The endpoint of embolization was not stasis but the reduction of arterial flow. There were no serious complications during or after the procedure. Immediately after the first session, the patient's cough was significantly improved. After 5 sessions of the same treatment, the primary lesion was reduced to 48 mm and the level of CEA was reduced from 9.8 to 4.3 ng/mL. The invasion to the right main bronchus was reduced. The patient has been well without any symptoms for 9 months after initiation of trans-arterial chemoembolization.

  4. Soft tissue augmentation in connection to dental implant treatment using a synthetic, porous material--a case series with a 6-month follow-up.


    Friberg, Bertil; Jemt, Torsten


    Bony defects/concavities in the aesthetic zone of maxillae may interfere with the results of prosthetic procedures by producing shading superior to the crown. Such regions can be augmented either by bone or soft tissue autografts, allografts, or xenografts. Tissue shrinkage is thus anticipated, and a method to objectively measure the tissue change is valuable. The aim of this study was to evaluate the use of a synthetic, porous material made of polyurethaneurea for buccal soft tissue augmentation in connection with implant placement in the maxillary front region. Further, to measure over time the change in buccal contour using a computerized technique. Ten patients received 12 Artelon® cylinders (5 × 10 mm) in connection to implant placement. Preoperative and postoperative (at 3 and 6 months) study casts were obtained for computer measurements, using the preoperative reference model as a base. The volume created between the surfaces of the reference model and each of the two following superimposed models was measured in cubic millimeter. Differences in volume from pretreatment to 3 and 6 months, respectively, were compared. The clinical observation during follow-up showed normal healing. The increase in mean buccal tissue volume was 50 mm(3) (SD 18) after 3 months and 43 mm(3) (SD 21) after 6 months, measured over a 6 mm × 8 mm area in the maxillary front region, in comparison to before insertion of the cylinder. The reduction from 3 to 6 months was not statistically significant (p = .17). A synthetic, porous material for soft tissue augmentation was tested in connection to implant placement in the aesthetic zone of maxillae. The buccal contour was followed-up for 6 months using a computer volumetric technique on preoperative and postoperative study casts. Measured tissue volume showed an obvious increase during the study period. The material was biologically well received. © 2010 Wiley Periodicals, Inc.

  5. Prioritizing stream types according to their potential risk to receive crop plant material--A GIS-based procedure to assist in the risk assessment of genetically modified crops and systemic insecticide residues.


    Bundschuh, Rebecca; Kuhn, Ulrike; Bundschuh, Mirco; Naegele, Caroline; Elsaesser, David; Schlechtriemen, Ulrich; Oehen, Bernadette; Hilbeck, Angelika; Otto, Mathias; Schulz, Ralf; Hofmann, Frieder


    Crop plant residues may enter aquatic ecosystems via wind deposition or surface runoff. In the case of genetically modified crops or crops treated with systemic pesticides, these materials may contain insecticidal Bt toxins or pesticides that potentially affect aquatic life. However, the particular exposure pattern of aquatic ecosystems (i.e., via plant material) is not properly reflected in current risk assessment schemes, which primarily focus on waterborne toxicity and not on plant material as the route of uptake. To assist in risk assessment, the present study proposes a prioritization procedure of stream types based on the freshwater network and crop-specific cultivation data using maize in Germany as a model system. To identify stream types with a high probability of receiving crop materials, we developed a formalized, criteria-based and thus transparent procedure that considers the exposure-related parameters, ecological status--an estimate of the diversity and potential vulnerability of local communities towards anthropogenic stress--and availability of uncontaminated reference sections. By applying the procedure to maize, ten stream types out of 38 are expected to be the most relevant if the ecological effects from plant-incorporated pesticides need to be evaluated. This information is an important first step to identifying habitats within these stream types with a high probability of receiving crop plant material at a more local scale, including accumulation areas. Moreover, the prioritization procedure developed in the present study may support the selection of aquatic species for ecotoxicological testing based on their probability of occurrence in stream types having a higher chance of exposure. Finally, this procedure can be adapted to any geographical region or crop of interest and is, therefore, a valuable tool for a site-specific risk assessment of crop plants carrying systemic pesticides or novel proteins, such as insecticidal Bt toxins, expressed in genetically modified crops. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. When Does Retrieval Induce Forgetting and when Does It Induce Facilitation? Implications for Retrieval Inhibition, Testing Effect, and Text Processing

    ERIC Educational Resources Information Center

    Chan, Jason C. K.


    Retrieval practice can enhance long-term retention of the tested material (the testing effect), but it can also impair later recall of the nontested material--a phenomenon known as retrieval-induced forgetting (Anderson, M. C., Bjork, R. A., & Bjork, E. L. (1994). "Remembering can cause forgetting: retrieval dynamics in long-term memory." "Journal…

  7. When Does Retrieval Induce Forgetting and when Does It Induce Facilitation? Implications for Retrieval Inhibition, Testing Effect, and Text Processing

    ERIC Educational Resources Information Center

    Chan, Jason C. K.


    Retrieval practice can enhance long-term retention of the tested material (the testing effect), but it can also impair later recall of the nontested material--a phenomenon known as retrieval-induced forgetting (Anderson, M. C., Bjork, R. A., & Bjork, E. L. (1994). "Remembering can cause forgetting: retrieval dynamics in long-term memory." "Journal…

  8. Ammonia Optical Sensing by Microring Resonators.


    Passaro, Vittorio M N; Dell'Olio, Francesco; De Leonardis, Francesco


    A very compact (device area around 40 μm²) optical ammonia sensor based on amicroring resonator is presented in this work. Silicon-on-insulator technology is used insensor design and a dye doped polymer is adopted as sensing material. The sensor exhibitsa very good linearity and a minimum detectable refractive index shift of sensing materialas low as 8x10(-5), with a detection limit around 4 ‰.

  9. Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding

    DTIC Science & Technology


    applied to a prototypical (plain) low- carbon steel (AISI 1005) to predict the distribution of various crystalline phases within the as-welded material...a prototypical (plain) low- carbon steel (AISI 1005) to predict the distribution of various crystalline phases within the as-welded material micro...arc voltage/current should be placed between the short- circuiting and spray transfer/mode counterparts. Typically, using carbon dioxide as a

  10. Rock mechanics. Second edition

    SciTech Connect

    Jumikis, A.R.


    Rock Mechanics, 2nd Edition deals with rock as an engineering construction material-a material with which, upon which, and within which civil engineers build structures. It thus pertains to hydraulic structures engineering; to highway, railway, canal, foundation, and tunnel engineering; and to all kinds of rock earthworks and to substructures in rock. Major changes in this new edition include: rock classification, rock types and description, rock testing equipment, rock properties, stability effects of discontinuity and gouge, grouting, gunite and shotcrete, and Lugeon's water test. This new edition also covers rock bolting and prestressing, pressure-grouted soil anchors, and rock slope stabilization.

  11. NASA Historical Data Book. Volume 6; NASA Space Applications, Aeronautics and Space Research and Technology, Tracking and Data Acquisition/Support Operations, Commercial Programs and

    NASA Technical Reports Server (NTRS)

    Rumerman, Judy A.


    This sixth volume of the NASA Historical Data Book is a continuation of those earlier efforts. This fundamental reference tool presents information, much of it statistical, documenting the development of several critical areas of NASA responsibility for the period between 1979 and 1988. This volume includes detailed information on the space applications effort, the development and operation of aeronautics and space research and technology programs, tracking and data acquisition/space operations, commercial programs, facilities and installations, personnel, and finances and procurement during this era. Special thanks are owed to the student research assistants who gathered and input much of the tabular material-a particularly tedious undertaking. There are numerous people at NASA associated with historical study, technical information, and the mechanics of publishing who helped in myriad ways in the preparation of this historical data book.

  12. Patterns in flowing sand: understanding the physics of granular flow.


    Börzsönyi, Tamás; Ecke, Robert E; McElwaine, Jim N


    Dense granular flows are often unstable and form inhomogeneous structures. Although significant advances have been recently made in understanding simple flows, instabilities of such flows are often not understood. We present experimental and numerical results that show the formation of longitudinal stripes that arise from instability of the uniform flowing state of granular media on a rough inclined plane. The form of the stripes depends critically on the mean density of the flow with a robust form of stripes at high density that consists of fast sliding pluglike regions (stripes) on top of highly agitated boiling material--a configuration reminiscent of the Leidenfrost effect when a droplet of liquid lifted by its vapor is hovering above a hot surface.

  13. Why do beliefs about intelligence influence learning success? A social cognitive neuroscience model.


    Mangels, Jennifer A; Butterfield, Brady; Lamb, Justin; Good, Catherine; Dweck, Carol S


    Students' beliefs and goals can powerfully influence their learning success. Those who believe intelligence is a fixed entity (entity theorists) tend to emphasize 'performance goals,' leaving them vulnerable to negative feedback and likely to disengage from challenging learning opportunities. In contrast, students who believe intelligence is malleable (incremental theorists) tend to emphasize 'learning goals' and rebound better from occasional failures. Guided by cognitive neuroscience models of top-down, goal-directed behavior, we use event-related potentials (ERPs) to understand how these beliefs influence attention to information associated with successful error correction. Focusing on waveforms associated with conflict detection and error correction in a test of general knowledge, we found evidence indicating that entity theorists oriented differently toward negative performance feedback, as indicated by an enhanced anterior frontal P3 that was also positively correlated with concerns about proving ability relative to others. Yet, following negative feedback, entity theorists demonstrated less sustained memory-related activity (left temporal negativity) to corrective information, suggesting reduced effortful conceptual encoding of this material-a strategic approach that may have contributed to their reduced error correction on a subsequent surprise retest. These results suggest that beliefs can influence learning success through top-down biasing of attention and conceptual processing toward goal-congruent information.

  14. Single Stage Silicone Border Molded Closed Mouth Impression Technique-Part II.


    Solomon, E G R


    Functioning of a complete denture depends to a great extent on the impression technique. Several impression techniques have been described in the literature since the turn of this century when Greene [Clinical courses in dental prothesis, 1916] brothers introduced the first scientific system of recording dental impression. Advocates of each technique have their own claim of superiority over the other. The introduction of elastomeric impression materials [Skinner and Cooper, J Am Dent Assoc 51:523-536, 1955] has made possible new techniques of recording impression for complete denture construction. These rubber like materials are of two types; one has a polysulfide base and is popularily known as polysulfide rubber (Thiokol and Mercaptan). The other variety has a silicone base known as silicone rubber or silicone elastomer. Silicone elastomers are available in four different consistencies; a thin easy flowing light bodied material,a creamy medium bodied material, a highly viscous heavy bodied material and a kneadable putty material. This paper describes an active closed mouth impression technique with one stage border molding using putty silicone material as a substitute for low fusing compound.

  15. Nonreversible immobilization of water-borne plutonium onto self-assembled adlayers of silanized humic materials.


    Shcherbina, Natalia S; Kalmykov, Stepan S; Karpiouk, Leonid A; Ponomarenko, Sergey A; Hatfield, Kirk; Haire, Richard; Perminova, Irina V


    The objective was to study plutonium partitioning between immobile and mobile humic materials at the water-solid interfaces. Immobilization of the humic materials on solid supports was performed in situ using self-adhesive silanized humic derivatives. The presence of the humic adlayers on solid supports was shown to significantly enhance Pu sorption and its retention under both steady state and dynamic conditions. While plutonium may exist in multiple oxidations states plus colloidal forms, the major thrust in this work was to study the behavior of most mobile--the PuO2(+) form in dilute solutions. The values of the plutonium partition coefficients (Kd) between water and humics-coated silica gels after 10 days exposure reached 1.6 × 10(4) L · kg(-1) at pH 7.5 under anaerobic conditions with a total plutonium concentration of 1.2 × 10(-8) M exceeding those for the uncoated SiO2 (6.3 × 10(2) L · kg(-1)). Column tests showed substantial sequestration of water-borne plutonium (up to 73%) on the humics-coated silica gels. Remobilization experiments conducted under batch conditions at different pH values (3.5, 4.5, 7.5) showed that no more than 3% of the sequestered Pu was remobilized from the humics-coated silica gels by treatment with dissolved humic materials at environmentally relevant pH of 7.5. Consequently, silanized humic materialas can be seen as both molecular probes and as potent candidate materials for scavenging mobile Pu from an aqueous phase.

  16. Identification and Characterization of Well-Preserved Impact Ejecta Deposits Using THEMIS Global Infrared Mosaics

    NASA Astrophysics Data System (ADS)

    Hill, J. R.; Christensen, P. R.


    The Thermal Emission Imaging System (THEMIS) onboard the 2001 Mars Odyssey spacecraft has been acquiring infrared observations of the Martian surface for nearly thirteen years. Daytime infrared images from the first twelve years of the mission have previously been used to generate a complete global mosaic, while nighttime infrared images have been used to generate a near-global mosaic between 60°N-60°S. A combined product has been generated by overlaying the daytime global mosaic with a colorized version of the nighttime global mosaic, resulting in a near-global map that can be used to more easily identify surface features with unique thermal characteristics.Well-preserved ejecta deposits associated with fresh impact craters are readily identifiable in the combined map by their characteristic nighttime temperature pattern, which is controlled by variations in the thermal inertia of the ejecta material. The pattern consists of relatively high thermal inertia material in and around the crater, an inner ejecta ring composed of intermediate thermal inertia material and an outer ejecta ring composed of low thermal inertia material.A near-global survey (60°N-60°S) of these well-preserved ejecta deposits has shown that the vast majority occur in a small region covering northern Terra Sirenum and eastern Daedalia Planum, with a smaller concentration present in Syria Planum. A comparison of THEMIS and Viking images has verified that the larger craters and ejecta deposits were present at the time of the Viking mission and are not the result of more recent impacts. The survey also identified similarly fresh impact craters across the planet that are lacking an outer ring of low thermal inertia ejecta material, possibly due to erosion of the original ejecta deposits. This suggests that local conditions in Terra Sirenum, Daedalia Planum and Syria Planum are favorable for the long-term preservation of the fine-grained component of fresh impact ejecta deposits.

  17. Electric field effects in RUS measurements.


    Darling, Timothy W; Allured, Bradley; Tencate, James A; Carpenter, Michael A


    Much of the power of the Resonant Ultrasound Spectroscopy (RUS) technique is the ability to make mechanical resonance measurements while the environment of the sample is changed. Temperature and magnetic field are important examples. Due to the common use of piezoelectric transducers near the sample, applied electric fields introduce complications, but many materials have technologically interesting responses to applied static and RF electric fields. Non-contact optical, buffered, or shielded transducers permit the application of charge and externally applied electric fields while making RUS measurements. For conducting samples, in vacuum, charging produces a small negative pressure in the volume of the material--a state rarely explored. At very high charges we influence the electron density near the surface so the propagation of surface waves and their resonances may give us a handle on the relationship of electron density to bond strength and elasticity. Our preliminary results indicate a charge sign dependent effect, but we are studying a number of possible other effects induced by charging. In dielectric materials, external electric fields influence the strain response, particularly in ferroelectrics. Experiments to study this connection at phase transformations are planned. The fact that many geological samples contain single crystal quartz suggests a possible use of the piezoelectric response to drive vibrations using applied RF fields. In polycrystals, averaging of strains in randomly oriented crystals implies using the "statistical residual" strain as the drive. The ability to excite vibrations in quartzite polycrystals and arenites is explored. We present results of experimental and theoretical approaches to electric field effects using RUS methods.

  18. Transformation of Metal-Organic Frameworks/Coordination Polymers into Functional Nanostructured Materials: Experimental Approaches Based on Mechanistic Insights.


    Lee, Kyung Joo; Lee, Jae Hwa; Jeoung, Sungeun; Moon, Hoi Ri


    , the appropriate choice of precursor MOFs and heat treatment can be expected to yield carbon-based nanomaterials. We address the relationship between the nature of the parent MOF and the porosity of the daughter carbon material-a controversial issue in the synthesis of porous carbons. Based on an understanding of the mechanism of MOF conversion, morphologically or compositionally advanced materials are synthesized by adopting appropriate MOF precursors and thermolysis conditions. Despite the progressive understanding of conversion phenomena of MOFs/CPs, this research field still has rooms to be explored and developed, ultimately in order to precisely control the properties of resultant nanomaterials. In this sense, we should pay more attention to the mechanism investigations of MOF conversion. We believe this Account will facilitate a deeper understanding of MOF/CP conversion routes and will accelerate further development in this field.

  19. The origin of high sodium bicarbonate waters in the Atlantic and Gulf Coastal Plains

    USGS Publications Warehouse

    Foster, M.D.


    Some sodium bicarbonate waters at depth in the Atlantic and Gulf Coastal Plains have the same bicarbonate content as the shallower calcium bicarbonate waters in the same formation and appear to be the result of replacement of calcium by sodium through the action of base-exchange minerals. Others, however, contain several hundred parts per million more of bicarbonate than any of the calcium bicarbonate waters and much more bicarbonate than can be attributed to solution of calcium carbonate through the action of carbon dioxide derived from the air and soil. As the waters in the Potomac group (Cretaceous) are all low in sulphate and as the environmental conditions under which the sediments of the Potomac group were deposited do not indicate that large amounts of sulphate are available for solution, it does not seem probable that carbon dioxide generated by chemical or biochemical breakdown of sulphate is responsible for the high sodium bicarbonate waters in this area. Sulphate as a source of oxygen is not necessary for the generation of carbon dioxide by carbonaceous material. Oxygen is an important constituent of carbonaceous material and carbon dioxide is a characteristic decomposition product of such material-as, for example, peat and lignite. Experimental work showed that distilled water, calcium bicarbonate water, and sodium bicarbonate water, after contact with lignite, calcium carbonate, and permutite (a base-exchange material), had all increased greatly in sodium bicarbonate content and had become similar in chemical character and in mineral content to high sodium bicarbonate waters found in the Coastal Plain. The tests indicated that carbonaceous material can act as a source of carbon dioxide, which, when dissolved in water, enables it to take into solution more calcium carbonate. If base-exchange materials are also present to replace calcium with sodium, a still greater amount of bicarbonate can be held in solution. The presence of carbonaceous material

  20. Oral Mucosal Lesions Associated with Smokers and Chewers – A Case-Control Study in Chennai Population

    PubMed Central

    Masthan, Mahaboob Kader; Narayanasamy, Aravindha Babu


    Aims and Objectives To determine the association of oral mucosal lesions in a group of Chennai population aged 15 years and above with smoking and chewing habits. To also determine the dose-response relationship of these habits associated with the risk of oral mucosal lesions. Materiala and Methods The study was undertaken with 450 subjects with smoking and/or chewing habits aged 15 years and over gathered through random selection in Chennai, India. Subjects with alcohol intake were excluded from the study. Based on the habits the study group was categorized into smokers, chewers and mixed (smoking+chewing). One hundred and fifty subjects diagnosed with oral mucosal lesions designated as “cases” and 300 lesion-free “controls”, frequency matched for age, sex, habit and family income were assessed during the study. The study protocol included a visual oral soft tissue examination and a questionnaire-based interview. In addition, those requiring further examination, scalpel biopsies were performed to establish a definitive diagnosis. Results Irrespective of the type of habit, 78% of cases smoked and/or chewed for more than 10 years as compared to 37.4% of the control group. Similarly, 71.3% of cases smoked and/or chewed more than 5 times per day as compared to 25.6% of the control group. Eleven habits related mucosal lesions of the oral cavity were encountered. Smoker’s melanosis was the most common oral mucosal lesion followed by Oral submucous fibrosis and Leukoplakia. Dose-response relationships were observed for both duration and frequency of habits on the risk of oral mucosal lesions. Conclusion The result of the present study provides information on the association of oral mucosal lesions in smokers, chewers and patients with mixed habits. The mucosal lesions encountered included a few potentially malignant conditions and oral squamous cell carcinoma. Habits were more prevalent in men thus more lesions were encountered in males than in females

  1. Investigations on comminution of sheared prismatic granular materials using the discrete element method

    NASA Astrophysics Data System (ADS)

    Weatherley, D.; Wruck, B.; Hancock, W.; Chitombo, G. P.


    adjacent spheres. Finally, the convex polyhedra are filled with bonded spherical particles to simulate the brittle-elastic response of the granular material.As in previous studies, the granular assembly is then compressed to various confining pressures and sheared to large total shear strains. During these so-called annular shear-cell experiments, each breakage event is analysed to determine whether it qualifies as an abrasion event or bulk-splitting event. The size-distribution of fragments within the shear-cell is also monitored throughout the experiments. Preliminary results confirm the qualitative relationships between applied loads and breakage mechanisms described above. Quantitative comparisons with previous DEM studies will be presented at the meeting. These experiments were conducted using ESyS-Particle, an Open Source DEM simulation package for multi-core PCs or supercomputers [3].

  2. Interim measure conceptual design for remediation at the former CCC/USDA grain storage facility at Centralia, Kansas : pilot test and remedy implementation.

    SciTech Connect

    LaFreniere, L. M.; Environmental Science Division


    carbon tetrachloride in groundwater and soil, the CCC/USDA recommends initial short-term, field-scale pilot testing of a remedial approach that employs in situ chemical reduction (ISCR), in the form of a commercially available material marketed by Adventus Americas, Inc., Freeport, Illinois ( If the pilot test is successful, it will be followed by a request for KDHE authorization of full implementation of the ISCR approach. In the recommended ISCR approach, the Adventus EHC{reg_sign} material--a proprietary mixture of food-grade organic carbon and zero-valent iron--is introduced into the subsurface, where the components are released slowly into the formation. The compounds create highly reducing conditions in the saturated zone and the overlying vadose zone. These conditions foster chemical and biological reductive dechlorination of carbon tetrachloride. The anticipated effective lifetime of the EHC compounds following injection is 1-5 yr. Although ISCR is a relatively innovative remedial approach, the EHC technology has been demonstrated to be effective in the treatment of carbon tetrachloride contamination in groundwater and has been employed at a carbon tetrachloride contamination site elsewhere in Kansas (Cargill Flour Mill and Elevator, Wellington, Kansas; KDHE Project Code C209670158), with the approval of the KDHE. At Centralia, the CCC/USDA recommends use of the ISCR approach initially in a short-term pilot test addressing the elevated carbon tetrachloride levels identified in one of three persistently highly contaminated areas ('hot-spot areas') in the groundwater plume. In this test, a three-dimensional grid pattern of direct-push injection points will be used to distribute the EHC material (in slurry or aqueous form) throughout the volume of the contaminated aquifer and (in selected locations) the vadose zone in the selected hot-spot area. Injection of the EHC material will be conducted by a licensed contractor, under the